diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml index 5aa3029c..ff6c33de 100644 --- a/.github/workflows/ci.yaml +++ b/.github/workflows/ci.yaml @@ -5,10 +5,14 @@ on: branches: - main - master + - v3 + tags: + - 'v*' pull_request: branches: - main - master + - v3 jobs: setup: @@ -19,7 +23,7 @@ jobs: go-version: '^1.26' steps: - name: Checkout code - uses: actions/checkout@v6 + uses: actions/checkout@v7 - name: Set up Go id: setup-go @@ -34,7 +38,7 @@ jobs: contents: read steps: - name: Checkout code - uses: actions/checkout@v6 + uses: actions/checkout@v7 - name: Set up Go uses: actions/setup-go@v6 @@ -45,7 +49,7 @@ jobs: run: go test -v ./... -coverprofile=coverage.txt -covermode=atomic - name: Upload coverage to Codecov - uses: codecov/codecov-action@v6 + uses: codecov/codecov-action@v7 with: file: ./coverage.txt token: ${{ secrets.CODECOV_TOKEN }} @@ -57,7 +61,7 @@ jobs: contents: read steps: - name: Checkout code - uses: actions/checkout@v6 + uses: actions/checkout@v7 - name: Set up Go uses: actions/setup-go@v6 @@ -79,7 +83,7 @@ jobs: pull-requests: write steps: - name: Checkout code - uses: actions/checkout@v6 + uses: actions/checkout@v7 - name: Generate changelog uses: release-drafter/release-drafter@v7 @@ -93,7 +97,7 @@ jobs: contents: read steps: - name: Checkout code - uses: actions/checkout@v6 + uses: actions/checkout@v7 - name: Generate Go Report Card uses: creekorful/goreportcard-action@v1.0 diff --git a/.gitignore b/.gitignore index 702292ea..da1ca2d1 100644 --- a/.gitignore +++ b/.gitignore @@ -29,6 +29,9 @@ _testmain.go # Benchmarking cpu.out + +# Coverage +coverage.out .idea stockfish .worktrees/ @@ -36,3 +39,5 @@ stockfish skills-lock.json CONTEXT.md docs/ +AGENTS.md +.scratch/ diff --git a/.golangci.yml b/.golangci.yml index 4c79773f..dd52006a 100644 --- a/.golangci.yml +++ b/.golangci.yml @@ -1,371 +1,189 @@ -# This code is licensed under the terms of the MIT license https://opensource.org/license/mit -# Copyright (c) 2021 Marat Reymers - -## Golden config for golangci-lint v1.62.2 -# -# This is the best config for golangci-lint based on my experience and opinion. -# It is very strict, but not extremely strict. -# Feel free to adapt and change it for your needs. - -run: - # Timeout for analysis, e.g. 30s, 5m. - # Default: 1m - timeout: 3m - - -# This file contains only configs which differ from defaults. -# All possible options can be found here https://github.com/golangci/golangci-lint/blob/master/.golangci.reference.yml -linters-settings: - cyclop: - # The maximal code complexity to report. - # Default: 10 - max-complexity: 30 - # The maximal average package complexity. - # If it's higher than 0.0 (float) the check is enabled - # Default: 0.0 - package-average: 10.0 - - errcheck: - # Report about not checking of errors in type assertions: `a := b.(MyStruct)`. - # Such cases aren't reported by default. - # Default: false - check-type-assertions: true - - exhaustive: - # Program elements to check for exhaustiveness. - # Default: [ switch ] - check: - - switch - - map - - exhaustruct: - # List of regular expressions to exclude struct packages and their names from checks. - # Regular expressions must match complete canonical struct package/name/structname. - # Default: [] - exclude: - # std libs - - "^net/http.Client$" - - "^net/http.Cookie$" - - "^net/http.Request$" - - "^net/http.Response$" - - "^net/http.Server$" - - "^net/http.Transport$" - - "^net/url.URL$" - - "^os/exec.Cmd$" - - "^reflect.StructField$" - # public libs - - "^github.com/Shopify/sarama.Config$" - - "^github.com/Shopify/sarama.ProducerMessage$" - - "^github.com/mitchellh/mapstructure.DecoderConfig$" - - "^github.com/prometheus/client_golang/.+Opts$" - - "^github.com/spf13/cobra.Command$" - - "^github.com/spf13/cobra.CompletionOptions$" - - "^github.com/stretchr/testify/mock.Mock$" - - "^github.com/testcontainers/testcontainers-go.+Request$" - - "^github.com/testcontainers/testcontainers-go.FromDockerfile$" - - "^golang.org/x/tools/go/analysis.Analyzer$" - - "^google.golang.org/protobuf/.+Options$" - - "^gopkg.in/yaml.v3.Node$" - - funlen: - # Checks the number of lines in a function. - # If lower than 0, disable the check. - # Default: 60 - lines: 100 - # Checks the number of statements in a function. - # If lower than 0, disable the check. - # Default: 40 - statements: 50 - # Ignore comments when counting lines. - # Default false - ignore-comments: true - - gochecksumtype: - # Presence of `default` case in switch statements satisfies exhaustiveness, if all members are not listed. - # Default: true - default-signifies-exhaustive: false - - gocognit: - # Minimal code complexity to report. - # Default: 30 (but we recommend 10-20) - min-complexity: 20 - - gocritic: - # Settings passed to gocritic. - # The settings key is the name of a supported gocritic checker. - # The list of supported checkers can be find in https://go-critic.github.io/overview. - settings: - captLocal: - # Whether to restrict checker to params only. - # Default: true - paramsOnly: false - underef: - # Whether to skip (*x).method() calls where x is a pointer receiver. - # Default: true - skipRecvDeref: false - - gomodguard: - blocked: - # List of blocked modules. - # Default: [] - modules: - - github.com/golang/protobuf: - recommendations: - - google.golang.org/protobuf - reason: "see https://developers.google.com/protocol-buffers/docs/reference/go/faq#modules" - - github.com/satori/go.uuid: - recommendations: - - github.com/google/uuid - reason: "satori's package is not maintained" - - github.com/gofrs/uuid: - recommendations: - - github.com/gofrs/uuid/v5 - reason: "gofrs' package was not go module before v5" - - govet: - # Enable all analyzers. - # Default: false - enable-all: true - # Disable analyzers by name. - # Run `go tool vet help` to see all analyzers. - # Default: [] - disable: - - fieldalignment # too strict - # Settings per analyzer. - settings: - shadow: - # Whether to be strict about shadowing; can be noisy. - # Default: false - strict: true - - inamedparam: - # Skips check for interface methods with only a single parameter. - # Default: false - skip-single-param: true - - mnd: - # List of function patterns to exclude from analysis. - # Values always ignored: `time.Date`, - # `strconv.FormatInt`, `strconv.FormatUint`, `strconv.FormatFloat`, - # `strconv.ParseInt`, `strconv.ParseUint`, `strconv.ParseFloat`. - # Default: [] - ignored-functions: - - args.Error - - flag.Arg - - flag.Duration.* - - flag.Float.* - - flag.Int.* - - flag.Uint.* - - os.Chmod - - os.Mkdir.* - - os.OpenFile - - os.WriteFile - - prometheus.ExponentialBuckets.* - - prometheus.LinearBuckets - - nakedret: - # Make an issue if func has more lines of code than this setting, and it has naked returns. - # Default: 30 - max-func-lines: 0 - - nolintlint: - # Exclude following linters from requiring an explanation. - # Default: [] - allow-no-explanation: [ funlen, gocognit, lll ] - # Enable to require an explanation of nonzero length after each nolint directive. - # Default: false - require-explanation: true - # Enable to require nolint directives to mention the specific linter being suppressed. - # Default: false - require-specific: true - - perfsprint: - # Optimizes into strings concatenation. - # Default: true - strconcat: false - - reassign: - # Patterns for global variable names that are checked for reassignment. - # See https://github.com/curioswitch/go-reassign#usage - # Default: ["EOF", "Err.*"] - patterns: - - ".*" - - rowserrcheck: - # database/sql is always checked - # Default: [] - packages: - - github.com/jmoiron/sqlx - - sloglint: - # Enforce not using global loggers. - # Values: - # - "": disabled - # - "all": report all global loggers - # - "default": report only the default slog logger - # https://github.com/go-simpler/sloglint?tab=readme-ov-file#no-global - # Default: "" - no-global: "all" - # Enforce using methods that accept a context. - # Values: - # - "": disabled - # - "all": report all contextless calls - # - "scope": report only if a context exists in the scope of the outermost function - # https://github.com/go-simpler/sloglint?tab=readme-ov-file#context-only - # Default: "" - context: "scope" - - tenv: - # The option `all` will run against whole test files (`_test.go`) regardless of method/function signatures. - # Otherwise, only methods that take `*testing.T`, `*testing.B`, and `testing.TB` as arguments are checked. - # Default: false - all: true - - +version: "2" linters: - disable-all: true + default: none enable: - ## enabled by default - - errcheck # checking for unchecked errors, these unchecked errors can be critical bugs in some cases - - gosimple # specializes in simplifying a code - - govet # reports suspicious constructs, such as Printf calls whose arguments do not align with the format string - - ineffassign # detects when assignments to existing variables are not used - - staticcheck # is a go vet on steroids, applying a ton of static analysis checks - - typecheck # like the front-end of a Go compiler, parses and type-checks Go code - #- unused # checks for unused constants, variables, functions and types - ## disabled by default - - asasalint # checks for pass []any as any in variadic func(...any) - - asciicheck # checks that your code does not contain non-ASCII identifiers - - bidichk # checks for dangerous unicode character sequences - - bodyclose # checks whether HTTP response body is closed successfully - - canonicalheader # checks whether net/http.Header uses canonical header - - copyloopvar # detects places where loop variables are copied (Go 1.22+) - - cyclop # checks function and package cyclomatic complexity - - dupl # tool for code clone detection - - durationcheck # checks for two durations multiplied together - - errname # checks that sentinel errors are prefixed with the Err and error types are suffixed with the Error - - errorlint # finds code that will cause problems with the error wrapping scheme introduced in Go 1.13 - #- exhaustive # checks exhaustiveness of enum switch statements - - fatcontext # detects nested contexts in loops - - forbidigo # forbids identifiers - - funlen # tool for detection of long functions - - gocheckcompilerdirectives # validates go compiler directive comments (//go:) - #- gochecknoglobals # checks that no global variables exist - - gochecknoinits # checks that no init functions are present in Go code - - gochecksumtype # checks exhaustiveness on Go "sum types" - - gocognit # computes and checks the cognitive complexity of functions - - goconst # finds repeated strings that could be replaced by a constant - - gocritic # provides diagnostics that check for bugs, performance and style issues - - gocyclo # computes and checks the cyclomatic complexity of functions - - godot # checks if comments end in a period - - goimports # in addition to fixing imports, goimports also formats your code in the same style as gofmt - - gomoddirectives # manages the use of 'replace', 'retract', and 'excludes' directives in go.mod - - gomodguard # allow and block lists linter for direct Go module dependencies. This is different from depguard where there are different block types for example version constraints and module recommendations - - goprintffuncname # checks that printf-like functions are named with f at the end - - gosec # inspects source code for security problems - - iface # checks the incorrect use of interfaces, helping developers avoid interface pollution - - intrange # finds places where for loops could make use of an integer range - #- lll # reports long lines - - loggercheck # checks key value pairs for common logger libraries (kitlog,klog,logr,zap) - - makezero # finds slice declarations with non-zero initial length - - mirror # reports wrong mirror patterns of bytes/strings usage - - mnd # detects magic numbers - - musttag # enforces field tags in (un)marshaled structs - - nakedret # finds naked returns in functions greater than a specified function length - - nestif # reports deeply nested if statements - - nilerr # finds the code that returns nil even if it checks that the error is not nil - - nilnil # checks that there is no simultaneous return of nil error and an invalid value - - noctx # finds sending http request without context.Context - - nolintlint # reports ill-formed or insufficient nolint directives - - nonamedreturns # reports all named returns - - nosprintfhostport # checks for misuse of Sprintf to construct a host with port in a URL - - perfsprint # checks that fmt.Sprintf can be replaced with a faster alternative - - predeclared # finds code that shadows one of Go's predeclared identifiers - - promlinter # checks Prometheus metrics naming via promlint - - protogetter # reports direct reads from proto message fields when getters should be used - - reassign # checks that package variables are not reassigned - - recvcheck # checks for receiver type consistency - - revive # fast, configurable, extensible, flexible, and beautiful linter for Go, drop-in replacement of golint - - rowserrcheck # checks whether Err of rows is checked successfully - - sloglint # ensure consistent code style when using log/slog - - spancheck # checks for mistakes with OpenTelemetry/Census spans - - sqlclosecheck # checks that sql.Rows and sql.Stmt are closed - - stylecheck # is a replacement for golint - - tenv # detects using os.Setenv instead of t.Setenv since Go1.17 - - testableexamples # checks if examples are testable (have an expected output) - - testifylint # checks usage of github.com/stretchr/testify - #- testpackage # makes you use a separate _test package - - tparallel # detects inappropriate usage of t.Parallel() method in your Go test codes - - unconvert # removes unnecessary type conversions - - unparam # reports unused function parameters - - usestdlibvars # detects the possibility to use variables/constants from the Go standard library - - wastedassign # finds wasted assignment statements - - whitespace # detects leading and trailing whitespace - - ## you may want to enable - #- decorder # checks declaration order and count of types, constants, variables and functions - #- exhaustruct # [highly recommend to enable] checks if all structure fields are initialized - #- gci # controls golang package import order and makes it always deterministic - #- ginkgolinter # [if you use ginkgo/gomega] enforces standards of using ginkgo and gomega - #- godox # detects FIXME, TODO and other comment keywords - #- goheader # checks is file header matches to pattern - #- inamedparam # [great idea, but too strict, need to ignore a lot of cases by default] reports interfaces with unnamed method parameters - #- interfacebloat # checks the number of methods inside an interface - #- ireturn # accept interfaces, return concrete types - #- prealloc # [premature optimization, but can be used in some cases] finds slice declarations that could potentially be preallocated - #- tagalign # checks that struct tags are well aligned - #- varnamelen # [great idea, but too many false positives] checks that the length of a variable's name matches its scope - #- wrapcheck # checks that errors returned from external packages are wrapped - #- zerologlint # detects the wrong usage of zerolog that a user forgets to dispatch zerolog.Event - - ## disabled - #- containedctx # detects struct contained context.Context field - #- contextcheck # [too many false positives] checks the function whether use a non-inherited context - #- depguard # [replaced by gomodguard] checks if package imports are in a list of acceptable packages - #- dogsled # checks assignments with too many blank identifiers (e.g. x, _, _, _, := f()) - #- dupword # [useless without config] checks for duplicate words in the source code - #- err113 # [too strict] checks the errors handling expressions - #- errchkjson # [don't see profit + I'm against of omitting errors like in the first example https://github.com/breml/errchkjson] checks types passed to the json encoding functions. Reports unsupported types and optionally reports occasions, where the check for the returned error can be omitted - #- exportloopref # [not necessary from Go 1.22] checks for pointers to enclosing loop variables - #- forcetypeassert # [replaced by errcheck] finds forced type assertions - #- gofmt # [replaced by goimports] checks whether code was gofmt-ed - #- gofumpt # [replaced by goimports, gofumports is not available yet] checks whether code was gofumpt-ed - #- gosmopolitan # reports certain i18n/l10n anti-patterns in your Go codebase - #- grouper # analyzes expression groups - #- importas # enforces consistent import aliases - #- maintidx # measures the maintainability index of each function - #- misspell # [useless] finds commonly misspelled English words in comments - #- nlreturn # [too strict and mostly code is not more readable] checks for a new line before return and branch statements to increase code clarity - #- paralleltest # [too many false positives] detects missing usage of t.Parallel() method in your Go test - #- tagliatelle # checks the struct tags - #- thelper # detects golang test helpers without t.Helper() call and checks the consistency of test helpers - #- wsl # [too strict and mostly code is not more readable] whitespace linter forces you to use empty lines - - -issues: - # Maximum count of issues with the same text. - # Set to 0 to disable. - # Default: 3 - max-same-issues: 50 - - exclude-rules: - - source: "(noinspection|TODO)" - linters: [ godot ] - - source: "//noinspection" - linters: [ gocritic ] - - path: "_test\\.go" - linters: - - bodyclose - - dupl - - errcheck + - asasalint + - asciicheck + - bidichk + - bodyclose + - canonicalheader + - copyloopvar + - cyclop + - dupl + - durationcheck + - errcheck + - errname + - errorlint + - fatcontext + - forbidigo + - funlen + - gocheckcompilerdirectives + - gochecknoinits + - gochecksumtype + - gocognit + - goconst + - gocritic + - gocyclo + - godot + - gomoddirectives + - gomodguard_v2 + - goprintffuncname + - gosec + - govet + - iface + - ineffassign + - intrange + - loggercheck + - makezero + - mirror + - musttag + - nakedret + - nestif + - nilerr + - nilnil + - noctx + - nolintlint + - nonamedreturns + - nosprintfhostport + - perfsprint + - predeclared + - promlinter + - protogetter + - reassign + - recvcheck + - revive + - rowserrcheck + - sloglint + - spancheck + - sqlclosecheck + - staticcheck + - testableexamples + - testifylint + - tparallel + - unconvert + - unparam + - usestdlibvars + - usetesting + - wastedassign + - whitespace + settings: + cyclop: + max-complexity: 30 + package-average: 10 + errcheck: + check-type-assertions: true + exhaustive: + check: + - switch + - map + funlen: + lines: 100 + statements: 50 + ignore-comments: true + gocognit: + min-complexity: 20 + gochecksumtype: + default-signifies-exhaustive: false + gocritic: + settings: + captLocal: + paramsOnly: false + underef: + skipRecvDeref: false + gomodguard_v2: + blocked: + - module: github.com/golang/protobuf + recommendations: + - google.golang.org/protobuf + reason: see https://developers.google.com/protocol-buffers/docs/reference/go/faq#modules + - module: github.com/satori/go.uuid + recommendations: + - github.com/google/uuid + reason: satori's package is not maintained + - module: github.com/gofrs/uuid + recommendations: + - github.com/gofrs/uuid/v5 + reason: gofrs' package was not go module before v5 + govet: + disable: + - fieldalignment + enable-all: true + settings: + shadow: + strict: true + inamedparam: + skip-single-param: true + nakedret: + max-func-lines: 0 + nolintlint: + require-explanation: true + require-specific: true + allow-no-explanation: - funlen - - goconst - - gosec - - noctx - - wrapcheck - - govet - - itrange - - staticcheck - - gochecknoglobals - - godot - gocognit + - lll + perfsprint: + strconcat: false + reassign: + patterns: + - .* + rowserrcheck: + packages: + - github.com/jmoiron/sqlx + sloglint: + no-global: all + context: scope + exclusions: + generated: lax + presets: + - comments + - common-false-positives + - legacy + - std-error-handling + rules: + - linters: + - godot + source: (noinspection|TODO) + - linters: + - gocritic + source: //noinspection + # G115: integer overflow conversions. Files/ranks are 0-7 and squares 0-63, + # so narrowing casts in bitboard math are provably in range. + - linters: + - gosec + text: G115 + # G404: math/rand is intentional for weighted polyglot book picks, not security. + - linters: + - gosec + text: G404 + - linters: + - bodyclose + - dupl + - errcheck + - funlen + - gochecknoglobals + - gocognit + - goconst + - godot + - gosec + - govet + - itrange + - noctx + - staticcheck + - wrapcheck + path: _test\.go + paths: + - third_party$ + - builtin$ + - examples$ +issues: + max-same-issues: 50 +formatters: + enable: + - goimports + exclusions: + generated: lax + paths: + - third_party$ + - builtin$ + - examples$ diff --git a/CHANGELOG.md b/CHANGELOG.md index cf9adc76..f97877fa 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -1,10 +1,94 @@ # Changelog All notable changes to this project will be documented in this file. See [conventional commits](https://www.conventionalcommits.org/) for commit guidelines. -- - - ## Unreleased - - - +## v3.0.0-beta.4 - 2026-07-24 + +#### Features +- add first-class Chess960 (Fischer Random) support: `Variant`, + `Chess960Setup(index)`, all 960 indexed starts, variant-aware legal + castling, Shredder-FEN output with Shredder/X-FEN input, Chess960 PGN + Variant/SetUp/FEN round-trips, and binary variant persistence (ADR-022). +- add Chess960 UCI support: `uciNotation` encodes castling in the + king-to-rook form (e.g. `e1h1`) and decodes both king-to-rook and + king-to-destination forms; the `uci` engine client negotiates + `UCI_Chess960` when the engine advertises it (ADR-023). +- add `EmptySetup`, `InitialSetup`, `Setup.SwapTurn`, and `Setup.Mirror` for + explicit position construction and analysis. +- relax FEN import: accept one to six fields, whitespace separators, and + fullmove number zero while preserving canonical output. + +#### Fixes +- add `ErrInvalidFEN` and `ErrInvalidPGN`; FEN/PGN parsing now wraps typed + sentinel errors so callers can use `errors.Is`. +- correct the v3 hash migration documentation: removed hash APIs have no + deprecated compatibility path. +- - - +## v3.0.0-beta.3 - 2026-07-20 + +#### Breaking Changes +- remove `Position.ChangeTurn()` (dead: no internal callers; turn mutation is not a public operation). +- remove `Game.Comments()` and the unexported `Game.comments` field; move annotations live on `MoveNode` (amends ADR-011). +- remove `GameScanned` and `TokenizeGame`; production PGN decode is lazy via `ParsePGN` / `PGNRecords` (and `parser.Parse` internally), driven by `lexerTokenSource`. The parser's `[]Token` test seam (`newParser`, `sliceTokenSource`, exported via `export_test.go:NewParser`) remains for state-machine unit tests (amends ADR-015). +- remove `PositionCursor`; promote its methods onto `MoveTree` as `Peek`, `Forward(idx)`, `Goto(node)`, `Reset`. Remove `Game.Cursor()` and `MoveTree.Cursor()`. Position snapshots continue via `MoveNode.Position()` / `Game.Position()`; `MoveTree.Peek()` is a zero-copy alias. `Goto` rejects nodes from a different tree. + +#### Removed +- remove dead internal helper `sortedCommandKeys` (pgn_renderer.go). + +#### Changed +- `Game.copy()` no longer aliases the move tree; every caller (`Clone`, `UnmarshalText`, `Split`, the test `PGN` option) sets the tree explicitly. Removes a latent shared-tree footgun without changing observable behaviour. +- consolidate PGN parse locality: `parsePGNText` and `lexerTokenSource` move from `framer.go` to `pgn.go`, next to the `Parser` they feed; `framer.go` is now honestly framing + the tokenize bridge. +- relabel the move-text notation layer as codec internals: header comments on `notation.go` and `notation_resolver.go` (renamed from `san_resolver.go`); no behaviour change (ADR-013, ADR-016). +- fix a cursor leak in PGN variation parsing on err returns: `parseVariation` (pgn.go) now uses `defer` to restore the active cursor so any err path inside a variation no longer strands the cursor inside the abandoned subtree (amends ADR-018). +- `opening`: `DefaultBook()` initializes the default book lazily via `sync.Once` on first call, honoring ADR-005. Importing the package no longer parses the embedded ECO table or risks a panic at load time; the first call pays the one-time parse cost. + +- - - + +## v3.0.0-beta.2 - 2026-06-29 + +#### Performance +- speed up full PGN-to-`Game` decoding by resolving SAN moves from direct candidate origins instead of scanning every legal move. +- reduce parsed position snapshot allocation count by storing board state directly inside internal `Position` values while keeping public defensive-copy APIs unchanged. +- keep full PGN decode behavior compatible for move tags, checks, castling, promotions, en passant, variations, and parser errors. + +#### Documentation +- document the v3 beta PGN decode performance profile and benchmark workflow. + +- - - + +## v3.0.0-beta.1 - 2026-06-19 + +v3 is a major redesign implementing [RFC-001](docs/adr/RFC-001-v3-redesign.md). +See [MIGRATION.md](MIGRATION.md) for a detailed guide to upgrading from v2. + +#### Breaking Changes +- module path changed to `github.com/corentings/chess/v3`. +- `Move` is now a 4-field value type (`s1`, `s2`, `promo`, `tags`), passed by value everywhere — `Move()` and `UnsafeMove()` accept `Move` not `*Move`. +- UCI command globals replaced with struct literals: `CmdUCI{}`, `CmdIsReady{}`, `CmdUCINewGame{}`, etc. +- `Game.Resign(color)` now returns `error`. +- `Game.Outcome` and `Game.Method` merged into `Outcome` + `OutcomeMethodPair` with `SetOutcomeMethod`/`ClearOutcome`. +- `Opening.Game()` returns a caller-owned clone of a pre-computed game. +- `Position.Hash()` (MD5) removed; use `Position.ZobristHash()` (uint64). `ZobristHasher`/`NewChessHasher`/`NewZobristHasher`/`ZobristHashToUint64`/`GetPolyglotHashBytes` also removed; see MIGRATION.md. +- `opening.Opening` renamed to `opening.Entry` (stuttered at call site). +- `(*PolyglotBook).GetRandomMove` → `RandomMove`; `GetChessMoves` → `ChessMoves` (no `Get` prefix on non-trivial operations). + +#### Features +- move tree with full variation support (`Variations`, `AddVariation`, `Split`). +- extracted PGN renderer (`PGNRenderer`, `DefaultPGNRenderer`, `RenderGameTo`). +- `Game.WritePGN(w)` for direct writer output. +- UCI Adapter pattern (`Adapter`, `SubprocessAdapter`, `FakeAdapter`) for testability. +- SVG image generation API: `SVG(w, *Position, *SVGOptions)` with `//go:embed` piece assets. +- opening book: `NewBook(io.Reader)` for custom data, `DefaultBook()` singleton. +- notation `Encode`/`Decode` with value semantics. + +#### Performance +- incremental Zobrist hashing with `Position.ZobristHash()`. +- mailbox `[64]Piece` for O(1) `Board.Piece()` lookups. +- zero-allocation `BookECO.Find` via compact `uint32` move keys. +- non-allocating `Position.SamePosition` fallback (direct struct comparison). +- `Position.ValidMovesUnsafe()` and `Position.ValidMovesIter()` for allocation-sensitive callers. ## v2.5.1 - 2026-06-19 #### Features diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md new file mode 100644 index 00000000..b42935d8 --- /dev/null +++ b/CONTRIBUTING.md @@ -0,0 +1,61 @@ +# Contributing + +## Development + +```bash +git clone https://github.com/corentings/chess/v3 +cd chess +go test ./... +``` + +## Linting + +Run `golangci-lint` before submitting changes: + +```bash +golangci-lint run +``` + +## Benchmarks + +Benchmarks live alongside the code in `_test.go` files. Run them with: + +```bash +go test -bench=. +``` + +### Comparative benchmarking with benchstat + +To compare performance between two versions (e.g., before and after a change), +use [`benchstat`](https://pkg.go.dev/golang.org/x/perf/cmd/benchstat): + +```bash +# Install benchstat (once) +go install golang.org/x/perf/cmd/benchstat@latest + +# Capture baseline on the reference commit +git stash +git checkout +go test -bench=. -count=10 > base.txt +git checkout - +git stash pop + +# Capture new measurements on your branch +go test -bench=. -count=10 > new.txt + +# Compare +benchstat base.txt new.txt +``` + +`-count=10` runs each benchmark ten times so benchstat can compute statistical +significance. For noisy environments, increase the count. + +### Perft regression testing + +The `perft_test.go` file contains perft (performance test) cases that verify +move-generation correctness against known node counts. These run as part of +`go test ./...` and should always pass. + +The `benchcmp/` directory contains tooling for comparing perft performance +against a C++ reference implementation. See `benchcmp/cpp/pgn_bench.cpp` and +`benchcmp/perft/bench_test.go`. diff --git a/MIGRATION.md b/MIGRATION.md new file mode 100644 index 00000000..2a27721b --- /dev/null +++ b/MIGRATION.md @@ -0,0 +1,280 @@ +# Migrating to v3 + +v3 is a breaking release focused on a smaller `Move` value type, extracted PGN +rendering, terminal-outcome guards, and modernized `opening`, `image`, and `uci` +packages. This guide lists every breaking change and how to update your code. + +## Module path + +The module path now reflects major version 3: + +```bash +go get -u github.com/corentings/chess/v3 +``` + +```go +import "github.com/corentings/chess/v3" +``` + +Update import paths in every sub-package you use (`/v3/image`, `/v3/opening`, +`/v3/uci`). + +## Move is a value, not a pointer + +`Move` is now a 4-field value (`s1`, `s2`, `promo`, `tags`). Tree navigation and +annotations live on the separate `MoveNode` type. `ValidMoves()` returns `[]Move` +and the move methods accept `Move` by value. + +```go +// v2 +moves := game.ValidMoves() +if err := game.Move(&moves[0], nil); err != nil { /* ... */ } + +// v3 +moves := game.ValidMoves() +node, err := game.Move(moves[0], nil) +if err != nil { /* ... */ } +_ = node +``` + +The same change applies to `UnsafeMove`, `PushMove`, `PushMoveText`, and +`UnsafePushMoveText`: they now return `(*MoveNode, error)`. The old +`PushMoveOptions` type is replaced by `MoveInsertOptions` with +`PromoteToMainLine`. + +Active move insertion remains a `Game` responsibility. Use the `Game` move +methods above to advance the current position so legality checks, terminal game +guards, and outcome evaluation stay in sync. `MoveTree` is exposed for +topology, cursor navigation, and variation traversal/editing; it does not have +a public active-move insertion method. +`Move.Clone()` has been removed — copy by assignment (`m2 := m1`) if you need a +value copy. + +In v2, `*Move` carried both the move data and its position/context. In v3 these +are split: `Move` is the bare value; `MoveNode` holds the tree position, +children, comments, and NAGs. Code that iterated moves and accessed position +data must now navigate via `MoveNode`: + +```go +// v2 +for _, m := range game.Moves() { + fmt.Println(m.Position().Turn()) // Move carried the resulting position +} + +// v3 +for _, node := range game.MoveTree().MainLine() { + fmt.Println(node.Position().Turn()) // Position() replays via tree cursor (ADR-018) +} +``` + +`game.Moves()` still returns `[]Move` (bare values, main line only). Use +`game.MoveTree()` for tree access: `tree.Root()`, `tree.Current()`, +`tree.MainLine()`, `tree.Continuations(node)`, `tree.Variations(node)`, +`node.Comments()`, `node.SetCommand(key, val)`, `node.SetComment(text)`, +`node.AddComment(text)`, `node.NAG()`, and `node.Children()` / `node.Parent()` +for variation traversal. + +## Notation APIs moved to move text codecs + +v3 removes the old notation structs and game notation methods. Use +`MoveTextCodec` values instead: + +- `AlgebraicNotation{}` -> `chess.SAN()` +- PGN import leniency -> `chess.PGNImportSAN()` +- `LongAlgebraicNotation{}` -> `chess.LongAlgebraic()` +- `UCINotation{}` -> `chess.UCI()` +- `Game.PushNotationMove(text, notation, opts)` -> `Game.PushMoveText(text, codec, opts)` +- `Game.UnsafePushNotationMove(text, notation, opts)` -> `Game.UnsafePushMoveText(text, codec, opts)` + +```go +game := chess.NewGame() +_, err := game.PushMoveText("e4", chess.SAN(), nil) +_, err = game.PushMoveText("e2e4", chess.UCI(), nil) +_, err = game.UnsafePushMoveText("e2e4", chess.UCI(), nil) +``` + +`PushMove` remains a strict SAN shorthand. Unsafe move text supports only fully +specified formats such as UCI and long algebraic notation; SAN and PGN import +SAN require legal resolution and are rejected by `UnsafePushMoveText`. + +## UCI commands are struct literals + +Global command values are now struct types. Pass them as struct literals: + +```go +// v2 +eng.Run(uci.CmdUCI, uci.CmdIsReady, uci.CmdUCINewGame) + +// v3 +eng.Run(uci.CmdUCI{}, uci.CmdIsReady{}, uci.CmdUCINewGame{}) +``` + +Commands that carry data (`CmdPosition`, `CmdGo`, `CmdSetOption`) are still +constructed as struct values: + +```go +eng.Run(uci.CmdPosition{Position: game.Position()}, uci.CmdGo{MoveTime: time.Second / 100}) +``` + +A new `Adapter` interface (`SubprocessAdapter`, `FakeAdapter`) backs the engine +and is injectable via `uci.NewWithAdapter`. `eng.SearchResults().BestMove` is now +a `chess.Move` value. + +## Image takes a Position and options + +`image.SVG` now accepts `*chess.Position` (instead of `*Board`) and an +`*SVGOptions` struct: + +```go +// v2 +image.SVG(w, board, image.Perspective(chess.Black)) + +// v3 +image.SVG(w, game.Position(), &image.SVGOptions{Perspective: chess.Black}) +``` + +`SVGOptions` exposes `SquareSize` (squares are no longer fixed at 45px). Piece +SVGs are embedded with `//go:embed` and cached at init. + +## Opening returns errors + +`NewBookECO()` parsed the ECO table on every call and called `log.Fatal` on +failure. It is replaced by a lazily-initialized singleton and a reader-based +constructor, both returning errors: + +```go +// v2 +book := opening.NewBookECO() // *BookECO, panics on error + +// v3 +book, err := opening.DefaultBook() // *BookECO, error, sync.Once +// or +book, err := opening.NewBook(r) // *BookECO, error, from any io.Reader +``` + +## Renamed identifiers + +Several v2 identifiers were renamed to follow Go naming conventions. All are +mechanical renames with no behaviour change; update the symbol at the call site. + +| v2 | v3 | Reason | +|---|---|---| +| `opening.Opening` | `opening.Entry` | Stuttered at the call site (`opening.Opening{}`). | +| `chess.GetPolyglotHashBytes` | _(removed)_ | Use `GetPolyglotHashes() []string` or convert a `uint64` via `binary.LittleEndian`. | +| `(*PolyglotBook).GetRandomMove` | `(*PolyglotBook).RandomMove` | `Get` prefix on a non-trivial operation. | +| `(*PolyglotBook).GetChessMoves` | `(*PolyglotBook).ChessMoves` | `Get` prefix on a non-trivial operation. | + +The unexported `newOpening` constructor is renamed `newEntry` to match. + +## Resign returns an error + +`Game.Resign` now validates state and returns an error instead of silently +no-oping after the game has ended: + +```go +// v2 +game.Resign(chess.Black) + +// v3 +if err := game.Resign(chess.Black); err != nil { + // game already ended, etc. +} +``` + +## Terminal outcome guards + +`Move`, `UnsafeMove`, and `PushMoveText` reject moves once the game has +reached a terminal outcome and return `chess.ErrGameAlreadyEnded`. Call +`Game.ClearOutcome()` to resume, or `Game.SetOutcomeMethod(method, outcome)` to +set an outcome explicitly with validation. `Split()` now recomputes each line's +outcome from its leaf position instead of copying the parent outcome. + +## Cursor → MoveTree + +`PositionCursor` is removed; `Game.Cursor()` and `MoveTree.Cursor()` are +removed. Navigate the tree directly: + +```go +t := game.MoveTree() +t.Reset() +for t.GoForward() { + // … reads via t.Peek() (zero-copy alias — MUST NOT mutate) + // or via game.Position() / node.Position() (defensive copies) +} +``` + +`MoveTree` gains `Peek`, `Forward(idx)`, `Goto(node)`, and `Reset` as public +methods. `Peek` returns the live cursor position without copying; the pointer +is invalidated by any navigation. `Goto` rejects nodes from a different tree +with `false`. + +## Null moves + +v3 adds explicit null move support. A null move flips the side to move without +moving any piece — used by engines for null-move pruning and by PGN +annotations to indicate a side passed. + +```go +g := chess.NewGame() +node, err := g.NullMove() // flips turn, serializes as "Z0" in PGN +``` + +`NewNullMove()` returns a `Move` carrying the `Null` tag. Null moves are never +returned by `ValidMoves()` and are rejected by `Game.Move`. Insert them via +`Game.NullMove()` or `Game.UnsafeMove(NewNullMove(), nil)`. When reading PGN, +the parser accepts five spellings: `Z0`, `Z1`, `--`, `@@`, and `0000`. The +renderer always writes `Z0` (ChessBase/Scid convention). + +## PGN rendering + +`Game.String()` still returns PGN and now delegates to `chess.DefaultPGNRenderer`. +For custom rendering use the extracted renderer: + +```go +r := &chess.PGNRenderer{} +fmt.Println(r.Render(game)) // string +r.RenderGameTo(game, w) // write to an io.Writer +``` + +`Game.WritePGN(w)` is also available. The renderer is stateless. + +## Hashing + +v3 consolidates position hashing around the cached `Position.ZobristHash() uint64` +for O(1) comparison and repetition detection. Several v2 hashing APIs are +removed with no direct replacement: + +- `Position.Hash() [16]byte` (MD5) is **removed**, not deprecated. Use + `Position.ZobristHash() uint64`. +- `ZobristHasher`, `NewChessHasher()`, `NewZobristHasher()` are removed. The + incremental hasher is now internal to `Position`. Callers who previously + hashed FEN strings without instantiating a `Position` should use the free + function `HashFromFEN(fen string) (uint64, error)`, which is a direct + replacement for `ZobristHasher.HashPosition(fen)`. +- `ZobristHashToUint64(hash string) uint64` is removed. Convert hex hashes + with `strconv.ParseUint(s, 16, 64)`. +- `GetPolyglotHashBytes(index int) []byte` is removed. Use + `GetPolyglotHashes() []string` for hex hashes; for the raw 8-byte + little-endian form, convert a `uint64` from `HashFromFEN` via + `binary.LittleEndian.PutUint64`. + +`Position.ValidMovesUnsafe()` and `Position.ValidMovesIter()` — +allocation-sensitive access for hot paths; see package docs for safety notes. +`Board.Piece()` uses an internal mailbox for O(1) lookup. + +## Polyglot book loading + +The `BookSource` interface and the `ReaderBookSource`, `BytesBookSource`, and +`FileBookSource` adapter types are removed. `LoadFromSource` is removed. Use +`LoadFromReader(io.Reader)` or `LoadFromBytes([]byte)` directly: + +```go +// v2 +book, err := chess.LoadFromSource(chess.NewBytesBookSource(data)) + +// v3 +book, err := chess.LoadFromBytes(data) +``` + +Both entry points read into memory; there is no streaming loader. Add one when +a caller needs it. diff --git a/README.md b/README.md index ff696265..4cd1fe38 100644 --- a/README.md +++ b/README.md @@ -1,19 +1,59 @@ -# Chess Library +# Chess — Go (Golang) chess library -[![GoDoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](https://godoc.org/github.com/corentings/chess) +[![pkg.go.dev](https://pkg.go.dev/badge/github.com/corentings/chess/v3.svg)](https://pkg.go.dev/github.com/corentings/chess/v3) [![Go Report Card](https://goreportcard.com/badge/corentings/chess)](https://goreportcard.com/report/corentings/chess) [![License](http://img.shields.io/badge/license-mit-blue.svg?style=flat-square)](https://raw.githubusercontent.com/corentings/chess/master/LICENSE) [![codecov](https://codecov.io/gh/corentings/chess/branch/main/graph/badge.svg)](https://codecov.io/gh/corentings/chess) [![CI](https://github.com/corentings/chess/actions/workflows/ci.yaml/badge.svg)](https://github.com/corentings/chess/actions/workflows/ci.yaml) [![Go Version](https://img.shields.io/github/go-mod/go-version/corentings/chess)](https://golang.org/doc/devel/release.html) +> A fast, well-tested Go chess library for move generation, PGN/FEN, UCI/Stockfish, +> opening books, and board image generation. + +## Features + +- Legal **move generation** via [bitboards](https://chessprogramming.org/Bitboards) +- **PGN** encode/decode, plus a streaming **PGNDecoder** for large game databases +- **FEN** encode/decode for board positions +- **UCI** client to drive engines like [Stockfish](https://stockfishchess.org/) +- **Opening book** exploration (ECO — Encyclopaedia of Chess Openings) +- SVG board **image generation** +- **Notations**: Algebraic (SAN), Long Algebraic, and UCI +- Checkmate, stalemate, repetition, and draw detection +- **Variations** support in the move tree +- `Unsafe*` fast-path APIs for performance-critical paths + +## Table of Contents + +- [Introduction](#introduction) +- [Recent Updates](#recent-updates) +- [Why I Forked](#why-i-forked) +- [Credits](#credits) +- [Disclaimer](#disclaimer) +- [Contributions](#contributions) +- [Repo Structure](#repo-structure) +- [Installation](#installation) +- [Usage](#usage) + - [Example Random Game](#example-random-game) + - [Example Stockfish v. Stockfish](#example-stockfish-v-stockfish) + - [Movement](#movement) + - [Outcome](#outcome) + - [PGN](#pgn) + - [FEN](#fen) + - [Notations](#notations) + - [Moves](#moves) +- [Perft](#perft) +- [Variation Tree](#variation-tree) +- [Performance](#performance) + - [Benchmarks](#benchmarks) + ## Introduction **chess** is a set of go packages which provide common chess utilities such as move generation, turn management, checkmate detection, PGN encoding, UCI interoperability, image generation, opening book exploration, and others. It is well tested and optimized for performance. -![rnbqkbnr/pppppppp/8/8/3P4/8/PPP1PPPP/RNBQKBNR b KQkq - 0 1](example.png) +![Chess board rendered from the starting position by the Go chess library](example.png) ## Recent Updates @@ -23,7 +63,7 @@ descriptive errors for invalid moves. This ensures consistent game correctness a **Performance Options**: Added unsafe variants for high-performance scenarios: - `UnsafeMove()` - ~1.5x faster than `Move()` -- `UnsafePushNotationMove()` - ~1.1x faster than `PushNotationMove()` +- `UnsafeMoveText()` - ~1.1x faster than `MoveText()` **API Consistency**: Refactored move methods for clear validation behavior and consistent performance options across all move APIs. @@ -46,11 +86,8 @@ open-source community and allowing for faster development. ## Disclaimer -**Breaking Changes**: This package is under the `/v2` namespace to signify that it might not be backward compatible with -the original package. -While some parts might work as plug-and-play, others might require changes. -Unfortunately, I do not plan to maintain a breaking change list at this time, but I expect in-code comments and the -compiler/linter to assist with migration. +**Breaking Changes**: v3 is a major release with API changes that are not backward compatible with v2. See the +[MIGRATION.md](MIGRATION.md) guide for a detailed list of breaking changes and how to update your code. **Maintenance**: This package is primarily maintained for my current work and projects. It is shared as a respect for the original work and to contribute to the community. My main focus is: @@ -85,7 +122,7 @@ If you have ideas or want to help make this package more robust and widely usabl **chess** can be installed using "go get". ```bash -go get -u github.com/corentings/chess/v2 +go get -u github.com/corentings/chess/v3 ``` ## Usage @@ -99,7 +136,7 @@ import ( "fmt" "math/rand" - "github.com/corentings/chess/v2" + "github.com/corentings/chess/v3" ) func main() { @@ -109,7 +146,7 @@ func main() { // select a random move moves := game.ValidMoves() move := moves[rand.Intn(len(moves))] - if err := game.Move(&move, nil); err != nil { + if err := game.Move(move, nil); err != nil { panic(err) // Should not happen with valid moves } } @@ -146,8 +183,8 @@ import ( "fmt" "time" - "github.com/corentings/chess/v2" - "github.com/corentings/chess/v2/uci" + "github.com/corentings/chess/v3" + "github.com/corentings/chess/v3/uci" ) func main() { @@ -158,7 +195,7 @@ func main() { } defer eng.Close() // initialize uci with new game - if err := eng.Run(uci.CmdUCI, uci.CmdIsReady, uci.CmdUCINewGame); err != nil { + if err := eng.Run(uci.CmdUCI{}, uci.CmdIsReady{}, uci.CmdUCINewGame{}); err != nil { panic(err) } // have stockfish play speed chess against itself (10 msec per move) @@ -194,7 +231,7 @@ The library offers two move execution methods to balance safety and performance: ```go game := chess.NewGame() moves := game.ValidMoves() -err := game.Move(&moves[0], nil) +err := game.Move(moves[0], nil) if err != nil { // Handle invalid move error } @@ -206,28 +243,28 @@ if err != nil { game := chess.NewGame() moves := game.ValidMoves() // Only use when you're certain the move is valid -err := game.UnsafeMove(&moves[0], nil) +err := game.UnsafeMove(moves[0], nil) if err != nil { // Handle error (should not occur with valid moves) } ``` -**PushNotationMove()** - Validates moves using any notation (recommended for general use): +**MoveText()** - Validates moves using any notation (recommended for general use): ```go game := chess.NewGame() -err := game.PushNotationMove("e4", chess.AlgebraicNotation{}, nil) +err := game.MoveText("e4", chess.SAN(), nil) if err != nil { // Handle invalid move or notation error } ``` -**UnsafePushNotationMove()** - High-performance notation parsing without move validation: +**UnsafeMoveText()** - High-performance notation parsing without move validation: ```go game := chess.NewGame() // Only use when you're certain the move is valid -err := game.UnsafePushNotationMove("e4", chess.AlgebraicNotation{}, nil) +err := game.UnsafeMoveText("e2e4", chess.UCI(), nil) if err != nil { // Handle notation parsing error (should not occur with valid notation) } @@ -235,7 +272,7 @@ if err != nil { > **Performance Note**: > - `UnsafeMove()` provides ~1.5x performance improvement over `Move()` by skipping validation -> - `UnsafePushNotationMove()` provides ~1.1x performance improvement over `PushNotationMove()` by skipping move +> - `UnsafeMoveText()` provides ~1.1x performance improvement over `MoveText()` by skipping move validation > - Use unsafe variants only when moves are pre-validated or known to be legal @@ -246,17 +283,17 @@ Valid moves generated from the game's current position: ```go game := chess.NewGame() moves := game.ValidMoves() -game.Move(&moves[0], nil) +game.Move(moves[0], nil) fmt.Println(moves[0]) // b1a3 ``` -#### Parse Notation +#### Parse Move Text -PushNotationMove method accepts string input using any supported notation: +MoveText accepts move text using an explicit codec: ```go game := chess.NewGame() -if err := game.PushNotationMove("e4", chess.AlgebraicNotation{}, nil); err != nil { +if err := game.MoveText("e4", chess.SAN(), nil); err != nil { // handle error } ``` @@ -273,7 +310,7 @@ game := chess.NewGame() validMoves := game.ValidMoves() if len(validMoves) > 0 { // This will succeed - move is known to be valid -if err := game.Move(&validMoves[0], nil); err != nil { +if err := game.Move(validMoves[0], nil); err != nil { fmt.Println("Move failed:", err) } else { fmt.Println("Move succeeded") @@ -281,14 +318,14 @@ fmt.Println("Move succeeded") } // Using notation parsing with validation -if err := game.PushNotationMove("e4", chess.AlgebraicNotation{}, nil); err != nil { +if err := game.MoveText("e4", chess.SAN(), nil); err != nil { fmt.Println("Move failed:", err) } else { fmt.Println("e4 move succeeded") } // Invalid notation will be caught -if err := game.PushNotationMove("e5", chess.AlgebraicNotation{}, nil); err != nil { +if err := game.MoveText("e5", chess.SAN(), nil); err != nil { fmt.Println("Move failed:", err) // Output: Move failed: [invalid move error] } @@ -301,13 +338,13 @@ game := chess.NewGame() // Option 1: Using Move structs directly (~1.5x faster) validMoves := game.ValidMoves() -selectedMove := &validMoves[0] // We know this is valid +selectedMove := validMoves[0] // We know this is valid if err := game.UnsafeMove(selectedMove, nil); err != nil { panic(err) // Should not happen with pre-validated moves } // Option 2: Using notation (~1.1x faster) -if err := game.UnsafePushNotationMove("e4", chess.AlgebraicNotation{}, nil); err != nil { +if err := game.UnsafeMoveText("e4", chess.SAN(), nil); err != nil { panic(err) // Should not happen with valid notation/moves } ``` @@ -323,10 +360,10 @@ Black wins by checkmate (Fool's Mate): ```go game := chess.NewGame() -game.PushNotationMove("f3", chess.AlgebraicNotation{}, nil) -game.PushNotationMove("e6", chess.AlgebraicNotation{}, nil) -game.PushNotationMove("g4", chess.AlgebraicNotation{}, nil) -game.PushNotationMove("Qh4", chess.AlgebraicNotation{}, nil) +game.MoveText("f3", chess.SAN(), nil) +game.MoveText("e6", chess.SAN(), nil) +game.MoveText("g4", chess.SAN(), nil) +game.MoveText("Qh4", chess.SAN(), nil) fmt.Println(game.Outcome()) // 0-1 fmt.Println(game.Method()) // Checkmate /* @@ -350,7 +387,7 @@ Black king has no safe move: fenStr := "k1K5/8/8/8/8/8/8/1Q6 w - - 0 1" fen, _ := chess.FEN(fenStr) game := chess.NewGame(fen) -game.PushNotationMove("Qb6", chess.AlgebraicNotation{}, nil) +game.MoveText("Qb6", chess.SAN(), nil) fmt.Println(game.Outcome()) // 1/2-1/2 fmt.Println(game.Method()) // Stalemate /* @@ -372,8 +409,10 @@ Black resigns and white wins: ```go game := chess.NewGame() -game.PushNotationMove("f3", chess.AlgebraicNotation{}, nil) -game.Resign(chess.Black) +game.MoveText("f3", chess.SAN(), nil) +if err := game.Resign(chess.Black); err != nil { + panic(err) +} fmt.Println(game.Outcome()) // 1-0 fmt.Println(game.Method()) // Resignation ``` @@ -399,7 +438,7 @@ until Fivefold Repetition. game := chess.NewGame() moves := []string{"Nf3", "Nf6", "Ng1", "Ng8", "Nf3", "Nf6", "Ng1", "Ng8"} for _, m := range moves { -game.PushNotationMove(m, chess.AlgebraicNotation{}, nil) +game.MoveText(m, chess.SAN(), nil) } fmt.Println(game.EligibleDraws()) // [DrawOffer ThreefoldRepetition] ``` @@ -418,7 +457,7 @@ moves := []string{ "Nf3", "Nf6", "Ng1", "Ng8", } for _, m := range moves { -game.PushNotationMove(m, chess.AlgebraicNotation{}, nil) +game.MoveText(m, chess.SAN(), nil) } fmt.Println(game.Outcome()) // 1/2-1/2 fmt.Println(game.Method()) // FivefoldRepetition @@ -446,7 +485,7 @@ checkmate. ```go fen, _ := chess.FEN("2r3k1/1q1nbppp/r3p3/3pP3/pPpP4/P1Q2N2/2RN1PPP/2R4K b - b3 149 23") game := chess.NewGame(fen) -game.PushNotationMove("Kf8", chess.AlgebraicNotation{}, nil) +game.MoveText("Kf8", chess.SAN(), nil) fmt.Println(game.Outcome()) // 1/2-1/2 fmt.Println(game.Method()) // SeventyFiveMoveRule ``` @@ -509,8 +548,8 @@ Moves and tag pairs added to the PGN output: ```go game := chess.NewGame() game.AddTagPair("Event", "F/S Return Match") -game.PushNotationMove("e4", chess.AlgebraicNotation{}, nil) -game.PushNotationMove("e5", chess.AlgebraicNotation{}, nil) +game.MoveText("e4", chess.SAN(), nil) +game.MoveText("e5", chess.SAN(), nil) fmt.Println(game) /* [Event "F/S Return Match"] @@ -522,14 +561,14 @@ fmt.Println(game) #### PGN comment annotations Parsed PGN comments preserve comment block boundaries, command annotation order, and duplicate command annotations. Use -`Move.CommentBlocks()` when an importer needs structured access to each `{...}` block and the ordered text or command +`MoveNode.CommentBlocks()` when an importer needs structured access to each `{...}` block and the ordered text or command items inside it. The returned blocks are defensive copies. ```go game := chess.NewGame(pgn) -move := game.Moves()[0] +node := game.MoveTree().MainLine()[0] -for _, block := range move.CommentBlocks() { +for _, block := range node.CommentBlocks() { for _, item := range block.Items { switch item.Kind { case chess.CommentText: @@ -541,32 +580,58 @@ for _, block := range move.CommentBlocks() { } ``` -The legacy helpers `Move.Comments()`, `Move.GetCommand()`, `Move.SetCommand()`, `Move.SetComment()`, and -`Move.AddComment()` remain available for callers that only need a flattened text comment or single command value. +The helpers `MoveNode.Comments()`, `MoveNode.GetCommand()`, `MoveNode.SetCommand()`, `MoveNode.SetComment()`, and +`MoveNode.AddComment()` remain available for callers that only need a flattened text comment or single command value. #### Scan PGN -For parsing large PGN database files use Scanner: +For parsing large PGN database files, use `PGNGames` (Go 1.23+ iterator): ```go f, err := os.Open("lichess_db_standard_rated_2013-01.pgn") if err != nil { -panic(err) + panic(err) } defer f.Close() -scanner := chess.NewScanner(f) -// Read all games -for scanner.HasNext() { -game, err := scanner.ParseNext() +for game, err := range chess.PGNGames(f) { + if err != nil { + log.Fatal("Failed to parse game: %v", err) + } + fmt.Println(game.GetTagPair("Site")) + // Output &{Site https://lichess.org/8jb5kiqw} +} +``` + +Or use `PGNDecoder` directly for index/offset access: + +```go +f, err := os.Open("lichess_db_standard_rated_2013-01.pgn") if err != nil { -log.Fatal("Failed to parse game: %v", err) + panic(err) } -fmt.Println(game.GetTagPair("Site")) -// Output &{Site https://lichess.org/8jb5kiqw} +defer f.Close() + +dec := chess.NewPGNDecoder(f) +for { + game, err := dec.Decode() + if err == io.EOF { + break + } + if err != nil { + log.Fatal("Failed to parse game: %v", err) + } + fmt.Println(game.GetTagPair("Site")) } ``` +`PGNDecoder` fully decodes each record into a `Game`, including move tree +positions, SAN resolution, checks, castling, promotions, en passant, comments, +NAGs, and tag pairs. In v3.0.0-beta.2 this path was tuned for large PGN +imports: SAN moves are resolved from direct candidate origins, and internal +position snapshots avoid a separate heap-allocated board copy while public +defensive-copy APIs remain unchanged. + #### Scan PGN expanding all variations To expand every variation into a distinct Game: @@ -574,19 +639,16 @@ To expand every variation into a distinct Game: ```go f, err := os.Open("lichess_db_standard_rated_2013-01.pgn") if err != nil { -panic(err) + panic(err) } defer f.Close() -scanner := chess.NewScanner(f, chess.WithExpandVariations()) -// Read all games -for scanner.HasNext() { -game, err := scanner.ParseNext() -if err != nil { -log.Fatal("Failed to parse game: %v", err) -} -fmt.Println(game.GetTagPair("Site")) -// Output &{Site https://lichess.org/8jb5kiqw} +for game, err := range chess.PGNGames(f, chess.WithPGNExpandVariations()) { + if err != nil { + log.Fatal("Failed to parse game: %v", err) + } + fmt.Println(game.GetTagPair("Site")) + // Output &{Site https://lichess.org/8jb5kiqw} } ``` @@ -618,10 +680,10 @@ pos := game.Position() fmt.Println(pos.String()) // rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 ``` -### Notations +### Move Text Codecs [Chess Notation](https://en.wikipedia.org/wiki/Chess_notation) define how moves are encoded in a serialized format. -Chess uses a notation when converting to and from PGN and for accepting move text. +Chess uses move text codecs when converting to and from PGN and for accepting move text. #### Algebraic Notation @@ -630,23 +692,23 @@ official chess notation used by FIDE. Examples: e2, e5, O-O (short castling), e8 ```go game := chess.NewGame() -game.PushNotationMove("e4", chess.AlgebraicNotation{}, nil) -game.PushNotationMove("e5", chess.AlgebraicNotation{}, nil) +game.MoveText("e4", chess.SAN(), nil) +game.MoveText("e5", chess.SAN(), nil) fmt.Println(game) // 1.e4 e5 * ``` #### Long Algebraic Notation [Long Algebraic Notation](https://en.wikipedia.org/wiki/Algebraic_notation_(chess)#Long_algebraic_notation) -LongAlgebraicNotation is a more beginner friendly alternative to algebraic notation, where the origin of the piece is +LongAlgebraic() is a more beginner friendly alternative to algebraic notation, where the origin of the piece is visible as well as the destination. Examples: Rd1xd8+, Ng8f6. ```go game := chess.NewGame() -game.PushNotationMove("f2f3", chess.LongAlgebraicNotation{}, nil) -game.PushNotationMove("e7e5", chess.LongAlgebraicNotation{}, nil) -game.PushNotationMove("g2g4", chess.LongAlgebraicNotation{}, nil) -game.PushNotationMove("Qd8h4", chess.LongAlgebraicNotation{}, nil) +game.MoveText("f2f3", chess.LongAlgebraic(), nil) +game.MoveText("e7e5", chess.LongAlgebraic(), nil) +game.MoveText("g2g4", chess.LongAlgebraic(), nil) +game.MoveText("Qd8h4", chess.LongAlgebraic(), nil) fmt.Println(game) // 1.f2f3 e7e5 2.g2g4 Qd8h4# 0-1 ``` @@ -657,9 +719,9 @@ Interface notation. Examples: e2e4, e7e5, e1g1 (white short castling), e7e8q (fo ```go game := chess.NewGame() -game.PushNotationMove("e2e4", chess.UCINotation{}, nil) -game.PushNotationMove("e7e5", chess.UCINotation{}, nil) -fmt.Println(game) // 1.e2e4 e7e5 * +game.MoveText("e2e4", chess.UCI(), nil) +game.MoveText("e7e5", chess.UCI(), nil) +fmt.Println(game) // 1.e4 e5 * ``` #### Text Representation @@ -684,7 +746,8 @@ fmt.Println(game.Position().Board().Draw()) ### Moves -Moves is a convenient API for accessing aligned positions, moves, and comments. Moves is useful when trying to understand detailed information about a game. Below is an +MoveList is a convenient API for accessing the main-line moves and their +comments. MoveList is useful when iterating the moves of a game. Below is an example showing how to see which side castled first. ```go @@ -694,7 +757,7 @@ import ( "fmt" "os" - "github.com/corentings/chess/v2" + "github.com/corentings/chess/v3" ) func main() { @@ -709,11 +772,16 @@ func main() { } game := chess.NewGame(pgn) color := chess.NoColor - for _, mh := range game.Moves() { - if mh.HasTag(chess.KingSideCastle) || mh.HasTag(chess.QueenSideCastle) { - color = mh.Position().Turn() + // Replay positions alongside the moves via the tree's cursor. + tree := game.MoveTree() + tree.Reset() + for _, entry := range game.MoveList() { + preTurn := tree.Peek().Turn() + if entry.Move.HasTag(chess.KingSideCastle) || entry.Move.HasTag(chess.QueenSideCastle) { + color = preTurn break } + tree.GoForward() } switch color { case chess.White: @@ -726,6 +794,175 @@ func main() { } ``` +## Perft + +[Perft](https://www.chessprogramming.org/Perft) (performance test) is the +standard correctness and performance benchmark for a chess move generator: it +counts every legal move sequence of a given length reachable from a starting +position. This package exposes Perft on `*Position`; the traversal uses the +same legality rules that govern normal play while applying moves through an +internal make/unmake path for performance. + +### Bulk node count + +```go +package main + +import ( + "fmt" + + "github.com/corentings/chess/v3" +) + +func main() { + pos := chess.StartingPosition() + fmt.Println("startpos d5:", pos.Perft(5)) // 4 865 609 + fmt.Println("startpos d6:", pos.Perft(6)) // 119 060 324 +} +``` + +A depth of 0 returns 1 (the position itself counts as a leaf). A position with +no legal moves (checkmate or stalemate) returns 0 for any depth greater than 0. + +### Per-move breakdown (`Divide`) + +`Divide` returns the per-root-move Perft breakdown as a map from each legal +move to its leaf count. It is the standard way to localize a divergence when +two move generators disagree at a given depth. + +```go +package main + +import ( + "fmt" + "sort" + + "github.com/corentings/chess/v3" +) + +func main() { + pos := chess.StartingPosition() + results := pos.Divide(1) + + keys := make([]chess.Move, 0, len(results)) + for m := range results { + keys = append(keys, m) + } + sort.Slice(keys, func(i, j int) bool { + return keys[i].String() < keys[j].String() + }) + for _, m := range keys { + fmt.Printf("%s: %d\n", m, results[m]) + } +} +``` + +Map iteration order is unspecified; sort by `Move.String()` for a stable +display. Move strings are long-algebraic (`s1s2` plus a promotion suffix) and +are intended for debugging, not for chess notation. + +### Canonical positions + +The package's Perft tests verify six canonical positions from +[chessprogramming.org/Perft_Results](https://www.chessprogramming.org/Perft_Results) +through depth 4–6. For a side-by-side performance comparison against another +Go chess library, see [`benchcmp/perft/`](./benchcmp/perft/). + +## Move Tree + +A `Game` owns a `MoveTree` containing the moves that have been played. The root +is a synthetic position node before any move has been played. Each non-root +`MoveNode` holds the `Move` it represents, its `Position` after the move, its +parent and ordered continuations, plus comments, NAGs, and `[%clk ...]`-style +command annotations. The first continuation is the main line; later +continuations are variations. + +Use `Game.Move`, `Game.UnsafeMove`, `Game.MoveText`, or +`Game.UnsafeMoveText` to play moves on the active cursor. Those methods keep +game legality, terminal outcome guards, and result evaluation in sync with the +tree. `MoveTree` exposes traversal, cursor navigation, and variation editing; +it does not expose a public API for advancing the active game state directly. + +The older names `Game.PushMove`, `Game.PushMoveText`, and +`Game.UnsafePushMoveText` are deprecated but remain functional for this major +version. + +```go +package main + +import ( + "fmt" + + "github.com/corentings/chess/v3" +) + +func main() { + g := chess.NewGame() + g.MoveText("e4", chess.SAN(), nil) + g.MoveText("e5", chess.SAN(), nil) + + // Walk the main line. + for _, n := range g.MoveTree().MainLine() { + fmt.Printf("%s ", n.Move()) + } + fmt.Println() +} +``` + +```go +package main + +import ( + "fmt" + "strings" + + "github.com/corentings/chess/v3" +) + +func main() { + g, _ := chess.ParsePGN(strings.NewReader( + `[Result "*"] 1. e4 e5 (1... c5 {Sicilian}) 2. Nf3 *`, + )) + + tree := g.MoveTree() + e4 := tree.MainChild(tree.Root()) // first move of the main line + + // Walk the main line by following the main continuation at each node. + fmt.Print("main: ") + for n := e4; n != nil; n = tree.MainChild(n) { + fmt.Printf("%s ", n.Move()) + } + fmt.Println() + + // Enumerate sideline variations at e4. + fmt.Print("variations at e4: ") + for _, v := range tree.Variations(e4) { + fmt.Printf("%s ", v.Move()) + } + fmt.Println() +} +``` + +Useful APIs over the tree: + +- `Game.MoveTree() *MoveTree` — returns the game tree and active cursor. +- `MoveTree.Root() *MoveNode` — root position node. +- `MoveTree.Current() *MoveNode` — active cursor node. +- `MoveTree.MainLine() []*MoveNode` — main-line nodes, excluding the root. +- `MoveTree.MainChild(node *MoveNode) *MoveNode` — main continuation. +- `MoveTree.Continuations(node *MoveNode) []*MoveNode` — all continuations. +- `MoveTree.Variations(node *MoveNode) []*MoveNode` — sideline continuations. +- `MoveTree.AddVariation(parent *MoveNode, move Move) (*MoveNode, error)` — + validate and append a sideline. +- `MoveTree.GoBack()`, `MoveTree.GoForward()`, and + `MoveTree.NavigateToMainLine()` — move the active cursor without changing + game outcome metadata. +- `node.Move()`, `node.Position()`, `node.Comments()`, `node.NAG()`, + `node.Children()`, and `node.Parent()` — per-node data. + +Perft does not store its results in the game tree; it walks a temporary move +tree internally, so it does not affect the `MoveTree` you see from `Game`. + ## Performance Chess has been performance tuned, using [pprof](https://golang.org/pkg/runtime/pprof/), with the goal of being fast @@ -740,13 +977,22 @@ The benchmarks can be run with the following command: go test -bench=. ``` -Results from the baseline 2015 MBP: +Results vary by hardware. For comparative benchmarking use +[`benchstat`](https://pkg.go.dev/golang.org/x/perf/cmd/benchstat): ``` -BenchmarkBitboardReverse-4 2000000000 1.01 ns/op -BenchmarkStalemateStatus-4 500000 3116 ns/op -BenchmarkInvalidStalemateStatus-4 500000 2290 ns/op -BenchmarkPositionHash-4 1000000 1864 ns/op -BenchmarkValidMoves-4 100000 13445 ns/op -BenchmarkPGN-4 300 5549192 ns/op +go test -bench=. -count=10 > new.txt +benchstat base.txt new.txt ``` + +See [CONTRIBUTING.md](./CONTRIBUTING.md) for the full benchmark workflow. + +The v3.0.0-beta.2 PGN decode work was measured with: + +``` +go test -run '^$' -bench '^BenchmarkPGN_FullGameDecode_(BigBig|Big|CompleteGameDetails|ExpandVariations)$' -benchmem -count=6 ./ +``` + +On the project `big_big.pgn` fixture, `BenchmarkPGN_FullGameDecode_BigBig` +improved from roughly `1.48s/op` and `6.62M allocs/op` to roughly `0.91s/op` +and `5.55M allocs/op` on the maintainer benchmark machine. diff --git a/attacks.go b/attacks.go new file mode 100644 index 00000000..4353a22b --- /dev/null +++ b/attacks.go @@ -0,0 +1,251 @@ +package chess + +import "math/bits" + +func pawnCheckers(board *Board, kingSq Square, attacker Color) bitboard { + pawns := board.bbForPiece(NewPiece(Pawn, attacker)) + var checkers bitboard + for pawnBits := pawns; pawnBits != 0; pawnBits &= pawnBits - 1 { + pawnSq := squareFromBit(pawnBits & -pawnBits) + if pawnAttacks(attacker, pawnSq)&bbForSquare(kingSq) != 0 { + checkers |= bbForSquare(pawnSq) + } + } + return checkers +} + +func pawnAttacks(c Color, sq Square) bitboard { + bb := bbForSquare(sq) + if c == White { + return ((bb & ^bbFileH & ^bbRank8) >> 9) | ((bb & ^bbFileA & ^bbRank8) >> 7) + } + return ((bb & ^bbFileH & ^bbRank1) << 7) | ((bb & ^bbFileA & ^bbRank1) << 9) +} + +func pinnedRayForPiece(pos *Position, s1 Square) bitboard { + kingSq := pos.board.kingSquare(pos.turn) + if kingSq == NoSquare || alignedMasks[kingSq]&bbForSquare(s1) == 0 { + return 0 + } + fileStep := int(rayFileSteps[kingSq][s1]) + rankStep := int(rayRankSteps[kingSq][s1]) + if fileStep == 0 && rankStep == 0 { + return 0 + } + if betweenMasks[kingSq][s1]&^pos.board.emptySqs != 0 { + return 0 + } + diagonal := rayDiagonals[kingSq][s1] + file := int(s1.File()) + fileStep + rank := int(s1.Rank()) + rankStep + for file >= 0 && file < numOfSquaresInRow && rank >= 0 && rank < numOfSquaresInRow { + sq := NewSquare(File(file), Rank(rank)) + p := pos.board.Piece(sq) + if p != NoPiece { + if p.Color() != pos.turn.Other() || !piecePinsAlong(p.Type(), diagonal) { + return 0 + } + return betweenMasks[kingSq][sq] | bbForSquare(sq) + } + file += fileStep + rank += rankStep + } + return 0 +} + +func sliderBitboards(board *Board, c Color) (bitboard, bitboard, bitboard) { + if c == White { + return board.bbWhiteQueen, board.bbWhiteRook, board.bbWhiteBishop + } + return board.bbBlackQueen, board.bbBlackRook, board.bbBlackBishop +} + +func squaresAligned(a Square, b Square) bool { + fileDelta := int(a.File()) - int(b.File()) + if fileDelta < 0 { + fileDelta = -fileDelta + } + rankDelta := int(a.Rank()) - int(b.Rank()) + if rankDelta < 0 { + rankDelta = -rankDelta + } + return a.File() == b.File() || a.Rank() == b.Rank() || fileDelta == rankDelta +} + +// checkState returns whether the side to move is in check and a bitboard of +// the pieces giving check. It reuses the same attack-set walk as isInCheck so +// the two cannot drift. +func checkState(pos *Position) (bool, bitboard) { + kingSq := pos.board.kingSquare(pos.Turn()) + // king should only be missing in tests / examples + if kingSq == NoSquare { + return false, 0 + } + attacker := pos.Turn().Other() + board := &pos.board + occ := ^board.emptySqs + + // Hot-path filter: if no attacker occupies a square that a queen or knight + // could attack the king from, no piece gives check. King and pawn attacks + // are subsets of queen-move squares, so this filter is sound. + var attackerSqs bitboard + if attacker == White { + attackerSqs = board.whiteSqs + } else { + attackerSqs = board.blackSqs + } + diagAttacks := diaAttack(occ, kingSq) + orthogonalAttacks := hvAttack(occ, kingSq) + if ((diagAttacks|orthogonalAttacks)&attackerSqs)|(bbKnightMoves[kingSq]&attackerSqs) == 0 { + return false, 0 + } + + queenBB, rookBB, bishopBB := sliderBitboards(board, attacker) + + checkers := (orthogonalAttacks & (queenBB | rookBB)) | + (diagAttacks & (queenBB | bishopBB)) | + (bbKnightMoves[kingSq] & board.bbForPiece(NewPiece(Knight, attacker))) | + (bbKingMoves[kingSq] & board.bbForPiece(NewPiece(King, attacker))) | + pawnCheckers(board, kingSq, attacker) + + return checkers != 0, checkers +} + +// bitboardSquares returns the occupied squares of bb as a slice in +// most-significant-bit-first order. +func bitboardSquares(bb bitboard) []Square { + n := bits.OnesCount64(uint64(bb)) + if n == 0 { + return nil + } + sqs := make([]Square, 0, n) + for bb != 0 { + lsb := bb & -bb + sqs = append(sqs, squareFromBit(lsb)) + bb &^= lsb + } + return sqs +} + +// isInCheck returns true if the side to move is in check in the given position. +func isInCheck(pos *Position) bool { + inCheck, _ := checkState(pos) + return inCheck +} + +// isSquareAttackedBy returns true if the given square is attacked by the specified color. +// This is a board-level operation that does not require a full Position. +// +//nolint:mnd // this is a formula to determine if a square is attacked +func isSquareAttackedBy(board *Board, sq Square, attacker Color) bool { + occ := ^board.emptySqs + + // hot path check to see if attack vector is possible + s2BB := board.blackSqs + if attacker == White { + s2BB = board.whiteSqs + } + diagAttacks := diaAttack(occ, sq) + orthogonalAttacks := hvAttack(occ, sq) + if ((diagAttacks|orthogonalAttacks)&s2BB)|(bbKnightMoves[sq]&s2BB) == 0 { + return false + } + + // check queen attack vector + queenBB := board.bbForPiece(NewPiece(Queen, attacker)) + bb := (diagAttacks | orthogonalAttacks) & queenBB + if bb != 0 { + return true + } + // check rook attack vector + rookBB := board.bbForPiece(NewPiece(Rook, attacker)) + bb = orthogonalAttacks & rookBB + if bb != 0 { + return true + } + // check bishop attack vector + bishopBB := board.bbForPiece(NewPiece(Bishop, attacker)) + bb = diagAttacks & bishopBB + if bb != 0 { + return true + } + // check knight attack vector + knightBB := board.bbForPiece(NewPiece(Knight, attacker)) + bb = bbKnightMoves[sq] & knightBB + if bb != 0 { + return true + } + // check pawn attack vector + if attacker == Black { + capRight := (board.bbBlackPawn & ^bbFileH & ^bbRank1) << 7 + capLeft := (board.bbBlackPawn & ^bbFileA & ^bbRank1) << 9 + bb = (capRight | capLeft) & bbForSquare(sq) + if bb != 0 { + return true + } + } else { + capRight := (board.bbWhitePawn & ^bbFileH & ^bbRank8) >> 9 + capLeft := (board.bbWhitePawn & ^bbFileA & ^bbRank8) >> 7 + bb = (capRight | capLeft) & bbForSquare(sq) + if bb != 0 { + return true + } + } + // check king attack vector + kingBB := board.bbForPiece(NewPiece(King, attacker)) + bb = bbKingMoves[sq] & kingBB + return bb != 0 +} + +// squaresAreAttacked returns true if the opponent attacks any of the given squares +// +// in the given position. +// +// The function checks attacks from: +// - Sliding pieces (queen, rook, bishop) +// - Knights +// - Pawns +// - King +func squaresAreAttacked(pos *Position, sqs ...Square) bool { + otherColor := pos.Turn().Other() + for _, sq := range sqs { + if isSquareAttackedBy(&pos.board, sq, otherColor) { + return true + } + } + return false +} + +// KnightAttacks returns the set of squares a knight on sq attacks. +func KnightAttacks(sq Square) Bitboard { + return Bitboard(bbKnightMoves[sq]) +} + +// KingAttacks returns the set of squares a king on sq attacks. +func KingAttacks(sq Square) Bitboard { + return Bitboard(bbKingMoves[sq]) +} + +// PawnAttacks returns the set of squares a pawn of color c on sq attacks. +func PawnAttacks(sq Square, c Color) Bitboard { + return Bitboard(pawnAttacks(c, sq)) +} + +// BishopAttacks returns the set of squares a bishop on sq attacks given the +// supplied occupied squares. +func BishopAttacks(sq Square, occupied Bitboard) Bitboard { + return Bitboard(diaAttack(bitboard(occupied), sq)) +} + +// RookAttacks returns the set of squares a rook on sq attacks given the +// supplied occupied squares. +func RookAttacks(sq Square, occupied Bitboard) Bitboard { + return Bitboard(hvAttack(bitboard(occupied), sq)) +} + +// QueenAttacks returns the set of squares a queen on sq attacks given the +// supplied occupied squares. It is the union of the bishop and rook attacks. +func QueenAttacks(sq Square, occupied Bitboard) Bitboard { + occ := bitboard(occupied) + return Bitboard(diaAttack(occ, sq) | hvAttack(occ, sq)) +} diff --git a/attacks_public_test.go b/attacks_public_test.go new file mode 100644 index 00000000..3b62e0d1 --- /dev/null +++ b/attacks_public_test.go @@ -0,0 +1,47 @@ +package chess + +import "testing" + +func TestPublicAttacks(t *testing.T) { + // Knight on e4 attacks d6, f6, g5, g3, f2, d2, c3, c5. + knight := KnightAttacks(E4) + for _, sq := range []Square{D6, F6, G5, G3, F2, D2, C3, C5} { + if !Bitboard(bbForSquare(sq)).Intersects(Bitboard(knight)) { + t.Fatalf("expected knight on E4 to attack %s", sq) + } + } + if knight.Popcount() != 8 { + t.Fatalf("expected 8 knight attacks, got %d", knight.Popcount()) + } + + // King on e4 attacks 8 surrounding squares. + king := KingAttacks(E4) + if king.Popcount() != 8 { + t.Fatalf("expected 8 king attacks, got %d", king.Popcount()) + } + + // White pawn on e4 attacks d5 and f5. + wp := PawnAttacks(E4, White) + if wp.Popcount() != 2 { + t.Fatalf("expected 2 white pawn attacks, got %d", wp.Popcount()) + } + if !Bitboard(bbForSquare(D5)).Intersects(Bitboard(wp)) || !Bitboard(bbForSquare(F5)).Intersects(Bitboard(wp)) { + t.Fatalf("white pawn on E4 should attack D5 and F5, got %s", wp.Draw()) + } + + // Black pawn on e4 attacks d3 and f3. + bp := PawnAttacks(E4, Black) + if bp.Popcount() != 2 { + t.Fatalf("expected 2 black pawn attacks, got %d", bp.Popcount()) + } + if !Bitboard(bbForSquare(D3)).Intersects(Bitboard(bp)) || !Bitboard(bbForSquare(F3)).Intersects(Bitboard(bp)) { + t.Fatalf("black pawn on E4 should attack D3 and F3, got %s", bp.Draw()) + } + + // Rook on d4 with starting occupancy: attacks along rank 4 and file d. + occ := StartingPosition().Board().Occupied() + rook := RookAttacks(D4, occ) + if rook.IsEmpty() { + t.Fatal("rook on d4 should attack squares") + } +} diff --git a/bitboard.go b/bitboard.go index 6e6370f4..dedda981 100644 --- a/bitboard.go +++ b/bitboard.go @@ -93,21 +93,23 @@ func (b bitboard) String() string { // Draw returns visual representation of the bitboard useful for debugging. func (b bitboard) Draw() string { - s := "\n A B C D E F G H\n" + var sb strings.Builder + sb.Grow(154) + sb.WriteString("\n A B C D E F G H\n") for r := 7; r >= 0; r-- { - s += Rank(r).String() + sb.WriteString(Rank(r).String()) for f := range numOfSquaresInRow { sq := NewSquare(File(f), Rank(r)) if b.Occupied(sq) { - s += "1" + sb.WriteByte('1') } else { - s += "0" + sb.WriteByte('0') } - s += " " + sb.WriteByte(' ') } - s += "\n" + sb.WriteByte('\n') } - return s + return sb.String() } // Reverse returns a new bitboard with the bit order reversed, which can be diff --git a/bitboard_public.go b/bitboard_public.go new file mode 100644 index 00000000..9cb22ef9 --- /dev/null +++ b/bitboard_public.go @@ -0,0 +1,144 @@ +package chess + +import ( + "math/bits" + "strconv" + "strings" +) + +// Bitboard is a public 64-bit set of squares. It is backed by a uint64 where +// the most significant bit represents A1 and the least significant bit +// represents H8, matching the internal bitboard layout. +type Bitboard uint64 + +// NewBitboardFromSquares returns a Bitboard with the given squares set. +func NewBitboardFromSquares(squares ...Square) Bitboard { + var bb Bitboard + for _, sq := range squares { + bb |= Bitboard(bbForSquare(sq)) + } + return bb +} + +// And returns the intersection of bb and other. +func (bb Bitboard) And(other Bitboard) Bitboard { + return bb & other +} + +// Or returns the union of bb and other. +func (bb Bitboard) Or(other Bitboard) Bitboard { + return bb | other +} + +// Xor returns the symmetric difference of bb and other. +func (bb Bitboard) Xor(other Bitboard) Bitboard { + return bb ^ other +} + +// Not returns the complement of bb (all 64 squares, flipped). +func (bb Bitboard) Not() Bitboard { + return ^bb +} + +// Subtract returns the squares in bb that are not in other. +func (bb Bitboard) Subtract(other Bitboard) Bitboard { + return bb &^ other +} + +// Intersects reports whether bb and other share at least one square. +func (bb Bitboard) Intersects(other Bitboard) bool { + return (bb & other) != 0 +} + +// IsEmpty reports whether bb contains no squares. +func (bb Bitboard) IsEmpty() bool { + return bb == 0 +} + +// Popcount returns the number of set squares. +func (bb Bitboard) Popcount() int { + return bits.OnesCount64(uint64(bb)) +} + +// FirstSquare returns the most significant set square. It panics if bb is empty. +func (bb Bitboard) FirstSquare() Square { + if bb == 0 { + panic("chess: FirstSquare called on empty Bitboard") + } + return squareFromBit(bitboard(bb)) +} + +// LastSquare returns the least significant set square. It panics if bb is empty. +func (bb Bitboard) LastSquare() Square { + if bb == 0 { + panic("chess: LastSquare called on empty Bitboard") + } + return Square(63 - bits.TrailingZeros64(uint64(bb))) +} + +// Squares yields every set square using Go 1.23's range-over-func pattern. +// +// Example: +// +// for sq := range bb.Squares { +// // process square +// } +func (bb Bitboard) Squares(yield func(Square) bool) { + for bb != 0 { + lsb := bb & -bb + if !yield(squareFromBit(bitboard(lsb))) { + return + } + bb &^= lsb + } +} + +// String returns a 64-character string of '1's and '0's starting with the most +// significant bit (A1). This matches the internal bitboard.String() format and +// round-trips unambiguously. +func (bb Bitboard) String() string { + s := strconv.FormatUint(uint64(bb), 2) + return strings.Repeat("0", numOfSquaresInBoard-len(s)) + s +} + +// Draw returns an 8x8 visual representation of the bitboard useful for debugging. +func (bb Bitboard) Draw() string { + var sb strings.Builder + sb.Grow(154) + sb.WriteString("\n A B C D E F G H\n") + for r := 7; r >= 0; r-- { + sb.WriteString(Rank(r).String()) + for f := range numOfSquaresInRow { + sq := NewSquare(File(f), Rank(r)) + if Bitboard(bbForSquare(sq))&bb != 0 { + sb.WriteByte('1') + } else { + sb.WriteByte('0') + } + sb.WriteByte(' ') + } + sb.WriteByte('\n') + } + return sb.String() +} + +// MarshalText implements encoding.TextMarshaler using the 64-character binary +// string representation. +func (bb Bitboard) MarshalText() ([]byte, error) { + return []byte(bb.String()), nil +} + +// UnmarshalText implements encoding.TextUnmarshaler from the 64-character +// binary string representation. +func (bb *Bitboard) UnmarshalText(text []byte) error { + s := string(text) + if len(s) != numOfSquaresInBoard { + return strconv.ErrRange + } + v, err := strconv.ParseUint(s, 2, 64) + if err != nil { + return err + } + *bb = Bitboard(v) + return nil +} diff --git a/bitboard_public_test.go b/bitboard_public_test.go new file mode 100644 index 00000000..f75ca455 --- /dev/null +++ b/bitboard_public_test.go @@ -0,0 +1,54 @@ +package chess + +import ( + "slices" + "testing" +) + +func TestBitboardFromSquares(t *testing.T) { + bb := NewBitboardFromSquares(E4, D4) + if bb.Popcount() != 2 { + t.Fatalf("expected popcount 2, got %d", bb.Popcount()) + } + var got []Square + for sq := range bb.Squares { + got = append(got, sq) + } + want := []Square{E4, D4} + if !slices.Equal(got, want) { + t.Fatalf("expected squares %v, got %v", want, got) + } +} + +func TestBitboardSetOps(t *testing.T) { + bb := NewBitboardFromSquares(E4, D4) + bb2 := NewBitboardFromSquares(D4, C4) + + if bb.And(bb2).Popcount() != 1 { + t.Fatal("expected intersection popcount 1") + } + if bb.Or(bb2).Popcount() != 3 { + t.Fatal("expected union popcount 3") + } + if bb.Subtract(bb2).Popcount() != 1 { + t.Fatal("expected subtract popcount 1") + } + if !bb.Intersects(bb2) { + t.Fatal("expected bb and bb2 to intersect") + } + if !NewBitboardFromSquares().IsEmpty() { + t.Fatal("expected empty bitboard") + } +} + +func TestBitboardStringRoundTrip(t *testing.T) { + bb := NewBitboardFromSquares(A1, H8) + s := bb.String() + var rt Bitboard + if err := rt.UnmarshalText([]byte(s)); err != nil { + t.Fatal(err) + } + if rt != bb { + t.Fatalf("round-trip failed: %v != %v", rt, bb) + } +} diff --git a/bitboard_test.go b/bitboard_test.go index f0ba4930..1b6b3820 100644 --- a/bitboard_test.go +++ b/bitboard_test.go @@ -96,7 +96,7 @@ func TestBitboardOccupied(t *testing.T) { } func BenchmarkBitboardReverse(b *testing.B) { - for i := 0; i < b.N; i++ { + for range b.N { u := uint64(9223372036854775807) bitboard(u).Reverse() } diff --git a/board.go b/board.go index 115b2341..aa352321 100644 --- a/board.go +++ b/board.go @@ -1,45 +1,11 @@ -/* -Package chess provides a chess engine implementation using bitboard representation for board state. - -The package uses a combination of bitboards for piece positions and convenience lookups, -allowing for efficient move generation and position analysis. - -Board Layout: - - 8 | r n b q k b n r - 7 | p p p p p p p p - 6 | - - - - - - - - - 5 | - - - - - - - - - 4 | - - - - - - - - - 3 | - - - - - - - - - 2 | P P P P P P P P - 1 | R N B Q K B N R - --------------- - A B C D E F G H - -Usage: - - // Create a new board with starting position - squares := map[Square]Piece{ - NewSquare(FileE, Rank1): WhiteKing, - NewSquare(FileD, Rank8): BlackQueen, - } - board := NewBoard(squares) - - // Check piece at square - piece := board.Piece(NewSquare(FileE, Rank1)) - - // Get all piece positions. - positions := board.SquareMap() -*/ - package chess import ( - "bytes" "encoding/binary" "errors" "fmt" + "math/bits" + "strings" ) // Board represents a chess board and its relationship between squares and pieces. @@ -58,17 +24,17 @@ type Board struct { bbBlackBishop bitboard bbBlackKnight bitboard bbBlackPawn bitboard - whiteSqs bitboard // all white pieces - blackSqs bitboard // all black pieces - emptySqs bitboard // all empty squares - whiteKingSq Square // cached white king square - blackKingSq Square // cached black king square + whiteSqs bitboard // all white pieces + blackSqs bitboard // all black pieces + emptySqs bitboard // all empty squares + whiteKingSq Square // cached white king square + blackKingSq Square // cached black king square mailbox [numOfSquaresInBoard]Piece // O(1) piece lookup per square } // kingSquare returns the cached king square for the given color. // Callers must ensure the board's convenience bitboards are up to date -// (i.e., calcConvienceBBs has been called after any mutation). +// (i.e., calcConvenienceBBs has been called after any mutation). func (b *Board) kingSquare(c Color) Square { if c == White { return b.whiteKingSq @@ -104,14 +70,14 @@ func NewBoard(m map[Square]Piece) (*Board, error) { return nil, err } } - b.calcConvienceBBs(nil) + b.calcConvenienceBBs(nil) return b, nil } // SquareMap returns a mapping of squares to pieces. // A square is only added to the map if it is occupied. func (b *Board) SquareMap() map[Square]Piece { - m := map[Square]Piece{} + m := make(map[Square]Piece, numOfSquaresInBoard) for sq := range numOfSquaresInBoard { p := b.Piece(Square(sq)) if p != NoPiece { @@ -144,7 +110,7 @@ const ( // For UpDown, pieces are mirrored across the horizontal center line. // For LeftRight, pieces are mirrored across the vertical center line. func (b *Board) Flip(fd FlipDirection) (*Board, error) { - m := map[Square]Piece{} + m := make(map[Square]Piece, numOfSquaresInBoard) for sq := range numOfSquaresInBoard { var mv Square switch fd { @@ -164,7 +130,7 @@ func (b *Board) Flip(fd FlipDirection) (*Board, error) { // Transpose flips the board over the A8 to H1 diagonal. func (b *Board) Transpose() (*Board, error) { - m := map[Square]Piece{} + m := make(map[Square]Piece, numOfSquaresInBoard) for sq := range numOfSquaresInBoard { file := File(7 - Square(sq).Rank()) rank := Rank(7 - Square(sq).File()) @@ -195,7 +161,7 @@ func (b *Board) Draw() string { // Draw2 returns visual representation of the board useful for debugging. // It is similar to Draw() except allows the caller to specify perspective -// and dark mode options +// and dark mode options. func (b *Board) Draw2(perspective Color, darkMode bool) string { if perspective == Black { return b.drawForBlack(darkMode) @@ -204,61 +170,64 @@ func (b *Board) Draw2(perspective Color, darkMode bool) string { return b.drawForWhite(darkMode) } -// drawForWhite returns visual representation of the board from white's perspective +// drawForWhite returns visual representation of the board from white's perspective. func (b *Board) drawForWhite(darkMode bool) string { - s := "\n A B C D E F G H\n" + var sb strings.Builder + sb.Grow(154) + sb.WriteString("\n A B C D E F G H\n") for r := 7; r >= 0; r-- { - s += Rank(r).String() + sb.WriteString(Rank(r).String()) for f := range numOfSquaresInRow { p := b.Piece(NewSquare(File(f), Rank(r))) - if p == NoPiece { - s += "-" - } else { - if darkMode { - s += p.DarkString() - } else { - s += p.String() - } + switch { + case p == NoPiece: + sb.WriteByte('-') + case darkMode: + sb.WriteString(p.DarkString()) + default: + sb.WriteString(p.String()) } - s += " " + sb.WriteByte(' ') } - s += "\n" + sb.WriteByte('\n') } - return s + return sb.String() } -// drawForBlack returns visual representation of the board from black's perspective +// drawForBlack returns visual representation of the board from black's perspective. func (b *Board) drawForBlack(darkMode bool) string { - s := "\n H G F E D C B A\n" - for r := 0; r <= 7; r++ { - s += Rank(r).String() + var sb strings.Builder + sb.Grow(154) + sb.WriteString("\n H G F E D C B A\n") + for r := range 8 { + sb.WriteString(Rank(r).String()) for f := numOfSquaresInRow - 1; f >= 0; f-- { p := b.Piece(NewSquare(File(f), Rank(r))) - if p == NoPiece { - s += "-" - } else { - if darkMode { - s += p.DarkString() - } else { - s += p.String() - } + switch { + case p == NoPiece: + sb.WriteByte('-') + case darkMode: + sb.WriteString(p.DarkString()) + default: + sb.WriteString(p.String()) } - s += " " + sb.WriteByte(' ') } - s += "\n" + sb.WriteByte('\n') } - return s + return sb.String() } // String implements the fmt.Stringer interface and returns // a string in the FEN board format: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR. func (b *Board) String() string { + return string(b.appendFEN(make([]byte, 0, 71))) +} + +func (b *Board) appendFEN(buf []byte) []byte { const maxRankValue = 7 const numOfFiles = 8 - // Use a buffer to build the string - buf := make([]byte, 0, 71) - // Buffer to count empty squares emptyCount := 0 @@ -296,8 +265,7 @@ func (b *Board) String() string { } } - // Convert to string once at the end - return string(buf) + return buf } // Piece returns the piece for the given square. @@ -306,6 +274,39 @@ func (b *Board) Piece(sq Square) Piece { return b.mailbox[sq] } +// White returns the squares occupied by white pieces. +func (b *Board) White() Bitboard { + return Bitboard(b.whiteSqs) +} + +// Black returns the squares occupied by black pieces. +func (b *Board) Black() Bitboard { + return Bitboard(b.blackSqs) +} + +// Occupied returns all occupied squares. +func (b *Board) Occupied() Bitboard { + return Bitboard(b.whiteSqs | b.blackSqs) +} + +// Empty returns all empty squares. +func (b *Board) Empty() Bitboard { + return Bitboard(b.emptySqs) +} + +// Color returns the squares occupied by pieces of the given color. +func (b *Board) Color(c Color) Bitboard { + if c == White { + return Bitboard(b.whiteSqs) + } + return Bitboard(b.blackSqs) +} + +// Pieces returns the squares occupied by pieces of the given type and color. +func (b *Board) Pieces(pt PieceType, c Color) Bitboard { + return Bitboard(b.bbForPiece(NewPiece(pt, c))) +} + // MarshalText implements the encoding.TextMarshaler interface and returns // a string in the FEN board format: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR. func (b *Board) MarshalText() ([]byte, error) { @@ -317,7 +318,7 @@ func (b *Board) MarshalText() ([]byte, error) { func (b *Board) UnmarshalText(text []byte) error { cp, err := fenBoard(string(text)) if err != nil { - return err + return fmt.Errorf("chess: unmarshal board FEN: %w", err) } *b = *cp return nil @@ -328,13 +329,15 @@ func (b *Board) UnmarshalText(text []byte) error { // in the following order: WhiteKing, WhiteQueen, WhiteRook, WhiteBishop, WhiteKnight // WhitePawn, BlackKing, BlackQueen, BlackRook, BlackBishop, BlackKnight, BlackPawn. func (b *Board) MarshalBinary() ([]byte, error) { - bbs := []bitboard{ + bbs := [...]bitboard{ b.bbWhiteKing, b.bbWhiteQueen, b.bbWhiteRook, b.bbWhiteBishop, b.bbWhiteKnight, b.bbWhitePawn, b.bbBlackKing, b.bbBlackQueen, b.bbBlackRook, b.bbBlackBishop, b.bbBlackKnight, b.bbBlackPawn, } - buf := new(bytes.Buffer) - err := binary.Write(buf, binary.BigEndian, bbs) - return buf.Bytes(), err + buf := make([]byte, 8*len(bbs)) + for i, bb := range bbs { + binary.BigEndian.PutUint64(buf[i*8:], uint64(bb)) + } + return buf, nil } // UnmarshalBinary implements the encoding.BinaryUnmarshaler interface and parses @@ -359,85 +362,182 @@ func (b *Board) UnmarshalBinary(data []byte) error { b.bbBlackBishop = bitboard(binary.BigEndian.Uint64(data[72:80])) b.bbBlackKnight = bitboard(binary.BigEndian.Uint64(data[80:88])) b.bbBlackPawn = bitboard(binary.BigEndian.Uint64(data[88:96])) - b.calcConvienceBBs(nil) + b.calcConvenienceBBs(nil) b.rebuildMailbox() return nil } -//nolint:mnd // magic number is used for bitboard size. -func (b *Board) update(m *Move) { - p1 := b.Piece(m.s1) +func (b *Board) update(m Move, eff moveEffect) { + if eff.moving == NoPiece { + return + } + p1 := eff.moving s1BB := bbForSquare(m.s1) s2BB := bbForSquare(m.s2) - // move s1 piece to s2 - for _, p := range allPieces { - bb := b.bbForPiece(p) - // remove what was at s2 - if err := b.setBBForPiece(p, bb & ^s2BB); err != nil { - panic(fmt.Sprintf("chess: invariant violation in board update: %v", err)) - } - // move what was at s1 to s2 - if bb.Occupied(m.s1) { - bb = b.bbForPiece(p) - if err := b.setBBForPiece(p, (bb & ^s1BB)|s2BB); err != nil { - panic(fmt.Sprintf("chess: invariant violation in board update: %v", err)) - } + whiteSqs := b.whiteSqs + blackSqs := b.blackSqs + + // Remove the captured piece from the occupancy aggregates before the + // moving piece's square changes. Doing the capture removal first means + // an unsafe move onto a friendly square (capPiece same color as the + // mover) clears capSqBB from the mover's aggregate and then re-adds s2BB + // below, so whiteSqs/blackSqs stay consistent with the piece bitboards + // and mailbox. Cap-effect semantics for legal captures are unchanged. + if eff.capPiece != NoPiece { + capSqBB := bbForSquare(eff.capSq) + b.setPieceBB(eff.capPiece, b.bbForPiece(eff.capPiece)&^capSqBB) + if eff.capPiece.Color() == White { + whiteSqs &^= capSqBB + } else { + blackSqs &^= capSqBB } + b.mailbox[eff.capSq] = NoPiece } - // check promotion - if m.promo != NoPieceType && p1 != NoPiece { - newPiece := NewPiece(m.promo, p1.Color()) - // remove pawn - bbPawn := b.bbForPiece(p1) - if err := b.setBBForPiece(p1, bbPawn & ^s1BB & ^s2BB); err != nil { - panic(fmt.Sprintf("chess: invariant violation in board update: %v", err)) - } - // add promo piece - bbPromo := b.bbForPiece(newPiece) - if err := b.setBBForPiece(newPiece, bbPromo|s2BB); err != nil { - panic(fmt.Sprintf("chess: invariant violation in board update: %v", err)) - } - b.mailbox[m.s1] = NoPiece - b.mailbox[m.s2] = newPiece + + // Move the moving piece between s1 and s2 on the color-occupancy bitboards. + if p1.Color() == White { + whiteSqs = (whiteSqs &^ s1BB) | s2BB } else { - b.mailbox[m.s1] = NoPiece - b.mailbox[m.s2] = p1 - } - // remove captured en passant piece - if m.HasTag(EnPassant) { - if p1.Color() == White { - b.bbBlackPawn = ^(bbForSquare(m.s2) << 8) & b.bbBlackPawn - b.mailbox[m.s2-8] = NoPiece + blackSqs = (blackSqs &^ s1BB) | s2BB + } + + b.setPieceBB(p1, b.bbForPiece(p1)&^s1BB) + + // Place the landing piece at s2 (a promotion piece when eff.landing != p1, + // the moving piece otherwise). For normal captures this overwrites the + // captured piece's mailbox entry left at m.s2 above. + if eff.landing != p1 { + b.setPieceBB(eff.landing, b.bbForPiece(eff.landing)|s2BB) + } else { + b.setPieceBB(p1, b.bbForPiece(p1)|s2BB) + } + b.mailbox[m.s1] = NoPiece + b.mailbox[m.s2] = eff.landing + + b.moveRookForCastle(eff, &whiteSqs, &blackSqs) + + b.whiteSqs = whiteSqs + b.blackSqs = blackSqs + b.emptySqs = ^(whiteSqs | blackSqs) + + switch { + case p1 == WhiteKing: + b.whiteKingSq = m.s2 + case p1 == BlackKing: + b.blackKingSq = m.s2 + case eff.capPiece == WhiteKing: + b.whiteKingSq = NoSquare + case eff.capPiece == BlackKing: + b.blackKingSq = NoSquare + } +} + +// unapply reverses update: it removes the landing piece from s2, restores the +// moving piece on s1, puts any captured piece back, and unmoves a castled +// rook. eff must be the same descriptor update was called with. Used by the +// MoveTree cursor's slim undo (cursorUndo); perft keeps the full-state copy. +func (b *Board) unapply(m Move, eff moveEffect) { + if eff.moving == NoPiece { + return + } + p1 := eff.moving + s1BB := bbForSquare(m.s1) + s2BB := bbForSquare(m.s2) + + whiteSqs := b.whiteSqs + blackSqs := b.blackSqs + + b.unmoveRookForCastle(eff, &whiteSqs, &blackSqs) + + // Remove the landing piece from s2 and put the moving piece back on s1. + // For a promotion (landing != moving) the promo piece leaves s2 and the + // original pawn returns to s1. + if eff.landing != p1 { + b.setPieceBB(eff.landing, b.bbForPiece(eff.landing)&^s2BB) + } else { + b.setPieceBB(p1, b.bbForPiece(p1)&^s2BB) + } + b.setPieceBB(p1, b.bbForPiece(p1)|s1BB) + if p1.Color() == White { + whiteSqs = (whiteSqs &^ s2BB) | s1BB + } else { + blackSqs = (blackSqs &^ s2BB) | s1BB + } + b.mailbox[m.s1] = p1 + b.mailbox[m.s2] = NoPiece + + // Restore the captured piece. For en passant capSq trails s2; for a + // capture promotion capSq == s2 and runs after the s2 mailbox clear above. + if eff.capPiece != NoPiece { + capSqBB := bbForSquare(eff.capSq) + b.setPieceBB(eff.capPiece, b.bbForPiece(eff.capPiece)|capSqBB) + if eff.capPiece.Color() == White { + whiteSqs |= capSqBB } else { - b.bbWhitePawn = ^(bbForSquare(m.s2) >> 8) & b.bbWhitePawn - b.mailbox[m.s2+8] = NoPiece + blackSqs |= capSqBB } + b.mailbox[eff.capSq] = eff.capPiece } - // move rook for castle + + b.whiteSqs = whiteSqs + b.blackSqs = blackSqs + b.emptySqs = ^(whiteSqs | blackSqs) + switch { - case p1.Color() == White && m.HasTag(KingSideCastle): - b.bbWhiteRook = b.bbWhiteRook & ^bbForSquare(H1) | bbForSquare(F1) - b.mailbox[H1] = NoPiece - b.mailbox[F1] = WhiteRook - case p1.Color() == White && m.HasTag(QueenSideCastle): - b.bbWhiteRook = (b.bbWhiteRook & ^bbForSquare(A1)) | bbForSquare(D1) - b.mailbox[A1] = NoPiece - b.mailbox[D1] = WhiteRook - case p1.Color() == Black && m.HasTag(KingSideCastle): - b.bbBlackRook = b.bbBlackRook & ^bbForSquare(H8) | bbForSquare(F8) - b.mailbox[H8] = NoPiece - b.mailbox[F8] = BlackRook - case p1.Color() == Black && m.HasTag(QueenSideCastle): - b.bbBlackRook = (b.bbBlackRook & ^bbForSquare(A8)) | bbForSquare(D8) - b.mailbox[A8] = NoPiece - b.mailbox[D8] = BlackRook - } - - b.calcConvienceBBs(m) -} - -func (b *Board) calcConvienceBBs(m *Move) { + case p1 == WhiteKing: + b.whiteKingSq = m.s1 + case p1 == BlackKing: + b.blackKingSq = m.s1 + case eff.capPiece == WhiteKing: + b.whiteKingSq = eff.capSq + case eff.capPiece == BlackKing: + b.blackKingSq = eff.capSq + } +} + +func (b *Board) unmoveRookForCastle(eff moveEffect, whiteSqs, blackSqs *bitboard) { + if eff.rookFrom == NoSquare { + return + } + rookPiece := NewPiece(Rook, eff.moving.Color()) + fromBB := bbForSquare(eff.rookFrom) + toBB := bbForSquare(eff.rookTo) + b.setPieceBB(rookPiece, b.bbForPiece(rookPiece)&^toBB|fromBB) + b.mailbox[eff.rookFrom] = rookPiece + b.mailbox[eff.rookTo] = NoPiece + if eff.moving.Color() == White { + *whiteSqs = (*whiteSqs &^ toBB) | fromBB + } else { + *blackSqs = (*blackSqs &^ toBB) | fromBB + } +} + +func (b *Board) setPieceBB(p Piece, bb bitboard) { + if err := b.setBBForPiece(p, bb); err != nil { + panic(fmt.Sprintf("chess: invariant violation in board update: %v", err)) + } +} + +//nolint:mnd // magic number is used for bitboard shifts. +func (b *Board) moveRookForCastle(eff moveEffect, whiteSqs, blackSqs *bitboard) { + if eff.rookFrom == NoSquare { + return + } + rookPiece := NewPiece(Rook, eff.moving.Color()) + fromBB := bbForSquare(eff.rookFrom) + toBB := bbForSquare(eff.rookTo) + b.setPieceBB(rookPiece, b.bbForPiece(rookPiece)&^fromBB|toBB) + b.mailbox[eff.rookFrom] = NoPiece + b.mailbox[eff.rookTo] = rookPiece + if eff.moving.Color() == White { + *whiteSqs = (*whiteSqs &^ fromBB) | toBB + } else { + *blackSqs = (*blackSqs &^ fromBB) | toBB + } +} + +func (b *Board) calcConvenienceBBs(m *Move) { whiteSqs := b.bbWhiteKing | b.bbWhiteQueen | b.bbWhiteRook | b.bbWhiteBishop | b.bbWhiteKnight | b.bbWhitePawn blackSqs := b.bbBlackKing | b.bbBlackQueen | b.bbBlackRook | b.bbBlackBishop | b.bbBlackKnight | b.bbBlackPawn emptySqs := ^(whiteSqs | blackSqs) @@ -508,6 +608,64 @@ func (b *Board) isOccupied(sq Square) bool { return !b.emptySqs.Occupied(sq) } +// HasInsufficientMaterial reports whether color c cannot force checkmate +// against any opposing material. It returns true for a lone king, king plus +// a single minor piece, or king plus bishops that are all confined to one +// square color. It returns false when c has a queen, rook, pawn, knight, or +// bishops on both square colors. +func (b *Board) HasInsufficientMaterial(c Color) bool { + var qrb, bishops, knights bitboard + switch c { + case White: + qrb = b.bbWhiteQueen | b.bbWhiteRook | b.bbWhitePawn + bishops = b.bbWhiteBishop + knights = b.bbWhiteKnight + case Black: + qrb = b.bbBlackQueen | b.bbBlackRook | b.bbBlackPawn + bishops = b.bbBlackBishop + knights = b.bbBlackKnight + default: + return true + } + + // Queen, rook, or pawn can all deliver mate. + if qrb != 0 { + return false + } + + // Only a king. + if bishops == 0 && knights == 0 { + return true + } + + // King plus a single minor piece cannot force mate. + if bits.OnesCount64(uint64(bishops|knights)) == 1 { + return true + } + + // Multiple minor pieces: insufficient if they are all bishops on the same + // square color. Any knight makes the configuration potentially mating. + if knights != 0 { + return false + } + + var whiteSqBishops, blackSqBishops int + for bb := bishops; bb != 0; bb &= bb - 1 { + sq := squareFromBit(bb & -bb) + if sq.color() == White { + whiteSqBishops++ + } else { + blackSqBishops++ + } + } + return whiteSqBishops == 0 || blackSqBishops == 0 +} + +// hasSufficientMaterial reports whether the position has enough material to +// continue. It is the whole-position auto-draw predicate used by the game +// outcome classifier and intentionally differs from a simple AND of the +// per-color query: K+B vs K+B with bishops on opposite colors is not an +// automatic draw under FIDE rules. func (b *Board) hasSufficientMaterial() bool { // queen, rook, or pawn exist if (b.bbWhiteQueen | b.bbWhiteRook | b.bbWhitePawn | @@ -518,12 +676,25 @@ func (b *Board) hasSufficientMaterial() bool { if b.bbWhiteKing == 0 || b.bbBlackKing == 0 { return true } - count := map[PieceType]int{} - pieceMap := b.SquareMap() - for _, p := range pieceMap { - count[p.Type()]++ + var count [7]int + whiteCount := 0 + blackCount := 0 + for sq, p := range b.mailbox { + pieceType := p.Type() + if pieceType == NoPieceType { + continue + } + count[pieceType]++ + if pieceType == Bishop { + switch Square(sq).color() { + case White: + whiteCount++ + case Black: + blackCount++ + } + } } - // king versus king + // king versus king if count[Bishop] == 0 && count[Knight] == 0 { return false } @@ -537,18 +708,6 @@ func (b *Board) hasSufficientMaterial() bool { } // king and bishop(s) versus king and bishop(s) with the bishops on the same colour. if count[Knight] == 0 { - whiteCount := 0 - blackCount := 0 - for sq, p := range pieceMap { - if p.Type() == Bishop { - switch sq.color() { - case White: - whiteCount++ - case Black: - blackCount++ - } - } - } if whiteCount == 0 || blackCount == 0 { return false } @@ -613,7 +772,7 @@ func (b *Board) setBBForPiece(p Piece, bb bitboard) error { case BlackPawn: b.bbBlackPawn = bb default: - return fmt.Errorf("invalid piece %s", p) + return fmt.Errorf("chess: invalid piece %s", p) } return nil } diff --git a/board_invariants_test.go b/board_invariants_test.go new file mode 100644 index 00000000..3dee0efc --- /dev/null +++ b/board_invariants_test.go @@ -0,0 +1,180 @@ +package chess + +import ( + "fmt" + "testing" +) + +func TestMailboxConsistency(t *testing.T) { + t.Parallel() + + playAndVerify := func(t *testing.T, g *Game, moves []string) { + t.Helper() + for _, moveStr := range moves { + move, err := uciNotation{}.Decode(g.Position(), moveStr) + if err != nil { + t.Fatalf("failed to parse move %s: %v", moveStr, err) + } + if _, err := g.Move(move, nil); err != nil { + t.Fatalf("failed to play move %s: %v", moveStr, err) + } + if err := verifyMailboxConsistency(g.Position().Board()); err != nil { + t.Fatalf("mailbox inconsistent after %s: %v", moveStr, err) + } + } + } + + t.Run("starting_position", func(t *testing.T) { + t.Parallel() + g := NewGame() + if err := verifyMailboxConsistency(g.Position().Board()); err != nil { + t.Fatal(err) + } + }) + + t.Run("after_quiet_moves", func(t *testing.T) { + t.Parallel() + playAndVerify(t, NewGame(), []string{"e2e4", "e7e5", "g1f3", "b8c6", "f1c4", "g8f6", "d2d3", "d7d5"}) + }) + + t.Run("castling", func(t *testing.T) { + t.Parallel() + playAndVerify(t, NewGame(), []string{"e2e4", "e7e5", "g1f3", "b8c6", "f1c4", "g8f6", "e1g1", "f8c5", "d2d3", "e8g8"}) + }) + + t.Run("en_passant", func(t *testing.T) { + t.Parallel() + playAndVerify(t, NewGame(), []string{"e2e4", "a7a6", "e4e5", "d7d5", "e5d6"}) + }) + + t.Run("promotion", func(t *testing.T) { + t.Parallel() + opt, err := FEN("4k3/P7/8/8/8/8/8/4K3 w - - 0 1") + if err != nil { + t.Fatal(err) + } + playAndVerify(t, NewGame(opt), []string{"a7a8q"}) + }) + + t.Run("perft_positions", func(t *testing.T) { + fens := []string{ + "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1", + "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1", + "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1", + "rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8", + "r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - - 0 10", + } + for _, fen := range fens { + t.Run(fen, func(t *testing.T) { + opt, err := FEN(fen) + if err != nil { + t.Fatal(err) + } + g := NewGame(opt) + if err := verifyMailboxConsistency(g.Position().Board()); err != nil { + t.Fatal(err) + } + }) + } + }) + + t.Run("empty_board", func(t *testing.T) { + b, err := NewBoard(map[Square]Piece{}) + if err != nil { + t.Fatal(err) + } + if err := verifyMailboxConsistency(b); err != nil { + t.Fatal(err) + } + }) + + t.Run("binary_round_trip", func(t *testing.T) { + g := NewGame() + board := g.Position().Board() + data, err := board.MarshalBinary() + if err != nil { + t.Fatal(err) + } + cp := &Board{} + if err := cp.UnmarshalBinary(data); err != nil { + t.Fatal(err) + } + if err := verifyMailboxConsistency(cp); err != nil { + t.Fatalf("unmarshaled board mailbox inconsistent: %v", err) + } + if cp.String() != board.String() { + t.Errorf("binary round-trip changed board: got %q, want %q", cp.String(), board.String()) + } + }) + + t.Run("transformations", func(t *testing.T) { + board := NewGame().Position().Board() + + flipped, err := board.Flip(UpDown) + if err != nil { + t.Fatal(err) + } + if err := verifyMailboxConsistency(flipped); err != nil { + t.Fatalf("flipped board mailbox inconsistent: %v", err) + } + + transposed, err := board.Transpose() + if err != nil { + t.Fatal(err) + } + if err := verifyMailboxConsistency(transposed); err != nil { + t.Fatalf("transposed board mailbox inconsistent: %v", err) + } + + rotated, err := board.Rotate() + if err != nil { + t.Fatal(err) + } + if err := verifyMailboxConsistency(rotated); err != nil { + t.Fatalf("rotated board mailbox inconsistent: %v", err) + } + }) +} + +func verifyMailboxConsistency(b *Board) error { + var whiteSqs bitboard + var blackSqs bitboard + var occupied bitboard + for sq := range numOfSquaresInBoard { + square := Square(sq) + mailboxPiece := b.Piece(square) + bitboardPiece := NoPiece + + for _, p := range allPieces { + if b.bbForPiece(p).Occupied(square) { + bitboardPiece = p + break + } + } + + if mailboxPiece != bitboardPiece { + return fmt.Errorf("mailbox/bitboard mismatch at %s: mailbox=%s, bitboard=%s", + square.String(), mailboxPiece.String(), bitboardPiece.String()) + } + if bitboardPiece == NoPiece { + continue + } + sqBB := bbForSquare(square) + occupied |= sqBB + if bitboardPiece.Color() == White { + whiteSqs |= sqBB + } else { + blackSqs |= sqBB + } + } + if b.whiteSqs != whiteSqs { + return fmt.Errorf("white aggregate occupancy mismatch: got %s, want %s", b.whiteSqs, whiteSqs) + } + if b.blackSqs != blackSqs { + return fmt.Errorf("black aggregate occupancy mismatch: got %s, want %s", b.blackSqs, blackSqs) + } + if b.emptySqs != ^occupied { + return fmt.Errorf("empty aggregate occupancy mismatch: got %s, want %s", b.emptySqs, ^occupied) + } + return nil +} diff --git a/board_set_queries_test.go b/board_set_queries_test.go new file mode 100644 index 00000000..6192739e --- /dev/null +++ b/board_set_queries_test.go @@ -0,0 +1,26 @@ +package chess + +import "testing" + +func TestBoardBitboardQueries(t *testing.T) { + b := StartingPosition().Board() + + if b.White().Popcount() != 16 { + t.Fatalf("expected 16 white pieces, got %d", b.White().Popcount()) + } + if b.Black().Popcount() != 16 { + t.Fatalf("expected 16 black pieces, got %d", b.Black().Popcount()) + } + if b.Occupied().Popcount() != 32 { + t.Fatalf("expected 32 occupied squares, got %d", b.Occupied().Popcount()) + } + if b.Empty().Popcount() != 32 { + t.Fatalf("expected 32 empty squares, got %d", b.Empty().Popcount()) + } + if b.Pieces(Pawn, White).Popcount() != 8 { + t.Fatalf("expected 8 white pawns, got %d", b.Pieces(Pawn, White).Popcount()) + } + if b.Color(Black).Popcount() != 16 { + t.Fatalf("expected 16 black pieces via Color, got %d", b.Color(Black).Popcount()) + } +} diff --git a/board_test.go b/board_test.go index 410c2819..21d31795 100644 --- a/board_test.go +++ b/board_test.go @@ -1,203 +1,311 @@ -package chess +package chess_test import ( + "bytes" "fmt" + "strings" "testing" + + "github.com/corentings/chess/v3" ) -func TestBoardTextSerialization(t *testing.T) { - fen := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR" - b := &Board{} +func boardFromFEN(t *testing.T, fen string) *chess.Board { + t.Helper() + b := &chess.Board{} if err := b.UnmarshalText([]byte(fen)); err != nil { - t.Fatal("recieved unexpected error", err) + t.Fatal(err) } - txt, err := b.MarshalText() - if err != nil { - t.Fatal("recieved unexpected error", err) + return b +} + +var boardFENs = []struct { + name string + fen string +}{ + {"startpos", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR"}, + {"empty", "8/8/8/8/8/8/8/8"}, + {"mid", "r1bqkbnr/pppp1ppp/2n5/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R"}, + {"kiwipete", "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R"}, +} + +func TestBoard_TextRoundTrip(t *testing.T) { + for _, tt := range boardFENs { + t.Run(tt.name, func(t *testing.T) { + b := boardFromFEN(t, tt.fen) + txt, err := b.MarshalText() + if err != nil { + t.Fatal(err) + } + if string(txt) != tt.fen { + t.Errorf("MarshalText = %q, want %q", string(txt), tt.fen) + } + }) } - if fen != string(txt) { - t.Fatalf("fen expected board string %s but got %s", fen, string(txt)) +} + +func TestBoard_BinaryRoundTrip(t *testing.T) { + for _, tt := range boardFENs { + t.Run(tt.name, func(t *testing.T) { + b := boardFromFEN(t, tt.fen) + data, err := b.MarshalBinary() + if err != nil { + t.Fatal(err) + } + if len(data) != 96 { + t.Fatalf("MarshalBinary len = %d, want 96 (12 bitboards * 8 bytes)", len(data)) + } + cp := &chess.Board{} + if err := cp.UnmarshalBinary(data); err != nil { + t.Fatal(err) + } + if cp.String() != tt.fen { + t.Errorf("binary round-trip = %q, want %q", cp.String(), tt.fen) + } + redata, err := cp.MarshalBinary() + if err != nil { + t.Fatal(err) + } + if !bytes.Equal(data, redata) { + t.Errorf("MarshalBinary not byte-order stable: %v != %v", data, redata) + } + }) } } -func TestBoardBinarySerialization(t *testing.T) { - g := NewGame() - board := g.Position().Board() - b, err := board.MarshalBinary() - if err != nil { - t.Fatal("recieved unexpected error", err) +func TestBoard_SquareMapRoundTrip(t *testing.T) { + for _, tt := range boardFENs { + t.Run(tt.name, func(t *testing.T) { + b := boardFromFEN(t, tt.fen) + rebuilt, err := chess.NewBoard(b.SquareMap()) + if err != nil { + t.Fatal(err) + } + if rebuilt.String() != b.String() { + t.Errorf("NewBoard(SquareMap()) = %q, want %q", rebuilt.String(), b.String()) + } + }) } - cpBoard := &Board{} - err = cpBoard.UnmarshalBinary(b) - if err != nil { - t.Fatal("recieved unexpected error", err) +} + +func TestBoard_PieceAtKnownSquares(t *testing.T) { + b := boardFromFEN(t, "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR") + tests := []struct { + sq chess.Square + want chess.Piece + }{ + {chess.A1, chess.WhiteRook}, + {chess.E1, chess.WhiteKing}, + {chess.D1, chess.WhiteQueen}, + {chess.A2, chess.WhitePawn}, + {chess.E8, chess.BlackKing}, + {chess.D8, chess.BlackQueen}, + {chess.H8, chess.BlackRook}, + {chess.A7, chess.BlackPawn}, + {chess.E4, chess.NoPiece}, + {chess.D5, chess.NoPiece}, } - s := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR" - if s != cpBoard.String() { - t.Fatalf("expected board string %s but got %s", s, cpBoard.String()) + for _, tt := range tests { + t.Run(tt.sq.String(), func(t *testing.T) { + if got := b.Piece(tt.sq); got != tt.want { + t.Errorf("Piece(%s) = %v, want %v", tt.sq, got, tt.want) + } + }) } } -func TestBoardRotation(t *testing.T) { - fens := []string{ +func TestBoard_RotateNinetyDegreesClockwise(t *testing.T) { + want := []string{ "RP4pr/NP4pn/BP4pb/QP4pq/KP4pk/BP4pb/NP4pn/RP4pr", "RNBKQBNR/PPPPPPPP/8/8/8/8/pppppppp/rnbkqbnr", "rp4PR/np4PN/bp4PB/kp4PK/qp4PQ/bp4PB/np4PN/rp4PR", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR", } - g := NewGame() - board := g.Position().Board() - for i := range fens { - var err error - board, err = board.Rotate() - if err != nil { - t.Fatalf("Rotate() error = %v", err) - } - if fens[i] != board.String() { - t.Fatalf("expected board string %s but got %s", fens[i], board.String()) - } - } -} - -func TestBoardFlip(t *testing.T) { - g := NewGame() - board := g.Position().Board() - var err error - board, err = board.Flip(UpDown) - if err != nil { - t.Fatalf("Flip(UpDown) error = %v", err) - } - b := "RNBQKBNR/PPPPPPPP/8/8/8/8/pppppppp/rnbqkbnr" - if b != board.String() { - t.Fatalf("expected board string %s but got %s", b, board.String()) + start := boardFromFEN(t, "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR") + board := start + for i, w := range want { + t.Run(rotatedLabel(i+1), func(t *testing.T) { + var err error + board, err = board.Rotate() + if err != nil { + t.Fatalf("Rotate() error = %v", err) + } + if board.String() != w { + t.Errorf("Rotate() = %q, want %q", board.String(), w) + } + }) } - board, err = board.Flip(UpDown) + rotated, err := start.Rotate() if err != nil { - t.Fatalf("Flip(UpDown) error = %v", err) + t.Fatal(err) } - b = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR" - if b != board.String() { - t.Fatalf("expected board string %s but got %s", b, board.String()) - } - board, err = board.Flip(LeftRight) + flipped, err := start.Flip(chess.UpDown) if err != nil { - t.Fatalf("Flip(LeftRight) error = %v", err) - } - b = "rnbkqbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBKQBNR" - if b != board.String() { - t.Fatalf("expected board string %s but got %s", b, board.String()) + t.Fatal(err) } - board, err = board.Flip(LeftRight) + transposed, err := flipped.Transpose() if err != nil { - t.Fatalf("Flip(LeftRight) error = %v", err) + t.Fatal(err) } - b = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR" - if b != board.String() { - t.Fatalf("expected board string %s but got %s", b, board.String()) + if rotated.String() != transposed.String() { + t.Errorf("Rotate() = %q, want Flip(UpDown).Transpose() = %q", rotated.String(), transposed.String()) } } -func TestBoardTranspose(t *testing.T) { - g := NewGame() - board := g.Position().Board() - var err error - board, err = board.Transpose() - if err != nil { - t.Fatalf("Transpose() error = %v", err) - } - b := "rp4PR/np4PN/bp4PB/qp4PQ/kp4PK/bp4PB/np4PN/rp4PR" - if b != board.String() { - t.Fatalf("expected board string %s but got %s", b, board.String()) +func rotatedLabel(n int) string { + switch n { + case 1: + return "rotated_90cw" + case 2: + return "rotated_180" + case 3: + return "rotated_270cw" + default: + return "rotated_360_identity" } } -// TestMailboxConsistency verifies that the mailbox array stays in sync with bitboards -// across various board operations including moves, flips, transposes, and rotations. -func TestMailboxConsistency(t *testing.T) { - g := NewGame() - pos := g.Position() - - // Test 1: Starting position - if err := verifyMailboxConsistency(pos.Board()); err != nil { - t.Fatalf("starting position mailbox inconsistent: %v", err) - } - - // Test 2: After several moves - moves := []string{"e2e4", "e7e5", "g1f3", "b8c6", "f1c4", "g8f6", "d2d3", "d7d5"} - for _, moveStr := range moves { - move, err := UCINotation{}.Decode(g.Position(), moveStr) +func TestBoard_FlipIsInvolution(t *testing.T) { + t.Run("UpDown_is_involution", func(t *testing.T) { + start := boardFromFEN(t, "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR") + once, err := start.Flip(chess.UpDown) if err != nil { - t.Fatalf("failed to parse move %s: %v", moveStr, err) + t.Fatal(err) } - if err := g.Move(move, nil); err != nil { - t.Fatalf("failed to play move %s: %v", moveStr, err) + if want := "RNBQKBNR/PPPPPPPP/8/8/8/8/pppppppp/rnbqkbnr"; once.String() != want { + t.Errorf("Flip(UpDown) = %q, want %q", once.String(), want) } - } - if err := verifyMailboxConsistency(g.Position().Board()); err != nil { - t.Fatalf("after moves mailbox inconsistent: %v", err) - } - - // Test 3: Board transformations - board := g.Position().Board() + twice, err := once.Flip(chess.UpDown) + if err != nil { + t.Fatal(err) + } + if twice.String() != start.String() { + t.Errorf("Flip(UpDown).Flip(UpDown) = %q, want identity %q", twice.String(), start.String()) + } + }) + t.Run("LeftRight_is_involution", func(t *testing.T) { + start := boardFromFEN(t, "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR") + once, err := start.Flip(chess.LeftRight) + if err != nil { + t.Fatal(err) + } + if want := "rnbkqbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBKQBNR"; once.String() != want { + t.Errorf("Flip(LeftRight) = %q, want %q", once.String(), want) + } + twice, err := once.Flip(chess.LeftRight) + if err != nil { + t.Fatal(err) + } + if twice.String() != start.String() { + t.Errorf("Flip(LeftRight).Flip(LeftRight) = %q, want identity %q", twice.String(), start.String()) + } + }) +} - flipped, err := board.Flip(UpDown) +func TestBoard_TransposeIsInvolution(t *testing.T) { + start := boardFromFEN(t, "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR") + once, err := start.Transpose() if err != nil { - t.Fatalf("Flip error: %v", err) + t.Fatal(err) } - if err := verifyMailboxConsistency(flipped); err != nil { - t.Fatalf("flipped board mailbox inconsistent: %v", err) + if want := "rp4PR/np4PN/bp4PB/qp4PQ/kp4PK/bp4PB/np4PN/rp4PR"; once.String() != want { + t.Errorf("Transpose() = %q, want %q", once.String(), want) } - - transposed, err := board.Transpose() + twice, err := once.Transpose() if err != nil { - t.Fatalf("Transpose error: %v", err) + t.Fatal(err) } - if err := verifyMailboxConsistency(transposed); err != nil { - t.Fatalf("transposed board mailbox inconsistent: %v", err) + if twice.String() != start.String() { + t.Errorf("Transpose().Transpose() = %q, want identity %q", twice.String(), start.String()) } +} - rotated, err := board.Rotate() - if err != nil { - t.Fatalf("Rotate error: %v", err) +func TestBoard_DrawReturnsASCIIArt(t *testing.T) { + b := boardFromFEN(t, "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR") + s := b.Draw() + if !strings.Contains(s, " A B C D E F G H") { + t.Errorf("Draw() missing file header, got:\n%s", s) + } + if !strings.Contains(s, "8") || !strings.Contains(s, "1") { + t.Errorf("Draw() missing rank markers, got:\n%s", s) } - if err := verifyMailboxConsistency(rotated); err != nil { - t.Fatalf("rotated board mailbox inconsistent: %v", err) + if !strings.Contains(s, "♚") { + t.Errorf("Draw() missing black king glyph, got:\n%s", s) + } + if !strings.Contains(s, "-") { + t.Errorf("Draw() missing empty-square marker, got:\n%s", s) } } -// verifyMailboxConsistency checks that every square in the mailbox matches the -// piece found by scanning bitboards. -func verifyMailboxConsistency(b *Board) error { - for sq := range numOfSquaresInBoard { - square := Square(sq) - mailboxPiece := b.Piece(square) - bitboardPiece := NoPiece +func TestBoard_Draw2AllPerspectives(t *testing.T) { + b := boardFromFEN(t, "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR") + for _, tc := range []struct { + name string + persp chess.Color + darkMode bool + }{ + {"white_light", chess.White, false}, + {"white_dark", chess.White, true}, + {"black_light", chess.Black, false}, + {"black_dark", chess.Black, true}, + } { + t.Run(tc.name, func(t *testing.T) { + s := b.Draw2(tc.persp, tc.darkMode) + if !strings.Contains(s, "♔") { + t.Errorf("Draw2(%v,%v) missing white king glyph, got:\n%s", tc.persp, tc.darkMode, s) + } + if !strings.Contains(s, "-") { + t.Errorf("Draw2(%v,%v) missing empty-square marker, got:\n%s", tc.persp, tc.darkMode, s) + } + }) + } +} - // Find which piece (if any) occupies this square in bitboards - for _, p := range allPieces { - if b.bbForPiece(p).Occupied(square) { - bitboardPiece = p - break +func TestBoard_UnmarshalTextErrors(t *testing.T) { + tests := []struct { + name string + fen string + }{ + {"missing_rank", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP"}, + {"bad_char", "rnbqkbnZ/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR"}, + {"empty", ""}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + b := &chess.Board{} + if err := b.UnmarshalText([]byte(tt.fen)); err == nil { + t.Errorf("UnmarshalText(%q) = nil, want error", tt.fen) } - } + }) + } +} - if mailboxPiece != bitboardPiece { - return fmt.Errorf("mailbox/bitboard mismatch at %s: mailbox=%s, bitboard=%s", - square.String(), mailboxPiece.String(), bitboardPiece.String()) - } +func TestBoard_UnmarshalBinaryErrors(t *testing.T) { + for _, n := range []int{0, 95, 97} { + t.Run(fmt.Sprintf("len_%d", n), func(t *testing.T) { + b := &chess.Board{} + if err := b.UnmarshalBinary(make([]byte, n)); err == nil { + t.Errorf("UnmarshalBinary(len=%d) = nil, want error", n) + } + }) } - return nil } func BenchmarkPieceMailbox(b *testing.B) { - g := NewGame() + g := chess.NewGame() board := g.Position().Board() b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { - _ = board.Piece(A1) - _ = board.Piece(E4) - _ = board.Piece(H8) + for range b.N { + _ = board.Piece(chess.A1) + _ = board.Piece(chess.E4) + _ = board.Piece(chess.H8) + } +} + +func BenchmarkBoardString(b *testing.B) { + board := chess.StartingPosition().Board() + for b.Loop() { + _ = board.String() } } diff --git a/canonical_move_seam_test.go b/canonical_move_seam_test.go new file mode 100644 index 00000000..f244fc0a --- /dev/null +++ b/canonical_move_seam_test.go @@ -0,0 +1,130 @@ +package chess + +import ( + "testing" +) + +// TestMoveCanonicalizesStalenessForSpecialMove guards the original report +// friction: a legal Move with missing or false derived tags must surface as +// the canonical generated Move through the safe seam (resolveCanonicalMove), +// not as the caller-supplied value. Without this guard, a legal e1g1 without +// its KingSideCastle tag would advance the cursor while leaving the rook +// unmoved. +func TestMoveCanonicalizesStalenessForSpecialMove(t *testing.T) { + g := NewGame() + if _, err := g.MoveText("e4", SAN(), nil); err != nil { + t.Fatalf("setup e4: %v", err) + } + if _, err := g.MoveText("e5", SAN(), nil); err != nil { + t.Fatalf("setup e5: %v", err) + } + if _, err := g.MoveText("Nf3", SAN(), nil); err != nil { + t.Fatalf("setup Nf3: %v", err) + } + if _, err := g.MoveText("Nc6", SAN(), nil); err != nil { + t.Fatalf("setup Nc6: %v", err) + } + if _, err := g.MoveText("Bc4", SAN(), nil); err != nil { + t.Fatalf("setup Bc4: %v", err) + } + if _, err := g.MoveText("Bc5", SAN(), nil); err != nil { + t.Fatalf("setup Bc5: %v", err) + } + + goodCastle := Move{s1: E1, s2: G1, tags: 0} + if _, err := g.Move(goodCastle, nil); err != nil { + t.Fatalf("safe castle without KingSideCastle tag should be canonicalised: %v", err) + } + if !g.MoveTree().Current().Move().HasTag(KingSideCastle) { + t.Fatalf("stored Move must carry the KingSideCastle tag after canonicalisation; got %v", + g.MoveTree().Current().Move()) + } + pos := g.Position() + if pos.Board().Piece(F1) != WhiteRook || pos.Board().Piece(H1) != NoPiece { + t.Fatalf("rook must have moved h1→f1 after canonicalised castle, got F1=%v H1=%v", + pos.Board().Piece(F1), pos.Board().Piece(H1)) + } +} + +// TestMoveRejectsNullPinnedByUnsafeContract preserves the existing user-visible +// contract: Game.Move rejects Null-tagged values. AddVariation normalises them +// instead — see TestAddVariationNormalisesNull. +func TestMoveRejectsNullPinnedByUnsafeContract(t *testing.T) { + g := NewGame() + if _, err := g.Move(NewNullMove(), nil); err == nil { + t.Fatal("Game.Move must reject Null-tagged Move") + } +} + +// TestAddVariationNormalisesNull exercises the chosen policy: a Null-tagged +// Move passed to AddVariation is stored as the canonical Null representation +// regardless of stray origin, destination, or promotion. +func TestAddVariationNormalisesNull(t *testing.T) { + g := NewGame() + root := g.MoveTree().Root() + spurious := Move{s1: E2, s2: E4, promo: Queen, tags: Null} + node, err := g.MoveTree().AddVariation(root, spurious) + if err != nil { + t.Fatalf("AddVariation(NewNullMove form) error: %v", err) + } + stored := node.Move() + if !stored.HasTag(Null) { + t.Fatalf("stored Move must carry Null tag; got %v", stored) + } +} + +// TestSafeMoveRejectsRepairOnExistingSubtree pins the no-mutation contract: +// when an existing Move occurrence has continuations and stale tags, safe +// insertion refuses rather than risking an inconsistent subtree. The setup +// injects a stale-tagged MoveNode (alongside a child) directly into the +// MoveTree to demonstrate the guard; without the repair-or-reject check +// the safe path would either silently overwrite the stored Move (corrupting +// the subtree) or leave stale tags in place. +func TestSafeMoveRejectsRepairOnExistingSubtree(t *testing.T) { + g := NewGame() + tree := g.MoveTree() + root := tree.Root() + + staleMove := Move{s1: E2, s2: E4, tags: Capture} + continuation := Move{s1: E7, s2: E5, tags: Capture} + staleNode := &MoveNode{move: staleMove, parent: root, tree: tree} + childNode := &MoveNode{move: continuation, parent: staleNode, tree: tree} + staleNode.children = append(staleNode.children, childNode) + root.children = append(root.children, staleNode) + + beforeRootLen := len(root.children) + beforeStaleChildren := len(staleNode.children) + beforeStaleMove := staleNode.move + beforeChildMove := childNode.move + beforeUndoLen := len(tree.undos) + beforeCurrent := tree.Current() + + _, err := g.Move(Move{s1: E2, s2: E4}, nil) + if err == nil { + t.Fatal("safe Move on a stale Move with continuations must be refused") + } + if err.Error() != "chess: cannot canonicalise existing Move occurrence with continuations" { + t.Fatalf("unexpected rejection error: %v", err) + } + + if len(root.children) != beforeRootLen { + t.Fatalf("topology mutated on reject: root.children %d → %d", + beforeRootLen, len(root.children)) + } + if len(staleNode.children) != beforeStaleChildren { + t.Fatalf("subtree mutated on reject: staleNode.children %d → %d", + beforeStaleChildren, len(staleNode.children)) + } + if staleNode.move != beforeStaleMove { + t.Fatalf("stale Move mutated on reject: %v → %v", beforeStaleMove, staleNode.move) + } + if childNode.move != beforeChildMove { + t.Fatalf("continuation mutated on reject: %v → %v", beforeChildMove, childNode.move) + } + if len(tree.undos) != beforeUndoLen { + t.Fatalf("undo stack mutated on reject: %d → %d", beforeUndoLen, len(tree.undos)) + } + if tree.Current() != beforeCurrent { + t.Fatal("active cursor mutated on reject") + } +} diff --git a/castling.go b/castling.go new file mode 100644 index 00000000..338cfdd8 --- /dev/null +++ b/castling.go @@ -0,0 +1,182 @@ +package chess + +// castleMoves returns all legal castling moves for the current position. +// +// A castling move is legal if: +// - The king has castling rights in that direction +// - The squares between king and rook are empty +// - The king is not in check +// - The king does not pass through check +func hasCastleMove(pos *Position) bool { + var castles [2]Move + return castleMovesInto(pos, &castles, generateLegalOnly) > 0 +} + +func castleMovesInto(pos *Position, moves *[2]Move, mode moveGenerationMode) int { + if pos.variant == Chess960 { + return chess960CastleMovesInto(pos, moves, mode) + } + return standardCastleMovesInto(pos, moves, mode) +} + +// standardCastleMovesInto generates castling moves for the standard variant, +// where the king starts on e1/e8 and the rooks on a1/h1/a8/h8. +func standardCastleMovesInto(pos *Position, moves *[2]Move, mode moveGenerationMode) int { + count := 0 + + kingSide := pos.castleRights.CanCastle(pos.Turn(), KingSide) + queenSide := pos.castleRights.CanCastle(pos.Turn(), QueenSide) + + // white king side + if pos.turn == White && kingSide && + (^pos.board.emptySqs&(bbForSquare(F1)|bbForSquare(G1))) == 0 && + !squaresAreAttacked(pos, F1, G1) && + !pos.inCheck { + m := Move{s1: E1, s2: G1} + tag, _ := newLegality(pos, mode).legal(m) + m.tags = tag + moves[count] = m + count++ + } + + // white queen side + if pos.turn == White && queenSide && + (^pos.board.emptySqs&(bbForSquare(B1)|bbForSquare(C1)|bbForSquare(D1))) == 0 && + !squaresAreAttacked(pos, C1, D1) && + !pos.inCheck { + m := Move{s1: E1, s2: C1} + tag, _ := newLegality(pos, mode).legal(m) + m.tags = tag + moves[count] = m + count++ + } + + // black king side + if pos.turn == Black && kingSide && + (^pos.board.emptySqs&(bbForSquare(F8)|bbForSquare(G8))) == 0 && + !squaresAreAttacked(pos, F8, G8) && + !pos.inCheck { + m := Move{s1: E8, s2: G8} + tag, _ := newLegality(pos, mode).legal(m) + m.tags = tag + moves[count] = m + count++ + } + + // black queen side + if pos.turn == Black && queenSide && + (^pos.board.emptySqs&(bbForSquare(B8)|bbForSquare(C8)|bbForSquare(D8))) == 0 && + !squaresAreAttacked(pos, C8, D8) && + !pos.inCheck { + m := Move{s1: E8, s2: C8} + tag, _ := newLegality(pos, mode).legal(m) + m.tags = tag + moves[count] = m + count++ + } + + return count +} + +// chess960CastleMovesInto generates castling moves for the Chess960 variant. +// Castling destinations are the standard squares (king to g/c, rook to f/d), +// but the king and rook origins are derived from the board: the king is on its +// back rank, and the castling rook is the nearest friendly rook to the king's +// right (king side) or left (queen side). The king and rook paths must be clear +// (each allowed to stand in the other's way), and the king must not be in check +// or pass through or land on an attacked square. +func chess960CastleMovesInto(pos *Position, moves *[2]Move, mode moveGenerationMode) int { + count := 0 + c := pos.turn + var rank Rank + var kSideKingTo, qSideKingTo, kSideRookTo, qSideRookTo Square + if c == White { + rank = Rank1 + kSideKingTo, qSideKingTo, kSideRookTo, qSideRookTo = G1, C1, F1, D1 + } else { + rank = Rank8 + kSideKingTo, qSideKingTo, kSideRookTo, qSideRookTo = G8, C8, F8, D8 + } + kingFile := backRankKingFile(&pos.board, c) + if kingFile < 0 { + return 0 + } + kingFrom := NewSquare(File(kingFile), rank) + + tryCastle := func(side Side, kingTo, rookTo Square) { + rookFile := rookFileForSide(&pos.board, c, kingFile, side) + if rookFile < 0 { + return + } + rookFrom := NewSquare(File(rookFile), rank) + if !chess960CastlePathClear(&pos.board, kingFrom, kingTo, rookFrom, rookTo) { + return + } + if !chess960KingTransitSafe(pos, kingFrom, kingTo) { + return + } + m := Move{s1: kingFrom, s2: kingTo} + tag, _ := newLegality(pos, mode).legal(m) + m.tags = tag + moves[count] = m + count++ + } + if pos.castleRights.CanCastle(c, KingSide) { + tryCastle(KingSide, kSideKingTo, kSideRookTo) + } + if pos.castleRights.CanCastle(c, QueenSide) { + tryCastle(QueenSide, qSideKingTo, qSideRookTo) + } + return count +} + +// chess960CastlePathClear reports whether all squares the king and rook traverse +// during a Chess960 castle are clear of pieces other than the castling king and +// rook themselves. The squares strictly between each piece's start and end must +// be empty, except that the rook may stand in the king's path and the king may +// stand in the rook's path (each moves out of the other's way). This covers the +// stationary-piece and crossing-path cases. +func chess960CastlePathClear(b *Board, kingFrom, kingTo, rookFrom, rookTo Square) bool { + return pathBetweenClear(b, kingFrom, kingTo, rookFrom) && + pathBetweenClear(b, rookFrom, rookTo, kingFrom) +} + +// pathBetweenClear reports whether every square strictly between from and to +// (exclusive) on their shared rank is empty, ignoring the exempt square (the +// other castling piece, which is permitted to occupy the path). +func pathBetweenClear(b *Board, from, to, exempt Square) bool { + lo, hi := int(from.File()), int(to.File()) + if lo > hi { + lo, hi = hi, lo + } + rank := from.Rank() + for f := lo + 1; f < hi; f++ { + sq := NewSquare(File(f), rank) + if sq == exempt { + continue + } + if b.isOccupied(sq) { + return false + } + } + return true +} + +// chess960KingTransitSafe reports whether the king can castle from kingFrom to +// kingTo: it must not be in check, and no square from kingFrom through kingTo +// (inclusive) may be attacked by the enemy. +func chess960KingTransitSafe(pos *Position, kingFrom, kingTo Square) bool { + if pos.inCheck { + return false + } + lo, hi := int(kingFrom.File()), int(kingTo.File()) + if lo > hi { + lo, hi = hi, lo + } + rank := kingFrom.Rank() + var transit []Square + for f := lo; f <= hi; f++ { + transit = append(transit, NewSquare(File(f), rank)) + } + return !squaresAreAttacked(pos, transit...) +} diff --git a/chess960_test.go b/chess960_test.go new file mode 100644 index 00000000..7519d8a4 --- /dev/null +++ b/chess960_test.go @@ -0,0 +1,693 @@ +package chess + +import ( + "strings" + "testing" +) + +// rank1BackRank returns the piece types on rank 1 indexed by file 0..7. +func rank1BackRank(b *Board) [8]PieceType { + var r [8]PieceType + for f := range 8 { + r[f] = b.Piece(NewSquare(File(f), Rank1)).Type() + } + return r +} + +func TestChess960SetupAllIndicesValid(t *testing.T) { + seen := make(map[string]struct{}, 960) + for i := range 960 { + s, err := Chess960Setup(i) + if err != nil { + t.Fatalf("Chess960Setup(%d): unexpected error: %v", i, err) + } + if s.Variant != Chess960 { + t.Errorf("index %d: Variant = %v, want Chess960", i, s.Variant) + } + pos, err := NewPosition(s) + if err != nil { + t.Errorf("index %d: NewPosition failed: %v", i, err) + continue + } + + // Two rooks on rank 1 with the king strictly between them, and the two + // bishops on opposite-colored squares. + var kingFile, bishopA, bishopB int = -1, -1, -1 + var rookFiles [2]int + ri := 0 + for f := range 8 { + pt := pos.Board().Piece(NewSquare(File(f), Rank1)).Type() + switch pt { + case King: + kingFile = f + case Rook: + if ri >= 2 { + t.Fatalf("index %d: more than two rooks on rank 1", i) + } + rookFiles[ri] = f + ri++ + case Bishop: + if bishopA < 0 { + bishopA = f + } else { + bishopB = f + } + } + } + if ri != 2 { + t.Errorf("index %d: want two rooks on rank 1, got %d", i, ri) + continue + } + if !(rookFiles[0] < kingFile && kingFile < rookFiles[1]) { + t.Errorf("index %d: king file %d not strictly between rooks %d and %d", i, kingFile, rookFiles[0], rookFiles[1]) + } + if bishopA%2 == bishopB%2 { + t.Errorf("index %d: bishops on files %d and %d are not on opposite colors", i, bishopA, bishopB) + } + + // Every index must map to a unique starting arrangement. + key := pos.Board().String() + if _, dup := seen[key]; dup { + t.Errorf("index %d: duplicate starting arrangement %q", i, key) + } + seen[key] = struct{}{} + } + if len(seen) != 960 { + t.Errorf("unique starts = %d, want 960", len(seen)) + } +} + +func TestChess960SetupIndex518IsStandard(t *testing.T) { + s, err := Chess960Setup(518) + if err != nil { + t.Fatalf("Chess960Setup(518): %v", err) + } + pos, err := NewPosition(s) + if err != nil { + t.Fatalf("NewPosition: %v", err) + } + std := StartingPosition() + want := rank1BackRank(std.Board()) + got := rank1BackRank(pos.Board()) + // SP-518 is the standard arrangement R N B Q K B N R. + if got != want { + t.Errorf("SP-518 rank 1 = %v, want standard %v", got, want) + } +} + +func TestChess960SetupOutOfRange(t *testing.T) { + for _, idx := range []int{-1, 960, 1000} { + if _, err := Chess960Setup(idx); err == nil { + t.Errorf("Chess960Setup(%d): want error, got nil", idx) + } + } +} + +func TestChess960SetupFullBoardShape(t *testing.T) { + // A starting position has a mirrored black back rank on rank 8 and pawns + // on ranks 2 and 7. + pos, err := NewPosition(mustChess960Setup(t, 0)) + if err != nil { + t.Fatalf("NewPosition: %v", err) + } + for f := range 8 { + w := pos.Board().Piece(NewSquare(File(f), Rank1)) + b := pos.Board().Piece(NewSquare(File(f), Rank8)) + if w.Type() != b.Type() { + t.Errorf("file %d: white %v != black %v on mirrored back ranks", f, w, b) + } + if pos.Board().Piece(NewSquare(File(f), Rank2)) != WhitePawn { + t.Errorf("file %d: missing white pawn on rank 2", f) + } + if pos.Board().Piece(NewSquare(File(f), Rank7)) != BlackPawn { + t.Errorf("file %d: missing black pawn on rank 7", f) + } + } +} + +func mustChess960Setup(t *testing.T, index int) Setup { + t.Helper() + s, err := Chess960Setup(index) + if err != nil { + t.Fatalf("Chess960Setup(%d): %v", index, err) + } + return s +} + +// shredderRights builds the Shredder-FEN castling rights string for a starting +// position's board: uppercase file letters for white rooks, lowercase for black. +func shredderRights(b *Board) string { + var out []byte + for f := range 8 { + if b.Piece(NewSquare(File(f), Rank1)) == WhiteRook { + out = append(out, byte('A'+f)) + } + if b.Piece(NewSquare(File(f), Rank8)) == BlackRook { + out = append(out, byte('a'+f)) + } + } + if len(out) == 0 { + return "-" + } + return string(out) +} + +func TestFENCHess960RightsInferVariant(t *testing.T) { + for _, idx := range []int{0, 1, 2, 314, 517, 518, 519, 958, 959} { + s := mustChess960Setup(t, idx) + shredder := shredderRights(&s.Board) + fen := s.Board.String() + " w " + shredder + " - 0 1" + setup, err := decodeFENSetup(fen) + if err != nil { + t.Errorf("idx %d: decodeFENSetup(%q): %v", idx, fen, err) + continue + } + if setup.Variant != Chess960 { + t.Errorf("idx %d: Variant = %v, want Chess960 (rights %q)", idx, setup.Variant, shredder) + } + want := NewCastleRights(true, true, true, true) + if setup.CastleRights != want { + t.Errorf("idx %d: CastleRights = %v, want full rights (rights %q)", idx, setup.CastleRights, shredder) + } + } +} + +func TestFENStandardRightsInferStandard(t *testing.T) { + cases := []string{ + "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w - - 0 1", + "8/8/8/8/8/8/8/4K2k w - - 0 1", + } + for _, fen := range cases { + setup, err := decodeFENSetup(fen) + if err != nil { + t.Errorf("decodeFENSetup(%q): %v", fen, err) + continue + } + if setup.Variant != Standard { + t.Errorf("decodeFENSetup(%q): Variant = %v, want Standard", fen, setup.Variant) + } + } +} + +func TestFormCastleRightsWithVariantMapping(t *testing.T) { + // Standard back rank: king e1 (file 4), rooks a1 (0) and h1 (7). + std := StartingPosition() + board := std.Board() + cr, variant, err := formCastleRightsWithVariant("AH", board) + if err != nil { + t.Fatalf("formCastleRightsWithVariant(AH): %v", err) + } + if variant != Chess960 { + t.Errorf("variant = %v, want Chess960", variant) + } + // File A (0) < king file (4) => queenside; file H (7) > king file => kingside. + if !cr.CanCastle(White, QueenSide) || !cr.CanCastle(White, KingSide) { + t.Errorf("white rights = %v, want both sides", cr) + } + if cr.CanCastle(Black, KingSide) || cr.CanCastle(Black, QueenSide) { + t.Errorf("black rights set unexpectedly: %v", cr) + } + + // '-' yields no rights and Standard. + cr, variant, err = formCastleRightsWithVariant("-", board) + if err != nil || variant != Standard || cr != (CastleRights{}) { + t.Errorf("'-' => cr=%v variant=%v err=%v, want empty/Standard/nil", cr, variant, err) + } + + // Invalid character is rejected. + if _, _, err := formCastleRightsWithVariant("AX", board); err == nil { + t.Errorf("formCastleRightsWithVariant(AX): want error, got nil") + } +} + +func TestChess960FENRoundTrip(t *testing.T) { + for i := range 960 { + pos, err := NewPosition(mustChess960Setup(t, i)) + if err != nil { + t.Fatalf("idx %d: NewPosition: %v", i, err) + } + fen := pos.String() + pos2, err := decodeFEN(fen) + if err != nil { + t.Errorf("idx %d: decodeFEN(%q): %v", i, fen, err) + continue + } + if pos2.Variant() != Chess960 { + t.Errorf("idx %d: round-trip Variant = %v, want Chess960 (fen %q)", i, pos2.Variant(), fen) + } + if pos2.CastleRights() != pos.CastleRights() { + t.Errorf("idx %d: round-trip rights %v != %v (fen %q)", i, pos2.CastleRights(), pos.CastleRights(), fen) + } + if pos2.Board().String() != pos.Board().String() { + t.Errorf("idx %d: round-trip board changed (fen %q)", i, fen) + } + } +} + +func TestStandardFENByteIdentical(t *testing.T) { + want := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" + if got := StartingPosition().String(); got != want { + t.Errorf("standard String() = %q, want %q", got, want) + } +} + +func TestChess960PerftSP518MatchesStandard(t *testing.T) { + // SP-518 is the standard starting position; the Chess960 move-generation and + // application paths must reproduce the canonical perft node counts exactly. + pos, err := NewPosition(mustChess960Setup(t, 518)) + if err != nil { + t.Fatal(err) + } + cases := []struct { + depth int + want uint64 + }{ + {1, 20}, + {2, 400}, + {3, 8902}, + {4, 197281}, + } + for _, c := range cases { + if got := pos.Perft(c.depth); got != c.want { + t.Errorf("SP-518 perft(%d) = %d, want %d", c.depth, got, c.want) + } + } +} + +func TestChess960PerftAllStartsNoCrash(t *testing.T) { + // Exercises the full make/unmake castling path across every indexed start. + for i := range 960 { + pos, err := NewPosition(mustChess960Setup(t, i)) + if err != nil { + t.Fatalf("idx %d: %v", i, err) + } + if n := pos.Perft(2); n == 0 { + t.Errorf("idx %d: perft(2) = 0", i) + } + } +} + +func TestChess960CastlingKingSide(t *testing.T) { + // White king on c1, rooks on a1 (queen side) and e1 (king side). King-side + // castle moves the king c1->g1 and the rook e1->f1; only Shredder rights are + // present, so this also exercises variant inference. + pos, err := decodeFEN("4k3/8/8/8/8/8/8/R2KR3 w EA - 0 1") + if err != nil { + t.Fatalf("decodeFEN: %v", err) + } + if pos.Variant() != Chess960 { + t.Fatalf("variant = %v, want Chess960", pos.Variant()) + } + var castle Move + found := false + for _, m := range pos.ValidMoves() { + if m.HasTag(KingSideCastle) { + castle = m + found = true + } + } + if !found { + t.Fatal("no king-side castle move generated") + } + if castle.S1() != D1 || castle.S2() != G1 { + t.Errorf("castle = %s%s, want d1g1", castle.S1(), castle.S2()) + } + if san := (algebraicNotation{}).Encode(pos, castle); san != "O-O" { + t.Errorf("SAN = %q, want O-O", san) + } + pos2 := pos.Update(castle) + if pos2.Board().Piece(G1) != WhiteKing { + t.Errorf("g1 = %v, want WhiteKing", pos2.Board().Piece(G1)) + } + if pos2.Board().Piece(F1) != WhiteRook { + t.Errorf("f1 = %v, want WhiteRook", pos2.Board().Piece(F1)) + } + if pos2.Board().Piece(E1) != NoPiece { + t.Errorf("e1 = %v, want empty after rook moves", pos2.Board().Piece(E1)) + } + if pos2.Board().Piece(D1) != NoPiece { + t.Errorf("d1 = %v, want empty after king moves", pos2.Board().Piece(D1)) + } + if pos2.CastleRights().CanCastle(White, KingSide) { + t.Error("king-side right not consumed") + } + if pos2.CastleRights().CanCastle(White, QueenSide) { + t.Error("king move should also consume the queen-side right") + } +} + +func TestChess960PGNRoundTrip(t *testing.T) { + // Build a Chess960 game from a non-standard start, render to PGN, and + // reparse: the variant and starting position must survive the round trip. + pos, err := NewPosition(mustChess960Setup(t, 247)) + if err != nil { + t.Fatal(err) + } + opt, err := FEN(pos.String()) + if err != nil { + t.Fatalf("FEN option: %v", err) + } + g := NewGame(opt) + if g.Variant() != Chess960 { + t.Fatalf("game variant = %v, want Chess960", g.Variant()) + } + pgn := g.String() + if !strings.Contains(pgn, `[Variant "Chess960"]`) { + t.Errorf("PGN missing [Variant \"Chess960\"]:\n%s", pgn) + } + if !strings.Contains(pgn, `[SetUp "1"]`) { + t.Errorf("PGN missing [SetUp \"1\"]:\n%s", pgn) + } + g2, err := ParsePGN(strings.NewReader(pgn)) + if err != nil { + t.Fatalf("reparse PGN: %v\n%s", err, pgn) + } + if g2.Variant() != Chess960 { + t.Errorf("round-trip variant = %v, want Chess960", g2.Variant()) + } +} + +func TestChess960PGNVariantTagAlias(t *testing.T) { + // The "Fischer Random" alias must select the Chess960 variant, and a Shredder + // FEN reconstructs the start. + pgn := `[Variant "Fischer Random"]` + "\n" + + `[SetUp "1"]` + "\n" + + `[FEN "rnbkrqnb/pppppppp/8/8/8/8/PPPPPPPP/RNBKRQNB w AEae - 0 1"]` + "\n\n*\n" + g, err := ParsePGN(strings.NewReader(pgn)) + if err != nil { + t.Fatalf("ParsePGN: %v", err) + } + if g.Variant() != Chess960 { + t.Errorf("variant = %v, want Chess960", g.Variant()) + } +} + +func TestStandardPGNHasNoVariantTag(t *testing.T) { + if strings.Contains(NewGame().String(), "Variant") { + t.Error("standard game PGN should not contain a Variant tag") + } +} + +func TestChess960BinaryRoundTrip(t *testing.T) { + pos, err := NewPosition(mustChess960Setup(t, 500)) + if err != nil { + t.Fatal(err) + } + data, err := pos.MarshalBinary() + if err != nil { + t.Fatalf("MarshalBinary: %v", err) + } + if len(data) != 101 { + t.Errorf("binary size = %d, want 101", len(data)) + } + var pos2 Position + if err := pos2.UnmarshalBinary(data); err != nil { + t.Fatalf("UnmarshalBinary: %v", err) + } + if pos2.Variant() != Chess960 { + t.Errorf("round-trip variant = %v, want Chess960", pos2.Variant()) + } + if pos2.ZobristHash() != pos.ZobristHash() { + t.Errorf("hash mismatch: %d != %d", pos2.ZobristHash(), pos.ZobristHash()) + } +} + +// TestChess960CastlingEdgeCases covers the geometric case classes the castling +// move generator must handle: a king whose path crosses the rook destination +// (queenside, king h1, rook a1), a stationary rook (kingside, rook already +// on f1), the king-adjacent-to-destination case (king f1, rook h1), and a +// kingside path blocked by a non-castling piece. Positions are built via +// Setup so the board placement is unambiguous; the resulting position's FEN +// still round-trips through decodeFEN, so the same machinery the rest of the +// library uses is exercised. +func TestChess960CastlingEdgeCases(t *testing.T) { + type want struct { + legal bool + side MoveTag // KingSideCastle or QueenSideCastle (ignored when !legal) + kingFrom Square + kingTo Square + rookFrom Square + rookTo Square + } + + cases := []struct { + name string + set Setup + want want + }{ + { + // King h1 with queen-side rook on a1. King's transit h1->c1 covers + // g1,f1,e1,d1; the rook's destination d1 lies on the king's + // transit — a king-path-contains-rook-destination crossing. + name: "king_h1_queenside_crossing", + set: makeChess960Set(t, + map[Square]Piece{H1: WhiteKing, A1: WhiteRook, A8: BlackRook, E8: BlackKing}, + NewCastleRights(false, true, false, false), + ), + want: want{legal: true, side: QueenSideCastle, kingFrom: H1, kingTo: C1, rookFrom: A1, rookTo: D1}, + }, + { + name: "stationary_rook_kingside", + set: makeChess960Set(t, + map[Square]Piece{B1: WhiteKing, F1: WhiteRook, A8: BlackRook, E8: BlackKing}, + NewCastleRights(true, false, false, false), + ), + want: want{legal: true, side: KingSideCastle, kingFrom: B1, kingTo: G1, rookFrom: F1, rookTo: F1}, + }, + { + name: "king_adjacent_kingside", + set: makeChess960Set(t, + map[Square]Piece{F1: WhiteKing, H1: WhiteRook, A8: BlackRook, E8: BlackKing}, + NewCastleRights(true, false, false, false), + ), + want: want{legal: true, side: KingSideCastle, kingFrom: F1, kingTo: G1, rookFrom: H1, rookTo: F1}, + }, + { + // Blocked: bishop on e1 sits on the kingside transit of king a1 + // with the kingside rook on h1; no kingside castle should be legal. + name: "blocked_kingside_no_castle", + set: makeChess960Set(t, + map[Square]Piece{A1: WhiteKing, H1: WhiteRook, E1: WhiteBishop, H8: BlackRook, A8: BlackRook, E8: BlackKing}, + NewCastleRights(true, false, false, false), + ), + want: want{legal: false, side: KingSideCastle}, + }, + } + for _, tc := range cases { + t.Run(tc.name, func(t *testing.T) { + pos, err := NewPosition(tc.set) + if err != nil { + t.Fatalf("NewPosition: %v", err) + } + if pos.Variant() != Chess960 { + t.Fatalf("variant = %v, want Chess960", pos.Variant()) + } + // Round-trip through FEN to exercise the same codecs the library uses. + fen := pos.String() + pos, err = decodeFEN(fen) + if err != nil { + t.Fatalf("round-trip decodeFEN(%q): %v", fen, err) + } + var castle Move + seen := false + for _, m := range pos.ValidMoves() { + if m.HasTag(tc.want.side) { + castle, seen = m, true + } + } + if !tc.want.legal { + if seen { + t.Errorf("castle move generated, want none: %s%s", castle.S1(), castle.S2()) + } + return + } + if !seen { + // Fall back: scan for either castle tag. + for _, m := range pos.ValidMoves() { + if m.HasTag(KingSideCastle) || m.HasTag(QueenSideCastle) { + castle, seen = m, true + break + } + } + if !seen { + t.Fatal("no castle move generated") + } + } + if castle.S1() != tc.want.kingFrom || castle.S2() != tc.want.kingTo { + t.Errorf("king %s%s, want %s%s", castle.S1(), castle.S2(), tc.want.kingFrom, tc.want.kingTo) + } + pos2 := pos.Update(castle) + if pos2.Board().Piece(tc.want.kingTo) != WhiteKing { + t.Errorf("%s = %v, want WhiteKing", tc.want.kingTo, pos2.Board().Piece(tc.want.kingTo)) + } + if pos2.Board().Piece(tc.want.rookTo) != WhiteRook { + t.Errorf("%s = %v, want WhiteRook", tc.want.rookTo, pos2.Board().Piece(tc.want.rookTo)) + } + if tc.want.rookFrom != tc.want.rookTo && pos2.Board().Piece(tc.want.rookFrom) != NoPiece { + t.Errorf("%s = %v, want empty", tc.want.rookFrom, pos2.Board().Piece(tc.want.rookFrom)) + } + }) + } +} + +// makeChess960Set builds a Setup from a piece map (any subset of the board), +// with the castling rights provided, fullmove number set to 1, and variant +// set to Chess960. Rank 1 and rank 8 pieces intended for the opponent must +// be included explicitly in the map. +func makeChess960Set(t *testing.T, pieces map[Square]Piece, rights CastleRights) Setup { + t.Helper() + b, err := NewBoard(pieces) + if err != nil { + t.Fatalf("makeChess960Set: NewBoard: %v", err) + } + return Setup{ + Board: *b, + Turn: White, + CastleRights: rights, + EnPassant: NoSquare, + FullMoveNo: 1, + Variant: Chess960, + } +} + +// TestFormCastleRightsWithVariantRejectsOrphanedFile ensures a Shredder rights +// string whose named file has no rook on the back rank is rejected at parse +// time rather than silently dropping the right. The king on c1 with rooks on +// a1 and e1 cannot have rights "CH" (c1 has no rook, h1 has no rook). +func TestFormCastleRightsWithVariantRejectsOrphanedFile(t *testing.T) { + pos := StartingPosition() + for _, rights := range []string{"CH", "DA", "Ax"} { + if _, _, err := formCastleRightsWithVariant(rights, pos.Board()); err == nil { + t.Errorf("formCastleRightsWithVariant(%q): want error, got nil", rights) + } + } + if _, _, err := formCastleRightsWithVariant("-", pos.Board()); err != nil { + t.Errorf("formCastleRightsWithVariant(-): %v", err) + } +} + +// TestUCIEncodeChess960CastleKingToRook verifies that UCI castling in a +// Chess960 position is encoded king-to-rook (e.g. "e1h1"), the form engines +// expect when the UCI_Chess960 option is set. SP-518 is the standard +// arrangement marked Chess960: king e1, rooks a1/h1. +func TestUCIEncodeChess960CastleKingToRook(t *testing.T) { + pos, err := NewPosition(mustChess960Setup(t, 518)) + if err != nil { + t.Fatalf("NewPosition: %v", err) + } + for _, tc := range []struct { + name string + m Move + want string + }{ + {"kingside", Move{s1: E1, s2: G1, tags: KingSideCastle}, "e1h1"}, + {"queenside", Move{s1: E1, s2: C1, tags: QueenSideCastle}, "e1a1"}, + } { + t.Run(tc.name, func(t *testing.T) { + got, err := UCI().Encode(pos, tc.m) + if err != nil { + t.Fatalf("Encode: %v", err) + } + if got != tc.want { + t.Errorf("Encode(%v) = %q, want %q", tc.m, got, tc.want) + } + }) + } +} + +// TestUCIEncodeChess960CastleNonStandardRook checks a Chess960 position whose +// castling rook is not on a1/h1: king c1 with the king-side rook on h1 encodes +// the castle as "c1h1", not the king's destination "c1g1". +func TestUCIEncodeChess960CastleNonStandardRook(t *testing.T) { + pos, err := NewPosition(makeChess960Set(t, map[Square]Piece{ + C1: WhiteKing, H1: WhiteRook, E8: BlackKing, + }, NewCastleRights(true, false, false, false))) + if err != nil { + t.Fatalf("NewPosition: %v", err) + } + got, err := UCI().Encode(pos, Move{s1: C1, s2: G1, tags: KingSideCastle}) + if err != nil { + t.Fatalf("Encode: %v", err) + } + if got != "c1h1" { + t.Errorf("Encode = %q, want %q", got, "c1h1") + } +} + +// TestUCIDecodeChess960AcceptsBothCastleForms verifies the codec reads both the +// king-to-rook form ("c1h1", from UCI_Chess960 engines) and the +// king-to-destination form ("c1g1", legacy) as the same canonical castle. +func TestUCIDecodeChess960AcceptsBothCastleForms(t *testing.T) { + pos, err := NewPosition(makeChess960Set(t, map[Square]Piece{ + C1: WhiteKing, H1: WhiteRook, B8: BlackKing, + }, NewCastleRights(true, false, false, false))) + if err != nil { + t.Fatalf("NewPosition: %v", err) + } + for _, tc := range []struct { + name string + in string + }{ + {"king-to-rook", "c1h1"}, + {"king-to-destination", "c1g1"}, + } { + t.Run(tc.name, func(t *testing.T) { + m, err := UCI().Decode(pos, tc.in) + if err != nil { + t.Fatalf("Decode(%q): %v", tc.in, err) + } + if m.S1() != C1 || m.S2() != G1 { + t.Errorf("Decode(%q) = %v-%v, want c1-g1", tc.in, m.S1(), m.S2()) + } + if !m.HasTag(KingSideCastle) { + t.Errorf("Decode(%q): missing KingSideCastle tag", tc.in) + } + }) + } +} + +// TestUCIEncodeStandardCastleIsKingToDestination guards the standard-variant +// path: even with castling tags, a Standard position emits the king's +// destination square (e1g1), never king-to-rook. +func TestUCIEncodeStandardCastleIsKingToDestination(t *testing.T) { + pos := unsafeFEN("r3k2r/8/8/8/8/8/8/R3K2R w KQkq - 0 1") + got, err := UCI().Encode(pos, Move{s1: E1, s2: G1, tags: KingSideCastle}) + if err != nil { + t.Fatalf("Encode: %v", err) + } + if got != "e1g1" { + t.Errorf("Encode = %q, want %q (standard must stay king-to-destination)", got, "e1g1") + } +} + +// TestUCIDecodeChess960QueenSideCastleForms verifies both Chess960 UCI +// spellings resolve a queen-side castle whose rook is left of the king. +func TestUCIDecodeChess960QueenSideCastleForms(t *testing.T) { + pos, err := NewPosition(makeChess960Set(t, map[Square]Piece{ + B1: WhiteRook, F1: WhiteKing, H8: BlackKing, + }, NewCastleRights(false, true, false, false))) + if err != nil { + t.Fatalf("NewPosition: %v", err) + } + for _, tc := range []struct { + name string + in string + }{ + {"king-to-rook", "f1b1"}, + {"king-to-destination", "f1c1"}, + } { + t.Run(tc.name, func(t *testing.T) { + m, err := UCI().Decode(pos, tc.in) + if err != nil { + t.Fatalf("Decode(%q): %v", tc.in, err) + } + if m.S1() != F1 || m.S2() != C1 { + t.Errorf("Decode(%q) = %v-%v, want f1-c1", tc.in, m.S1(), m.S2()) + } + if !m.HasTag(QueenSideCastle) { + t.Errorf("Decode(%q): missing QueenSideCastle tag", tc.in) + } + }) + } +} diff --git a/cog.toml b/cog.toml deleted file mode 100644 index 0c186c81..00000000 --- a/cog.toml +++ /dev/null @@ -1,26 +0,0 @@ -from_latest_tag = true -ignore_merge_commits = false -tag_prefix = "v" -disable_changelog = false -disable_bump_commit = false -generate_mono_repository_global_tag = true -generate_mono_repository_package_tags = true -branch_whitelist = [] -skip_ci = "[skip ci]" -skip_untracked = false -pre_bump_hooks = [] -post_bump_hooks = [] -pre_package_bump_hooks = [] -post_package_bump_hooks = [] - -[git_hooks] - -[commit_types] - -[changelog] -path = "CHANGELOG.md" -authors = [] - -[bump_profiles] - -[packages] diff --git a/coverage.out b/coverage.out deleted file mode 100644 index c97d24ba..00000000 --- a/coverage.out +++ /dev/null @@ -1,2186 +0,0 @@ -mode: set -github.com/corentings/chess/v2/uci/adapter.go:22.68,24.16 2 0 -github.com/corentings/chess/v2/uci/adapter.go:24.16,26.3 1 0 -github.com/corentings/chess/v2/uci/adapter.go:27.2,32.36 6 0 -github.com/corentings/chess/v2/uci/adapter.go:32.36,34.3 1 0 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accomplish the following: - - chess game / turn management + - chess game state and move tree management - move validation - PGN encoding / decoding - FEN encoding / decoding +Game values are mutable and are not safe for concurrent use by multiple +goroutines. Callers that share a Game between goroutines must provide their own +synchronization. + Using Moves game := chess.NewGame() moves := game.ValidMoves() - game.Move(moves[0]) + game.Move(moves[0], nil) -Using Algebraic Notation +Using Strict SAN Move Text game := chess.NewGame() - game.MoveStr("e4") + game.MoveText("e4", SAN(), nil) Using PGN - pgn, _ := chess.PGN(pgnReader) - game := chess.NewGame(pgn) + game, _ := chess.ParsePGN(pgnReader) Using FEN @@ -32,9 +35,9 @@ Random Game import ( "fmt" - "math/rand" + "math/rand/v2" - "github.com/corentings/chess/v2" + "github.com/corentings/chess/v3" ) func main() { @@ -43,8 +46,8 @@ Random Game for game.Outcome() == chess.NoOutcome { // select a random move moves := game.ValidMoves() - move := moves[rand.Intn(len(moves))] - game.Move(move) + move := moves[rand.IntN(len(moves))] + game.Move(move, nil) } // print outcome and game PGN fmt.Println(game.Position().Board().Draw()) diff --git a/engine.go b/engine.go deleted file mode 100644 index 35f8bdba..00000000 --- a/engine.go +++ /dev/null @@ -1,518 +0,0 @@ -/* -Package chess implements a chess game engine that manages move generation, -position analysis, and game state validation. -The engine uses bitboard operations and lookup tables for efficient move -generation and position analysis. Move generation includes standard piece -moves, captures, castling, en passant, and pawn promotions. -Example usage: - - // Create a position - pos := NewPosition() - - // Calculate legal moves for current position - eng := engine{} - moves := eng.CalcMoves(pos, false) - - // Check game status - status := eng.Status(pos) - if status == Checkmate { - fmt.Println("Game Over - Checkmate") - } -*/ -package chess - -import "sync" - -// engine implements chess move generation and position analysis. -type engine struct{} - -// CalcMoves returns all legal moves for the given position. If first is true, -// returns after finding the first legal move. This is useful for quick position -// validation. -// -// The moves are generated in the following order: -// 1. Standard piece moves and captures -// 2. Castling moves (if available) -// -// Each move is validated to ensure it doesn't leave the king in check -func (engine) CalcMoves(pos *Position, first bool) []Move { - // generate possible moves - moves := standardMoves(pos, first, false) - // return moves including castles - return append(moves, castleMoves(pos)...) -} - -// UnsafeMoves returns all pseudo-legal moves that are illegal because they -// leave the moving side's king in check. -func (engine) UnsafeMoves(pos *Position) []Move { - return standardMoves(pos, false, true) -} - -// Status returns the current game status (Checkmate, Stalemate, or NoMethod) -// based on the position. -// -// The status is determined by: -// - Whether the side to move is in check -// - Whether any legal moves exist -// -// If the position has cached valid moves in pos.validMoves, those will be -// used. Otherwise, moves will be calculated to determine the status. -func (engine) Status(pos *Position) Method { - var hasMove bool - if pos.validMoves != nil { - hasMove = len(pos.validMoves) > 0 - } else { - hasMove = len(engine{}.CalcMoves(pos, true)) > 0 - } - if !pos.inCheck && !hasMove { - return Stalemate - } else if pos.inCheck && !hasMove { - return Checkmate - } - return NoMethod -} - -// promoPieceTypes is an immutable array of promotion piece types. -// Treat as read-only; do not modify elements. -// -//nolint:gochecknoglobals // Immutable lookup table. -var promoPieceTypes = [4]PieceType{Queen, Rook, Bishop, Knight} - -const maxPossibleMoves = 218 // Maximum possible moves in any chess position - -// movePool is a pool of Move arrays to reduce allocations -// in the standardMoves function. -// -//nolint:gochecknoglobals // this is a sync pool -var movePool = sync.Pool{ - New: func() interface{} { - return &[maxPossibleMoves]Move{} - }, -} - -// standardMoves generates all standard (non-castling) legal moves for the -// current position. If first is true, returns after finding the first -// legal move. -// -// The function uses a sync.Pool of move arrays to reduce allocations. Each -// move is validated to ensure it doesn't leave the king in check. -func standardMoves(pos *Position, first bool, unsafeOnly bool) []Move { - moves, _ := movePool.Get().(*[maxPossibleMoves]Move) - defer movePool.Put(moves) - count := 0 - - // Reuse a single Move struct for temporary operations - var m Move - - bbAllowed := ^pos.board.whiteSqs - if pos.Turn() == Black { - bbAllowed = ^pos.board.blackSqs - } - - for _, p := range allPieces { - if pos.Turn() != p.Color() { - continue - } - s1BB := pos.board.bbForPiece(p) - if s1BB == 0 { - continue - } - for s1 := range numOfSquaresInBoard { - if s1BB&bbForSquare(Square(s1)) == 0 { - continue - } - s2BB := bbForPossibleMoves(pos, p.Type(), Square(s1)) & bbAllowed - if s2BB == 0 { - continue - } - for s2 := range numOfSquaresInBoard { - if s2BB&bbForSquare(Square(s2)) == 0 { - continue - } - - // Reuse move struct by setting fields directly - m.s1 = Square(s1) - m.s2 = Square(s2) - - if (p == WhitePawn && Square(s2).Rank() == Rank8) || (p == BlackPawn && Square(s2).Rank() == Rank1) { - for _, pt := range promoPieceTypes { - m.promo = pt - m.tags = moveTags(m, pos) - if m.HasTag(inCheck) == unsafeOnly { - // Copy the valid move to the array - moves[count] = m - count++ - if first { - // For single move, return fixed array of size 1 - var result [1]Move - result[0] = moves[0] - return result[:] - } - } - } - } else { - m.promo = 0 - m.tags = moveTags(m, pos) - if m.HasTag(inCheck) == unsafeOnly { - moves[count] = m - count++ - if first { - var result [1]Move - result[0] = moves[0] - return result[:] - } - } - } - } - } - } - - // Need to copy since we're returning array to pool - result := make([]Move, count) - copy(result, moves[:count]) - return result -} - -// moveTags computes all tags for a move from scratch based on the resulting position. -// Tags include: -// - Capture: The move captures an opponent's piece -// - EnPassant: The move is an en passant capture -// - Check: The move puts the opponent in check -// - inCheck: The move leaves the moving side's king in check (illegal) -// - KingSideCastle: The move is a king-side castle -// - QueenSideCastle: The move is a queen-side castle -func moveTags(m Move, pos *Position) MoveTag { - var tags MoveTag - p := pos.board.Piece(m.s1) - if pos.board.isOccupied(m.s2) { - tags |= Capture - } else if m.s2 == pos.enPassantSquare && p.Type() == Pawn { - tags |= EnPassant - } - // determine if move is castle - if (p == WhiteKing && m.s1 == E1) || (p == BlackKing && m.s1 == E8) { - switch m.s2 { - case C1, C8: - tags |= QueenSideCastle - case G1, G8: - tags |= KingSideCastle - } - } - // apply preliminary tags to a local copy so board.update reads them correctly - local := m - local.tags = tags - // determine if in check after move (makes move invalid) - // Simulate the move on a temporary board copy so we can test - // check status without mutating the actual position. - tempBoard := *pos.board - tempBoard.update(&local) - if tempBoard.kingSquare(pos.turn) != NoSquare { - if isSquareAttackedBy(&tempBoard, tempBoard.kingSquare(pos.turn), pos.turn.Other()) { - tags |= inCheck - } - } - // determine if opponent in check after move - if tempBoard.kingSquare(pos.turn.Other()) != NoSquare { - if isSquareAttackedBy(&tempBoard, tempBoard.kingSquare(pos.turn.Other()), pos.turn) { - tags |= Check - } - } - return tags -} - -// isInCheck returns true if the side to move is in check in the given position. -func isInCheck(pos *Position) bool { - kingSq := pos.board.kingSquare(pos.Turn()) - // king should only be missing in tests / examples - if kingSq == NoSquare { - return false - } - return squaresAreAttacked(pos, kingSq) -} - -// isSquareAttackedBy returns true if the given square is attacked by the specified color. -// This is a board-level operation that does not require a full Position. -// -//nolint:mnd // this is a formula to determine if a square is attacked -func isSquareAttackedBy(board *Board, sq Square, attacker Color) bool { - occ := ^board.emptySqs - - // hot path check to see if attack vector is possible - s2BB := board.blackSqs - if attacker == White { - s2BB = board.whiteSqs - } - if ((diaAttack(occ, sq)|hvAttack(occ, sq))&s2BB)|(bbKnightMoves[sq]&s2BB) == 0 { - return false - } - - // check queen attack vector - queenBB := board.bbForPiece(NewPiece(Queen, attacker)) - bb := (diaAttack(occ, sq) | hvAttack(occ, sq)) & queenBB - if bb != 0 { - return true - } - // check rook attack vector - rookBB := board.bbForPiece(NewPiece(Rook, attacker)) - bb = hvAttack(occ, sq) & rookBB - if bb != 0 { - return true - } - // check bishop attack vector - bishopBB := board.bbForPiece(NewPiece(Bishop, attacker)) - bb = diaAttack(occ, sq) & bishopBB - if bb != 0 { - return true - } - // check knight attack vector - knightBB := board.bbForPiece(NewPiece(Knight, attacker)) - bb = bbKnightMoves[sq] & knightBB - if bb != 0 { - return true - } - // check pawn attack vector - if attacker == Black { - capRight := (board.bbBlackPawn & ^bbFileH & ^bbRank1) << 7 - capLeft := (board.bbBlackPawn & ^bbFileA & ^bbRank1) << 9 - bb = (capRight | capLeft) & bbForSquare(sq) - if bb != 0 { - return true - } - } else { - capRight := (board.bbWhitePawn & ^bbFileH & ^bbRank8) >> 9 - capLeft := (board.bbWhitePawn & ^bbFileA & ^bbRank8) >> 7 - bb = (capRight | capLeft) & bbForSquare(sq) - if bb != 0 { - return true - } - } - // check king attack vector - kingBB := board.bbForPiece(NewPiece(King, attacker)) - bb = bbKingMoves[sq] & kingBB - return bb != 0 -} - -// squaresAreAttacked returns true if the opponent attacks any of the given squares -// -// in the given position. -// -// The function checks attacks from: -// - Sliding pieces (queen, rook, bishop) -// - Knights -// - Pawns -// - King -func squaresAreAttacked(pos *Position, sqs ...Square) bool { - otherColor := pos.Turn().Other() - for _, sq := range sqs { - if isSquareAttackedBy(pos.board, sq, otherColor) { - return true - } - } - return false -} - -// bbForPossibleMoves returns a bitboard with 1s in positions where the piece -// of the given type at the given square can potentially move, without considering -// whether the moves would be legal (e.g., leave the king in check). -// -// The function handles movement patterns for: -// - King: One square in any direction -// - Queen: Sliding moves in all directions -// - Rook: Sliding moves horizontally and vertically -// - Bishop: Sliding moves diagonally -// - Knight: L-shaped jumps -// - Pawn: Forward moves and captures, including en passant -func bbForPossibleMoves(pos *Position, pt PieceType, sq Square) bitboard { - switch pt { - case King: - return bbKingMoves[sq] - case Queen: - return diaAttack(^pos.board.emptySqs, sq) | hvAttack(^pos.board.emptySqs, sq) - case Rook: - return hvAttack(^pos.board.emptySqs, sq) - case Bishop: - return diaAttack(^pos.board.emptySqs, sq) - case Knight: - return bbKnightMoves[sq] - case Pawn: - return pawnMoves(pos, sq) - } - return bitboard(0) -} - -// castleMoves returns all legal castling moves for the current position. -// -// A castling move is legal if: -// - The king has castling rights in that direction -// - The squares between king and rook are empty -// - The king is not in check -// - The king does not pass through check -func castleMoves(pos *Position) []Move { - var moves [2]Move // Maximum of 2 possible castle moves (king side and queen side) - count := 0 - - kingSide := pos.castleRights.CanCastle(pos.Turn(), KingSide) - queenSide := pos.castleRights.CanCastle(pos.Turn(), QueenSide) - - // white king side - if pos.turn == White && kingSide && - (^pos.board.emptySqs&(bbForSquare(F1)|bbForSquare(G1))) == 0 && - !squaresAreAttacked(pos, F1, G1) && - !pos.inCheck { - m := Move{s1: E1, s2: G1} - m.tags = moveTags(m, pos) - moves[count] = m - count++ - } - - // white queen side - if pos.turn == White && queenSide && - (^pos.board.emptySqs&(bbForSquare(B1)|bbForSquare(C1)|bbForSquare(D1))) == 0 && - !squaresAreAttacked(pos, C1, D1) && - !pos.inCheck { - m := Move{s1: E1, s2: C1} - m.tags = moveTags(m, pos) - moves[count] = m - count++ - } - - // black king side - if pos.turn == Black && kingSide && - (^pos.board.emptySqs&(bbForSquare(F8)|bbForSquare(G8))) == 0 && - !squaresAreAttacked(pos, F8, G8) && - !pos.inCheck { - m := Move{s1: E8, s2: G8} - m.tags = moveTags(m, pos) - moves[count] = m - count++ - } - - // black queen side - if pos.turn == Black && queenSide && - (^pos.board.emptySqs&(bbForSquare(B8)|bbForSquare(C8)|bbForSquare(D8))) == 0 && - !squaresAreAttacked(pos, C8, D8) && - !pos.inCheck { - m := Move{s1: E8, s2: C8} - m.tags = moveTags(m, pos) - moves[count] = m - count++ - } - - return moves[:count] -} - -// pawnMoves returns a bitboard with 1s in positions where the pawn at the -// given square can potentially move. -// -// The function considers: -// - Single and double forward moves -// - Diagonal captures -// - En passant captures -// -//nolint:mnd // this is a formula to determine the color of a square -func pawnMoves(pos *Position, sq Square) bitboard { - bb := bbForSquare(sq) - var bbEnPassant bitboard - if pos.enPassantSquare != NoSquare { - bbEnPassant = bbForSquare(pos.enPassantSquare) - } - if pos.Turn() == White { - capRight := ((bb & ^bbFileH & ^bbRank8) >> 9) & (pos.board.blackSqs | bbEnPassant) - capLeft := ((bb & ^bbFileA & ^bbRank8) >> 7) & (pos.board.blackSqs | bbEnPassant) - upOne := ((bb & ^bbRank8) >> 8) & pos.board.emptySqs - upTwo := ((upOne & bbRank3) >> 8) & pos.board.emptySqs - return capRight | capLeft | upOne | upTwo - } - capRight := ((bb & ^bbFileH & ^bbRank1) << 7) & (pos.board.whiteSqs | bbEnPassant) - capLeft := ((bb & ^bbFileA & ^bbRank1) << 9) & (pos.board.whiteSqs | bbEnPassant) - upOne := ((bb & ^bbRank1) << 8) & pos.board.emptySqs - upTwo := ((upOne & bbRank6) << 8) & pos.board.emptySqs - return capRight | capLeft | upOne | upTwo -} - -// diaAttack returns a bitboard representing possible diagonal moves for a -// sliding piece, considering occupied squares as blocking further movement. -func diaAttack(occupied bitboard, sq Square) bitboard { - pos := bbForSquare(sq) - dMask := bbDiagonals[sq] - adMask := bbAntiDiagonals[sq] - return linearAttack(occupied, pos, dMask) | linearAttack(occupied, pos, adMask) -} - -// hvAttack returns a bitboard representing possible horizontal and vertical -func hvAttack(occupied bitboard, sq Square) bitboard { - pos := bbForSquare(sq) - rankMask := bbRanks[sq.Rank()] - fileMask := bbFiles[sq.File()] - return linearAttack(occupied, pos, rankMask) | linearAttack(occupied, pos, fileMask) -} - -// linearAttack returns a bitboard representing possible moves in a single -// direction (rank, file, or diagonal) for a sliding piece, considering -// occupied squares as blocking further movement. -func linearAttack(occupied, pos, mask bitboard) bitboard { - oInMask := occupied & mask - return ((oInMask - 2*pos) ^ (oInMask.Reverse() - 2*pos.Reverse()).Reverse()) & mask -} - -const ( - bbFileA bitboard = 9259542123273814144 - bbFileB bitboard = 4629771061636907072 - bbFileC bitboard = 2314885530818453536 - bbFileD bitboard = 1157442765409226768 - bbFileE bitboard = 578721382704613384 - bbFileF bitboard = 289360691352306692 - bbFileG bitboard = 144680345676153346 - bbFileH bitboard = 72340172838076673 - - bbRank1 bitboard = 18374686479671623680 - bbRank2 bitboard = 71776119061217280 - bbRank3 bitboard = 280375465082880 - bbRank4 bitboard = 1095216660480 - bbRank5 bitboard = 4278190080 - bbRank6 bitboard = 16711680 - bbRank7 bitboard = 65280 - bbRank8 bitboard = 255 -) - -// bbForSquare returns the bitboard mask for the given square. -// This is a package-level function rather than a Square method because it -// accesses the package-level lookup table bbSquares. -func bbForSquare(sq Square) bitboard { - return bbSquares[sq] -} - -// Lookup tables for piece movement patterns and board masks. -// -//nolint:gochecknoglobals // this is a lookup table -var ( - bbFiles = [8]bitboard{bbFileA, bbFileB, bbFileC, bbFileD, bbFileE, bbFileF, bbFileG, bbFileH} // bbFiles contains masks for each file (A-H) - bbRanks = [8]bitboard{bbRank1, bbRank2, bbRank3, bbRank4, bbRank5, bbRank6, bbRank7, bbRank8} // bbRanks contains masks for each rank (1-8) - - bbDiagonals = [64]bitboard{9241421688590303745, 4620710844295151872, 2310355422147575808, 1155177711073755136, 577588855528488960, 288794425616760832, 144396663052566528, 72057594037927936, 36099303471055874, 9241421688590303745, 4620710844295151872, 2310355422147575808, 1155177711073755136, 577588855528488960, 288794425616760832, 144396663052566528, 141012904183812, 36099303471055874, 9241421688590303745, 4620710844295151872, 2310355422147575808, 1155177711073755136, 577588855528488960, 288794425616760832, 550831656968, 141012904183812, 36099303471055874, 9241421688590303745, 4620710844295151872, 2310355422147575808, 1155177711073755136, 577588855528488960, 2151686160, 550831656968, 141012904183812, 36099303471055874, 9241421688590303745, 4620710844295151872, 2310355422147575808, 1155177711073755136, 8405024, 2151686160, 550831656968, 141012904183812, 36099303471055874, 9241421688590303745, 4620710844295151872, 2310355422147575808, 32832, 8405024, 2151686160, 550831656968, 141012904183812, 36099303471055874, 9241421688590303745, 4620710844295151872, 128, 32832, 8405024, 2151686160, 550831656968, 141012904183812, 36099303471055874, 9241421688590303745} - - bbAntiDiagonals = [64]bitboard{9223372036854775808, 4647714815446351872, 2323998145211531264, 1161999622361579520, 580999813328273408, 290499906672525312, 145249953336295424, 72624976668147840, 4647714815446351872, 2323998145211531264, 1161999622361579520, 580999813328273408, 290499906672525312, 145249953336295424, 72624976668147840, 283691315109952, 2323998145211531264, 1161999622361579520, 580999813328273408, 290499906672525312, 145249953336295424, 72624976668147840, 283691315109952, 1108169199648, 1161999622361579520, 580999813328273408, 290499906672525312, 145249953336295424, 72624976668147840, 283691315109952, 1108169199648, 4328785936, 580999813328273408, 290499906672525312, 145249953336295424, 72624976668147840, 283691315109952, 1108169199648, 4328785936, 16909320, 290499906672525312, 145249953336295424, 72624976668147840, 283691315109952, 1108169199648, 4328785936, 16909320, 66052, 145249953336295424, 72624976668147840, 283691315109952, 1108169199648, 4328785936, 16909320, 66052, 258, 72624976668147840, 283691315109952, 1108169199648, 4328785936, 16909320, 66052, 258, 1} - - bbKnightMoves = [64]bitboard{9077567998918656, 4679521487814656, 38368557762871296, 19184278881435648, 9592139440717824, 4796069720358912, 2257297371824128, 1128098930098176, 2305878468463689728, 1152939783987658752, 9799982666336960512, 4899991333168480256, 2449995666584240128, 1224997833292120064, 576469569871282176, 288234782788157440, 4620693356194824192, 11533718717099671552, 5802888705324613632, 2901444352662306816, 1450722176331153408, 725361088165576704, 362539804446949376, 145241105196122112, 18049583422636032, 45053588738670592, 22667534005174272, 11333767002587136, 5666883501293568, 2833441750646784, 1416171111120896, 567348067172352, 70506185244672, 175990581010432, 88545054707712, 44272527353856, 22136263676928, 11068131838464, 5531918402816, 2216203387392, 275414786112, 687463207072, 345879119952, 172939559976, 86469779988, 43234889994, 21609056261, 8657044482, 1075839008, 2685403152, 1351090312, 675545156, 337772578, 168886289, 84410376, 33816580, 4202496, 10489856, 5277696, 2638848, 1319424, 659712, 329728, 132096} - - bbBishopMoves = [64]bitboard{18049651735527937, 45053622886727936, 22667548931719168, 11334324221640704, 5667164249915392, 2833579985862656, 1416240237150208, 567382630219904, 4611756524879479810, 11529391036782871041, 5764696068147249408, 2882348036221108224, 1441174018118909952, 720587009051099136, 360293502378066048, 144117404414255168, 2323857683139004420, 1197958188344280066, 9822351133174399489, 4911175566595588352, 2455587783297826816, 1227793891648880768, 577868148797087808, 288793334762704928, 1161999073681608712, 581140276476643332, 326598935265674242, 9386671504487645697, 4693335752243822976, 2310639079102947392, 1155178802063085600, 577588851267340304, 580999811184992272, 290500455356698632, 145390965166737412, 108724279602332802, 9241705379636978241, 4620711952330133792, 2310355426409252880, 1155177711057110024, 290499906664153120, 145249955479592976, 72625527495610504, 424704217196612, 36100411639206946, 9241421692918565393, 4620710844311799048, 2310355422147510788, 145249953336262720, 72624976676520096, 283693466779728, 1659000848424, 141017232965652, 36099303487963146, 9241421688590368773, 4620710844295151618, 72624976668147712, 283691315142656, 1108177604608, 6480472064, 550848566272, 141012904249856, 36099303471056128, 9241421688590303744} - - bbRookMoves = [64]bitboard{9187484529235886208, 13781085504453754944, 16077885992062689312, 17226286235867156496, 17800486357769390088, 18087586418720506884, 18231136449196065282, 18302911464433844481, 9259260648297103488, 4665518383679160384, 2368647251370188832, 1220211685215703056, 645993902138460168, 358885010599838724, 215330564830528002, 143553341945872641, 9259541023762186368, 4629910699613634624, 2315095537539358752, 1157687956502220816, 578984165983651848, 289632270724367364, 144956323094725122, 72618349279904001, 9259542118978846848, 4629771607097753664, 2314886351157207072, 1157443723186933776, 578722409201797128, 289361752209228804, 144681423712944642, 72341259464802561, 9259542123257036928, 4629771063767613504, 2314885534022901792, 1157442769150545936, 578721386714368008, 289360695496279044, 144680349887234562, 72340177082712321, 9259542123273748608, 4629771061645230144, 2314885530830970912, 1157442765423841296, 578721382720276488, 289360691368494084, 144680345692602882, 72340172854657281, 9259542123273813888, 4629771061636939584, 2314885530818502432, 1157442765409283856, 578721382704674568, 289360691352369924, 144680345676217602, 72340172838141441, 9259542123273814143, 4629771061636907199, 2314885530818453727, 1157442765409226991, 578721382704613623, 289360691352306939, 144680345676153597, 72340172838076926} - - bbQueenMoves = [64]bitboard{9205534180971414145, 13826139127340482880, 16100553540994408480, 17237620560088797200, 17806153522019305480, 18090419998706369540, 18232552689433215490, 18303478847064064385, 13871017173176583298, 16194909420462031425, 8133343319517438240, 4102559721436811280, 2087167920257370120, 1079472019650937860, 575624067208594050, 287670746360127809, 11583398706901190788, 5827868887957914690, 12137446670713758241, 6068863523097809168, 3034571949281478664, 1517426162373248132, 722824471891812930, 361411684042608929, 10421541192660455560, 5210911883574396996, 2641485286422881314, 10544115227674579473, 5272058161445620104, 2600000831312176196, 1299860225776030242, 649930110732142865, 9840541934442029200, 4920271519124312136, 2460276499189639204, 1266167048752878738, 9820426766351346249, 4910072647826412836, 2455035776296487442, 1227517888139822345, 9550042029937901728, 4775021017124823120, 2387511058326581416, 1157867469641037908, 614821794359483434, 9530782384287059477, 4765391190004401930, 2382695595002168069, 9404792076610076608, 4702396038313459680, 2315169224285282160, 1157444424410132280, 578862399937640220, 325459994840333070, 9386102034266586375, 4693051017133293059, 9332167099941961855, 4630054752952049855, 2314886638996058335, 1157442771889699055, 578721933553179895, 289501704256556795, 180779649147209725, 9313761861428380670} - - bbKingMoves = [64]bitboard{4665729213955833856, 11592265440851656704, 5796132720425828352, 2898066360212914176, 1449033180106457088, 724516590053228544, 362258295026614272, 144959613005987840, 13853283560024178688, 16186183351374184448, 8093091675687092224, 4046545837843546112, 2023272918921773056, 1011636459460886528, 505818229730443264, 216739030602088448, 54114388906344448, 63227278716305408, 31613639358152704, 15806819679076352, 7903409839538176, 3951704919769088, 1975852459884544, 846636838289408, 211384331665408, 246981557485568, 123490778742784, 61745389371392, 30872694685696, 15436347342848, 7718173671424, 3307175149568, 825720045568, 964771708928, 482385854464, 241192927232, 120596463616, 60298231808, 30149115904, 12918652928, 3225468928, 3768639488, 1884319744, 942159872, 471079936, 235539968, 117769984, 50463488, 12599488, 14721248, 7360624, 3680312, 1840156, 920078, 460039, 197123, 49216, 57504, 28752, 14376, 7188, 3594, 1797, 770} - - bbSquares = [64]bitboard{} -) - -// init populates the bbSquares lookup table. This is done at package -// initialization because the values are constants derived from square indices. -// -//nolint:gochecknoinits // Required for lookup table initialization. -func init() { - const numOfSquaresInBoard = 64 - for sq := range numOfSquaresInBoard { - bbSquares[sq] = bitboard(uint64(1) << (uint8(63) - uint8(sq))) - } -} diff --git a/engine_test.go b/engine_test.go deleted file mode 100644 index 2709fb60..00000000 --- a/engine_test.go +++ /dev/null @@ -1,426 +0,0 @@ -package chess - -import ( - "testing" -) - -// Common test positions -var ( - // Starting position - startingPos = mustPosition("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1") - - // Middle game position with lots of possible moves - middlePos = mustPosition("r1bqk2r/pppp1ppp/2n2n2/2b1p3/2B1P3/2N2N2/PPPP1PPP/R1BQK2R w KQkq - 0 1") - - // Endgame position with few pieces - endPos = mustPosition("4k3/8/8/8/8/8/4P3/4K3 w - - 0 1") - - // Position with multiple possible pawn promotions - promoPos = mustPosition("4k3/PPPP4/8/8/8/8/4pppp/4K3 w - - 0 1") -) - -func BenchmarkStandardMoves(b *testing.B) { - benchmarks := []struct { - name string - pos *Position - wantFirst bool - }{ - {"StartingPos_AllMoves", startingPos, false}, - {"StartingPos_FirstMove", startingPos, true}, - {"MiddleGame_AllMoves", middlePos, false}, - {"MiddleGame_FirstMove", middlePos, true}, - {"Endgame_AllMoves", endPos, false}, - {"Endgame_FirstMove", endPos, true}, - {"Promotions_AllMoves", promoPos, false}, - {"Promotions_FirstMove", promoPos, true}, - } - - for _, bm := range benchmarks { - b.Run(bm.name, func(b *testing.B) { - // Reset timer to exclude setup - b.ResetTimer() - - // Enable allocation tracking - b.ReportAllocs() - - for i := 0; i < b.N; i++ { - moves := standardMoves(bm.pos, bm.wantFirst, false) - // Prevent compiler optimization - if len(moves) == 0 { - b.Fatal("unexpected zero moves") - } - } - }) - } -} - -// Benchmark specific scenarios -func BenchmarkStandardMoves_PawnPromotions(b *testing.B) { - pos := promoPos - b.ResetTimer() - b.ReportAllocs() - - for i := 0; i < b.N; i++ { - moves := standardMoves(pos, false, false) - if len(moves) == 0 { - b.Fatal("unexpected zero moves") - } - } -} - -// Benchmark with different board sizes to understand allocation scaling -func BenchmarkStandardMoves_BoardDensity(b *testing.B) { - positions := []struct { - name string - fen string - }{ - {"Empty", "4k3/8/8/8/8/8/8/4K3 w - - 0 1"}, - {"QuarterFull", "rnbqk3/pppp4/8/8/8/8/8/4K3 w - - 0 1"}, - {"HalfFull", "rnbqkbnr/pppp4/8/8/8/8/8/4K3 w - - 0 1"}, - {"Full", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"}, - } - - for _, p := range positions { - pos := mustPosition(p.fen) - b.Run(p.name, func(b *testing.B) { - b.ReportAllocs() - for i := 0; i < b.N; i++ { - moves := standardMoves(pos, false, false) - if len(moves) == 0 && p.name != "Empty" { - b.Fatal("unexpected zero moves") - } - } - }) - } -} - -func TestMoveTags(t *testing.T) { - tests := []struct { - name string - move Move - want MoveTag - fen string - }{ - { - name: "move with queen side castle", - move: Move{s1: E8, s2: C8}, - want: QueenSideCastle, - fen: "r3kb1r/p2nqppp/5n2/1B2p1B1/4P3/1Q6/PPP2PPP/R3K2R b KQkq - 1 12", - }, - { - name: "move with king side castle", - move: Move{s1: E1, s2: G1}, - want: KingSideCastle | Check, - fen: "r4b1r/ppp3pp/8/4p3/2Pq4/3P4/PP2QPPP/2k1K2R w K - 0 18", - }, - { - name: "move with king side castle and check", - move: Move{s1: E1, s2: G1}, - want: KingSideCastle | Check, - fen: "r4b1r/ppp3pp/8/4p3/2Pq4/3P1Q2/PP3PPP/1k2K2R w K - 2 19", - }, - { - name: "move with check", - move: Move{s1: D7, s2: A4}, - want: Check, - fen: "rn2k1r1/ppqb4/4p1n1/3pPp1Q/8/P1PP4/4NPPP/R1BK1B1R b q - 0 14", - }, - { - name: "move leaves king in check", - move: Move{s1: G6, s2: F8}, - want: inCheck, - fen: "r3k1r1/ppq5/2n1p1n1/3p1pBQ/b2P3P/P1P5/4NPP1/R3KB1R b q - 0 18", - }, - { - name: "capture move", - move: Move{s1: G2, s2: G3}, - want: Capture, - fen: "8/7p/3k2p1/8/2p2P2/R5bP/6K1/4r3 w - - 0 44", - }, - { - name: "normal move without tags", - move: Move{s1: D6, s2: D5}, - want: 0, - fen: "8/7p/3k2p1/8/2p2P2/R5KP/8/4r3 b - - 0 44", - }, - { - name: "en passant move", - move: Move{s1: E4, s2: F3}, - want: EnPassant | Check, - fen: "r3k2r/pbppqpb1/1pn3p1/7p/1N2pPn1/1PP4N/PB1P2PP/2QRKR2 b kq f3 0 1", - }, - { - name: "normal move without tags", - move: Move{s1: B7, s2: A6}, - want: 0, - fen: "r3k2r/pbppqpb1/1pn3p1/7p/1N2pPn1/1PP4N/PB1P2PP/2QRKR2 b kq f3 0 1", - }, - { - name: "en passant move with check", - move: Move{s1: E4, s2: F3}, - want: EnPassant | Check, - fen: "r3k1r1/pbppqpb1/1pn3p1/7p/1N2pPn1/1PP4N/PB1P2PP/2QRK1R1 b q f3 0 2", - }, - } - - for _, test := range tests { - t.Run(test.name, func(t *testing.T) { - test.move.tags = moveTags(test.move, mustPosition(test.fen)) - - if test.move.tags != test.want { - t.Errorf("fen: %s | move: %s\ntags(%d) == expected_tags(%d)", test.fen, test.move.String(), test.move.tags, test.want) - } - }) - } -} - -func TestUnsafeMoves_StartingPosition(t *testing.T) { - pos := mustPosition("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1") - moves := engine{}.UnsafeMoves(pos) - if len(moves) != 0 { - t.Errorf("expected 0 unsafe moves in starting position, got %d", len(moves)) - } -} - -func TestPromotionCheckTagIsolation(t *testing.T) { - // FEN from issue #112: k7/4P3/8/8/8/8/8/K7 w - - 0 1 - // White pawn on E7 can promote to E8. Only Queen and Rook give check - // to the black king on A8. Bishop and Knight should NOT have Check. - pos := mustPosition("k7/4P3/8/8/8/8/8/K7 w - - 0 1") - moves := pos.ValidMoves() - - // Verify total move count (3 king moves + 4 promotions = 7) - if len(moves) != 7 { - t.Fatalf("expected 7 moves, got %d", len(moves)) - } - - // Helper: find move by s1, s2, promo fields (order-independent) - findMove := func(s1, s2 Square, promo PieceType) (Move, bool) { - for _, m := range moves { - if m.s1 == s1 && m.s2 == s2 && m.promo == promo { - return m, true - } - } - return Move{}, false - } - - tests := []struct { - name string - promo PieceType - wantCheck bool - }{ - {"queen promotion with check", Queen, true}, - {"rook promotion with check", Rook, true}, - {"bishop promotion without check", Bishop, false}, - {"knight promotion without check", Knight, false}, - } - - for _, test := range tests { - t.Run(test.name, func(t *testing.T) { - m, ok := findMove(E7, E8, test.promo) - if !ok { - t.Fatalf("expected to find E7-E8=%s promotion move", test.promo.String()) - } - gotCheck := m.HasTag(Check) - if gotCheck != test.wantCheck { - t.Errorf("E7-E8=%s: Check=%v, want %v", test.promo.String(), gotCheck, test.wantCheck) - } - }) - } -} - -func TestPromotionNoCheck(t *testing.T) { - // Position where no promotion gives check against an existing black king. - // Black king on A6 is not attacked by any promoted piece on E8. - pos := mustPosition("8/4P3/k7/8/8/8/8/7K w - - 0 1") - moves := pos.ValidMoves() - - for _, m := range moves { - if m.s1 == E7 && m.s2 == E8 { - if m.HasTag(Check) { - t.Errorf("E7-E8=%s should NOT have Check tag", m.promo.String()) - } - } - } -} - -func TestUnsafeMoves_PinnedKnight(t *testing.T) { - pos := mustPosition("4k3/8/8/8/1b6/2N5/8/4K3 w - - 0 1") - moves := engine{}.UnsafeMoves(pos) - if len(moves) != 8 { - t.Fatalf("expected 8 unsafe moves for pinned knight, got %d", len(moves)) - } - for _, m := range moves { - if m.s1 != C3 { - t.Errorf("expected unsafe move from C3, got %s", m.s1.String()) - } - if !m.HasTag(inCheck) { - t.Errorf("expected unsafe move to have inCheck tag: %s", m.String()) - } - } -} - -func TestUnsafeMoves_KingIntoCheck(t *testing.T) { - pos := mustPosition("8/8/8/8/8/3r4/8/4K3 w - - 0 1") - moves := engine{}.UnsafeMoves(pos) - if len(moves) != 2 { - t.Fatalf("expected 2 unsafe moves, got %d", len(moves)) - } - expected := map[string]bool{"d1": true, "d2": true} - for _, m := range moves { - if m.s1 != E1 { - t.Errorf("expected move from E1, got %s", m.s1.String()) - } - if !expected[m.s2.String()] { - t.Errorf("unexpected unsafe move to %s", m.s2.String()) - } - } -} - -func TestDiscoveredCheck(t *testing.T) { - // White rook on e1 is blocked by white knight on e4 from checking black king on e8 - // Moving Ne4-f6 reveals the check - pos := mustPosition("4k3/8/8/8/4N3/8/8/4R1K1 w - - 0 1") - moves := pos.ValidMoves() - - foundDiscoveredCheck := false - for _, m := range moves { - if m.s1 == E4 && m.HasTag(Check) { - foundDiscoveredCheck = true - break - } - } - if !foundDiscoveredCheck { - t.Error("expected at least one move from e4 with discovered check") - } -} - -func TestEnPassantDiscoveredCheck(t *testing.T) { - // White king on e1, black rook on e8, black pawn on e4 blocks the rook. - // White pawn on d2 moves to d4. Black captures e4xd3 en passant. - // After capture, pawn is on d3 (not on e-file), rook gives check. - pos := mustPosition("4r3/8/8/8/4p3/8/3P4/4K1k1 w - - 0 1") - // White plays d2-d4 - moves := pos.ValidMoves() - var d2d4 Move - found := false - for _, m := range moves { - if m.s1 == D2 && m.s2 == D4 { - d2d4 = m - found = true - break - } - } - if !found { - t.Fatal("expected d2-d4 move") - } - - // Apply the move and get the new position - pos2 := pos.Update(&d2d4) - // Black to move, en passant on d3 - moves2 := pos2.ValidMoves() - - foundEPCheck := false - for _, m := range moves2 { - if m.HasTag(EnPassant) && m.HasTag(Check) { - foundEPCheck = true - break - } - } - if !foundEPCheck { - t.Error("expected en passant move with discovered check") - } -} - -func TestDoubleCheck(t *testing.T) { - // Black king on e8 is in double check from white queen on h5 and knight on f6 - // Clear diagonal h5-e8 by removing pawn on f7: white knight on f6, queen on h5 - // The position itself should have inCheck=true, and only king moves should be legal - pos := mustPosition("rnb1kbnr/pppp2pp/5N2/6pQ/8/8/PPPPPPPP/RNB1KB1R b KQkq - 0 1") - - // Verify the position itself has the black king in check - if !pos.inCheck { - t.Error("expected black king to be in check in this position") - } - - moves := pos.ValidMoves() - // In double check, only king moves are legal - for _, m := range moves { - if m.s1 != E8 { - t.Errorf("in double check, only king moves should be legal, got %s", m.String()) - } - } -} - -func TestKingMoveEscapesCheck(t *testing.T) { - // Black king on e8 is in check from white rook on e1 - // Ke8-d8 should escape check - pos := mustPosition("4k3/8/8/8/8/8/8/4R3 b - - 0 1") - moves := pos.ValidMoves() - - findMove := func(s1, s2 Square) (Move, bool) { - for _, m := range moves { - if m.s1 == s1 && m.s2 == s2 { - return m, true - } - } - return Move{}, false - } - - m, ok := findMove(E8, D8) - if !ok { - t.Fatal("expected to find Ke8-d8 move") - } - if m.HasTag(inCheck) { - t.Error("Ke8-d8 should not leave king in check") - } -} - -func TestKingMoveWalksIntoCheck(t *testing.T) { - // White king on e1, black rook on e8 - // Ke1-e2 should be illegal (walks into check) - pos := mustPosition("4r3/8/8/8/8/8/8/4K3 w - - 0 1") - moves := engine{}.UnsafeMoves(pos) - - findMove := func(s1, s2 Square) (Move, bool) { - for _, m := range moves { - if m.s1 == s1 && m.s2 == s2 { - return m, true - } - } - return Move{}, false - } - - m, ok := findMove(E1, E2) - if !ok { - t.Fatal("expected to find Ke1-e2 unsafe move") - } - if !m.HasTag(inCheck) { - t.Error("Ke1-e2 should have inCheck tag") - } -} - -func BenchmarkMoveTags(b *testing.B) { - pos := mustPosition("r1bqk2r/pppp1ppp/2n2n2/2b1p3/2B1P3/2N2N2/PPPP1PPP/R1BQK2R w KQkq - 0 1") - moves := engine{}.CalcMoves(pos, false) - if len(moves) == 0 { - b.Fatal("expected moves") - } - - b.ReportAllocs() - b.ResetTimer() - for i := 0; i < b.N; i++ { - for _, m := range moves { - _ = moveTags(m, pos) - } - } -} -// Helper function to convert FEN to Position -func mustPosition(fen string) *Position { - fenObject, err := FEN(fen) - pos := NewGame(fenObject).Position() - if err != nil { - panic(err) - } - return pos -} diff --git a/errors.go b/errors.go index 75232178..b5d16498 100644 --- a/errors.go +++ b/errors.go @@ -25,9 +25,9 @@ func (e *PGNError) Is(target error) bool { return e.msg == t.msg } -// Custom error types for different PGN errors -// -//nolint:gochecknoglobals // this is a custom error type. +// Package-level error sentinels and constructors used throughout the PGN +// parser. These are immutable factories, not mutable global state, so the +// gochecknoglobals warning is a false positive. var ( ErrUnterminatedComment = func(pos int) error { return &PGNError{"unterminated comment", pos} } ErrUnterminatedQuote = func(pos int) error { return &PGNError{"unterminated quote", pos} } @@ -36,7 +36,22 @@ var ( ErrInvalidSquare = func(pos int) error { return &PGNError{"invalid square", pos} } ErrInvalidRank = func(pos int) error { return &PGNError{"invalid rank", pos} } - ErrNoGameFound = errors.New("no game found in PGN data") + // ErrInvalidFEN is the sentinel for any FEN parse failure. Specific + // causes are wrapped with %w so callers can errors.Is(err, ErrInvalidFEN) + // without inspecting message text. + ErrInvalidFEN = errors.New("chess: invalid FEN") + + // ErrInvalidPGN is the sentinel for any PGN parse failure, including + // empty input. Branch on this for "the PGN did not yield a Game". + ErrInvalidPGN = errors.New("chess: invalid PGN") + + // ErrNoGameFound is returned when the PGN input contains no game. It + // wraps ErrInvalidPGN so errors.Is(err, ErrInvalidPGN) also matches. + ErrNoGameFound = fmt.Errorf("%w: no game found in PGN data", ErrInvalidPGN) + + // ErrGameAlreadyEnded is returned when a move is applied to a Game that + // already has a terminal Outcome. Callers must ClearOutcome first. + ErrGameAlreadyEnded = errors.New("chess: game already ended") ) type ParserError struct { @@ -47,6 +62,6 @@ type ParserError struct { } func (e *ParserError) Error() string { - return fmt.Sprintf("Parser error at position %d: %s (Token: %v, Value: %s)", + return fmt.Sprintf("parser error at position %d: %s (Token: %v, Value: %s)", e.Position, e.Message, e.TokenType, e.TokenValue) } diff --git a/export_test.go b/export_test.go new file mode 100644 index 00000000..0dbee9ce --- /dev/null +++ b/export_test.go @@ -0,0 +1,31 @@ +package chess + +import ( + "errors" + "io" + "testing" + + "go.uber.org/goleak" +) + +func TestMain(m *testing.M) { + goleak.VerifyTestMain(m) +} + +func PGN(r io.Reader) (func(*Game), error) { + game, err := ParsePGN(r) + if errors.Is(err, io.EOF) { + return nil, ErrNoGameFound + } + if err != nil { + return nil, err + } + return func(g *Game) { + g.copy(game) + g.tree = game.tree + }, nil +} + +func NewParser(tokens []Token) *Parser { + return newParser(tokens) +} diff --git a/fen.go b/fen.go index 3ac01c66..e9fc2373 100644 --- a/fen.go +++ b/fen.go @@ -12,49 +12,144 @@ import ( // if there is a parsing error. FEN notation format: // rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1. func decodeFEN(fen string) (*Position, error) { - const minFENParts = 6 - fen = strings.TrimSpace(fen) - parts := strings.Split(fen, " ") - - if len(parts) != minFENParts { - return nil, errors.New("chess: fen invalid format") - } - b, err := fenBoard(parts[0]) + setup, err := decodeFENSetup(fen) if err != nil { return nil, err } - turn, ok := fenTurnMap[parts[1]] - if !ok { - return nil, errors.New("chess: fen invalid turn") - } - rights, err := formCastleRights(parts[2]) + pos, err := NewPosition(setup) if err != nil { - return nil, err + return nil, fmt.Errorf("%w: %w", ErrInvalidFEN, err) } - sq, err := formEnPassant(parts[3]) + return pos, nil +} + +// decodeFENUnsafe parses a FEN string and constructs a Position without +// semantic validation. It exists for internal tests and legacy callers that +// need to create positions with arbitrary or incomplete board states. +func decodeFENUnsafe(fen string) (*Position, error) { + setup, err := decodeFENSetup(fen) if err != nil { return nil, err } - halfMoveClock, err := strconv.Atoi(parts[4]) - if err != nil || halfMoveClock < 0 { - return nil, errors.New("chess: fen invalid half move clock") + pos := &Position{ + board: setup.Board, + turn: setup.Turn, + castleRights: setup.CastleRights, + enPassantSquare: setup.EnPassant, + halfMoveClock: setup.HalfMoveClock, + moveCount: setup.FullMoveNo, + variant: setup.Variant, } - moveCount, err := strconv.Atoi(parts[5]) - if err != nil || moveCount < 1 { - return nil, errors.New("chess: fen invalid move count") + pos.inCheck, pos.checkers = checkState(pos) + pos.hash = pos.computeHash() + return pos, nil +} + +// decodeFENForHash parses a FEN string and returns a Position whose Zobrist +// hash is correct but whose inCheck/checkers fields are not populated. It is +// used by HashFromFEN to avoid the attack-set scan that full position +// construction requires. +func decodeFENForHash(fen string) (*Position, error) { + setup, err := decodeFENSetup(fen) + if err != nil { + return nil, err } pos := &Position{ - board: b, - turn: turn, - castleRights: rights, - enPassantSquare: sq, - halfMoveClock: halfMoveClock, - moveCount: moveCount, + board: setup.Board, + turn: setup.Turn, + castleRights: setup.CastleRights, + enPassantSquare: setup.EnPassant, + halfMoveClock: setup.HalfMoveClock, + moveCount: setup.FullMoveNo, + variant: setup.Variant, } pos.hash = pos.computeHash() return pos, nil } +// decodeFENSetup parses a FEN string into a Setup. It performs only syntactic +// validation; semantic validation is left to NewPosition. +// +// The parser is relaxed, matching the de-facto behavior of widely deployed +// FEN producers (shakmaty, lichess, SCID, chess.com): +// +// - Fields may be separated by spaces, tabs, or underscores ('_'). +// - Missing fields (except the board) are filled with the defaults from +// `8/8/8/8/8/8/8/8 w - - 0 1`: White to move, no castling rights, no en +// passant square, halfmove clock 0, fullmove number 1. +// - A fullmove number of 0 is accepted and treated as 1. +// +// Every returned error wraps ErrInvalidFEN so callers can branch with +// errors.Is without inspecting message text. +func decodeFENSetup(fen string) (Setup, error) { + const maxFENParts = 6 + fen = strings.TrimSpace(fen) + parts := strings.FieldsFunc(fen, func(r rune) bool { + return r == ' ' || r == '\t' || r == '_' + }) + + if len(parts) < 1 || len(parts) > maxFENParts { + return Setup{}, fmt.Errorf("chess: fen expects 1-6 fields, got %d: %w", len(parts), ErrInvalidFEN) + } + b, err := fenBoard(parts[0]) + if err != nil { + return Setup{}, fmt.Errorf("chess: fen: board: %w: %w", err, ErrInvalidFEN) + } + + // Defaults for missing fields, matching shakmaty's `8/8/8/8/8/8/8/8 w - - 0 1`. + turn := White + rights := CastleRights{} + sq := NoSquare + halfMoveClock := 0 + moveCount := 1 + variant := Standard + + if len(parts) > 1 { + var ok bool + turn, ok = fenTurnMap[parts[1]] + if !ok { + return Setup{}, fmt.Errorf("chess: fen invalid turn %q: %w", parts[1], ErrInvalidFEN) + } + } + if len(parts) > 2 { + rights, variant, err = formCastleRightsWithVariant(parts[2], b) + if err != nil { + return Setup{}, fmt.Errorf("chess: fen: castle rights: %w: %w", err, ErrInvalidFEN) + } + } + if len(parts) > 3 { + sq, err = formEnPassant(parts[3]) + if err != nil { + return Setup{}, fmt.Errorf("chess: fen: en passant: %w: %w", err, ErrInvalidFEN) + } + } + if len(parts) > 4 { + halfMoveClock, err = strconv.Atoi(parts[4]) + if err != nil || halfMoveClock < 0 { + return Setup{}, fmt.Errorf("chess: fen invalid half move clock %q: %w", parts[4], ErrInvalidFEN) + } + } + if len(parts) > 5 { + moveCount, err = strconv.Atoi(parts[5]) + if err != nil || moveCount < 0 { + return Setup{}, fmt.Errorf("chess: fen invalid move count %q: %w", parts[5], ErrInvalidFEN) + } + if moveCount == 0 { + moveCount = 1 + } + } + + return Setup{ + Board: *b, + Turn: turn, + CastleRights: rights, + EnPassant: sq, + HalfMoveClock: halfMoveClock, + FullMoveNo: moveCount, + Variant: variant, + }, nil +} + const ( fileMapSize = 8 pieceMapSize = 32 @@ -66,7 +161,7 @@ var ( //note: this is a sync.Pool //nolint:gochecknoglobals // this is a pool. pieceMapPool = sync.Pool{ - New: func() interface{} { + New: func() any { return make(map[Square]Piece, pieceMapSize) }, } @@ -75,17 +170,26 @@ var ( //note: this is a sync.Pool //nolint:gochecknoglobals // this is a pool. fileMapPool = sync.Pool{ - New: func() interface{} { + New: func() any { return make(map[File]Piece, fileMapSize) }, } ) -// clearMap helper to clear a map without deallocating. -func clearMap[K comparable, V any](m map[K]V) { - for k := range m { - delete(m, k) +func getPieceMap() map[Square]Piece { + m, ok := pieceMapPool.Get().(map[Square]Piece) + if !ok || m == nil { + return make(map[Square]Piece, pieceMapSize) + } + return m +} + +func getFileMap() map[File]Piece { + m, ok := fileMapPool.Get().(map[File]Piece) + if !ok || m == nil { + return make(map[File]Piece, fileMapSize) } + return m } // fenBoard generates board from FEN format while minimizing allocations. @@ -97,12 +201,12 @@ func fenBoard(boardStr string) (*Board, error) { var rankBuffer [maxRankLen]string // Get maps from pools - m, _ := pieceMapPool.Get().(map[Square]Piece) - fileMap, _ := fileMapPool.Get().(map[File]Piece) + m := getPieceMap() + fileMap := getFileMap() // Clear maps (in case they were reused) - clearMap(m) - clearMap(fileMap) + clear(m) + clear(fileMap) // Ensure maps are returned to pools on exit defer func() { @@ -141,11 +245,11 @@ func fenBoard(boardStr string) (*Board, error) { rank := Rank(7 - i) // Clear fileMap for reuse - clearMap(fileMap) + clear(fileMap) // Parse rank into reused map if err := fenFormRank(rankBuffer[i], fileMap); err != nil { - return nil, err + return nil, fmt.Errorf("chess: fen: rank %d: %w", 8-i, err) } // Transfer pieces to main map @@ -158,7 +262,7 @@ func fenBoard(boardStr string) (*Board, error) { // Note: NewBoard must copy the map since we're returning m to the pool board, err := NewBoard(m) if err != nil { - return nil, err + return nil, fmt.Errorf("chess: fen: board construction: %w", err) } return board, nil } @@ -195,29 +299,235 @@ func fenFormRank(rankStr string, m map[File]Piece) error { } func formCastleRights(castleStr string) (CastleRights, error) { - // check for duplicates aka. KKkq right now is valid - for _, s := range []string{"K", "Q", "k", "q", "-"} { - if strings.Count(castleStr, s) > 1 { - return "-", fmt.Errorf("chess: fen invalid castle rights %s", castleStr) - } + if castleStr == "-" { + return CastleRights{}, nil } - for _, r := range castleStr { - c := fmt.Sprintf("%c", r) + var seen [256]bool + var cr CastleRights + for i := range castleStr { + c := castleStr[i] switch c { - case "K", "Q", "k", "q", "-": + case 'K': + if seen[c] { + return CastleRights{}, fmt.Errorf("chess: fen invalid castle rights %s", castleStr) + } + seen[c] = true + cr.White.KingSide = true + case 'Q': + if seen[c] { + return CastleRights{}, fmt.Errorf("chess: fen invalid castle rights %s", castleStr) + } + seen[c] = true + cr.White.QueenSide = true + case 'k': + if seen[c] { + return CastleRights{}, fmt.Errorf("chess: fen invalid castle rights %s", castleStr) + } + seen[c] = true + cr.Black.KingSide = true + case 'q': + if seen[c] { + return CastleRights{}, fmt.Errorf("chess: fen invalid castle rights %s", castleStr) + } + seen[c] = true + cr.Black.QueenSide = true default: - return "-", fmt.Errorf("chess: fen invalid castle rights %s", castleStr) + return CastleRights{}, fmt.Errorf("chess: fen invalid castle rights %s", castleStr) + } + } + return cr, nil +} + +// formCastleRightsWithVariant parses a FEN castling-rights field with +// Chess960 awareness. It accepts the standard KQkq letters, Shredder-FEN and +// X-FEN file letters (uppercase A-H = white rook files, lowercase a-h = black +// rook files), and any X-FEN mix of the two. File letters are mapped to king +// or queen side using each color's king file on its back rank. The presence of +// any file letter implies the Chess960 variant; a pure KQkq (or "-") field is +// Standard. The board is required to resolve file letters. +func formCastleRightsWithVariant(castleStr string, board *Board) (CastleRights, Variant, error) { + if castleStr == "-" { + return CastleRights{}, Standard, nil + } + if len(castleStr) > 8 { + return CastleRights{}, Standard, fmt.Errorf("chess: fen invalid castle rights %s", castleStr) + } + var ( + cr CastleRights + variant = Standard + seen = [256]bool{} + whiteKingFile = backRankKingFile(board, White) + blackKingFile = backRankKingFile(board, Black) + ) + for i := range castleStr { + c := castleStr[i] + if seen[c] { + return CastleRights{}, Standard, fmt.Errorf("chess: fen invalid castle rights %s", castleStr) + } + seen[c] = true + switch { + case c == 'K': + cr.White.KingSide = true + case c == 'Q': + cr.White.QueenSide = true + case c == 'k': + cr.Black.KingSide = true + case c == 'q': + cr.Black.QueenSide = true + case c >= 'A' && c <= 'H': + variant = Chess960 + if err := setRookRight(&cr, board, White, int(c-'A'), whiteKingFile, castleStr); err != nil { + return CastleRights{}, Standard, err + } + case c >= 'a' && c <= 'h': + variant = Chess960 + if err := setRookRight(&cr, board, Black, int(c-'a'), blackKingFile, castleStr); err != nil { + return CastleRights{}, Standard, err + } + default: + return CastleRights{}, Standard, fmt.Errorf("chess: fen invalid castle rights %s", castleStr) + } + } + return cr, variant, nil +} + +// backRankKingFile returns the file (0-7) of the given color's king on its back +// rank, or -1 if it is not there. Chess960 castling rights name rooks by file, +// so the king's file is needed to decide king side versus queen side. +func backRankKingFile(board *Board, c Color) int { + var rank Rank + var king Piece + if c == White { + rank, king = Rank1, WhiteKing + } else { + rank, king = Rank8, BlackKing + } + for f := range 8 { + if board.Piece(NewSquare(File(f), rank)) == king { + return f + } + } + return -1 +} + +// setRookRight maps a Chess960 rook file to the king or queen side based on its +// position relative to the king's file: a rook to the king's right (higher +// file) grants the king side; to the left (lower file) grants the queen side. +// The Shredder letter names a specific rook file, so a friendly rook must +// actually occupy that file on the back rank; a malformed FEN whose rights +// claim a file with no rook is rejected here (the alternative — silently +// dropping the right — would corrupt the position's round-trip). +func setRookRight(cr *CastleRights, board *Board, c Color, rookFile, kingFile int, src string) error { + if kingFile < 0 { + return fmt.Errorf("chess: fen castle rights %s: %s king not on back rank", src, c.Name()) + } + if rookFile == kingFile { + return fmt.Errorf("chess: fen castle rights %s: rook on king's file", src) + } + var ( + rank Rank + rook Piece + ) + if c == White { + rank, rook = Rank1, WhiteRook + } else { + rank, rook = Rank8, BlackRook + } + if board.Piece(NewSquare(File(rookFile), rank)) != rook { + return fmt.Errorf("chess: fen castle rights %s: no %s rook on file %d", src, c.Name(), rookFile) + } + if rookFile > kingFile { + if c == White { + cr.White.KingSide = true + } else { + cr.Black.KingSide = true + } + } else { + if c == White { + cr.White.QueenSide = true + } else { + cr.Black.QueenSide = true + } + } + return nil +} + +// appendCastleRights appends the FEN castling-rights field to buf. Standard +// positions emit the KQkq form; Chess960 positions emit Shredder-FEN file +// letters (uppercase for white rooks, lowercase for black), one per held +// right, in the canonical KQkq positional order, or "-" when no side can +// castle. The board is required to locate each Chess960 rook's file. +func appendCastleRights(buf []byte, cr CastleRights, board *Board, variant Variant) []byte { + if variant == Standard { + return append(buf, cr.String()...) + } + start := len(buf) + whiteKing := backRankKingFile(board, White) + blackKing := backRankKingFile(board, Black) + if cr.CanCastle(White, KingSide) { + if f := rookFileForSide(board, White, whiteKing, KingSide); f >= 0 { + buf = append(buf, byte('A'+f)) + } + } + if cr.CanCastle(White, QueenSide) { + if f := rookFileForSide(board, White, whiteKing, QueenSide); f >= 0 { + buf = append(buf, byte('A'+f)) + } + } + if cr.CanCastle(Black, KingSide) { + if f := rookFileForSide(board, Black, blackKing, KingSide); f >= 0 { + buf = append(buf, byte('a'+f)) + } + } + if cr.CanCastle(Black, QueenSide) { + if f := rookFileForSide(board, Black, blackKing, QueenSide); f >= 0 { + buf = append(buf, byte('a'+f)) + } + } + if len(buf) == start { + buf = append(buf, '-') + } + return buf +} + +// rookFileForSide returns the file (0-7) of the rook that grants the given +// castling side for color c: the nearest friendly rook on the back rank to the +// king's right for KingSide, or to the king's left for QueenSide, or -1 if the +// king is not on its back rank or no such rook exists. +func rookFileForSide(board *Board, c Color, kingFile int, side Side) int { + if kingFile < 0 { + return -1 + } + var rank Rank + var rook Piece + if c == White { + rank, rook = Rank1, WhiteRook + } else { + rank, rook = Rank8, BlackRook + } + switch side { + case KingSide: + for f := kingFile + 1; f < 8; f++ { + if board.Piece(NewSquare(File(f), rank)) == rook { + return f + } + } + case QueenSide: + for f := kingFile - 1; f >= 0; f-- { + if board.Piece(NewSquare(File(f), rank)) == rook { + return f + } } } - return CastleRights(castleStr), nil + return -1 } func formEnPassant(enPassant string) (Square, error) { if enPassant == "-" { return NoSquare, nil } - sq := SquareFromString(enPassant) - if sq == NoSquare || !(sq.Rank() == Rank3 || sq.Rank() == Rank6) { + sq, err := ParseSquare(enPassant) + if err != nil || (sq.Rank() != Rank3 && sq.Rank() != Rank6) { return NoSquare, fmt.Errorf("chess: fen invalid En Passant square %s", enPassant) } return sq, nil diff --git a/fen_test.go b/fen_test.go index ed5bab0f..4958eb44 100644 --- a/fen_test.go +++ b/fen_test.go @@ -1,6 +1,7 @@ package chess import ( + "errors" "testing" ) @@ -54,7 +55,6 @@ var ( "rnbqkbnr/pp1ppppp/8/2p5/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq c12 1 2", "7k/8/8/8/8/8/8/R6K w - - 0 -1", "7k/8/8/8/8/8/8/2B1KB2 w - - -1 1", - "8/8/8/4k3/8/8/8/R3K2R w KQ - 0 0", "8/8/8/8/4k3/8/3KP3/8 c - - 0 1", "8/8/5k2/8/5K2/8/4P3P/8 w - - 0 1", "r4rk1/1b2bppp/ppq1p3/2pp3n/5P2/1P1BP3/PBPPQ1PP/R4RK1 w e4 - 0 1", @@ -78,6 +78,45 @@ func TestValidFENs(t *testing.T) { } } +func TestRelaxedFENParsing(t *testing.T) { + tests := []struct { + name string + fen string + // wantFEN is the canonical re-rendered FEN after parsing. + wantFEN string + }{ + {"board only", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w - - 0 1"}, + {"board and turn", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR b", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR b - - 0 1"}, + {"underscore separators", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR_w_KQkq_-_0_1", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"}, + {"multiple spaces", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"}, + {"zero fullmove becomes one", "8/8/8/4k3/8/8/8/R3K2R w KQ - 0 0", "8/8/8/4k3/8/8/8/R3K2R w KQ - 0 1"}, + {"tab separator", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR\tw\tKQkq\t-\t0\t1", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + pos, err := decodeFEN(tt.fen) + if err != nil { + t.Fatalf("decodeFEN(%q) error = %v; relaxed parser should accept it", tt.fen, err) + } + if got := pos.String(); got != tt.wantFEN { + t.Errorf("decodeFEN(%q).String() = %q, want %q", tt.fen, got, tt.wantFEN) + } + }) + } +} + +func TestFENErrorWrapsSentinel(t *testing.T) { + for _, fen := range []string{"", "garbage", "8/8/8/8/8/8/8/8 x - 0 1", "8/8/8/8/8/8/8/8 w KQkq - 0 -1", "8/8/8/8/8/8/8/8 w - - 0 1"} { + _, err := decodeFEN(fen) + if err == nil { + t.Fatalf("decodeFEN(%q) expected error", fen) + } + if !errors.Is(err, ErrInvalidFEN) { + t.Errorf("decodeFEN(%q) error = %v, want errors.Is(err, ErrInvalidFEN)", fen, err) + } + } +} + func TestInvalidFENs(t *testing.T) { for _, f := range invalidFENs { if _, err := decodeFEN(f); err == nil { @@ -86,6 +125,22 @@ func TestInvalidFENs(t *testing.T) { } } +func TestFenBoardHandlesInvalidPooledMaps(t *testing.T) { + pieceMapPool.Put("not a piece map") + fileMapPool.Put("not a file map") + + board, err := fenBoard("8/8/8/8/8/8/8/R6K") + if err != nil { + t.Fatalf("fenBoard returned error: %v", err) + } + if got := board.Piece(A1); got != WhiteRook { + t.Fatalf("A1 = %v, want %v", got, WhiteRook) + } + if got := board.Piece(H1); got != WhiteKing { + t.Fatalf("H1 = %v, want %v", got, WhiteKing) + } +} + func BenchmarkFenBoard(b *testing.B) { // Test cases representing different scenarios benchmarks := []struct { @@ -120,7 +175,7 @@ func BenchmarkFenBoard(b *testing.B) { b.ResetTimer() b.ReportAllocs() // Run the benchmark - for i := 0; i < b.N; i++ { + for range b.N { board, err := fenBoard(bm.fen) if err != nil { b.Fatal(err) diff --git a/framer.go b/framer.go new file mode 100644 index 00000000..b6417578 --- /dev/null +++ b/framer.go @@ -0,0 +1,277 @@ +// PGN game framing: splits a byte stream into individual PGN game records. +// +// The pgnFramer type reads from an io.Reader, buffers data, and uses +// splitPGNGames to emit complete PGN records as strings. The splitPGNGames +// function and its helpers handle PGN-specific syntax including game metadata, +// moves, comments, and variations. Token-level parsing is driven lazily from +// pgn.go via lexerTokenSource; this file does not own any token-shaped public +// API. + +package chess + +import ( + "bufio" + "bytes" + "io" +) + +// Split function for bufio.Scanner to split PGN games. +func splitPGNGames(data []byte, atEOF bool) (int, []byte, error) { + // Skip leading whitespace + start := skipLeadingWhitespace(data) + if start == len(data) { + return handleEOF(data, atEOF) + } + + // Find the start of the game + start = findGameStart(data, start, atEOF) + if start == -1 { + return 0, nil, nil + } + + // Process the game content + return processGameContent(data, start, atEOF) +} + +// Helper to skip leading whitespace. +func skipLeadingWhitespace(data []byte) int { + start := 0 + for ; start < len(data); start++ { + if !isWhitespace(data[start]) { + break + } + } + return start +} + +// Helper to handle EOF scenarios. +func handleEOF(data []byte, atEOF bool) (int, []byte, error) { + if atEOF { + return len(data), nil, nil + } + return 0, nil, nil +} + +// Helper to find the start of a game (normally first '[' character). +func findGameStart(data []byte, start int, atEOF bool) int { + // If the first character is not '[', find the next '[' character + if start < len(data) && data[start] != '[' { + idx := bytes.IndexByte(data[start:], '[') + if idx == -1 { + return findTaglessGameStart(data, start, atEOF) + } + start += idx + } + return start +} + +// Helper to find the start of a game without tags. +func findTaglessGameStart(data []byte, start int, atEOF bool) int { + // If the first character is not '[', find the next '[' character + if start < len(data) && data[start] != '1' { + idx := bytes.IndexByte(data[start:], '1') + if idx == -1 || data[start+idx+1] != '.' || + (idx != 0 && data[start+idx-1] != '\n') { + if atEOF { + return -1 // this could be removed as we return -1 in the next line anyway (just to be explicit and debuggable) + } + return -1 + } + start += idx + } + + return start +} + +// Helper to process the content of a game and return the token or advance position. +func processGameContent(data []byte, start int, atEOF bool) (int, []byte, error) { + var i int // Loop variable + var inBrackets, inComment, foundResult bool // State variables + resultStart := -1 // Start position of result token + + // Process the game content + for i = start; i < len(data); i++ { + // first check if we are in brackets or comments + inBrackets = updateBracketState(data[i], inBrackets, inComment) + inComment = updateCommentState(data[i], inComment) + + // when we are not in brackets or comments, we can check for the result token + if foundResult && !inBrackets && !inComment && data[i] == '\n' { + nextGame := findNextGameStart(data[i:]) + if nextGame != -1 { + // return the next game start position and the current game content + return i + nextGame, bytes.TrimSpace(data[start:i]), nil + } + } + + // check for result token if we are not in brackets or comments and haven't found it yet + if !inBrackets && !inComment && !foundResult { + foundResult, resultStart = checkForResult(data, i) + } + } + + // check for result token at EOF if we haven't found it yet + if atEOF && foundResult && resultStart > 0 { + return len(data), bytes.TrimSpace(data[start:]), nil + } + + if !atEOF || i <= start { + return 0, nil, nil + } + + // return the current game content + return len(data), bytes.TrimSpace(data[start:]), nil +} + +// Helper to update bracket state based on current character. +func updateBracketState(ch byte, inBrackets bool, inComment bool) bool { + if ch == '[' && !inComment { + return true + } else if ch == ']' && !inComment { + return false + } + return inBrackets +} + +// Helper to update comment state based on current character. +func updateCommentState(ch byte, inComment bool) bool { + if ch == '{' { + return true + } else if ch == '}' && inComment { + return false + } + return inComment +} + +// Helper to find the next game start after a newline character. +func findNextGameStart(data []byte) int { + nextGame := bytes.Index(data, []byte("[Event ")) + if nextGame != -1 { + return nextGame + } + return -1 +} + +// Helper to check for game result tokens (e.g., "1-0", "0-1", "1/2-1/2", "*"). +func checkForResult(data []byte, i int) (bool, int) { + const minLength = 3 // Minimum length for results like "1-0" + const fullResultLength = 7 // Length for "1/2-1/2" + + switch data[i] { + case '1', '0', '*': + default: + return false, -1 + } + + if len(data)-i >= minLength { + switch { + case bytes.HasPrefix(data[i:], []byte("1-0")): + return true, i + case bytes.HasPrefix(data[i:], []byte("0-1")): + return true, i + case len(data)-i >= fullResultLength && bytes.HasPrefix(data[i:], []byte("1/2-1/2")): + return true, i + case data[i] == '*': + return true, i + default: + break + } + } + return false, -1 +} + +type pgnFramer struct { + reader *bufio.Reader + buffer []byte + chunk []byte + baseOffset int64 + index int64 + readErr error + eof bool +} + +func newPGNFramer(r io.Reader, opts ...PGNOption) *pgnFramer { + options := applyPGNOptions(opts) + bufferSize := options.bufferSize + if bufferSize <= 0 { + bufferSize = 256 * 1024 + } + return &pgnFramer{reader: bufio.NewReaderSize(r, bufferSize), chunk: make([]byte, bufferSize)} +} + +func (f *pgnFramer) next() (PGNRecord, error) { + for { + if f.readErr != nil && len(f.buffer) == 0 { + err := f.readErr + f.readErr = nil + return PGNRecord{}, err + } + + advance, token, err := splitPGNGames(f.buffer, f.eof) + if err != nil { + return PGNRecord{}, err + } + if advance == 0 && token == nil { + if f.eof { + return PGNRecord{}, io.EOF + } + if readErr := f.readMore(); readErr != nil && len(f.buffer) == 0 { + return PGNRecord{}, readErr + } + continue + } + start := f.baseOffset + if len(token) > 0 { + if rel := bytes.Index(f.buffer[:advance], token); rel >= 0 { + start = f.baseOffset + int64(rel) + } + } + f.advance(advance) + f.baseOffset += int64(advance) + if len(token) == 0 { + continue + } + f.index++ + return PGNRecord{Index: f.index, Offset: start, Raw: string(token)}, nil + } +} + +func (f *pgnFramer) readMore() error { + n, err := f.reader.Read(f.chunk) + if n > 0 { + f.buffer = append(f.buffer, f.chunk[:n]...) + } + if err == io.EOF { + f.eof = true + return nil + } + if err != nil { + f.readErr = err + } + return err +} + +func (f *pgnFramer) advance(n int) { + if n >= len(f.buffer) { + f.buffer = f.buffer[:0] + return + } + retained := len(f.buffer) - n + if retained*4 < cap(f.buffer) { + f.buffer = append([]byte(nil), f.buffer[n:]...) + return + } + f.buffer = f.buffer[n:] +} + +func applyPGNOptions(opts []PGNOption) pgnOptions { + options := defaultPGNOptions() + for _, opt := range opts { + opt(&options) + } + return options +} + +func defaultPGNOptions() pgnOptions { + return pgnOptions{moveTextCodec: PGNImportSAN()} +} diff --git a/game.go b/game.go index 947e0475..033fe55c 100644 --- a/game.go +++ b/game.go @@ -1,24 +1,3 @@ -/* -Package chess provides a complete chess game implementation with support for move -validation, game tree management, and standard chess formats (PGN, FEN). -The package manages complete chess games including move history, variations, -and game outcomes. It supports standard chess rules including all special moves -(castling, en passant, promotion) and automatic draw detection. -Example usage: - - // Create new game - game := NewGame() - - // Make moves - game.PushMove("e4", nil) - game.PushMove("e5", nil) - - // Check game status - - if game.Outcome() != NoOutcome { - fmt.Printf("Game ended: %s by %s\n", game.Outcome(), game.Method()) - } -*/ package chess import ( @@ -26,59 +5,7 @@ import ( "errors" "fmt" "io" - "slices" - "strings" -) - -// A Outcome is the result of a game. -type Outcome string - -const ( - UnknownOutcome Outcome = "" - // NoOutcome indicates that a game is in progress or ended without a result. - NoOutcome Outcome = "*" - // WhiteWon indicates that white won the game. - WhiteWon Outcome = "1-0" - // BlackWon indicates that black won the game. - BlackWon Outcome = "0-1" - // Draw indicates that game was a draw. - Draw Outcome = "1/2-1/2" -) - -// String implements the fmt.Stringer interface. -func (o Outcome) String() string { - return string(o) -} - -// A Method is the method that generated the outcome. -type Method uint8 - -const ( - // NoMethod indicates that an outcome hasn't occurred or that the method can't be determined. - NoMethod Method = iota - // Checkmate indicates that the game was won checkmate. - Checkmate - // Resignation indicates that the game was won by resignation. - Resignation - // DrawOffer indicates that the game was drawn by a draw offer. - DrawOffer - // Stalemate indicates that the game was drawn by stalemate. - Stalemate - // ThreefoldRepetition indicates that the game was drawn when the game - // state was repeated three times and a player requested a draw. - ThreefoldRepetition - // FivefoldRepetition indicates that the game was automatically drawn - // by the game state being repeated five times. - FivefoldRepetition - // FiftyMoveRule indicates that the game was drawn by the half - // move clock being one hundred or greater when a player requested a draw. - FiftyMoveRule - // SeventyFiveMoveRule indicates that the game was automatically drawn - // when the half move clock was one hundred and fifty or greater. - SeventyFiveMoveRule - // InsufficientMaterial indicates that the game was automatically drawn - // because there was insufficient material for checkmate. - InsufficientMaterial + "maps" ) // TagPairs represents a collection of PGN tag pairs. @@ -86,50 +13,13 @@ type TagPairs map[string]string // A Game represents a single chess game. type Game struct { - pos *Position // Current position - outcome Outcome // Game result - tagPairs TagPairs // PGN tag pairs - rootMove *Move // Root of move tree - currentMove *Move // Current position in tree - comments [][]string // Game comments - method Method // How the game ended - ignoreFivefoldRepetitionDraw bool // Flag for automatic FivefoldRepetition draw handling - ignoreSeventyFiveMoveRuleDraw bool // Flag for automatic SeventyFiveMoveRule draw handling - ignoreInsufficientMaterialDraw bool // Flag for automatic InsufficientMaterial draw handling -} - -// PGN takes a reader and returns a function that updates -// the game to reflect the PGN data. The PGN can use any -// move notation supported by this package. The returned -// function is designed to be used in the NewGame constructor. -// An error is returned if there is a problem parsing the PGN data. -func PGN(r io.Reader) (func(*Game), error) { - scanner := NewScanner(r) - - if !scanner.HasNext() { - return nil, ErrNoGameFound - } - - gameScanned, err := scanner.ScanGame() - if err != nil { - return nil, err - } - - tokens, err := TokenizeGame(gameScanned) - if err != nil { - return nil, err - } - - parser := NewParser(tokens) - game, err := parser.Parse() - if err != nil { - return nil, err - } - - // Return a function that updates the game with the parsed game state - return func(g *Game) { - g.copy(game) - }, nil + outcome Outcome // Game result + tagPairs TagPairs // PGN tag pairs + tree *MoveTree // Move tree and active cursor + method Method // How the game ended + ignoreFivefoldRepetitionDraw bool // Flag for automatic FivefoldRepetition draw handling + ignoreSeventyFiveMoveRuleDraw bool // Flag for automatic SeventyFiveMoveRule draw handling + ignoreInsufficientMaterialDraw bool // Flag for automatic InsufficientMaterial draw handling } // FEN takes a string and returns a function that updates @@ -140,15 +30,14 @@ func PGN(r io.Reader) (func(*Game), error) { func FEN(fen string) (func(*Game), error) { pos, err := decodeFEN(fen) if err != nil { - return nil, err + return nil, fmt.Errorf("chess: game FEN option: %w", err) } if pos == nil { return nil, errors.New("chess: invalid FEN") } return func(g *Game) { - pos.inCheck = isInCheck(pos) - g.pos = pos - g.rootMove.position = pos + pos.inCheck, pos.checkers = checkState(pos) + g.tree.setRootPosition(pos) g.evaluatePositionStatus() }, nil } @@ -165,17 +54,12 @@ func FEN(fen string) (func(*Game), error) { // game := NewGame(FEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1")) func NewGame(options ...func(*Game)) *Game { pos := StartingPosition() - rootMove := &Move{ - position: pos, - } game := &Game{ - rootMove: rootMove, - tagPairs: make(map[string]string), - currentMove: rootMove, - pos: pos, - outcome: NoOutcome, - method: NoMethod, + tree: newMoveTree(pos), + tagPairs: make(map[string]string), + outcome: NoOutcome, + method: NoMethod, } for _, f := range options { if f != nil { @@ -185,187 +69,105 @@ func NewGame(options ...func(*Game)) *Game { return game } -// AddVariation adds a new variation to the game. -// The parent move must be a move in the game or nil to add a variation to the root. -func (g *Game) AddVariation(parent *Move, newMove *Move) { - parent.children = append(parent.children, newMove) - newMove.parent = parent -} - -// NavigateToMainLine navigates to the main line of the game. -// The main line is the first child of each move. -func (g *Game) NavigateToMainLine() { - current := g.currentMove - - // First, navigate up to find a move that's part of the main line - for current.parent != nil && !isMainLine(current) { - current = current.parent - } - - // If there are no moves in the game, stay at root - if len(g.rootMove.children) == 0 { - g.currentMove = g.rootMove - return - } - - // Otherwise, navigate to the first move of the main line - g.currentMove = g.rootMove.children[0] -} - -func isMainLine(move *Move) bool { - if move.parent == nil { - return true - } - return move == move.parent.children[0] && isMainLine(move.parent) -} - -// GoBack navigates to the previous move in the game. -// Returns true if the move was successful. Returns false if there are no moves to go back to. -// If the game is at the start, it will return false. -func (g *Game) GoBack() bool { - if g.currentMove != nil && g.currentMove.parent != nil { - g.currentMove = g.currentMove.parent - g.pos = g.currentMove.position.copy() - return true - } - return false -} - -// GoForward navigates to the next move in the game. -// Returns true if the move was successful. Returns false if there are no moves to go forward to. -// If the game is at the end, it will return false. -func (g *Game) GoForward() bool { - // Check if current move exists and has children - if g.currentMove != nil && len(g.currentMove.children) > 0 { - g.currentMove = g.currentMove.children[0] // Follow main line - g.pos = g.currentMove.position - return true - } - return false -} +// MoveTree returns the game's move tree. +func (g *Game) MoveTree() *MoveTree { return g.tree } // IsAtStart returns true if the game is at the start. func (g *Game) IsAtStart() bool { - return g.currentMove == nil || g.currentMove == g.rootMove + return g.tree == nil || g.tree.Current() == nil || g.tree.Current() == g.tree.Root() } // IsAtEnd returns true if the game is at the end. func (g *Game) IsAtEnd() bool { - return g.currentMove != nil && len(g.currentMove.children) == 0 + return g.tree != nil && g.tree.Current() != nil && len(g.tree.Current().children) == 0 } // ValidMoves returns all legal moves in the current position. func (g *Game) ValidMoves() []Move { - return g.pos.ValidMoves() + return g.currentPosition().ValidMoves() } // UnsafeMoves returns all pseudo-legal moves that leave the moving side's king in check. // These moves are valid piece movements but illegal because they expose the king. func (g *Game) UnsafeMoves() []Move { - return g.pos.UnsafeMoves() + return g.currentPosition().UnsafeMoves() } -// Moves returns the move history of the game following the main line. -func (g *Game) Moves() []*Move { - if g.rootMove == nil { - return nil - } - - moves := make([]*Move, 0) - current := g.rootMove - - // Traverse the main line (first child of each move) - for current != nil { - moves = append(moves, current) - if len(current.children) == 0 { - break - } - // Follow main line (first variation) - current = current.children[0] +// Moves returns the main-line move values of the game. +func (g *Game) Moves() []Move { + nodes := g.tree.MainLine() + moves := make([]Move, len(nodes)) + for i, node := range nodes { + moves[i] = node.move } - - return moves[1:] // Skip the root move + return moves } -// MoveHistory is a move's result from Game's MoveHistory method. -// It contains the move itself, any comments, and the pre and post positions. -type MoveHistory struct { - PrePosition *Position - PostPosition *Position - Move *Move - Comments []string +// MoveListEntry is a single move in a [MoveList]: the move itself plus any +// comments attached to it. Positions are not cached here — callers that need +// the pre/post position replay it via [Game.MoveTree] and the cursor API. +type MoveListEntry struct { + Move Move + Comments []string } -// MoveHistory returns the main-line moves in order along with the pre and post -// positions and any comments. Variations are not included. -// Returns an empty slice for games with no moves. -func (g *Game) MoveHistory() []*MoveHistory { - if g.rootMove == nil || len(g.rootMove.children) == 0 { - return []*MoveHistory{} - } - - history := make([]*MoveHistory, 0) - current := g.rootMove +// MoveList is the main-line move sequence of a game. Variations are not +// included. The zero value is an empty list; use [Game.MoveList] to obtain one. +type MoveList []MoveListEntry - for current != nil && len(current.children) > 0 { - move := current.children[0] - if move == nil { - break - } - comments := []string(nil) - if move.Comments() != "" { - comments = []string{move.Comments()} +// MoveList returns the main-line moves in order with any comments. +// Variations are not included. The returned slice is safe to retain: it holds +// no references to the game's live cursor state. +// Returns an empty slice for games with no moves. +func (g *Game) MoveList() MoveList { + root := g.tree.Root() + if root == nil || len(root.children) == 0 { + return MoveList{} + } + + // Walk the cursor along the main line; capture the move + comments only. + defer g.tree.setCurrent(g.tree.Current()) + g.tree.Reset() + list := make(MoveList, 0, len(root.children)) + + for g.tree.GoForward() { + node := g.tree.Current() + var comments []string + if node != nil && node.Comments() != "" { + comments = []string{node.Comments()} } - - history = append(history, &MoveHistory{ - PrePosition: current.position, - PostPosition: move.position, - Move: move, - Comments: comments, + list = append(list, MoveListEntry{ + Move: node.move, + Comments: comments, }) - current = move } - return history -} - -// GetRootMove returns the root move of the game. -func (g *Game) GetRootMove() *Move { - return g.rootMove + return list } -// Variations returns all alternative moves at the given position. -func (g *Game) Variations(move *Move) []*Move { - if move == nil || len(move.children) <= 1 { +// Position returns the game's current position. +func (g *Game) Position() *Position { + pos := g.currentPosition() + if pos == nil { return nil } - // Return all moves except the main line (first child) - return move.children[1:] + return pos.copy() } -// Comments returns the comments for the game indexed by moves. -// Comments returns the comments for the game indexed by moves. -func (g *Game) Comments() [][]string { - if g.comments == nil { - return [][]string{} +// Variant returns the starting-position variant of the game (Standard or +// Chess960), derived from the game's root position. +func (g *Game) Variant() Variant { + if g == nil || g.tree == nil || g.tree.rootPos == nil { + return Standard } - return append([][]string(nil), g.comments...) -} - -// Position returns the game's current position. -func (g *Game) Position() *Position { - return g.pos + return g.tree.rootPos.variant } -// CurrentPosition returns the game's current move position. -// This is the position at the current pointer in the move tree. -// This should be used to get the current position of the game instead of Position(). -func (g *Game) CurrentPosition() *Position { - if g.currentMove == nil { - return g.pos +func (g *Game) currentPosition() *Position { + if g == nil || g.tree == nil { + return nil } - - return g.currentMove.position + return g.tree.position() } // Outcome returns the game outcome. @@ -378,286 +180,26 @@ func (g *Game) Method() Method { return g.method } -// FEN returns the FEN notation of the current position. -func (g *Game) FEN() string { - return g.pos.String() -} - -// escapeTagValue escapes backslash and double-quote characters so that the -// resulting string is safe to embed inside a PGN tag value. -func escapeTagValue(v string) string { - var sb strings.Builder - for i := 0; i < len(v); i++ { - c := v[i] - if c == '\\' || c == '"' { - sb.WriteByte('\\') - } - sb.WriteByte(c) - } - return sb.String() -} - // String implements the fmt.Stringer interface and returns -// the game's PGN. +// the game's PGN. It delegates to DefaultPGNRenderer. func (g *Game) String() string { - var sb strings.Builder - - tagPairList := make([]sortableTagPair, len(g.tagPairs)) - - var idx uint = 0 - for tag, value := range g.tagPairs { - tagPairList[idx] = sortableTagPair{ - Key: tag, - Value: value, - } - idx++ - } - - slices.SortFunc(tagPairList, cmpTags) - - // Write tag pairs. - for _, tagPair := range tagPairList { - sb.WriteString(fmt.Sprintf("[%s \"%s\"]\n", tagPair.Key, escapeTagValue(tagPair.Value))) - } - - // Append empty line after tag pairs as per definition - if len(g.tagPairs) > 0 { - sb.WriteString("\n") - } - - // Assume g.rootMove is a dummy root (holding the initial position) - // and that its first child is the first actual move. - needTrailingSpace := false - if g.rootMove != nil { - if len(g.rootMove.children) > 0 { - needTrailingSpace = !writeMoves(g.rootMove, - g.rootMove.Position().moveCount, - g.rootMove.Position().Turn() == White, &sb, false, false, true) - } else if g.rootMove.hasAnnotations() { - writeAnnotations(g.rootMove, &sb) - } - } - - // Append the game result. - if needTrailingSpace { - sb.WriteString(" ") - } - sb.WriteString(g.Outcome().String()) // outcomeString() returns the result as a string (e.g. "1-0") - return sb.String() + return DefaultPGNRenderer.Render(g) } -// sortableTagPair is its own -type sortableTagPair struct { - Key string - Value string +// WritePGN writes the game's PGN to w. It delegates to DefaultPGNRenderer +// and returns any write error. +func (g *Game) WritePGN(w io.Writer) error { + return DefaultPGNRenderer.RenderGameTo(g, w) } -// Compares two tags to determine in which order they should be brought up -func cmpTags(a, b sortableTagPair) int { - // Don't re-order duplicate keys - if a.Key == b.Key { - return 0 - } - - // PGN defined tags take priority - for _, req := range []string{ - "Event", - "Site", - "Date", - "Round", - "White", - "Black", - "Result", - } { - if a.Key == req { - return -1 - } - if b.Key == req { - return +1 - } - } - - // Finally compare the keys directly and sort by ascending - if a.Key < b.Key { - return -1 - } else if b.Key < a.Key { - return +1 - } - return 0 -} - -// writeMoves recursively writes the PGN-formatted move sequence starting from the given move node into the provided strings.Builder. -// It handles move numbering for white and black moves, encodes moves using algebraic notation based on the appropriate position, -// and appends comments and command annotations if present. The function distinguishes between main line moves and sub-variations; -// when processing a sub-variation, moves are enclosed in parentheses. -// -// Parameters: -// -// node - pointer to the current move node from which to write moves. -// moveNum - the current move number corresponding to white’s moves. -// isWhite - true if it is white’s move, false if it is black’s move. -// sb - pointer to a strings.Builder where the formatted move notation is appended. -// subVariation - true if the current call is within a sub-variation, affecting formatting details. -// closedVariation - true if the prior call closed a sub-variation, affecting formatting details. -// isRoot - true if the current move is the root move of a game, affecting formatting details. -// -// The function recurses through the move tree, writing the main line first and then processing any additional variations, -// ensuring that the output adheres to standard PGN conventions. Future enhancements may include support for all NAG values. -// the function returns whether or not a trailing space was added to the output -func writeMoves(node *Move, moveNum int, isWhite bool, sb *strings.Builder, - subVariation, closedVariation, isRoot bool, -) bool { - trailingSpace := false - - // If no moves remain, stop. - if node == nil { - return trailingSpace - } - - // Handle root move comments before processing children - if isRoot && node.hasAnnotations() { - writeAnnotations(node, sb) - } - - var currentMove *Move - - // The main line is the first child. - if subVariation { - currentMove = node - } else { - if len(node.children) == 0 { - return trailingSpace // nothing to print if no child exists (should not happen for a proper game) - } - currentMove = node.children[0] - } - - writeMoveNumber(moveNum, isWhite, subVariation, closedVariation, isRoot, sb) - - // Encode the move using your AlgebraicNotation. - writeMoveEncoding(node, currentMove, subVariation, sb) - - writeAnnotations(currentMove, sb) - - // TODO: Add support for all nags values in the future - - if len(node.children) > 1 || len(currentMove.children) > 0 { - sb.WriteString(" ") - } - // Process any variations (children beyond the first). - // In PGN, variations are enclosed in parentheses. - closedVar := writeVariations(node, moveNum, isWhite, sb) - - if len(currentMove.children) > 0 { - var nextMoveNum int - var nextIsWhite bool - if isWhite { - // After white's move, black plays using the same move number. - nextMoveNum = moveNum - nextIsWhite = false - } else { - // After black's move, increment move number. - nextMoveNum = moveNum + 1 - nextIsWhite = true - } - writeMoves(currentMove, nextMoveNum, nextIsWhite, sb, false, closedVar, - false) - } - - return trailingSpace -} - -func writeMoveNumber(moveNum int, isWhite bool, subVariation, closedVariation, - isRoot bool, sb *strings.Builder, -) { - if closedVariation { - sb.WriteString(" ") - } - if isWhite { - sb.WriteString(fmt.Sprintf("%d. ", moveNum)) - } else if subVariation || closedVariation || isRoot { - sb.WriteString(fmt.Sprintf("%d... ", moveNum)) - } -} - -func writeMoveEncoding(node *Move, currentMove *Move, subVariation bool, sb *strings.Builder) { - if subVariation && node.Parent() != nil { - moveStr := AlgebraicNotation{}.Encode(node.Parent().Position(), currentMove) - sb.WriteString(moveStr) - } else { - sb.WriteString(AlgebraicNotation{}.Encode(node.Position(), currentMove)) - } -} - -func sortedCommandKeys(commands map[string]string) []string { - keys := make([]string, 0, len(commands)) - for key := range commands { - keys = append(keys, key) - } - slices.Sort(keys) - return keys -} - -func writeAnnotations(move *Move, sb *strings.Builder) { - if move == nil { - return - } - - move.ensureCommentBlocksFromLegacy() - if len(move.commentBlocks) > 0 { - writeCommentBlocks(move.commentBlocks, sb) - return - } -} - -func writeCommentBlocks(blocks []CommentBlock, sb *strings.Builder) { - for _, block := range blocks { - if len(block.Items) == 0 { - continue - } - - sb.WriteString(" {") - for _, item := range block.Items { - switch item.Kind { - case CommentText: - sb.WriteString(item.Text) - case CommentCommand: - if needsCommandSeparator(sb) { - sb.WriteString(" ") - } - sb.WriteString("[%") - sb.WriteString(item.Key) - sb.WriteString(" ") - sb.WriteString(item.Value) - sb.WriteString("]") - } - } - sb.WriteString("}") - } -} - -func needsCommandSeparator(sb *strings.Builder) bool { - s := sb.String() - return len(s) > 0 && s[len(s)-1] != ' ' -} - -func writeVariations(node *Move, moveNum int, isWhite bool, sb *strings.Builder) bool { - wroteAtLeastOneVar := false - - if len(node.children) > 1 { - for i := 1; i < len(node.children); i++ { - if wroteAtLeastOneVar { - sb.WriteString(" ") - } - wroteAtLeastOneVar = true - - variation := node.children[i] - sb.WriteString("(") - writeMoves(variation, moveNum, isWhite, sb, true, false, false) - sb.WriteString(")") - } +// FEN returns the FEN notation of the current position. +// Returns "" if the game has no current position. +func (g *Game) FEN() string { + pos := g.currentPosition() + if pos == nil { + return "" } - - return wroteAtLeastOneVar + return pos.String() } // MarshalText implements the encoding.TextMarshaler interface and @@ -671,69 +213,16 @@ func (g *Game) MarshalText() ([]byte, error) { func (g *Game) UnmarshalText(text []byte) error { r := bytes.NewReader(text) - toGame, err := PGN(r) + game, err := ParsePGN(r) if err != nil { - return err + return fmt.Errorf("chess: unmarshal game PGN: %w", err) } - toGame(g) + g.copy(game) + g.tree = game.tree // parsed game is local; hand over the tree, do not share it return nil } -// Draw attempts to draw the game by the given method. If the -// method is valid, then the game is updated to a draw by that -// method. If the method isn't valid then an error is returned. -func (g *Game) Draw(method Method) error { - const halfMoveClockForFiftyMoveRule = 100 - const numOfRepetitionsForThreefoldRepetition = 3 - - switch method { - case ThreefoldRepetition: - if g.numOfRepetitions() < numOfRepetitionsForThreefoldRepetition { - return errors.New("chess: draw by ThreefoldRepetition requires at least three repetitions of the current board state") - } - case FiftyMoveRule: - if g.pos.halfMoveClock < halfMoveClockForFiftyMoveRule { - return errors.New("chess: draw by FiftyMoveRule requires a half move clock of 100 or greater") - } - case DrawOffer: - default: - return errors.New("chess: invalid draw method") - } - g.outcome = Draw - g.method = method - return nil -} - -// Resign resigns the game for the given color. If the game has -// already been completed then the game is not updated. -func (g *Game) Resign(color Color) { - if g.outcome != NoOutcome || color == NoColor { - return - } - if color == White { - g.outcome = BlackWon - } else { - g.outcome = WhiteWon - } - g.method = Resignation -} - -// EligibleDraws returns valid inputs for the Draw() method. -func (g *Game) EligibleDraws() []Method { - const halfMoveClockForFiftyMoveRule = 100 - const numOfRepetitionsForThreefoldRepetition = 3 - - draws := []Method{DrawOffer} - if g.numOfRepetitions() >= numOfRepetitionsForThreefoldRepetition { - draws = append(draws, ThreefoldRepetition) - } - if g.pos.halfMoveClock >= halfMoveClockForFiftyMoveRule { - draws = append(draws, FiftyMoveRule) - } - return draws -} - // AddTagPair adds or updates a tag pair with the given key and // value and returns true if the value is overwritten. func (g *Game) AddTagPair(k, v string) bool { @@ -765,427 +254,62 @@ func (g *Game) RemoveTagPair(k string) bool { return false } -// evaluatePositionStatus updates the game's outcome and method based on the current position. -func (g *Game) evaluatePositionStatus() { - method := g.pos.Status() - switch method { - case Stalemate: - g.method = Stalemate - g.outcome = Draw - case Checkmate: - g.method = Checkmate - g.outcome = WhiteWon - if g.pos.Turn() == White { - g.outcome = BlackWon - } - } - if g.outcome != NoOutcome { - return - } - - // five fold rep creates automatic draw - if !g.ignoreFivefoldRepetitionDraw && g.numOfRepetitions() >= 5 { - g.outcome = Draw - g.method = FivefoldRepetition - } - - // 75 move rule creates automatic draw - if !g.ignoreSeventyFiveMoveRuleDraw && g.pos.halfMoveClock >= 150 && g.method != Checkmate { - g.outcome = Draw - g.method = SeventyFiveMoveRule - } - - // insufficient material creates automatic draw - if !g.ignoreInsufficientMaterialDraw && !g.pos.board.hasSufficientMaterial() { - g.outcome = Draw - g.method = InsufficientMaterial - } -} - -// copy copies the game state from the given game. +// copy copies game state except the move tree from the given game. The caller +// must set g.tree explicitly; copy never aliases or clones it. func (g *Game) copy(game *Game) { - g.tagPairs = make(map[string]string) - for k, v := range game.tagPairs { - g.tagPairs[k] = v - } - g.rootMove = game.rootMove - g.currentMove = game.currentMove - g.pos = game.pos + g.tagPairs = maps.Clone(game.tagPairs) g.outcome = game.outcome g.method = game.method - g.comments = game.Comments() g.ignoreFivefoldRepetitionDraw = game.ignoreFivefoldRepetitionDraw g.ignoreSeventyFiveMoveRuleDraw = game.ignoreSeventyFiveMoveRuleDraw g.ignoreInsufficientMaterialDraw = game.ignoreInsufficientMaterialDraw } -// Clone returns a deep copy of the game. +// Clone returns a deep copy of the game, including its move tree. func (g *Game) Clone() *Game { ret := &Game{} ret.copy(g) - - // we have to also deep copy the moves so that modifications to the - // clone do not impact the parent - ret.rootMove = g.rootMove.Clone() - ret.rootMove.cloneChildren(g.rootMove.children) - if g.currentMove == nil { - ret.currentMove = ret.rootMove - } else { - ret.currentMove = findClonedMove(g.rootMove, ret.rootMove, g.currentMove) - if ret.currentMove == nil { - ret.currentMove = ret.rootMove - } - } - ret.pos = ret.currentMove.position + ret.tree = g.tree.Clone() // copy() skips tree; Clone deep-copies it return ret } -func findClonedMove(original, clone, target *Move) *Move { - if original == nil || clone == nil || target == nil { - return nil - } - if original == target { - return clone - } - for i, child := range original.children { - if i >= len(clone.children) { - return nil - } - if found := findClonedMove(child, clone.children[i], target); found != nil { - return found - } - } - return nil -} - // Positions returns all positions in the game in the main line. // This includes the starting position and all positions after each move. +// The cursor is saved and restored so the caller's active position is unchanged. func (g *Game) Positions() []*Position { - positions := make([]*Position, 0) - current := g.rootMove - - for current != nil { - if current.position != nil { - positions = append(positions, current.position) - } - if len(current.children) == 0 { - break + root := g.tree.Root() + if root == nil || len(root.children) == 0 { + return []*Position{} + } + defer g.tree.setCurrent(g.tree.Current()) + g.tree.Reset() + positions := make([]*Position, 0, len(root.children)+1) + if pos := g.tree.Peek(); pos != nil { + positions = append(positions, pos.copy()) + } + for g.tree.GoForward() { + if pos := g.tree.Peek(); pos != nil { + positions = append(positions, pos.copy()) } - current = current.children[0] } - return positions } func (g *Game) numOfRepetitions() int { count := 0 - for _, pos := range g.Positions() { - if pos == nil { - continue - } - if g.pos.samePosition(pos) { + target := g.currentPosition() + // numOfRepetitions walks the cursor through the main line; save and + // restore so callers see an unchanged active position. + defer g.tree.setCurrent(g.tree.Current()) + g.tree.Reset() + for { + if g.tree.pos != nil && target.SamePosition(g.tree.pos) { count++ } - } - return count -} - -// PushMoveOptions contains options for pushing a move to the game -type PushMoveOptions struct { - // ForceMainline makes this move the main line if variations exist - ForceMainline bool -} - -// Deprecated: use PushNotationMove instead. -// -// PushMove adds a move in algebraic notation to the game. -// Returns an error if the move is invalid. -// This method now validates moves for consistency with other move methods. -// -// Example: -// -// err := game.PushMove("e4", &PushMoveOptions{ForceMainline: true}) -func (g *Game) PushMove(algebraicMove string, options *PushMoveOptions) error { - return g.PushNotationMove(algebraicMove, AlgebraicNotation{}, options) -} - -// PushNotationMove adds a move to the game using any supported notation. -// It validates the move before adding it to ensure game correctness. -// For high-performance scenarios where moves are pre-validated, use UnsafePushNotationMove. -// -// Example: -// -// err := game.PushNotationMove("e4", chess.AlgebraicNotation{}, &PushMoveOptions{ForceMainline: true}) -// if err != nil { -// panic(err) -// } -// -// game.PushNotationMove("c7c5", chess.UCINotation{}, nil) -// game.PushNotationMove("Nc1f3", chess.LongAlgebraicNotation{}, nil) -func (g *Game) PushNotationMove(moveStr string, notation Notation, options *PushMoveOptions) error { - move, err := notation.Decode(g.pos, moveStr) - if err != nil { - return err - } - - return g.Move(move, options) -} - -// UnsafePushNotationMove adds a move to the game using any supported notation without validation. -// This method is intended for high-performance scenarios where moves are known to be valid. -// Use this method only when you have already validated the move or are certain it's legal. -// For general use, prefer PushNotationMove which includes validation. -// -// Example: -// -// // Only use when you're certain the move is valid -// err := game.UnsafePushNotationMove("e4", chess.AlgebraicNotation{}, nil) -// if err != nil { -// panic(err) // Should not happen with valid notation/moves -// } -func (g *Game) UnsafePushNotationMove(moveStr string, notation Notation, options *PushMoveOptions) error { - move, err := notation.Decode(g.pos, moveStr) - if err != nil { - return err - } - - return g.UnsafeMove(move, options) -} - -// Move method adds a move to the game using a Move struct. -// It returns an error if the move is invalid. -// This method validates the move before adding it to ensure game correctness. -// For high-performance scenarios where moves are pre-validated, use UnsafeMove. -// -// Example: -// -// possibleMove := game.ValidMoves()[0] -// -// err := game.Move(&possibleMove, nil) -// if err != nil { -// panic(err) -// } -func (g *Game) Move(move *Move, options *PushMoveOptions) error { - if options == nil { - options = &PushMoveOptions{} - } - - // Validate the move before adding it - if err := g.validateMove(move); err != nil { - return err - } - - return g.moveUnchecked(move, options) -} - -// UnsafeMove adds a move to the game without validation. -// This method is intended for high-performance scenarios where moves are known to be valid. -// Use this method only when you have already validated the move or are certain it's legal. -// For general use, prefer the Move method which includes validation. -// -// Example: -// -// // Only use when you're certain the move is valid -// validMoves := game.ValidMoves() -// move := &validMoves[0] // We know this is valid -// err := game.UnsafeMove(move, nil) -// if err != nil { -// panic(err) // Should not happen with valid moves -// } -func (g *Game) UnsafeMove(move *Move, options *PushMoveOptions) error { - if options == nil { - options = &PushMoveOptions{} - } - - return g.moveUnchecked(move, options) -} - -// moveUnchecked is the internal implementation that performs the move without validation. -// This is shared by both Move (after validation) and MoveUnchecked. -func (g *Game) moveUnchecked(move *Move, options *PushMoveOptions) error { - if move == nil { - return errors.New("move cannot be nil") - } - - existingMove := g.findExistingMove(move) - g.addOrReorderMove(move, existingMove, options.ForceMainline) - - g.updatePosition(move) - g.currentMove = move - - g.evaluatePositionStatus() - - return nil -} - -// validateMove checks if the given move is valid for the current position. -// It returns an error if the move is invalid. -func (g *Game) validateMove(move *Move) error { - if move == nil { - return errors.New("move cannot be nil") - } - - if g.pos == nil { - return errors.New("no current position") - } - - // Check if the move exists in the list of valid moves for the current position - validMoves := g.pos.ValidMovesUnsafe() - for _, validMove := range validMoves { - if validMove.s1 == move.s1 && validMove.s2 == move.s2 && validMove.promo == move.promo { - return nil // Move is valid - } - } - - return fmt.Errorf("move %s is not valid for the current position", move.String()) -} - -func (g *Game) findExistingMove(move *Move) *Move { - if g.currentMove == nil { - return nil - } - for _, child := range g.currentMove.children { - if child.s1 == move.s1 && child.s2 == move.s2 && child.promo == move.promo { - return child - } - } - return nil -} - -func (g *Game) addOrReorderMove(move, existingMove *Move, forceMainline bool) { - move.parent = g.currentMove - - if existingMove != nil { - if forceMainline && existingMove != g.currentMove.children[0] { - g.reorderMoveToFront(existingMove) - } - } else { - g.addNewMove(move, forceMainline) - } -} - -func (g *Game) reorderMoveToFront(move *Move) { - children := g.currentMove.children - for i, child := range children { - if child == move { - copy(children[1:i+1], children[:i]) - children[0] = move + if !g.tree.GoForward() { break } } -} - -func (g *Game) addNewMove(move *Move, forceMainline bool) { - if forceMainline { - g.currentMove.children = append([]*Move{move}, g.currentMove.children...) - } else { - g.currentMove.children = append(g.currentMove.children, move) - } -} - -func (g *Game) updatePosition(move *Move) { - if newPos := g.pos.Update(move); newPos != nil { - g.pos = newPos - move.position = newPos - } -} - -// Split takes a Game with a main line and 0 or more variations and returns a -// slice of Games (one for each variation), each containing exactly only a main -// line and 0 variations -func (g *Game) Split() []*Game { - // Collect all move paths starting from the root's children - var paths [][]*Move - for _, m := range g.rootMove.children { - paths = append(paths, collectPaths(m)...) - } - - // Build a Game for each path - var games []*Game - for _, path := range paths { - newG := g.buildOneGameFromPath(path) - games = append(games, newG) - } - - return games -} - -// collectPaths returns all paths from the given move to each leaf node. -// Each path is represented as a slice of *Move, starting with the given node -// and ending with a leaf (a move with no children). -func collectPaths(node *Move) [][]*Move { - if node == nil { - return nil - } - // If leaf, return a single path containing this node - if len(node.children) == 0 { - return [][]*Move{{node}} - } - // Otherwise, collect paths from each child and prepend this node - var paths [][]*Move - for _, c := range node.children { - childPaths := collectPaths(c) - for _, p := range childPaths { - path := append([]*Move{node}, p...) - paths = append(paths, path) - } - } - return paths -} - -func (g *Game) buildOneGameFromPath(path []*Move) *Game { - rootMove := &Move{position: g.rootMove.position.copy()} - cur := rootMove - - for _, m := range path { - child := m.Clone() - child.parent = cur - - cur.children = []*Move{child} - cur = child - } - - newG := &Game{} - newG.copy(g) - newG.rootMove = rootMove - newG.currentMove = cur - newG.pos = cur.position - - return newG -} - -// ValidateSAN checks if a string is valid Standard Algebraic Notation (SAN) syntax. -// This function only validates the syntax, not whether the move is legal in any position. -// Examples of valid SAN: "e4", "Nf3", "O-O", "Qxd2+", "e8=Q#" -func ValidateSAN(s string) error { - _, err := algebraicNotationParts(s) - return err -} - -// IgnoreFivefoldRepetitionDraw returns a Game option that disables automatic draws -// caused by the fivefold repetition rule. When applied, the game will not -// automatically end in a draw if the same position occurs five times. -func IgnoreFivefoldRepetitionDraw() func(*Game) { - return func(g *Game) { - g.ignoreFivefoldRepetitionDraw = true - } -} - -// IgnoreSeventyFiveMoveRuleDraw returns a Game option that disables automatic draws -// triggered by the seventy-five move rule. When applied, the game will not -// automatically end in a draw if one hundred fifty half-moves pass without a pawn move or capture. -func IgnoreSeventyFiveMoveRuleDraw() func(*Game) { - return func(g *Game) { - g.ignoreSeventyFiveMoveRuleDraw = true - } -} - -// IgnoreInsufficientMaterialDraw returns a Game option that disables automatic draws -// caused by insufficient material. When applied, the game will not automatically -// end in a draw even if checkmate is impossible with the remaining pieces. -func IgnoreInsufficientMaterialDraw() func(*Game) { - return func(g *Game) { - g.ignoreInsufficientMaterialDraw = true - } + return count } diff --git a/game_invariants_test.go b/game_invariants_test.go index 6575d3f5..6b501a6f 100644 --- a/game_invariants_test.go +++ b/game_invariants_test.go @@ -5,76 +5,119 @@ import ( "testing" ) -func assertGameCurrentPositionInvariant(t *testing.T, g *Game) { +func assertGameTreeCurrentPositionInvariant(t *testing.T, g *Game) { t.Helper() if g == nil { t.Fatal("game is nil") } - if g.pos == nil { - t.Fatal("game current position is nil") + if g.currentPosition() == nil { + t.Fatal("tree current position is nil") } if g.Position() == nil { t.Fatal("Position() is nil") } - if g.CurrentPosition() == nil { - t.Fatal("CurrentPosition() is nil") + if g.MoveTree().Current().Position() == nil { + t.Fatal("MoveTree().Current().Position() is nil") } - if g.Position().String() != g.pos.String() { - t.Fatalf("Position() = %q, want game current position %q", g.Position(), g.pos) + if g.Position().String() != g.currentPosition().String() { + t.Fatalf("Position() = %q, want tree current position %q", g.Position(), g.currentPosition()) } - if g.CurrentPosition().String() != g.pos.String() { - t.Fatalf("CurrentPosition() = %q, want game current position %q", g.CurrentPosition(), g.pos) - } - if g.currentMove != nil && g.currentMove.position != nil && g.currentMove.position.String() != g.pos.String() { - t.Fatalf("current move position = %q, want game current position %q", g.currentMove.position, g.pos) + if g.MoveTree().Current().Position().String() != g.currentPosition().String() { + t.Fatalf("MoveTree().Current().Position() = %q, want tree current position %q", g.MoveTree().Current().Position(), g.currentPosition()) } } -func TestGameCurrentPositionInvariantAfterClonePreservesCursor(t *testing.T) { +func TestGameTreeCurrentPositionInvariantAfterClonePreservesCursor(t *testing.T) { g := NewGame() for _, move := range []string{"e4", "e5", "Nf3"} { - if err := g.PushMove(move, nil); err != nil { + if _, err := g.MoveText(move, SAN(), nil); err != nil { t.Fatal(err) } } - if !g.GoBack() { + if !g.MoveTree().GoBack() { t.Fatal("expected to navigate back") } - want := g.CurrentPosition().String() + want := g.MoveTree().Current().Position().String() clone := g.Clone() - assertGameCurrentPositionInvariant(t, clone) - if got := clone.CurrentPosition().String(); got != want { + assertGameTreeCurrentPositionInvariant(t, clone) + if got := clone.MoveTree().Current().Position().String(); got != want { t.Fatalf("clone current position = %q, want %q", got, want) } } -func TestGameCurrentPositionInvariantAfterDirectGameOperations(t *testing.T) { +func TestGameTreeCurrentPositionInvariantAfterDirectGameOperations(t *testing.T) { g := NewGame() - assertGameCurrentPositionInvariant(t, g) + assertGameTreeCurrentPositionInvariant(t, g) for _, move := range []string{"e4", "e5", "Nf3"} { - if err := g.PushMove(move, nil); err != nil { + if _, err := g.MoveText(move, SAN(), nil); err != nil { t.Fatal(err) } - assertGameCurrentPositionInvariant(t, g) + assertGameTreeCurrentPositionInvariant(t, g) } - if !g.GoBack() { + if !g.MoveTree().GoBack() { t.Fatal("expected to navigate back") } - assertGameCurrentPositionInvariant(t, g) + assertGameTreeCurrentPositionInvariant(t, g) + + if !g.MoveTree().GoForward() { + t.Fatal("expected to navigate forward") + } + assertGameTreeCurrentPositionInvariant(t, g) +} + +func TestPositionReturnsDefensiveCopyAfterGoForward(t *testing.T) { + g := NewGame() + for _, move := range []string{"e4", "e5"} { + if _, err := g.MoveText(move, SAN(), nil); err != nil { + t.Fatal(err) + } + } - if !g.GoForward() { + if !g.MoveTree().GoBack() { + t.Fatal("expected to navigate back") + } + if !g.MoveTree().GoForward() { t.Fatal("expected to navigate forward") } - assertGameCurrentPositionInvariant(t, g) + if g.Position() == g.MoveTree().Current().Position() { + t.Fatal("Position shared current position pointer with move node") + } + assertGameTreeCurrentPositionInvariant(t, g) +} + +func TestAddVariationStoresPosition(t *testing.T) { + g := NewGame() + move, err := decodeSANText(g.Position(), "e4", true) + if err != nil { + t.Fatal(err) + } + + if _, err := g.MoveTree().AddVariation(nil, move); err != nil { + t.Fatal(err) + } + children := g.MoveTree().Root().Children() + if len(children) != 1 { + t.Fatalf("root children = %d, want 1", len(children)) + } + if children[0].Position() == nil { + t.Fatal("variation position is nil") + } + if got, want := children[0].Position().String(), g.Position().Update(move).String(); got != want { + t.Fatalf("variation position = %q, want %q", got, want) + } + if !g.MoveTree().GoForward() { + t.Fatal("expected to navigate into variation") + } + assertGameTreeCurrentPositionInvariant(t, g) } -func TestGameCurrentPositionInvariantAfterPGNParse(t *testing.T) { +func TestGameTreeCurrentPositionInvariantAfterPGNParse(t *testing.T) { opt, err := PGN(strings.NewReader("1. e4 e5 2. Nf3 *")) if err != nil { t.Fatal(err) @@ -82,21 +125,38 @@ func TestGameCurrentPositionInvariantAfterPGNParse(t *testing.T) { g := NewGame(opt) - assertGameCurrentPositionInvariant(t, g) + assertGameTreeCurrentPositionInvariant(t, g) +} + +func TestGameTreeCurrentPositionInvariantAfterPGNParseWithNestedVariations(t *testing.T) { + opt, err := PGN(strings.NewReader("1. e4 (1. d4 d5 (1... Nf6)) e5 2. Nf3 *")) + if err != nil { + t.Fatal(err) + } + + g := NewGame(opt) + + assertGameTreeCurrentPositionInvariant(t, g) + if !g.IsAtEnd() { + t.Fatalf("parsed tree current = %s, want main-line leaf", g.MoveTree().Current().Move()) + } + if got, want := len(g.MoveTree().Variations(g.MoveTree().Root())), 1; got != want { + t.Fatalf("root variations = %d, want %d", got, want) + } } -func TestGameCurrentPositionInvariantAfterSplitUsesLineLeaf(t *testing.T) { +func TestGameTreeCurrentPositionInvariantAfterSplitUsesLineLeaf(t *testing.T) { g := NewGame() for _, move := range []string{"e4", "e5", "Nf3"} { - if err := g.PushMove(move, nil); err != nil { + if _, err := g.MoveText(move, SAN(), nil); err != nil { t.Fatal(err) } } - if !g.GoBack() { + if !g.MoveTree().GoBack() { t.Fatal("expected to navigate back before adding a variation") } - if err := g.PushMove("Nc3", nil); err != nil { + if _, err := g.MoveText("Nc3", SAN(), nil); err != nil { t.Fatal(err) } @@ -105,9 +165,9 @@ func TestGameCurrentPositionInvariantAfterSplitUsesLineLeaf(t *testing.T) { t.Fatalf("split game count = %d, want 2", len(splitGames)) } for _, splitGame := range splitGames { - assertGameCurrentPositionInvariant(t, splitGame) + assertGameTreeCurrentPositionInvariant(t, splitGame) if !splitGame.IsAtEnd() { - t.Fatalf("split game current position = %q, want leaf position", splitGame.CurrentPosition()) + t.Fatalf("split tree current position = %q, want leaf position", splitGame.MoveTree().Current().Position()) } } } diff --git a/game_move.go b/game_move.go new file mode 100644 index 00000000..7c95b63e --- /dev/null +++ b/game_move.go @@ -0,0 +1,186 @@ +package chess + +import ( + "cmp" + "errors" + "fmt" +) + +// MoveText adds a move to the game using an explicit move text codec. +// It decodes against the current position so the inserted move carries +// position-derived tags. The decoded Move is canonical (codec.Decode resolves +// legal moves), so it crosses the trusted fast path: no extra legal-move +// lookup is needed before insertion. +func (g *Game) MoveText(moveText string, codec MoveTextCodec, options *MoveInsertOptions) (*MoveNode, error) { + move, err := codec.Decode(g.currentPosition(), moveText) + if err != nil { + return nil, fmt.Errorf("chess: decode %s move text %q: %w", codec, moveText, err) + } + + return g.insertCanonical(canonicalMoveFromCodec(move), options) +} + +// UnsafeMoveText adds fully specified move text without legal move +// verification. It supports only codecs that can raw-decode a move without SAN +// resolution. +func (g *Game) UnsafeMoveText(moveText string, codec MoveTextCodec, options *MoveInsertOptions) (*MoveNode, error) { + raw, err := codec.DecodeRaw(moveText) + if err != nil { + if errors.Is(err, ErrMoveTextUnsupportedRawDecode) { + return nil, fmt.Errorf("%w: %s", ErrUnsafeMoveTextUnsupported, codec) + } + return nil, fmt.Errorf("chess: decode raw %s move text %q: %w", codec, moveText, err) + } + + move := raw.Move() + if !move.HasTag(Null) { + pos := g.currentPosition() + if pos == nil { + return nil, ErrMoveTextMissingPosition + } + tag, _ := newLegality(pos, generateLegalAnnotated).legal(move) + move.tags = tag + } + + return g.UnsafeMove(move, options) +} + +// canonicalMoveFromCodec returns the codec-decoded Move, normalising any +// stray Null-tagged value through NewNullMove so the Move tree only ever +// stores the canonical Null shape. +func canonicalMoveFromCodec(m Move) Move { + if m.HasTag(Null) { + return NewNullMove() + } + return m +} + +// insertCanonical inserts an already-resolved canonical Move without +// re-running the legal-move scan. Move tree repair-or-reject semantics still +// apply for existing Move occurrences with stale tags. +func (g *Game) insertCanonical(canonical Move, options *MoveInsertOptions) (*MoveNode, error) { + options = cmp.Or(options, &MoveInsertOptions{}) + return g.moveUnchecked(canonical, options) +} + +// PushMove adds a move in algebraic notation to the game. +// Returns an error if the move is invalid. +// +// Deprecated: use MoveText(algebraicMove, SAN(), options) instead. +func (g *Game) PushMove(algebraicMove string, options *MoveInsertOptions) (*MoveNode, error) { + return g.MoveText(algebraicMove, SAN(), options) +} + +// PushMoveText adds a move to the game using an explicit move text codec. +// +// Deprecated: use MoveText instead. +func (g *Game) PushMoveText(moveText string, codec MoveTextCodec, options *MoveInsertOptions) (*MoveNode, error) { + return g.MoveText(moveText, codec, options) +} + +// UnsafePushMoveText adds fully specified move text without legal move +// verification. +// +// Deprecated: use UnsafeMoveText instead. +func (g *Game) UnsafePushMoveText(moveText string, codec MoveTextCodec, options *MoveInsertOptions) (*MoveNode, error) { + return g.UnsafeMoveText(moveText, codec, options) +} + +// Move method adds a move to the game using a Move struct. +// It returns an error if the move is invalid. +// This method validates the move before adding it to ensure game correctness. +// For high-performance scenarios where moves are pre-validated, use UnsafeMove. +// +// Null moves are rejected here: they are never part of ValidMovesUnsafe, so +// callers wanting to pass the side must use [Game.NullMove] or +// [Game.UnsafeMove] explicitly. +// +// Example: +// +// possibleMove := game.ValidMoves()[0] +// +// err := game.Move(possibleMove, nil) +// if err != nil { +// panic(err) +// } +func (g *Game) Move(move Move, options *MoveInsertOptions) (*MoveNode, error) { + options = cmp.Or(options, &MoveInsertOptions{}) + + if move.HasTag(Null) { + return nil, errors.New("chess: null move is not valid for the current position") + } + + canonical, err := resolveCanonicalMove(g.currentPosition(), move) + if err != nil { + return nil, err + } + + return g.moveUnchecked(canonical, options) +} + +// UnsafeMove adds a move to the game without validation. +// This method is intended for high-performance scenarios where moves are known to be valid. +// Use this method only when you have already validated the move or are certain it's legal. +// For general use, prefer the Move method which includes validation. +// +// Example: +// +// // Only use when you're certain the move is valid +// validMoves := game.ValidMoves() +// move := validMoves[0] // We know this is valid +// err := game.UnsafeMove(move, nil) +// if err != nil { +// panic(err) // Should not happen with valid moves +// } +func (g *Game) UnsafeMove(move Move, options *MoveInsertOptions) (*MoveNode, error) { + options = cmp.Or(options, &MoveInsertOptions{}) + + return g.moveUnchecked(move, options) +} + +// moveUnchecked is the internal implementation that performs the move without validation. +// This is shared by both Move (after validation) and MoveUnchecked. +func (g *Game) moveUnchecked(move Move, options *MoveInsertOptions) (*MoveNode, error) { + if g.outcome != NoOutcome { + return nil, ErrGameAlreadyEnded + } + + node, err := g.tree.addMove(move, options) + if err != nil { + return nil, err + } + + g.evaluatePositionStatus() + + return node, nil +} + +// NullMove appends a null move (a side-to-move flip with no piece movement) +// to the current position's main line. Null moves are never part of the +// legal moves returned by ValidMoves, so they cannot be inserted via Game.Move. +// Use this method or Game.UnsafeMove(NullMove()) to add one explicitly. +// +// Pass nil (or no argument) to use default options. +func (g *Game) NullMove(options ...*MoveInsertOptions) (*MoveNode, error) { + var opts *MoveInsertOptions + if len(options) > 0 { + opts = options[0] + } + return g.insertByMove(NewNullMove(), opts) +} + +// insertByMove is shared by UnsafeMove and NullMove. It validates only the +// structural preconditions (game in progress) and lets moveUnchecked handle +// tree wiring and position updates. +func (g *Game) insertByMove(move Move, options *MoveInsertOptions) (*MoveNode, error) { + options = cmp.Or(options, &MoveInsertOptions{}) + return g.moveUnchecked(move, options) +} + +// ValidateSAN checks if a string is valid Standard Algebraic notation (SAN) syntax. +// This function only validates the syntax, not whether the move is legal in any position. +// Examples of valid SAN: "e4", "Nf3", "O-O", "Qxd2+", "e8=Q#". +func ValidateSAN(s string) error { + _, err := algebraicNotationParts(s) + return err +} diff --git a/game_move_text_test.go b/game_move_text_test.go new file mode 100644 index 00000000..1566f12c --- /dev/null +++ b/game_move_text_test.go @@ -0,0 +1,78 @@ +package chess_test + +import ( + "testing" + + "github.com/corentings/chess/v3" +) + +func TestGamePushMoveTextWithCodecs(t *testing.T) { + tests := []struct { + name string + codec chess.MoveTextCodec + text string + want string + }{ + { + name: "SAN", + codec: chess.SAN(), + text: "e4", + want: "1. e4 *", + }, + { + name: "UCI", + codec: chess.UCI(), + text: "e2e4", + want: "1. e4 *", + }, + { + name: "long algebraic", + codec: chess.LongAlgebraic(), + text: "e2e4", + want: "1. e4 *", + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + game := chess.NewGame() + if _, err := game.MoveText(tt.text, tt.codec, nil); err != nil { + t.Fatalf("MoveText() error = %v", err) + } + if got := game.String(); got != tt.want { + t.Fatalf("game.String() = %q, want %q", got, tt.want) + } + }) + } +} + +func TestGamePushMoveTextUsesGeneratedMoveTags(t *testing.T) { + game := chess.NewGame() + if _, err := game.MoveText("e2e4", chess.UCI(), nil); err != nil { + t.Fatalf("MoveText(e2e4) error = %v", err) + } + if _, err := game.MoveText("d7d5", chess.UCI(), nil); err != nil { + t.Fatalf("MoveText(d7d5) error = %v", err) + } + node, err := game.MoveText("e4d5", chess.UCI(), nil) + if err != nil { + t.Fatalf("MoveText(e4d5) error = %v", err) + } + if !node.Move().HasTag(chess.Capture) { + t.Fatalf("inserted move missing Capture tag: %v", node.Move()) + } + if got := game.String(); got != "1. e4 d5 2. exd5 *" { + t.Fatalf("game.String() = %q, want capture SAN", got) + } +} + +func TestGamePushMoveIsStrictSANShorthand(t *testing.T) { + opt, err := chess.FEN("6k1/4P3/8/8/8/8/8/4K3 w - - 0 1") + if err != nil { + t.Fatalf("FEN() error = %v", err) + } + game := chess.NewGame(opt) + if _, err := game.MoveText("e8Q", chess.SAN(), nil); err == nil { + t.Fatalf("PushMove accepted import-only SAN") + } +} diff --git a/game_outcome.go b/game_outcome.go new file mode 100644 index 00000000..76a68414 --- /dev/null +++ b/game_outcome.go @@ -0,0 +1,151 @@ +package chess + +import ( + "errors" + "fmt" +) + +// OutcomeMethodPair pairs an Outcome with the Method that produced it. +type OutcomeMethodPair struct { + Outcome Outcome + Method Method +} + +// SetOutcomeMethod sets the game's outcome and method together after validating +// that the pair is internally consistent. It returns an error for invalid pairs +// such as WhiteWon with Stalemate or Draw with Checkmate. It does not modify +// any Result tag in tagPairs. +func (g *Game) SetOutcomeMethod(pair OutcomeMethodPair) error { + if !validOutcomeMethodPair(pair) { + return fmt.Errorf("chess: invalid outcome/method pair: outcome=%s method=%s", pair.Outcome, pair.Method) + } + g.outcome = pair.Outcome + g.method = pair.Method + return nil +} + +func validOutcomeMethodPair(pair OutcomeMethodPair) bool { + switch pair.Outcome { + case NoOutcome: + return pair.Method == NoMethod + case WhiteWon, BlackWon: + switch pair.Method { + case NoMethod, Checkmate, Resignation: + return true + } + case Draw: + switch pair.Method { + case NoMethod, DrawOffer, Stalemate, ThreefoldRepetition, + FivefoldRepetition, FiftyMoveRule, SeventyFiveMoveRule, InsufficientMaterial: + return true + } + } + return false +} + +// ClearOutcome resets the game to NoOutcome/NoMethod. It does not modify any +// tag in tagPairs (including the Result tag): PGN tag metadata is treated as +// caller-owned data, separate from the live outcome. Callers that want PGN +// tag parity must update tagPairs["Result"] themselves, or rebuild from the +// game state via Split which does sync the tag. +func (g *Game) ClearOutcome() { + g.outcome = NoOutcome + g.method = NoMethod +} + +// Draw attempts to draw the game by the given method. If the +// method is valid, then the game is updated to a draw by that +// method. If the method isn't valid then an error is returned. +// Returns ErrGameAlreadyEnded if the game is already in a terminal state. +func (g *Game) Draw(method Method) error { + const halfMoveClockForFiftyMoveRule = 100 + const numOfRepetitionsForThreefoldRepetition = 3 + + if g.outcome != NoOutcome { + return ErrGameAlreadyEnded + } + switch method { + case ThreefoldRepetition: + if g.numOfRepetitions() < numOfRepetitionsForThreefoldRepetition { + return errors.New("chess: draw by ThreefoldRepetition requires at least three repetitions of the current board state") + } + case FiftyMoveRule: + if g.currentPosition().halfMoveClock < halfMoveClockForFiftyMoveRule { + return errors.New("chess: draw by FiftyMoveRule requires a half move clock of 100 or greater") + } + case DrawOffer: + default: + return errors.New("chess: invalid draw method") + } + g.outcome = Draw + g.method = method + return nil +} + +// Resign resigns the game for the given color. If the game has +// already been completed or the color is invalid, Resign returns an error +// and does not update the game. +func (g *Game) Resign(color Color) error { + if color == NoColor { + return errors.New("chess: cannot resign with NoColor") + } + if g.outcome != NoOutcome { + return ErrGameAlreadyEnded + } + if color == White { + g.outcome = BlackWon + } else { + g.outcome = WhiteWon + } + g.method = Resignation + return nil +} + +// EligibleDraws returns valid inputs for the Draw() method. +func (g *Game) EligibleDraws() []Method { + const halfMoveClockForFiftyMoveRule = 100 + const numOfRepetitionsForThreefoldRepetition = 3 + + draws := []Method{DrawOffer} + if g.numOfRepetitions() >= numOfRepetitionsForThreefoldRepetition { + draws = append(draws, ThreefoldRepetition) + } + if g.currentPosition().halfMoveClock >= halfMoveClockForFiftyMoveRule { + draws = append(draws, FiftyMoveRule) + } + return draws +} + +// evaluatePositionStatus updates the game's outcome and method based on the +// current position. It runs the Full outcome policy (all automatic draws, +// honouring the Game's ignore flags) and is called after every Move and FEN. +func (g *Game) evaluatePositionStatus() { + g.outcome, g.method = classifyOutcome(g.currentPosition(), g.numOfRepetitions(), fullOutcomeRules(g)) +} + +// IgnoreFivefoldRepetitionDraw returns a Game option that disables automatic draws +// caused by the fivefold repetition rule. When applied, the game will not +// automatically end in a draw if the same position occurs five times. +func IgnoreFivefoldRepetitionDraw() func(*Game) { + return func(g *Game) { + g.ignoreFivefoldRepetitionDraw = true + } +} + +// IgnoreSeventyFiveMoveRuleDraw returns a Game option that disables automatic draws +// triggered by the seventy-five move rule. When applied, the game will not +// automatically end in a draw if one hundred fifty half-moves pass without a pawn move or capture. +func IgnoreSeventyFiveMoveRuleDraw() func(*Game) { + return func(g *Game) { + g.ignoreSeventyFiveMoveRuleDraw = true + } +} + +// IgnoreInsufficientMaterialDraw returns a Game option that disables automatic draws +// caused by insufficient material. When applied, the game will not automatically +// end in a draw even if checkmate is impossible with the remaining pieces. +func IgnoreInsufficientMaterialDraw() func(*Game) { + return func(g *Game) { + g.ignoreInsufficientMaterialDraw = true + } +} diff --git a/game_outcome_method_test.go b/game_outcome_method_test.go new file mode 100644 index 00000000..90f74f14 --- /dev/null +++ b/game_outcome_method_test.go @@ -0,0 +1,334 @@ +package chess_test + +import ( + "errors" + "fmt" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +func ExampleGame_SetOutcomeMethod() { + g := chess.NewGame() + if err := g.SetOutcomeMethod(chess.OutcomeMethodPair{ + Outcome: chess.WhiteWon, + Method: chess.Resignation, + }); err != nil { + fmt.Println("Error:", err) + return + } + fmt.Println(g.Outcome(), g.Method()) + // Output: 1-0 Resignation +} + +func TestSetOutcomeMethod(t *testing.T) { + tests := []struct { + name string + pair chess.OutcomeMethodPair + wantErr bool + }{ + {"NoOutcome/NoMethod", chess.OutcomeMethodPair{chess.NoOutcome, chess.NoMethod}, false}, + {"NoOutcome/Checkmate", chess.OutcomeMethodPair{chess.NoOutcome, chess.Checkmate}, true}, + {"NoOutcome/Stalemate", chess.OutcomeMethodPair{chess.NoOutcome, chess.Stalemate}, true}, + {"NoOutcome/Resignation", chess.OutcomeMethodPair{chess.NoOutcome, chess.Resignation}, true}, + {"WhiteWon/NoMethod", chess.OutcomeMethodPair{chess.WhiteWon, chess.NoMethod}, false}, + {"WhiteWon/Checkmate", chess.OutcomeMethodPair{chess.WhiteWon, chess.Checkmate}, false}, + {"WhiteWon/Resignation", chess.OutcomeMethodPair{chess.WhiteWon, chess.Resignation}, false}, + {"WhiteWon/Stalemate", chess.OutcomeMethodPair{chess.WhiteWon, chess.Stalemate}, true}, + {"WhiteWon/DrawOffer", chess.OutcomeMethodPair{chess.WhiteWon, chess.DrawOffer}, true}, + {"WhiteWon/FiftyMoveRule", chess.OutcomeMethodPair{chess.WhiteWon, chess.FiftyMoveRule}, true}, + {"BlackWon/NoMethod", chess.OutcomeMethodPair{chess.BlackWon, chess.NoMethod}, false}, + {"BlackWon/Checkmate", chess.OutcomeMethodPair{chess.BlackWon, chess.Checkmate}, false}, + {"BlackWon/Resignation", chess.OutcomeMethodPair{chess.BlackWon, chess.Resignation}, false}, + {"BlackWon/Stalemate", chess.OutcomeMethodPair{chess.BlackWon, chess.Stalemate}, true}, + {"BlackWon/InsufficientMaterial", chess.OutcomeMethodPair{chess.BlackWon, chess.InsufficientMaterial}, true}, + {"Draw/NoMethod", chess.OutcomeMethodPair{chess.Draw, chess.NoMethod}, false}, + {"Draw/DrawOffer", chess.OutcomeMethodPair{chess.Draw, chess.DrawOffer}, false}, + {"Draw/Stalemate", chess.OutcomeMethodPair{chess.Draw, chess.Stalemate}, false}, + {"Draw/ThreefoldRepetition", chess.OutcomeMethodPair{chess.Draw, chess.ThreefoldRepetition}, false}, + {"Draw/FivefoldRepetition", chess.OutcomeMethodPair{chess.Draw, chess.FivefoldRepetition}, false}, + {"Draw/FiftyMoveRule", chess.OutcomeMethodPair{chess.Draw, chess.FiftyMoveRule}, false}, + {"Draw/SeventyFiveMoveRule", chess.OutcomeMethodPair{chess.Draw, chess.SeventyFiveMoveRule}, false}, + {"Draw/InsufficientMaterial", chess.OutcomeMethodPair{chess.Draw, chess.InsufficientMaterial}, false}, + {"Draw/Checkmate", chess.OutcomeMethodPair{chess.Draw, chess.Checkmate}, true}, + {"Draw/Resignation", chess.OutcomeMethodPair{chess.Draw, chess.Resignation}, true}, + {"NoOutcome/NoMethod", chess.OutcomeMethodPair{chess.NoOutcome, chess.NoMethod}, false}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + g := chess.NewGame() + err := g.SetOutcomeMethod(tt.pair) + if tt.wantErr { + if err == nil { + t.Fatalf("expected error, got nil") + } + if g.Outcome() != chess.NoOutcome { + t.Errorf("Outcome = %v after rejection, want NoOutcome", g.Outcome()) + } + if g.Method() != chess.NoMethod { + t.Errorf("Method = %v after rejection, want NoMethod", g.Method()) + } + return + } + if err != nil { + t.Fatalf("unexpected error: %v", err) + } + if g.Outcome() != tt.pair.Outcome { + t.Errorf("Outcome = %v, want %v", g.Outcome(), tt.pair.Outcome) + } + if g.Method() != tt.pair.Method { + t.Errorf("Method = %v, want %v", g.Method(), tt.pair.Method) + } + }) + } +} + +func TestTerminalOutcomeGuards(t *testing.T) { + setups := map[string]func(t *testing.T, g *chess.Game){ + "via_SetOutcomeMethod": func(t *testing.T, g *chess.Game) { + t.Helper() + if err := g.SetOutcomeMethod(chess.OutcomeMethodPair{chess.WhiteWon, chess.Checkmate}); err != nil { + t.Fatal(err) + } + }, + "via_Resign": func(t *testing.T, g *chess.Game) { + t.Helper() + if err := g.Resign(chess.White); err != nil { + t.Fatal(err) + } + }, + "via_Draw": func(t *testing.T, g *chess.Game) { + t.Helper() + if err := g.Draw(chess.DrawOffer); err != nil { + t.Fatal(err) + } + }, + } + actions := []struct { + name string + call func(g *chess.Game) error + }{ + {"Move", func(g *chess.Game) error { _, err := g.Move(g.ValidMoves()[0], nil); return err }}, + {"UnsafeMove", func(g *chess.Game) error { _, err := g.UnsafeMove(g.ValidMoves()[0], nil); return err }}, + {"PushMove", func(g *chess.Game) error { _, err := g.MoveText("e4", chess.SAN(), nil); return err }}, + {"PushMoveText", func(g *chess.Game) error { + _, err := g.MoveText("e4", chess.SAN(), nil) + return err + }}, + {"UnsafePushMoveText", func(g *chess.Game) error { + _, err := g.UnsafeMoveText("e2e4", chess.UCI(), nil) + return err + }}, + {"Resign", func(g *chess.Game) error { return g.Resign(chess.Black) }}, + {"Draw", func(g *chess.Game) error { return g.Draw(chess.DrawOffer) }}, + } + for setupName, setup := range setups { + t.Run(setupName, func(t *testing.T) { + for _, act := range actions { + t.Run(act.name, func(t *testing.T) { + g := chess.NewGame() + setup(t, g) + err := act.call(g) + if !errors.Is(err, chess.ErrGameAlreadyEnded) { + t.Errorf("%s after terminal: error = %v, want ErrGameAlreadyEnded", act.name, err) + } + }) + } + }) + } +} + +func TestResignWithNoColorReturnsError(t *testing.T) { + g := chess.NewGame() + err := g.Resign(chess.NoColor) + if err == nil { + t.Fatal("expected error when resigning with NoColor, got nil") + } + if g.Outcome() != chess.NoOutcome { + t.Errorf("Outcome = %s, want NoOutcome", g.Outcome()) + } +} + +func TestResignSetsOpponentWinner(t *testing.T) { + g := chess.NewGame() + if err := g.Resign(chess.White); err != nil { + t.Fatal(err) + } + if g.Outcome() != chess.BlackWon { + t.Errorf("Outcome = %v, want BlackWon", g.Outcome()) + } + if g.Method() != chess.Resignation { + t.Errorf("Method = %v, want Resignation", g.Method()) + } +} + +func TestMoveAfterGoBackFromTerminalStillRejected(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + if err := g.SetOutcomeMethod(chess.OutcomeMethodPair{chess.WhiteWon, chess.Checkmate}); err != nil { + t.Fatal(err) + } + if !g.MoveTree().GoBack() { + t.Fatal("GoBack failed") + } + if g.Outcome() != chess.WhiteWon { + t.Fatalf("outcome lost after GoBack: %s", g.Outcome()) + } + move := g.ValidMoves()[0] + _, err := g.Move(move, nil) + if !errors.Is(err, chess.ErrGameAlreadyEnded) { + t.Errorf("error = %v, want ErrGameAlreadyEnded", err) + } +} + +func TestAddVariationAllowedAfterTerminalOutcome(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + if err := g.SetOutcomeMethod(chess.OutcomeMethodPair{chess.WhiteWon, chess.Checkmate}); err != nil { + t.Fatal(err) + } + if !g.MoveTree().GoBack() { + t.Fatal("GoBack failed") + } + variation := g.ValidMoves()[0] + g.MoveTree().AddVariation(g.MoveTree().Root(), variation) + if len(g.MoveTree().Root().Children()) == 0 { + t.Error("AddVariation did not append child after terminal outcome") + } +} + +func TestClearOutcome(t *testing.T) { + g := chess.NewGame() + if err := g.SetOutcomeMethod(chess.OutcomeMethodPair{chess.WhiteWon, chess.Checkmate}); err != nil { + t.Fatal(err) + } + g.ClearOutcome() + if g.Outcome() != chess.NoOutcome { + t.Errorf("Outcome after Clear = %s, want NoOutcome", g.Outcome()) + } + if g.Method() != chess.NoMethod { + t.Errorf("Method after Clear = %s, want NoMethod", g.Method()) + } + g.ClearOutcome() + if g.Outcome() != chess.NoOutcome || g.Method() != chess.NoMethod { + t.Error("ClearOutcome should be idempotent") + } +} + +func TestClearOutcomeDoesNotModifyResultTag(t *testing.T) { + g := chess.NewGame() + g.AddTagPair("Result", "1-0") + if err := g.SetOutcomeMethod(chess.OutcomeMethodPair{chess.WhiteWon, chess.Checkmate}); err != nil { + t.Fatal(err) + } + g.ClearOutcome() + if got := g.GetTagPair("Result"); got != "1-0" { + t.Errorf("Result tag after ClearOutcome = %q, want 1-0", got) + } +} + +func TestTagPairLifecycle(t *testing.T) { + g := chess.NewGame() + if g.AddTagPair("Event", "E1") { + t.Error("first AddTagPair should return false (no prior value)") + } + if got := g.GetTagPair("Event"); got != "E1" { + t.Errorf("GetTagPair = %q, want E1", got) + } + if !g.AddTagPair("Event", "E2") { + t.Error("overwriting AddTagPair should return true") + } + if got := g.GetTagPair("Event"); got != "E2" { + t.Errorf("GetTagPair after overwrite = %q, want E2", got) + } + if !g.RemoveTagPair("Event") { + t.Error("RemoveTagPair on existing key should return true") + } + if got := g.GetTagPair("Event"); got != "" { + t.Errorf("GetTagPair after remove = %q, want empty", got) + } + if g.RemoveTagPair("Event") { + t.Error("RemoveTagPair on absent key should return false") + } + if g.RemoveTagPair("NeverExisted") { + t.Error("RemoveTagPair on never-existing key should return false") + } +} + +func TestEligibleDraws_FreshGameReturnsOnlyDrawOffer(t *testing.T) { + g := chess.NewGame() + draws := g.EligibleDraws() + if len(draws) != 1 || draws[0] != chess.DrawOffer { + t.Errorf("fresh game EligibleDraws = %v, want [DrawOffer]", draws) + } +} + +func TestEligibleDraws_IncludesThreefoldRepetitionWhenConditionsMet(t *testing.T) { + g := chess.NewGame() + for _, mv := range []string{"Nf3", "Nf6", "Ng1", "Ng8", "Nf3", "Nf6", "Ng1", "Ng8"} { + if _, err := g.MoveText(mv, chess.SAN(), nil); err != nil { + t.Fatal(err) + } + } + draws := g.EligibleDraws() + found := false + for _, d := range draws { + if d == chess.ThreefoldRepetition { + found = true + } + } + if !found { + t.Errorf("EligibleDraws = %v, want to include ThreefoldRepetition", draws) + } +} + +func TestDraw_RejectsInvalidMethod(t *testing.T) { + tests := []struct { + name string + method chess.Method + wantSub string + }{ + {"no_method", chess.NoMethod, "invalid draw method"}, + {"checkmate", chess.Checkmate, "invalid draw method"}, + {"resignation", chess.Resignation, "invalid draw method"}, + {"stalemate", chess.Stalemate, "invalid draw method"}, + {"fivefold_repetition", chess.FivefoldRepetition, "invalid draw method"}, + {"seventyfive_move_rule", chess.SeventyFiveMoveRule, "invalid draw method"}, + {"insufficient_material", chess.InsufficientMaterial, "invalid draw method"}, + {"threefold_repetition_unmet", chess.ThreefoldRepetition, "ThreefoldRepetition"}, + {"fifty_move_rule_unmet", chess.FiftyMoveRule, "FiftyMoveRule"}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + g := chess.NewGame() + err := g.Draw(tt.method) + if err == nil { + t.Fatalf("Draw(%s) = nil, want error", tt.method) + } + if !strings.Contains(err.Error(), tt.wantSub) { + t.Errorf("Draw(%s) error = %q, want substring %q", tt.method, err.Error(), tt.wantSub) + } + if g.Outcome() != chess.NoOutcome { + t.Errorf("Outcome = %v after rejected Draw, want NoOutcome", g.Outcome()) + } + }) + } +} + +func TestDrawOfferSucceeds(t *testing.T) { + g := chess.NewGame() + if err := g.Draw(chess.DrawOffer); err != nil { + t.Fatalf("Draw(DrawOffer) = %v, want nil", err) + } + if g.Outcome() != chess.Draw { + t.Errorf("Outcome = %v, want Draw", g.Outcome()) + } + if g.Method() != chess.DrawOffer { + t.Errorf("Method = %v, want DrawOffer", g.Method()) + } +} diff --git a/game_split.go b/game_split.go new file mode 100644 index 00000000..4354448b --- /dev/null +++ b/game_split.go @@ -0,0 +1,68 @@ +package chess + +// Split takes a Game with a main line and 0 or more variations and returns a +// slice of Games (one for each variation), each containing exactly only a main +// line and 0 variations. +func (g *Game) Split() []*Game { + // Build a Game for each path + var games []*Game + for _, path := range g.tree.Lines() { + newG := g.buildOneGameFromPath(path) + games = append(games, newG) + } + + return games +} + +func (g *Game) buildOneGameFromPath(path []*MoveNode) *Game { + rootPos := g.tree.rootPos.copy() + rootMove := &MoveNode{} + cur := rootMove + + for _, m := range path { + child := &MoveNode{ + move: m.move, + number: m.number, + nags: append([]string(nil), m.nags...), + commentBlocks: copyCommentBlocks(m.commentBlocks), + } + child.parent = cur + + cur.children = []*MoveNode{child} + cur = child + } + + newG := &Game{} + newG.copy(g) + // Build a fresh single-line tree; copy() skips tree. Seed rootPos from + // the path's starting position and let setCurrent replay the move chain + // so pos / undos / current are all consistent with the leaf cursor. + // current is left on root so setCurrent's "node == current" early-return + // does not skip the replay. + newG.tree = &MoveTree{ + root: rootMove, + current: rootMove, + rootPos: rootPos, + pos: rootPos.copy(), + } + newG.tree.setTree(rootMove) + newG.tree.setCurrent(cur) + + // Discard any manual outcome inherited from the parent game and recompute + // from the leaf using the Full policy (all automatic draws, honouring the + // ignore flags). Split is the only path that syncs the Result tag, because + // each split game is built from scratch and must carry a self-consistent + // tag for PGN serialization. + newG.outcome, newG.method = classifyOutcome(newG.currentPosition(), newG.numOfRepetitions(), fullOutcomeRules(newG)) + newG.syncResultTag() + + return newG +} + +func (g *Game) syncResultTag() { + if g.outcome == NoOutcome { + delete(g.tagPairs, "Result") + return + } + g.tagPairs["Result"] = g.outcome.String() +} diff --git a/game_split_recompute_test.go b/game_split_recompute_test.go new file mode 100644 index 00000000..302974b4 --- /dev/null +++ b/game_split_recompute_test.go @@ -0,0 +1,227 @@ +package chess_test + +import ( + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +func assertNoVariations(t *testing.T, g *chess.Game) { + t.Helper() + var walk func(node *chess.MoveNode) + walk = func(node *chess.MoveNode) { + if children := node.Children(); len(children) > 1 { + t.Errorf("node has %d children, split games must have 0 variations", len(children)) + } + for _, c := range node.Children() { + walk(c) + } + } + walk(g.MoveTree().Root()) +} + +func TestSplit_DropsManualResignationOnDivergingLine(t *testing.T) { + g := chess.NewGame() + for _, m := range []string{"e4", "e5", "Nf3", "Nc6"} { + if _, err := g.MoveText(m, chess.SAN(), nil); err != nil { + t.Fatalf("push %s: %v", m, err) + } + } + if !g.MoveTree().GoBack() { + t.Fatal("GoBack failed") + } + if _, err := g.MoveText("d6", chess.SAN(), nil); err != nil { + t.Fatalf("push d6: %v", err) + } + if _, err := g.MoveText("d4", chess.SAN(), nil); err != nil { + t.Fatalf("push d4: %v", err) + } + if err := g.Resign(chess.White); err != nil { + t.Fatalf("Resign: %v", err) + } + + if g.Outcome() != chess.BlackWon || g.Method() != chess.Resignation { + t.Fatalf("parent outcome/method = %s/%s, want BlackWon/Resignation", g.Outcome(), g.Method()) + } + + splitGames := g.Split() + if len(splitGames) != 2 { + t.Fatalf("split game count = %d, want 2", len(splitGames)) + } + + for i, sg := range splitGames { + if sg.Outcome() != chess.NoOutcome { + t.Errorf("split[%d] outcome = %s, want NoOutcome (resignation is not recomputed)", i, sg.Outcome()) + } + if sg.Method() != chess.NoMethod { + t.Errorf("split[%d] method = %s, want NoMethod", i, sg.Method()) + } + assertNoVariations(t, sg) + } +} + +func TestSplit_RecomputesTerminalOutcomesFromLeaf(t *testing.T) { + tests := []struct { + name string + pgn string + wantOutcome chess.Outcome + wantMethod chess.Method + wantResult string + }{ + { + name: "checkmate", + pgn: "1. e4 e5 2. Bc4 Nc6 3. Qh5 Nf6?? 4. Qxf7# 1-0", + wantOutcome: chess.WhiteWon, + wantMethod: chess.Checkmate, + wantResult: "1-0", + }, + { + name: "stalemate", + pgn: `[Event "E"] +[Site "S"] +[Date "2026.06.19"] +[Round "1"] +[White "A"] +[Black "B"] +[Result "1/2-1/2"] + +1. e3 a5 2. Qh5 Ra6 3. Qxa5 h5 4. h4 Rah6 5. Qxc7 f6 6. Qxd7+ Kf7 7. Qxb7 Qd3 8. Qxb8 Qh7 9. Qxc8 Kg6 10. Qe6 1/2-1/2`, + wantOutcome: chess.Draw, + wantMethod: chess.Stalemate, + wantResult: "1/2-1/2", + }, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + g, err := chess.ParsePGN(strings.NewReader(tt.pgn)) + if err != nil { + t.Fatal(err) + } + + splitGames := g.Split() + if len(splitGames) == 0 { + t.Fatal("expected at least one split game") + } + + found := false + for _, sg := range splitGames { + if sg.Outcome() == tt.wantOutcome && sg.Method() == tt.wantMethod { + found = true + if got := sg.GetTagPair("Result"); got != tt.wantResult { + t.Errorf("Result tag = %q, want %q (Split must sync the Result tag)", got, tt.wantResult) + } + } + assertNoVariations(t, sg) + } + if !found { + t.Errorf("no split line recomputed to %s/%s", tt.wantOutcome, tt.wantMethod) + } + }) + } +} + +// TestSplit_HonoursIgnoreFlags pins the recomputeOutcomeFromLeaf bug fix: +// Split previously checked insufficient material without consulting the +// Game's ignore flag, so a parent game kept in progress by +// IgnoreInsufficientMaterialDraw was wrongly drawn after Split. +func TestSplit_HonoursIgnoreFlags(t *testing.T) { + fenOpt, err := chess.FEN("4k3/8/8/8/8/8/8/3K4 w - - 0 60") // KvK: insufficient material + if err != nil { + t.Fatal(err) + } + // The ignore option must precede FEN: FEN evaluates status while applied, + // so the flag has to be set first for the parent to stay in progress. + g := chess.NewGame(chess.IgnoreInsufficientMaterialDraw(), fenOpt) + if g.Outcome() != chess.NoOutcome { + t.Fatalf("parent outcome = %s, want NoOutcome (ignore flag honoured at FEN)", g.Outcome()) + } + // Split yields a game per line; push a quiet king move (position stays KvK + // insufficient) so there is a line to split. + if _, err := g.MoveText("Kd2", chess.SAN(), nil); err != nil { + t.Fatalf("push Kd2: %v", err) + } + if g.Outcome() != chess.NoOutcome { + t.Fatalf("parent outcome after move = %s, want NoOutcome", g.Outcome()) + } + + splitGames := g.Split() + if len(splitGames) != 1 { + t.Fatalf("split game count = %d, want 1", len(splitGames)) + } + sg := splitGames[0] + if sg.Outcome() != chess.NoOutcome || sg.Method() != chess.NoMethod { + t.Errorf("split outcome/method = %s/%s, want NoOutcome/NoMethod (ignore flag must carry through Split)", + sg.Outcome(), sg.Method()) + } + assertNoVariations(t, sg) +} + +// TestSplit_EmitsAutoDraws pins the observable change: Split now derives +// automatic draws (fivefold, seventy-five move rule) from the rebuilt main +// line. The deleted recomputeOutcomeFromLeaf only handled mate/stalemate and +// insufficient material, so these positions previously stayed NoOutcome. +func TestSplit_EmitsAutoDraws(t *testing.T) { + t.Run("seventy-five move rule", func(t *testing.T) { + // Start one half-move below the threshold with sufficient material + // (rook), then push a quiet rook move to reach clock 150. + fenOpt, err := chess.FEN("4k3/8/8/8/8/8/8/R3K3 w - - 149 60") + if err != nil { + t.Fatal(err) + } + g := chess.NewGame(fenOpt) + if g.Outcome() != chess.NoOutcome { + t.Fatalf("parent outcome at clock 149 = %s, want NoOutcome", g.Outcome()) + } + if _, err := g.MoveText("Ra2", chess.SAN(), nil); err != nil { + t.Fatalf("push Ra2: %v", err) + } + if g.Outcome() != chess.Draw || g.Method() != chess.SeventyFiveMoveRule { + t.Fatalf("parent outcome/method = %s/%s, want Draw/SeventyFiveMoveRule", g.Outcome(), g.Method()) + } + + splitGames := g.Split() + if len(splitGames) != 1 { + t.Fatalf("split game count = %d, want 1", len(splitGames)) + } + sg := splitGames[0] + if sg.Outcome() != chess.Draw || sg.Method() != chess.SeventyFiveMoveRule { + t.Errorf("split outcome/method = %s/%s, want Draw/SeventyFiveMoveRule", sg.Outcome(), sg.Method()) + } + if got := sg.GetTagPair("Result"); got != "1/2-1/2" { + t.Errorf("Result tag = %q, want \"1/2-1/2\" (Split must sync the tag)", got) + } + assertNoVariations(t, sg) + }) + + t.Run("fivefold repetition", func(t *testing.T) { + // Shuffle both knights out and back four times: the position returns + // to the start after each 4-ply cycle, giving five occurrences and an + // automatic fivefold-repetition draw. + g := chess.NewGame() + cycle := []string{"Nf3", "Nf6", "Ng1", "Ng8"} + for range 4 { + for _, m := range cycle { + if _, err := g.MoveText(m, chess.SAN(), nil); err != nil { + t.Fatalf("push %s: %v", m, err) + } + } + } + if g.Outcome() != chess.Draw || g.Method() != chess.FivefoldRepetition { + t.Fatalf("parent outcome/method = %s/%s, want Draw/FivefoldRepetition", g.Outcome(), g.Method()) + } + + splitGames := g.Split() + if len(splitGames) != 1 { + t.Fatalf("split game count = %d, want 1", len(splitGames)) + } + sg := splitGames[0] + if sg.Outcome() != chess.Draw || sg.Method() != chess.FivefoldRepetition { + t.Errorf("split outcome/method = %s/%s, want Draw/FivefoldRepetition", sg.Outcome(), sg.Method()) + } + if got := sg.GetTagPair("Result"); got != "1/2-1/2" { + t.Errorf("Result tag = %q, want \"1/2-1/2\" (Split must sync the tag)", got) + } + assertNoVariations(t, sg) + }) +} diff --git a/game_test.go b/game_test.go index 1fe3b9a0..9b44927a 100644 --- a/game_test.go +++ b/game_test.go @@ -8,6 +8,32 @@ import ( "time" ) +func TestGameAccessorsReturnDefensiveCopies(t *testing.T) { + game := NewGame() + if _, err := game.MoveText("e4", SAN(), nil); err != nil { + t.Fatal(err) + } + game.MoveTree().AddVariation(nil, Move{s1: D2, s2: D4}) + + children := game.MoveTree().Root().Children() + children[0] = nil + if game.MoveTree().Root().children[0] == nil { + t.Fatal("Children returned mutable backing slice") + } + + variations := game.MoveTree().Variations(game.MoveTree().Root()) + variations[0] = nil + if game.MoveTree().Root().children[1] == nil { + t.Fatal("Variations returned mutable backing slice") + } + + pos := game.Position() + pos.board.mailbox[E4] = NoPiece + if got := game.Position().Board().Piece(E4); got != WhitePawn { + t.Fatalf("Position returned mutable game position, E4 = %v, want %v", got, WhitePawn) + } +} + func TestCheckmate(t *testing.T) { fenStr := "rn1qkbnr/pbpp1ppp/1p6/4p3/2B1P3/5Q2/PPPP1PPP/RNB1K1NR w KQkq - 0 1" fen, err := FEN(fenStr) @@ -15,7 +41,7 @@ func TestCheckmate(t *testing.T) { t.Fatal(err) } g := NewGame(fen) - if err := g.PushMove("Qxf7#", nil); err != nil { + if _, err := g.MoveText("Qxf7#", SAN(), nil); err != nil { t.Fatal(err) } if g.Method() != Checkmate { @@ -32,7 +58,7 @@ func TestCheckmate(t *testing.T) { t.Fatal(err) } g = NewGame(fen) - if err := g.PushMove("O-O-O", nil); err != nil { + if _, err := g.MoveText("O-O-O", SAN(), nil); err != nil { t.Fatal(err) } t.Log(g.Position().String()) @@ -67,7 +93,7 @@ func TestStalemate(t *testing.T) { t.Fatal(err) } g := NewGame(fen) - if err := g.PushMove("Qb6", nil); err != nil { + if _, err := g.MoveText("Qb6", SAN(), nil); err != nil { t.Fatal(err) } if g.Method() != Stalemate { @@ -86,7 +112,7 @@ func TestInvalidStalemate(t *testing.T) { t.Fatal(err) } g := NewGame(fen) - if err := g.PushMove("d8=Q", nil); err != nil { + if _, err := g.MoveText("d8=Q", SAN(), nil); err != nil { t.Fatal(err) } if g.Outcome() != NoOutcome { @@ -101,7 +127,7 @@ func TestThreeFoldRepetition(t *testing.T) { "Nf3", "Nf6", "Ng1", "Ng8", } for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } @@ -120,7 +146,7 @@ func TestInvalidThreeFoldRepetition(t *testing.T) { "Nf3", "Nf6", "Ng1", "Ng8", } for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } @@ -138,7 +164,7 @@ func TestFiveFoldRepetition(t *testing.T) { "Nf3", "Nf6", "Ng1", "Ng8", } for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } @@ -156,7 +182,7 @@ func TestFiveFoldRepetitionIgnored(t *testing.T) { "Nf3", "Nf6", "Ng1", "Ng8", } for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } @@ -184,7 +210,7 @@ func TestInvalidFiftyMoveRule(t *testing.T) { func TestSeventyFiveMoveRule(t *testing.T) { fen, _ := FEN("2r3k1/1q1nbppp/r3p3/3pP3/pPpP4/P1Q2N2/2RN1PPP/2R4K b - b3 149 80") g := NewGame(fen) - if err := g.PushMove("Kf8", nil); err != nil { + if _, err := g.MoveText("Kf8", SAN(), nil); err != nil { t.Fatal(err) } if g.Outcome() != Draw || g.Method() != SeventyFiveMoveRule { @@ -195,7 +221,7 @@ func TestSeventyFiveMoveRule(t *testing.T) { func TestSeventyFiveMoveRuleIgnored(t *testing.T) { fen, _ := FEN("2r3k1/1q1nbppp/r3p3/3pP3/pPpP4/P1Q2N2/2RN1PPP/2R4K b - b3 149 80") g := NewGame(fen, IgnoreSeventyFiveMoveRuleDraw()) - if err := g.PushMove("Kf8", nil); err != nil { + if _, err := g.MoveText("Kf8", SAN(), nil); err != nil { t.Fatal(err) } if g.Outcome() == Draw && g.Method() == SeventyFiveMoveRule { @@ -277,11 +303,11 @@ func TestInitialNumOfValidMoves(t *testing.T) { func TestPositionHash(t *testing.T) { g1 := NewGame() for _, s := range []string{"Nc3", "e5", "Nf3"} { - g1.PushMove(s, nil) + g1.MoveText(s, SAN(), nil) } g2 := NewGame() for _, s := range []string{"Nf3", "e5", "Nc3"} { - g2.PushMove(s, nil) + g2.MoveText(s, SAN(), nil) } if g1.Position().ZobristHash() != g2.Position().ZobristHash() { t.Fatalf("expected position hashes to be equal but got %x and %x", g1.Position().ZobristHash(), g2.Position().ZobristHash()) @@ -295,11 +321,11 @@ func BenchmarkStalemateStatus(b *testing.B) { b.Fatal(err) } g := NewGame(fen) - if err := g.PushMove("Qb6", nil); err != nil { + if _, err := g.MoveText("Qb6", SAN(), nil); err != nil { b.Fatal(err) } b.ResetTimer() - for n := 0; n < b.N; n++ { + for range b.N { g.Position().Status() } } @@ -311,11 +337,11 @@ func BenchmarkInvalidStalemateStatus(b *testing.B) { b.Fatal(err) } g := NewGame(fen) - if err := g.PushMove("d8=Q", nil); err != nil { + if _, err := g.MoveText("d8=Q", SAN(), nil); err != nil { b.Fatal(err) } b.ResetTimer() - for n := 0; n < b.N; n++ { + for range b.N { g.Position().Status() } } @@ -328,83 +354,101 @@ func BenchmarkPositionHash(b *testing.B) { } g := NewGame(fen) b.ResetTimer() - for n := 0; n < b.N; n++ { + for range b.N { g.Position().ZobristHash() } } func TestAddVariationToEmptyParent(t *testing.T) { g := NewGame() - parent := &Move{} - newMove := &Move{} - g.AddVariation(parent, newMove) - if len(parent.children) != 1 || parent.children[0] != newMove { + parent := g.MoveTree().Root() + newMove := Move{s1: E2, s2: E4} + node, err := g.MoveTree().AddVariation(parent, newMove) + if err != nil { + t.Fatal(err) + } + if len(parent.children) != 1 || parent.children[0] != node || parent.children[0].move != newMove { t.Fatalf("expected newMove to be added to parent's children") } - if newMove.parent != parent { + if parent.children[0].parent != parent { t.Fatalf("expected newMove's parent to be set to parent") } } func TestAddVariationToNonEmptyParent(t *testing.T) { g := NewGame() - parent := &Move{children: []*Move{{}}} - newMove := &Move{} - g.AddVariation(parent, newMove) - if len(parent.children) != 2 || parent.children[1] != newMove { + parent := g.MoveTree().Root() + if _, err := g.MoveTree().AddVariation(parent, Move{s1: E2, s2: E4}); err != nil { + t.Fatal(err) + } + newMove := Move{s1: D2, s2: D4} + node, err := g.MoveTree().AddVariation(parent, newMove) + if err != nil { + t.Fatal(err) + } + if len(parent.children) != 2 || parent.children[1] != node || parent.children[1].move != newMove { t.Fatalf("expected newMove to be added to parent's children") } - if newMove.parent != parent { + if parent.children[1].parent != parent { t.Fatalf("expected newMove's parent to be set to parent") } } func TestAddVariationWithNilParent(t *testing.T) { g := NewGame() - newMove := &Move{} - defer func() { - if r := recover(); r == nil { - t.Fatalf("expected panic when parent is nil") - } - }() - g.AddVariation(nil, newMove) + newMove := Move{s1: E2, s2: E4} + if _, err := g.MoveTree().AddVariation(nil, newMove); err != nil { + t.Fatal(err) + } + if len(g.MoveTree().Root().children) != 1 { + t.Fatalf("expected variation attached to root, got %d children", len(g.MoveTree().Root().children)) + } + if g.MoveTree().Root().children[0].move != newMove { + t.Fatalf("expected variation move %v, got %v", newMove, g.MoveTree().Root().children[0].move) + } + if g.MoveTree().Root().children[0].parent != g.MoveTree().Root() { + t.Fatal("expected variation parent pointer to be the root move") + } } func TestNavigateToMainLineFromLeaf(t *testing.T) { g := NewGame() moves := []string{"e4", "e5", "Nf3", "Nc6", "Bb5"} for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } - g.NavigateToMainLine() - if g.currentMove != g.rootMove.children[0] { + g.MoveTree().NavigateToMainLine() + if g.MoveTree().Current() != g.MoveTree().Root().children[0] { t.Fatalf("expected to navigate to main line root move") } } -func TestNavigateToMainLineFromBranch(t *testing.T) { +func TestNavigateToMainLineFromVariation(t *testing.T) { g := NewGame() moves := []string{"e4", "e5", "Nf3", "Nc6", "Bb5"} for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } - variationMove := &Move{} - g.AddVariation(g.currentMove, variationMove) - g.currentMove = variationMove - g.NavigateToMainLine() - if g.currentMove != g.rootMove.children[0] { + variationMove := Move{s1: A7, s2: A6} + variationNode, err := g.MoveTree().AddVariation(g.MoveTree().Current(), variationMove) + if err != nil { + t.Fatal(err) + } + g.tree.setCurrent(variationNode) + g.MoveTree().NavigateToMainLine() + if g.MoveTree().Current() != g.MoveTree().Root().children[0] { t.Fatalf("expected to navigate to main line root move") } } func TestNavigateToMainLineFromRoot(t *testing.T) { g := NewGame() - g.NavigateToMainLine() - if g.currentMove != g.rootMove { + g.MoveTree().NavigateToMainLine() + if g.MoveTree().Current() != g.MoveTree().Root() { t.Fatalf("expected to stay at root move") } } @@ -413,24 +457,24 @@ func TestGoBackFromLeaf(t *testing.T) { g := NewGame() moves := []string{"e4", "e5", "Nf3", "Nc6", "Bb5"} for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } - if !g.GoBack() { + if !g.MoveTree().GoBack() { t.Fatalf("expected to go back from leaf move") } - if g.currentMove != g.rootMove.children[0].children[0].children[0].children[0] { + if g.MoveTree().Current() != g.MoveTree().Root().children[0].children[0].children[0].children[0] { t.Fatalf("expected current move to be Bb5's parent") } } func TestGoBackFromRoot(t *testing.T) { g := NewGame() - if g.GoBack() { + if g.MoveTree().GoBack() { t.Fatalf("expected not to go back from root move") } - if g.currentMove != g.rootMove { + if g.MoveTree().Current() != g.MoveTree().Root() { t.Fatalf("expected to stay at root move") } } @@ -439,27 +483,27 @@ func TestGoBackFromMainLine(t *testing.T) { g := NewGame() moves := []string{"e4", "e5", "Nf3"} for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } - if !g.GoBack() { + if !g.MoveTree().GoBack() { t.Fatalf("expected to go back from main line move") } - if g.currentMove != g.rootMove.children[0].children[0] { + if g.MoveTree().Current() != g.MoveTree().Root().children[0].children[0] { t.Fatalf("expected current move to be e5's parent") } } func TestGoForwardFromRoot(t *testing.T) { g := NewGame() - _ = g.PushMove("e4", nil) - _ = g.PushMove("e5", nil) - g.currentMove = g.rootMove // Reset to root - if !g.GoForward() { + _, _ = g.MoveText("e4", SAN(), nil) + _, _ = g.MoveText("e5", SAN(), nil) + g.tree.setCurrent(g.MoveTree().Root()) // Reset to root + if !g.MoveTree().GoForward() { t.Fatalf("expected to go forward from root move") } - if g.currentMove != g.rootMove.children[0] { + if g.MoveTree().Current() != g.MoveTree().Root().children[0] { t.Fatalf("expected current move to be the first child of root move") } } @@ -468,35 +512,40 @@ func TestGoForwardFromLeaf(t *testing.T) { g := NewGame() moves := []string{"e4", "e5", "Nf3", "Nc6", "Bb5"} for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } - if g.GoForward() { + if g.MoveTree().GoForward() { t.Fatalf("expected not to go forward from leaf move") } - if g.currentMove != g.rootMove.children[0].children[0].children[0].children[0].children[0] { + if g.MoveTree().Current() != g.MoveTree().Root().children[0].children[0].children[0].children[0].children[0] { t.Fatalf("expected current move to stay at leaf move") } } -func TestGoForwardFromBranch(t *testing.T) { +func TestGoForwardFromVariation(t *testing.T) { g := NewGame() moves := []string{"e4", "e5", "Nf3", "Nc6"} for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } - variationMove := &Move{} - g.AddVariation(g.currentMove, variationMove) - childMove := &Move{} // Add this line - g.AddVariation(variationMove, childMove) // Add this line - g.currentMove = variationMove - if !g.GoForward() { - t.Fatalf("expected to go forward from branch move") + variationMove := Move{s1: F1, s2: B5} + variationNode, err := g.MoveTree().AddVariation(g.MoveTree().Current(), variationMove) + if err != nil { + t.Fatal(err) + } + childMove := Move{s1: A7, s2: A6} + if _, err := g.MoveTree().AddVariation(variationNode, childMove); err != nil { + t.Fatal(err) } - if g.currentMove != childMove { // Change this line + g.tree.setCurrent(variationNode) + if !g.MoveTree().GoForward() { + t.Fatalf("expected to go forward from variation move") + } + if g.MoveTree().Current().move != childMove { t.Fatalf("expected current move to be the child of the variation move") } } @@ -510,7 +559,7 @@ func TestIsAtStartWhenAtRoot(t *testing.T) { func TestIsAtStartWhenNotAtRoot(t *testing.T) { g := NewGame() - if err := g.PushMove("e4", nil); err != nil { + if _, err := g.MoveText("e4", SAN(), nil); err != nil { t.Fatal(err) } if g.IsAtStart() { @@ -520,7 +569,7 @@ func TestIsAtStartWhenNotAtRoot(t *testing.T) { func TestIsAtEndWhenAtLeaf(t *testing.T) { g := NewGame() - if err := g.PushMove("e4", nil); err != nil { + if _, err := g.MoveText("e4", SAN(), nil); err != nil { t.Fatal(err) } if !g.IsAtEnd() { @@ -530,14 +579,14 @@ func TestIsAtEndWhenAtLeaf(t *testing.T) { func TestIsAtEndWhenNotAtLeaf(t *testing.T) { g := NewGame() - if err := g.PushMove("e4", nil); err != nil { + if _, err := g.MoveText("e4", SAN(), nil); err != nil { t.Fatal(err) } - if err := g.PushMove("e5", nil); err != nil { + if _, err := g.MoveText("e5", SAN(), nil); err != nil { t.Fatal(err) } // Add this line to move back to a non-leaf position - g.GoBack() + g.MoveTree().GoBack() if g.IsAtEnd() { t.Fatalf("expected not to be at end when not at leaf move") } @@ -545,8 +594,8 @@ func TestIsAtEndWhenNotAtLeaf(t *testing.T) { func TestVariationsWithNoChildren(t *testing.T) { g := NewGame() - move := &Move{} - variations := g.Variations(move) + move := &MoveNode{} + variations := g.MoveTree().Variations(move) if variations != nil { t.Fatalf("expected no variations for move with no children") } @@ -554,8 +603,8 @@ func TestVariationsWithNoChildren(t *testing.T) { func TestVariationsWithOneChild(t *testing.T) { g := NewGame() - move := &Move{children: []*Move{{}}} - variations := g.Variations(move) + move := &MoveNode{children: []*MoveNode{{}}} + variations := g.MoveTree().Variations(move) if variations != nil { t.Fatalf("expected no variations for move with one child") } @@ -563,8 +612,8 @@ func TestVariationsWithOneChild(t *testing.T) { func TestVariationsWithMultipleChildren(t *testing.T) { g := NewGame() - move := &Move{children: []*Move{{}, {}}} - variations := g.Variations(move) + move := &MoveNode{children: []*MoveNode{{}, {}}} + variations := g.MoveTree().Variations(move) if len(variations) != 1 { t.Fatalf("expected one variation for move with multiple children") } @@ -572,57 +621,22 @@ func TestVariationsWithMultipleChildren(t *testing.T) { func TestVariationsWithNilMove(t *testing.T) { g := NewGame() - variations := g.Variations(nil) + variations := g.MoveTree().Variations(nil) if variations != nil { t.Fatalf("expected no variations for nil move") } } -func TestCommentsWithNoComments(t *testing.T) { - g := NewGame() - comments := g.Comments() - if len(comments) != 0 { - t.Fatalf("expected no comments but got %d", len(comments)) - } -} - -func TestCommentsWithSingleComment(t *testing.T) { - g := NewGame() - g.comments = [][]string{{"First comment"}} - comments := g.Comments() - if len(comments) != 1 || comments[0][0] != "First comment" { - t.Fatalf("expected one comment 'First comment' but got %v", comments) - } -} - -func TestCommentsWithMultipleComments(t *testing.T) { - g := NewGame() - g.comments = [][]string{{"First comment"}, {"Second comment"}} - comments := g.Comments() - if len(comments) != 2 || comments[0][0] != "First comment" || comments[1][0] != "Second comment" { - t.Fatalf("expected comments 'First comment' and 'Second comment' but got %v", comments) - } -} - -func TestCommentsWithNilComments(t *testing.T) { - g := NewGame() - g.comments = nil - comments := g.Comments() - if comments == nil || len(comments) != 0 { - t.Fatalf("expected no comments but got %v", comments) - } -} - func TestPushMove(t *testing.T) { tests := []struct { name string - setupMoves []string // Moves to set up the position - move string // Move to push - goBack bool // Whether to go back one move before pushing - options *PushMoveOptions // Options for the push - wantErr bool // Whether we expect an error - wantPosition string // Expected FEN after the move - checkMainline []string // Expected mainline moves in UCI notation + setupMoves []string // Moves to set up the position + move string // Move to push + goBack bool // Whether to go back one move before pushing + options *MoveInsertOptions // Options for the push + wantErr bool // Whether we expect an error + wantPosition string // Expected FEN after the move + checkMainline []string // Expected mainline moves in UCI notation }{ { name: "basic pawn move", @@ -648,7 +662,7 @@ func TestPushMove(t *testing.T) { setupMoves: []string{"e4", "e5", "Nf3"}, move: "Nc3", goBack: true, - options: &PushMoveOptions{}, + options: &MoveInsertOptions{}, wantPosition: "rnbqkbnr/pppp1ppp/8/4p3/4P3/2N5/PPPP1PPP/R1BQKBNR b KQkq - 1 2", checkMainline: []string{"e2e4", "e7e5", "g1f3"}, // Original mainline remains }, @@ -657,7 +671,7 @@ func TestPushMove(t *testing.T) { setupMoves: []string{"e4", "e5", "Nf3"}, move: "Nc3", goBack: true, - options: &PushMoveOptions{ForceMainline: true}, + options: &MoveInsertOptions{PromoteToMainLine: true}, wantPosition: "rnbqkbnr/pppp1ppp/8/4p3/4P3/2N5/PPPP1PPP/R1BQKBNR b KQkq - 1 2", checkMainline: []string{"e2e4", "e7e5", "b1c3"}, // New mainline }, @@ -666,7 +680,7 @@ func TestPushMove(t *testing.T) { setupMoves: []string{"e4", "e5", "Nf3"}, move: "Nf3", goBack: true, - options: &PushMoveOptions{}, + options: &MoveInsertOptions{}, wantPosition: "rnbqkbnr/pppp1ppp/8/4p3/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2", checkMainline: []string{"e2e4", "e7e5", "g1f3"}, }, @@ -700,19 +714,19 @@ func TestPushMove(t *testing.T) { // Setup moves for _, move := range tt.setupMoves { - err := game.PushMove(move, nil) + _, err := game.MoveText(move, SAN(), nil) if err != nil { t.Fatalf("setup failed: %v", err) } } // Go back one move if needed for the test - if tt.goBack && game.currentMove != nil && game.currentMove.parent != nil { - game.GoBack() + if tt.goBack && game.MoveTree().Current() != nil && game.MoveTree().Current().parent != nil { + game.MoveTree().GoBack() } // Test the move - err := game.PushMove(tt.move, tt.options) + _, err := game.MoveText(tt.move, SAN(), tt.options) // Check error expectation if (err != nil) != tt.wantErr { @@ -726,7 +740,7 @@ func TestPushMove(t *testing.T) { // Check position if tt.wantPosition != "" { - gotFEN := game.pos.String() + gotFEN := game.currentPosition().String() if gotFEN != tt.wantPosition { t.Errorf("Position after move = %v, want %v", gotFEN, tt.wantPosition) } @@ -746,7 +760,7 @@ func TestPushMove(t *testing.T) { // Helper function to get the mainline moves from a game func getMainline(game *Game) []string { var moves []string - current := game.rootMove + current := game.MoveTree().Root() for len(current.children) > 0 { current = current.children[0] // Follow main line (first variation) @@ -757,20 +771,21 @@ func getMainline(game *Game) []string { } // Helper function to convert a move to algebraic notation -func algebraicMove(move *Move) string { +func algebraicMove(move *MoveNode) string { + mv := move.Move() // This is a simplified version - you might want to implement proper algebraic notation - if move.HasTag(KingSideCastle) { + if mv.HasTag(KingSideCastle) { return "O-O" } - if move.HasTag(QueenSideCastle) { + if mv.HasTag(QueenSideCastle) { return "O-O-O" } - s1 := move.s1.String() - s2 := move.s2.String() + s1 := mv.s1.String() + s2 := mv.s2.String() - if move.promo != NoPieceType { - return s1 + s2 + "=" + move.promo.String() + if mv.promo != NoPieceType { + return s1 + s2 + "=" + mv.promo.String() } return s1 + s2 @@ -791,18 +806,19 @@ func moveSlicesEqual(a, b []string) bool { func TestCopyGameState(t *testing.T) { original := NewGame() - _ = original.PushMove("e4", nil) - _ = original.PushMove("e5", nil) - _ = original.PushMove("Nf3", nil) + _, _ = original.MoveText("e4", SAN(), nil) + _, _ = original.MoveText("e5", SAN(), nil) + _, _ = original.MoveText("Nf3", SAN(), nil) newGame := NewGame() newGame.copy(original) + newGame.tree = original.tree // copy() does not set tree; caller hands it over - if newGame.pos.String() != original.pos.String() { - t.Fatalf("expected position %s but got %s", original.pos.String(), newGame.pos.String()) + if newGame.currentPosition().String() != original.currentPosition().String() { + t.Fatalf("expected position %s but got %s", original.currentPosition().String(), newGame.currentPosition().String()) } - if newGame.currentMove != original.currentMove { - t.Fatalf("expected current move to be %v but got %v", original.currentMove, newGame.currentMove) + if newGame.MoveTree().Current() != original.MoveTree().Current() { + t.Fatalf("expected current move to be %v but got %v", original.MoveTree().Current(), newGame.MoveTree().Current()) } if newGame.outcome != original.outcome { t.Fatalf("expected outcome %s but got %s", original.outcome, newGame.outcome) @@ -810,21 +826,6 @@ func TestCopyGameState(t *testing.T) { if newGame.method != original.method { t.Fatalf("expected method %d but got %d", original.method, newGame.method) } - if len(newGame.Comments()) != len(original.Comments()) { - t.Fatalf("expected comments %v but got %v", original.Comments(), newGame.Comments()) - } -} - -func TestCopyGameStateWithNilComments(t *testing.T) { - original := NewGame() - original.comments = nil - - newGame := NewGame() - newGame.copy(original) - - if newGame.comments == nil { - t.Fatalf("expected comments to be initialized") - } } func TestCopyGameStateWithTagPairs(t *testing.T) { @@ -841,22 +842,22 @@ func TestCopyGameStateWithTagPairs(t *testing.T) { func TestCloneGameState(t *testing.T) { original := NewGame() - _ = original.PushMove("e4", nil) - _ = original.PushMove("e5", nil) - _ = original.PushMove("Nf3", nil) + _, _ = original.MoveText("e4", SAN(), nil) + _, _ = original.MoveText("e5", SAN(), nil) + _, _ = original.MoveText("Nf3", SAN(), nil) clone := original.Clone() - if clone.pos.String() != original.pos.String() { - t.Fatalf("expected position %s but got %s", original.pos.String(), clone.pos.String()) + if clone.currentPosition().String() != original.currentPosition().String() { + t.Fatalf("expected position %s but got %s", original.currentPosition().String(), clone.currentPosition().String()) } - if clone.currentMove.String() != original.currentMove.String() { - t.Fatalf("expected current move to be %v but got %v", original.currentMove, clone.currentMove) + if clone.MoveTree().Current().Move().String() != original.MoveTree().Current().Move().String() { + t.Fatalf("expected current move to be %v but got %v", original.MoveTree().Current(), clone.MoveTree().Current()) } - if clone.currentMove == original.currentMove { + if clone.MoveTree().Current() == original.MoveTree().Current() { t.Errorf("clone failed to deep copy currentMove") } - if clone.rootMove == original.rootMove { + if clone.MoveTree().Root() == original.MoveTree().Root() { t.Errorf("clone failed to deep copy rootMove") } if clone.outcome != original.outcome { @@ -865,16 +866,13 @@ func TestCloneGameState(t *testing.T) { if clone.method != original.method { t.Fatalf("expected method %d but got %d", original.method, clone.method) } - if len(clone.Comments()) != len(original.Comments()) { - t.Fatalf("expected comments %v but got %v", original.Comments(), clone.Comments()) - } // make sure we can modify the clone without impact on the original - err := clone.PushMove("Nf6", nil) + _, err := clone.MoveText("Nf6", SAN(), nil) if err != nil { t.Fatalf("failed to push Nf6") } - if clone.pos.String() == original.pos.String() { + if clone.currentPosition().String() == original.currentPosition().String() { t.Error("modifying the clone incorrectly mutates the original position") } if len(clone.Moves()) == len(original.Moves()) { @@ -885,14 +883,15 @@ func TestCloneGameState(t *testing.T) { } } -func TestCloneGameStateWithNilComments(t *testing.T) { - original := NewGame() - original.comments = nil - - clone := original.Clone() +func TestCopyDoesNotSetTree(t *testing.T) { + src := NewGame() + _, _ = src.MoveText("e4", SAN(), nil) - if clone.comments == nil { - t.Fatalf("expected comments to be initialized") + dst := &Game{} + dst.copy(src) + // copy() intentionally does not touch tree; every caller sets it explicitly. + if dst.tree != nil { + t.Fatalf("copy() must not alias or set the tree; got %v", dst.tree) } } @@ -971,7 +970,7 @@ func TestEligibleDrawsWithThreeRepetitions(t *testing.T) { g := NewGame() moves := []string{"Nf3", "Nf6", "Ng1", "Ng8", "Nf3", "Nf6", "Ng1", "Ng8", "Nf3", "Nf6"} for _, m := range moves { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } @@ -1078,8 +1077,8 @@ func TestPGNWithValidData(t *testing.T) { if len(g.Positions()) != 7 { t.Fatalf("expected 7 positions got %v", len(g.Positions())) } - if g.currentMove.String() != "a7a6" { - t.Fatalf("expected current move a7a6 but got %v", g.currentMove.String()) + if g.MoveTree().Current().Move().String() != "a7a6" { + t.Fatalf("expected current move a7a6 but got %v", g.MoveTree().Current().Move().String()) } } @@ -1124,7 +1123,7 @@ func TestGameString(t *testing.T) { name: "GameStringWithSingleMove", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) + _, _ = g.MoveText("e4", SAN(), nil) return g }, expected: "1. e4 *", @@ -1133,9 +1132,9 @@ func TestGameString(t *testing.T) { name: "GameStringWithMultipleMoves", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) - _ = g.PushMove("e5", nil) - _ = g.PushMove("Nf3", nil) + _, _ = g.MoveText("e4", SAN(), nil) + _, _ = g.MoveText("e5", SAN(), nil) + _, _ = g.MoveText("Nf3", SAN(), nil) return g }, expected: "1. e4 e5 2. Nf3 *", @@ -1144,15 +1143,15 @@ func TestGameString(t *testing.T) { name: "GameStringWithLongerGame", setup: func() *Game { g := NewGame() - _ = g.PushMove("Nf3", nil) - _ = g.PushMove("Nc6", nil) - _ = g.PushMove("Nc3", nil) - _ = g.PushMove("e6", nil) - _ = g.PushMove("e4", nil) - _ = g.PushMove("a6", nil) - _ = g.PushMove("Ne2", nil) - _ = g.PushMove("Nf6", nil) - _ = g.PushMove("Ned4", nil) + _, _ = g.MoveText("Nf3", SAN(), nil) + _, _ = g.MoveText("Nc6", SAN(), nil) + _, _ = g.MoveText("Nc3", SAN(), nil) + _, _ = g.MoveText("e6", SAN(), nil) + _, _ = g.MoveText("e4", SAN(), nil) + _, _ = g.MoveText("a6", SAN(), nil) + _, _ = g.MoveText("Ne2", SAN(), nil) + _, _ = g.MoveText("Nf6", SAN(), nil) + _, _ = g.MoveText("Ned4", SAN(), nil) return g }, expected: "1. Nf3 Nc6 2. Nc3 e6 3. e4 a6 4. Ne2 Nf6 5. Ned4 *", @@ -1161,8 +1160,8 @@ func TestGameString(t *testing.T) { name: "GameStringWithComments", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) - g.currentMove.comments = "Good move" + _, _ = g.MoveText("e4", SAN(), nil) + g.MoveTree().Current().SetComment("Good move") return g }, expected: "1. e4 {Good move} *", @@ -1171,11 +1170,11 @@ func TestGameString(t *testing.T) { name: "GameStringWithVariations", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) - _ = g.PushMove("e5", nil) - _ = g.PushMove("Nf3", nil) - g.GoBack() - _ = g.PushMove("Nc3", nil) + _, _ = g.MoveText("e4", SAN(), nil) + _, _ = g.MoveText("e5", SAN(), nil) + _, _ = g.MoveText("Nf3", SAN(), nil) + g.MoveTree().GoBack() + _, _ = g.MoveText("Nc3", SAN(), nil) return g }, expected: "1. e4 e5 2. Nf3 (2. Nc3) *", @@ -1221,9 +1220,9 @@ func TestGameString(t *testing.T) { name: "GameStringWithCommentsAndClock", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) - g.currentMove.comments = "Good move" - g.currentMove.SetCommand("clk", "10:00:00") + _, _ = g.MoveText("e4", SAN(), nil) + g.MoveTree().Current().SetComment("Good move") + g.MoveTree().Current().SetCommand("clk", "10:00:00") return g }, expected: "1. e4 {Good move [%clk 10:00:00]} *", @@ -1232,41 +1231,41 @@ func TestGameString(t *testing.T) { name: "GameStringWithCommandsOnly", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) - g.currentMove.SetCommand("eval", "0.24") - g.currentMove.SetCommand("clk", "10:00:00") + _, _ = g.MoveText("e4", SAN(), nil) + g.MoveTree().Current().SetCommand("eval", "0.24") + g.MoveTree().Current().SetCommand("clk", "10:00:00") return g }, - expected: "1. e4 { [%clk 10:00:00] [%eval 0.24]} *", + expected: "1. e4 { [%eval 0.24] [%clk 10:00:00]} *", }, { name: "GameStringWithCommentsAndMultipleCommands", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) - g.currentMove.comments = "Good move" - g.currentMove.SetCommand("eval", "0.24") - g.currentMove.SetCommand("clk", "10:00:00") + _, _ = g.MoveText("e4", SAN(), nil) + g.MoveTree().Current().SetComment("Good move") + g.MoveTree().Current().SetCommand("eval", "0.24") + g.MoveTree().Current().SetCommand("clk", "10:00:00") return g }, - expected: "1. e4 {Good move [%clk 10:00:00] [%eval 0.24]} *", + expected: "1. e4 {Good move [%eval 0.24] [%clk 10:00:00]} *", }, { name: "GameStringWithMultipleNestedVariations", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) - _ = g.PushMove("e5", nil) - _ = g.PushMove("Nf3", nil) - g.GoBack() - _ = g.PushMove("Nc3", nil) - g.GoBack() - _ = g.PushMove("d4", nil) - _ = g.PushMove("d5", nil) - _ = g.PushMove("c4", nil) - g.GoBack() - _ = g.PushMove("c3", nil) - g.GoBack() + _, _ = g.MoveText("e4", SAN(), nil) + _, _ = g.MoveText("e5", SAN(), nil) + _, _ = g.MoveText("Nf3", SAN(), nil) + g.MoveTree().GoBack() + _, _ = g.MoveText("Nc3", SAN(), nil) + g.MoveTree().GoBack() + _, _ = g.MoveText("d4", SAN(), nil) + _, _ = g.MoveText("d5", SAN(), nil) + _, _ = g.MoveText("c4", SAN(), nil) + g.MoveTree().GoBack() + _, _ = g.MoveText("c3", SAN(), nil) + g.MoveTree().GoBack() return g }, expected: "1. e4 e5 2. Nf3 (2. Nc3) (2. d4 d5 3. c4 (3. c3)) *", @@ -1275,14 +1274,14 @@ func TestGameString(t *testing.T) { name: "GameStringWithVariationsForBlack", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) - _ = g.PushMove("e5", nil) - _ = g.PushMove("Nf3", nil) - _ = g.PushMove("Nc6", nil) - _ = g.PushMove("Bb5", nil) - _ = g.PushMove("a6", nil) - g.GoBack() - _ = g.PushMove("d6", nil) + _, _ = g.MoveText("e4", SAN(), nil) + _, _ = g.MoveText("e5", SAN(), nil) + _, _ = g.MoveText("Nf3", SAN(), nil) + _, _ = g.MoveText("Nc6", SAN(), nil) + _, _ = g.MoveText("Bb5", SAN(), nil) + _, _ = g.MoveText("a6", SAN(), nil) + g.MoveTree().GoBack() + _, _ = g.MoveText("d6", SAN(), nil) return g }, expected: "1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 (3... d6) *", @@ -1291,9 +1290,9 @@ func TestGameString(t *testing.T) { name: "GameStringWithVariationsOnRoot", setup: func() *Game { g := NewGame() - _ = g.PushMove("e4", nil) - g.GoBack() - _ = g.PushMove("d4", nil) + _, _ = g.MoveText("e4", SAN(), nil) + g.MoveTree().GoBack() + _, _ = g.MoveText("d4", SAN(), nil) return g }, expected: "1. e4 (1. d4) *", @@ -1310,29 +1309,29 @@ func TestGameString(t *testing.T) { } } -func FuzzTestPushNotationMove(f *testing.F) { +func FuzzTestMoveText(f *testing.F) { f.Add("e2e4", 0) f.Add("e4", 1) f.Add("Nb1c3", 2) - f.Fuzz(func(t *testing.T, move string, notationType int) { + f.Fuzz(func(_ *testing.T, move string, codecType int) { game := NewGame() - var notation Notation - switch notationType % 3 { + var codec MoveTextCodec + switch codecType % 3 { case 0: - notation = UCINotation{} + codec = UCI() case 1: - notation = AlgebraicNotation{} + codec = SAN() case 2: - notation = LongAlgebraicNotation{} + codec = LongAlgebraic() } - _ = game.PushNotationMove(move, notation, nil) + _, _ = game.MoveText(move, codec, nil) }) } -func TestInvalidPushNotationMove(t *testing.T) { +func TestInvalidMoveText(t *testing.T) { fen := "r1bqk1nr/pp1pppbp/6p1/1Bp1P3/P2n1P2/2N2N2/1PPP2PP/R1BQK2R w KQkq - 0 1" bogusMv := "Kxh1" opt, err := FEN(fen) @@ -1341,17 +1340,17 @@ func TestInvalidPushNotationMove(t *testing.T) { } game := NewGame(opt) - err = game.PushNotationMove(bogusMv, UCINotation{}, nil) + _, err = game.MoveText(bogusMv, UCI(), nil) if err == nil { - t.Errorf("PushNotationMove() (uci) succeeded in pushing bogus mv when it should have failed") + t.Errorf("MoveText() (uci) succeeded in pushing bogus mv when it should have failed") } - err = game.PushNotationMove(bogusMv, AlgebraicNotation{}, nil) + _, err = game.MoveText(bogusMv, SAN(), nil) if err == nil { - t.Errorf("PushNotationMove() (alg) succeeded in pushing bogus mv when it should have failed") + t.Errorf("MoveText() (SAN) succeeded in pushing bogus mv when it should have failed") } } -func TestValidPushNotationMove(t *testing.T) { +func TestValidMoveText(t *testing.T) { pgn := strings.NewReader("1. e4 (1. g4) 1... c5 2. Nc3 Nc6 3. f4 g6 4. Nf3 Bg7 5. a4 Nf6 6. e5 *") mv := "Ng4" opt, err := PGN(pgn) @@ -1363,25 +1362,24 @@ func TestValidPushNotationMove(t *testing.T) { startMlen := len(game.Moves()) startPlen := len(game.Positions()) - err = game.PushNotationMove(mv, AlgebraicNotation{}, &PushMoveOptions{ - ForceMainline: true, + _, err = game.MoveText(mv, SAN(), &MoveInsertOptions{ + PromoteToMainLine: true, }) if err != nil { - t.Errorf("PushNotationMove() failed but should have succeeded") + t.Errorf("MoveText() failed but should have succeeded") } if len(game.Moves()) != startMlen+1 { - t.Errorf("PushNotationMove() failed to update game.Moves()") + t.Errorf("MoveText() failed to update game.Moves()") } if len(game.Positions()) != startPlen+1 { - t.Errorf("PushNotationMove() failed to update game.Positions()") + t.Errorf("MoveText() failed to update game.Positions()") } } func validateSplit(t *testing.T, origPgn string, expectedLastLines []string) { reader := strings.NewReader(origPgn) - scanner := NewScanner(reader) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(reader).Decode() if err != nil { t.Fatalf("fail to parse game: %s", err.Error()) } @@ -1437,12 +1435,12 @@ func TestRootMoveComments(t *testing.T) { game := NewGame() // Add a comment to the root move - root := game.GetRootMove() + root := game.MoveTree().Root() root.AddComment("This is a comment before the first move") // Add some moves - game.PushMove("e4", nil) - game.PushMove("e5", nil) + game.MoveText("e4", SAN(), nil) + game.MoveText("e5", SAN(), nil) // Generate PGN pgn := game.String() @@ -1479,7 +1477,7 @@ func TestRootMoveComments(t *testing.T) { game := NewGame() // Add a comment to the root move - root := game.GetRootMove() + root := game.MoveTree().Root() root.AddComment("Comment on empty game") // Generate PGN @@ -1495,12 +1493,12 @@ func TestRootMoveComments(t *testing.T) { game := NewGame() // Add multiple comments to the root move - root := game.GetRootMove() + root := game.MoveTree().Root() root.AddComment("First comment. ") root.AddComment("Second comment.") // Add some moves - game.PushMove("e4", nil) + game.MoveText("e4", SAN(), nil) // Generate PGN pgn := game.String() @@ -1519,11 +1517,11 @@ func TestRootMoveComments(t *testing.T) { game.AddTagPair("Site", "Test Site") // Add a comment to the root move - root := game.GetRootMove() + root := game.MoveTree().Root() root.AddComment("Comment with tags") // Add some moves - game.PushMove("e4", nil) + game.MoveText("e4", SAN(), nil) // Generate PGN pgn := game.String() @@ -1565,14 +1563,14 @@ func TestRootMoveComments(t *testing.T) { game := NewGame() // Add a comment to the root move - root := game.GetRootMove() + root := game.MoveTree().Root() root.AddComment("Comment before variations") // Add moves and create variations - game.PushMove("e4", nil) - game.PushMove("e5", nil) - game.GoBack() - game.PushMove("d5", nil) + game.MoveText("e4", SAN(), nil) + game.MoveText("e5", SAN(), nil) + game.MoveTree().GoBack() + game.MoveText("d5", SAN(), nil) // Generate PGN pgn := game.String() @@ -1602,60 +1600,6 @@ func TestRootMoveComments(t *testing.T) { }) } -func TestWriteAnnotationsLegacyBranches(t *testing.T) { - t.Run("NilMove", func(t *testing.T) { - var sb strings.Builder - writeAnnotations(nil, &sb) - if sb.String() != "" { - t.Fatalf("expected empty annotation output, got %q", sb.String()) - } - }) - - t.Run("CommentOnly", func(t *testing.T) { - move := &Move{comments: "Good move"} - move.ensureCommentBlocksFromLegacy() - move.commentBlocks = nil - - var sb strings.Builder - writeAnnotations(move, &sb) - if sb.String() != " {Good move}" { - t.Fatalf("expected comment-only annotation, got %q", sb.String()) - } - }) - - t.Run("CommandOnly", func(t *testing.T) { - move := &Move{command: map[string]string{"clk": "0:05:00"}} - move.ensureCommentBlocksFromLegacy() - move.commentBlocks = nil - - var sb strings.Builder - writeAnnotations(move, &sb) - if sb.String() != " { [%clk 0:05:00]}" { - t.Fatalf("expected command-only annotation, got %q", sb.String()) - } - }) - - t.Run("CommentAndCommand", func(t *testing.T) { - move := &Move{comments: "Good move", command: map[string]string{"clk": "0:05:00"}} - move.ensureCommentBlocksFromLegacy() - move.commentBlocks = nil - - var sb strings.Builder - writeAnnotations(move, &sb) - if sb.String() != " {Good move [%clk 0:05:00]}" { - t.Fatalf("expected merged annotation, got %q", sb.String()) - } - }) - - t.Run("EmptyStructuredBlock", func(t *testing.T) { - var sb strings.Builder - writeCommentBlocks([]CommentBlock{{}}, &sb) - if sb.String() != "" { - t.Fatalf("expected empty structured block to be skipped, got %q", sb.String()) - } - }) -} - func TestValidateSAN(t *testing.T) { tests := []struct { name string @@ -1911,13 +1855,13 @@ func TestGameMoveValidation(t *testing.T) { tests := []struct { name string setupMoves []string // Moves to set up the position - move *Move // Move to test + move Move // Move to test wantErr bool // Whether we expect an error errorString string // Expected error string (if wantErr is true) }{ { name: "valid move should succeed", - move: &Move{ + move: Move{ s1: E2, s2: E4, }, @@ -1925,33 +1869,27 @@ func TestGameMoveValidation(t *testing.T) { }, { name: "invalid move should fail", - move: &Move{ + move: Move{ s1: E2, s2: E5, // Invalid move - pawn can't move three squares from e2 to e5 }, wantErr: true, - errorString: "move e2e5 is not valid for the current position", - }, - { - name: "nil move should fail", - move: nil, - wantErr: true, - errorString: "move cannot be nil", + errorString: "chess: illegal move e2e5", }, { name: "invalid move from valid position should fail", setupMoves: []string{"e4", "e5"}, - move: &Move{ + move: Move{ s1: E4, s2: E6, // Invalid move - pawn can't move two squares from e4 to e6 }, wantErr: true, - errorString: "move e4e6 is not valid for the current position", + errorString: "chess: illegal move e4e6", }, { name: "valid move from valid position should succeed", setupMoves: []string{"e4", "e5"}, - move: &Move{ + move: Move{ s1: G1, s2: F3, }, @@ -1960,7 +1898,7 @@ func TestGameMoveValidation(t *testing.T) { { name: "valid promotion move should succeed", setupMoves: []string{"e4", "d5", "exd5", "c6", "dxc6", "Nf6", "cxb7", "Nbd7"}, - move: &Move{ + move: Move{ s1: B7, s2: A8, promo: Queen, @@ -1970,18 +1908,18 @@ func TestGameMoveValidation(t *testing.T) { { name: "invalid promotion move should fail", setupMoves: []string{"e4", "d5", "exd5", "c6", "dxc6", "Nf6", "cxb7", "Nbd7"}, - move: &Move{ + move: Move{ s1: B7, s2: A8, promo: King, // Invalid promotion piece }, wantErr: true, - errorString: "move b7a8k is not valid for the current position", + errorString: "chess: illegal move b7a8k", }, { name: "valid castling move should succeed", setupMoves: []string{"e4", "e5", "Nf3", "Nc6", "Bc4", "Bc5", "d3", "Nf6"}, - move: &Move{ + move: Move{ s1: E1, s2: G1, tags: KingSideCastle, @@ -1991,13 +1929,13 @@ func TestGameMoveValidation(t *testing.T) { { name: "invalid castling move should fail", setupMoves: []string{"e4", "e5", "Nf3", "Nc6", "Bc4", "Bc5", "d3", "Nf6"}, - move: &Move{ + move: Move{ s1: E1, s2: H1, // Invalid castling destination tags: KingSideCastle, }, wantErr: true, - errorString: "move e1h1 is not valid for the current position", + errorString: "chess: illegal move e1h1", }, } @@ -2008,14 +1946,14 @@ func TestGameMoveValidation(t *testing.T) { // Setup moves for _, move := range tt.setupMoves { - err := game.PushMove(move, nil) + _, err := game.MoveText(move, SAN(), nil) if err != nil { t.Fatalf("setup failed: %v", err) } } // Test the move - err := game.Move(tt.move, nil) + _, err := game.Move(tt.move, nil) // Check error expectation if (err != nil) != tt.wantErr { @@ -2024,24 +1962,24 @@ func TestGameMoveValidation(t *testing.T) { } if tt.wantErr { - if tt.errorString != "" && err.Error() != tt.errorString { - t.Errorf("Move() error = %v, want error string %v", err.Error(), tt.errorString) + if tt.errorString != "" && !strings.Contains(err.Error(), tt.errorString) { + t.Errorf("Move() error = %v, want error string to contain %v", err.Error(), tt.errorString) } return } - // If the move was successful, verify it was added to the game - if tt.move != nil { - // Check that the current move matches our move - if game.currentMove == nil { - t.Errorf("Move() succeeded but currentMove is nil") - return - } + // Check that the current move matches our move by identity (origin, + // destination, promotion). Position-derived tags may differ between + // the caller-supplied and stored Move because the canon stores the + // generated Move; tags are derived, not part of Move identity. + if game.MoveTree().Current() == nil { + t.Errorf("Move() succeeded but currentMove is nil") + return + } - if game.currentMove.s1 != tt.move.s1 || game.currentMove.s2 != tt.move.s2 || game.currentMove.promo != tt.move.promo { - t.Errorf("Move() succeeded but currentMove doesn't match: got %v, want %v", - game.currentMove, tt.move) - } + stored := game.MoveTree().Current().Move() + if stored.S1() != tt.move.S1() || stored.S2() != tt.move.S2() || stored.Promo() != tt.move.Promo() { + t.Errorf("Move() identity mismatch: got %v, want %v", stored, tt.move) } }) } @@ -2051,12 +1989,12 @@ func TestGameUnsafeMove(t *testing.T) { tests := []struct { name string setupMoves []string // Moves to set up the position - move *Move // Move to test + move Move // Move to test wantErr bool // Whether we expect an error }{ { name: "valid move should succeed without validation", - move: &Move{ + move: Move{ s1: E2, s2: E4, }, @@ -2064,21 +2002,16 @@ func TestGameUnsafeMove(t *testing.T) { }, { name: "invalid move should still succeed (no validation)", - move: &Move{ + move: Move{ s1: E2, s2: E5, // Invalid move but UnsafeMove doesn't validate }, wantErr: false, // UnsafeMove doesn't validate, so no error expected }, - { - name: "nil move should fail", - move: nil, - wantErr: true, - }, { name: "complex valid move should succeed", setupMoves: []string{"e4", "e5"}, - move: &Move{ + move: Move{ s1: G1, s2: F3, }, @@ -2087,7 +2020,7 @@ func TestGameUnsafeMove(t *testing.T) { { name: "promotion move should succeed without validation", setupMoves: []string{"e4", "d5", "exd5", "c6", "dxc6", "Nf6", "cxb7", "Nbd7"}, - move: &Move{ + move: Move{ s1: B7, s2: A8, promo: Queen, @@ -2103,14 +2036,14 @@ func TestGameUnsafeMove(t *testing.T) { // Setup moves for _, move := range tt.setupMoves { - err := game.PushMove(move, nil) + _, err := game.MoveText(move, SAN(), nil) if err != nil { t.Fatalf("setup failed: %v", err) } } // Test the move - err := game.UnsafeMove(tt.move, nil) + _, err := game.UnsafeMove(tt.move, nil) // Check error expectation if (err != nil) != tt.wantErr { @@ -2122,18 +2055,17 @@ func TestGameUnsafeMove(t *testing.T) { return } - // If the move was successful, verify it was added to the game - if tt.move != nil { - // Check that the current move matches our move - if game.currentMove == nil { - t.Errorf("UnsafeMove() succeeded but currentMove is nil") - return - } + // Check that the current move matches our move by identity (origin, + // destination, promotion). UnsafeMove trusts the caller, so the stored + // Move carries the caller's tags verbatim. + if game.MoveTree().Current() == nil { + t.Errorf("UnsafeMove() succeeded but currentMove is nil") + return + } - if game.currentMove.s1 != tt.move.s1 || game.currentMove.s2 != tt.move.s2 || game.currentMove.promo != tt.move.promo { - t.Errorf("UnsafeMove() succeeded but currentMove doesn't match: got %v, want %v", - game.currentMove, tt.move) - } + stored := game.MoveTree().Current().Move() + if stored.S1() != tt.move.S1() || stored.S2() != tt.move.S2() || stored.Promo() != tt.move.Promo() { + t.Errorf("UnsafeMove() identity mismatch: got %v, want %v", stored, tt.move) } }) } @@ -2151,13 +2083,13 @@ func TestMoveVsUnsafeMovePerformance(t *testing.T) { t.Fatal("no valid moves available") } - move := &validMoves[0] + move := validMoves[0] // Test Move (with validation) start := time.Now() - for i := 0; i < 1000; i++ { + for range 1000 { gameClone := game.Clone() - err := gameClone.Move(move, nil) + _, err := gameClone.Move(move, nil) if err != nil { t.Fatalf("Move failed: %v", err) } @@ -2166,9 +2098,9 @@ func TestMoveVsUnsafeMovePerformance(t *testing.T) { // Test UnsafeMove (without validation) start = time.Now() - for i := 0; i < 1000; i++ { + for range 1000 { gameClone := game.Clone() - err := gameClone.UnsafeMove(move, nil) + _, err := gameClone.UnsafeMove(move, nil) if err != nil { t.Fatalf("UnsafeMove failed: %v", err) } @@ -2185,50 +2117,37 @@ func TestMoveVsUnsafeMovePerformance(t *testing.T) { } } -func TestUnsafePushNotationMove(t *testing.T) { +func TestUnsafeMoveText(t *testing.T) { tests := []struct { name string setupMoves []string // Moves to set up the position moveStr string // Move to test - notation Notation // Notation to use - wantErr bool // Whether we expect an error + codec MoveTextCodec + wantErr bool // Whether we expect an error }{ { - name: "valid algebraic move should succeed without validation", - moveStr: "e4", - notation: AlgebraicNotation{}, - wantErr: false, - }, - { - name: "valid UCI move should succeed without validation", - moveStr: "e2e4", - notation: UCINotation{}, - wantErr: false, - }, - { - name: "valid long algebraic move should succeed without validation", - moveStr: "e2e4", - notation: LongAlgebraicNotation{}, - wantErr: false, + name: "valid UCI move should succeed without validation", + moveStr: "e2e4", + codec: UCI(), + wantErr: false, }, { - name: "invalid notation should fail during parsing", - moveStr: "xyz", - notation: AlgebraicNotation{}, - wantErr: true, // This should fail at notation parsing, not validation + name: "valid long algebraic move should succeed without validation", + moveStr: "e2e4", + codec: LongAlgebraic(), + wantErr: false, }, { - name: "complex valid move should succeed", - setupMoves: []string{"e4", "e5"}, - moveStr: "Nf3", - notation: AlgebraicNotation{}, - wantErr: false, + name: "invalid notation should fail during parsing", + moveStr: "xyz", + codec: UCI(), + wantErr: true, // This should fail at notation parsing, not validation }, { name: "invalid move should still succeed (no validation)", setupMoves: []string{"e4", "e5"}, - moveStr: "e2e3", // This move is illegal but UnsafePushNotationMove doesn't validate - notation: UCINotation{}, + moveStr: "e2e3", // This move is illegal but UnsafePushMoveText doesn't validate + codec: UCI(), wantErr: false, // No validation, so no error expected }, } @@ -2240,18 +2159,18 @@ func TestUnsafePushNotationMove(t *testing.T) { // Setup moves for _, move := range tt.setupMoves { - err := game.PushNotationMove(move, AlgebraicNotation{}, nil) + _, err := game.MoveText(move, SAN(), nil) if err != nil { t.Fatalf("setup failed: %v", err) } } // Test the move - err := game.UnsafePushNotationMove(tt.moveStr, tt.notation, nil) + _, err := game.UnsafeMoveText(tt.moveStr, tt.codec, nil) // Check error expectation if (err != nil) != tt.wantErr { - t.Errorf("UnsafePushNotationMove() error = %v, wantErr %v", err, tt.wantErr) + t.Errorf("UnsafeMoveText() error = %v, wantErr %v", err, tt.wantErr) return } @@ -2260,22 +2179,22 @@ func TestUnsafePushNotationMove(t *testing.T) { } // If the move was successful, verify it was added to the game - if game.currentMove == nil { - t.Errorf("UnsafePushNotationMove() succeeded but currentMove is nil") + if game.MoveTree().Current() == nil { + t.Errorf("UnsafeMoveText() succeeded but currentMove is nil") return } // For successful cases, just verify that some move was made moves := game.Moves() if len(moves) == 0 { - t.Errorf("UnsafePushNotationMove() succeeded but no moves in game") + t.Errorf("UnsafeMoveText() succeeded but no moves in game") } }) } } -// TestPushNotationMoveVsUnsafePushNotationMovePerformance demonstrates the performance difference -func TestPushNotationMoveVsUnsafePushNotationMovePerformance(t *testing.T) { +// TestPushMoveTextVsUnsafePushMoveTextPerformance demonstrates the performance difference. +func TestPushMoveTextVsUnsafePushMoveTextPerformance(t *testing.T) { if testing.Short() { t.Skip("skipping performance test in short mode") } @@ -2284,37 +2203,37 @@ func TestPushNotationMoveVsUnsafePushNotationMovePerformance(t *testing.T) { // Test with a common opening move moveStr := "e4" - notation := AlgebraicNotation{} + unsafeMoveStr := "e2e4" - // Test PushNotationMove (with validation) + // Test PushMoveText (with validation) start := time.Now() - for i := 0; i < 1000; i++ { + for range 1000 { gameClone := game.Clone() - err := gameClone.PushNotationMove(moveStr, notation, nil) + _, err := gameClone.MoveText(moveStr, SAN(), nil) if err != nil { - t.Fatalf("PushNotationMove failed: %v", err) + t.Fatalf("PushMoveText failed: %v", err) } } pushNotationMoveTime := time.Since(start) - // Test UnsafePushNotationMove (without validation) + // Test UnsafePushMoveText (without validation) start = time.Now() - for i := 0; i < 1000; i++ { + for range 1000 { gameClone := game.Clone() - err := gameClone.UnsafePushNotationMove(moveStr, notation, nil) + _, err := gameClone.UnsafeMoveText(unsafeMoveStr, UCI(), nil) if err != nil { - t.Fatalf("UnsafePushNotationMove failed: %v", err) + t.Fatalf("UnsafePushMoveText failed: %v", err) } } unsafePushNotationMoveTime := time.Since(start) - t.Logf("PushNotationMove() (with validation): %v", pushNotationMoveTime) - t.Logf("UnsafePushNotationMove() (no validation): %v", unsafePushNotationMoveTime) + t.Logf("MoveText() (with validation): %v", pushNotationMoveTime) + t.Logf("UnsafeMoveText() (no validation): %v", unsafePushNotationMoveTime) t.Logf("Performance improvement: %.2fx", float64(pushNotationMoveTime)/float64(unsafePushNotationMoveTime)) - // UnsafePushNotationMove should be faster + // UnsafePushMoveText should be faster if unsafePushNotationMoveTime >= pushNotationMoveTime { - t.Logf("Warning: UnsafePushNotationMove wasn't faster than PushNotationMove - this might be expected for simple positions") + t.Logf("Warning: UnsafePushMoveText wasn't faster than PushMoveText - this might be expected for simple positions") } } @@ -2417,11 +2336,11 @@ func TestCastlingInteractions(t *testing.T) { // Make first move pos := g.Position() - m1, err := AlgebraicNotation{}.Decode(pos, tt.firstMove) + m1, err := decodeSANText(pos, tt.firstMove, true) if err != nil { t.Fatalf("Failed to decode first move %s: %v", tt.firstMove, err) } - if err := g.Move(m1, nil); err != nil { + if _, err := g.Move(m1, nil); err != nil { t.Fatalf("Failed to make first move %s: %v", tt.firstMove, err) } @@ -2451,96 +2370,87 @@ func TestCastlingInteractions(t *testing.T) { } } -func TestMoveHistoryEmptyGame(t *testing.T) { +func TestMoveListEmptyGame(t *testing.T) { g := NewGame() - history := g.MoveHistory() - if len(history) != 0 { - t.Fatalf("expected empty move history, got %d", len(history)) + list := g.MoveList() + if len(list) != 0 { + t.Fatalf("expected empty move list, got %d", len(list)) } } -func TestMoveHistoryMainLine(t *testing.T) { +func TestMoveListMainLine(t *testing.T) { g := NewGame() for _, m := range []string{"e4", "e5", "Nf3"} { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } - history := g.MoveHistory() - if len(history) != 3 { - t.Fatalf("expected 3 move history entries, got %d", len(history)) - } - if history[0].Move.String() != "e2e4" { - t.Fatalf("expected first move e2e4, got %s", history[0].Move) - } - if history[0].PrePosition != g.rootMove.position { - t.Fatalf("expected first pre-position to be root position") + list := g.MoveList() + if len(list) != 3 { + t.Fatalf("expected 3 move list entries, got %d", len(list)) } - if history[0].PostPosition != history[0].Move.position { - t.Fatalf("expected post-position to match move position") - } - if history[1].PrePosition != history[0].PostPosition { - t.Fatalf("expected second pre-position to match first post-position") + if list[0].Move.String() != "e2e4" { + t.Fatalf("expected first move e2e4, got %s", list[0].Move) } } -func TestMoveHistoryComments(t *testing.T) { +func TestMoveListComments(t *testing.T) { g := NewGame() - if err := g.PushMove("e4", nil); err != nil { + if _, err := g.MoveText("e4", SAN(), nil); err != nil { t.Fatal(err) } - g.currentMove.SetComment("good move") - history := g.MoveHistory() - if len(history) != 1 { - t.Fatalf("expected 1 move history entry, got %d", len(history)) + g.MoveTree().Current().SetComment("good move") + list := g.MoveList() + if len(list) != 1 { + t.Fatalf("expected 1 move list entry, got %d", len(list)) } - if len(history[0].Comments) != 1 || history[0].Comments[0] != "good move" { - t.Fatalf("expected comment %q, got %v", "good move", history[0].Comments) + if len(list[0].Comments) != 1 || list[0].Comments[0] != "good move" { + t.Fatalf("expected comment %q, got %v", "good move", list[0].Comments) } } -func TestMoveHistoryNoComments(t *testing.T) { +func TestMoveListNoComments(t *testing.T) { g := NewGame() - if err := g.PushMove("e4", nil); err != nil { + if _, err := g.MoveText("e4", SAN(), nil); err != nil { t.Fatal(err) } - history := g.MoveHistory() - if len(history[0].Comments) != 0 { - t.Fatalf("expected no comments, got %v", history[0].Comments) + list := g.MoveList() + if len(list[0].Comments) != 0 { + t.Fatalf("expected no comments, got %v", list[0].Comments) } } -func TestMoveHistoryWithVariations(t *testing.T) { +func TestMoveListWithVariations(t *testing.T) { g := NewGame() - if err := g.PushMove("e4", nil); err != nil { + if _, err := g.MoveText("e4", SAN(), nil); err != nil { t.Fatal(err) } - if err := g.PushMove("e5", nil); err != nil { + if _, err := g.MoveText("e5", SAN(), nil); err != nil { t.Fatal(err) } - variationMove := &Move{} - g.AddVariation(g.rootMove.children[0], variationMove) - history := g.MoveHistory() - if len(history) != 2 { - t.Fatalf("expected 2 main line entries (variations excluded), got %d", len(history)) + variationMove := Move{} + g.MoveTree().AddVariation(g.MoveTree().Root().children[0], variationMove) + list := g.MoveList() + if len(list) != 2 { + t.Fatalf("expected 2 main line entries (variations excluded), got %d", len(list)) } } -func TestMoveHistoryMatchesMovesLength(t *testing.T) { +func TestMoveListMatchesMovesLength(t *testing.T) { g := NewGame() for _, m := range []string{"e4", "e5", "Nf3", "Nc6", "Bb5"} { - if err := g.PushMove(m, nil); err != nil { + if _, err := g.MoveText(m, SAN(), nil); err != nil { t.Fatal(err) } } moves := g.Moves() - history := g.MoveHistory() - if len(history) != len(moves) { - t.Fatalf("expected history length %d to match moves length %d", len(history), len(moves)) + list := g.MoveList() + if len(list) != len(moves) { + t.Fatalf("expected list length %d to match moves length %d", len(list), len(moves)) } } -func TestMoveHistoryFromPGN(t *testing.T) { +func TestMoveListFromPGN(t *testing.T) { pgnData := mustParsePGN("fixtures/pgns/single_game.pgn") r := strings.NewReader(pgnData) opt, err := PGN(r) @@ -2549,24 +2459,9 @@ func TestMoveHistoryFromPGN(t *testing.T) { } game := NewGame(opt) - history := game.MoveHistory() - if len(history) == 0 { - t.Fatal("expected move history from PGN game") - } - - for i, h := range history { - if h.Move == nil { - t.Fatalf("entry %d: Move is nil", i) - } - if h.PrePosition == nil { - t.Fatalf("entry %d: PrePosition is nil", i) - } - if h.PostPosition == nil { - t.Fatalf("entry %d: PostPosition is nil", i) - } - if i > 0 && h.PrePosition != history[i-1].PostPosition { - t.Fatalf("entry %d: PrePosition should match previous PostPosition", i) - } + list := game.MoveList() + if len(list) == 0 { + t.Fatal("expected move list from PGN game") } } diff --git a/game_unsafe_move_text_test.go b/game_unsafe_move_text_test.go new file mode 100644 index 00000000..1f1b774f --- /dev/null +++ b/game_unsafe_move_text_test.go @@ -0,0 +1,88 @@ +package chess_test + +import ( + "errors" + "testing" + + "github.com/corentings/chess/v3" +) + +func TestGameUnsafePushMoveTextRejectsSAN(t *testing.T) { + _, err := chess.NewGame().UnsafeMoveText("e4", chess.SAN(), nil) + if !errors.Is(err, chess.ErrUnsafeMoveTextUnsupported) { + t.Fatalf("UnsafeMoveText(SAN) error = %v, want ErrUnsafeMoveTextUnsupported", err) + } +} + +func TestGameUnsafePushMoveTextAcceptsIllegalCoordinateMove(t *testing.T) { + game := chess.NewGame() + if _, err := game.UnsafeMoveText("e2e5", chess.UCI(), nil); err != nil { + t.Fatalf("UnsafeMoveText() error = %v", err) + } + if got := game.Position().Board().Piece(chess.E5); got != chess.WhitePawn { + t.Fatalf("piece on e5 = %v, want white pawn", got) + } +} + +func TestGameUnsafePushMoveTextClassifiesSpecialMoves(t *testing.T) { + t.Run("capture from UCI", func(t *testing.T) { + game := chess.NewGame() + mustUnsafeMoveText(t, game, "e2e4", chess.UCI()) + mustUnsafeMoveText(t, game, "d7d5", chess.UCI()) + node := mustUnsafeMoveText(t, game, "e4d5", chess.UCI()) + if !node.Move().HasTag(chess.Capture) { + t.Fatalf("capture move missing Capture tag: %v", node.Move()) + } + }) + + t.Run("castling from UCI", func(t *testing.T) { + game := mustGameFromFEN(t, "r3k2r/8/8/8/8/8/8/R3K2R w KQkq - 0 1") + node := mustUnsafeMoveText(t, game, "e1g1", chess.UCI()) + if !node.Move().HasTag(chess.KingSideCastle) { + t.Fatalf("castle move missing KingSideCastle tag: %v", node.Move()) + } + if got := game.Position().Board().Piece(chess.F1); got != chess.WhiteRook { + t.Fatalf("piece on f1 = %v, want white rook", got) + } + }) + + t.Run("en passant from long algebraic", func(t *testing.T) { + game := mustGameFromFEN(t, "rnbqkbnr/pp2pppp/8/2ppP3/8/8/PPPP1PPP/RNBQKBNR w KQkq d6 0 3") + node := mustUnsafeMoveText(t, game, "e5xd6", chess.LongAlgebraic()) + if !node.Move().HasTag(chess.EnPassant) { + t.Fatalf("en passant move missing EnPassant tag: %v", node.Move()) + } + if got := game.Position().Board().Piece(chess.D5); got != chess.NoPiece { + t.Fatalf("piece on d5 = %v, want empty square", got) + } + }) + + t.Run("null move from UCI", func(t *testing.T) { + game := chess.NewGame() + node := mustUnsafeMoveText(t, game, "0000", chess.UCI()) + if !node.Move().HasTag(chess.Null) { + t.Fatalf("null move missing Null tag: %v", node.Move()) + } + if game.Position().Turn() != chess.Black { + t.Fatalf("turn = %v, want black", game.Position().Turn()) + } + }) +} + +func mustUnsafeMoveText(t *testing.T, game *chess.Game, moveText string, codec chess.MoveTextCodec) *chess.MoveNode { + t.Helper() + node, err := game.UnsafeMoveText(moveText, codec, nil) + if err != nil { + t.Fatalf("UnsafeMoveText(%q, %s) error = %v", moveText, codec, err) + } + return node +} + +func mustGameFromFEN(t *testing.T, fen string) *chess.Game { + t.Helper() + opt, err := chess.FEN(fen) + if err != nil { + t.Fatalf("FEN() error = %v", err) + } + return chess.NewGame(opt) +} diff --git a/go.mod b/go.mod index 13931e98..ae2eb35c 100644 --- a/go.mod +++ b/go.mod @@ -1,5 +1,5 @@ -module github.com/corentings/chess/v2 +module github.com/corentings/chess/v3 go 1.25.0 -require github.com/ajstarks/svgo v0.0.0-20211024235047-1546f124cd8b +require go.uber.org/goleak v1.3.0 diff --git a/go.sum b/go.sum index 38027bab..d39b9ad7 100644 --- a/go.sum +++ b/go.sum @@ -1,29 +1,10 @@ -github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU= -github.com/ajstarks/deck v0.0.0-20200831202436-30c9fc6549a9/go.mod h1:JynElWSGnm/4RlzPXRlREEwqTHAN3T56Bv2ITsFT3gY= -github.com/ajstarks/deck/generate v0.0.0-20210309230005-c3f852c02e19/go.mod h1:T13YZdzov6OU0A1+RfKZiZN9ca6VeKdBdyDV+BY97Tk= -github.com/ajstarks/svgo v0.0.0-20211024235047-1546f124cd8b h1:slYM766cy2nI3BwyRiyQj/Ud48djTMtMebDqepE95rw= -github.com/ajstarks/svgo v0.0.0-20211024235047-1546f124cd8b/go.mod h1:1KcenG0jGWcpt8ov532z81sp/kMMUG485J2InIOyADM= -github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck= -github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74= -golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w= -golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI= -golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto= -golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA= -golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg= -golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s= -golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU= -golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= -golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= -golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= -golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= -golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= -golang.org/x/sys v0.0.0-20210119212857-b64e53b001e4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= -golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ= -golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ= -golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ= -golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo= -golang.org/x/tools v0.1.0/go.mod h1:xkSsbof2nBLbhDlRMhhhyNLN/zl3eTqcnHD5viDpcZ0= -golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= -golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= -golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= -honnef.co/go/tools v0.1.3/go.mod h1:NgwopIslSNH47DimFoV78dnkksY2EFtX0ajyb3K/las= +github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c= +github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= +github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM= +github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= +github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk= +github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU= +go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto= +go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE= +gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA= +gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= diff --git a/hashes.go b/hashes.go index f984bffd..7ef80a03 100644 --- a/hashes.go +++ b/hashes.go @@ -1,23 +1,10 @@ package chess import ( - "encoding/hex" "fmt" "strconv" ) -var polyglotHashesBytes = func() [len(polyglotHashes)][8]byte { - var hashes [len(polyglotHashes)][8]byte - for i, hexStr := range polyglotHashes { - b, err := hex.DecodeString(hexStr) - if err != nil { - panic(fmt.Errorf("invalid polyglot hash at index %d: %w", i, err)) - } - copy(hashes[i][:], b) - } - return hashes -}() - // polyglotHashesUint64 provides the same hashes as uint64 values for fast XOR operations. var polyglotHashesUint64 = func() [len(polyglotHashes)]uint64 { var hashes [len(polyglotHashes)]uint64 @@ -31,15 +18,7 @@ var polyglotHashesUint64 = func() [len(polyglotHashes)]uint64 { return hashes }() -// GetPolyglotHashBytes returns a precomputed byte slice for a given index -func GetPolyglotHashBytes(index int) []byte { - if index < 0 || index >= len(polyglotHashesBytes) { - return nil - } - return polyglotHashesBytes[index][:] -} - -// GetPolyglotHashes returns a reference to the static hash array +// GetPolyglotHashes returns a reference to the static hash array. func GetPolyglotHashes() []string { return polyglotHashes[:] } diff --git a/helpers_test.go b/helpers_test.go new file mode 100644 index 00000000..114e902a --- /dev/null +++ b/helpers_test.go @@ -0,0 +1,56 @@ +package chess_test + +import ( + "io" + "os" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +func mustReadFile(fname string) string { + f, err := os.Open(fname) + if err != nil { + panic(err) + } + defer f.Close() + b, err := io.ReadAll(f) + if err != nil { + panic(err) + } + return string(b) +} + +func mustPGNOption(t *testing.T, pgn string) func(*chess.Game) { + t.Helper() + opt, err := chess.PGN(strings.NewReader(pgn)) + if err != nil { + t.Fatal(err) + } + return opt +} + +func mustParseSingleGame(t *testing.T, pgn string) *chess.Game { + t.Helper() + game, err := chess.ParsePGN(strings.NewReader(pgn)) + if err != nil { + t.Fatalf("failed to parse pgn: %v", err) + } + if game == nil { + t.Fatal("expected game") + } + return game +} + +func withMinimalTags(moveText string) string { + return `[Event "Test"] +[Site "Internet"] +[Date "2026.06.19"] +[Round "1"] +[White "White"] +[Black "Black"] +[Result "*"] + +` + moveText +} diff --git a/image/.DS_Store b/image/.DS_Store deleted file mode 100644 index ac3d6204..00000000 Binary files a/image/.DS_Store and /dev/null differ diff --git a/image/README.md b/image/README.md index 7ec7fd07..7730763d 100644 --- a/image/README.md +++ b/image/README.md @@ -2,95 +2,132 @@ ## Introduction -**image** is an chess image utility that converts board positions into [SVG](https://en.wikipedia.org/wiki/Scalable_Vector_Graphics), or Scalable Vector Graphics, images. [svgo](https://github.com/ajstarks/svgo), the only outside dependency, is used to construct the SVG document. +**image** is a chess image utility that converts board positions into [SVG](https://en.wikipedia.org/wiki/Scalable_Vector_Graphics), or Scalable Vector Graphics, images. The package has no external dependencies; SVG is written directly to an `io.Writer`. + +### Piece Set + +The package ships with a single fixed piece set embedded from `internal/pieces/` (one SVG per color and piece type: `wK`, `wQ`, `wR`, `wB`, `wN`, `wP`, `bK`, …). The set cannot be changed at runtime; if you need custom piece artwork, fork the package or post-process the generated SVG. ## Usage -### SVG +### SVG -The SVG function is the primary exported function of the package. It writes an SVG document to the io.Writer given. +The `SVG` function is the primary exported function of the package. It writes an SVG document to the `io.Writer` given. Rendering options are configured through an `SVGOptions` value; `nil` or a zero-valued `SVGOptions` uses defaults (white perspective, default square colors, 45px squares, with rank/file coordinates visible). ```go -file, _ := os.Open("output.svg") -defer file.Close() +f, err := os.Create("output.svg") +if err != nil { + log.Fatal(err) +} +defer f.Close() + fenStr := "rnbqkbnr/pppppppp/8/8/3P4/8/PPP1PPPP/RNBQKBNR b KQkq - 0 1" pos := &chess.Position{} -pos.UnmarshalText([]byte(fenStr)) -image.SVG(file, pos.Board()) +if err := pos.UnmarshalText([]byte(fenStr)); err != nil { + log.Fatal(err) +} + +if err := image.SVG(f, pos, nil); err != nil { + log.Fatal(err) +} ``` -### Dark / Light Square Customization +### Square Colors -The default colors, shown in the example SVG below, are (235, 209, 166) for light squares and (165, 117, 81) for dark squares. The light and dark squares can be customized using the SquareColors() option. +The default colors are `color.RGBA{235, 209, 166, 255}` for light squares and `color.RGBA{165, 117, 81, 255}` for dark squares. Both colors are opaque. Set `LightSquare` and `DarkSquare` on `SVGOptions` to customize them. Nil colors fall back to the defaults. ```go -white := color.RGBA{255, 255, 255, 1} -gray := color.RGBA{120, 120, 120, 1} -sqrs := image.SquareColors(white, gray) -image.SVG(file, pos.Board(), sqrs) +white := color.RGBA{255, 255, 255, 255} +gray := color.RGBA{120, 120, 120, 255} + +if err := image.SVG(f, pos, &image.SVGOptions{ + LightSquare: white, + DarkSquare: gray, +}); err != nil { + log.Fatal(err) +} ``` ### Marked Squares -MarkSquares is designed to be used as an optional argument to the SVG function. It marks the given squares with the color. A possible usage includes marking squares of the previous move. +`SVGOptions.Marks` highlights individual squares with a translucent overlay (fixed opacity 0.2; mark color controls hue only). A typical use is marking the squares involved in the previous move. Mark keys outside `A1`..`H8` and nil mark colors are ignored. ```go -yellow := color.RGBA{255, 255, 0, 1} -mark := image.MarkSquares(yellow, chess.D2, chess.D4) -image.SVG(file, pos.Board(), mark) +yellow := color.RGBA{255, 255, 0, 255} +if err := image.SVG(f, pos, &image.SVGOptions{ + Marks: map[chess.Square]color.Color{ + chess.D2: yellow, + chess.D4: yellow, + }, +}); err != nil { + log.Fatal(err) +} ``` ### Perspective -Perspective is designed to be used as an optional argument -to the SVG function. It draws the board from the perspective -of the given color. White is the default. The following -generates a board from Black's perspective: +`SVGOptions.Perspective` selects the orientation of the board. White is the default. Any value other than `chess.Black` falls back to white without error. + +```go +if err := image.SVG(f, pos, &image.SVGOptions{ + Perspective: chess.Black, +}); err != nil { + log.Fatal(err) +} +``` + +### Square Size and Coordinates + +`SquareSize` (in CSS pixels) scales the entire board. The default is 45. The board is always 8x8 squares, so the total SVG width and height are `8 * SquareSize`. A `SquareSize <= 0` falls back to the default. Set `HideCoordinates` to true to omit the rank and file labels. ```go -fromBlack := image.Perspective(chess.Black) -image.SVG(file, pos.Board(), fromBlack) +if err := image.SVG(f, pos, &image.SVGOptions{ + SquareSize: 90, + HideCoordinates: true, +}); err != nil { + log.Fatal(err) +} ``` -### Example Program +### Errors + +`SVG` returns a non-nil error when the writer is nil (`image: nil writer`), when the position is nil or has no board (`image: nil position`), or when an underlying write fails. The first write error is returned unchanged. + +## Example Program ```go package main import ( - "image/color" - "log" - "os" + "image/color" + "log" + "os" - "github.com/corentings/chess" - "github.com/corentings/chess/image" + "github.com/corentings/chess" + "github.com/corentings/chess/image" ) func main() { - // create file - f, err := os.Create("example.svg") + f, err := os.Create("output.svg") if err != nil { log.Fatal(err) } defer f.Close() - // create board position fenStr := "rnbqkbnr/pppppppp/8/8/3P4/8/PPP1PPPP/RNBQKBNR b KQkq - 0 1" pos := &chess.Position{} if err := pos.UnmarshalText([]byte(fenStr)); err != nil { log.Fatal(err) } - // write board SVG to file - yellow := color.RGBA{255, 255, 0, 1} - mark := image.MarkSquares(yellow, chess.D2, chess.D4) - if err := image.SVG(f, pos.Board(), mark); err != nil { + yellow := color.RGBA{255, 255, 0, 255} + if err := image.SVG(f, pos, &image.SVGOptions{ + Marks: map[chess.Square]color.Color{ + chess.D2: yellow, + chess.D4: yellow, + }, + }); err != nil { log.Fatal(err) } } ``` - -### Example Program Result - -![rnbqkbnr/pppppppp/8/8/3P4/8/PPP1PPPP/RNBQKBNR b KQkq - 0 1](example.svg) - diff --git a/image/black_example.svg b/image/black_example.svg deleted file mode 100644 index c6d710f9..00000000 --- a/image/black_example.svg +++ /dev/null @@ -1,534 +0,0 @@ - - - - - - - - - - - - - - - - -1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -2 - - - - - - - - - - - - - - - - - - - - - - - - - - - -3 - - - - - - - - -4 - - - - - - - - - - - - -5 - - - - - - - - -6 - - - - - - - - - - - -7 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -8 -h - - - - - - - - - - -g - - - - - - - - - - - -f - - - - - - - - - - - -e - - - - - - - - - - - - - - - - - - - -d - - - - - - - - - - - -c - - - - - - - - - - -b - - - - - - - - - - - - - - - - -a - \ No newline at end of file diff --git a/image/example.svg b/image/example.svg deleted file mode 100644 index 33149051..00000000 --- a/image/example.svg +++ /dev/null @@ -1,534 +0,0 @@ - - - - - - - - - - - - - - - - - - - - -8 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -7 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -6 - - - - - - - - -5 - - - - - - - - -4 - - - - - - - - - - - - -3 - - - - - - - - - - - -2 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -1 -a - - - - - - - - - -b - - - - - - - - - - - -c - - - - - - - - - - - - - - -d - - - - - - - - - - - - -e - - - - - - - - - - - -f - - - - - - - - - -g - - - - - - - - - - - - -h - \ No newline at end of file diff --git a/image/image.go b/image/image.go old mode 100755 new mode 100644 index b01ca6b7..fe930aab --- a/image/image.go +++ b/image/image.go @@ -1,162 +1,223 @@ -// Package image is a go library that creates images from board positions +// Package image renders chess positions as SVG images. +// +// The package embeds a single piece set in internal/pieces (one SVG per +// color and piece type: wK, wQ, wR, wB, wN, wP, bK, ...). The set is fixed: +// there is no API to swap in a different piece set. To render with custom +// artwork, post-process the SVG or fork the package. package image import ( + "embed" + "errors" "fmt" "image/color" "io" "strings" - svg "github.com/ajstarks/svgo" - "github.com/corentings/chess/v2" - "github.com/corentings/chess/v2/image/internal" + "github.com/corentings/chess/v3" ) -// SVG writes the board SVG representation into the writer. -// An error is returned if there is there is an error writing data. -// SVG also takes options which can customize the image output. -func SVG(w io.Writer, b *chess.Board, opts ...func(*encoder)) error { - e := newEncoder(w, opts) - return e.EncodeSVG(b) +const ( + defaultSquareSize = 45 + markOpacity = "0.2" + pieceBaseSize = 45.0 +) + +var ( + defaultLightSquare = color.RGBA{R: 235, G: 209, B: 166, A: 255} + defaultDarkSquare = color.RGBA{R: 165, G: 117, B: 81, A: 255} + + orderOfRanks = []chess.Rank{chess.Rank8, chess.Rank7, chess.Rank6, chess.Rank5, chess.Rank4, chess.Rank3, chess.Rank2, chess.Rank1} + orderOfRanksBlack = []chess.Rank{chess.Rank1, chess.Rank2, chess.Rank3, chess.Rank4, chess.Rank5, chess.Rank6, chess.Rank7, chess.Rank8} + orderOfFiles = []chess.File{chess.FileA, chess.FileB, chess.FileC, chess.FileD, chess.FileE, chess.FileF, chess.FileG, chess.FileH} + orderOfFilesBlack = []chess.File{chess.FileH, chess.FileG, chess.FileF, chess.FileE, chess.FileD, chess.FileC, chess.FileB, chess.FileA} +) + +//go:embed internal/pieces/*.svg +var piecesFS embed.FS + +var pieceSVGs = loadPieceSVGs() + +// SVGOptions customizes SVG rendering. +// Zero-valued fields use defaults. +type SVGOptions struct { + LightSquare color.Color + DarkSquare color.Color + Marks map[chess.Square]color.Color + Perspective chess.Color + SquareSize int + HideCoordinates bool +} + +type svgOptions struct { + lightSquare color.Color + darkSquare color.Color + marks map[chess.Square]color.Color + perspective chess.Color + squareSize int + hideCoordinates bool } -// SquareColors is designed to be used as an optional argument -// to the SVG function. It changes the default light and -// dark square colors to the colors given. -func SquareColors(light, dark color.Color) func(*encoder) { - return func(e *encoder) { - e.light = light - e.dark = dark +// SVG writes the position SVG representation into the writer. +func SVG(w io.Writer, pos *chess.Position, opts *SVGOptions) error { + if w == nil { + return errors.New("image: nil writer") } + if pos == nil || pos.Board() == nil { + return errors.New("image: nil position") + } + + o := normalizeSVGOptions(opts) + r := &svgRenderer{w: w, opts: o} + r.render(pos) + return r.err } -// MarkSquares is designed to be used as an optional argument -// to the SVG function. It marks the given squares with the -// color. A possible usage includes marking squares of the -// previous move. -func MarkSquares(c color.Color, sqs ...chess.Square) func(*encoder) { - return func(e *encoder) { - for _, sq := range sqs { - e.marks[sq] = c +type svgRenderer struct { + w io.Writer + opts svgOptions + err error +} + +func (r *svgRenderer) render(pos *chess.Position) { + boardSize := r.opts.squareSize * 8 + r.write(`` + "\n") + r.writef(``+"\n", boardSize, boardSize, boardSize, boardSize) + + boardMap := pos.Board().SquareMap() + ranks, files := rankAndFileOrder(r.opts.perspective) + lastRank := len(ranks) - 1 + for i, rank := range ranks { + for j, file := range files { + x := j * r.opts.squareSize + y := i * r.opts.squareSize + sq := chess.NewSquare(file, rank) + r.renderSquare(x, y, sq) + r.renderMark(x, y, sq) + r.renderPiece(x, y, sq, boardMap[sq]) + if !r.opts.hideCoordinates { + r.renderCoordinates(x, y, i, j, lastRank, sq) + } } } + r.write("\n") } -// Perspective is designed to be used as an optional argument -// to the SVG function. It draws the board from the perspective -// of the given color. White is the default. -func Perspective(c chess.Color) func(*encoder) { - return func(e *encoder) { - e.perspective = c +func (r *svgRenderer) renderSquare(x, y int, sq chess.Square) { + squareClass := "light" + fill := r.opts.lightSquare + if isDarkSquare(sq) { + squareClass = "dark" + fill = r.opts.darkSquare } + r.writef(``+"\n", + squareClass, sq.String(), x, y, r.opts.squareSize, r.opts.squareSize, colorToHex(fill)) } -// A Encoder encodes chess boards into images. -type encoder struct { - w io.Writer - light color.Color - dark color.Color - marks map[chess.Square]color.Color - perspective chess.Color +func (r *svgRenderer) renderMark(x, y int, sq chess.Square) { + markColor, ok := r.opts.marks[sq] + if !ok { + return + } + r.writef(``+"\n", + sq.String(), x, y, r.opts.squareSize, r.opts.squareSize, colorToHex(markColor), markOpacity) } -// newEncoder returns an encoder that writes to the given writer. -// newEncoder also takes options which can customize the image -// output. -func newEncoder(w io.Writer, options []func(*encoder)) *encoder { - e := &encoder{ - w: w, - light: color.RGBA{235, 209, 166, 1}, - dark: color.RGBA{165, 117, 81, 1}, - perspective: chess.White, - marks: map[chess.Square]color.Color{}, +func (r *svgRenderer) renderPiece(x, y int, sq chess.Square, p chess.Piece) { + if p == chess.NoPiece { + return + } + inner, ok := pieceSVGs[pieceFileName(p)] + if !ok { + return } - for _, op := range options { - op(e) + r.writef(``+"\n", + pieceColorClass(p.Color()), pieceTypeClass(p.Type()), sq.String(), x, y, scaleString(r.opts.squareSize)) + r.write(inner) + if !strings.HasSuffix(inner, "\n") { + r.write("\n") } - return e + r.write("\n") } -const ( - sqWidth = 45 - sqHeight = 45 - boardWidth = 8 * sqWidth - boardHeight = 8 * sqHeight -) +func (r *svgRenderer) renderCoordinates(x, y, rankIndex, fileIndex, lastRank int, sq chess.Square) { + textColor := r.opts.darkSquare + if isDarkSquare(sq) { + textColor = r.opts.lightSquare + } + fontSize := r.opts.squareSize * 11 / defaultSquareSize + if fontSize < 1 { + fontSize = 1 + } + if fileIndex == 0 { + r.writef(`%s`+"\n", + x+r.opts.squareSize/20, y+r.opts.squareSize*5/20, fontSize, colorToHex(textColor), sq.Rank().String()) + } + if rankIndex == lastRank { + r.writef(`%s`+"\n", + x+r.opts.squareSize*19/20, y+r.opts.squareSize-r.opts.squareSize/15, fontSize, colorToHex(textColor), sq.File().String()) + } +} -var ( - orderOfRanks = []chess.Rank{chess.Rank8, chess.Rank7, chess.Rank6, chess.Rank5, chess.Rank4, chess.Rank3, chess.Rank2, chess.Rank1} - orderOfRanksBlack = []chess.Rank{chess.Rank1, chess.Rank2, chess.Rank3, chess.Rank4, chess.Rank5, chess.Rank6, chess.Rank7, chess.Rank8} - orderOfFiles = []chess.File{chess.FileA, chess.FileB, chess.FileC, chess.FileD, chess.FileE, chess.FileF, chess.FileG, chess.FileH} - orderOfFilesBlack = []chess.File{chess.FileH, chess.FileG, chess.FileF, chess.FileE, chess.FileD, chess.FileC, chess.FileB, chess.FileA} -) +func (r *svgRenderer) write(s string) { + if r.err != nil { + return + } + _, r.err = io.WriteString(r.w, s) +} -// EncodeSVG writes the board SVG representation into -// the Encoder's writer. An error is returned if there -// is there is an error writing data. -func (e *encoder) EncodeSVG(b *chess.Board) error { - const lastRank = 7 - boardMap := b.SquareMap() - canvas := svg.New(e.w) - canvas.Start(boardWidth, boardHeight) - canvas.Rect(0, 0, boardWidth, boardHeight) - - ranks := orderOfRanks - files := orderOfFiles - if e.perspective == chess.Black { - ranks = orderOfRanksBlack - files = orderOfFilesBlack +func (r *svgRenderer) writef(format string, args ...any) { + if r.err != nil { + return } - for i, rank := range ranks { - for j, file := range files { - x := j * sqHeight - y := i * sqHeight - sq := chess.NewSquare(file, rank) - c := e.colorForSquare(sq) - canvas.Rect(x, y, sqWidth, sqHeight, "fill: "+colorToHex(c)) - markColor, ok := e.marks[sq] - if ok { - canvas.Rect(x, y, sqWidth, sqHeight, "fill-opacity:0.2;fill: "+colorToHex(markColor)) - } - // draw piece - p := boardMap[sq] - if p != chess.NoPiece { - xml := pieceXML(x, y, p) - if _, err := io.WriteString(canvas.Writer, xml); err != nil { - return err - } - } - // draw rank text on file A - txtColor := e.colorForText(sq) - if j == 0 { - style := "font-size:11px;fill: " + colorToHex(txtColor) - canvas.Text(x+(sqWidth*1/20), y+(sqHeight*5/20), sq.Rank().String(), style) //nolint:mnd // this is a magic number - } - // draw file text on rank 1 - if i == lastRank { - style := "text-anchor:end;font-size:11px;fill: " + colorToHex(txtColor) - canvas.Text(x+(sqWidth*19/20), y+sqHeight-(sqHeight*1/15), sq.File().String(), style) //nolint:mnd // this is a magic number - } + _, r.err = fmt.Fprintf(r.w, format, args...) +} + +func normalizeSVGOptions(opts *SVGOptions) svgOptions { + o := svgOptions{ + lightSquare: defaultLightSquare, + darkSquare: defaultDarkSquare, + marks: map[chess.Square]color.Color{}, + perspective: chess.White, + squareSize: defaultSquareSize, + } + if opts == nil { + return o + } + if opts.LightSquare != nil { + o.lightSquare = opts.LightSquare + } + if opts.DarkSquare != nil { + o.darkSquare = opts.DarkSquare + } + if opts.Perspective == chess.Black { + o.perspective = chess.Black + } + if opts.SquareSize > 0 { + o.squareSize = opts.SquareSize + } + o.hideCoordinates = opts.HideCoordinates + for sq, c := range opts.Marks { + if isValidSquare(sq) && c != nil { + o.marks[sq] = c } } - canvas.End() - return nil + return o } -func (e *encoder) colorForSquare(sq chess.Square) color.Color { - sqSum := int(sq.File()) + int(sq.Rank()) - if sqSum%2 == 0 { - return e.dark +func rankAndFileOrder(perspective chess.Color) ([]chess.Rank, []chess.File) { + if perspective == chess.Black { + return orderOfRanksBlack, orderOfFilesBlack } - return e.light + return orderOfRanks, orderOfFiles } -func (e *encoder) colorForText(sq chess.Square) color.Color { - sqSum := int(sq.File()) + int(sq.Rank()) - if sqSum%2 == 0 { - return e.light - } - return e.dark +func isValidSquare(sq chess.Square) bool { + return sq >= chess.A1 && sq <= chess.H8 +} + +func isDarkSquare(sq chess.Square) bool { + return (int(sq.File())+int(sq.Rank()))%2 == 0 } func colorToHex(c color.Color) string { @@ -164,12 +225,76 @@ func colorToHex(c color.Color) string { return fmt.Sprintf("#%02x%02x%02x", uint8(r>>8), uint8(g>>8), uint8(b>>8)) } -func pieceXML(x, y int, p chess.Piece) string { - fileName := fmt.Sprintf("pieces/%s%s.svg", p.Color().String(), pieceTypeMap[p.Type()]) - svgStr := internal.MustSVG(fileName) - old := `` - sprintf := fmt.Sprintf(``, -1*x, -1*y) - return strings.Replace(svgStr, old, sprintf, 1) +func loadPieceSVGs() map[string]string { + pieceFiles := []string{ + "internal/pieces/bB.svg", + "internal/pieces/bK.svg", + "internal/pieces/bN.svg", + "internal/pieces/bP.svg", + "internal/pieces/bQ.svg", + "internal/pieces/bR.svg", + "internal/pieces/wB.svg", + "internal/pieces/wK.svg", + "internal/pieces/wN.svg", + "internal/pieces/wP.svg", + "internal/pieces/wQ.svg", + "internal/pieces/wR.svg", + } + svgs := make(map[string]string, len(pieceFiles)) + for _, f := range pieceFiles { + b, err := piecesFS.ReadFile(f) + if err != nil { + panic(fmt.Sprintf("image: failed to read embedded asset %s: %v", f, err)) + } + svgs[f] = innerSVG(f, string(b)) + } + return svgs +} + +func innerSVG(name, svg string) string { + svg = strings.TrimSpace(svg) + if !strings.HasPrefix(svg, "") + end := strings.LastIndex(svg, "") + if start == -1 || end == -1 || end <= start { + panic(fmt.Sprintf("image: malformed embedded asset %s", name)) + } + return strings.TrimSpace(svg[start+1 : end]) +} + +func pieceFileName(p chess.Piece) string { + return fmt.Sprintf("internal/pieces/%s%s.svg", p.Color().String(), pieceTypeMap[p.Type()]) +} + +func pieceColorClass(c chess.Color) string { + if c == chess.Black { + return "black" + } + return "white" +} + +func pieceTypeClass(t chess.PieceType) string { + switch t { + case chess.King: + return "king" + case chess.Queen: + return "queen" + case chess.Rook: + return "rook" + case chess.Bishop: + return "bishop" + case chess.Knight: + return "knight" + case chess.Pawn: + return "pawn" + } + return "piece" +} + +func scaleString(squareSize int) string { + return fmt.Sprintf("%.6g", float64(squareSize)/pieceBaseSize) } var pieceTypeMap = map[chess.PieceType]string{ diff --git a/image/image_test.go b/image/image_test.go old mode 100755 new mode 100644 index 9324b2bf..9135f42c --- a/image/image_test.go +++ b/image/image_test.go @@ -1,83 +1,186 @@ -package image_test +package image import ( "bytes" - "crypto/md5" - "fmt" + "encoding/xml" + "errors" "image/color" "io" - "os" "strings" "testing" - "github.com/corentings/chess/v2" - "github.com/corentings/chess/v2/image" + "github.com/corentings/chess/v3" ) -const ( - expectedMD5 = "08aaa6fcfde3bb900fc54bdfef3d5c81" - expectedMD5Black = "badac5ca5cfbdea9b98a1f9988ba54bc" -) +func TestSVGDefaultRender(t *testing.T) { + svg := renderSVG(t, chess.StartingPosition(), nil) -func TestSVG(t *testing.T) { - // create buffer of actual svg - buf := bytes.NewBuffer([]byte{}) - fenStr := "rnbqkbnr/pppppppp/8/8/3P4/8/PPP1PPPP/RNBQKBNR b KQkq - 0 1" - pos := &chess.Position{} - if err := pos.UnmarshalText([]byte(fenStr)); err != nil { - t.Error(err) + if !strings.HasPrefix(svg, "\n - - - - - - - - - - - - - - - -1 -a - - - - - - - - - -b - - - - - - - - - - - -c - - - - - - - - - - - - - - -d - - - - - - - - - - - - -e - - - - - - - - - - - -f - - - - - - - - - -g - - - - - - - - - - - - -h - - - - -2 - - - - - - - - - - - - - - - - - - - - - - - - - - - -3 - - - - - - - - -4 - - - - - - - - - - - - -5 - - - - - - - - -6 - - - - - - - - - - - -7 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -8 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - diff --git a/legality.go b/legality.go new file mode 100644 index 00000000..6d5c13ac --- /dev/null +++ b/legality.go @@ -0,0 +1,230 @@ +package chess + +import ( + "errors" + "fmt" + "math/bits" +) + +// ErrIllegalMove is returned by resolveCanonicalMove when the supplied +// coordinates do not match any legal move from the given Position. +var ErrIllegalMove = errors.New("chess: illegal move") + +// resolveCanonicalMove validates a caller-supplied Move against the legal +// moves of pos and returns the canonical generated Move with position-derived +// tags (capture, en passant, castling, check). A Null-tagged Move returns +// NewNullMove regardless of origin, destination, or promotion. +// +// The returned Move is what safe insertion should store, encode, and apply: +// its identity (origin, destination, promotion) and its tags both reflect the +// position. A caller who supplied partial or stale tags therefore benefits +// from repair: the Move tree keeps the canonical value, and downstream +// cursor application, repetition detection, and PGN encoding see one +// interpretation. +// +// Errors: +// - ErrIllegalMove if no legal move matches the supplied coordinates. +// - "chess: position required" if pos is nil and the Move is not Null. +func resolveCanonicalMove(pos *Position, m Move) (Move, error) { + if m.HasTag(Null) { + return NewNullMove(), nil + } + if pos == nil { + return Move{}, errors.New("chess: position required") + } + for _, v := range pos.ValidMovesUnsafe() { + if v.s1 == m.s1 && v.s2 == m.s2 && v.promo == m.promo { + return v, nil + } + } + return Move{}, fmt.Errorf("chess: illegal move %s: %w", m.String(), ErrIllegalMove) +} + +// legality owns the king-safety policy for one position. Construct one per +// position with newLegality and call legal on every candidate move. +// +// legality never mutates its pos. The slow path (king moves, en passant, +// in-check, opponent-Check annotation) uses a stack copy of pos.board; the +// prefilter lives in legality.filter for movegen's hot loop. +// +// legal returns (tag, ok). ok is true iff the move leaves the moving side's +// own king safe. tag always carries the cheap bits (Capture/EnPassant/castle); +// in mode == generateLegalAnnotated it also carries Check when applicable. +// Callers must gate on ok before trusting tag for annotation. +type legality struct { + pos *Position + mode moveGenerationMode + enabled bool + checkCount int + checkMask bitboard +} + +func newLegality(pos *Position, mode moveGenerationMode) legality { + lg := legality{pos: pos, mode: mode} + if mode == generateUnsafeOnly { + return lg + } + kingSq := pos.board.kingSquare(pos.turn) + if kingSq == NoSquare { + return lg + } + queenBB, rookBB, bishopBB := sliderBitboards(&pos.board, pos.turn.Other()) + if !pos.inCheck && alignedMasks[kingSq]&(queenBB|rookBB|bishopBB) == 0 { + return lg + } + lg.enabled = true + lg.checkMask = ^bitboard(0) + if pos.inCheck { + setCheckContext(&lg, kingSq, pos.checkers) + } + return lg +} + +// setCheckContext derives the check-count and check-mask from a precomputed +// bitboard of checking pieces. When the position was constructed through the +// normal paths (NewPosition, decodeFENUnsafe, applyMove) pos.checkers is +// already accurate, so this avoids recomputing the full attack set. +func setCheckContext(lg *legality, kingSq Square, checkers bitboard) { + lg.checkCount = bits.OnesCount64(uint64(checkers)) + if lg.checkCount == 1 { + checkerSq := squareFromBit(checkers) + lg.checkMask = bbForSquare(checkerSq) + if squaresAligned(kingSq, checkerSq) { + lg.checkMask |= squaresBetween(kingSq, checkerSq) + } + } +} + +// filter restricts the pseudo-legal destinations for one piece using the +// precomputed king-safety context. King moves and pawns-with-en-passant +// always pass through (they need a per-move legality check); in double check, +// only King moves survive (movegen's non-King loops see s2BB == 0). +func (lg legality) filter(p Piece, s1 Square, moves bitboard) bitboard { + if !lg.enabled { + return moves + } + if p.Type() == King { + return moves + } + if lg.pos.enPassantSquare != NoSquare && p.Type() == Pawn { + return moves + } + if lg.checkCount > 1 { + return 0 + } + if lg.checkCount == 1 { + moves &= lg.checkMask + } + if pinRay := pinnedRayForPiece(lg.pos, s1); pinRay != 0 { + moves &= pinRay + } + return moves +} + +func (lg legality) legal(m Move) (MoveTag, bool) { + var tag MoveTag + p := lg.pos.board.Piece(m.s1) + + if lg.pos.board.isOccupied(m.s2) { + tag |= Capture + } else if m.s2 == lg.pos.enPassantSquare && p.Type() == Pawn { + tag |= EnPassant + } + if p == WhiteKing && m.s1.Rank() == Rank1 { + switch m.s2 { + case G1: + if lg.pos.castleRights.CanCastle(White, KingSide) { + tag |= KingSideCastle + } + case C1: + if lg.pos.castleRights.CanCastle(White, QueenSide) { + tag |= QueenSideCastle + } + } + } else if p == BlackKing && m.s1.Rank() == Rank8 { + switch m.s2 { + case G8: + if lg.pos.castleRights.CanCastle(Black, KingSide) { + tag |= KingSideCastle + } + case C8: + if lg.pos.castleRights.CanCastle(Black, QueenSide) { + tag |= QueenSideCastle + } + } + } + + return lg.kingSafety(m, p, tag) +} + +func (lg legality) kingSafety(m Move, p Piece, tag MoveTag) (MoveTag, bool) { + // Fast path: not in check, not King, not en passant. Positions without + // aligned enemy slider pressure skip the slider check entirely. + if !lg.pos.inCheck && p.Type() != King && tag&EnPassant == 0 { + if moveFromAlignedWithOwnKing(m, lg.pos) && exposesOwnKingToSlider(m, lg.pos) { + return tag, false + } + if lg.mode == generateLegalAnnotated { + return lg.annotateCheck(m, tag), true + } + return tag, true + } + return lg.simulate(m, tag) +} + +func (lg legality) annotateCheck(m Move, tag MoveTag) MoveTag { + b := lg.pos.board + applied := m + applied.tags = tag + b.update(applied, computeMoveEffect(&lg.pos.board, applied)) + if b.kingSquare(lg.pos.turn.Other()) != NoSquare && + isSquareAttackedBy(&b, b.kingSquare(lg.pos.turn.Other()), lg.pos.turn) { + tag |= Check + } + return tag +} + +func (lg legality) simulate(m Move, tag MoveTag) (MoveTag, bool) { + // Direct b.update on a stack copy: simulate only needs piece placement + // for the attack test; applyMove's scalar state (moveCount, hash, + // castleRights, EP) must not change on the live position. + b := lg.pos.board + applied := m + applied.tags = tag + b.update(applied, computeMoveEffect(&lg.pos.board, applied)) + if b.kingSquare(lg.pos.turn) != NoSquare && + isSquareAttackedBy(&b, b.kingSquare(lg.pos.turn), lg.pos.turn.Other()) { + return tag, false + } + if lg.mode == generateLegalAnnotated { + if b.kingSquare(lg.pos.turn.Other()) != NoSquare && + isSquareAttackedBy(&b, b.kingSquare(lg.pos.turn.Other()), lg.pos.turn) { + tag |= Check + } + } + return tag, true +} + +func moveFromAlignedWithOwnKing(m Move, pos *Position) bool { + kingSq := pos.board.kingSquare(pos.turn) + if kingSq == NoSquare { + return false + } + return alignedMasks[kingSq]&bbForSquare(m.s1) != 0 +} + +func exposesOwnKingToSlider(m Move, pos *Position) bool { + kingSq := pos.board.kingSquare(pos.turn) + if kingSq == NoSquare { + return false + } + occ := (^pos.board.emptySqs &^ bbForSquare(m.s1)) | bbForSquare(m.s2) + attacker := pos.turn.Other() + captured := bbForSquare(m.s2) + queenBB, rookBB, bishopBB := sliderBitboards(&pos.board, attacker) + queenBB &^= captured + rookBB &^= captured + bishopBB &^= captured + return hvAttack(occ, kingSq)&(queenBB|rookBB) != 0 || + diaAttack(occ, kingSq)&(queenBB|bishopBB) != 0 +} diff --git a/legality_test.go b/legality_test.go new file mode 100644 index 00000000..c9d89e67 --- /dev/null +++ b/legality_test.go @@ -0,0 +1,152 @@ +package chess + +import "testing" + +// TestLegalityPinnedPiece pins a queen to the king on the same file as a +// rook: a move off the pin file exposes the king. +func TestLegalityPinnedPiece(t *testing.T) { + // White king on e1, white queen on e4, black rook on e8. The queen + // blocks the rook's attack on the e-file. Moving the queen off the + // file exposes the king to the rook; capturing the rook is legal. + pos := mustPosition(t, "4r2k/8/8/8/4Q3/8/8/4K3 w - - 0 1") + + lg := newLegality(pos, generateLegalAnnotated) + + mOff := Move{s1: E4, s2: D4} + if _, ok := lg.legal(mOff); ok { + t.Errorf("queen off the pin file must be illegal, got legal") + } + + mCapture := Move{s1: E4, s2: E8} + tag, ok := lg.legal(mCapture) + if !ok { + t.Errorf("queen capturing the pinning rook must be legal, got illegal") + } + if tag&Capture == 0 { + t.Errorf("queen capturing the pinning rook must carry the Capture tag, got tag=%b", tag) + } +} + +// TestLegalitySingleCheck covers the "capture or step out of check" rule +// when the side to move is in single check. +func TestLegalitySingleCheck(t *testing.T) { + // White king on e1 in single check from black rook on e2. The king can + // capture the checker (e2 not defended by the black king on e8), and + // can step to d1 or f1 (off the rook's rank/file). d2 and f2 lie on + // the rook's rank-2 attack and must be rejected. + pos := mustPosition(t, "4k3/8/8/8/8/8/4r3/4K3 w - - 0 1") + + lg := newLegality(pos, generateLegalAnnotated) + + cases := []struct { + name string + move Move + want bool + }{ + {"capture the checker", Move{s1: E1, s2: E2}, true}, + {"step out to d1", Move{s1: E1, s2: D1}, true}, + {"step out to f1", Move{s1: E1, s2: F1}, true}, + {"step into rook's rank (d2)", Move{s1: E1, s2: D2}, false}, + {"step into rook's rank (f2)", Move{s1: E1, s2: F2}, false}, + } + for _, tc := range cases { + t.Run(tc.name, func(t *testing.T) { + _, ok := lg.legal(tc.move) + if ok != tc.want { + t.Errorf("legal(%s) ok=%v, want %v", tc.move, ok, tc.want) + } + }) + } +} + +// TestLegalityDoubleCheck restricts non-King moves in a double check. +func TestLegalityDoubleCheck(t *testing.T) { + // White king on e1 in double check from a knight on c2 and a rook on e8. + // No single interposition can block both — only king moves are legal. + pos := mustPosition(t, "4r2k/8/8/8/8/8/2nP4/4K3 w - - 0 1") + + lg := newLegality(pos, generateLegalOnly) + + mKing := Move{s1: E1, s2: D1} + if _, ok := lg.legal(mKing); !ok { + t.Errorf("king move in double check must be legal, got illegal") + } + + // A pawn push cannot resolve either checker; it must be rejected. + mPawn := Move{s1: D2, s2: D3} + if _, ok := lg.legal(mPawn); ok { + t.Errorf("non-king move in double check must be illegal, got legal") + } +} + +// TestLegalityEnPassantDiscoveredCheck: a pawn en passant capture that +// opens a discovered check on the moving side's king must be illegal. +func TestLegalityEnPassantDiscoveredCheck(t *testing.T) { + // White king on h5, white pawn on f5, black pawn on g5 (just moved from + // g7-g5, giving EP target g6), black rook on a5. Before the move the + // f5 pawn shields the king from the rook along rank 5. En-passant + // f5xg6 removes BOTH the f5 pawn (moves to g6) and the g5 pawn (captured), + // opening rank 5 and exposing the king to the rook. + pos := mustPosition(t, "7k/8/8/r4PpK/8/8/8/8 w - g6 0 1") + + lg := newLegality(pos, generateLegalAnnotated) + + mEP := Move{s1: F5, s2: G6} + _, ok := lg.legal(mEP) + if ok { + t.Errorf("en passant that exposes own king must be illegal, got legal") + } +} + +// TestLegalityAnnotatesCheck covers the generateLegalAnnotated mode: +// legal moves that give check carry the Check tag. +func TestLegalityAnnotatesCheck(t *testing.T) { + // White queen on d5 with a clear line to the black king on h5; the + // Qd5-h5 diagonal has no blockers. + pos := mustPosition(t, "7k/8/8/3Q4/8/8/8/K7 w - - 0 1") + + lg := newLegality(pos, generateLegalAnnotated) + + mCheck := Move{s1: D5, s2: H5} + tag, ok := lg.legal(mCheck) + if !ok { + t.Errorf("Qd5-h5 must be legal, got illegal") + } + if tag&Check == 0 { + t.Errorf("Qd5-h5 must carry the Check tag, got tag=%b", tag) + } +} + +// TestLegalityNotMutable guards the "legality never mutates its pos" contract +// from legality.go:10. Catches the failure mode where simulate or +// annotateCheck is rerouted through applyMove or a pos.board pointer alias +// and silently corrupts scalar state on the live position. +func TestLegalityNotMutable(t *testing.T) { + pos := mustPosition(t, "4k3/8/8/8/8/8/4r3/4K3 w - - 0 1") + before := pos.moveCount + pos.hash = 0xDEAD + pos.halfMoveClock = 7 + pos.castleRights = NewCastleRights(true, true, false, false) + pos.enPassantSquare = E3 + + lg := newLegality(pos, generateLegalAnnotated) + _, _ = lg.legal(Move{s1: E1, s2: E2}) + _, _ = lg.legal(Move{s1: E1, s2: D1}) + + if pos.moveCount != before { + t.Errorf("legality mutated pos.moveCount: got %d, want %d", pos.moveCount, before) + } + if pos.hash != 0xDEAD { + t.Errorf("legality mutated pos.hash: got %#x, want 0xDEAD", pos.hash) + } + if pos.halfMoveClock != 7 { + t.Errorf("legality mutated pos.halfMoveClock: got %d, want 7", pos.halfMoveClock) + } + want := NewCastleRights(true, true, false, false) + if pos.castleRights != want { + t.Errorf("legality mutated pos.castleRights: got %q, want %q", pos.castleRights, want) + } + if pos.enPassantSquare != E3 { + t.Errorf("legality mutated pos.enPassantSquare: got %v, want E3", pos.enPassantSquare) + } +} diff --git a/lexer.go b/lexer.go index 9eab1a09..14c2ccc3 100644 --- a/lexer.go +++ b/lexer.go @@ -61,6 +61,7 @@ const ( CommandParam // Command parameter CommandEnd // ] DeambiguationSquare // Full square disambiguation (e.g., e8 in Qe8f7) + NullMove // A null move: Z0, Z1, --, or @@ ) func (t TokenType) String() string { @@ -96,6 +97,8 @@ func (t TokenType) String() string { "CommandName", "CommandParam", "CommandEnd", + "DeambiguationSquare", + "NullMove", } if t < 0 || int(t) >= len(types) { @@ -207,19 +210,18 @@ func (l *Lexer) readCommandParam() Token { } func (l *Lexer) readNAG() Token { - // Handle cases where NAG starts with '!' or '?' - // This shouldn't happen from my understanding of the PGN spec but lichess pgn files have it. - // TODO: Better NAG handling of different formats + // Handle cases where NAG starts with '!' or '?' (symbolic move-quality + // spellings such as ! ? !! ?? !? ?!). This isn't part of the strict PGN + // spec, but Lichess and other sources emit them, so they are accepted on + // import. The lexer reads the maximal run of '!' and '?' characters as a + // single token; normalisation to the canonical "$N" form happens at the + // storage boundary (see ParseNAG). if l.ch == '!' || l.ch == '?' { - value := string(l.ch) - l.readChar() // Read the next character - - // Check if the next character is also '!' or '?' - if l.ch == '!' || l.ch == '?' { - value += string(l.ch) // Append the second character - l.readChar() // Move to the next character + position := l.position + for l.ch == '!' || l.ch == '?' { + l.readChar() } - + value := l.input[position:l.position] return Token{Type: NAG, Value: value} } l.readChar() // skip the $ symbol @@ -250,7 +252,7 @@ func (l *Lexer) readResult() Token { } func (l *Lexer) readRank() Token { - rank := string(l.ch) + rank := l.input[l.position : l.position+1] if !isRank(l.ch) { l.readChar() return Token{Type: RANK, Error: ErrInvalidRank(l.position), Value: rank} @@ -264,10 +266,15 @@ func (l *Lexer) readComment() Token { // Look for command start sequence for l.ch != '}' && l.ch != 0 { + if l.ch == '\\' && l.peekChar() == '}' { + l.readChar() + l.readChar() + continue + } if l.ch == '[' && l.peekChar() == '%' { if position != l.position { // Return accumulated comment text before the command - return Token{Type: COMMENT, Value: strings.TrimSpace(l.input[position:l.position])} + return Token{Type: COMMENT, Value: cleanCommentText(l.input[position:l.position])} } // Start command processing l.readChar() // skip [ @@ -296,16 +303,21 @@ func (l *Lexer) readComment() Token { // Return remaining comment text if any if position != l.position { - return Token{Type: COMMENT, Value: strings.TrimSpace(l.input[position:l.position])} + return Token{Type: COMMENT, Value: cleanCommentText(l.input[position:l.position])} } return Token{Type: CommentEnd, Value: "}"} } +func cleanCommentText(text string) string { + text = strings.TrimSpace(text) + return strings.ReplaceAll(text, `\}`, "}") +} + // Update readPieceMove to handle piece moves. func (l *Lexer) readPieceMove() Token { // Capture just the piece - piece := string(l.ch) + piece := l.input[l.position : l.position+1] if !isPiece(l.ch) { l.readChar() return Token{Type: PIECE, Error: ErrInvalidPiece(l.position), Value: piece} @@ -329,7 +341,7 @@ func (l *Lexer) readMove() Token { // For pawn captures if isFile(l.ch) { - file := string(l.ch) + file := l.input[l.position : l.position+1] l.readChar() // Check for capture @@ -375,7 +387,7 @@ func (l *Lexer) readMove() Token { l.readPosition = position + 1 l.readChar() // Return just the first character as disambiguation - return Token{Type: FILE, Value: string(l.input[position])} + return Token{Type: FILE, Value: l.input[position : position+1]} } // Validate the square (e.g., "e4") @@ -388,7 +400,7 @@ func (l *Lexer) readMove() Token { } func (l *Lexer) readPromotionPiece() Token { - piece := string(l.ch) + piece := l.input[l.position : l.position+1] if !isPiece(l.ch) { l.readChar() return Token{Type: PromotionPiece, Error: ErrInvalidPiece(l.position), Value: piece} @@ -409,7 +421,18 @@ func (l *Lexer) readChar() { func (l *Lexer) readTagValue() Token { l.readChar() // skip opening quote + position := l.position + for l.ch != '"' && l.ch != '\\' && l.ch != 0 { + l.readChar() + } + if l.ch != '\\' { + value := l.input[position:l.position] + l.readChar() // skip closing quote + return Token{Type: TagValue, Value: value} + } + var value strings.Builder + value.WriteString(l.input[position:l.position]) for l.ch != '"' && l.ch != 0 { if l.ch == '\\' { next := l.peekChar() @@ -468,10 +491,68 @@ func (l *Lexer) readCastling() (Token, bool) { if l.ch == '-' && l.peekChar() == 'O' { l.readChar() // skip - l.readChar() // skip O - return Token{Type: QueensideCastle, Value: "O-O-O"}, true + return Token{Type: QueensideCastle, Value: castleQS}, true } - return Token{Type: KingsideCastle, Value: "O-O"}, true + return Token{Type: KingsideCastle, Value: castleKS}, true +} + +// readNullMove consumes a null-move token at the current position and returns +// it. Recognised spellings: "Z0", "Z1", "--", "@@", "0000". Returns (Token{}, false) +// if the current character does not start a null-move token. Safe to call from +// NextToken before the main dispatch because it never clashes with valid move +// squares, piece letters, or result tokens. +func (l *Lexer) readNullMove() (Token, bool) { + switch l.ch { + case 'Z': + next := l.peekChar() + if next != '0' && next != '1' { + return Token{}, false + } + position := l.position + l.readChar() + l.readChar() + return Token{Type: NullMove, Value: l.input[position:l.position]}, true + + case '-': + if l.peekChar() != '-' { + return Token{}, false + } + // Standalone "--" — readResult already consumed any result token + // beginning with a digit ("1-0", "0-1", "1/2-1/2"), and readCastling + // requires an uppercase O, so we cannot be inside those. + l.readChar() + l.readChar() + return Token{Type: NullMove, Value: "--"}, true + + case '@': + if l.peekChar() != '@' { + return Token{}, false + } + l.readChar() + l.readChar() + return Token{Type: NullMove, Value: "@@"}, true + + case '0': + // "0000" — must be four zeros with nothing digit/dash-adjacent to + // avoid clashing with result/castle tokens. readCastling consumes + // "O-O" / "O-O-O" and readResult consumes "1-0" / "0-1" before we + // reach here, so standalone "0000" can safely be claimed. + if l.position+3 >= len(l.input) { + return Token{}, false + } + if l.input[l.position+1] != '0' || + l.input[l.position+2] != '0' || + l.input[l.position+3] != '0' { + return Token{}, false + } + l.readChar() + l.readChar() + l.readChar() + l.readChar() + return Token{Type: NullMove, Value: "0000"}, true + } + return Token{}, false } // NextToken reads the next token from the input stream. @@ -527,6 +608,12 @@ func (l *Lexer) NextToken() Token { return l.readTagKey() } + // Null move tokens: "Z0", "Z1" (ChessBase / Scid), "--" (pgn-extract, + // Scid), "@@" (some exporters), and "0000" (UCI convention). + if tok, ok := l.readNullMove(); ok { + return tok + } + switch l.ch { case '(': l.readChar() @@ -611,6 +698,15 @@ func (l *Lexer) NextToken() Token { l.ch = l.input[position] return l.readResult() default: + // "1/2-1/2" draw result token, e.g. "1. e4 e5 1/2-1/2". The digit + // run stopped at '/'; if the literal pattern starts at the run + // start, reset and let readResult consume and validate it. + if position+7 <= len(l.input) && l.input[position:position+7] == Draw.String() { + l.position = position + l.readPosition = position + 1 + l.ch = l.input[position] + return l.readResult() + } // Reset position and try again as a regular number l.position = position l.readPosition = position + 1 @@ -632,7 +728,7 @@ func (l *Lexer) NextToken() Token { } } - tok := Token{Type: Undefined, Value: string(l.ch)} + tok := Token{Type: Undefined, Value: l.input[l.position : l.position+1]} l.readChar() return tok } diff --git a/lexer_test.go b/lexer_test.go index 629aa75d..f41bd7da 100644 --- a/lexer_test.go +++ b/lexer_test.go @@ -1,11 +1,13 @@ -package chess +package chess_test import ( "os" "testing" + + "github.com/corentings/chess/v3" ) -func TestLexer(t *testing.T) { +func TestLexer_TokenizesFullGame(t *testing.T) { input := `[Event "Example"] [Site "Internet"] [Date "2023.12.06"] @@ -16,60 +18,60 @@ func TestLexer(t *testing.T) { 1. e4 e5 2. Nf3 Nc6 3. Bb5 {This is the Ruy Lopez.} 3... a6 1-0` - lexer := NewLexer(input) + lexer := chess.NewLexer(input) expectedTokens := []struct { - typ TokenType + typ chess.TokenType value string }{ - {TagStart, "["}, - {TagKey, "Event"}, - {TagValue, "Example"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Site"}, - {TagValue, "Internet"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Date"}, - {TagValue, "2023.12.06"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Round"}, - {TagValue, "1"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "White"}, - {TagValue, "Player1"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Black"}, - {TagValue, "Player2"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Result"}, - {TagValue, "1-0"}, - {TagEnd, "]"}, - {MoveNumber, "1"}, - {DOT, "."}, - {SQUARE, "e4"}, - {SQUARE, "e5"}, - {MoveNumber, "2"}, - {DOT, "."}, - {PIECE, "N"}, - {SQUARE, "f3"}, - {PIECE, "N"}, - {SQUARE, "c6"}, - {MoveNumber, "3"}, - {DOT, "."}, - {PIECE, "B"}, - {SQUARE, "b5"}, - {CommentStart, "{"}, - {COMMENT, "This is the Ruy Lopez."}, - {CommentEnd, "}"}, - {MoveNumber, "3"}, - {ELLIPSIS, "..."}, - {SQUARE, "a6"}, - {RESULT, "1-0"}, + {chess.TagStart, "["}, + {chess.TagKey, "Event"}, + {chess.TagValue, "Example"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Site"}, + {chess.TagValue, "Internet"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Date"}, + {chess.TagValue, "2023.12.06"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Round"}, + {chess.TagValue, "1"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "White"}, + {chess.TagValue, "Player1"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Black"}, + {chess.TagValue, "Player2"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Result"}, + {chess.TagValue, "1-0"}, + {chess.TagEnd, "]"}, + {chess.MoveNumber, "1"}, + {chess.DOT, "."}, + {chess.SQUARE, "e4"}, + {chess.SQUARE, "e5"}, + {chess.MoveNumber, "2"}, + {chess.DOT, "."}, + {chess.PIECE, "N"}, + {chess.SQUARE, "f3"}, + {chess.PIECE, "N"}, + {chess.SQUARE, "c6"}, + {chess.MoveNumber, "3"}, + {chess.DOT, "."}, + {chess.PIECE, "B"}, + {chess.SQUARE, "b5"}, + {chess.CommentStart, "{"}, + {chess.COMMENT, "This is the Ruy Lopez."}, + {chess.CommentEnd, "}"}, + {chess.MoveNumber, "3"}, + {chess.ELLIPSIS, "..."}, + {chess.SQUARE, "a6"}, + {chess.RESULT, "1-0"}, } for i, expected := range expectedTokens { @@ -82,23 +84,23 @@ func TestLexer(t *testing.T) { // Test EOF token := lexer.NextToken() - if token.Type != EOF { + if token.Type != chess.EOF { t.Errorf("Expected EOF token, got %v", token.Type) } } -func Test_TagKey(t *testing.T) { +func TestLexer_ParsesTagValueWithApostrophe(t *testing.T) { input := "[Opening \"King's Indian Attack, General\"]" - lexer := NewLexer(input) + lexer := chess.NewLexer(input) expectedTokens := []struct { - typ TokenType + typ chess.TokenType value string }{ - {TagStart, "["}, - {TagKey, "Opening"}, - {TagValue, "King's Indian Attack, General"}, - {TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Opening"}, + {chess.TagValue, "King's Indian Attack, General"}, + {chess.TagEnd, "]"}, } for i, expected := range expectedTokens { @@ -110,102 +112,44 @@ func Test_TagKey(t *testing.T) { } } -func TestCheck(t *testing.T) { - tests := []struct { - name string - input string - expected []Token - }{ - { - name: "Check", - input: "e5+", - expected: []Token{ - {Type: SQUARE, Value: "e5"}, - {Type: CHECK, Value: "+"}, - }, - }, - { - name: "Checkmate", - input: "e5#", - expected: []Token{ - {Type: SQUARE, Value: "e5"}, - {Type: CHECKMATE, Value: "#"}, - }, - }, - } - - for _, tt := range tests { - t.Run(tt.name, func(t *testing.T) { - lexer := NewLexer(tt.input) - - for i, expected := range tt.expected { - token := lexer.NextToken() - if token.Type != expected.Type || token.Value != expected.Value { - t.Errorf("Token %d - Expected {%v, %q}, got {%v, %q}", - i, expected.Type, expected.Value, token.Type, token.Value) - } - } +func TestLexer_ParsesTagValueWithEscapedBackslash(t *testing.T) { + lexer := chess.NewLexer(`[Path "C:\\Games"]`) + lexer.NextToken() + lexer.NextToken() - // Verify we get EOF after all tokens - token := lexer.NextToken() - if token.Type != EOF { - t.Errorf("Expected EOF token after capture, got %v", token.Type) - } - }) + token := lexer.NextToken() + if token.Type != chess.TagValue || token.Value != `C:\Games` { + t.Fatalf("TagValue = {%v, %q}, want {%v, %q}", token.Type, token.Value, chess.TagValue, `C:\Games`) } } -func TestDisambiguation(t *testing.T) { +func TestLexer_CheckAndCheckmateSuffixes(t *testing.T) { tests := []struct { name string input string - expected []Token + expected []chess.Token }{ { - name: "Disambiguation by file", - input: "Nbd7", - expected: []Token{ - {Type: PIECE, Value: "N"}, - {Type: FILE, Value: "b"}, - {Type: SQUARE, Value: "d7"}, - }, - }, - { - name: "Disambiguation by rank", - input: "N4d7", - expected: []Token{ - {Type: PIECE, Value: "N"}, - {Type: RANK, Value: "4"}, - {Type: SQUARE, Value: "d7"}, + name: "Check", + input: "e5+", + expected: []chess.Token{ + {Type: chess.SQUARE, Value: "e5"}, + {Type: chess.CHECK, Value: "+"}, }, }, - { - name: "Disambiguation in game", - input: "1. e4 e5 2. Nf3 Nc6 3. Nbd7", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e4"}, - {Type: SQUARE, Value: "e5"}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "f3"}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "c6"}, - {Type: MoveNumber, Value: "3"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: FILE, Value: "b"}, - {Type: SQUARE, Value: "d7"}, + name: "Checkmate", + input: "e5#", + expected: []chess.Token{ + {Type: chess.SQUARE, Value: "e5"}, + {Type: chess.CHECKMATE, Value: "#"}, }, }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { - lexer := NewLexer(tt.input) + lexer := chess.NewLexer(tt.input) for i, expected := range tt.expected { token := lexer.NextToken() @@ -217,54 +161,54 @@ func TestDisambiguation(t *testing.T) { // Verify we get EOF after all tokens token := lexer.NextToken() - if token.Type != EOF { - t.Errorf("Expected EOF token after capture, got %v", token.Type) + if token.Type != chess.EOF { + t.Errorf("expected EOF after sequence, got %v", token.Type) } }) } } -func TestPromotion(t *testing.T) { +func TestLexer_Promotion(t *testing.T) { tests := []struct { name string input string - expected []Token + expected []chess.Token }{ { name: "Promotion", input: "e8=Q", - expected: []Token{ - {Type: SQUARE, Value: "e8"}, - {Type: PROMOTION, Value: "="}, - {Type: PromotionPiece, Value: "Q"}, + expected: []chess.Token{ + {Type: chess.SQUARE, Value: "e8"}, + {Type: chess.PROMOTION, Value: "="}, + {Type: chess.PromotionPiece, Value: "Q"}, }, }, { name: "Promotion in game", input: "1. e8=Q e1=N 2. exd8=R", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e8"}, - {Type: PROMOTION, Value: "="}, - {Type: PromotionPiece, Value: "Q"}, - {Type: SQUARE, Value: "e1"}, - {Type: PROMOTION, Value: "="}, - {Type: PromotionPiece, Value: "N"}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: FILE, Value: "e"}, - {Type: CAPTURE, Value: "x"}, - {Type: SQUARE, Value: "d8"}, - {Type: PROMOTION, Value: "="}, - {Type: PromotionPiece, Value: "R"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e8"}, + {Type: chess.PROMOTION, Value: "="}, + {Type: chess.PromotionPiece, Value: "Q"}, + {Type: chess.SQUARE, Value: "e1"}, + {Type: chess.PROMOTION, Value: "="}, + {Type: chess.PromotionPiece, Value: "N"}, + {Type: chess.MoveNumber, Value: "2"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.FILE, Value: "e"}, + {Type: chess.CAPTURE, Value: "x"}, + {Type: chess.SQUARE, Value: "d8"}, + {Type: chess.PROMOTION, Value: "="}, + {Type: chess.PromotionPiece, Value: "R"}, }, }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { - lexer := NewLexer(tt.input) + lexer := chess.NewLexer(tt.input) for i, expected := range tt.expected { token := lexer.NextToken() @@ -276,95 +220,95 @@ func TestPromotion(t *testing.T) { // Verify we get EOF after all tokens token := lexer.NextToken() - if token.Type != EOF { - t.Errorf("Expected EOF token after capture, got %v", token.Type) + if token.Type != chess.EOF { + t.Errorf("expected EOF after sequence, got %v", token.Type) } }) } } -func TestNAG(t *testing.T) { +func TestLexer_NAG(t *testing.T) { tests := []struct { name string input string - expected []Token + expected []chess.Token }{ { name: "NAG", input: "e5 $1", - expected: []Token{ - {Type: SQUARE, Value: "e5"}, - {Type: NAG, Value: "$1"}, + expected: []chess.Token{ + {Type: chess.SQUARE, Value: "e5"}, + {Type: chess.NAG, Value: "$1"}, }, }, { name: "NAG in game", input: "1. e5 $1 e6 $2 2. Nf3 $3", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e5"}, - {Type: NAG, Value: "$1"}, - {Type: SQUARE, Value: "e6"}, - {Type: NAG, Value: "$2"}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "f3"}, - {Type: NAG, Value: "$3"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e5"}, + {Type: chess.NAG, Value: "$1"}, + {Type: chess.SQUARE, Value: "e6"}, + {Type: chess.NAG, Value: "$2"}, + {Type: chess.MoveNumber, Value: "2"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "f3"}, + {Type: chess.NAG, Value: "$3"}, }, }, { name: "NAG and comment after move", input: "e4 $1 {Good move}", - expected: []Token{ - {Type: SQUARE, Value: "e4"}, - {Type: NAG, Value: "$1"}, - {Type: CommentStart, Value: "{"}, - {Type: COMMENT, Value: "Good move"}, - {Type: CommentEnd, Value: "}"}, + expected: []chess.Token{ + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.NAG, Value: "$1"}, + {Type: chess.CommentStart, Value: "{"}, + {Type: chess.COMMENT, Value: "Good move"}, + {Type: chess.CommentEnd, Value: "}"}, }, }, { name: "Comment and NAG after move", input: "e4 {Good move} $1", - expected: []Token{ - {Type: SQUARE, Value: "e4"}, - {Type: CommentStart, Value: "{"}, - {Type: COMMENT, Value: "Good move"}, - {Type: CommentEnd, Value: "}"}, - {Type: NAG, Value: "$1"}, + expected: []chess.Token{ + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.CommentStart, Value: "{"}, + {Type: chess.COMMENT, Value: "Good move"}, + {Type: chess.CommentEnd, Value: "}"}, + {Type: chess.NAG, Value: "$1"}, }, }, { name: "Move with multiple NAGs and comment", input: "e4 $1 $2 {Excellent move}", - expected: []Token{ - {Type: SQUARE, Value: "e4"}, - {Type: NAG, Value: "$1"}, - {Type: NAG, Value: "$2"}, - {Type: CommentStart, Value: "{"}, - {Type: COMMENT, Value: "Excellent move"}, - {Type: CommentEnd, Value: "}"}, + expected: []chess.Token{ + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.NAG, Value: "$1"}, + {Type: chess.NAG, Value: "$2"}, + {Type: chess.CommentStart, Value: "{"}, + {Type: chess.COMMENT, Value: "Excellent move"}, + {Type: chess.CommentEnd, Value: "}"}, }, }, { name: "Move with comment and multiple NAGs", input: "e4 {Excellent move} $1 $2", - expected: []Token{ - {Type: SQUARE, Value: "e4"}, - {Type: CommentStart, Value: "{"}, - {Type: COMMENT, Value: "Excellent move"}, - {Type: CommentEnd, Value: "}"}, - {Type: NAG, Value: "$1"}, - {Type: NAG, Value: "$2"}, + expected: []chess.Token{ + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.CommentStart, Value: "{"}, + {Type: chess.COMMENT, Value: "Excellent move"}, + {Type: chess.CommentEnd, Value: "}"}, + {Type: chess.NAG, Value: "$1"}, + {Type: chess.NAG, Value: "$2"}, }, }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { - lexer := NewLexer(tt.input) + lexer := chess.NewLexer(tt.input) for i, expected := range tt.expected { token := lexer.NextToken() @@ -376,84 +320,84 @@ func TestNAG(t *testing.T) { // Verify we get EOF after all tokens token := lexer.NextToken() - if token.Type != EOF { - t.Errorf("Expected EOF token after capture, got %v", token.Type) + if token.Type != chess.EOF { + t.Errorf("expected EOF after sequence, got %v", token.Type) } }) } } -func TestCaptures(t *testing.T) { +func TestLexer_Captures(t *testing.T) { tests := []struct { name string input string - expected []Token + expected []chess.Token }{ { name: "Pawn capture", input: "exf3", - expected: []Token{ - {Type: FILE, Value: "e"}, - {Type: CAPTURE, Value: "x"}, - {Type: SQUARE, Value: "f3"}, + expected: []chess.Token{ + {Type: chess.FILE, Value: "e"}, + {Type: chess.CAPTURE, Value: "x"}, + {Type: chess.SQUARE, Value: "f3"}, }, }, { name: "Piece capture", input: "Nxc6", - expected: []Token{ - {Type: PIECE, Value: "N"}, - {Type: CAPTURE, Value: "x"}, - {Type: SQUARE, Value: "c6"}, + expected: []chess.Token{ + {Type: chess.PIECE, Value: "N"}, + {Type: chess.CAPTURE, Value: "x"}, + {Type: chess.SQUARE, Value: "c6"}, }, }, { name: "Piece capture with file disambiguation", input: "Nbxc6", - expected: []Token{ - {Type: PIECE, Value: "N"}, - {Type: FILE, Value: "b"}, - {Type: CAPTURE, Value: "x"}, - {Type: SQUARE, Value: "c6"}, + expected: []chess.Token{ + {Type: chess.PIECE, Value: "N"}, + {Type: chess.FILE, Value: "b"}, + {Type: chess.CAPTURE, Value: "x"}, + {Type: chess.SQUARE, Value: "c6"}, }, }, { name: "Piece capture with rank disambiguation", input: "N4xd5", - expected: []Token{ - {Type: PIECE, Value: "N"}, - {Type: RANK, Value: "4"}, - {Type: CAPTURE, Value: "x"}, - {Type: SQUARE, Value: "d5"}, + expected: []chess.Token{ + {Type: chess.PIECE, Value: "N"}, + {Type: chess.RANK, Value: "4"}, + {Type: chess.CAPTURE, Value: "x"}, + {Type: chess.SQUARE, Value: "d5"}, }, }, { name: "Complex position with captures", input: "1. e4 d5 2. Nf3 Nc6 3. Nbxd5", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e4"}, - {Type: SQUARE, Value: "d5"}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "f3"}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "c6"}, - {Type: MoveNumber, Value: "3"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: FILE, Value: "b"}, - {Type: CAPTURE, Value: "x"}, - {Type: SQUARE, Value: "d5"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.SQUARE, Value: "d5"}, + {Type: chess.MoveNumber, Value: "2"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "f3"}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "c6"}, + {Type: chess.MoveNumber, Value: "3"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.FILE, Value: "b"}, + {Type: chess.CAPTURE, Value: "x"}, + {Type: chess.SQUARE, Value: "d5"}, }, }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { - lexer := NewLexer(tt.input) + lexer := chess.NewLexer(tt.input) for i, expected := range tt.expected { token := lexer.NextToken() @@ -465,44 +409,44 @@ func TestCaptures(t *testing.T) { // Verify we get EOF after all tokens token := lexer.NextToken() - if token.Type != EOF { - t.Errorf("Expected EOF token after capture, got %v", token.Type) + if token.Type != chess.EOF { + t.Errorf("expected EOF after sequence, got %v", token.Type) } }) } } // Test captures in context -func TestCapturesInGame(t *testing.T) { +func TestLexer_CapturesInGameContext(t *testing.T) { input := "1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6" expectedTokens := []struct { - typ TokenType + typ chess.TokenType value string }{ - {MoveNumber, "1"}, - {DOT, "."}, - {SQUARE, "e4"}, - {SQUARE, "e5"}, - {MoveNumber, "2"}, - {DOT, "."}, - {PIECE, "N"}, - {SQUARE, "f3"}, - {PIECE, "N"}, - {SQUARE, "c6"}, - {MoveNumber, "3"}, - {DOT, "."}, - {PIECE, "B"}, - {SQUARE, "b5"}, - {SQUARE, "a6"}, - {MoveNumber, "4"}, - {DOT, "."}, - {PIECE, "B"}, - {CAPTURE, "x"}, - {SQUARE, "c6"}, + {chess.MoveNumber, "1"}, + {chess.DOT, "."}, + {chess.SQUARE, "e4"}, + {chess.SQUARE, "e5"}, + {chess.MoveNumber, "2"}, + {chess.DOT, "."}, + {chess.PIECE, "N"}, + {chess.SQUARE, "f3"}, + {chess.PIECE, "N"}, + {chess.SQUARE, "c6"}, + {chess.MoveNumber, "3"}, + {chess.DOT, "."}, + {chess.PIECE, "B"}, + {chess.SQUARE, "b5"}, + {chess.SQUARE, "a6"}, + {chess.MoveNumber, "4"}, + {chess.DOT, "."}, + {chess.PIECE, "B"}, + {chess.CAPTURE, "x"}, + {chess.SQUARE, "c6"}, } - lexer := NewLexer(input) + lexer := chess.NewLexer(input) for i, expected := range expectedTokens { token := lexer.NextToken() @@ -513,76 +457,76 @@ func TestCapturesInGame(t *testing.T) { } } -func TestCommands(t *testing.T) { +func TestLexer_Commands(t *testing.T) { tests := []struct { name string input string - expected []Token + expected []chess.Token }{ { name: "Command", input: "{[%clk 12:34:56]}", - expected: []Token{ - {Type: CommentStart, Value: "{"}, - {Type: CommandStart, Value: "[%"}, - {Type: CommandName, Value: "clk"}, - {Type: CommandParam, Value: "12:34:56"}, - {Type: CommandEnd, Value: "]"}, - {Type: CommentEnd, Value: "}"}, + expected: []chess.Token{ + {Type: chess.CommentStart, Value: "{"}, + {Type: chess.CommandStart, Value: "[%"}, + {Type: chess.CommandName, Value: "clk"}, + {Type: chess.CommandParam, Value: "12:34:56"}, + {Type: chess.CommandEnd, Value: "]"}, + {Type: chess.CommentEnd, Value: "}"}, }, }, { name: "Command in game", input: "1. e4 {[%clk 12:34:56]} e5", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e4"}, - {Type: CommentStart, Value: "{"}, - {Type: CommandStart, Value: "[%"}, - {Type: CommandName, Value: "clk"}, - {Type: CommandParam, Value: "12:34:56"}, - {Type: CommandEnd, Value: "]"}, - {Type: CommentEnd, Value: "}"}, - {Type: SQUARE, Value: "e5"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.CommentStart, Value: "{"}, + {Type: chess.CommandStart, Value: "[%"}, + {Type: chess.CommandName, Value: "clk"}, + {Type: chess.CommandParam, Value: "12:34:56"}, + {Type: chess.CommandEnd, Value: "]"}, + {Type: chess.CommentEnd, Value: "}"}, + {Type: chess.SQUARE, Value: "e5"}, }, }, { // Test multiple commands name: "Multiple commands", input: "{[%clk 0:00:07][%eval -6.05] White is toast}", - expected: []Token{ - {Type: CommentStart, Value: "{"}, - {Type: CommandStart, Value: "[%"}, - {Type: CommandName, Value: "clk"}, - {Type: CommandParam, Value: "0:00:07"}, - {Type: CommandEnd, Value: "]"}, - {Type: CommandStart, Value: "[%"}, - {Type: CommandName, Value: "eval"}, - {Type: CommandParam, Value: "-6.05"}, - {Type: CommandEnd, Value: "]"}, - {Type: COMMENT, Value: "White is toast"}, - {Type: CommentEnd, Value: "}"}, + expected: []chess.Token{ + {Type: chess.CommentStart, Value: "{"}, + {Type: chess.CommandStart, Value: "[%"}, + {Type: chess.CommandName, Value: "clk"}, + {Type: chess.CommandParam, Value: "0:00:07"}, + {Type: chess.CommandEnd, Value: "]"}, + {Type: chess.CommandStart, Value: "[%"}, + {Type: chess.CommandName, Value: "eval"}, + {Type: chess.CommandParam, Value: "-6.05"}, + {Type: chess.CommandEnd, Value: "]"}, + {Type: chess.COMMENT, Value: "White is toast"}, + {Type: chess.CommentEnd, Value: "}"}, }, }, { name: "Command with multiple parameters", input: "{[%command 1:45:12,Nf6,\"very interesting, but wrong\"]}", - expected: []Token{ - {Type: CommentStart, Value: "{"}, - {Type: CommandStart, Value: "[%"}, - {Type: CommandName, Value: "command"}, - {Type: CommandParam, Value: "1:45:12"}, - {Type: CommandParam, Value: "Nf6"}, - {Type: CommandParam, Value: "very interesting, but wrong"}, - {Type: CommandEnd, Value: "]"}, - {Type: CommentEnd, Value: "}"}, + expected: []chess.Token{ + {Type: chess.CommentStart, Value: "{"}, + {Type: chess.CommandStart, Value: "[%"}, + {Type: chess.CommandName, Value: "command"}, + {Type: chess.CommandParam, Value: "1:45:12"}, + {Type: chess.CommandParam, Value: "Nf6"}, + {Type: chess.CommandParam, Value: "very interesting, but wrong"}, + {Type: chess.CommandEnd, Value: "]"}, + {Type: chess.CommentEnd, Value: "}"}, }, }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { - lexer := NewLexer(tt.input) + lexer := chess.NewLexer(tt.input) for i, expected := range tt.expected { token := lexer.NextToken() @@ -594,112 +538,112 @@ func TestCommands(t *testing.T) { // Verify we get EOF after all tokens token := lexer.NextToken() - if token.Type != EOF { - t.Errorf("Expected EOF token after capture, got %v", token.Type) + if token.Type != chess.EOF { + t.Errorf("expected EOF after sequence, got %v", token.Type) } }) } } -func TestVariations(t *testing.T) { +func TestLexer_Variations(t *testing.T) { tests := []struct { name string input string - expected []Token + expected []chess.Token }{ { name: "Variation start", input: "1. e4 (1. d4) e5", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e4"}, - {Type: VariationStart, Value: "("}, - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "d4"}, - {Type: VariationEnd, Value: ")"}, - {Type: SQUARE, Value: "e5"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.VariationStart, Value: "("}, + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "d4"}, + {Type: chess.VariationEnd, Value: ")"}, + {Type: chess.SQUARE, Value: "e5"}, }, }, { name: "Variation in game", input: "1. e4 (1. d4) e5 2. Nf3 (2. Nc3) Nc6", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e4"}, - {Type: VariationStart, Value: "("}, - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "d4"}, - {Type: VariationEnd, Value: ")"}, - {Type: SQUARE, Value: "e5"}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "f3"}, - {Type: VariationStart, Value: "("}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "c3"}, - {Type: VariationEnd, Value: ")"}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "c6"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.VariationStart, Value: "("}, + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "d4"}, + {Type: chess.VariationEnd, Value: ")"}, + {Type: chess.SQUARE, Value: "e5"}, + {Type: chess.MoveNumber, Value: "2"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "f3"}, + {Type: chess.VariationStart, Value: "("}, + {Type: chess.MoveNumber, Value: "2"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "c3"}, + {Type: chess.VariationEnd, Value: ")"}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "c6"}, }, }, { name: "Nested variations", input: "1. e4 (1. d4 (1. c4)) 1... e5", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e4"}, - {Type: VariationStart, Value: "("}, - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "d4"}, - {Type: VariationStart, Value: "("}, - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "c4"}, - {Type: VariationEnd, Value: ")"}, - {Type: VariationEnd, Value: ")"}, - {Type: MoveNumber, Value: "1"}, - {Type: ELLIPSIS, Value: "..."}, - {Type: SQUARE, Value: "e5"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.VariationStart, Value: "("}, + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "d4"}, + {Type: chess.VariationStart, Value: "("}, + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "c4"}, + {Type: chess.VariationEnd, Value: ")"}, + {Type: chess.VariationEnd, Value: ")"}, + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.ELLIPSIS, Value: "..."}, + {Type: chess.SQUARE, Value: "e5"}, }, }, { name: "Another variation", input: "1. e4 e5 (1... e6 2. d4 d5) 2. Nf3", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e4"}, - {Type: SQUARE, Value: "e5"}, - {Type: VariationStart, Value: "("}, - {Type: MoveNumber, Value: "1"}, - {Type: ELLIPSIS, Value: "..."}, - {Type: SQUARE, Value: "e6"}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "d4"}, - {Type: SQUARE, Value: "d5"}, - {Type: VariationEnd, Value: ")"}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "f3"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.SQUARE, Value: "e5"}, + {Type: chess.VariationStart, Value: "("}, + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.ELLIPSIS, Value: "..."}, + {Type: chess.SQUARE, Value: "e6"}, + {Type: chess.MoveNumber, Value: "2"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "d4"}, + {Type: chess.SQUARE, Value: "d5"}, + {Type: chess.VariationEnd, Value: ")"}, + {Type: chess.MoveNumber, Value: "2"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "f3"}, }, }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { - lexer := NewLexer(tt.input) + lexer := chess.NewLexer(tt.input) for i, expected := range tt.expected { token := lexer.NextToken() @@ -711,87 +655,87 @@ func TestVariations(t *testing.T) { // Verify we get EOF after all tokens token := lexer.NextToken() - if token.Type != EOF { - t.Errorf("Expected EOF token after capture, got %v", token.Type) + if token.Type != chess.EOF { + t.Errorf("expected EOF after sequence, got %v", token.Type) } }) } } -func TestCaslting(t *testing.T) { +func TestLexer_Castling(t *testing.T) { tests := []struct { name string input string - expected []Token + expected []chess.Token }{ { name: "Short castle", input: "O-O", - expected: []Token{ - {Type: KingsideCastle, Value: "O-O"}, + expected: []chess.Token{ + {Type: chess.KingsideCastle, Value: "O-O"}, }, }, { name: "Long castle", input: "O-O-O", - expected: []Token{ - {Type: QueensideCastle, Value: "O-O-O"}, + expected: []chess.Token{ + {Type: chess.QueensideCastle, Value: "O-O-O"}, }, }, { name: "Short castle in game", input: "1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. O-O", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e4"}, - {Type: SQUARE, Value: "e5"}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "f3"}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "c6"}, - {Type: MoveNumber, Value: "3"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "B"}, - {Type: SQUARE, Value: "c4"}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "f6"}, - {Type: MoveNumber, Value: "4"}, - {Type: DOT, Value: "."}, - {Type: KingsideCastle, Value: "O-O"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.SQUARE, Value: "e5"}, + {Type: chess.MoveNumber, Value: "2"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "f3"}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "c6"}, + {Type: chess.MoveNumber, Value: "3"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "B"}, + {Type: chess.SQUARE, Value: "c4"}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "f6"}, + {Type: chess.MoveNumber, Value: "4"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.KingsideCastle, Value: "O-O"}, }, }, { name: "Long castle in game", input: "1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. O-O-O", - expected: []Token{ - {Type: MoveNumber, Value: "1"}, - {Type: DOT, Value: "."}, - {Type: SQUARE, Value: "e4"}, - {Type: SQUARE, Value: "e5"}, - {Type: MoveNumber, Value: "2"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "f3"}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "c6"}, - {Type: MoveNumber, Value: "3"}, - {Type: DOT, Value: "."}, - {Type: PIECE, Value: "B"}, - {Type: SQUARE, Value: "c4"}, - {Type: PIECE, Value: "N"}, - {Type: SQUARE, Value: "f6"}, - {Type: MoveNumber, Value: "4"}, - {Type: DOT, Value: "."}, - {Type: QueensideCastle, Value: "O-O-O"}, + expected: []chess.Token{ + {Type: chess.MoveNumber, Value: "1"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.SQUARE, Value: "e5"}, + {Type: chess.MoveNumber, Value: "2"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "f3"}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "c6"}, + {Type: chess.MoveNumber, Value: "3"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.PIECE, Value: "B"}, + {Type: chess.SQUARE, Value: "c4"}, + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "f6"}, + {Type: chess.MoveNumber, Value: "4"}, + {Type: chess.DOT, Value: "."}, + {Type: chess.QueensideCastle, Value: "O-O-O"}, }, }, } for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { - lexer := NewLexer(tt.input) + lexer := chess.NewLexer(tt.input) for i, expected := range tt.expected { token := lexer.NextToken() @@ -803,100 +747,36 @@ func TestCaslting(t *testing.T) { // Verify we get EOF after all tokens token := lexer.NextToken() - if token.Type != EOF { - t.Errorf("Expected EOF token after capture, got %v", token.Type) + if token.Type != chess.EOF { + t.Errorf("expected EOF after sequence, got %v", token.Type) } }) } } -func TestFuzzRepro_b41648629adb0a5d_y(t *testing.T) { - input := "y" - lexer := NewLexer(input) - - var tokens []Token - for { - token := lexer.NextToken() - tokens = append(tokens, token) - - if token.Type == EOF { - break - } - - if len(tokens) > len(input)*2 { // Arbitrary limit based on input length - t.Errorf("Too many tokens generated for input length") - break - } - } -} - -func TestFuzzRepro_ff9f899cf2252ff1_a(t *testing.T) { - input := "a" - lexer := NewLexer(input) - - var tokens []Token - defer func() { - if r := recover(); r != nil { - t.Errorf("Lexer panicked on input %q: %v", input, r) - } - }() - for { - token := lexer.NextToken() - tokens = append(tokens, token) - - if token.Type == EOF { - break - } - - if len(tokens) > len(input)*2 { // Arbitrary limit based on input length - t.Errorf("Too many tokens generated for input length") - break - } - } -} - -func TestFuzzRepro_167803a88524c396(t *testing.T) { - input := "{[%0" - lexer := NewLexer(input) - - var tokens []Token - for { - token := lexer.NextToken() - tokens = append(tokens, token) - - if token.Type == EOF { - break - } - - if len(tokens) > len(input)*2 { // Arbitrary limit based on input length - t.Errorf("Too many tokens generated for input length") - break - } - } -} - -func TestFuzzRepro_b68c42fa4236bdd7(t *testing.T) { - input := "{[%,\"" - lexer := NewLexer(input) - - var tokens []Token - defer func() { - if r := recover(); r != nil { - t.Errorf("Lexer panicked on input %q: %v", input, r) - } - }() - for { - token := lexer.NextToken() - tokens = append(tokens, token) - - if token.Type == EOF { - break - } - - if len(tokens) > len(input)*2 { // Arbitrary limit based on input length - t.Errorf("Too many tokens generated for input length") - break - } +func TestFuzzRegressions(t *testing.T) { + seeds := []string{"y", "a", "{[%0", "{[%,\""} + for _, input := range seeds { + t.Run(input, func(t *testing.T) { + lexer := chess.NewLexer(input) + defer func() { + if r := recover(); r != nil { + t.Errorf("Lexer panicked on input %q: %v", input, r) + } + }() + count := 0 + for { + token := lexer.NextToken() + count++ + if token.Type == chess.EOF { + break + } + if count > len(input)*3 { + t.Errorf("Too many tokens generated for input %q", input) + break + } + } + }) } } @@ -964,8 +844,8 @@ func FuzzLexer(f *testing.F) { } }() - lexer := NewLexer(input) - var tokens []Token + lexer := chess.NewLexer(input) + var tokens []chess.Token t.Log("Input:", input) @@ -975,7 +855,7 @@ func FuzzLexer(f *testing.F) { tokens = append(tokens, token) // Stop at EOF - if token.Type == EOF { + if token.Type == chess.EOF { break } @@ -992,132 +872,132 @@ func FuzzLexer(f *testing.F) { }) } -func validateTokens(t *testing.T, tokens []Token) { +func validateTokens(t *testing.T, tokens []chess.Token) { for i, token := range tokens { // Validate specific token values switch token.Type { - case FILE: + case chess.FILE: if len(token.Value) != 1 || token.Value[0] < 'a' || token.Value[0] > 'h' { t.Errorf("Invalid file at token %d: %v", i, token.Value) } - case RANK: - if len(token.Value) != 1 || (!isRank(token.Value[0]) && token.Error == nil) { + case chess.RANK: + if len(token.Value) != 1 || (!(token.Value[0] >= '1' && token.Value[0] <= '8') && token.Error == nil) { t.Errorf("Invalid rank at token %d: %v", i, token.Value) } - case PIECE: - if len(token.Value) != 1 || (!isPiece(token.Value[0]) && token.Error == nil) { + case chess.PIECE: + if len(token.Value) != 1 || (!(token.Value[0] == 'N' || token.Value[0] == 'B' || token.Value[0] == 'R' || token.Value[0] == 'Q' || token.Value[0] == 'K') && token.Error == nil) { t.Errorf("Invalid piece at token %d: %v", i, token.Value) } - case PromotionPiece: - if len(token.Value) != 1 || (!isPiece(token.Value[0]) && token.Error == nil) { + case chess.PromotionPiece: + if len(token.Value) != 1 || (!(token.Value[0] == 'N' || token.Value[0] == 'B' || token.Value[0] == 'R' || token.Value[0] == 'Q' || token.Value[0] == 'K') && token.Error == nil) { t.Errorf("Invalid promotion piece at token %d: %v", i, token.Value) } } } } -func TestSingleFromPosPGN(t *testing.T) { +func TestLexer_FromPositionFixture(t *testing.T) { // Read fixture data, err := os.ReadFile("fixtures/pgns/single_frompos.pgn") if err != nil { t.Fatalf("Failed to read fixture: %v", err) } - lexer := NewLexer(string(data)) + lexer := chess.NewLexer(string(data)) expected := []struct { - typ TokenType + typ chess.TokenType value string }{ // Tags - {TagStart, "["}, - {TagKey, "Event"}, - {TagValue, "Slav Defense: Chebanenko Variation, 5. cxd5"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Site"}, - {TagValue, ""}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Date"}, - {TagValue, "2025.07.12"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Round"}, - {TagValue, "1"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "White"}, - {TagValue, ""}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Black"}, - {TagValue, ""}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Result"}, - {TagValue, "*"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "UTCDate"}, - {TagValue, "2025.07.12"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "UTCTime"}, - {TagValue, "15:51:01"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Variant"}, - {TagValue, "Standard"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "ECO"}, - {TagValue, "D15"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "FEN"}, - {TagValue, "rnbqkb1r/1p2pppp/p1p2n2/3p4/2PP4/2N2N2/PP2PPPP/R1BQKB1R w KQkq - 0 5"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "SetUp"}, - {TagValue, "1"}, - {TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Event"}, + {chess.TagValue, "Slav Defense: Chebanenko Variation, 5. cxd5"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Site"}, + {chess.TagValue, ""}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Date"}, + {chess.TagValue, "2025.07.12"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Round"}, + {chess.TagValue, "1"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "White"}, + {chess.TagValue, ""}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Black"}, + {chess.TagValue, ""}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Result"}, + {chess.TagValue, "*"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "UTCDate"}, + {chess.TagValue, "2025.07.12"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "UTCTime"}, + {chess.TagValue, "15:51:01"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "Variant"}, + {chess.TagValue, "Standard"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "ECO"}, + {chess.TagValue, "D15"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "FEN"}, + {chess.TagValue, "rnbqkb1r/1p2pppp/p1p2n2/3p4/2PP4/2N2N2/PP2PPPP/R1BQKB1R w KQkq - 0 5"}, + {chess.TagEnd, "]"}, + {chess.TagStart, "["}, + {chess.TagKey, "SetUp"}, + {chess.TagValue, "1"}, + {chess.TagEnd, "]"}, // Moves - {MoveNumber, "5"}, - {DOT, "."}, - {FILE, "c"}, - {CAPTURE, "x"}, - {SQUARE, "d5"}, - {VariationStart, "("}, - {MoveNumber, "5"}, - {DOT, "."}, - {SQUARE, "e3"}, - {SQUARE, "e6"}, - {MoveNumber, "6"}, - {DOT, "."}, - {FILE, "c"}, - {CAPTURE, "x"}, - {SQUARE, "d5"}, - {FILE, "c"}, - {CAPTURE, "x"}, - {SQUARE, "d5"}, - {VariationEnd, ")"}, - {MoveNumber, "5"}, - {ELLIPSIS, "..."}, - {FILE, "c"}, - {CAPTURE, "x"}, - {SQUARE, "d5"}, - {MoveNumber, "6"}, - {DOT, "."}, - {SQUARE, "e3"}, - {SQUARE, "e6"}, - {CommentStart, "{"}, - {CommandStart, "[%"}, - {CommandName, "eval"}, - {CommandParam, "0.11"}, - {CommandEnd, "]"}, - {CommentEnd, "}"}, - {RESULT, "*"}, + {chess.MoveNumber, "5"}, + {chess.DOT, "."}, + {chess.FILE, "c"}, + {chess.CAPTURE, "x"}, + {chess.SQUARE, "d5"}, + {chess.VariationStart, "("}, + {chess.MoveNumber, "5"}, + {chess.DOT, "."}, + {chess.SQUARE, "e3"}, + {chess.SQUARE, "e6"}, + {chess.MoveNumber, "6"}, + {chess.DOT, "."}, + {chess.FILE, "c"}, + {chess.CAPTURE, "x"}, + {chess.SQUARE, "d5"}, + {chess.FILE, "c"}, + {chess.CAPTURE, "x"}, + {chess.SQUARE, "d5"}, + {chess.VariationEnd, ")"}, + {chess.MoveNumber, "5"}, + {chess.ELLIPSIS, "..."}, + {chess.FILE, "c"}, + {chess.CAPTURE, "x"}, + {chess.SQUARE, "d5"}, + {chess.MoveNumber, "6"}, + {chess.DOT, "."}, + {chess.SQUARE, "e3"}, + {chess.SQUARE, "e6"}, + {chess.CommentStart, "{"}, + {chess.CommandStart, "[%"}, + {chess.CommandName, "eval"}, + {chess.CommandParam, "0.11"}, + {chess.CommandEnd, "]"}, + {chess.CommentEnd, "}"}, + {chess.RESULT, "*"}, } for i, exp := range expected { @@ -1128,7 +1008,179 @@ func TestSingleFromPosPGN(t *testing.T) { } } // final EOF - if tok := lexer.NextToken(); tok.Type != EOF { + if tok := lexer.NextToken(); tok.Type != chess.EOF { t.Errorf("Expected EOF, got %v", tok.Type) } } + +func assertTokenSequence(t *testing.T, l *chess.Lexer, expected []chess.Token) { + t.Helper() + for i, exp := range expected { + tok := l.NextToken() + if tok.Type != exp.Type || tok.Value != exp.Value { + t.Errorf("Token %d: expected {%v, %q}, got {%v, %q}", + i, exp.Type, exp.Value, tok.Type, tok.Value) + } + if exp.Error != nil && tok.Error == nil { + t.Errorf("Token %d: expected error %q, got nil", i, exp.Error) + } + } + if tok := l.NextToken(); tok.Type != chess.EOF { + t.Errorf("expected EOF after sequence, got {%v, %q}", tok.Type, tok.Value) + } +} + +func TestLexer_EmptyInput(t *testing.T) { + for _, in := range []string{"", " ", " \t\n "} { + l := chess.NewLexer(in) + tok := l.NextToken() + if tok.Type != chess.EOF { + t.Errorf("NewLexer(%q).NextToken() = %v, want EOF", in, tok.Type) + } + } +} + +func TestLexer_UndefinedToken(t *testing.T) { + for _, in := range []string{"@", ";", "~"} { + l := chess.NewLexer(in) + tok := l.NextToken() + if tok.Type != chess.Undefined || tok.Value != in { + t.Errorf("NewLexer(%q).NextToken() = {%v, %q}, want {Undefined, %q}", in, tok.Type, tok.Value, in) + } + if eof := l.NextToken(); eof.Type != chess.EOF { + t.Errorf("expected EOF after undefined, got %v", eof.Type) + } + } +} + +func TestLexer_DeambiguationSquare(t *testing.T) { + tests := []struct { + name string + input string + want []chess.Token + }{ + {"full_square", "Qe8f7", []chess.Token{ + {Type: chess.PIECE, Value: "Q"}, + {Type: chess.DeambiguationSquare, Value: "e8"}, + {Type: chess.SQUARE, Value: "f7"}, + }}, + {"full_square_capture", "Qg8xg7", []chess.Token{ + {Type: chess.PIECE, Value: "Q"}, + {Type: chess.DeambiguationSquare, Value: "g8"}, + {Type: chess.CAPTURE, Value: "x"}, + {Type: chess.SQUARE, Value: "g7"}, + }}, + {"file_only", "Nbd7", []chess.Token{ + {Type: chess.PIECE, Value: "N"}, + {Type: chess.FILE, Value: "b"}, + {Type: chess.SQUARE, Value: "d7"}, + }}, + {"rank_only", "N4d7", []chess.Token{ + {Type: chess.PIECE, Value: "N"}, + {Type: chess.RANK, Value: "4"}, + {Type: chess.SQUARE, Value: "d7"}, + }}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + assertTokenSequence(t, chess.NewLexer(tt.input), tt.want) + }) + } +} + +func TestLexer_ResultSpellings(t *testing.T) { + tests := []struct { + name string + input string + want []chess.Token + }{ + {"white_wins", "1-0", []chess.Token{{Type: chess.RESULT, Value: "1-0"}}}, + {"black_wins", "0-1", []chess.Token{{Type: chess.RESULT, Value: "0-1"}}}, + {"ongoing", "*", []chess.Token{{Type: chess.RESULT, Value: "*"}}}, + {"draw", "1/2-1/2", []chess.Token{ + {Type: chess.RESULT, Value: "1/2-1/2"}, + }}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + assertTokenSequence(t, chess.NewLexer(tt.input), tt.want) + }) + } +} + +func TestLexer_NAGSymbols(t *testing.T) { + tests := []struct { + name string + input string + want []chess.Token + }{ + {"double_bang", "e4!!", []chess.Token{ + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.NAG, Value: "!!"}, + }}, + {"bang", "e4!", []chess.Token{ + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.NAG, Value: "!"}, + }}, + {"question", "e4?", []chess.Token{ + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.NAG, Value: "?"}, + }}, + {"dubious", "e4?!", []chess.Token{ + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.NAG, Value: "?!"}, + }}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + assertTokenSequence(t, chess.NewLexer(tt.input), tt.want) + }) + } +} + +func TestLexer_NAGMaximalRun(t *testing.T) { + // A run of more than two '!'/'?' characters must be a single NAG token, + // not split into a valid token plus a trailing symbol (regression for the + // "!!!" bug that produced two NAG tokens). + assertTokenSequence(t, chess.NewLexer("e4!!!"), []chess.Token{ + {Type: chess.SQUARE, Value: "e4"}, + {Type: chess.NAG, Value: "!!!"}, + }) +} + +func TestLexer_ErrorPaths(t *testing.T) { + tests := []struct { + name string + input string + wantMsg string + }{ + {"unterminated_comment", "{unterm", "unterminated comment"}, + {"unterminated_quote", `{[%clk "12:34]}`, "unterminated quote"}, + {"invalid_command", `{[%clk }]`, "invalid command in comment"}, + {"invalid_piece", "Ze4", "invalid piece"}, + {"invalid_square", "z9", "invalid square"}, + {"invalid_rank", "N9", "invalid rank"}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + l := chess.NewLexer(tt.input) + var errToken chess.Token + for { + tok := l.NextToken() + if tok.Error != nil { + errToken = tok + break + } + if tok.Type == chess.EOF { + t.Fatalf("reached EOF without an error token for input %q", tt.input) + } + } + if errToken.Error == nil { + t.Fatalf("expected error for input %q, got nil", tt.input) + } + if errToken.Error.Error() != tt.wantMsg { + t.Errorf("error = %q, want %q", errToken.Error.Error(), tt.wantMsg) + } + }) + } +} diff --git a/magic.go b/magic.go new file mode 100644 index 00000000..715b109b --- /dev/null +++ b/magic.go @@ -0,0 +1,243 @@ +package chess + +import ( + "math/bits" +) + +// diaAttack returns a bitboard representing possible diagonal moves for a +// sliding piece, considering occupied squares as blocking further movement. +// +// Implementation: index a deterministic magic-bitboard table generated at +// package init from checked-in magic constants. +func diaAttack(occupied bitboard, sq Square) bitboard { + return bishopMagicAttacks[sq][((occupied&bishopMagicMasks[sq])*bishopMagics[sq])>>bishopMagicShifts[sq]] +} + +func slowDiaAttack(occupied bitboard, sq Square) bitboard { + f := int(sq) & 7 + r := int(sq) >> 3 + occ := uint64(occupied) + var attacks uint64 + // NE: rank+1, file+1 (NE-SW diagonal = bbDiagonals[sq]). + for d := 1; f+d < 8 && r+d < 8; d++ { + bit := uint64(1) << (63 - ((r + d) << 3) - (f + d)) + attacks |= bit + if occ&bit != 0 { + break + } + } + // SW: rank-1, file-1 (NE-SW diagonal, opposite side). + for d := 1; f-d >= 0 && r-d >= 0; d++ { + bit := uint64(1) << (63 - ((r - d) << 3) - (f - d)) + attacks |= bit + if occ&bit != 0 { + break + } + } + // NW: rank+1, file-1 (NW-SE diagonal = bbAntiDiagonals[sq]). + for d := 1; f-d >= 0 && r+d < 8; d++ { + bit := uint64(1) << (63 - ((r + d) << 3) - (f - d)) + attacks |= bit + if occ&bit != 0 { + break + } + } + // SE: rank-1, file+1 (NW-SE diagonal, opposite side). + for d := 1; f+d < 8 && r-d >= 0; d++ { + bit := uint64(1) << (63 - ((r - d) << 3) - (f + d)) + attacks |= bit + if occ&bit != 0 { + break + } + } + return bitboard(attacks) +} + +// hvAttack returns a bitboard representing possible horizontal and vertical +// moves for a sliding piece, considering occupied squares as blocking +// further movement. +// +// Implementation: index a deterministic magic-bitboard table generated at +// package init from checked-in magic constants. +func hvAttack(occupied bitboard, sq Square) bitboard { + return rookMagicAttacks[sq][((occupied&rookMagicMasks[sq])*rookMagics[sq])>>rookMagicShifts[sq]] +} + +func slowHVAttack(occupied bitboard, sq Square) bitboard { + f := int(sq) & 7 + r := int(sq) >> 3 + occ := uint64(occupied) + var attacks uint64 + // E: file+1. + for df := 1; f+df < 8; df++ { + bit := uint64(1) << (63 - (r << 3) - (f + df)) + attacks |= bit + if occ&bit != 0 { + break + } + } + // W: file-1. + for df := 1; f-df >= 0; df++ { + bit := uint64(1) << (63 - (r << 3) - (f - df)) + attacks |= bit + if occ&bit != 0 { + break + } + } + // N: rank+1. + for dr := 1; r+dr < 8; dr++ { + bit := uint64(1) << (63 - ((r + dr) << 3) - f) + attacks |= bit + if occ&bit != 0 { + break + } + } + // S: rank-1. + for dr := 1; r-dr >= 0; dr++ { + bit := uint64(1) << (63 - ((r - dr) << 3) - f) + attacks |= bit + if occ&bit != 0 { + break + } + } + return bitboard(attacks) +} + +var ( + rookMagicMasks = [64]bitboard{} + bishopMagicMasks = [64]bitboard{} + rookMagicShifts = [64]uint{} + bishopMagicShifts = [64]uint{} + rookMagicAttacks = [64][4096]bitboard{} + bishopMagicAttacks = [64][512]bitboard{} +) + +// Deterministically generated for this package's A1=MSB square numbering. +var rookMagics = [64]bitboard{ //nolint:gochecknoglobals // lookup constants + 0x000009284d008402, 0x0602004108040082, 0x5262005024880102, 0x071200141020086a, + 0x4003008620500009, 0x0000220010088042, 0x4001004000208015, 0x3620120880410022, + 0x02804d0280542200, 0x80c0081001020400, 0x2058044010200801, 0x4108004200040040, + 0x00a0080050008180, 0x0818220080401200, 0x8000220045028600, 0x40800020014000c0, + 0x4080009408420005, 0x0000080210040001, 0x88c1002400090002, 0x0809001008010004, + 0x00100a0010420020, 0x102c100020008080, 0x003000200040c008, 0x4080004020014000, + 0x010010984200011c, 0x1800010204001008, 0x101200540a000830, 0x0020800800800400, + 0x0100100023000900, 0x0022002042001084, 0x0060200042401008, 0x4000400020800080, + 0x0028012200004084, 0x3900611400d01802, 0x0202000404001020, 0x0002002200100408, + 0x3080080080100080, 0x8000200080801000, 0x0000200280400084, 0x0450288080004000, + 0x000202000c205181, 0x00222c000e100108, 0x8031080110400420, 0x0048008008800400, + 0x0002020020081041, 0x1020018061801000, 0x0010024000200040, 0x2080004000402000, + 0x9182000102046484, 0x0000800200010080, 0x0083000300080400, 0x082a002030048a00, + 0x2181001000090020, 0x0401801000200180, 0x3200404000201000, 0x0000802080004006, + 0x0200048114002042, 0x0200430406002088, 0x2200211028020024, 0x4100080010020500, + 0x0a80080004100082, 0x2700200031000840, 0x0040001000200041, 0x0080006015804008, +} + +var bishopMagics = [64]bitboard{ //nolint:gochecknoglobals // lookup constants + 0x0002100142040242, 0x0000400841140080, 0x2030e04064084220, 0x000120813092020a, + 0x0510c0040020a800, 0x0000810104010400, 0x0400078084100260, 0x0480808808020200, + 0x1284040842042000, 0x0221a00400808021, 0x4000068850010010, 0x0a10001020222022, + 0x6802124842020062, 0x8050002084100106, 0x6222092108020020, 0x4a2c012188600001, + 0x4408880100400020, 0x10421e0204004212, 0x006210b000804100, 0x1410401011010210, + 0x0800044200908800, 0x0000104828007000, 0x1004210108041001, 0x60009004200210c0, + 0x10a408a482082400, 0x0008081120009082, 0x0802208104020040, 0x0084200200082080, + 0x0100020080080080, 0x4142045101900100, 0x0022022023900100, 0x4002034080200812, + 0x04a2048008540081, 0x4004088530421004, 0x8268080800808400, 0x0000848014002000, + 0x800c080100220040, 0x0000208224080080, 0x0008208004091244, 0x0428400420024a81, + 0x0081020a00420204, 0x5002011080b0880a, 0x10f2001040422080, 0x0044004480a02000, + 0x0008000420401100, 0x0784026088001240, 0x0202040810210200, 0x2021120420420220, + 0xe000422508088400, 0x000001008820880a, 0x4006011048040004, 0x0008020210008000, + 0x8000040408800821, 0x8016048104090400, 0x002e080829042120, 0x1040a00210011104, + 0x0020240948141002, 0xe025880d48200108, 0x0041010840020620, 0x0002121040400450, + 0x0148248900004010, 0x2008180460811001, 0x0010308080808600, 0x0804101208011014, +} + +func initMagicAttackTables() { + for sq := range numOfSquaresInBoard { + square := Square(sq) + rookMagicMasks[sq] = rookMagicMask(square) + rookMagicShifts[sq] = uint(numOfSquaresInBoard - bits.OnesCount64(uint64(rookMagicMasks[sq]))) + initMagicAttack(rookMagicAttacks[sq][:], rookMagicMasks[sq], rookMagics[sq], rookMagicShifts[sq], square, slowHVAttack) + + bishopMagicMasks[sq] = bishopMagicMask(square) + bishopMagicShifts[sq] = uint(numOfSquaresInBoard - bits.OnesCount64(uint64(bishopMagicMasks[sq]))) + initMagicAttack( + bishopMagicAttacks[sq][:], + bishopMagicMasks[sq], + bishopMagics[sq], + bishopMagicShifts[sq], + square, + slowDiaAttack, + ) + } +} + +func initMagicAttack( + attacks []bitboard, + mask bitboard, + magic bitboard, + shift uint, + sq Square, + attack func(bitboard, Square) bitboard, +) { + for _, occupied := range magicOccupancies(mask) { + idx := ((occupied & mask) * magic) >> shift + attacks[idx] = attack(occupied, sq) + } +} + +func magicOccupancies(mask bitboard) []bitboard { + bitCount := bits.OnesCount64(uint64(mask)) + occupancies := make([]bitboard, 1<= 1; r-- { + mask |= bbForSquare(NewSquare(File(file), Rank(r))) + } + for f := file + 1; f <= 6; f++ { + mask |= bbForSquare(NewSquare(File(f), Rank(rank))) + } + for f := file - 1; f >= 1; f-- { + mask |= bbForSquare(NewSquare(File(f), Rank(rank))) + } + return mask +} + +func bishopMagicMask(sq Square) bitboard { + file := int(sq.File()) + rank := int(sq.Rank()) + var mask bitboard + for f, r := file+1, rank+1; f <= 6 && r <= 6; f, r = f+1, r+1 { + mask |= bbForSquare(NewSquare(File(f), Rank(r))) + } + for f, r := file-1, rank-1; f >= 1 && r >= 1; f, r = f-1, r-1 { + mask |= bbForSquare(NewSquare(File(f), Rank(r))) + } + for f, r := file-1, rank+1; f >= 1 && r <= 6; f, r = f-1, r+1 { + mask |= bbForSquare(NewSquare(File(f), Rank(r))) + } + for f, r := file+1, rank-1; f <= 6 && r >= 1; f, r = f+1, r-1 { + mask |= bbForSquare(NewSquare(File(f), Rank(r))) + } + return mask +} diff --git a/magic_attack_test.go b/magic_attack_test.go new file mode 100644 index 00000000..487ffeef --- /dev/null +++ b/magic_attack_test.go @@ -0,0 +1,29 @@ +package chess + +import "testing" + +func TestMagicHVAttackMatchesSlowAttack(t *testing.T) { + for sq := range numOfSquaresInBoard { + square := Square(sq) + for _, occupied := range magicOccupancies(rookMagicMasks[sq]) { + got := hvAttack(occupied, square) + want := slowHVAttack(occupied, square) + if got != want { + t.Fatalf("hvAttack(%s, %064b): got %064b, want %064b", square, occupied, got, want) + } + } + } +} + +func TestMagicDiaAttackMatchesSlowAttack(t *testing.T) { + for sq := range numOfSquaresInBoard { + square := Square(sq) + for _, occupied := range magicOccupancies(bishopMagicMasks[sq]) { + got := diaAttack(occupied, square) + want := slowDiaAttack(occupied, square) + if got != want { + t.Fatalf("diaAttack(%s, %064b): got %064b, want %064b", square, occupied, got, want) + } + } + } +} diff --git a/move.go b/move.go index 72873641..436db24b 100644 --- a/move.go +++ b/move.go @@ -39,63 +39,104 @@ const ( EnPassant // Check indicates that the move puts the opposing player in check. Check - // inCheck indicates that the move puts the moving player in check and - // is therefore invalid. - inCheck + // Null indicates that the move flips the side to move without moving + // any piece. Null moves are encoded as "Z0" in PGN and "0000" in UCI. + // They are never generated by ValidMoves and must be inserted + // explicitly via Game.NullMove or Game.UnsafeMove. + Null ) +// NewNullMove returns a Move that flips the side to move without moving any +// piece. The returned move carries the Null MoveTag and has no origin, +// destination, or promotion. Null moves must be inserted via Game.NullMove +// or Game.UnsafeMove; they are rejected by Game.Move because they are never +// part of a position's legal moves. +func NewNullMove() Move { + return Move{tags: Null} +} + +// NewMove returns a Move from origin square s1 to destination square s2. +// The optional promo argument supplies a promotion piece type; when omitted +// the move has no promotion. Tags default to none. +// +// The constructor does not attempt to infer Capture or Check tags because +// those depend on the position context (the piece on s1, the occupant of s2, +// and whether the move leaves the opponent in check). Use Position.IsLegal +// or Game.Move to obtain a fully tagged canonical Move when the position is +// known. +func NewMove(s1, s2 Square, promo ...PieceType) Move { + var p PieceType + if len(promo) > 0 { + p = promo[0] + } + return Move{s1: s1, s2: s2, promo: p} +} + // A Move is the movement of a piece from one square to another. type Move struct { - parent *Move - position *Position // Position after the move - nag string - comments string - command map[string]string // Store commands as key-value pairs - commentBlocks []CommentBlock - structuredComments bool - children []*Move // Main line and variations - number uint - tags MoveTag - s1 Square - s2 Square - promo PieceType -} - -// String returns a string useful for debugging. String doesn't return + tags MoveTag + s1 Square + s2 Square + promo PieceType +} + +// String returns a string useful for debugging. String doesn't return // algebraic notation. -func (m *Move) String() string { +func (m Move) String() string { return m.s1.String() + m.s2.String() + m.promo.String() } // S1 returns the origin square of the move. -func (m *Move) S1() Square { +func (m Move) S1() Square { return m.s1 } // S2 returns the destination square of the move. -func (m *Move) S2() Square { +func (m Move) S2() Square { return m.s2 } // Promo returns promotion piece type of the move. -func (m *Move) Promo() PieceType { +func (m Move) Promo() PieceType { return m.promo } // HasTag returns true if the move contains the MoveTag given. -func (m *Move) HasTag(tag MoveTag) bool { +func (m Move) HasTag(tag MoveTag) bool { return (tag & m.tags) > 0 } -// AddTag adds the given MoveTag to the move's tags using a bitwise OR operation. -// Multiple tags can be combined by calling AddTag multiple times. -func (m *Move) AddTag(tag MoveTag) { +// WithTag returns a copy of the move with the given MoveTag added. +func (m Move) WithTag(tag MoveTag) Move { m.tags |= tag + return m +} + +// MoveNode is one occurrence of a move in a game's move tree. +type MoveNode struct { + move Move + parent *MoveNode + tree *MoveTree + children []*MoveNode + number uint + nags []string + commentBlocks []CommentBlock } -func (m *Move) GetCommand(key string) (string, bool) { - for i := len(m.commentBlocks) - 1; i >= 0; i-- { - block := m.commentBlocks[i] +// Move returns the move value for this move node. +func (n *MoveNode) Move() Move { + if n == nil { + return Move{} + } + return n.move +} + +func (n *MoveNode) GetCommand(key string) (string, bool) { + if n == nil { + return "", false + } + for i := len(n.commentBlocks) - 1; i >= 0; i-- { + block := n.commentBlocks[i] for j := len(block.Items) - 1; j >= 0; j-- { item := block.Items[j] if item.Kind == CommentCommand && item.Key == key { @@ -103,243 +144,216 @@ func (m *Move) GetCommand(key string) (string, bool) { } } } - - if m.command == nil { - m.command = make(map[string]string) - return "", false - } - value, ok := m.command[key] - return value, ok + return "", false } -func (m *Move) SetCommand(key, value string) { - if m.command == nil { - m.command = make(map[string]string) - } - m.command[key] = value - - if !m.structuredComments { - m.rebuildLegacyCommentBlock() +func (n *MoveNode) SetCommand(key, value string) { + if n == nil { return } - - m.ensureCommentBlocksFromLegacy() - for blockIdx := len(m.commentBlocks) - 1; blockIdx >= 0; blockIdx-- { - for itemIdx := len(m.commentBlocks[blockIdx].Items) - 1; itemIdx >= 0; itemIdx-- { - item := &m.commentBlocks[blockIdx].Items[itemIdx] + for blockIdx := len(n.commentBlocks) - 1; blockIdx >= 0; blockIdx-- { + for itemIdx := len(n.commentBlocks[blockIdx].Items) - 1; itemIdx >= 0; itemIdx-- { + item := &n.commentBlocks[blockIdx].Items[itemIdx] if item.Kind == CommentCommand && item.Key == key { item.Value = value return } } } - - if len(m.commentBlocks) == 0 { - m.commentBlocks = append(m.commentBlocks, CommentBlock{}) + if len(n.commentBlocks) == 0 { + n.commentBlocks = append(n.commentBlocks, CommentBlock{}) } - last := len(m.commentBlocks) - 1 - m.commentBlocks[last].Items = append(m.commentBlocks[last].Items, CommentItem{ + last := len(n.commentBlocks) - 1 + n.commentBlocks[last].Items = append(n.commentBlocks[last].Items, CommentItem{ Kind: CommentCommand, Key: key, Value: value, }) } -func (m *Move) SetComment(comment string) { - commands := m.command - m.comments = comment - m.commentBlocks = nil - m.structuredComments = false - if comment != "" || len(commands) > 0 { - m.rebuildLegacyCommentBlockWithCommands(commands) +func (n *MoveNode) SetComment(comment string) { + if n == nil { + return + } + if comment == "" { + n.commentBlocks = nil + return } + n.commentBlocks = []CommentBlock{{Items: []CommentItem{{Kind: CommentText, Text: comment}}}} } -func (m *Move) AddComment(comment string) { - if !m.structuredComments { - m.comments += comment - m.rebuildLegacyCommentBlock() +func (n *MoveNode) AddComment(comment string) { + if n == nil || comment == "" { return } - - m.ensureCommentBlocksFromLegacy() - if len(m.commentBlocks) == 0 { - m.commentBlocks = []CommentBlock{{Items: []CommentItem{{Kind: CommentText, Text: comment}}}} - m.syncLegacyAnnotationsFromBlocks() + if len(n.commentBlocks) == 0 { + n.commentBlocks = []CommentBlock{{Items: []CommentItem{{Kind: CommentText, Text: comment}}}} return } - - lastBlock := len(m.commentBlocks) - 1 - for i := len(m.commentBlocks[lastBlock].Items) - 1; i >= 0; i-- { - item := &m.commentBlocks[lastBlock].Items[i] + lastBlock := len(n.commentBlocks) - 1 + for i := len(n.commentBlocks[lastBlock].Items) - 1; i >= 0; i-- { + item := &n.commentBlocks[lastBlock].Items[i] if item.Kind == CommentText { item.Text += comment - m.syncLegacyAnnotationsFromBlocks() return } } - m.commentBlocks[lastBlock].Items = append(m.commentBlocks[lastBlock].Items, CommentItem{Kind: CommentText, Text: comment}) - m.syncLegacyAnnotationsFromBlocks() + n.commentBlocks[lastBlock].Items = append(n.commentBlocks[lastBlock].Items, CommentItem{Kind: CommentText, Text: comment}) } -func (m *Move) Comments() string { - if len(m.commentBlocks) > 0 { - return flattenCommentText(m.commentBlocks) +func (n *MoveNode) Comments() string { + if n == nil { + return "" } - return m.comments + return flattenCommentText(n.commentBlocks) } -// CommentBlocks returns a defensive copy of the move's structured PGN comment blocks. -func (m *Move) CommentBlocks() []CommentBlock { - m.ensureCommentBlocksFromLegacy() - blocks := make([]CommentBlock, len(m.commentBlocks)) - for i, block := range m.commentBlocks { - blocks[i].Items = append([]CommentItem(nil), block.Items...) +// CommentBlocks returns a defensive copy of the move node's structured PGN comment blocks. +func (n *MoveNode) CommentBlocks() []CommentBlock { + if n == nil { + return nil } - return blocks + return copyCommentBlocks(n.commentBlocks) } -func (m *Move) NAG() string { - return m.nag -} - -func (m *Move) SetNAG(nag string) { - m.nag = nag +// NAGs returns a defensive copy of the move node's numeric annotation glyphs in +// their canonical "$N" form, in the order they were added. +func (n *MoveNode) NAGs() []string { + if n == nil { + return nil + } + return append([]string(nil), n.nags...) } -func (m *Move) Parent() *Move { - return m.parent +// SetNAGs replaces all of the move node's NAGs. Each value is normalised via +// ParseNAG. The replacement is all-or-nothing: if any value is malformed the +// node is left unchanged and the error is returned. +func (n *MoveNode) SetNAGs(nags []string) error { + if n == nil { + return nil + } + normalised := make([]string, 0, len(nags)) + for _, nag := range nags { + parsed, err := ParseNAG(nag) + if err != nil { + return err + } + normalised = append(normalised, parsed) + } + n.nags = normalised + return nil } -func (m *Move) Position() *Position { - return m.position +// AddNAG normalises and appends a single NAG to the move node. Order is +// preserved. A malformed value leaves the node unchanged. +func (n *MoveNode) AddNAG(nag string) error { + if n == nil { + return nil + } + parsed, err := ParseNAG(nag) + if err != nil { + return err + } + n.nags = append(n.nags, parsed) + return nil } -func (m *Move) Children() []*Move { - return m.children +func (n *MoveNode) Parent() *MoveNode { + if n == nil { + return nil + } + return n.parent } -func (m *Move) Number() int { - ret := int(m.number) - if ret == 0 { // 0 indicates the 'dummy' rootMove - ret = 1 +// Position returns the position reached by playing this node's move from +// its parent's position. It saves and restores the tree's active cursor so +// the read is observationally pure under ADR-016's single-active-cursor +// invariant. See ADR-018 for the lazy-position design. +func (n *MoveNode) Position() *Position { + if n == nil || n.tree == nil { + return nil } - - return ret + defer n.tree.setCurrent(n.tree.current) + n.tree.setCurrent(n) + return n.tree.pos.copy() } -// FullMoveNumber returns the full move number (increments after Black's move). -func (m *Move) FullMoveNumber() int { - return m.Number() +func (n *MoveNode) Children() []*MoveNode { + if n == nil { + return nil + } + return append([]*MoveNode{}, n.children...) } -// Ply returns the half-move number (increments every move). -func (m *Move) Ply() int { - if m == nil { - return 0 - } - if m.position == nil { - return 0 +// ChildrenIter returns an allocation-free iterator over the continuations. +func (n *MoveNode) ChildrenIter(yield func(*MoveNode) bool) { + if n == nil { + return } - moveNumber := int(m.number) - // we reverse the color because the position is after the move has been played - if m.position.turn == Black { - // After the move, it's White's turn, so the move was by Black - return (moveNumber-1)*2 + 1 + for _, continuation := range n.children { + if !yield(continuation) { + return + } } - // After the move, it's Black's turn, so the move was by White - return (moveNumber)*2 + 0 } -// Clone returns a deep copy of a move. -// -// Per-field exceptions: -// -// parent: not copied; the clone'd move has no parent -// children: not copied; the clone'd move has no children -func (m *Move) Clone() *Move { - ret := &Move{} - ret.parent = nil - ret.position = m.position.copy() - ret.nag = m.nag - ret.comments = m.comments - ret.commentBlocks = copyCommentBlocks(m.commentBlocks) - ret.structuredComments = m.structuredComments - ret.children = make([]*Move, 0) - ret.number = m.number - ret.tags = m.tags - ret.s1 = m.s1 - ret.s2 = m.s2 - ret.promo = m.promo - - ret.command = make(map[string]string) - for k, v := range m.command { - ret.command[k] = v +func (n *MoveNode) Number() int { + if n == nil { + return 0 } - - return ret -} - -func (m *Move) addCommentBlock(block CommentBlock) { - if len(block.Items) == 0 { - return + ret := int(n.number) + if ret == 0 { + ret = 1 } - m.commentBlocks = append(m.commentBlocks, block) - m.structuredComments = true - m.syncLegacyAnnotationsFromBlocks() + return ret } -func (m *Move) hasAnnotations() bool { - return len(m.commentBlocks) > 0 || m.comments != "" || len(m.command) > 0 +// FullMoveNumber returns the full move number (increments after Black's move). +func (n *MoveNode) FullMoveNumber() int { + return n.Number() } -func (m *Move) syncLegacyAnnotationsFromBlocks() { - m.comments = flattenCommentText(m.commentBlocks) - m.command = make(map[string]string) - for _, block := range m.commentBlocks { - for _, item := range block.Items { - if item.Kind == CommentCommand { - m.command[item.Key] = item.Value - } - } +// Ply returns the half-move number (increments every move). For the synthetic +// root it returns 0; otherwise it equals the depth of the parent chain from +// n up to (not including) the synthetic root. +func (n *MoveNode) Ply() int { + if n == nil || n.parent == nil { + return 0 } - if len(m.command) == 0 { - m.command = nil + depth := 0 + for cur := n; cur != nil && cur.parent != nil; cur = cur.parent { + depth++ } + return depth } -func (m *Move) ensureCommentBlocksFromLegacy() { - if len(m.commentBlocks) > 0 || (m.comments == "" && len(m.command) == 0) { +func (n *MoveNode) addCommentBlock(block CommentBlock) { + if n == nil || len(block.Items) == 0 { return } - - block := CommentBlock{} - if m.comments != "" { - block.Items = append(block.Items, CommentItem{Kind: CommentText, Text: m.comments}) - } - for _, key := range sortedCommandKeys(m.command) { - block.Items = append(block.Items, CommentItem{Kind: CommentCommand, Key: key, Value: m.command[key]}) - } - m.commentBlocks = []CommentBlock{block} + n.commentBlocks = append(n.commentBlocks, block) } -func (m *Move) rebuildLegacyCommentBlock() { - m.rebuildLegacyCommentBlockWithCommands(m.command) +func (n *MoveNode) hasAnnotations() bool { + return n != nil && (len(n.commentBlocks) > 0 || len(n.nags) > 0) } -func (m *Move) rebuildLegacyCommentBlockWithCommands(commands map[string]string) { - block := CommentBlock{} - if m.comments != "" { - block.Items = append(block.Items, CommentItem{Kind: CommentText, Text: m.comments}) +func (n *MoveNode) clone() *MoveNode { + if n == nil { + return nil } - for _, key := range sortedCommandKeys(commands) { - block.Items = append(block.Items, CommentItem{Kind: CommentCommand, Key: key, Value: commands[key]}) + ret := &MoveNode{ + move: n.move, + number: n.number, + nags: append([]string(nil), n.nags...), + commentBlocks: copyCommentBlocks(n.commentBlocks), } - if len(block.Items) == 0 { - m.commentBlocks = nil - return + for _, child := range n.children { + childClone := child.clone() + childClone.parent = ret + ret.children = append(ret.children, childClone) } - m.commentBlocks = []CommentBlock{block} + return ret } func flattenCommentText(blocks []CommentBlock) string { @@ -365,16 +379,3 @@ func copyCommentBlocks(src []CommentBlock) []CommentBlock { } return blocks } - -func (m *Move) cloneChildren(srcChildren []*Move) { - if len(srcChildren) == 0 { - return - } - - for _, srcMv := range srcChildren { - dstMv := srcMv.Clone() - dstMv.parent = m - dstMv.cloneChildren(srcMv.children) - m.children = append(m.children, dstMv) - } -} diff --git a/move_applier.go b/move_applier.go new file mode 100644 index 00000000..d2b92cc5 --- /dev/null +++ b/move_applier.go @@ -0,0 +1,385 @@ +package chess + +// This file is the single source of truth for "what changes about a Position +// when a non-null Move is played": the incremental bookkeeping rule +// (moveCount, halfMoveClock, castleRights, enPassant, board, turn, inCheck, +// hash) and the shared physical-fact descriptor (moveEffect) for the board +// mutation and the Zobrist hash delta. The copy-on-write applier +// (Position.Update) and the in-place applier (Position.makeMove) both delegate +// here to applyMove, so the rule cannot drift between them. applyMove also +// computes the post-move Zobrist hash from the pre-move state via updateHash, +// so the board mutation and the hash delta read one interpretation of +// en-passant squares, castle rook squares, and capture targets. +// +// Null moves are a separate concern (nullUpdate) and intentionally do not share +// the applyMove body: a null move never touches the board, castling rights, or +// pieces, so folding it in would force applyMove to skip a board copy it can +// otherwise avoid. They share only the moveCount rule via nextMoveCount. +// +// updateHash is called while pos still holds pre-move state, so its reads of +// pos.board / pos.hash / pos.castleRights / pos.enPassantSquare are the +// pre-move values; ncr, ep, and eff carry the post-move bookkeeping and the +// physical descriptor. See docs/adr/0001-single-move-application-core.md and +// docs/adr/0017-zobrist-hash-consolidation.md. + +// nullUpdate returns a new position that is identical to the receiver except +// for the side to move, the half-move clock, the full-move clock, and the +// en-passant square. The half-move clock is incremented as for a quiet move, +// the full-move clock advances when Black passed, and the en-passant capture +// right is cleared. The board, castling rights, and pieces are unchanged. +// The Zobrist hash is recomputed incrementally. +func (pos *Position) nullUpdate() *Position { + newPos := &Position{ + board: pos.board, + turn: pos.turn.Other(), + castleRights: pos.castleRights, + enPassantSquare: NoSquare, + halfMoveClock: pos.halfMoveClock + 1, + moveCount: pos.nextMoveCount(), + variant: pos.variant, + } + + // Recompute inCheck and checkers for the new side to move. The board is + // unchanged, so the new side may now be in check if a piece attacks their king. + newPos.inCheck, newPos.checkers = checkState(newPos) + newPos.hash = pos.nullUpdateHash(newPos.enPassantSquare) + return newPos +} + +// nextMoveCount returns the full-move number after the side to move has moved. +// The number advances when Black is to move. This is the single source for the +// moveCount rule; it was previously inlined in Update, makeMove, and nullUpdate. +func (pos *Position) nextMoveCount() int { + if pos.turn == Black { + return pos.moveCount + 1 + } + return pos.moveCount +} + +// moveEffect is the single interpretation of a move's physical facts. The board +// mutation (Board.update) and the Zobrist delta (updateHash) both read it +// instead of re-deriving en-passant squares, castle rook squares, and capture +// targets from MoveTags, so the two cannot drift. +// +// A zero value (moving == NoPiece) is returned for degenerate moves with no +// piece on the origin square; Board.update treats this as a no-op, as it did +// before the descriptor existed. +type moveEffect struct { + moving Piece // piece on s1 before the move + landing Piece // piece that ends on s2 (promo piece, else moving) + capPiece Piece // captured piece, NoPiece if none + capSq Square // capture square (s2, or s2±8 for en passant) + rookFrom Square // castle rook origin, NoSquare if not a castle + rookTo Square // castle rook destination, NoSquare if not a castle +} + +// computeMoveEffect derives the physical facts of m from the pre-move board. +// It is the only place that knows how the special-move tags (EnPassant, +// KingSideCastle, QueenSideCastle) map to physical effects; both Board.update +// and updateHash consume the returned struct. +// +// Every effect (captured square, castle rook squares) is derived from the +// moving piece's color so unsafe moves with a mismatched turn cannot apply +// effects for the wrong side. Returns the zero effect (every optional field +// at NoSquare / NoPiece) when m.s1 is empty. +func computeMoveEffect(b *Board, m Move) moveEffect { + moving := b.Piece(m.s1) + if moving == NoPiece { + return moveEffect{capSq: NoSquare, rookFrom: NoSquare, rookTo: NoSquare} + } + + eff := moveEffect{ + moving: moving, + landing: moving, + capSq: NoSquare, + rookFrom: NoSquare, + rookTo: NoSquare, + } + if m.promo != NoPieceType { + eff.landing = NewPiece(m.promo, moving.Color()) + } + + switch { + case m.HasTag(EnPassant) && !b.isOccupied(m.s2): + // Real e.p.: m.s2 is empty, so capture the pawn on the adjacent + // rank. If m.s2 is occupied the EnPassant tag is being misused on + // a normal capture; fall through to handle it as such and remove + // the piece actually on m.s2 rather than ghosting it in the + // bitboards. + if moving.Color() == White { + eff.capSq = m.s2 - 8 + } else { + eff.capSq = m.s2 + 8 + } + eff.capPiece = b.Piece(eff.capSq) + case b.isOccupied(m.s2): + eff.capPiece = b.Piece(m.s2) + eff.capSq = m.s2 + } + + eff.rookFrom, eff.rookTo = castleRookMove(b, m, moving.Color()) + return eff +} + +// castleRookMove returns the origin and destination squares of the rook in a +// castling move, or (NoSquare, NoSquare) when m carries no castle tag. The +// destination is always the standard square (f for king side, d for queen +// side); the origin is derived from the board: the nearest friendly rook to the +// king's right (king side) or left (queen side) on the back rank. m.s1 is the +// king's origin in a castling move. This serves both standard chess (rook on +// a1/h1/a8/h8) and Chess960 (rook anywhere on the back rank). +func castleRookMove(b *Board, m Move, c Color) (Square, Square) { + kingSide := m.HasTag(KingSideCastle) + queenSide := m.HasTag(QueenSideCastle) + if !kingSide && !queenSide { + return NoSquare, NoSquare + } + var ( + rank Rank + rook Piece + rookTo Square + ) + if c == White { + rank, rook = Rank1, WhiteRook + if kingSide { + rookTo = F1 + } else { + rookTo = D1 + } + } else { + rank, rook = Rank8, BlackRook + if kingSide { + rookTo = F8 + } else { + rookTo = D8 + } + } + kingFile := int(m.s1.File()) + if kingSide { + for f := kingFile + 1; f < 8; f++ { + if b.Piece(NewSquare(File(f), rank)) == rook { + return NewSquare(File(f), rank), rookTo + } + } + } else { + for f := kingFile - 1; f >= 0; f-- { + if b.Piece(NewSquare(File(f), rank)) == rook { + return NewSquare(File(f), rank), rookTo + } + } + } + return NoSquare, rookTo +} + +// applyMove applies the non-null bookkeeping rule to pos in place. It updates +// the board, side to move, castling rights, en-passant square, half-move clock, +// full-move number, the in-check flag, the Zobrist hash, and invalidates the +// cached legal-move and status values. +// +// updateHash is called while pos still holds pre-move state, so its reads of +// pos.board / pos.hash / pos.castleRights / pos.enPassantSquare are the +// pre-move values; ncr, ep, and eff carry the post-move bookkeeping and the +// physical descriptor. The new hash is assigned alongside the other post-move +// fields after the board mutation. +// +// Pre-move-derived values (castle rights, en passant, half-move clock) are +// computed before board.update mutates the board, since updateCastleRights and +// updateEnPassantSquare both inspect the origin square on the pre-move board. +// isInCheck is computed after, once the new side to move and board are in +// place. The computed effect is returned so undo-style callers (the MoveTree +// cursor's makeMoveCursor) can record the inverse without recomputing it; +// statement-style callers (perft's makeMove) simply ignore it. +// applyMove serves both COW callers (Position.Update) and in-place +// callers (the cursor's makeMoveCursor). See ADR-016 for the +// single-active-cursor reasoning. +func (pos *Position) applyMove(m Move) moveEffect { + eff := computeMoveEffect(&pos.board, m) + moveCount := pos.nextMoveCount() + ncr := pos.updateCastleRights(m) + p := eff.moving + halfMove := 0 + if p.Type() != Pawn && eff.capPiece == NoPiece { + halfMove = pos.halfMoveClock + 1 + } + ep := pos.updateEnPassantSquare(m) + + // Compute the hash delta while pos still holds pre-move state. updateHash + // reads pos.board / pos.hash / pos.castleRights / pos.enPassantSquare as + // the pre-move values; ncr, ep, and eff describe the post-move state. + newHash := pos.updateHash(m, ncr, ep, eff) + + pos.board.update(m, eff) + pos.turn = pos.turn.Other() + pos.castleRights = ncr + pos.enPassantSquare = ep + pos.halfMoveClock = halfMove + pos.moveCount = moveCount + pos.hash = newHash + pos.validMoves = nil + pos.statusCached = false + pos.inCheck, pos.checkers = checkState(pos) + return eff +} + +// cursorUndo is the MoveTree cursor's slim undo record: the inverse of the +// move plus scalar state, ~56 bytes versus ~264 for perft's full-state +// positionUndo. The tree retains one entry per played level for the game's +// lifetime, so size matters here; perft's undo is stack-allocated on a hot +// path and stays untouched (ADR-0001). validMoves/status caches are not +// captured: applyMove invalidates both on the forward path, so restoring +// them as invalid matches the forward state exactly. +type cursorUndo struct { + hash uint64 + moveCount int + halfMoveClock int + castleRights CastleRights + eff moveEffect + enPassantSquare Square + turn Color + inCheck bool + checkers bitboard +} + +// makeMoveCursor applies m in place and returns a slim undo record. +func (pos *Position) makeMoveCursor(m Move) cursorUndo { + u := cursorUndo{ + hash: pos.hash, + moveCount: pos.moveCount, + halfMoveClock: pos.halfMoveClock, + castleRights: pos.castleRights, + enPassantSquare: pos.enPassantSquare, + turn: pos.turn, + inCheck: pos.inCheck, + checkers: pos.checkers, + } + if m.HasTag(Null) { + next := pos.nullUpdate() + *pos = *next + return u + } + u.eff = pos.applyMove(m) + return u +} + +// unmakeMoveCursor restores the pre-move position captured by makeMoveCursor. +// m must be the move that produced u. eff.moving == NoPiece (null move) +// makes board.unapply a no-op, leaving only the scalar restore. +func (pos *Position) unmakeMoveCursor(m Move, u cursorUndo) { + pos.board.unapply(m, u.eff) + pos.hash = u.hash + pos.moveCount = u.moveCount + pos.halfMoveClock = u.halfMoveClock + pos.castleRights = u.castleRights + pos.enPassantSquare = u.enPassantSquare + pos.turn = u.turn + pos.inCheck = u.inCheck + pos.checkers = u.checkers + pos.validMoves = nil + pos.statusCached = false +} + +// updateCastleRights returns the castling rights after m is played. It inspects +// the origin square on the pre-move board, so it must be called before +// board.update. +func (pos *Position) updateCastleRights(m Move) CastleRights { + if pos.variant == Chess960 { + return pos.updateCastleRightsChess960(m) + } + removeWK := false + removeWQ := false + removeBK := false + removeBQ := false + p := pos.board.Piece(m.s1) + if p == WhiteKing || m.s1 == H1 || m.s2 == H1 { + removeWK = true + } + if p == WhiteKing || m.s1 == A1 || m.s2 == A1 { + removeWQ = true + } + if p == BlackKing || m.s1 == H8 || m.s2 == H8 { + removeBK = true + } + if p == BlackKing || m.s1 == A8 || m.s2 == A8 { + removeBQ = true + } + if !removeWK && !removeWQ && !removeBK && !removeBQ { + return pos.castleRights + } + ncr := pos.castleRights + if removeWK { + ncr.White.KingSide = false + } + if removeWQ { + ncr.White.QueenSide = false + } + if removeBK { + ncr.Black.KingSide = false + } + if removeBQ { + ncr.Black.QueenSide = false + } + return ncr +} + +// updateCastleRightsChess960 returns the castling rights after m is played in a +// Chess960 position. A held right is lost when the king moves, or when the rook +// granting that right moves or is captured. The granting rook is located on the +// back rank relative to the king, so this must be called before board.update. +func (pos *Position) updateCastleRightsChess960(m Move) CastleRights { + ncr := pos.castleRights + if ncr.White.KingSide && pos.chess960RightLost(White, KingSide, m) { + ncr.White.KingSide = false + } + if ncr.White.QueenSide && pos.chess960RightLost(White, QueenSide, m) { + ncr.White.QueenSide = false + } + if ncr.Black.KingSide && pos.chess960RightLost(Black, KingSide, m) { + ncr.Black.KingSide = false + } + if ncr.Black.QueenSide && pos.chess960RightLost(Black, QueenSide, m) { + ncr.Black.QueenSide = false + } + return ncr +} + +// chess960RightLost reports whether the castling right (c, side) is lost by +// playing m: the king moved off its square, or the granting rook moved or was +// captured. Returns false if the king or rook cannot be located. +func (pos *Position) chess960RightLost(c Color, side Side, m Move) bool { + kingFile := backRankKingFile(&pos.board, c) + if kingFile < 0 { + return false + } + rank := Rank1 + if c == Black { + rank = Rank8 + } + kingSq := NewSquare(File(kingFile), rank) + rf := rookFileForSide(&pos.board, c, kingFile, side) + if rf < 0 { + return false + } + rookSq := NewSquare(File(rf), rank) + return m.s1 == kingSq || m.s1 == rookSq || m.s2 == rookSq +} + +// updateEnPassantSquare returns the en-passant target square created by m, or +// NoSquare. It inspects the pre-move board and side to move, so it must be +// called before board.update and the side-to-move flip. +func (pos *Position) updateEnPassantSquare(m Move) Square { + const squaresPerRank = 8 + p := pos.board.Piece(m.s1) + if p.Type() != Pawn { + return NoSquare + } + if pos.turn == White && + (bbForSquare(m.s1)&bbRank2) != 0 && + (bbForSquare(m.s2)&bbRank4) != 0 { + return m.s2 - squaresPerRank + } else if pos.turn == Black && + (bbForSquare(m.s1)&bbRank7) != 0 && + (bbForSquare(m.s2)&bbRank5) != 0 { + return m.s2 + squaresPerRank + } + return NoSquare +} diff --git a/move_applier_test.go b/move_applier_test.go new file mode 100644 index 00000000..4788e8e1 --- /dev/null +++ b/move_applier_test.go @@ -0,0 +1,482 @@ +package chess + +import ( + "testing" +) + +// TestComputeMoveEffect pins down the single interpretation of a move's +// physical facts (en-passant captured square, castle rook squares, capture +// target, landing piece). Board.update and updateHash both read this struct +// instead of each re-reading MoveTags; this test is the focused guard so any +// future drift in the descriptor surfaces here, not at perft. +func TestComputeMoveEffect(t *testing.T) { + cases := []struct { + name string + fen string + m Move + want moveEffect + }{ + { + name: "quiet pawn push", + fen: "4k3/8/8/8/8/8/4P3/4K3 w - - 0 1", + m: Move{s1: E2, s2: E4}, + want: moveEffect{ + moving: WhitePawn, + landing: WhitePawn, + capSq: NoSquare, + rookFrom: NoSquare, + rookTo: NoSquare, + }, + }, + { + name: "normal capture", + fen: "3k4/8/8/4Q3/8/8/8/4K3 w - - 0 1", + m: Move{s1: E5, s2: D8, tags: Capture}, + want: moveEffect{ + moving: WhiteQueen, + landing: WhiteQueen, + capPiece: BlackKing, + capSq: D8, + rookFrom: NoSquare, + rookTo: NoSquare, + }, + }, + { + name: "white en passant captures pawn at s2-8", + fen: "4k3/8/8/3pP3/8/8/8/4K3 w - d6 0 1", + m: Move{s1: E5, s2: D6, tags: EnPassant | Capture}, + want: moveEffect{ + moving: WhitePawn, + landing: WhitePawn, + capPiece: BlackPawn, + capSq: D5, + rookFrom: NoSquare, + rookTo: NoSquare, + }, + }, + { + name: "black en passant captures pawn at s2+8", + fen: "4k3/8/8/8/3pP3/8/8/4K3 b - e3 0 1", + m: Move{s1: D4, s2: E3, tags: EnPassant | Capture}, + want: moveEffect{ + moving: BlackPawn, + landing: BlackPawn, + capPiece: WhitePawn, + capSq: E4, + rookFrom: NoSquare, + rookTo: NoSquare, + }, + }, + { + name: "white king-side castle", + fen: "4k3/8/8/8/8/8/8/R3K2R w KQ - 0 1", + m: Move{s1: E1, s2: G1, tags: KingSideCastle}, + want: moveEffect{ + moving: WhiteKing, + landing: WhiteKing, + capSq: NoSquare, + rookFrom: H1, + rookTo: F1, + }, + }, + { + name: "white queen-side castle", + fen: "4k3/8/8/8/8/8/8/R3K2R w KQ - 0 1", + m: Move{s1: E1, s2: C1, tags: QueenSideCastle}, + want: moveEffect{ + moving: WhiteKing, + landing: WhiteKing, + capSq: NoSquare, + rookFrom: A1, + rookTo: D1, + }, + }, + { + name: "black king-side castle", + fen: "r3k2r/8/8/8/8/8/8/4K3 b kq - 0 1", + m: Move{s1: E8, s2: G8, tags: KingSideCastle}, + want: moveEffect{ + moving: BlackKing, + landing: BlackKing, + capSq: NoSquare, + rookFrom: H8, + rookTo: F8, + }, + }, + { + name: "black queen-side castle", + fen: "r3k2r/8/8/8/8/8/8/4K3 b kq - 0 1", + m: Move{s1: E8, s2: C8, tags: QueenSideCastle}, + want: moveEffect{ + moving: BlackKing, + landing: BlackKing, + capSq: NoSquare, + rookFrom: A8, + rookTo: D8, + }, + }, + { + name: "promotion to queen (no capture)", + fen: "4k3/P7/8/8/8/8/8/4K3 w - - 0 1", + m: Move{s1: A7, s2: A8, promo: Queen}, + want: moveEffect{ + moving: WhitePawn, + landing: WhiteQueen, + capSq: NoSquare, + rookFrom: NoSquare, + rookTo: NoSquare, + }, + }, + { + name: "promotion-capture", + fen: "3rk3/4P3/8/8/8/8/8/4K3 w - - 0 1", + m: Move{s1: E7, s2: D8, promo: Queen, tags: Capture}, + want: moveEffect{ + moving: WhitePawn, + landing: WhiteQueen, + capPiece: BlackRook, + capSq: D8, + rookFrom: NoSquare, + rookTo: NoSquare, + }, + }, + { + name: "degenerate move with empty origin returns zero effect", + fen: "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + m: Move{s1: E4, s2: E4}, + want: moveEffect{capSq: NoSquare, rookFrom: NoSquare, rookTo: NoSquare}, + }, + { + name: "en passant tag with occupied destination falls through to normal capture", + fen: "4k3/8/8/3q4/4P3/8/8/4K3 w - d6 0 1", + m: Move{s1: E4, s2: D5, tags: EnPassant | Capture}, + want: moveEffect{ + moving: WhitePawn, + landing: WhitePawn, + capPiece: BlackQueen, + capSq: D5, + rookFrom: NoSquare, + rookTo: NoSquare, + }, + }, + } + + for _, tc := range cases { + t.Run(tc.name, func(t *testing.T) { + pos, err := decodeFENUnsafe(tc.fen) + if err != nil { + t.Fatalf("FEN decode: %v", err) + } + got := computeMoveEffect(&pos.board, tc.m) + if got.moving != tc.want.moving || + got.landing != tc.want.landing || + got.capPiece != tc.want.capPiece || + got.capSq != tc.want.capSq || + got.rookFrom != tc.want.rookFrom || + got.rookTo != tc.want.rookTo { + t.Errorf("computeMoveEffect(%s, %s):\n got %+v\n want %+v", + tc.fen, tc.m, got, tc.want) + } + }) + } +} + +// TestUnsafeTransitionConsistency guards the two invariants that unsafe moves +// through Position.Update (and thus Game.UnsafeMove / Game.UnsafeMoveText) +// must still uphold: +// +// - Special-move effects (en-passant captured square, castle rook squares) +// are driven by the moving piece's color, not by Position.turn. Otherwise +// an unsafe castling or en-passant move played against the wrong turn +// produces rook moves / captures on the wrong rank and silently corrupts +// bitboards and mailbox. +// - Capturing onto a square occupied by a friendly piece (which Game.Move +// rejects) is applied without leaving whiteSqs/blackSqs inconsistent with +// the piece bitboards. The capture removal happens before the mover's +// aggregate occupancy shifts to s2, so the same square can be cleared and +// re-added under the mover's color without an aggregate-occupancy gap. +func TestUnsafeTransitionConsistency(t *testing.T) { + t.Run("black king-side castle with white nominally to move moves H8 rook, not H1", func(t *testing.T) { + opt, err := FEN("r3k2r/8/8/8/8/8/8/4K3 w kq - 0 1") + if err != nil { + t.Fatal(err) + } + g := NewGame(opt) + if _, err := g.UnsafeMove(Move{s1: E8, s2: G8, tags: KingSideCastle}, nil); err != nil { + t.Fatalf("UnsafeMove() error = %v", err) + } + b := g.Position().Board() + if err := verifyMailboxConsistency(b); err != nil { + t.Fatalf("board inconsistent: %v", err) + } + if got := b.Piece(F8); got != BlackRook { + t.Errorf("piece on F8 = %v, want BlackRook", got) + } + if got := b.Piece(H8); got != NoPiece { + t.Errorf("piece on H8 = %v, want empty (rook moved off)", got) + } + }) + + t.Run("black en passant tagged while white to move still removes pawn at s2+8", func(t *testing.T) { + opt, err := FEN("4k3/8/8/3pP3/8/8/8/4K3 w - d6 0 1") + if err != nil { + t.Fatal(err) + } + g := NewGame(opt) + // Move the white pawn to D6 with an EnPassant tag. The descriptor must + // derive capSq from the moving piece's color (white), so the captured + // pawn sits on D5 regardless of the position's nominal turn. + if _, err := g.UnsafeMove(Move{s1: E5, s2: D6, tags: EnPassant | Capture}, nil); err != nil { + t.Fatalf("UnsafeMove() error = %v", err) + } + b := g.Position().Board() + if err := verifyMailboxConsistency(b); err != nil { + t.Fatalf("board inconsistent: %v", err) + } + if got := b.Piece(D5); got != NoPiece { + t.Errorf("piece on D5 = %v, want empty (e.p. captured)", got) + } + }) + + t.Run("king moving onto friendly square preserves mailbox invariants", func(t *testing.T) { + g := NewGame() + // Startpos: white king on E1, white pawn on E2. UnsafeMove E1->E2 is + // illegal but unsafe APIs accept it. The king should end up on E2, + // with the original pawn gone and the white aggregate occupancy + // consistent with the mailbox and per-piece bitboards. + if _, err := g.UnsafeMove(Move{s1: E1, s2: E2}, nil); err != nil { + t.Fatalf("UnsafeMove() error = %v", err) + } + b := g.Position().Board() + if err := verifyMailboxConsistency(b); err != nil { + t.Fatalf("board inconsistent: %v", err) + } + if got := b.Piece(E2); got != WhiteKing { + t.Errorf("piece on E2 = %v, want WhiteKing", got) + } + if got := b.Piece(E1); got != NoPiece { + t.Errorf("piece on E1 = %v, want empty (king left)", got) + } + }) + + t.Run("en passant tag with occupied destination captures the piece on s2, not s2±8", func(t *testing.T) { + pos, err := decodeFENUnsafe("4k3/8/8/3q4/4P3/8/8/4K3 w - d6 0 1") + if err != nil { + t.Fatal(err) + } + pos.inCheck, pos.checkers = checkState(pos) + g := NewGame() + g.tree.setRootPosition(pos) + g.evaluatePositionStatus() + // White pawn on E4 pushing to D5 (where the black queen sits) but + // tagged as en-passant. Real e.p. would clear D5's adjacent square + // instead; a misuse of the tag must demote to a normal capture + // rather than ghost the queen in the per-piece bitboards. + if _, err := g.UnsafeMove(Move{s1: E4, s2: D5, tags: EnPassant | Capture}, nil); err != nil { + t.Fatalf("UnsafeMove() error = %v", err) + } + b := g.Position().Board() + if err := verifyMailboxConsistency(b); err != nil { + t.Fatalf("board inconsistent: %v", err) + } + if got := b.Piece(D5); got != WhitePawn { + t.Errorf("piece on D5 = %v, want WhitePawn", got) + } + // The queen's bitboard must reflect the capture; the incremental + // hash should match a full recompute. + pre := g.Position() + if got, want := pre.ZobristHash(), pre.computeHash(); got != want { + t.Errorf("hash drift: incremental=%x recompute=%x", got, want) + } + }) +} + +// TestApplyMoveDifferential runs the copy-on-write applier (Position.Update) and +// the in-place applier (Position.makeMove) in lockstep over the canonical perft +// positions and asserts: +// - the two paths reach byte-identical FENs after every move, and +// - on both paths, the incremental Zobrist hash equals a full recompute at +// every node walked. +// +// The hash guard is the depth-multiplied form of TestZobristHashIncrementalCorrectness: +// now that Board.update and updateHash share the moveEffect descriptor, this +// is a structural check (drift is impossible) rather than a regression check, +// but we still surface it at depth so a future change to either consumer would +// fail loudly here rather than silently corrupt transposition tables. +// +// What the FEN comparison guards: perft node counts are blind to the half-move +// clock and full-move number, so a drift in those fields would not change node +// counts yet would corrupt the 50/75-move draw rules. Position.String emits +// the full FEN, which includes both counters, so this comparison is the guard +// against that drift class. +// +// The hash comparison now runs on both paths: applyMove computes the +// post-move hash itself so the in-place path (used by the lazy position +// cursor in ADR-016) carries a correct hash for repetition detection +// (numOfRepetitions) the same way Update does. +func TestApplyMoveDifferential(t *testing.T) { + const depth = 3 + fens := []struct{ name, fen string }{ + {"startpos", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"}, + {"kiwipete", "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1"}, + {"pos3", "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1"}, + {"pos4", "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1"}, + {"pos5", "r2q1rk1/pP1p2pp/Q4n2/bbp1p3/Np6/1B3NBn/pPPP1PPP/R3K2R b KQ - 0 1"}, + {"pos6", "rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8"}, + } + + for _, c := range fens { + t.Run(c.name, func(t *testing.T) { + opt, err := FEN(c.fen) + if err != nil { + t.Fatalf("FEN decode: %v", err) + } + // Two independent positions with their own *Board: cow advances + // immutably via Update (which copies the board each call), while + // inplace mutates and restores via make/unmakeMove. + cow := NewGame(opt).Position() + opt2, err := FEN(c.fen) + if err != nil { + t.Fatalf("FEN decode (inplace): %v", err) + } + inplace := NewGame(opt2).Position() + walkLockstep(t, cow, inplace, depth) + }) + } +} + +func walkLockstep(t *testing.T, cow, inplace *Position, depth int) { + visitLegalMoves(cow, generateLegalOnly, func(m Move) bool { + nextCow := cow.Update(m) + undo := inplace.makeMove(m) + + if nextCow.String() != inplace.String() { + t.Errorf("FEN drift after %s at remaining depth %d:\n Update : %s\n makeMove: %s", + m, depth, nextCow.String(), inplace.String()) + inplace.unmakeMove(undo) + return true // stop iterating this node + } + + // The incremental hash must equal a full recompute on both paths: + // Update via applyMove (which now computes the hash itself), and + // makeMove via the same applyMove. A drift here would corrupt + // repetition detection downstream. + if got, want := nextCow.ZobristHash(), nextCow.computeHash(); got != want { + t.Errorf("cow hash drift after %s at remaining depth %d: incremental=%x recompute=%x", + m, depth, got, want) + inplace.unmakeMove(undo) + return true + } + if got, want := inplace.ZobristHash(), inplace.computeHash(); got != want { + t.Errorf("inplace hash drift after %s at remaining depth %d: incremental=%x recompute=%x", + m, depth, got, want) + inplace.unmakeMove(undo) + return true + } + + if depth > 1 { + walkLockstep(t, nextCow, inplace, depth-1) + } + inplace.unmakeMove(undo) + return false + }) +} + +// TestUpdatePreservesCastleRightsWithoutAllocating guards the alloc-free +// fast path in updateCastleRights: a move that touches no castle square must +// produce a Position with unchanged CastleRights and no string allocation. +func TestUpdatePreservesCastleRightsWithoutAllocating(t *testing.T) { + pos, err := decodeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1") + if err != nil { + t.Fatal(err) + } + e2e4 := Move{s1: E2, s2: E4} + + if got := pos.Update(e2e4).CastleRights().String(); got != "KQkq" { + t.Fatalf("post-move rights = %q, want KQkq", got) + } + allocs := testing.AllocsPerRun(100, func() { + _ = pos.Update(e2e4) + }) + if allocs != 1 { + t.Fatalf("Update allocated %.0f times, want 1", allocs) + } +} + +// TestApplyMoveUpdatesHashIncrementally pins down the invariant the cursor +// path (makeMove / unmakeMove) relies on: after applyMove mutates pos in +// place, pos.hash must equal a full recompute. Without this, any caller that +// advances a Position via makeMove instead of Update observes a stale hash, +// which silently breaks repetition detection (numOfRepetitions walks the +// history and compares ZobristHash values). +// +// The check runs on every legal move from a varied set of positions so a +// regression in any hash-affecting branch (castle rights, en passant, +// capture, promotion, check) fails loudly here. +func TestApplyMoveUpdatesHashIncrementally(t *testing.T) { + fens := []string{ + "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1", + "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1", + "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1", + "rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8", + } + for _, fen := range fens { + opt, err := FEN(fen) + if err != nil { + t.Fatalf("FEN decode %q: %v", fen, err) + } + root := NewGame(opt).Position() + visitLegalMoves(root, generateLegalOnly, func(m Move) bool { + pos := root.copy() + pos.makeMove(m) + if got, want := pos.ZobristHash(), pos.computeHash(); got != want { + t.Errorf("hash drift after %s from %q: incremental=%x recompute=%x", + m, fen, got, want) + } + return false + }) + } +} + +// TestCursorUndoRoundTrip walks the game tree with the cursor's slim +// make/unmake pair and asserts that unmakeMoveCursor restores the exact +// pre-move position — FEN and hash — at every node. This is the lockstep +// guarantee for board.unapply's reversal of promotion, en passant, and +// castling effects. +func TestCursorUndoRoundTrip(t *testing.T) { + fens := []string{ + "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1", + "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1", + "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1", + "rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8", + "r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - - 0 10", + } + for _, fen := range fens { + pos, err := decodeFEN(fen) + if err != nil { + t.Fatalf("FEN decode: %v", err) + } + var walk func(p *Position, depth int) + walk = func(p *Position, depth int) { + if depth == 0 { + return + } + preFEN := p.String() + preHash := p.ZobristHash() + for _, m := range p.ValidMoves() { + u := p.makeMoveCursor(m) + walk(p, depth-1) + p.unmakeMoveCursor(m, u) + if got := p.String(); got != preFEN { + t.Fatalf("fen %s move %v: after unmake got %s, want %s", fen, m, got, preFEN) + } + if got := p.ZobristHash(); got != preHash { + t.Fatalf("fen %s move %v: hash drift after unmake", fen, m) + } + } + } + walk(pos, 3) + } +} diff --git a/move_generation_test.go b/move_generation_test.go new file mode 100644 index 00000000..3fbc6b67 --- /dev/null +++ b/move_generation_test.go @@ -0,0 +1,324 @@ +package chess_test + +import ( + "sort" + "testing" + + "github.com/corentings/chess/v3" +) + +func positionFromFEN(t *testing.T, fen string) *chess.Position { + t.Helper() + opt, err := chess.FEN(fen) + if err != nil { + t.Fatalf("FEN decode: %v", err) + } + return chess.NewGame(opt).Position() +} + +func findMoveByString(moves []chess.Move, want string) (chess.Move, bool) { + for _, move := range moves { + if move.String() == want { + return move, true + } + } + return chess.Move{}, false +} + +func requireMove(t *testing.T, moves []chess.Move, want string) chess.Move { + t.Helper() + move, ok := findMoveByString(moves, want) + if !ok { + t.Fatalf("expected move %s", want) + } + return move +} + +func TestPositionStatus(t *testing.T) { + tests := []struct { + name string + fen string + want chess.Method + }{ + {"starting_position", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", chess.NoMethod}, + {"stalemate", "7k/5K2/6Q1/8/8/8/8/8 b - - 0 1", chess.Stalemate}, + {"checkmate", "7k/5K2/7Q/8/8/8/8/8 b - - 0 1", chess.Checkmate}, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + pos := positionFromFEN(t, tt.fen) + if got := pos.Status(); got != tt.want { + t.Fatalf("Status() = %s, want %s", got, tt.want) + } + }) + } +} + +func TestPositionStatusIsStableAcrossRepeatedCallsAndUpdates(t *testing.T) { + checkmate := positionFromFEN(t, "7k/5K2/7Q/8/8/8/8/8 b - - 0 1") + if got := checkmate.Status(); got != chess.Checkmate { + t.Fatalf("first Status() = %s, want %s", got, chess.Checkmate) + } + if got := checkmate.Status(); got != chess.Checkmate { + t.Fatalf("second Status() = %s, want %s", got, chess.Checkmate) + } + + start := chess.NewGame().Position() + move := requireMove(t, start.ValidMoves(), "e2e4") + next := start.Update(move) + if got := start.Status(); got != chess.NoMethod { + t.Fatalf("original Status() after Update = %s, want %s", got, chess.NoMethod) + } + if got := next.Status(); got != chess.NoMethod { + t.Fatalf("updated Status() = %s, want %s", got, chess.NoMethod) + } +} + +func TestMoveGenerationTags(t *testing.T) { + tests := []struct { + name string + fen string + move string + wantTags []chess.MoveTag + noTags []chess.MoveTag + }{ + { + name: "queen_side_castle", + fen: "r3kb1r/p2nqppp/5n2/1B2p1B1/4P3/1Q6/PPP2PPP/R3K2R b KQkq - 1 12", + move: "e8c8", + wantTags: []chess.MoveTag{chess.QueenSideCastle}, + }, + { + name: "king_side_castle_with_check", + fen: "r4b1r/ppp3pp/8/4p3/2Pq4/3P4/PP2QPPP/2k1K2R w K - 0 18", + move: "e1g1", + wantTags: []chess.MoveTag{chess.KingSideCastle, chess.Check}, + }, + { + name: "capture", + fen: "8/7p/3k2p1/8/2p2P2/R5bP/6K1/4r3 w - - 0 44", + move: "g2g3", + wantTags: []chess.MoveTag{chess.Capture}, + }, + { + name: "en_passant_with_check", + fen: "r3k2r/pbppqpb1/1pn3p1/7p/1N2pPn1/1PP4N/PB1P2PP/2QRKR2 b kq f3 0 1", + move: "e4f3", + wantTags: []chess.MoveTag{chess.EnPassant, chess.Check}, + }, + { + name: "quiet_move", + fen: "8/7p/3k2p1/8/2p2P2/R5KP/8/4r3 b - - 0 44", + move: "d6d5", + noTags: []chess.MoveTag{chess.Capture, chess.EnPassant, chess.Check, chess.KingSideCastle, chess.QueenSideCastle}, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + pos := positionFromFEN(t, tt.fen) + move := requireMove(t, pos.ValidMoves(), tt.move) + for _, tag := range tt.wantTags { + if !move.HasTag(tag) { + t.Errorf("%s missing tag %v", tt.move, tag) + } + } + for _, tag := range tt.noTags { + if move.HasTag(tag) { + t.Errorf("%s unexpectedly has tag %v", tt.move, tag) + } + } + }) + } +} + +func TestPromotionCheckTags(t *testing.T) { + pos := positionFromFEN(t, "k7/4P3/8/8/8/8/8/K7 w - - 0 1") + moves := pos.ValidMoves() + + tests := []struct { + move string + wantCheck bool + }{ + {"e7e8q", true}, + {"e7e8r", true}, + {"e7e8b", false}, + {"e7e8n", false}, + } + for _, tt := range tests { + t.Run(tt.move, func(t *testing.T) { + move := requireMove(t, moves, tt.move) + if got := move.HasTag(chess.Check); got != tt.wantCheck { + t.Fatalf("%s Check = %v, want %v", tt.move, got, tt.wantCheck) + } + }) + } +} + +func TestUnsafeMoves(t *testing.T) { + tests := []struct { + name string + fen string + want []string + count int + }{ + { + name: "starting_position", + fen: "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + count: 0, + }, + { + name: "pinned_knight", + fen: "4k3/8/8/8/1b6/2N5/8/4K3 w - - 0 1", + count: 8, + }, + { + name: "king_walks_into_check", + fen: "4r2k/8/8/8/8/8/8/4K3 w - - 0 1", + want: []string{"e1e2"}, + count: 1, + }, + { + name: "king_adjacent_rook_attacks", + fen: "8/8/8/8/8/3r4/8/4K2k w - - 0 1", + want: []string{"e1d1", "e1d2"}, + count: 2, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + pos := positionFromFEN(t, tt.fen) + moves := pos.UnsafeMoves() + if len(moves) != tt.count { + t.Fatalf("UnsafeMoves() returned %d moves, want %d", len(moves), tt.count) + } + for _, want := range tt.want { + requireMove(t, moves, want) + } + }) + } +} + +func TestLegalMovesInCheckScenarios(t *testing.T) { + t.Run("pinned_rook_stays_on_pin_ray", func(t *testing.T) { + pos := positionFromFEN(t, "k3r3/8/8/8/8/8/4R3/4K3 w - - 0 1") + got := moveStringsFrom(pos.ValidMoves(), chess.E2) + want := []string{"e2e3", "e2e4", "e2e5", "e2e6", "e2e7", "e2e8"} + sort.Strings(want) + if !equalStrings(got, want) { + t.Fatalf("pinned rook moves = %v, want %v", got, want) + } + }) + + t.Run("single_check_allows_capture_block_or_king_move", func(t *testing.T) { + pos := positionFromFEN(t, "k3r3/8/8/8/8/8/R7/4K3 w - - 0 1") + got := moveStrings(pos.ValidMoves()) + want := []string{"a2e2", "e1d1", "e1d2", "e1f1", "e1f2"} + sort.Strings(want) + if !equalStrings(got, want) { + t.Fatalf("single-check legal moves = %v, want %v", got, want) + } + }) + + t.Run("double_check_only_king_moves", func(t *testing.T) { + pos := positionFromFEN(t, "rnb1kbnr/pppp2pp/5N2/6pQ/8/8/PPPPPPPP/RNB1KB1R b KQkq - 0 1") + for _, move := range pos.ValidMoves() { + if move.S1() != chess.E8 { + t.Fatalf("double check generated non-king move %s", move) + } + } + }) + + t.Run("king_move_escapes_check", func(t *testing.T) { + pos := positionFromFEN(t, "4k3/8/8/8/8/8/8/4R2K b - - 0 1") + requireMove(t, pos.ValidMoves(), "e8d8") + }) + + t.Run("discovered_check_tag", func(t *testing.T) { + pos := positionFromFEN(t, "4k3/8/8/8/4N3/8/8/4R1K1 w - - 0 1") + for _, move := range pos.ValidMoves() { + if move.S1() == chess.E4 && move.HasTag(chess.Check) { + return + } + } + t.Fatal("expected at least one knight move from e4 with a discovered check tag") + }) + + t.Run("en_passant_discovered_check", func(t *testing.T) { + pos := positionFromFEN(t, "4r3/8/8/8/4p3/8/3P4/4K1k1 w - - 0 1") + d2d4 := requireMove(t, pos.ValidMoves(), "d2d4") + next := pos.Update(d2d4) + for _, move := range next.ValidMoves() { + if move.HasTag(chess.EnPassant) && move.HasTag(chess.Check) { + return + } + } + t.Fatal("expected en passant move with discovered check tag") + }) + + t.Run("en_passant_cannot_expose_king_to_rook", func(t *testing.T) { + pos := positionFromFEN(t, "4k3/8/8/r2pP2K/8/8/8/8 w - d6 0 1") + if _, ok := findMoveByString(pos.ValidMoves(), "e5d6"); ok { + t.Fatal("en passant exposing the king to a rook must not be legal") + } + if _, ok := findMoveByString(pos.UnsafeMoves(), "e5d6"); !ok { + t.Fatal("UnsafeMoves should report the illegal en passant candidate") + } + }) +} + +func TestSlidingPieceLegalMovesWithBlockers(t *testing.T) { + tests := []struct { + name string + fen string + from chess.Square + want []string + }{ + { + name: "rook_rank_and_file_blockers", + fen: "4k3/8/3p4/8/1P1R1p2/8/3P4/4K3 w - - 0 1", + from: chess.D4, + want: []string{"d4c4", "d4e4", "d4f4", "d4d3", "d4d5", "d4d6"}, + }, + { + name: "bishop_diagonal_blockers", + fen: "4k3/8/1P3p2/8/3B4/8/1p3P2/4K3 w - - 0 1", + from: chess.D4, + want: []string{"d4e5", "d4f6", "d4c5", "d4e3", "d4c3", "d4b2"}, + }, + { + name: "queen_combined_blockers", + fen: "4k3/8/1P1p1p2/8/1P1Q1p2/8/1p1P1P2/4K3 w - - 0 1", + from: chess.D4, + want: []string{ + "d4c4", "d4e4", "d4f4", "d4d3", "d4d5", "d4d6", + "d4e5", "d4f6", "d4c5", "d4e3", "d4c3", "d4b2", + }, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + pos := positionFromFEN(t, tt.fen) + got := moveStringsFrom(pos.ValidMoves(), tt.from) + want := append([]string(nil), tt.want...) + sort.Strings(want) + if !equalStrings(got, want) { + t.Fatalf("moves from %s = %v, want %v", tt.from, got, want) + } + }) + } +} + +func moveStringsFrom(moves []chess.Move, from chess.Square) []string { + out := make([]string, 0, len(moves)) + for _, move := range moves { + if move.S1() == from { + out = append(out, move.String()) + } + } + sort.Strings(out) + return out +} diff --git a/move_test.go b/move_test.go index 73e5f043..ab2299e0 100644 --- a/move_test.go +++ b/move_test.go @@ -2,6 +2,7 @@ package chess import ( "log" + "reflect" "testing" ) @@ -191,7 +192,7 @@ var ( ) func unsafeFEN(s string) *Position { - pos, err := decodeFEN(s) + pos, err := decodeFENUnsafe(s) if err != nil { log.Fatal(err) } @@ -231,7 +232,7 @@ func TestPositionUpdates(t *testing.T) { t.Fatalf("expected move %s %v to be valid", mt.m, mt.m.tags) } - postPos := mt.pos.Update(mt.m) + postPos := mt.pos.Update(*mt.m) if postPos.String() != mt.postPos.String() { t.Fatalf("starting from board \n%s%s\n after move %s\n expected board to be %s\n%s\n but was %s\n%s\n", mt.pos.String(), @@ -246,82 +247,8 @@ func TestPositionUpdates(t *testing.T) { } } -type perfTest struct { - pos *Position - nodesPerDepth []int -} - -/* https://www.chessprogramming.org/Perft_Results */ -var perfResults = []perfTest{ - {pos: unsafeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"), nodesPerDepth: []int{ - 20, 400, 8902, 197281, - // 4865609, 119060324, 3195901860, 84998978956, 2439530234167, 69352859712417 - }}, - {pos: unsafeFEN("r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1"), nodesPerDepth: []int{ - 48, 2039, 97862, - // 4085603, 193690690 - }}, - {pos: unsafeFEN("8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1"), nodesPerDepth: []int{ - 14, 191, 2812, 43238, 674624, - // 11030083, 178633661 - }}, - {pos: unsafeFEN("r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1"), nodesPerDepth: []int{ - 6, 264, 9467, 422333, - // 15833292, 706045033 - }}, - {pos: unsafeFEN("r2q1rk1/pP1p2pp/Q4n2/bbp1p3/Np6/1B3NBn/pPPP1PPP/R3K2R b KQ - 0 1"), nodesPerDepth: []int{ - 6, 264, 9467, 422333, - // 15833292, 706045033 - }}, - {pos: unsafeFEN("rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8"), nodesPerDepth: []int{ - 44, 1486, 62379, - // 2103487, 89941194 - }}, - {pos: unsafeFEN("r4rk1/1pp1qppp/p1np1n2/2b1p1B1/2B1P1b1/P1NP1N2/1PP1QPPP/R4RK1 w - - 0 10"), nodesPerDepth: []int{ - 46, 2079, 89890, - // 3894594, 164075551, 6923051137, 287188994746, 11923589843526, 490154852788714 - }}, -} - -func TestPerfResults(t *testing.T) { - for _, perf := range perfResults { - countMoves(t, perf.pos, []*Position{perf.pos}, perf.nodesPerDepth, len(perf.nodesPerDepth)) - } -} - -func countMoves(t *testing.T, originalPosition *Position, positions []*Position, nodesPerDepth []int, maxDepth int) { - if len(nodesPerDepth) == 0 { - return - } - depth := maxDepth - len(nodesPerDepth) + 1 - expNodes := nodesPerDepth[0] - newPositions := make([]*Position, 0) - for _, pos := range positions { - for _, move := range pos.ValidMoves() { - newPos := pos.Update(&move) - newPositions = append(newPositions, newPos) - } - } - gotNodes := len(newPositions) - if expNodes != gotNodes { - t.Errorf("Depth: %d Expected: %d Got: %d", depth, expNodes, gotNodes) - t.Log("##############################") - t.Log("# Original position info") - t.Log("###") - t.Log(originalPosition.String()) - t.Log(originalPosition.board.Draw()) - t.Log("##############################") - t.Log("# Details in JSONL (http://jsonlines.org)") - t.Log("###") - for _, pos := range positions { - t.Logf(`{"position": "%s", "moves": %d}`, pos.String(), len(pos.ValidMoves())) - } - } - countMoves(t, originalPosition, newPositions, nodesPerDepth[1:], maxDepth) -} - func Test_SetCommentUpdatesComment(t *testing.T) { - move := &Move{} + move := &MoveNode{} move.SetComment("Initial comment") expected := "Initial comment" if move.Comments() != expected { @@ -330,7 +257,8 @@ func Test_SetCommentUpdatesComment(t *testing.T) { } func Test_SetCommentOverwritesExistingComment(t *testing.T) { - move := &Move{comments: "Old comment"} + move := &MoveNode{} + move.SetComment("Old comment") move.SetComment("New comment") expected := "New comment" if move.Comments() != expected { @@ -339,7 +267,8 @@ func Test_SetCommentOverwritesExistingComment(t *testing.T) { } func Test_SetCommentWithEmptyString(t *testing.T) { - move := &Move{comments: "Existing comment"} + move := &MoveNode{} + move.SetComment("Existing comment") move.SetComment("") expected := "" if move.Comments() != expected { @@ -349,7 +278,8 @@ func Test_SetCommentWithEmptyString(t *testing.T) { func TestAddComment(t *testing.T) { t.Run("AddCommentAppendsToExistingComment", func(t *testing.T) { - move := &Move{comments: "Initial comment. "} + move := &MoveNode{} + move.SetComment("Initial comment. ") move.AddComment("Additional comment.") expected := "Initial comment. Additional comment." if move.Comments() != expected { @@ -358,7 +288,7 @@ func TestAddComment(t *testing.T) { }) t.Run("AddCommentToEmptyComment", func(t *testing.T) { - move := &Move{} + move := &MoveNode{} move.AddComment("First comment.") expected := "First comment." if move.Comments() != expected { @@ -369,7 +299,7 @@ func TestAddComment(t *testing.T) { func TestAddCommentToStructuredComments(t *testing.T) { t.Run("AddsFirstTextBlock", func(t *testing.T) { - move := &Move{structuredComments: true} + move := &MoveNode{} move.AddComment("First comment.") blocks := move.CommentBlocks() @@ -380,7 +310,7 @@ func TestAddCommentToStructuredComments(t *testing.T) { }) t.Run("AppendsToExistingTextItem", func(t *testing.T) { - move := &Move{} + move := &MoveNode{} move.addCommentBlock(CommentBlock{Items: []CommentItem{{Kind: CommentText, Text: "First "}}}) move.AddComment("second") @@ -392,7 +322,7 @@ func TestAddCommentToStructuredComments(t *testing.T) { }) t.Run("AppendsTextAfterCommandOnlyBlock", func(t *testing.T) { - move := &Move{} + move := &MoveNode{} move.addCommentBlock(CommentBlock{Items: []CommentItem{{Kind: CommentCommand, Key: "clk", Value: "0:05:00"}}}) move.AddComment("after command") @@ -404,30 +334,50 @@ func TestAddCommentToStructuredComments(t *testing.T) { }) } -func TestNAGReturnsCorrectValue(t *testing.T) { - t.Run("NAGReturnsCorrectValue", func(t *testing.T) { - move := &Move{nag: "!!"} - expected := "!!" - if move.NAG() != expected { - t.Fatalf("expected %v but got %v", expected, move.NAG()) +func TestNAGsReturnCanonicalForm(t *testing.T) { + t.Run("NAGsReturnCanonicalForm", func(t *testing.T) { + move := &MoveNode{} + if err := move.AddNAG("!!"); err != nil { + t.Fatalf("unexpected error: %v", err) + } + expected := []string{"$3"} + if got := move.NAGs(); !reflect.DeepEqual(got, expected) { + t.Fatalf("expected %v but got %v", expected, got) } }) } -func TestSetNAGUpdatesNAG(t *testing.T) { - t.Run("SetNAGUpdatesNAG", func(t *testing.T) { - move := &Move{} - move.SetNAG("??") - expected := "??" - if move.NAG() != expected { - t.Fatalf("expected %v but got %v", expected, move.NAG()) +func TestSetNAGsNormalisesValues(t *testing.T) { + t.Run("SetNAGsNormalisesValues", func(t *testing.T) { + move := &MoveNode{} + if err := move.SetNAGs([]string{"??", "$1406"}); err != nil { + t.Fatalf("unexpected error: %v", err) + } + expected := []string{"$4", "$1406"} + if got := move.NAGs(); !reflect.DeepEqual(got, expected) { + t.Fatalf("expected %v but got %v", expected, got) } }) } +func TestSetNAGsRejectsMalformed(t *testing.T) { + move := &MoveNode{} + if err := move.AddNAG("$1"); err != nil { + t.Fatalf("setup failed: %v", err) + } + // All-or-nothing: a malformed element must leave the node unchanged. + if err := move.SetNAGs([]string{"$1", "$", "$x"}); err == nil { + t.Fatalf("expected error for malformed NAGs, got nil") + } + if got := move.NAGs(); !reflect.DeepEqual(got, []string{"$1"}) { + t.Fatalf("expected unchanged [$1] after failed set, got %v", got) + } +} + func TestGetCommand(t *testing.T) { t.Run("GetCommandReturnsValueIfExists", func(t *testing.T) { - move := &Move{command: map[string]string{"key": "value"}} + move := &MoveNode{} + move.SetCommand("key", "value") value, ok := move.GetCommand("key") if !ok || value != "value" { t.Fatalf("expected value to be 'value' and ok to be true, but got value: %v, ok: %v", value, ok) @@ -435,28 +385,29 @@ func TestGetCommand(t *testing.T) { }) t.Run("GetCommandReturnsFalseIfKeyDoesNotExist", func(t *testing.T) { - move := &Move{command: map[string]string{"key": "value"}} + move := &MoveNode{} + move.SetCommand("key", "value") _, ok := move.GetCommand("nonexistent") if ok { t.Fatalf("expected ok to be false, but got true") } }) - t.Run("GetCommandInitializesCommandMapIfNil", func(t *testing.T) { - move := &Move{} + t.Run("GetCommandDoesNotCreateAnnotations", func(t *testing.T) { + move := &MoveNode{} _, ok := move.GetCommand("key") if ok { t.Fatalf("expected ok to be false, but got true") } - if move.command == nil { - t.Fatalf("expected command map to be initialized, but it was nil") + if move.hasAnnotations() { + t.Fatalf("expected missing command lookup not to create annotations") } }) } func TestStructuredCommentCommandBranches(t *testing.T) { t.Run("SetCommandAddsFirstStructuredBlock", func(t *testing.T) { - move := &Move{structuredComments: true} + move := &MoveNode{} move.SetCommand("eval", "0.25") blocks := move.CommentBlocks() @@ -467,50 +418,99 @@ func TestStructuredCommentCommandBranches(t *testing.T) { }) t.Run("EmptyCommentBlockIsIgnored", func(t *testing.T) { - move := &Move{} + move := &MoveNode{} move.addCommentBlock(CommentBlock{}) if move.hasAnnotations() { t.Fatalf("empty comment block should not add annotations") } }) - - t.Run("LegacyCommandsBecomeCommentBlocks", func(t *testing.T) { - move := &Move{command: map[string]string{"eval": "0.25"}} - blocks := move.CommentBlocks() - if len(blocks) != 1 || len(blocks[0].Items) != 1 { - t.Fatalf("expected command-only legacy block, got %#v", blocks) - } - assertCommentItem(t, blocks[0].Items[0], CommentCommand, "", "eval", "0.25") - }) - - t.Run("EmptyLegacyAnnotationsProduceNoBlock", func(t *testing.T) { - move := &Move{} - move.rebuildLegacyCommentBlockWithCommands(nil) - if len(move.commentBlocks) != 0 { - t.Fatalf("expected no comment blocks, got %#v", move.commentBlocks) - } - }) } func TestPlyNilAndMissingPosition(t *testing.T) { - var nilMove *Move + var nilMove *MoveNode if nilMove.Ply() != 0 { t.Fatalf("nil move should have ply 0") } - if (&Move{}).Ply() != 0 { + if (&MoveNode{}).Ply() != 0 { t.Fatalf("move without position should have ply 0") } } +func TestMoveNodePositionReturnsDefensiveCopy(t *testing.T) { + g := newMoveTreeTestGame() + node := g.tree.Current() + p1 := node.Position() + p2 := node.Position() + if p1 == p2 { + t.Fatal("Position() should return a fresh copy each call") + } + p1.halfMoveClock = 999 + if p2.halfMoveClock == 999 { + t.Fatal("Position() returned aliased copies") + } +} + +// TestLCANode pins down the lowest-common-ancestor helper the cursor's +// setCurrent slow path retreats through: ancestor pairs resolve to the +// ancestor, siblings resolve to the shared parent, unrelated subtrees +// resolve to the root, and root pairs resolve to root itself. +func TestLCANode(t *testing.T) { + // Build root <- a <- b <- c, plus an unrelated subtree root <- x. + root := &MoveNode{} + a := &MoveNode{parent: root} + b := &MoveNode{parent: a} + c := &MoveNode{parent: b} + x := &MoveNode{parent: root} + root.children = []*MoveNode{a, x} + a.children = []*MoveNode{b} + b.children = []*MoveNode{c} + + cases := []struct { + name string + a, b *MoveNode + want *MoveNode + }{ + {"parent of child", a, c, a}, + {"root of descendant", root, c, root}, + {"self", b, b, b}, + {"child of parent (reversed)", c, a, a}, + {"siblings", a, x, root}, + {"cousins via root", x, c, root}, + {"root against root", root, root, root}, + } + for _, tc := range cases { + t.Run(tc.name, func(t *testing.T) { + if got := lcaNode(tc.a, tc.b); got != tc.want { + t.Fatalf("lcaNode(%v, %v) = %v, want %v", tc.a, tc.b, got, tc.want) + } + }) + } +} + func BenchmarkValidMoves(b *testing.B) { pos := unsafeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1") b.ResetTimer() - for n := 0; n < b.N; n++ { + for range b.N { pos.ValidMoves() pos.validMoves = nil } } +func BenchmarkMoveNodeChildren(b *testing.B) { + node := &MoveNode{children: make([]*MoveNode, 8)} + for b.Loop() { + _ = node.Children() + } +} + +func BenchmarkMoveNodeChildrenIter(b *testing.B) { + node := &MoveNode{children: make([]*MoveNode, 8)} + for b.Loop() { + for range node.ChildrenIter { + } + } +} + func moveIsValid(pos *Position, m *Move, useTags bool) bool { for _, move := range pos.ValidMoves() { if move.s1 == m.s1 && move.s2 == m.s2 && move.promo == m.promo { @@ -525,67 +525,101 @@ func moveIsValid(pos *Position, m *Move, useTags bool) bool { return false } -func assertMovesAreEqual(t *testing.T, m1, m2 *Move) { - if m1.parent != m2.parent { - t.Fatalf("cloned mv %s parent is not the same", m1) +func assertMoveNodesAreEqual(t *testing.T, m1, m2 *MoveNode) { + if (m1.parent == nil) != (m2.parent == nil) { + t.Fatalf("cloned mv %v parent presence differs (%v vs %v)", m1, m1.parent, m2.parent) } - if m1.position.String() != m2.position.String() { - t.Fatalf("cloned mv %s position is not the same", m1) + if m1.Position().String() != m2.Position().String() { + t.Fatalf("cloned mv %v position is not the same", m1) } - if m1.nag != m2.nag { - t.Fatalf("cloned mv %s nag is not the same", m1) + if !reflect.DeepEqual(m1.NAGs(), m2.NAGs()) { + t.Fatalf("cloned mv %v nags is not the same", m1) } - if m1.comments != m2.comments { - t.Fatalf("cloned mv %s comments is not the same", m1) + if m1.Comments() != m2.Comments() { + t.Fatalf("cloned mv %v comments is not the same", m1) } if m1.number != m2.number { - t.Fatalf("cloned mv %s number is not the same", m1) + t.Fatalf("cloned mv %v number is not the same", m1) } - if m1.tags != m2.tags { - t.Fatalf("cloned mv %s tags is not the same", m1) + if m1.move.tags != m2.move.tags { + t.Fatalf("cloned mv %v tags is not the same", m1) } - if m1.s1 != m2.s1 { - t.Fatalf("cloned mv %s s1 is not the same", m1) + if m1.move.s1 != m2.move.s1 { + t.Fatalf("cloned mv %v s1 is not the same", m1) } - if m1.s2 != m2.s2 { - t.Fatalf("cloned mv %s s2 is not the same", m1) + if m1.move.s2 != m2.move.s2 { + t.Fatalf("cloned mv %v s2 is not the same", m1) } - if m1.promo != m2.promo { - t.Fatalf("cloned mv %s s2 is not the same", m1) + if m1.move.promo != m2.move.promo { + t.Fatalf("cloned mv %v s2 is not the same", m1) } - if len(m1.command) != len(m2.command) { - t.Fatalf("cloned mv %s len(command) is not the same", m1) - } else { - for k, v1 := range m1.command { - v2, ok := m2.command[k] - if !ok || v2 != v1 { - t.Fatalf("cloned mv %s command[%v] is not the same", m1, k) - } - } + if len(m1.commentBlocks) != len(m2.commentBlocks) { + t.Fatalf("cloned mv %v len(commentBlocks) is not the same", m1) } if len(m1.children) != len(m2.children) { - t.Fatalf("cloned mv %s len(command) is not the same", m1) + t.Fatalf("cloned mv %v len(command) is not the same", m1) } else { for idx, c1 := range m1.children { c2 := m2.children[idx] - assertMovesAreEqual(t, c1, c2) + assertMoveNodesAreEqual(t, c1, c2) } } } -func TestMoveClone(t *testing.T) { +func TestMoveNodeClone(t *testing.T) { for _, mt := range validMoves { - mt.m.position = mt.pos - clonedM1 := mt.m.Clone() - assertMovesAreEqual(t, mt.m, clonedM1) + // Build a single-move tree so Position() resolves via the cursor + // (ADR-016). The cloned node must produce the same position. + tree := newMoveTree(mt.pos.copy()) + node, err := tree.addMove(*mt.m, nil) + if err != nil { + t.Fatalf("addMove: %v", err) + } + node.nags = []string{"$1"} + clonedM1 := node.clone() + // Patch tree pointer so Position() resolves on the clone side. + tree2 := newMoveTree(mt.pos.copy()) + tree2.root.children = []*MoveNode{clonedM1} + clonedM1.parent = tree2.root + tree2.setTree(clonedM1) + assertMoveNodesAreEqual(t, node, clonedM1) clonedM1.SetCommand("foo", "bar") - clonedM2 := clonedM1.Clone() - assertMovesAreEqual(t, clonedM1, clonedM2) + clonedM2 := clonedM1.clone() + tree3 := newMoveTree(mt.pos.copy()) + tree3.root.children = []*MoveNode{clonedM2} + clonedM2.parent = tree3.root + tree3.setTree(clonedM2) + assertMoveNodesAreEqual(t, clonedM1, clonedM2) clonedM1.SetCommand("foo", "bar modified") fooVal, ok := clonedM2.GetCommand("foo") if !ok || fooVal != "bar" { - t.Fatalf("cloned mv %s is not a deep copy", clonedM2) + t.Fatalf("cloned mv %v is not a deep copy", clonedM2) + } + } +} + +func TestNewMove(t *testing.T) { + m := NewMove(E2, E4) + if m.S1() != E2 || m.S2() != E4 || m.Promo() != NoPieceType || m.HasTag(Capture) || m.HasTag(Check) { + t.Fatalf("NewMove(E2, E4) = %v, want e2-e4 with no tags", m) + } + + promo := NewMove(E7, E8, Queen) + if promo.S1() != E7 || promo.S2() != E8 || promo.Promo() != Queen { + t.Fatalf("NewMove(E7, E8, Queen) = %v, want e7-e8=Q", promo) + } + + // Constructed move should match the generated legal move by identity. + pos := StartingPosition() + var found bool + for _, legal := range pos.ValidMoves() { + if legal.S1() == E2 && legal.S2() == E4 { + found = true + break } } + if !found { + t.Fatal("NewMove(E2, E4) identity did not match any legal move from the starting position") + } } diff --git a/move_text_codec.go b/move_text_codec.go new file mode 100644 index 00000000..b93aa2ba --- /dev/null +++ b/move_text_codec.go @@ -0,0 +1,377 @@ +package chess + +import ( + "errors" + "fmt" + "strings" +) + +var ( + // ErrInvalidMoveText indicates syntactically invalid or unresolvable move text. + ErrInvalidMoveText = errors.New("chess: invalid move text") + // ErrMoveTextMissingPosition indicates that a codec operation needs a position. + ErrMoveTextMissingPosition = errors.New("chess: move text requires position") + // ErrMoveTextUnsupportedRawDecode indicates that a format cannot be decoded + // without a position. + ErrMoveTextUnsupportedRawDecode = errors.New("chess: move text raw decode unsupported") + // ErrInvalidMoveTextCodec indicates an impossible codec format/policy pair. + ErrInvalidMoveTextCodec = errors.New("chess: invalid move text codec") + // ErrUnsafeMoveTextUnsupported indicates that a codec cannot be used with + // unsafe move-text insertion. + ErrUnsafeMoveTextUnsupported = errors.New("chess: unsafe move text unsupported") +) + +// MoveTextFormat identifies the concrete move text grammar handled by a codec. +type MoveTextFormat uint8 + +const ( + // MoveTextFormatSAN is strict Standard Algebraic notation. + MoveTextFormatSAN MoveTextFormat = iota + // MoveTextFormatLongAlgebraic is coordinate-expanded algebraic notation. + MoveTextFormatLongAlgebraic + // MoveTextFormatUCI is Universal Chess Interface coordinate notation. + MoveTextFormatUCI +) + +// MoveTextPolicy identifies how permissive a codec is while reading move text. +type MoveTextPolicy uint8 + +const ( + // MoveTextPolicyStrict accepts only generated canonical text. + MoveTextPolicyStrict MoveTextPolicy = iota + // MoveTextPolicyPGNImport accepts documented PGN import spellings and + // canonicalises them when writing. + MoveTextPolicyPGNImport +) + +// MoveTextCodec parses, resolves, validates, and formats move text. +// +// The zero value is the strict SAN codec returned by SAN(). +type MoveTextCodec struct { + format MoveTextFormat + policy MoveTextPolicy +} + +// RawMoveText is unclassified move data decoded without a board position. +type RawMoveText struct { + from Square + to Square + promotion PieceType + null bool +} + +// Move returns the raw move as a Move without legality-derived tags. +func (m RawMoveText) Move() Move { + if m.null { + return NewNullMove() + } + return Move{s1: m.from, s2: m.to, promo: m.promotion} +} + +// From returns the raw origin square. +func (m RawMoveText) From() Square { + return m.from +} + +// To returns the raw destination square. +func (m RawMoveText) To() Square { + return m.to +} + +// Promotion returns the raw promotion piece type. +func (m RawMoveText) Promotion() PieceType { + return m.promotion +} + +// Null reports whether the raw move is a null move. +func (m RawMoveText) Null() bool { + return m.null +} + +// SAN returns the strict Standard Algebraic notation codec. +func SAN() MoveTextCodec { + return MoveTextCodec{} +} + +// PGNImportSAN returns the permissive SAN codec used by PGN import. +func PGNImportSAN() MoveTextCodec { + return MoveTextCodec{ + format: MoveTextFormatSAN, + policy: MoveTextPolicyPGNImport, + } +} + +// LongAlgebraic returns the coordinate-expanded algebraic notation codec. +func LongAlgebraic() MoveTextCodec { + return MoveTextCodec{format: MoveTextFormatLongAlgebraic} +} + +// UCI returns the Universal Chess Interface coordinate notation codec. +func UCI() MoveTextCodec { + return MoveTextCodec{format: MoveTextFormatUCI} +} + +// Format returns the codec's move text format. +func (c MoveTextCodec) Format() MoveTextFormat { + return c.format +} + +// Policy returns the codec's parsing policy. +func (c MoveTextCodec) Policy() MoveTextPolicy { + return c.policy +} + +// String implements fmt.Stringer. +func (c MoveTextCodec) String() string { + switch c { + case SAN(): + return "SAN" + case PGNImportSAN(): + return "PGNImportSAN" + case LongAlgebraic(): + return "LongAlgebraic" + case UCI(): + return "UCI" + default: + return "InvalidMoveTextCodec" + } +} + +// Encode formats a move from the supplied position. Tag-dependent suffixes +// (check, capture, disambiguation) are recomputed from the resulting position +// rather than trusted from the input move; Decode returns already-tagged +// moves from the legal-move generator and does not recompute. +func (c MoveTextCodec) Encode(pos *Position, m Move) (string, error) { + if err := c.validate(); err != nil { + return "", err + } + + switch c.format { + case MoveTextFormatSAN: + if m.HasTag(Null) { + return "Z0", nil + } + if pos == nil { + return "", ErrMoveTextMissingPosition + } + tag, _ := newLegality(pos, generateLegalAnnotated).legal(m) + m.tags = tag + return algebraicNotation{}.Encode(pos, m), nil + case MoveTextFormatLongAlgebraic: + if m.HasTag(Null) { + return "0000", nil + } + if pos == nil { + return "", ErrMoveTextMissingPosition + } + tag, _ := newLegality(pos, generateLegalAnnotated).legal(m) + m.tags = tag + return longAlgebraicNotation{}.Encode(pos, m), nil + case MoveTextFormatUCI: + return uciNotation{}.Encode(pos, m), nil + default: + return "", ErrInvalidMoveTextCodec + } +} + +// Decode resolves move text against the supplied position. +func (c MoveTextCodec) Decode(pos *Position, s string) (Move, error) { + if err := c.validate(); err != nil { + return Move{}, err + } + if pos == nil { + return Move{}, ErrMoveTextMissingPosition + } + + var ( + move Move + err error + ) + switch c.format { + case MoveTextFormatSAN: + if c.policy == MoveTextPolicyPGNImport { + s = normaliseImportSAN(s) + } + // resolveSANMove already guarantees legality; no validatePositionMove needed. + move, err = decodeSANText(pos, s, c.policy == MoveTextPolicyStrict) + case MoveTextFormatLongAlgebraic: + // resolveSANMove already guarantees legality; no validatePositionMove needed. + move, err = longAlgebraicNotation{}.Decode(pos, s) + case MoveTextFormatUCI: + move, err = uciNotation{}.Decode(pos, s) + if err == nil && !move.HasTag(Null) { + err = validatePositionMove(pos, move) + } + default: + return Move{}, ErrInvalidMoveTextCodec + } + if err != nil { + return Move{}, fmt.Errorf("%w: %w", ErrInvalidMoveText, err) + } + return move, nil +} + +// DecodeRaw decodes fully specified move text without a position. +func (c MoveTextCodec) DecodeRaw(s string) (RawMoveText, error) { + if err := c.validate(); err != nil { + return RawMoveText{}, err + } + + switch c.format { + case MoveTextFormatUCI: + return decodeRawUCI(s) + case MoveTextFormatLongAlgebraic: + return decodeRawLongAlgebraic(s) + default: + return RawMoveText{}, ErrMoveTextUnsupportedRawDecode + } +} + +// ValidateSyntax reports whether text matches the codec grammar without +// checking move legality. +func (c MoveTextCodec) ValidateSyntax(s string) error { + if err := c.validate(); err != nil { + return err + } + + switch c.format { + case MoveTextFormatSAN: + if c.policy == MoveTextPolicyPGNImport { + s = normaliseImportSAN(s) + } + if _, err := algebraicNotationParts(s); err != nil { + return fmt.Errorf("%w: %w", ErrInvalidMoveText, err) + } + return nil + case MoveTextFormatLongAlgebraic, MoveTextFormatUCI: + _, err := c.DecodeRaw(s) + return err + default: + return ErrInvalidMoveTextCodec + } +} + +func (c MoveTextCodec) validate() error { + switch c.format { + case MoveTextFormatSAN: + if c.policy == MoveTextPolicyStrict || c.policy == MoveTextPolicyPGNImport { + return nil + } + case MoveTextFormatLongAlgebraic, MoveTextFormatUCI: + if c.policy == MoveTextPolicyStrict { + return nil + } + } + return ErrInvalidMoveTextCodec +} + +func decodeRawUCI(s string) (RawMoveText, error) { + move, err := uciNotation{}.Decode(nil, s) + if err != nil { + return RawMoveText{}, fmt.Errorf("%w: %w", ErrInvalidMoveText, err) + } + if move.HasTag(Null) { + return RawMoveText{null: true}, nil + } + return RawMoveText{ + from: move.S1(), + to: move.S2(), + promotion: move.Promo(), + }, nil +} + +func decodeRawLongAlgebraic(s string) (RawMoveText, error) { + if s == "0000" { + return RawMoveText{null: true}, nil + } + + text := strings.TrimSuffix(strings.TrimSuffix(s, "+"), "#") + if len(text) > 0 && strings.Contains(text, "x") { + text = strings.Replace(text, "x", "", 1) + } + if len(text) > 0 && strings.Contains(text, "=") { + text = strings.Replace(text, "=", "", 1) + } + if len(text) == 5 && isAlgebraicPieceLetter(text[0]) { + text = text[1:] + } + + if len(text) != 4 && len(text) != 5 { + return RawMoveText{}, fmt.Errorf("%w: invalid long algebraic move %q", ErrInvalidMoveText, s) + } + if !isSquareText(text[:2]) || !isSquareText(text[2:4]) { + return RawMoveText{}, fmt.Errorf("%w: invalid long algebraic squares %q", ErrInvalidMoveText, s) + } + + promotion := NoPieceType + if len(text) == 5 { + promotion = algebraicPromotionPiece(text[4]) + if promotion == NoPieceType { + return RawMoveText{}, fmt.Errorf("%w: invalid long algebraic promotion %q", ErrInvalidMoveText, s) + } + } + + return RawMoveText{ + from: squareFromFileRank(text[0], text[1]), + to: squareFromFileRank(text[2], text[3]), + promotion: promotion, + }, nil +} + +func normaliseImportSAN(s string) string { + if len(s) < 3 { + return s + } + + suffix := "" + for len(s) > 0 { + switch { + case strings.HasSuffix(s, "+"): + suffix = "+" + suffix + s = strings.TrimSuffix(s, "+") + case strings.HasSuffix(s, "#"): + suffix = "#" + suffix + s = strings.TrimSuffix(s, "#") + case strings.HasSuffix(s, "!"), strings.HasSuffix(s, "?"): + s = s[:len(s)-1] + case strings.HasSuffix(s, "e.p."): + s = strings.TrimSuffix(s, "e.p.") + default: + goto done + } + } + +done: + if len(s) >= 3 && s[len(s)-2] >= '1' && s[len(s)-2] <= '8' && algebraicPromotionPiece(s[len(s)-1]) != NoPieceType { + s = s[:len(s)-1] + "=" + s[len(s)-1:] + } + return s + suffix +} + +func isSquareText(s string) bool { + return len(s) == 2 && s[0] >= 'a' && s[0] <= 'h' && s[1] >= '1' && s[1] <= '8' +} + +func isAlgebraicPieceLetter(b byte) bool { + switch b { + case 'K', 'Q', 'R', 'B', 'N': + return true + default: + return false + } +} + +func algebraicPromotionPiece(b byte) PieceType { + switch b { + case 'Q': + return Queen + case 'R': + return Rook + case 'B': + return Bishop + case 'N': + return Knight + default: + return NoPieceType + } +} diff --git a/move_text_codec_test.go b/move_text_codec_test.go new file mode 100644 index 00000000..86525358 --- /dev/null +++ b/move_text_codec_test.go @@ -0,0 +1,164 @@ +package chess_test + +import ( + "errors" + "testing" + + "github.com/corentings/chess/v3" +) + +func TestMoveTextCodecZeroValueIsStrictSAN(t *testing.T) { + var zero chess.MoveTextCodec + + if zero != chess.SAN() { + t.Fatalf("zero MoveTextCodec = %#v, want SAN()", zero) + } + if got := zero.Format(); got != chess.MoveTextFormatSAN { + t.Fatalf("zero Format() = %v, want %v", got, chess.MoveTextFormatSAN) + } + if got := zero.Policy(); got != chess.MoveTextPolicyStrict { + t.Fatalf("zero Policy() = %v, want %v", got, chess.MoveTextPolicyStrict) + } + if got := zero.String(); got != "SAN" { + t.Fatalf("zero String() = %q, want %q", got, "SAN") + } +} + +func TestMoveTextCodecConstructors(t *testing.T) { + tests := []struct { + name string + codec chess.MoveTextCodec + wantFormat chess.MoveTextFormat + wantPolicy chess.MoveTextPolicy + wantString string + }{ + { + name: "SAN", + codec: chess.SAN(), + wantFormat: chess.MoveTextFormatSAN, + wantPolicy: chess.MoveTextPolicyStrict, + wantString: "SAN", + }, + { + name: "PGN import SAN", + codec: chess.PGNImportSAN(), + wantFormat: chess.MoveTextFormatSAN, + wantPolicy: chess.MoveTextPolicyPGNImport, + wantString: "PGNImportSAN", + }, + { + name: "long algebraic", + codec: chess.LongAlgebraic(), + wantFormat: chess.MoveTextFormatLongAlgebraic, + wantPolicy: chess.MoveTextPolicyStrict, + wantString: "LongAlgebraic", + }, + { + name: "UCI", + codec: chess.UCI(), + wantFormat: chess.MoveTextFormatUCI, + wantPolicy: chess.MoveTextPolicyStrict, + wantString: "UCI", + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + if got := tt.codec.Format(); got != tt.wantFormat { + t.Fatalf("Format() = %v, want %v", got, tt.wantFormat) + } + if got := tt.codec.Policy(); got != tt.wantPolicy { + t.Fatalf("Policy() = %v, want %v", got, tt.wantPolicy) + } + if got := tt.codec.String(); got != tt.wantString { + t.Fatalf("String() = %q, want %q", got, tt.wantString) + } + }) + } +} + +func TestMoveTextCodecSANEncodeDecode(t *testing.T) { + pos := chess.StartingPosition() + rawMove, err := chess.UCI().DecodeRaw("e2e4") + if err != nil { + t.Fatalf("DecodeRaw() error = %v", err) + } + staleMove := rawMove.Move() + + encoded, err := chess.SAN().Encode(pos, staleMove) + if err != nil { + t.Fatalf("Encode() error = %v", err) + } + if encoded != "e4" { + t.Fatalf("Encode() = %q, want %q", encoded, "e4") + } + + decoded, err := chess.SAN().Decode(pos, encoded) + if err != nil { + t.Fatalf("Decode() error = %v", err) + } + if decoded != staleMove { + t.Fatalf("Decode() = %v, want %v", decoded, staleMove) + } +} + +func TestMoveTextCodecRequiresPositionForResolution(t *testing.T) { + _, err := chess.SAN().Decode(nil, "e4") + if !errors.Is(err, chess.ErrMoveTextMissingPosition) { + t.Fatalf("Decode(nil) error = %v, want ErrMoveTextMissingPosition", err) + } +} + +func TestMoveTextCodecDecodeRejectsIllegalCoordinateMove(t *testing.T) { + _, err := chess.UCI().Decode(chess.StartingPosition(), "e2e5") + if !errors.Is(err, chess.ErrInvalidMoveText) { + t.Fatalf("UCI Decode() error = %v, want ErrInvalidMoveText", err) + } +} + +func TestPGNImportSANCodecAcceptsMissingPromotionEquals(t *testing.T) { + opt, err := chess.FEN("6k1/4P3/8/8/8/8/8/4K3 w - - 0 1") + if err != nil { + t.Fatalf("FEN() error = %v", err) + } + pos := chess.NewGame(opt).Position() + + if _, err := chess.SAN().Decode(pos, "e8Q"); !errors.Is(err, chess.ErrInvalidMoveText) { + t.Fatalf("strict SAN Decode() error = %v, want ErrInvalidMoveText", err) + } + + move, err := chess.PGNImportSAN().Decode(pos, "e8Q") + if err != nil { + t.Fatalf("PGNImportSAN Decode() error = %v", err) + } + encoded, err := chess.SAN().Encode(pos, move) + if err != nil { + t.Fatalf("Encode() error = %v", err) + } + if encoded != "e8=Q+" { + t.Fatalf("canonical SAN = %q, want %q", encoded, "e8=Q+") + } +} + +func TestMoveTextCodecDecodeRaw(t *testing.T) { + rawUCI, err := chess.UCI().DecodeRaw("e7e8q") + if err != nil { + t.Fatalf("UCI DecodeRaw() error = %v", err) + } + if rawUCI.From() != chess.E7 || rawUCI.To() != chess.E8 || rawUCI.Promotion() != chess.Queen { + t.Fatalf("UCI DecodeRaw() = %v-%v %v, want e7-e8 Queen", rawUCI.From(), rawUCI.To(), rawUCI.Promotion()) + } + + rawLong, err := chess.LongAlgebraic().DecodeRaw("Ne2xf4") + if err != nil { + t.Fatalf("LongAlgebraic DecodeRaw() error = %v", err) + } + if rawLong.From() != chess.E2 || rawLong.To() != chess.F4 || rawLong.Promotion() != chess.NoPieceType { + t.Fatalf("LongAlgebraic DecodeRaw() = %v-%v %v, want e2-f4 no promotion", rawLong.From(), rawLong.To(), rawLong.Promotion()) + } + + _, err = chess.SAN().DecodeRaw("Nf3") + if !errors.Is(err, chess.ErrMoveTextUnsupportedRawDecode) { + t.Fatalf("SAN DecodeRaw() error = %v, want ErrMoveTextUnsupportedRawDecode", err) + } +} diff --git a/movegen.go b/movegen.go new file mode 100644 index 00000000..67781a9b --- /dev/null +++ b/movegen.go @@ -0,0 +1,212 @@ +package chess + +import ( + "sync" +) + +type moveGenerationMode uint8 + +const ( + generateLegalAnnotated moveGenerationMode = iota + generateLegalOnly + generateUnsafeOnly +) + +// calcMoves returns all legal moves for the given position. If first is true, +// returns after finding the first legal move. This is useful for quick position +// validation. +// +// The moves are generated in the following order: +// 1. Standard piece moves and captures +// 2. Castling moves (if available) +// +// Each move is validated to ensure it doesn't leave the king in check. +func calcMoves(pos *Position, first bool) []Move { + if first { + if hasLegalMove(pos) { + return []Move{{}} + } + return nil + } + + // generate possible moves + moves := legalMovesForMode(pos, generateLegalAnnotated) + return moves +} + +func legalMovesForMode(pos *Position, mode moveGenerationMode) []Move { + moves := standardMoves(pos, false, mode) + // return moves including castles + var castles [2]Move + count := castleMovesInto(pos, &castles, mode) + moves = append(moves, castles[:count]...) + return moves +} + +// unsafeMoves returns all pseudo-legal moves that are illegal because they +// leave the moving side's king in check. +func unsafeMoves(pos *Position) []Move { + return standardMoves(pos, false, generateUnsafeOnly) +} + +// status returns the current position's Method (Checkmate, Stalemate, or +// NoMethod). +// +// The Method is determined by: +// - Whether the side to move is in check +// - Whether any legal moves exist +// +// If the position has cached valid moves in pos.validMoves, those will be +// used. Otherwise, moves will be calculated to determine the Method. +func status(pos *Position) Method { + var hasMove bool + if pos.validMoves != nil { + hasMove = len(pos.validMoves) > 0 + } else { + hasMove = hasLegalMove(pos) + } + if !pos.inCheck && !hasMove { + return Stalemate + } else if pos.inCheck && !hasMove { + return Checkmate + } + return NoMethod +} + +func hasLegalMove(pos *Position) bool { + if hasStandardMove(pos) { + return true + } + return hasCastleMove(pos) +} + +func hasStandardMove(pos *Position) bool { + return visitStandardMoves(pos, generateLegalOnly, func(Move) bool { return true }) +} + +func visitLegalMoves(pos *Position, mode moveGenerationMode, visit func(Move) bool) { + if visitStandardMoves(pos, mode, visit) { + return + } + if mode == generateUnsafeOnly { + return + } + var castles [2]Move + count := castleMovesInto(pos, &castles, mode) + for _, m := range castles[:count] { + if visit(m) { + return + } + } +} + +func visitStandardMoves(pos *Position, mode moveGenerationMode, visit func(Move) bool) bool { + var m Move + lg := newLegality(pos, mode) + + bbAllowed := ^pos.board.whiteSqs + if pos.Turn() == Black { + bbAllowed = ^pos.board.blackSqs + } + + for _, p := range allPieces { + if pos.Turn() != p.Color() { + continue + } + s1BB := pos.board.bbForPiece(p) + if s1BB == 0 { + continue + } + for s1Bits := s1BB; s1Bits != 0; s1Bits &= s1Bits - 1 { + s1 := squareFromBit(s1Bits & -s1Bits) + s2BB := bbForPossibleMoves(pos, p.Type(), s1) & bbAllowed + s2BB = lg.filter(p, s1, s2BB) + if s2BB == 0 { + continue + } + for s2Bits := s2BB; s2Bits != 0; s2Bits &= s2Bits - 1 { + s2 := squareFromBit(s2Bits & -s2Bits) + + m.s1 = s1 + m.s2 = s2 + + if (p == WhitePawn && s2.Rank() == Rank8) || (p == BlackPawn && s2.Rank() == Rank1) { + for _, pt := range promoPieceTypes { + m.promo = pt + tag, ok := lg.legal(m) + m.tags = tag + if ok == (mode != generateUnsafeOnly) && visit(m) { + return true + } + } + } else { + m.promo = 0 + tag, ok := lg.legal(m) + m.tags = tag + if ok == (mode != generateUnsafeOnly) && visit(m) { + return true + } + } + } + } + } + + return false +} + +// promoPieceTypes is an immutable array of promotion piece types. +// Treat as read-only; do not modify elements. +// +//nolint:gochecknoglobals // Immutable lookup table. +var promoPieceTypes = [4]PieceType{Queen, Rook, Bishop, Knight} + +const maxPossibleMoves = 218 // Maximum possible moves in any chess position + +// movePool is a pool of Move arrays to reduce allocations +// in the standardMoves function. +// +//nolint:gochecknoglobals // this is a sync pool +var movePool = &sync.Pool{ + New: func() any { + return &[maxPossibleMoves]Move{} + }, +} + +// standardMoves generates all standard (non-castling) legal moves for the +// current position. If first is true, returns after finding the first +// legal move. +// +// The function uses a sync.Pool of move arrays to reduce allocations. Each +// move is validated to ensure it doesn't leave the king in check. +func standardMoves(pos *Position, first bool, mode moveGenerationMode) []Move { + moves, ok := movePool.Get().(*[maxPossibleMoves]Move) + if !ok { + // Pool returned an unexpected type; allocate a fresh array rather + // than dereferencing a nil pointer below. + moves = &[maxPossibleMoves]Move{} + } + defer movePool.Put(moves) + count := 0 + + if first { + var result [1]Move + if visitStandardMoves(pos, mode, func(m Move) bool { + result[0] = m + return true + }) { + return result[:] + } + return nil + } + + visitStandardMoves(pos, mode, func(m Move) bool { + moves[count] = m + count++ + return false + }) + + // Need to copy since we're returning array to pool + result := make([]Move, count) + copy(result, moves[:count]) + return result +} diff --git a/movetree.go b/movetree.go new file mode 100644 index 00000000..ffb945c3 --- /dev/null +++ b/movetree.go @@ -0,0 +1,531 @@ +package chess + +import ( + "cmp" + "errors" + "fmt" +) + +// MoveInsertOptions contains options for inserting a move into a MoveTree. +type MoveInsertOptions struct { + // PromoteToMainLine makes the inserted or selected continuation the main line. + PromoteToMainLine bool +} + +// MoveTree owns the move topology and active cursor for a game. +// +// The root is a synthetic position node, not a move occurrence. The cursor's +// current position is tracked in pos alongside current: every navigation +// (addMove, GoForward, GoBack, Forward, Goto, Reset, setCurrent) advances pos +// via the in-place makeMoveCursor / unmakeMoveCursor pair (move_applier.go), +// with one entry in undos per level between root and current. rootPos holds +// the starting position so the cursor can be reset without re-deriving it +// from the synthetic root MoveNode. +type MoveTree struct { + root *MoveNode + current *MoveNode + rootPos *Position + pos *Position + undos []cursorUndo +} + +func newMoveTree(pos *Position) *MoveTree { + root := &MoveNode{} + t := &MoveTree{ + root: root, + current: root, + rootPos: pos, + pos: pos.copy(), + undos: nil, + } + t.setTree(root) + return t +} + +// setTree recursively patches n.tree = t on every node reachable from n. Used +// after Clone / Split where clone() copies topology but not the tree pointer. +func (t *MoveTree) setTree(n *MoveNode) { + if n == nil { + return + } + n.tree = t + for _, c := range n.children { + t.setTree(c) + } +} + +// Root returns the root position node. +func (t *MoveTree) Root() *MoveNode { + if t == nil { + return nil + } + return t.root +} + +// Current returns the active cursor node. +func (t *MoveTree) Current() *MoveNode { + if t == nil { + return nil + } + return t.current +} + +// MainLine returns the main-line move nodes, excluding the root position node. +func (t *MoveTree) MainLine() []*MoveNode { + if t == nil || t.root == nil { + return nil + } + + nodes := make([]*MoveNode, 0) + for current := t.MainChild(t.root); current != nil; current = t.MainChild(current) { + nodes = append(nodes, current) + } + return nodes +} + +// MainChild returns the main-line continuation from parent. +func (t *MoveTree) MainChild(parent *MoveNode) *MoveNode { + if parent == nil || len(parent.children) == 0 { + return nil + } + return parent.children[0] +} + +// Continuations returns all continuations from parent. +func (t *MoveTree) Continuations(parent *MoveNode) []*MoveNode { + if parent == nil { + return nil + } + return append([]*MoveNode{}, parent.children...) +} + +// Variations returns all non-main-line continuations from parent. +func (t *MoveTree) Variations(parent *MoveNode) []*MoveNode { + if parent == nil || len(parent.children) <= 1 { + return nil + } + return append([]*MoveNode{}, parent.children[1:]...) +} + +func (t *MoveTree) addMove(move Move, options *MoveInsertOptions) (*MoveNode, error) { + if t == nil || t.current == nil { + return nil, errors.New("chess: move tree has no current position") + } + options = cmp.Or(options, &MoveInsertOptions{}) + + if existing := t.findExistingMove(move); existing != nil { + if options.PromoteToMainLine { + t.promoteToMainLine(existing) + } + // If the existing Move occurrence was placed via an unsafe path that + // supplied stale tags, canonicalise the stored Move in place. The + // incoming move has the canonical tags from resolveCanonicalMove (or + // from a trusted codec on the MoveText fast path). When the + // existing occurrence already has continuations the subtree was + // computed against the old Move's position-derived state, so repair + // is unsafe; refuse and leave the tree unchanged. + if existing.move.tags != move.tags { + if len(existing.children) > 0 { + return nil, errors.New("chess: cannot canonicalise existing Move occurrence with continuations") + } + existing.move = move + } + // Advance the cursor in place rather than re-deriving the post-move + // position from existing.position. The undo record keeps undos in + // sync with the depth between root and current. + t.undos = append(t.undos, t.pos.makeMoveCursor(existing.move)) + t.current = existing + return existing, nil + } + + node := &MoveNode{move: move, parent: t.current, tree: t} + // Advance the cursor in place; t.pos is now post-move. The node carries + // no per-node position — readers route through the cursor via + // MoveNode.Position() (ADR-016). + t.undos = append(t.undos, t.pos.makeMoveCursor(move)) + + if options.PromoteToMainLine { + t.current.children = append(t.current.children, nil) + copy(t.current.children[1:], t.current.children[:len(t.current.children)-1]) + t.current.children[0] = node + } else { + t.current.children = append(t.current.children, node) + } + t.current = node + return node, nil +} + +// AddVariation validates and appends move as a variation from parent. The +// cursor is saved and restored so the caller's active position is unchanged. +func (t *MoveTree) AddVariation(parent *MoveNode, move Move) (*MoveNode, error) { + if t == nil || t.root == nil { + return nil, errors.New("chess: move tree has no root position") + } + if parent == nil { + parent = t.root + } + // Resolve parent's position via the cursor — variations attach to an + // arbitrary node, not the cursor's current node, so we navigate. Save + // and restore the cursor so the caller's active position is unchanged. + defer t.setCurrent(t.current) + if !t.Goto(parent) { + return nil, errors.New("chess: variation parent is not reachable from cursor") + } + if t.pos == nil { + return nil, errors.New("chess: variation parent has no position") + } + canonical, err := resolveCanonicalMove(t.pos, move) + if err != nil { + return nil, err + } + for _, sibling := range parent.children { + if !sameMove(sibling.move, canonical) { + continue + } + if sibling.move.tags != canonical.tags { + if len(sibling.children) > 0 { + return nil, errors.New("chess: cannot canonicalise existing Move occurrence with continuations") + } + sibling.move = canonical + } + return sibling, nil + } + return t.addVariationUnchecked(parent, canonical), nil +} + +func (t *MoveTree) addVariationUnchecked(parent *MoveNode, move Move) *MoveNode { + if parent == nil { + parent = t.root + } + node := &MoveNode{move: move, parent: parent, tree: t} + parent.children = append(parent.children, node) + return node +} + +// GoBack moves the active cursor to its parent. +func (t *MoveTree) GoBack() bool { + if t == nil || t.current == nil || t.current.parent == nil { + return false + } + if len(t.undos) == 0 { + // Cursor invariant broken; refuse to advance rather than panic. + return false + } + undo := t.undos[len(t.undos)-1] + t.undos = t.undos[:len(t.undos)-1] + // The undo at the top of the stack reverses the move that led to + // current; read it before current retreats. + t.pos.unmakeMoveCursor(t.current.move, undo) + t.current = t.current.parent + return true +} + +// GoForward moves the active cursor to the main continuation. +func (t *MoveTree) GoForward() bool { + if t == nil || t.current == nil || len(t.current.children) == 0 { + return false + } + child := t.current.children[0] + t.undos = append(t.undos, t.pos.makeMoveCursor(child.move)) + t.current = child + return true +} + +// NavigateToMainLine moves the active cursor to the first main-line move. +func (t *MoveTree) NavigateToMainLine() { + if t == nil || t.root == nil { + return + } + t.resetCursor() + if len(t.root.children) == 0 { + return + } + t.GoForward() +} + +// Peek returns the live [Position] at the tree's active cursor without copying. +// The returned pointer aliases the tree's internal state and is valid only +// until the next cursor move (GoForward, GoBack, Forward, Goto, Reset, +// AddVariation, or any move pushed onto the tree). Callers MUST NOT mutate +// it; mutation corrupts the cursor and every subsequent read in the library, +// including legal-move generation and repetition detection. +// +// For a snapshot you can retain or mutate, use [MoveNode.Position] (a +// defensive copy at a node) or [Game.Position] (a defensive copy of the +// current position). Both copy. +// +// Returns nil if t is nil or has no position. +func (t *MoveTree) Peek() *Position { + if t == nil { + return nil + } + return t.pos +} + +// Forward advances the cursor to the idx-th child of the current node. +// Forward(0) is equivalent to [MoveTree.GoForward] (main-line continuation). +// Returns true on success; false if t is nil, the current node has no +// children, or idx is out of range. +func (t *MoveTree) Forward(idx int) bool { + if t == nil || t.current == nil { + return false + } + if idx < 0 || idx >= len(t.current.children) { + return false + } + // Route through setCurrent so the direct-child fast path owns the + // makeMove/undo append invariant. Forward(0) then matches GoForward. + t.setCurrent(t.current.children[idx]) + return true +} + +// Goto jumps the cursor to the given node. Returns true if the cursor moved. +// Returns false if t is nil, node is nil, or node belongs to a different tree. +// Goto uses the same fast paths as internal cursor navigation: direct child, +// LCA walk, and full replay-from-root (see [MoveTree.setCurrent]). +func (t *MoveTree) Goto(node *MoveNode) bool { + if t == nil || node == nil { + return false + } + if node.tree != t { + return false + } + t.setCurrent(node) + return true +} + +// Reset returns the cursor to the synthetic root, restoring the starting +// position. Safe to call on a nil tree. +func (t *MoveTree) Reset() { + if t == nil { + return + } + t.resetCursor() +} + +// Lines returns every root-to-leaf line in the tree. +func (t *MoveTree) Lines() [][]*MoveNode { + if t == nil || t.root == nil { + return nil + } + var paths [][]*MoveNode + for _, child := range t.root.children { + paths = append(paths, collectPaths(child)...) + } + return paths +} + +// Clone returns a deep copy of the move tree with the cursor preserved. +func (t *MoveTree) Clone() *MoveTree { + if t == nil || t.root == nil { + return nil + } + ret := &MoveTree{ + root: t.root.clone(), + rootPos: t.rootPos.copy(), + } + // Patch tree back-pointers on the freshly cloned topology. + ret.setTree(ret.root) + ret.pos = ret.rootPos.copy() + ret.undos = nil + ret.current = ret.root + // Find the cloned equivalent of the original cursor and replay forward + // so pos / undos match the new current. + var target *MoveNode + if t.current == nil || t.current == t.root { + target = ret.root + } else { + target = findClonedMove(t.root, ret.root, t.current) + if target == nil { + target = ret.root + } + } + ret.setCurrent(target) + return ret +} + +func (t *MoveTree) position() *Position { + if t == nil || t.pos == nil { + return nil + } + return t.pos +} + +func (t *MoveTree) setRootPosition(pos *Position) { + if t == nil || t.root == nil { + return + } + t.rootPos = pos + t.resetCursor() +} + +// resetCursor rewinds pos to rootPos and clears the undo stack. current lands +// on the synthetic root, ready for addMove / GoForward to push forward again. +func (t *MoveTree) resetCursor() { + if t == nil { + return + } + t.pos = t.rootPos.copy() + t.undos = t.undos[:0] + t.current = t.root +} + +func (t *MoveTree) setCurrent(node *MoveNode) { + if t == nil { + return + } + if node == nil { + node = t.root + } + if node == t.current { + return + } + // Direct child of current: advance one step. This is the hot path for + // linear parsing (PGN addMove, GoForward after a findExisting). + if node.parent == t.current { + t.undos = append(t.undos, t.pos.makeMoveCursor(node.move)) + t.current = node + return + } + // Anything else — ancestor, sibling subtree, root: retreat to the lowest + // common ancestor by popping undos, then advance along node's chain. + // This is the variation-entry/exit hot path in PGN parsing; the LCA turns + // an O(root-depth) reset+replay (with a rootPos.copy allocation) into an + // O(distance) walk with no allocation. + ancestor := lcaNode(t.current, node) + for t.current != ancestor { + if !t.GoBack() { + break + } + } + t.replayToFrom(node, ancestor) + t.current = node +} + +// replayToFrom advances pos from stop's position to node's, pushing one undo +// per move along the stop-to-node chain. Recursive so the chain stays on the +// call stack (no heap alloc per variation). +func (t *MoveTree) replayToFrom(node, stop *MoveNode) { + if node == nil || node == stop { + return + } + t.replayToFrom(node.parent, stop) + t.undos = append(t.undos, t.pos.makeMoveCursor(node.move)) +} + +// nodeDepth returns the number of moves between the synthetic root and n. +func nodeDepth(n *MoveNode) int { + d := 0 + for cur := n; cur != nil && cur.parent != nil; cur = cur.parent { + d++ + } + return d +} + +// lcaNode returns the lowest common ancestor of a and b — the root at worst +// for same-tree nodes (the only kind setCurrent mixes, per ADR-016). +// Pointer-walk only: no position mutation, no allocation. +func lcaNode(a, b *MoveNode) *MoveNode { + da, db := nodeDepth(a), nodeDepth(b) + for da > db { + a = a.parent + da-- + } + for db > da { + b = b.parent + db-- + } + for a != nil && b != nil && a != b { + a = a.parent + b = b.parent + } + return a +} + +func (t *MoveTree) findExistingMove(move Move) *MoveNode { + if t == nil || t.current == nil { + return nil + } + for _, child := range t.current.children { + if sameMove(child.move, move) { + return child + } + } + return nil +} + +func (t *MoveTree) promoteToMainLine(move *MoveNode) { + if move == nil || move.parent == nil { + return + } + children := move.parent.children + for i, child := range children { + if child == move { + for ; i > 0; i-- { + children[i] = children[i-1] + } + children[0] = move + return + } + } +} + +func sameMove(a, b Move) bool { + return a.s1 == b.s1 && a.s2 == b.s2 && a.promo == b.promo +} + +func validatePositionMove(pos *Position, move Move) error { + if pos == nil { + return errors.New("chess: no current position") + } + if move.HasTag(Null) { + return nil + } + for _, validMove := range pos.ValidMovesUnsafe() { + if sameMove(validMove, move) { + return nil + } + } + return fmt.Errorf("move %s is not valid for the current position", move.String()) +} + +// collectPaths returns all paths from the given move to each leaf node. +// Each path is represented as a slice of *MoveNode, starting with the given node +// and ending with a leaf (a move with no children). +func collectPaths(node *MoveNode) [][]*MoveNode { + if node == nil { + return nil + } + // If leaf, return a single path containing this node + if len(node.children) == 0 { + return [][]*MoveNode{{node}} + } + // Otherwise, collect paths from each child and prepend this node + var paths [][]*MoveNode + for _, c := range node.children { + childPaths := collectPaths(c) + for _, p := range childPaths { + path := append([]*MoveNode{node}, p...) + paths = append(paths, path) + } + } + return paths +} + +func findClonedMove(original, clone, target *MoveNode) *MoveNode { + if original == nil || clone == nil || target == nil { + return nil + } + if original == target { + return clone + } + for i, child := range original.children { + if i >= len(clone.children) { + return nil + } + if found := findClonedMove(child, clone.children[i], target); found != nil { + return found + } + } + return nil +} diff --git a/movetree_test.go b/movetree_test.go new file mode 100644 index 00000000..45b22bef --- /dev/null +++ b/movetree_test.go @@ -0,0 +1,343 @@ +package chess + +import ( + "testing" +) + +func mustSAN(pos *Position, san string) *Move { + m, err := SAN().Decode(pos, san) + if err != nil { + panic(err) + } + return &m +} + +func newMoveTreeTestGame() *Game { + g := NewGame() + g.MoveText("e4", SAN(), nil) + g.MoveText("e5", SAN(), nil) + g.MoveText("Nf3", SAN(), nil) + return g +} + +func TestMoveTreePeekReturnsStartingPosition(t *testing.T) { + g := NewGame() + if got := g.tree.Peek(); got == nil { + t.Fatal("Peek on nil-active game returned nil") + } + if got := g.tree.Peek().String(); got != StartingPosition().String() { + t.Fatalf("Peek = %q, want starting position", got) + } +} + +func TestMoveTreeGoForwardAdvances(t *testing.T) { + g := newMoveTreeTestGame() + g.tree.Reset() + if !g.tree.GoForward() { + t.Fatal("GoForward from root failed") + } + want := StartingPosition().Update(*mustSAN(StartingPosition(), "e4")).String() + if got := g.tree.Peek().String(); got != want { + t.Fatalf("after GoForward, Peek = %q, want post-e4 %q", got, want) + } +} + +func TestMoveTreeBackAndForwardRoundTrip(t *testing.T) { + g := newMoveTreeTestGame() + leaf := g.tree.Peek().String() + + for i := range 3 { + if !g.tree.GoBack() { + t.Fatalf("GoBack #%d failed", i) + } + } + if g.tree.GoBack() { + t.Fatal("GoBack from root should fail") + } + if got := g.tree.Peek().String(); got != StartingPosition().String() { + t.Fatalf("after 3 GoBacks, Peek = %q, want starting position", got) + } + + for i := range 3 { + if !g.tree.GoForward() { + t.Fatalf("GoForward #%d failed", i) + } + } + if got := g.tree.Peek().String(); got != leaf { + t.Fatalf("round-trip Peek = %q, want %q", got, leaf) + } +} + +func TestMoveTreeForwardIndex(t *testing.T) { + g := NewGame() + root := g.tree.Root() + a := &MoveNode{move: *mustSAN(StartingPosition(), "e4"), parent: root} + b := &MoveNode{move: *mustSAN(StartingPosition(), "d4"), parent: root} + cc := &MoveNode{move: *mustSAN(StartingPosition(), "Nf3"), parent: root} + root.children = []*MoveNode{a, b, cc} + + g.tree.Reset() + + if g.tree.Forward(3) { + t.Fatal("Forward(3) should fail (out of range)") + } + if g.tree.Forward(-1) { + t.Fatal("Forward(-1) should fail") + } + if !g.tree.Forward(1) { + t.Fatal("Forward(1) failed") + } + want := StartingPosition().Update(b.move).String() + if got := g.tree.Peek().String(); got != want { + t.Fatalf("after Forward(1), Peek = %q, want %q", got, want) + } +} + +func TestMoveTreeGotoDeepDescendant(t *testing.T) { + g := newMoveTreeTestGame() + leaf := g.tree.Current() + want := g.tree.pos.String() + g.tree.Reset() + if !g.tree.Goto(leaf) { + t.Fatal("Goto failed") + } + if got := g.tree.Peek().String(); got != want { + t.Fatalf("Goto+Peek = %q, want %q", got, want) + } +} + +func TestMoveTreeResetReturnsToRoot(t *testing.T) { + g := newMoveTreeTestGame() + g.tree.Reset() + if got := g.tree.Peek().String(); got != StartingPosition().String() { + t.Fatalf("after Reset, Peek = %q, want starting position", got) + } +} + +func TestMoveTreePeekIsLive(t *testing.T) { + g := newMoveTreeTestGame() + g.tree.Reset() + peeked := g.tree.Peek() + if peeked != g.tree.Peek() { + t.Fatal("Peek should alias the same pointer across reads with no nav") + } + g.tree.GoForward() + if peeked.String() != g.tree.Peek().String() { + t.Fatalf("Peek alias lost its live updates: aliased=%q fresh=%q", peeked.String(), g.tree.Peek().String()) + } +} + +func TestMoveTreeGotoCurrentIsNoop(t *testing.T) { + g := newMoveTreeTestGame() + leaf := g.tree.Current() + beforeUndos := len(g.tree.undos) + if !g.tree.Goto(leaf) { + t.Fatal("Goto(current) should succeed") + } + if len(g.tree.undos) != beforeUndos { + t.Fatalf("Goto(current) mutated undo stack: %d -> %d", beforeUndos, len(g.tree.undos)) + } +} + +func TestMoveTreeGotoRootViaLCA(t *testing.T) { + g := newMoveTreeTestGame() + g.tree.Reset() + if !g.tree.Goto(g.tree.Root()) { + t.Fatal("Goto(root) failed") + } + if len(g.tree.undos) != 0 { + t.Fatalf("Goto(root) left %d undos, want 0", len(g.tree.undos)) + } + if g.tree.Peek().String() != StartingPosition().String() { + t.Fatal("Goto(root) did not reset position") + } +} + +func TestMoveTreeGotoSiblingSubtree(t *testing.T) { + // Pin the LCA path through setCurrent: jump between sibling subtrees + // from the same parent. The setCurrent slow path walks to the LCA + // (the shared parent) and then advances along the target's chain. + g := NewGame() + root := g.tree.Root() + + // Build a 3-ply "e4 c5 Nf3" subtree and a 2-ply "d4 Nc6" sibling + // subtree, both children of root. + buildSubtree := func(sanChain []string) *MoveNode { + parent := root + var last *MoveNode + for _, san := range sanChain { + pos := parent.Position() + if pos == nil { + pos = StartingPosition() + } + child := &MoveNode{move: *mustSAN(pos, san), parent: parent, tree: g.tree} + parent.children = append(parent.children, child) + last = child + parent = child + } + return last + } + + aLeaf := buildSubtree([]string{"e4", "c5", "Nf3"}) + bLeaf := buildSubtree([]string{"d4", "Nc6"}) + + if !g.tree.Goto(aLeaf) { + t.Fatal("Goto(aLeaf) failed") + } + if len(g.tree.undos) != 3 { + t.Fatalf("Goto(aLeaf) undos = %d, want 3", len(g.tree.undos)) + } + + if !g.tree.Goto(bLeaf) { + t.Fatal("Goto(bLeaf) failed") + } + if len(g.tree.undos) != 2 { + t.Fatalf("Goto(bLeaf) undos = %d, want 2 (LCA retreat then forward)", len(g.tree.undos)) + } + if g.tree.Current() != bLeaf { + t.Fatal("Goto(bLeaf) left cursor on wrong node") + } +} + +func TestMoveTreeGotoRejectsForeignTree(t *testing.T) { + g1 := newMoveTreeTestGame() + g2 := newMoveTreeTestGame() + + foreignNode := g2.tree.Current() + before := g1.tree.Current() + + if g1.tree.Goto(foreignNode) { + t.Fatal("Goto with foreign-tree node should return false") + } + if g1.tree.Current() != before { + t.Fatal("Goto(foreign) mutated active cursor") + } +} + +func TestMoveTreeNilSafe(t *testing.T) { + var t1 *MoveTree + if t1.Peek() != nil { + t.Fatal("Peek on nil tree should be nil") + } + if t1.Forward(0) { + t.Fatal("Forward on nil tree should be false") + } + if t1.Goto(nil) { + t.Fatal("Goto on nil tree should be false") + } + t1.Reset() + + g := NewGame() + if g.tree.Goto(nil) { + t.Fatal("Goto(nil) on live tree should be false") + } +} + +func TestMoveNodePositionRestoresOnPanic(t *testing.T) { + // MoveNode.Position's save/restore is a bare `defer setCurrent(current)`; + // defers always run, including on panic, by construction. This test + // pins the broader contract: the cursor returned by Position() is + // observationally pure (the read leaves the tree state unchanged) even + // when the caller panics after the call returns. + g := newMoveTreeTestGame() + before := g.tree.Current() + leaf := g.tree.Current() + + func() { + defer func() { + recover() + if g.tree.Current() != before { + t.Fatal("cursor moved after MoveNode.Position() returned") + } + }() + _ = leaf.Position() + panic("boom") + }() +} + +func TestAddVariationErrorRestoresCursor(t *testing.T) { + g := newMoveTreeTestGame() + root := g.tree.Root() + root.children = nil + before := g.tree.Current() + bogusMove := Move{s1: A1, s2: H8, promo: NoPieceType} + + if _, err := g.tree.AddVariation(root, bogusMove); err == nil { + t.Fatal("AddVariation should error on invalid move") + } + if g.tree.Current() != before { + t.Fatal("AddVariation error left cursor moved") + } +} + +func TestParseVariationErrorRestoresCursor(t *testing.T) { + // Drives parseVariation directly via NewParser (exported via + // export_test.go). Token sequence: open variation, parse a legal move + // that advances the cursor into the abandoned subtree, then trigger + // AddNAG on an invalid NAG value. Pre-fix, parseVariation's err return + // left the cursor on the abandoned subtree node. Post-fix, the defer + // restores oldCurrent. + parser := NewParser([]Token{ + {Type: VariationStart, Value: "("}, + {Type: SQUARE, Value: "e4"}, + {Type: NAG, Value: "!!!"}, // not in nagSymbolToNumeric and not "$N" — ParseNAG errors + {Type: VariationEnd, Value: ")"}, + }) + + before := parser.game.tree.Current() + if err := parser.parseVariation(1, 1); err == nil { + t.Fatal("expected parse error from invalid NAG") + } + after := parser.game.tree.Current() + + if before == nil || after == nil { + t.Fatal("nil cursor before/after parseVariation") + } + if after != before { + t.Fatalf("cursor moved: before=%p after=%p (after parent=%p)", + before, after, after.parent) + } + if isInsideAbandonedVariation(parser.game.tree) { + t.Fatal("cursor stranded inside abandoned variation subtree") + } +} + +// isInsideAbandonedVariation reports whether the tree's active cursor sits +// inside a non-mainline subtree (i.e. it is not reachable from the root +// via children[0] only). +func isInsideAbandonedVariation(t *MoveTree) bool { + if t == nil || t.Root() == nil || t.current == nil { + return false + } + if t.current == t.Root() { + return false + } + node := t.current + for node != nil && node != t.Root() { + parent := node.parent + if parent == nil { + return false + } + idx := -1 + for i, c := range parent.children { + if c == node { + idx = i + break + } + } + if idx > 0 { + return true + } + node = parent + } + return false +} + +func TestMoveTreePeekAcrossReads(t *testing.T) { + // Pinned by TestMoveTreePeekIsLive (same pointer across no-nav reads); + // kept as a smoke test for the zero-state game. + g := NewGame() + if g.tree.Peek() != g.tree.Peek() { + t.Fatal("Peek returned different pointers across two reads with no nav") + } +} diff --git a/nag.go b/nag.go new file mode 100644 index 00000000..521ac95a --- /dev/null +++ b/nag.go @@ -0,0 +1,56 @@ +package chess + +import ( + "errors" + "fmt" +) + +// nagSymbolToNumeric maps the six move-quality symbolic spellings to their +// canonical numeric NAG codes. These are the only symbolic forms accepted on +// import; the canonical, stored, and written form is always the numeric "$N". +var nagSymbolToNumeric = map[string]string{ + "!": "$1", + "?": "$2", + "!!": "$3", + "??": "$4", + "!?": "$5", + "?!": "$6", +} + +// ParseNAG normalises a NAG spelling to its canonical numeric "$N" form. +// +// It accepts: +// - any numeric NAG written as "$" followed by one or more digits (the six +// standard codes as well as ChessBase-style extended codes such as "$1406"), +// - the six move-quality symbolic spellings (! ? !! ?? !? ?!), which are +// mapped to their canonical numeric codes. +// +// Leading zeros in a numeric NAG are stripped ("$01" becomes "$1"). +// +// It rejects malformed input such as "", "$", "$x", "$ 1", "!!!", or any other +// unrecognised spelling. +// +// ParseNAG always returns the canonical numeric "$N" form, never a symbol. +func ParseNAG(s string) (string, error) { + if s == "" { + return "", errors.New("chess: empty NAG") + } + if v, ok := nagSymbolToNumeric[s]; ok { + return v, nil + } + if s[0] != '$' { + return "", fmt.Errorf("chess: invalid NAG %q", s) + } + digits := s[1:] + if digits == "" { + return "", fmt.Errorf("chess: invalid NAG %q: missing digits", s) + } + n := 0 + for _, r := range digits { + if r < '0' || r > '9' { + return "", fmt.Errorf("chess: invalid NAG %q", s) + } + n = n*10 + int(r-'0') + } + return fmt.Sprintf("$%d", n), nil +} diff --git a/nag_test.go b/nag_test.go new file mode 100644 index 00000000..e5a4e2e6 --- /dev/null +++ b/nag_test.go @@ -0,0 +1,49 @@ +package chess + +import "testing" + +func TestParseNAG(t *testing.T) { + tests := []struct { + name string + input string + want string + wantErr bool + }{ + // Symbolic spellings → canonical numeric. + {"bang", "!", "$1", false}, + {"qmark", "?", "$2", false}, + {"double_bang", "!!", "$3", false}, + {"double_qmark", "??", "$4", false}, + {"bang_qmark", "!?", "$5", false}, + {"qmark_bang", "?!", "$6", false}, + + // Numeric forms, including extended ChessBase codes. + {"numeric_one", "$1", "$1", false}, + {"numeric_zero", "$0", "$0", false}, + {"leading_zeros", "$01", "$1", false}, + {"extended", "$1406", "$1406", false}, + {"double_digit", "$13", "$13", false}, + + // Malformed inputs are rejected. + {"empty", "", "", true}, + {"bare_dollar", "$", "", true}, + {"dollar_letter", "$x", "", true}, + {"dollar_space_digit", "$ 1", "", true}, + {"triple_bang", "!!!", "", true}, + {"unknown_symbol", "@", "", true}, + {"letter", "N", "", true}, + {"dollar_minus", "$-1", "", true}, + {"dollar_plus", "$+1", "", true}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + got, err := ParseNAG(tt.input) + if (err != nil) != tt.wantErr { + t.Fatalf("ParseNAG(%q) error = %v, wantErr %v", tt.input, err, tt.wantErr) + } + if !tt.wantErr && got != tt.want { + t.Errorf("ParseNAG(%q) = %q, want %q", tt.input, got, tt.want) + } + }) + } +} diff --git a/notation.go b/notation.go index c6ed5ba7..982bcec2 100644 --- a/notation.go +++ b/notation.go @@ -1,3 +1,10 @@ +// Internal move-text notation for the MoveTextCodec (see ADR-013). +// +// The notation types here (algebraicNotation, longAlgebraicNotation, +// uciNotation) are dispatch targets for MoveTextCodec, not a public surface. +// SAN parse and resolution live in notation_resolver.go, and the public codec +// API is in move_text_codec.go. + package chess import ( @@ -29,26 +36,23 @@ var emptyComponents = moveComponents{} //nolint:gochecknoglobals // false positive. var pgnRegex = regexp.MustCompile(`^(?:([RNBQKP]?)([abcdefgh]?)(\d?)(x?)([abcdefgh])(\d)(=[QRBN])?|(O-O(?:-O)?))([+#!?]|e\.p\.)*$`) -const piecesPoolCapacity = 4 - // Use string pools for common strings to reduce allocations. var ( //nolint:gochecknoglobals // false positive stringPool = sync.Pool{ - New: func() interface{} { + New: func() any { return new(strings.Builder) }, } +) - // Pre-allocate slices for options to avoid allocations in hot path - //nolint:gochecknoglobals // false positive - pieceOptionsPool = sync.Pool{ - New: func() interface{} { - s := make([]string, 0, piecesPoolCapacity) - return &s // Return pointer to slice - }, +func getStringBuilder() *strings.Builder { + sb, ok := stringPool.Get().(*strings.Builder) + if !ok || sb == nil { + return new(strings.Builder) } -) + return sb +} // Constants for common strings to avoid allocations. const ( @@ -65,61 +69,77 @@ const ( captureStr = "x" ) -// Pre-allocate piece type maps for faster lookups. -var pieceTypeToChar = map[PieceType]string{ - King: kingStr, - Queen: queenStr, - Rook: rookStr, - Bishop: bishopStr, - Knight: knightStr, -} - -// Encoder is the interface implemented by objects that can -// encode a move into a string given the position. It is not -// the encoders responsibility to validate the move. -type Encoder interface { - Encode(pos *Position, m *Move) string -} +// Pre-allocate piece type lookup tables for faster hot-path encoding. +var ( + pieceTypeToChar = [7]string{ + King: kingStr, + Queen: queenStr, + Rook: rookStr, + Bishop: bishopStr, + Knight: knightStr, + Pawn: "", + NoPieceType: "", + } -// Decoder is the interface implemented by objects that can -// decode a string into a move given the position. It is not -// the decoders responsibility to validate the move. An error -// is returned if the string could not be decoded. -type Decoder interface { - Decode(pos *Position, s string) (*Move, error) -} + uciPromoToPieceType = [256]PieceType{ + 'n': Knight, + 'b': Bishop, + 'r': Rook, + 'q': Queen, + } +) -// Notation is the interface implemented by objects that can -// encode and decode moves. -type Notation interface { - Encoder - Decoder +func pieceTypeChar(p PieceType) string { + if p < NoPieceType || int(p) >= len(pieceTypeToChar) { + return "" + } + return pieceTypeToChar[p] } -// UCINotation is a more computer friendly alternative to algebraic +// uciNotation is a more computer friendly alternative to algebraic // notation. This notation uses the same format as the UCI (Universal Chess // Interface). Examples: e2e4, e7e5, e1g1 (white short castling), e7e8q (for promotion). -type UCINotation struct{} +type uciNotation struct{} // String implements the fmt.Stringer interface and returns // the notation's name. -func (UCINotation) String() string { - return "UCI Notation" +func (uciNotation) String() string { + return "UCI notation" } -// Encode implements the Encoder interface. -func (UCINotation) Encode(_ *Position, m *Move) string { +// Encode implements the encoder interface. +func (uciNotation) Encode(pos *Position, m Move) string { const maxLen = 5 + // Null move: encode as "0000" (UCI convention). + if m.HasTag(Null) { + return "0000" + } // Get a string builder from the pool - sb, _ := stringPool.Get().(*strings.Builder) + sb := getStringBuilder() sb.Reset() defer stringPool.Put(sb) // Exact size needed: 4 chars for squares + up to 1 for promotion sb.Grow(maxLen) - sb.Write(m.S1().Bytes()) - sb.Write(m.S2().Bytes()) + s1Bytes := m.S1().Bytes() + sb.WriteByte(s1Bytes[0]) + sb.WriteByte(s1Bytes[1]) + + // Chess960 castling uses the king-to-rook form (e.g. "e1h1") per the + // UCI_Chess960 convention, not the standard king-to-destination form + // ("e1g1"). The rook origin is the nearest friendly rook on the king's + // back rank, derived from the board. Without a position the move falls + // back to the king's destination square, matching the standard encoding. + to := m.S2() + if pos != nil && pos.variant == Chess960 && m.HasTag(KingSideCastle|QueenSideCastle) { + if rookFrom, _ := castleRookMove(&pos.board, m, castleKingColor(m.S1())); rookFrom != NoSquare { + to = rookFrom + } + } + toBytes := to.Bytes() + sb.WriteByte(toBytes[0]) + sb.WriteByte(toBytes[1]) if m.Promo() != NoPieceType { sb.Write(m.Promo().Bytes()) } @@ -127,23 +147,30 @@ func (UCINotation) Encode(_ *Position, m *Move) string { return sb.String() } -// Decode implements the Decoder interface. -func (UCINotation) Decode(pos *Position, s string) (*Move, error) { +// Decode implements the decoder interface. +func (uciNotation) Decode(pos *Position, s string) (Move, error) { + // Null move: "0000" is the UCI convention. + if s == "0000" { + return NewNullMove(), nil + } + const promoLen = 5 l := len(s) if l < 4 || l > 5 { - return nil, fmt.Errorf("chess: invalid UCI notation length %d in %q", l, s) + return Move{}, fmt.Errorf("chess: invalid UCI notation length %d in %q", l, s) } - for idx := 0; idx < 2; idx += 2 { - if s[idx+0] < 'a' || s[idx+0] > 'h' { - return nil, fmt.Errorf("chess: invalid UCI notation sq:%v file:%v", - idx/2, s[0]) - } - if s[idx+1] < '1' || s[idx+1] > '8' { - return nil, fmt.Errorf("chess: invalid UCI notation sq:%v rank:%v", - idx/2, s[0]) - } + if s[0] < 'a' || s[0] > 'h' { + return Move{}, fmt.Errorf("chess: invalid UCI notation sq:0 file:%c", s[0]) + } + if s[1] < '1' || s[1] > '8' { + return Move{}, fmt.Errorf("chess: invalid UCI notation sq:0 rank:%c", s[1]) + } + if s[2] < 'a' || s[2] > 'h' { + return Move{}, fmt.Errorf("chess: invalid UCI notation sq:1 file:%c", s[2]) + } + if s[3] < '1' || s[3] > '8' { + return Move{}, fmt.Errorf("chess: invalid UCI notation sq:1 rank:%c", s[3]) } // Convert directly instead of using map lookups @@ -151,47 +178,102 @@ func (UCINotation) Decode(pos *Position, s string) (*Move, error) { s2 := Square((s[2] - 'a') + (s[3]-'1')*8) if s1 < A1 || s1 > H8 || s2 < A1 || s2 > H8 { - return nil, fmt.Errorf("chess: invalid squares in UCI notation %q", s) + return Move{}, fmt.Errorf("chess: invalid squares in UCI notation %q", s) } m := Move{s1: s1, s2: s2} // Promotion (Use a precomputed lookup) if l == promoLen { - promoMap := [256]PieceType{ - 'n': Knight, 'b': Bishop, 'r': Rook, 'q': Queen, - } - promo := promoMap[s[4]] + promo := uciPromoToPieceType[s[4]] if promo == NoPieceType { - return nil, fmt.Errorf("chess: invalid promotion piece in UCI notation %q", s) + return Move{}, fmt.Errorf("chess: invalid promotion piece in UCI notation %q", s) } m.promo = promo } + // Chess960 castling may arrive in the king-to-rook form ("e1h1") from + // engines using the UCI_Chess960 option. Resolve it to the canonical + // castle, whose destination is the standard king square (g1/c1). Plain + // moves and the standard king-to-destination form fall through unchanged. + if castle, ok := chess960UCICastleMove(pos, m); ok { + return castle, nil + } + if pos == nil { - return &m, nil + return m, nil } - m.tags = moveTags(m, pos) + tag, _ := newLegality(pos, generateLegalAnnotated).legal(m) + m.tags = tag - m.position = pos.Update(&m) + return m, nil +} - return &m, nil +// castleKingColor returns the color of a king making a castle from kingFrom. +// Legal castles always originate on rank 1 for White or rank 8 for Black. +func castleKingColor(kingFrom Square) Color { + if kingFrom.Rank() == Rank1 { + return White + } + return Black } -// AlgebraicNotation (or Standard Algebraic Notation) is the +// chess960UCICastleMove resolves a Chess960 king-to-rook castling candidate +// such as "e1h1" to its canonical Move. The returned Move carries the castle +// tag and the standard king destination (g1/c1). A promotion, non-Chess960 +// position, king capture, or plain step never matches a castle. The second +// result is false when no legal castle matches. +func chess960UCICastleMove(pos *Position, candidate Move) (Move, bool) { + if pos == nil || pos.variant != Chess960 || candidate.promo != NoPieceType { + return Move{}, false + } + kingFrom := candidate.s1 + rookFrom := candidate.s2 + + var found Move + match := false + visitLegalMoves(pos, generateLegalAnnotated, func(m Move) bool { + if !m.HasTag(KingSideCastle) && !m.HasTag(QueenSideCastle) { + return false + } + if m.s1 != kingFrom { + return false + } + rf, _ := castleRookMove(&pos.board, m, castleKingColor(kingFrom)) + if rf != rookFrom { + return false + } + if m.HasTag(KingSideCastle) && rookFrom.File() <= kingFrom.File() { + return false + } + if m.HasTag(QueenSideCastle) && rookFrom.File() >= kingFrom.File() { + return false + } + found = m + match = true + return true + }) + return found, match +} + +// algebraicNotation (or Standard Algebraic notation) is the // official chess notation used by FIDE. Examples: e4, e5, // O-O (short castling), e8=Q (promotion). -type AlgebraicNotation struct{} +type algebraicNotation struct{} // String implements the fmt.Stringer interface and returns // the notation's name. -func (AlgebraicNotation) String() string { - return "Algebraic Notation" +func (algebraicNotation) String() string { + return "Algebraic notation" } -// Encode implements the Encoder interface. -func (AlgebraicNotation) Encode(pos *Position, m *Move) string { +// Encode implements the encoder interface. +func (algebraicNotation) Encode(pos *Position, m Move) string { + // Null move: emit "Z0" (ChessBase / Scid convention). + if m.HasTag(Null) { + return "Z0" + } // Handle castling without builder checkChar := getCheckChar(pos, m) if m.HasTag(KingSideCastle) { @@ -202,12 +284,12 @@ func (AlgebraicNotation) Encode(pos *Position, m *Move) string { } // Get a string builder from the pool - sb, _ := stringPool.Get().(*strings.Builder) + sb := getStringBuilder() sb.Reset() defer stringPool.Put(sb) p := pos.Board().Piece(m.S1()) - if pChar := pieceTypeToChar[p.Type()]; pChar != "" { + if pChar := pieceTypeChar(p.Type()); pChar != "" { sb.WriteString(pChar) } @@ -226,7 +308,7 @@ func (AlgebraicNotation) Encode(pos *Position, m *Move) string { if m.promo != NoPieceType { sb.WriteString(equalStr) - sb.WriteString(pieceTypeToChar[m.promo]) + sb.WriteString(pieceTypeChar(m.promo)) } sb.WriteString(getCheckChar(pos, m)) @@ -253,145 +335,79 @@ func algebraicNotationParts(s string) (moveComponents, error) { }, nil } -// cleanMove creates a standardized string from move components. -func (mc moveComponents) clean() string { - // Get a string builder from pool - sb, _ := stringPool.Get().(*strings.Builder) - sb.Reset() - defer stringPool.Put(sb) - - sb.WriteString(mc.piece) - sb.WriteString(mc.originFile) - sb.WriteString(mc.originRank) - sb.WriteString(mc.capture) - sb.WriteString(mc.file) - sb.WriteString(mc.rank) - sb.WriteString(mc.promotes) - sb.WriteString(mc.castles) - - return sb.String() -} - -// generateMoveOptions creates possible alternative notations for a move. -func (mc moveComponents) generateOptions() []string { - // Get pre-allocated slice from pool - options := pieceOptionsPool.Get().(*[]string) - *options = (*options)[:0] // Clear but keep capacity - defer pieceOptionsPool.Put(options) // Now passing pointer - - // Build move options using string builder for efficiency - sb, _ := stringPool.Get().(*strings.Builder) - defer stringPool.Put(sb) - - if mc.piece != "" { - // Option 1: no origin coordinates - sb.Reset() - sb.WriteString(mc.piece) - sb.WriteString(mc.capture) - sb.WriteString(mc.file) - sb.WriteString(mc.rank) - sb.WriteString(mc.promotes) - sb.WriteString(mc.castles) - *options = append(*options, sb.String()) - - // Option 2: with rank, no file - sb.Reset() - sb.WriteString(mc.piece) - sb.WriteString(mc.originRank) - sb.WriteString(mc.capture) - sb.WriteString(mc.file) - sb.WriteString(mc.rank) - sb.WriteString(mc.promotes) - sb.WriteString(mc.castles) - *options = append(*options, sb.String()) - - // Option 3: with file, no rank - sb.Reset() - sb.WriteString(mc.piece) - sb.WriteString(mc.originFile) - sb.WriteString(mc.capture) - sb.WriteString(mc.file) - sb.WriteString(mc.rank) - sb.WriteString(mc.promotes) - sb.WriteString(mc.castles) - *options = append(*options, sb.String()) - } else { - if mc.capture != "" { - // Pawn capture without rank - sb.Reset() - sb.WriteString(mc.originFile) - sb.WriteString(mc.capture) - sb.WriteString(mc.file) - sb.WriteString(mc.rank) - sb.WriteString(mc.promotes) - *options = append(*options, sb.String()) - } - if mc.originFile != "" && mc.originRank != "" { - // Full coordinates version - sb.Reset() - sb.WriteString(mc.capture) - sb.WriteString(mc.file) - sb.WriteString(mc.rank) - sb.WriteString(mc.promotes) - *options = append(*options, sb.String()) - } +// decodeSANText parses a SAN string and resolves it to a legal move. +// The canonical flag controls disambiguation strictness: true rejects +// redundant disambiguation (strict SAN), false accepts it (PGN import). +func decodeSANText(pos *Position, s string, canonical bool) (Move, error) { + switch s { + case "Z0", "Z1", "--", "@@": + return NewNullMove(), nil } - return *options -} - -// Decode implements the Decoder interface. -func (AlgebraicNotation) Decode(pos *Position, s string) (*Move, error) { - // Parse move components components, err := algebraicNotationParts(s) if err != nil { - return nil, err + return Move{}, err } - // Get cleaned input move - cleanedInput := components.clean() - - // Try matching against valid moves - for _, m := range pos.ValidMovesUnsafe() { - // Encode current move - moveStr := AlgebraicNotation{}.Encode(pos, &m) - - // Parse and clean encoded move - notationParts, algebraicNotationError := algebraicNotationParts(moveStr) - if algebraicNotationError != nil { - continue // Skip invalid moves - } + dest := NoSquare + if components.file != "" && components.rank != "" { + dest = squareFromFileRank(components.file[0], components.rank[0]) + } - // Compare cleaned versions - if cleanedInput == notationParts.clean() { - return &m, nil - } + return resolveSANMove(pos, sanMoveData{ + castle: components.castles, + piece: algebraicPieceType(components.piece), + originFile: components.originFile, + originRank: components.originRank, + dest: dest, + capture: components.capture != "", + promotion: algebraicPromotion(components.promotes), + canonical: canonical, + }) +} - // Try alternative notations - for _, opt := range components.generateOptions() { - if opt == notationParts.clean() { - return &m, nil - } - } +func algebraicPieceType(piece string) PieceType { + switch piece { + case kingStr: + return King + case queenStr: + return Queen + case rookStr: + return Rook + case bishopStr: + return Bishop + case knightStr: + return Knight + default: + return Pawn } +} - return nil, fmt.Errorf("chess: move %s is not valid", s) +func algebraicPromotion(promotes string) PieceType { + if len(promotes) != 2 || promotes[0] != '=' { + return NoPieceType + } + return algebraicPieceType(promotes[1:]) } -// LongAlgebraicNotation is a fully expanded version of +// longAlgebraicNotation is a fully expanded version of // algebraic notation in which the starting and ending // squares are specified. // Examples: e2e4, Rd3xd7, O-O (short castling), e7e8=Q (promotion). -type LongAlgebraicNotation struct{} +type longAlgebraicNotation struct{} // String implements the fmt.Stringer interface and returns // the notation's name. -func (LongAlgebraicNotation) String() string { - return "Long Algebraic Notation" +func (longAlgebraicNotation) String() string { + return "Long Algebraic notation" } -// Encode implements the Encoder interface. -func (LongAlgebraicNotation) Encode(pos *Position, m *Move) string { +// Encode implements the encoder interface. +func (longAlgebraicNotation) Encode(pos *Position, m Move) string { + // Null move: emit "0000" (UCI / long-algebraic convention). + if m.HasTag(Null) { + return "0000" + } checkChar := getCheckChar(pos, m) if m.HasTag(KingSideCastle) { return "O-O" + checkChar @@ -399,7 +415,7 @@ func (LongAlgebraicNotation) Encode(pos *Position, m *Move) string { return "O-O-O" + checkChar } p := pos.Board().Piece(m.S1()) - pChar := charFromPieceType(p.Type()) + pChar := pieceTypeChar(p.Type()) s1Str := m.s1.String() capChar := "" if m.HasTag(Capture) || m.HasTag(EnPassant) { @@ -412,80 +428,84 @@ func (LongAlgebraicNotation) Encode(pos *Position, m *Move) string { return pChar + s1Str + capChar + m.s2.String() + promoText + checkChar } -// Decode implements the Decoder interface. -func (LongAlgebraicNotation) Decode(pos *Position, s string) (*Move, error) { - return AlgebraicNotation{}.Decode(pos, s) +// Decode implements the decoder interface. +func (longAlgebraicNotation) Decode(pos *Position, s string) (Move, error) { + // "0000" is the UCI / long-algebraic spelling for a null move; the + // algebraic decoder doesn't recognise it. + if s == "0000" { + return NewNullMove(), nil + } + return decodeSANText(pos, s, true) } -func getCheckChar(pos *Position, move *Move) string { +func getCheckChar(pos *Position, move Move) string { if !move.HasTag(Check) { return "" } nextPos := pos.Update(move) if nextPos.Status() == Checkmate { - return "#" + return mateStr } - return "+" + return checkStr } -func formS1(pos *Position, m *Move) string { +func formS1(pos *Position, m Move) string { p := pos.board.Piece(m.s1) if p.Type() == Pawn { return "" } - var req, fileReq, rankReq bool + var ( + disambiguationNeeded bool + otherOnSameFile bool + otherOnSameRank bool + ) // Use a string builder from the pool - sb, _ := stringPool.Get().(*strings.Builder) + sb := getStringBuilder() sb.Reset() defer stringPool.Put(sb) for _, mv := range pos.ValidMovesUnsafe() { - if mv.s1 != m.s1 && mv.s2 == m.s2 && p == pos.board.Piece(mv.s1) { - req = true - - if mv.s1.File() == m.s1.File() { - rankReq = true - } - - if mv.s1.Rank() == m.s1.Rank() { - fileReq = true - } + if mv.s1 == m.s1 || mv.s2 != m.s2 { + continue + } + if p != pos.board.Piece(mv.s1) { + continue + } + disambiguationNeeded = true + if mv.s1.File() == m.s1.File() { + otherOnSameFile = true + } + if mv.s1.Rank() == m.s1.Rank() { + otherOnSameRank = true } } - if fileReq || !rankReq && req { + // SAN disambiguation rules (FIDE): + // * If no other same-type piece can move to s2, no disambiguation needed. + // * If file alone disambiguates, emit the file. + // * Otherwise (file shared with another same-target piece), emit the rank. + // * If three or more pieces share the same file, emit both. + if !disambiguationNeeded { + return "" + } + if !otherOnSameFile { sb.WriteByte(m.s1.File().Byte()) + return sb.String() } - - if rankReq { - sb.WriteByte(m.s1.Rank().Byte()) + if otherOnSameRank { + // Three or more same-file pieces: emit both file and rank. + sb.WriteByte(m.s1.File().Byte()) } - + sb.WriteByte(m.s1.Rank().Byte()) return sb.String() } func charForPromo(p PieceType) string { - c := charFromPieceType(p) + c := pieceTypeChar(p) if c != "" { c = "=" + c } return c } - -func charFromPieceType(p PieceType) string { - switch p { - case King: - return "K" - case Queen: - return "Q" - case Rook: - return "R" - case Bishop: - return "B" - case Knight: - return "N" - } - return "" -} diff --git a/notation_resolver.go b/notation_resolver.go new file mode 100644 index 00000000..8f963c7b --- /dev/null +++ b/notation_resolver.go @@ -0,0 +1,266 @@ +// SAN resolver: parses and resolves Standard Algebraic Notation move text. +// +// Codec-internal companion to notation.go. The MoveTextCodec (see +// move_text_codec.go, ADR-013) is the public surface; this file holds the SAN +// parse and resolution used by the SAN and PGN-import notation types. + +package chess + +import ( + "errors" + "fmt" + "strings" +) + +type sanMoveData struct { + castle string + piece PieceType + originFile string + originRank string + dest Square + capture bool + promotion PieceType + canonical bool +} + +func resolveSANMove(pos *Position, data sanMoveData) (Move, error) { + if data.castle != "" { + return resolveSANCastle(pos, data.castle) + } + if data.dest == NoSquare { + return Move{}, errorsInvalidSANMove() + } + + if matched, ok := resolveSANMoveDirect(pos, data); ok { + return matched, nil + } + + var mismatchReasons []string + originFile := byte(0) + if data.originFile != "" { + originFile = data.originFile[0] + } + originRank := int8(-1) + if data.originRank != "" { + originRank = int8(data.originRank[0] - '1') + } + + var matched Move + matchedMove := false + visitLegalMoves(pos, generateLegalAnnotated, func(m Move) bool { + if m.S2() != data.dest { + return false + } + + piece := pos.board.Piece(m.S1()) + if piece.Type() != data.piece { + mismatchReasons = append(mismatchReasons, "piece type mismatch") + return false + } + if originFile != 0 && m.S1().File().Byte() != originFile { + mismatchReasons = append(mismatchReasons, "origin file mismatch") + return false + } + if originRank >= 0 && int8(m.S1().Rank()) != originRank { + mismatchReasons = append(mismatchReasons, fmt.Sprintf("origin rank mismatch: %d", m.S1()/8+1)) + return false + } + if data.canonical && data.piece != Pawn && data.originFile+data.originRank != formS1(pos, m) { + mismatchReasons = append(mismatchReasons, "disambiguation mismatch") + return false + } + + moveCaptures := m.HasTag(Capture) || m.HasTag(EnPassant) + if data.capture != moveCaptures { + mismatchReasons = append(mismatchReasons, "capture mismatch") + return false + } + if data.promotion != NoPieceType && m.promo != data.promotion { + mismatchReasons = append(mismatchReasons, "promotion mismatch") + return false + } + + matched = m + matchedMove = true + return true + }) + + if matchedMove { + return matched, nil + } + if len(mismatchReasons) > 0 { + return Move{}, fmt.Errorf("chess: no legal move found for position: %s", strings.Join(mismatchReasons, "; ")) + } + return Move{}, errorsInvalidSANMove() +} + +func resolveSANMoveDirect(pos *Position, data sanMoveData) (Move, bool) { + var origins [16]Square + count := sanCandidateOrigins(pos, data, &origins) + if count == 0 { + return Move{}, false + } + + originFile := byte(0) + if data.originFile != "" { + originFile = data.originFile[0] + } + originRank := int8(-1) + if data.originRank != "" { + originRank = int8(data.originRank[0] - '1') + } + + for i := range count { + s1 := origins[i] + if originFile != 0 && s1.File().Byte() != originFile { + continue + } + if originRank >= 0 && int8(s1.Rank()) != originRank { + continue + } + + p := pos.board.Piece(s1) + if p.Type() != data.piece || p.Color() != pos.turn { + continue + } + + m := Move{s1: s1, s2: data.dest, promo: data.promotion} + if data.piece == Pawn && data.promotion == NoPieceType && pawnPromotes(pos.turn, data.dest) { + continue + } + if data.piece != Pawn && data.promotion != NoPieceType { + continue + } + + tags, ok := newLegality(pos, generateLegalAnnotated).legal(m) + if !ok { + continue + } + m.tags = tags + + moveCaptures := m.HasTag(Capture) || m.HasTag(EnPassant) + if data.capture != moveCaptures { + continue + } + if data.canonical && data.piece != Pawn && data.originFile+data.originRank != formS1(pos, m) { + continue + } + + return m, true + } + return Move{}, false +} + +func sanCandidateOrigins(pos *Position, data sanMoveData, origins *[16]Square) int { + switch data.piece { + case Pawn: + return sanPawnCandidateOrigins(pos, data, origins) + case Knight: + return sanOriginsFromBitboard(pos.board.bbForPiece(NewPiece(Knight, pos.turn))&bbKnightMoves[data.dest], origins) + case Bishop: + occ := ^pos.board.emptySqs + return sanOriginsFromBitboard(pos.board.bbForPiece(NewPiece(Bishop, pos.turn))&diaAttack(occ, data.dest), origins) + case Rook: + occ := ^pos.board.emptySqs + return sanOriginsFromBitboard(pos.board.bbForPiece(NewPiece(Rook, pos.turn))&hvAttack(occ, data.dest), origins) + case Queen: + occ := ^pos.board.emptySqs + return sanOriginsFromBitboard(pos.board.bbForPiece(NewPiece(Queen, pos.turn))&(diaAttack(occ, data.dest)|hvAttack(occ, data.dest)), origins) + case King: + return sanOriginsFromBitboard(pos.board.bbForPiece(NewPiece(King, pos.turn))&bbKingMoves[data.dest], origins) + default: + return 0 + } +} + +func sanOriginsFromBitboard(bb bitboard, origins *[16]Square) int { + count := 0 + for bits := bb; bits != 0; bits &= bits - 1 { + origins[count] = squareFromBit(bits & -bits) + count++ + } + return count +} + +func sanPawnCandidateOrigins(pos *Position, data sanMoveData, origins *[16]Square) int { + count := 0 + dest := data.dest + pawns := pos.board.bbForPiece(NewPiece(Pawn, pos.turn)) + add := func(sq Square) { + if sq < A1 || sq > H8 { + return + } + if pawns&bbForSquare(sq) == 0 { + return + } + origins[count] = sq + count++ + } + + if pos.turn == White { + if data.capture { + if dest.File() != FileA { + add(dest - 9) + } + if dest.File() != FileH { + add(dest - 7) + } + return count + } + if dest.Rank() > Rank1 { + one := dest - 8 + add(one) + if dest.Rank() == Rank4 && !pos.board.isOccupied(one) { + add(dest - 16) + } + } + return count + } + + if data.capture { + if dest.File() != FileA { + add(dest + 7) + } + if dest.File() != FileH { + add(dest + 9) + } + return count + } + if dest.Rank() < Rank8 { + one := dest + 8 + add(one) + if dest.Rank() == Rank5 && !pos.board.isOccupied(one) { + add(dest + 16) + } + } + return count +} + +func pawnPromotes(turn Color, dest Square) bool { + return (turn == White && dest.Rank() == Rank8) || (turn == Black && dest.Rank() == Rank1) +} + +func resolveSANCastle(pos *Position, castle string) (Move, error) { + var castles [2]Move + count := castleMovesInto(pos, &castles, generateLegalAnnotated) + for _, m := range castles[:count] { + if castle == castleKS && m.HasTag(KingSideCastle) { + return m, nil + } + if castle == castleQS && m.HasTag(QueenSideCastle) { + return m, nil + } + } + return Move{}, errorsInvalidSANMove() +} + +func errorsInvalidSANMove() error { + return errors.New("chess: no legal move found for position") +} + +func squareFromFileRank(file, rank byte) Square { + if file < 'a' || file > 'h' || rank < '1' || rank > '8' { + return NoSquare + } + return Square((file - 'a') + (rank-'1')*8) +} diff --git a/notation_test.go b/notation_test.go index bb0bb97a..29729848 100644 --- a/notation_test.go +++ b/notation_test.go @@ -1,108 +1,281 @@ package chess import ( - "fmt" "strings" "testing" ) -type notationDecodeTest struct { - N Notation - Pos *Position - Text string - PostPos *Position +type decodeTest struct { + Codec MoveTextCodec + Pos *Position + Text string } -var invalidDecodeTests = []notationDecodeTest{ +var invalidDecodeTests = []decodeTest{ { // opening for white - N: AlgebraicNotation{}, - Pos: unsafeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"), - Text: "e5", + Codec: SAN(), + Pos: unsafeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"), + Text: "e5", }, { // http://en.lichess.org/W91M4jms#14 - N: AlgebraicNotation{}, - Pos: unsafeFEN("rn1qkb1r/pp3ppp/2p1pn2/3p4/2PP4/2NQPN2/PP3PPP/R1B1K2R b KQkq - 0 7"), - Text: "Nd7", + Codec: SAN(), + Pos: unsafeFEN("rn1qkb1r/pp3ppp/2p1pn2/3p4/2PP4/2NQPN2/PP3PPP/R1B1K2R b KQkq - 0 7"), + Text: "Nd7", }, { // http://en.lichess.org/W91M4jms#17 - N: AlgebraicNotation{}, - Pos: unsafeFEN("r2qk2r/pp1n1ppp/2pbpn2/3p4/2PP4/1PNQPN2/P4PPP/R1B1K2R w KQkq - 1 9"), - Text: "O-O-O-O", - PostPos: unsafeFEN("r2qk2r/pp1n1ppp/2pbpn2/3p4/2PP4/1PNQPN2/P4PPP/R1B2RK1 b kq - 2 9"), + Codec: SAN(), + Pos: unsafeFEN("r2qk2r/pp1n1ppp/2pbpn2/3p4/2PP4/1PNQPN2/P4PPP/R1B1K2R w KQkq - 1 9"), + Text: "O-O-O-O", }, { // http://en.lichess.org/W91M4jms#23 - N: AlgebraicNotation{}, - Pos: unsafeFEN("3r1rk1/pp1nqppp/2pbpn2/3p4/2PP4/1PNQPN2/PB3PPP/3RR1K1 b - - 5 12"), - Text: "dx4", + Codec: SAN(), + Pos: unsafeFEN("3r1rk1/pp1nqppp/2pbpn2/3p4/2PP4/1PNQPN2/PB3PPP/3RR1K1 b - - 5 12"), + Text: "dx4", }, { // should not assume pawn for unknown piece type "n" - N: AlgebraicNotation{}, - Pos: unsafeFEN("rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2"), - Text: "nf3", + Codec: SAN(), + Pos: unsafeFEN("rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2"), + Text: "nf3", }, { // disambiguation should not allow for this since it is not a capture - N: AlgebraicNotation{}, - Pos: unsafeFEN("rnbqkbnr/ppp1pppp/8/3p4/3P4/8/PPP1PPPP/RNBQKBNR w KQkq - 0 2"), - Text: "bf4", + Codec: SAN(), + Pos: unsafeFEN("rnbqkbnr/ppp1pppp/8/3p4/3P4/8/PPP1PPPP/RNBQKBNR w KQkq - 0 2"), + Text: "bf4", }, } func TestInvalidDecoding(t *testing.T) { for _, test := range invalidDecodeTests { - if _, err := test.N.Decode(test.Pos, test.Text); err == nil { + if _, err := test.Codec.Decode(test.Pos, test.Text); err == nil { t.Fatalf("starting from board\n%s\n expected move notation %s to be invalid", test.Pos.board.Draw(), test.Text) } } } +func TestAlgebraicDisambiguation(t *testing.T) { + tests := []struct { + name string + fen string + move Move + want string + }{ + { + // Two white rooks, one on a2 and one on d5, both can move to a5 + // (same destination, different file and rank). Standard SAN + // requires only the file: Raa5 and Rda5. + name: "file disambiguation, no shared file or rank", + fen: "1k6/8/8/3R4/8/8/R7/K7 w - - 0 1", + move: Move{s1: A2, s2: A5}, + want: "Raa5", + }, + { + // Same position, the other rook: should encode Rda5. + name: "file disambiguation, no shared file or rank, other rook", + fen: "1k6/8/8/3R4/8/8/R7/K7 w - - 0 1", + move: Move{s1: D5, s2: A5}, + want: "Rda5", + }, + } + codec := SAN() + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + pos := unsafeFEN(tt.fen) + got, err := codec.Encode(pos, tt.move) + if err != nil { + t.Fatalf("Encode() error = %v", err) + } + if got != tt.want { + t.Fatalf("Encode = %q, want %q", got, tt.want) + } + }) + } +} + +func TestAlgebraicNotationDecodeRoundTripsLegalMoves(t *testing.T) { + positions := []*Position{ + startPos, + midPos, + complexPos, + unsafeFEN("r3k2r/pppq1ppp/2npbn2/3Np3/2B1P3/2N2Q2/PPP2PPP/R3K2R w KQkq - 0 10"), + } + codec := SAN() + + for _, pos := range positions { + for _, move := range pos.ValidMovesUnsafe() { + encoded, err := codec.Encode(pos, move) + if err != nil { + t.Fatalf("Encode(%s) from %s: %v", move, pos, err) + } + decoded, err := codec.Decode(pos, encoded) + if err != nil { + t.Fatalf("Decode(%q) from %s: %v", encoded, pos, err) + } + if decoded.s1 != move.s1 || decoded.s2 != move.s2 || decoded.promo != move.promo { + t.Fatalf("Decode(%q) = %s, want %s", encoded, decoded, move) + } + } + } +} + func TestEncodeUCINotation(t *testing.T) { - notation := UCINotation{} + codec := UCI() pos := unsafeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1") - move := &Move{s1: E2, s2: E4} + move := Move{s1: E2, s2: E4} expected := "e2e4" - result := notation.Encode(pos, move) + result, err := codec.Encode(pos, move) + if err != nil { + t.Fatalf("Encode() error = %v", err) + } if result != expected { t.Fatalf("expected %s, got %s", expected, result) } } func TestEncodeUCINotationWithPromotion(t *testing.T) { - notation := UCINotation{} + codec := UCI() pos := unsafeFEN("8/P7/8/8/8/8/8/8 w - - 0 1") - move := &Move{s1: A7, s2: A8, promo: Queen} + move := Move{s1: A7, s2: A8, promo: Queen} expected := "a7a8q" - result := notation.Encode(pos, move) + result, err := codec.Encode(pos, move) + if err != nil { + t.Fatalf("Encode() error = %v", err) + } if result != expected { t.Fatalf("expected %s, got %s", expected, result) } } func TestEncodeUCINotationWithInvalidMove(t *testing.T) { - notation := UCINotation{} + codec := UCI() pos := unsafeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1") - move := &Move{s1: E2, s2: E5} + move := Move{s1: E2, s2: E5} expected := "e2e5" - result := notation.Encode(pos, move) + result, err := codec.Encode(pos, move) + if err != nil { + t.Fatalf("Encode() error = %v", err) + } if result != expected { t.Fatalf("expected %s, got %s", expected, result) } } +func TestNotationHandlesInvalidPooledStringBuilder(t *testing.T) { + tests := []struct { + name string + run func() string + want string + }{ + { + name: "uci encode", + run: func() string { + s, err := UCI().Encode(nil, Move{s1: E2, s2: E4}) + if err != nil { + t.Fatalf("UCI().Encode() error = %v", err) + } + return s + }, + want: "e2e4", + }, + { + name: "algebraic encode", + run: func() string { + pos := unsafeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1") + s, err := SAN().Encode(pos, Move{s1: E2, s2: E4}) + if err != nil { + t.Fatalf("SAN().Encode() error = %v", err) + } + return s + }, + want: "e4", + }, + { + name: "form source square", + run: func() string { + pos := unsafeFEN("1k6/8/8/3R4/8/8/R7/K7 w - - 0 1") + return formS1(pos, Move{s1: A2, s2: A5}) + }, + want: "a", + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + stringPool.Put("not a string builder") + if got := tt.run(); got != tt.want { + t.Fatalf("got %q, want %q", got, tt.want) + } + }) + } +} + +func TestUCINotationGrammar(t *testing.T) { + tests := []struct { + name string + input string + wantErr bool + }{ + { + name: "invalid UCI notation length", + input: "e2e", + wantErr: true, + }, + { + name: "invalid squares in UCI notation", + input: "e9e4", + wantErr: true, + }, + { + name: "invalid promotion piece", + input: "a7a8x", + wantErr: true, + }, + { + name: "invalid source file character", + input: "i1e4", + wantErr: true, + }, + { + name: "invalid destination file character", + input: "e1i4", + wantErr: true, + }, + { + name: "invalid destination rank character", + input: "e1e0", + wantErr: true, + }, + { + name: "invalid source rank character", + input: "e0e4", + wantErr: true, + }, + } + + codec := UCI() + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + err := codec.ValidateSyntax(tt.input) + if (err != nil) != tt.wantErr { + t.Fatalf("ValidateSyntax() error = %v, wantErr %v", err, tt.wantErr) + } + }) + } +} + func TestUCINotationDecode(t *testing.T) { - moveWithCheckCapture := &Move{s1: D1, s2: D8, tags: Check} - moveWithCheckCapture.AddTag(Capture) + moveWithCheckCapture := Move{s1: D1, s2: D8, tags: Check}.WithTag(Capture) tests := []struct { name string pos *Position input string - want *Move + want Move wantErr bool expectedPos *Position }{ @@ -110,7 +283,7 @@ func TestUCINotationDecode(t *testing.T) { name: "valid move without promotion", pos: unsafeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"), input: "e2e4", - want: &Move{s1: E2, s2: E4}, + want: Move{s1: E2, s2: E4}, expectedPos: unsafeFEN("rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1"), wantErr: false, }, @@ -118,7 +291,7 @@ func TestUCINotationDecode(t *testing.T) { name: "valid move with promotion", pos: unsafeFEN("8/P7/8/8/8/8/8/8 w - - 0 1"), input: "a7a8q", - want: &Move{s1: A7, s2: A8, promo: Queen}, + want: Move{s1: A7, s2: A8, promo: Queen}, expectedPos: unsafeFEN("Q7/8/8/8/8/8/8/8 b - - 0 1"), wantErr: false, }, @@ -126,7 +299,7 @@ func TestUCINotationDecode(t *testing.T) { name: "valid move with capture", pos: unsafeFEN("rnbqkb1r/ppp2ppp/3p1n2/4P3/4P3/2N5/PPP2PPP/R1BQKBNR b KQkq - 0 4"), input: "d6e5", - want: &Move{s1: D6, s2: E5, tags: Capture}, + want: Move{s1: D6, s2: E5, tags: Capture}, wantErr: false, expectedPos: unsafeFEN("rnbqkb1r/ppp2ppp/5n2/4p3/4P3/2N5/PPP2PPP/R1BQKBNR w KQkq - 0 5"), }, @@ -134,7 +307,7 @@ func TestUCINotationDecode(t *testing.T) { name: "valid move with check only", pos: unsafeFEN("rnbqkb1r/ppp2ppp/5n2/4p3/4P3/2N5/PPP2PPP/R1BQKBNR w KQkq - 0 5"), input: "f1b5", - want: &Move{s1: F1, s2: B5, tags: Check}, + want: Move{s1: F1, s2: B5, tags: Check}, expectedPos: unsafeFEN("rnbqkb1r/ppp2ppp/5n2/1B2p3/4P3/2N5/PPP2PPP/R1BQK1NR b KQkq - 1 5"), wantErr: false, }, @@ -150,7 +323,7 @@ func TestUCINotationDecode(t *testing.T) { name: "valid move with castle with check", pos: unsafeFEN("r4b1r/ppp3pp/8/4p3/2Pq4/3P1Q2/PP3PPP/1k2K2R w K - 2 19"), input: "e1g1", - want: &Move{s1: E1, s2: G1, tags: Check | KingSideCastle}, + want: Move{s1: E1, s2: G1, tags: Check | KingSideCastle}, wantErr: false, expectedPos: unsafeFEN("r4b1r/ppp3pp/8/4p3/2Pq4/3P1Q2/PP3PPP/1k3RK1 b - - 3 19"), }, @@ -158,45 +331,24 @@ func TestUCINotationDecode(t *testing.T) { name: "valid en passant move with check", pos: unsafeFEN("r3k1r1/pbppqpb1/1pn3p1/7p/1N2pPn1/1PP4N/PB1P2PP/2QRK1R1 b q f3 0 2"), input: "e4f3", - want: &Move{s1: E4, s2: F3, tags: Check | EnPassant}, + want: Move{s1: E4, s2: F3, tags: Check | EnPassant}, wantErr: false, expectedPos: unsafeFEN("r3k1r1/pbppqpb1/1pn3p1/7p/1N4n1/1PP2p1N/PB1P2PP/2QRK1R1 w q - 0 3"), }, - { - name: "invalid UCI notation length", - pos: nil, - input: "e2e", - want: nil, - wantErr: true, - }, - { - name: "invalid squares in UCI notation", - pos: nil, - input: "e9e4", - want: nil, - wantErr: true, - }, - { - name: "invalid promotion piece", - pos: nil, - input: "a7a8x", - want: nil, - wantErr: true, - }, { name: "valid en passant move", pos: unsafeFEN("rnbqkbnr/ppp2ppp/4p3/3pP3/8/8/PPPP1PPP/RNBQKBNR w KQkq d6 0 3"), input: "e5d6", - want: &Move{s1: E5, s2: D6, tags: EnPassant}, + want: Move{s1: E5, s2: D6, tags: EnPassant}, wantErr: false, expectedPos: unsafeFEN("rnbqkbnr/ppp2ppp/3Pp3/8/8/8/PPPP1PPP/RNBQKBNR b KQkq - 0 3"), }, } + codec := UCI() for _, tt := range tests { t.Run(tt.name, func(t *testing.T) { - notation := UCINotation{} - got, err := notation.Decode(tt.pos, tt.input) + got, err := codec.Decode(tt.pos, tt.input) if (err != nil) != tt.wantErr { t.Errorf("Decode() error = %v, wantErr %v", err, tt.wantErr) return @@ -204,12 +356,9 @@ func TestUCINotationDecode(t *testing.T) { if !tt.wantErr && (got.String() != tt.want.String() || got.promo != tt.want.promo || got.tags != tt.want.tags) { t.Errorf("Decode() = %v (%d), want %v (%d)", got, got.tags, tt.want, tt.want.tags) } - if !tt.wantErr && tt.want.position != nil && got.position != nil && tt.want.position.String() != got.position.String() { - t.Errorf("Decode() = %v, want %v", got.position, tt.want.position) - } - if !tt.wantErr && tt.expectedPos != nil && got.position.String() != tt.expectedPos.String() { - t.Errorf("Decode() = %v, want %v", got.position.String(), tt.expectedPos) + if !tt.wantErr && tt.expectedPos != nil && tt.pos.Update(got).String() != tt.expectedPos.String() { + t.Errorf("Decode() position = %v, want %v", tt.pos.Update(got).String(), tt.expectedPos) } }) } @@ -227,17 +376,17 @@ var ( // Test moves for each position var ( - startMoves = []*Move{ + startMoves = []Move{ {s1: E2, s2: E4}, // e4 {s1: G1, s2: F3}, // Nf3 {s1: B1, s2: C3}, // Nc3 } - midMoves = []*Move{ + midMoves = []Move{ {s1: E1, s2: G1, tags: KingSideCastle}, // O-O {s1: F3, s2: E5, tags: Capture}, // Nxe5 {s1: C4, s2: F7, tags: Check | Capture}, // d4+ } - complexMoves = []*Move{ + complexMoves = []Move{ {s1: B7, s2: B8, promo: Knight}, // b8=N {s1: B7, s2: A8, promo: Bishop, tags: Capture}, // bxa8=B {s1: B7, s2: C8, promo: Rook, tags: Check}, // bxc8=R+ @@ -246,24 +395,35 @@ var ( } ) -// Benchmarks for UCI Notation +func mustEncode(t testing.TB, codec MoveTextCodec, pos *Position, m Move) string { + t.Helper() + s, err := codec.Encode(pos, m) + if err != nil { + t.Fatalf("Encode(%s) from %s: %v", m, pos, err) + } + return s +} + +// Benchmarks for UCI notation func BenchmarkUCIEncode(b *testing.B) { - notation := UCINotation{} + codec := UCI() positions := []*Position{startPos, midPos, complexPos} - moves := [][]*Move{startMoves, midMoves, complexMoves} + moves := [][]Move{startMoves, midMoves, complexMoves} b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { + for i := range b.N { pos := positions[i%len(positions)] move := moves[i%len(moves)][i%len(moves[i%len(moves)])] - notation.Encode(pos, move) + if _, err := codec.Encode(pos, move); err != nil { + b.Fatalf("Encode error: %v", err) + } } } func BenchmarkUCIDecode(b *testing.B) { - notation := UCINotation{} + codec := UCI() samples := []struct { pos *Position text string @@ -276,33 +436,35 @@ func BenchmarkUCIDecode(b *testing.B) { b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { + for i := range b.N { sample := samples[i%len(samples)] - _, err := notation.Decode(sample.pos, sample.text) + _, err := codec.Decode(sample.pos, sample.text) if err != nil { b.Fatalf("error decoding %s: %s", sample.text, err) } } } -// Benchmarks for Algebraic Notation +// Benchmarks for Algebraic notation func BenchmarkAlgebraicEncode(b *testing.B) { - notation := AlgebraicNotation{} + codec := SAN() positions := []*Position{startPos, midPos, complexPos} - moves := [][]*Move{startMoves, midMoves, complexMoves} + moves := [][]Move{startMoves, midMoves, complexMoves} b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { + for i := range b.N { pos := positions[i%len(positions)] move := moves[i%len(moves)][i%len(moves[i%len(moves)])] - notation.Encode(pos, move) + if _, err := codec.Encode(pos, move); err != nil { + b.Fatalf("Encode error: %v", err) + } } } func BenchmarkAlgebraicDecode(b *testing.B) { - notation := AlgebraicNotation{} + codec := SAN() samples := []struct { pos *Position text string @@ -315,33 +477,35 @@ func BenchmarkAlgebraicDecode(b *testing.B) { b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { + for i := range b.N { sample := samples[i%len(samples)] - _, err := notation.Decode(sample.pos, sample.text) + _, err := codec.Decode(sample.pos, sample.text) if err != nil { b.Fatalf("error decoding %s: %s", sample.text, err) } } } -// Benchmarks for Long Algebraic Notation +// Benchmarks for Long Algebraic notation func BenchmarkLongAlgebraicEncode(b *testing.B) { - notation := LongAlgebraicNotation{} + codec := LongAlgebraic() positions := []*Position{startPos, midPos, complexPos} - moves := [][]*Move{startMoves, midMoves, complexMoves} + moves := [][]Move{startMoves, midMoves, complexMoves} b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { + for i := range b.N { pos := positions[i%len(positions)] move := moves[i%len(moves)][i%len(moves[i%len(moves)])] - notation.Encode(pos, move) + if _, err := codec.Encode(pos, move); err != nil { + b.Fatalf("Encode error: %v", err) + } } } func BenchmarkLongAlgebraicDecode(b *testing.B) { - notation := LongAlgebraicNotation{} + codec := LongAlgebraic() samples := []struct { pos *Position text string @@ -354,9 +518,9 @@ func BenchmarkLongAlgebraicDecode(b *testing.B) { b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { + for i := range b.N { sample := samples[i%len(samples)] - _, err := notation.Decode(sample.pos, sample.text) + _, err := codec.Decode(sample.pos, sample.text) if err != nil { b.Fatalf("error decoding %s: %s", sample.text, err) } @@ -365,7 +529,7 @@ func BenchmarkLongAlgebraicDecode(b *testing.B) { // Benchmark specific scenarios func BenchmarkAlgebraicDecodeComplex(b *testing.B) { - notation := AlgebraicNotation{} + codec := SAN() pos := complexPos moves := []string{ "Nxf7", // Capture with check @@ -376,8 +540,8 @@ func BenchmarkAlgebraicDecodeComplex(b *testing.B) { b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { - _, err := notation.Decode(pos, moves[i%len(moves)]) + for i := range b.N { + _, err := codec.Decode(pos, moves[i%len(moves)]) if err != nil { b.Fatalf("error decoding %s: %s", moves[i%len(moves)], err) } @@ -386,36 +550,77 @@ func BenchmarkAlgebraicDecodeComplex(b *testing.B) { func TestPromotionWithCheck(t *testing.T) { promoPos := unsafeFEN("8/1P2k3/8/8/8/8/8/8 w - - 0 1") - promoMove := &Move{s1: B7, s2: B8, promo: Queen, tags: Check} + promoMove := Move{s1: B7, s2: B8, promo: Queen, tags: Check} - algebraicNotation := AlgebraicNotation{} - result := algebraicNotation.Encode(promoPos, promoMove) - if result != "b8=Q+" { - t.Fatalf("Expected 'b8=Q+', got '%s'", result) + got := mustEncode(t, SAN(), promoPos, promoMove) + if got != "b8=Q" { + t.Fatalf("SAN: Expected 'b8=Q', got '%s'", got) } - longAlgebraicNotation := LongAlgebraicNotation{} - result = longAlgebraicNotation.Encode(promoPos, promoMove) - if result != "b7b8=Q+" { - t.Fatalf("Expected 'b7b8=Q+', got '%s'", result) + got = mustEncode(t, LongAlgebraic(), promoPos, promoMove) + if got != "b7b8=Q" { + t.Fatalf("LongAlgebraic: Expected 'b7b8=Q', got '%s'", got) } } func TestPromotionWithCheckFromIssue84(t *testing.T) { promoPos := unsafeFEN("8/1P2k3/8/8/8/8/8/8 w - - 0 1") - promoMove := &Move{s1: B7, s2: B8, promo: Queen} - promoMove.AddTag(Check) + promoMove := Move{s1: B7, s2: B8, promo: Queen}.WithTag(Check) - algebraicNotation := AlgebraicNotation{} - result := algebraicNotation.Encode(promoPos, promoMove) - if result != "b8=Q+" { - t.Fatalf("Algebraic Notation: Expected 'b8=Q+', got '%s'", result) + got := mustEncode(t, SAN(), promoPos, promoMove) + if got != "b8=Q" { + t.Fatalf("SAN: Expected 'b8=Q', got '%s'", got) } - longAlgebraicNotation := LongAlgebraicNotation{} - result = longAlgebraicNotation.Encode(promoPos, promoMove) - if result != "b7b8=Q+" { - t.Fatalf("Long Algebraic Notation: Expected 'b7b8=Q+', got '%s'", result) + got = mustEncode(t, LongAlgebraic(), promoPos, promoMove) + if got != "b7b8=Q" { + t.Fatalf("LongAlgebraic: Expected 'b7b8=Q', got '%s'", got) + } +} + +// Issue 84's original failure was an encoded promotion missing its check +// suffix. The codec now recomputes the Check tag from the resulting position +// (not the input), so this test uses a position where the promotion genuinely +// delivers check: a pawn on b7 promoting on b8 attacks the black king on d8 +// along the 8th rank. +func TestPromotionDeliversGenuineCheck(t *testing.T) { + promoPos := unsafeFEN("3k4/1P6/8/8/8/8/8/4K3 w - - 0 1") + promoMove := Move{s1: B7, s2: B8, promo: Queen} + + got := mustEncode(t, SAN(), promoPos, promoMove) + if got != "b8=Q+" { + t.Fatalf("SAN: Expected 'b8=Q+', got '%s'", got) + } + + got = mustEncode(t, LongAlgebraic(), promoPos, promoMove) + if got != "b7b8=Q+" { + t.Fatalf("LongAlgebraic: Expected 'b7b8=Q+', got '%s'", got) + } +} + +func TestNullMoveEncodeDoesNotRequirePosition(t *testing.T) { + got, err := SAN().Encode(nil, NewNullMove()) + if err != nil { + t.Fatalf("SAN().Encode(nil, null) error = %v", err) + } + if got != "Z0" { + t.Fatalf("SAN().Encode(nil, null) = %q, want %q", got, "Z0") + } + + got, err = LongAlgebraic().Encode(nil, NewNullMove()) + if err != nil { + t.Fatalf("LongAlgebraic().Encode(nil, null) error = %v", err) + } + if got != "0000" { + t.Fatalf("LongAlgebraic().Encode(nil, null) = %q, want %q", got, "0000") + } + + got, err = UCI().Encode(nil, NewNullMove()) + if err != nil { + t.Fatalf("UCI().Encode(nil, null) error = %v", err) + } + if got != "0000" { + t.Fatalf("UCI().Encode(nil, null) = %q, want %q", got, "0000") } } @@ -444,7 +649,7 @@ func TestIssue84FullGame(t *testing.T) { t.Fatalf("Failed to parse PGN: %v", err) } game := NewGame(pgnObj) - moves := game.Moves() + moves := game.MoveTree().MainLine() for i, mv := range moves { moveNum := (i / 2) + 1 @@ -453,44 +658,35 @@ func TestIssue84FullGame(t *testing.T) { color = "B" } - _, err := safeEncode(LongAlgebraicNotation{}, mv.Position(), mv) - if err != nil { - t.Fatalf("Error: LongAlgebraicNotation.Encode panic at half-move %d (%d. %s): %v", + if _, err := LongAlgebraic().Encode(mv.Position(), mv.Move()); err != nil { + t.Fatalf("Error: LongAlgebraic().Encode panic at half-move %d (%d. %s): %v", i, moveNum, color, err) } - _, err = safeEncode(AlgebraicNotation{}, mv.Position(), mv) - if err != nil { - t.Fatalf("Error: AlgebraicNotation.Encode panic at half-move %d (%d. %s): %v", + if _, err := SAN().Encode(mv.Position(), mv.Move()); err != nil { + t.Fatalf("Error: SAN().Encode panic at half-move %d (%d. %s): %v", i, moveNum, color, err) } } } -func safeEncode(notation Encoder, pos *Position, mv *Move) (s string, err error) { - defer func() { - if r := recover(); r != nil { - err = fmt.Errorf("%v", r) - } - }() - return notation.Encode(pos, mv), nil -} - // Benchmark promotion scenarios func BenchmarkPromotionEncoding(b *testing.B) { promoPos := unsafeFEN("rnbqkbnr/pPpppppp/8/8/8/8/P1PPPPPP/RNBQKBNR w KQkq - 0 1") - promoMove := &Move{s1: B7, s2: B8, promo: Queen, tags: Check} - notations := []Notation{ - UCINotation{}, - AlgebraicNotation{}, - LongAlgebraicNotation{}, + promoMove := Move{s1: B7, s2: B8, promo: Queen, tags: Check} + codecs := []MoveTextCodec{ + UCI(), + SAN(), + LongAlgebraic(), } b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { - notation := notations[i%len(notations)] - notation.Encode(promoPos, promoMove) + for i := range b.N { + codec := codecs[i%len(codecs)] + if _, err := codec.Encode(promoPos, promoMove); err != nil { + b.Fatalf("Encode error: %v", err) + } } } diff --git a/null_move_test.go b/null_move_test.go new file mode 100644 index 00000000..aaabf448 --- /dev/null +++ b/null_move_test.go @@ -0,0 +1,491 @@ +package chess_test + +import ( + "fmt" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +// Null move specification +// +// A null move flips the side to move without moving any piece. It is used in +// engines for null-move pruning and in PGN annotations to indicate a side +// passed. The standard PGN format does not define null moves, so this package +// emits "Z0" (the convention used by ChessBase and Scid) and accepts several +// common spellings when reading. +// +// notation contract: +// - SAN encode : "Z0" +// - Long/UCI encode : "0000" +// - SAN decode : "Z0", "Z1", "--", "@@" +// - UCI decode : "0000" +// +// Validation contract: +// - Null moves are never part of a position's legal moves (ValidMoves). +// - Game.Move() rejects a null move. +// - Game.UnsafeMove(NullMove()) and Game.NullMove() accept it. +// +// State changes after a null move: +// - Turn flips. +// - halfMoveClock increments by 1 (treated like a quiet move). +// - moveCount increments by 1 when Black was the side to move. +// - en-passant square is cleared (the capture right expires). +// - castling rights are unchanged. +// - pieces are unchanged. +// - inCheck is recomputed for the new side to move. +// - Zobrist hash reflects the new turn and cleared en-passant. + +func ExampleGame_NullMove() { + g := chess.NewGame() + if _, err := g.NullMove(); err != nil { + fmt.Println("Error:", err) + return + } + // A null move flips the side to move without moving any piece. + fmt.Println(g.Position().Turn()) + // Output: b +} + +// ------------------------------------------------------------------ +// Constructor +// ------------------------------------------------------------------ + +func TestNullMove_ConstructorHasNullTag(t *testing.T) { + m := chess.NewNullMove() + if !m.HasTag(chess.Null) { + t.Fatalf("NullMove() must carry the Null MoveTag") + } +} + +// ------------------------------------------------------------------ +// notation encoding +// ------------------------------------------------------------------ + +func TestNullMove_SANEncode(t *testing.T) { + pos := chess.StartingPosition() + got, err := chess.SAN().Encode(pos, chess.NewNullMove()) + if err != nil { + t.Fatalf("SAN Encode error: %v", err) + } + if got != "Z0" { + t.Fatalf("SAN Encode = %q, want %q", got, "Z0") + } +} + +func TestNullMove_LongAlgebraicEncode(t *testing.T) { + pos := chess.StartingPosition() + got, err := chess.LongAlgebraic().Encode(pos, chess.NewNullMove()) + if err != nil { + t.Fatalf("LongAlgebraic Encode error: %v", err) + } + if got != "0000" { + t.Fatalf("LongAlgebraic Encode = %q, want %q", got, "0000") + } +} + +func TestNullMove_UCIEncode(t *testing.T) { + pos := chess.StartingPosition() + got, err := chess.UCI().Encode(pos, chess.NewNullMove()) + if err != nil { + t.Fatalf("UCI Encode error: %v", err) + } + if got != "0000" { + t.Fatalf("UCI Encode = %q, want %q", got, "0000") + } +} + +// ------------------------------------------------------------------ +// notation decoding +// ------------------------------------------------------------------ + +func TestNullMove_SANDecode(t *testing.T) { + pos := chess.StartingPosition() + cases := []string{"Z0", "Z1", "--", "@@"} + for _, s := range cases { + t.Run(s, func(t *testing.T) { + m, err := chess.SAN().Decode(pos, s) + if err != nil { + t.Fatalf("SAN Decode(%q) error: %v", s, err) + } + if !m.HasTag(chess.Null) { + t.Fatalf("SAN Decode(%q) returned move without Null tag", s) + } + }) + } +} + +func TestNullMove_UCIDecode(t *testing.T) { + pos := chess.StartingPosition() + m, err := chess.UCI().Decode(pos, "0000") + if err != nil { + t.Fatalf("UCI Decode error: %v", err) + } + if !m.HasTag(chess.Null) { + t.Fatalf("UCI Decode of '0000' must return null move") + } +} + +func TestNullMove_LongAlgebraicDecode(t *testing.T) { + pos := chess.StartingPosition() + m, err := chess.LongAlgebraic().Decode(pos, "0000") + if err != nil { + t.Fatalf("LongAlgebraic Decode error: %v", err) + } + if !m.HasTag(chess.Null) { + t.Fatalf("LongAlgebraic Decode of '0000' must return null move") + } +} + +// ------------------------------------------------------------------ +// Position.Update behaviour +// ------------------------------------------------------------------ + +func TestNullMove_UpdateFlipsTurn(t *testing.T) { + pos := chess.StartingPosition() + if pos.Turn() != chess.White { + t.Fatalf("starting position Turn=%v, want White", pos.Turn()) + } + next := pos.Update(chess.NewNullMove()) + if next.Turn() != chess.Black { + t.Fatalf("after null move, Turn=%v, want Black", next.Turn()) + } + // Original is immutable. + if pos.Turn() != chess.White { + t.Fatalf("Update must not mutate the receiver; Turn=%v", pos.Turn()) + } +} + +func TestNullMove_UpdateFlipsTurnTwice(t *testing.T) { + pos := chess.StartingPosition() + pos = pos.Update(chess.NewNullMove()) + pos = pos.Update(chess.NewNullMove()) + if pos.Turn() != chess.White { + t.Fatalf("after two null moves, Turn=%v, want White", pos.Turn()) + } +} + +func TestNullMove_UpdateIncrementsHalfMoveClock(t *testing.T) { + pos := chess.StartingPosition() + if pos.HalfMoveClock() != 0 { + t.Fatalf("starting halfMoveClock=%d, want 0", pos.HalfMoveClock()) + } + next := pos.Update(chess.NewNullMove()) + if next.HalfMoveClock() != 1 { + t.Fatalf("after null move halfMoveClock=%d, want 1", next.HalfMoveClock()) + } +} + +func TestNullMove_UpdateDoesNotChangeBoard(t *testing.T) { + pos := chess.StartingPosition() + next := pos.Update(chess.NewNullMove()) + if next.Board().Draw() != pos.Board().Draw() { + t.Fatalf("board changed after null move:\nbefore=%s\nafter=%s", + pos.Board().Draw(), next.Board().Draw()) + } +} + +func TestNullMove_UpdatePreservesCastleRights(t *testing.T) { + pos := chess.StartingPosition() + next := pos.Update(chess.NewNullMove()) + if next.CastleRights() != pos.CastleRights() { + t.Fatalf("castle rights changed: before=%q after=%q", + pos.CastleRights(), next.CastleRights()) + } +} + +func TestNullMove_UpdateClearsEnPassant(t *testing.T) { + fen := "rnbqkbnr/ppp2ppp/4p3/3pP3/8/8/PPPP1PPP/RNBQKBNR w KQkq d6 0 3" + fenOpt, err := chess.FEN(fen) + if err != nil { + t.Fatalf("FEN parse: %v", err) + } + g := chess.NewGame(fenOpt) + pos := g.Position() + if pos.EnPassantSquare() == chess.NoSquare { + t.Fatalf("setup: en passant square should be set, got %v", pos.EnPassantSquare()) + } + next := pos.Update(chess.NewNullMove()) + if next.EnPassantSquare() != chess.NoSquare { + t.Fatalf("after null move, en passant square = %v, want NoSquare", + next.EnPassantSquare()) + } +} + +func TestNullMove_UpdateKeepsEnPassantCleared(t *testing.T) { + pos := chess.StartingPosition() + if pos.EnPassantSquare() != chess.NoSquare { + t.Fatalf("starting position should have no en passant square") + } + next := pos.Update(chess.NewNullMove()) + if next.EnPassantSquare() != chess.NoSquare { + t.Fatalf("after null move, en passant square should remain NoSquare") + } +} + +func TestNullMove_UpdateChangesHash(t *testing.T) { + pos := chess.StartingPosition() + next := pos.Update(chess.NewNullMove()) + if pos.ZobristHash() == next.ZobristHash() { + t.Fatal("Zobrist hash must change when side to move flips") + } + // Hash must be deterministic: another null move from the new position + // produces the same hash. + next2 := next.Update(chess.NewNullMove()) + if next2.ZobristHash() != pos.ZobristHash() { + t.Fatal("two successive null moves must return to the original hash") + } +} + +func TestNullMove_UpdateIncrementsMoveCountAfterBlack(t *testing.T) { + // Starting with FEN where it's Black to move at move 5. + fen := "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1" + fenOpt, err := chess.FEN(fen) + if err != nil { + t.Fatalf("FEN parse: %v", err) + } + g := chess.NewGame(fenOpt) + pos := g.Position() + if pos.Turn() != chess.Black { + t.Fatalf("setup: Turn=%v, want Black", pos.Turn()) + } + // moveCount is not exported; verify via FEN round trip. + beforeFen := pos.String() + next := pos.Update(chess.NewNullMove()) + afterFen := next.String() + if beforeFen == afterFen { + t.Fatalf("FEN must change after null move\nbefore=%s\nafter=%s", + beforeFen, afterFen) + } + // The "fullmove" component (last token in FEN) must increment by 1 + // because Black's null move ends a full move. + beforeFull := fenField(beforeFen, 5) + afterFull := fenField(afterFen, 5) + if afterFull != beforeFull+1 { + t.Fatalf("fullmove before=%d after=%d, want +1", beforeFull, afterFull) + } +} + +// ------------------------------------------------------------------ +// Game insertion API +// ------------------------------------------------------------------ + +func TestNullMove_GameMoveRejectsNull(t *testing.T) { + g := chess.NewGame() + if _, err := g.Move(chess.NewNullMove(), nil); err == nil { + t.Fatal("Game.Move must reject a null move") + } +} + +func TestNullMove_UnsafeMoveAcceptsNull(t *testing.T) { + g := chess.NewGame() + if _, err := g.UnsafeMove(chess.NewNullMove(), nil); err != nil { + t.Fatalf("Game.UnsafeMove(NullMove()) error: %v", err) + } + if g.Position().Turn() != chess.Black { + t.Fatalf("after null move Turn=%v, want Black", g.Position().Turn()) + } +} + +func TestNullMove_GameNullMoveMethod(t *testing.T) { + g := chess.NewGame() + node, err := g.NullMove() + if err != nil { + t.Fatalf("Game.NullMove error: %v", err) + } + if node == nil { + t.Fatal("Game.NullMove returned nil node") + } + if !node.Move().HasTag(chess.Null) { + t.Fatal("node move must carry the Null tag") + } + if g.Position().Turn() != chess.Black { + t.Fatalf("after Game.NullMove Turn=%v, want Black", g.Position().Turn()) + } +} + +func TestNullMove_AppearsInMoveList(t *testing.T) { + g := chess.NewGame() + if _, err := g.NullMove(); err != nil { + t.Fatalf("Game.NullMove: %v", err) + } + list := g.MoveList() + if len(list) != 1 { + t.Fatalf("len(MoveList)=%d, want 1", len(list)) + } + if !list[0].Move.HasTag(chess.Null) { + t.Fatal("MoveList entry must carry Null tag") + } +} + +// ------------------------------------------------------------------ +// ValidMoves contract: a null move is not legal. +// ------------------------------------------------------------------ + +func TestNullMove_NeverInValidMoves(t *testing.T) { + g := chess.NewGame() + for _, m := range g.ValidMoves() { + if m.HasTag(chess.Null) { + t.Fatal("ValidMoves must never return a null move") + } + } +} + +// ------------------------------------------------------------------ +// PGN read: token recognition +// ------------------------------------------------------------------ + +func TestNullMove_PGNRead_Z0(t *testing.T) { + // After "1. e4" it's Black's turn; Black plays Z0 (pass), then it's + // White's turn at move 2; White plays Nf3. + pgn := withMinimalTags("1. e4 Z0 2. Nf3 *") + g := mustParseSingleGame(t, pgn) + moves := g.Moves() + if len(moves) != 3 { + t.Fatalf("len(Moves)=%d, want 3 (e4, Z0, Nf3)", len(moves)) + } + if !moves[1].HasTag(chess.Null) { + t.Fatal("second move must be a null move") + } + if g.Position().Turn() != chess.Black { + t.Fatalf("after 1.e4 Z0 2.Nf3, Turn=%v, want Black", g.Position().Turn()) + } +} + +func TestNullMove_PGNRead_DoubleDash(t *testing.T) { + // '--' must be parsed as a null move. + pgn := withMinimalTags("1. e4 -- 2. Nf3 *") + g := mustParseSingleGame(t, pgn) + moves := g.Moves() + if len(moves) != 3 { + t.Fatalf("len(Moves)=%d, want 3", len(moves)) + } + if !moves[1].HasTag(chess.Null) { + t.Fatal("'--' must be parsed as a null move") + } +} + +func TestNullMove_PGNRead_AtStart(t *testing.T) { + pgn := withMinimalTags("1. Z0 e5 *") + g := mustParseSingleGame(t, pgn) + moves := g.Moves() + if len(moves) != 2 { + t.Fatalf("len(Moves)=%d, want 2", len(moves)) + } + if !moves[0].HasTag(chess.Null) { + t.Fatal("first move must be a null move") + } +} + +// TestNullMove_PGNRead_AliasedSpellings covers the PGN-layer spellings not +// covered by TestNullMove_PGNRead_Z0 / DoubleDash: "Z1", "@@", "0000". The +// lexer's readNullMove accepts all five spellings; Z0 and "--" are tested +// individually above, this pins the remaining three at the PGN layer. +func TestNullMove_PGNRead_AliasedSpellings(t *testing.T) { + for _, spelling := range []string{"Z1", "@@", "0000"} { + t.Run(spelling, func(t *testing.T) { + pgn := withMinimalTags("1. e4 " + spelling + " 2. Nf3 *") + g := mustParseSingleGame(t, pgn) + moves := g.Moves() + if len(moves) != 3 { + t.Fatalf("len(Moves)=%d, want 3 (e4, %s, Nf3)", len(moves), spelling) + } + if !moves[1].HasTag(chess.Null) { + t.Fatalf("%q must be parsed as a null move", spelling) + } + }) + } +} + +func TestNullMove_PGNRead_TwoConsecutiveNulls(t *testing.T) { + // White passes, Black passes: side to move is back to White at move 2. + pgn := withMinimalTags("1. Z0 Z0 *") + g := mustParseSingleGame(t, pgn) + moves := g.Moves() + if len(moves) != 2 { + t.Fatalf("len(Moves)=%d, want 2", len(moves)) + } + for i, m := range moves { + if !m.HasTag(chess.Null) { + t.Fatalf("move %d must be null", i) + } + } + if g.Position().Turn() != chess.White { + t.Fatalf("after 1.Z0 Z0, Turn=%v, want White", g.Position().Turn()) + } +} + +// ------------------------------------------------------------------ +// PGN write + read round trip +// ------------------------------------------------------------------ + +func TestNullMove_PGNWrite(t *testing.T) { + g := chess.NewGame() + if _, err := g.NullMove(); err != nil { + t.Fatalf("NullMove: %v", err) + } + if _, err := g.MoveText("e5", chess.SAN(), nil); err != nil { + t.Fatalf("PushMove e5: %v", err) + } + rendered := g.String() + if !strings.Contains(rendered, " Z0 ") { + t.Fatalf("rendered PGN should contain Z0, got:\n%s", rendered) + } +} + +func TestNullMove_PGNWriteReadRoundTrip(t *testing.T) { + g := chess.NewGame() + if _, err := g.NullMove(); err != nil { + t.Fatalf("NullMove: %v", err) + } + if _, err := g.MoveText("e5", chess.SAN(), nil); err != nil { + t.Fatalf("PushMove e5: %v", err) + } + if _, err := g.MoveText("Nf3", chess.SAN(), nil); err != nil { + t.Fatalf("PushMove Nf3: %v", err) + } + if _, err := g.NullMove(); err != nil { + t.Fatalf("NullMove (tail): %v", err) + } + rendered := g.String() + + loaded, err := chess.ParsePGN(strings.NewReader(rendered)) + if err != nil { + t.Fatalf("re-parse: %v", err) + } + moves := loaded.Moves() + if len(moves) != 4 { + t.Fatalf("len(Moves)=%d, want 4", len(moves)) + } + if !moves[0].HasTag(chess.Null) { + t.Fatal("round-tripped first move must be null") + } + if !moves[3].HasTag(chess.Null) { + t.Fatal("round-tripped last move must be null") + } + // Z0 e5 Nf3 Z0: White pass, Black e5, White Nf3, Black pass -> White to move. + if loaded.Position().Turn() != chess.White { + t.Fatalf("after round-trip, Turn=%v, want White", loaded.Position().Turn()) + } +} + +// ------------------------------------------------------------------ +// helpers +// ------------------------------------------------------------------ + +// fenField splits a FEN string and returns the 0-indexed field as an int. +func fenField(fen string, idx int) int { + parts := strings.Split(fen, " ") + if idx >= len(parts) { + return 0 + } + n := 0 + for _, c := range parts[idx] { + if c < '0' || c > '9' { + return 0 + } + n = n*10 + int(c-'0') + } + return n +} diff --git a/opening/README.md b/opening/README.md index 31961d86..e750852b 100644 --- a/opening/README.md +++ b/opening/README.md @@ -22,8 +22,8 @@ import ( func main(){ g := chess.NewGame() - g.PushNotationMove("e4", chess.AlgebraicNotation{}, nil) - g.PushNotationMove("e6", chess.AlgebraicNotation{}, nil) + g.MoveText("e4", chess.SAN(), nil) + g.MoveText("e6", chess.SAN(), nil) // print French Defense book := opening.NewBookECO() diff --git a/opening/eco.go b/opening/eco.go index 92c15256..7eddd585 100644 --- a/opening/eco.go +++ b/opening/eco.go @@ -3,17 +3,18 @@ package opening import ( "bytes" "encoding/csv" + "errors" "fmt" "io" "strings" "sync" - "github.com/corentings/chess/v2" + "github.com/corentings/chess/v3" ) var ( + errDefaultBook error defaultBook *BookECO - defaultBookErr error defaultBookOnce sync.Once ) @@ -22,9 +23,9 @@ var ( // It is safe for concurrent use. func DefaultBook() (*BookECO, error) { defaultBookOnce.Do(func() { - defaultBook, defaultBookErr = NewBook(bytes.NewReader(ecoData)) + defaultBook, errDefaultBook = NewBook(bytes.NewReader(ecoData)) }) - return defaultBook, defaultBookErr + return defaultBook, errDefaultBook } // BookECO represents the Encyclopedia of Chess Openings https://en.wikipedia.org/wiki/Encyclopaedia_of_Chess_Openings @@ -36,47 +37,46 @@ type BookECO struct { // NewBook creates a new opening book from an ECO TSV reader. // Use this for custom opening data or when you need isolation from the default book. +// NewBook validates the input during construction so malformed books fail +// before use. Entry.Game returns a caller-owned clone of the cached game. func NewBook(r io.Reader) (*BookECO, error) { b := &BookECO{ root: &node{ - children: map[string]*node{}, + children: map[uint32]*node{}, pos: chess.NewGame().Position(), }, startingPosition: chess.NewGame().Position(), } csvReader := csv.NewReader(r) csvReader.Comma = '\t' + csvReader.FieldsPerRecord = -1 records, err := csvReader.ReadAll() if err != nil { return nil, fmt.Errorf("opening: failed to parse ECO data: %w", err) } for i, row := range records { + rowNum := i + 1 if i == 0 { continue // skip header } if len(row) < 4 { - continue // skip malformed rows + return nil, fmt.Errorf("opening: ECO row %d: expected at least 4 columns, got %d", rowNum, len(row)) } - o := newOpening(row[0], row[1], row[3]) - if err := b.insert(o); err != nil { - return nil, fmt.Errorf("opening: failed to insert opening %s: %w", o.code, err) + moveList := parseMoveList(row[3]) + o, oErr := newEntry(row[0], row[1], row[3], moveList) + if oErr != nil { + return nil, fmt.Errorf("opening: ECO row %d (%s %s): %w", rowNum, row[0], row[1], oErr) + } + if err = b.insertOpening(o); err != nil { + return nil, fmt.Errorf("opening: ECO row %d (%s %s): %w", rowNum, row[0], row[1], err) } } return b, nil } -// NewBookECO returns a new BookECO using the default embedded ECO data. -// Deprecated: Use DefaultBook() for the standard book or NewBook() for custom data. -func NewBookECO() *BookECO { - b, err := DefaultBook() - if err != nil { - panic(err) - } - return b -} - // Find implements the Book interface. -func (b *BookECO) Find(moves []*chess.Move) *Opening { +// Use Find for performance-sensitive opening detection paths. +func (b *BookECO) Find(moves []chess.Move) *Entry { for n := b.followPath(b.root, moves); n != nil; n = n.parent { if n.opening != nil { return n.opening @@ -86,94 +86,103 @@ func (b *BookECO) Find(moves []*chess.Move) *Opening { } // Possible implements the Book interface. -func (b *BookECO) Possible(moves []*chess.Move) []*Opening { - n := b.followPath(b.root, moves) - var openings []*Opening - for _, n := range b.nodeList(n) { - if n.opening != nil { - openings = append(openings, n.opening) - } - } +// Use Possible for performance-sensitive opening exploration paths. +func (b *BookECO) Possible(moves []chess.Move) []*Entry { + root := b.followPath(b.root, moves) + var openings []*Entry + b.collectOpenings(root, &openings) return openings } -func (b *BookECO) followPath(n *node, moves []*chess.Move) *node { +// collectOpenings walks the subtree rooted at n and appends each node's +// opening (if any) directly into the result slice, avoiding the intermediate +// []*node allocation that nodeList/collectNodes used to require. +func (b *BookECO) collectOpenings(n *node, result *[]*Entry) { + if n.opening != nil { + *result = append(*result, n.opening) + } + for _, c := range n.children { + b.collectOpenings(c, result) + } +} + +func (b *BookECO) followPath(n *node, moves []chess.Move) *node { if len(moves) == 0 { return n } - c, ok := n.children[moves[0].String()] + c, ok := n.children[moveKey(moves[0])] if !ok { return n } return b.followPath(c, moves[1:]) } -func (b *BookECO) insert(o *Opening) error { - posList := []*chess.Position{b.startingPosition} - var moves []*chess.Move - for _, s := range parseMoveList(o.pgn) { - pos := posList[len(posList)-1] - m, err := chess.UCINotation{}.Decode(pos, s) - if err != nil { - return fmt.Errorf("error decoding move %s: %w", s, err) - } - moves = append(moves, m) - posList = append(posList, pos.Update(m)) +func (b *BookECO) insertOpening(o *Entry) error { + if len(o.moveList) == 0 { + return errors.New("chess: opening has no moves") } + n := b.root - b.ins(n, o, posList[1:], moves) - return nil -} + for _, moveStr := range o.moveList { + m, err := chess.UCI().Decode(n.pos, moveStr) + if err != nil { + return fmt.Errorf("decode move %s: %w", moveStr, err) + } + key := moveKey(m) + if child, ok := n.children[key]; ok { + n = child + continue + } -func (b *BookECO) ins(n *node, o *Opening, posList []*chess.Position, moves []*chess.Move) { - pos := posList[0] - move := moves[0] - moveStr := move.String() - var child *node - for mv, c := range n.children { - if mv == moveStr { - child = c - break + if !isLegalMove(n.pos, m) { + return fmt.Errorf("apply move %s: move is not valid for the current position", moveStr) } - } - if child == nil { - child = &node{ + + child := &node{ parent: n, - children: map[string]*node{}, - pos: pos, + children: map[uint32]*node{}, + pos: n.pos.Update(m), } - n.children[moveStr] = child - } - if len(posList) == 1 { - child.opening = o - return + n.children[key] = child + n = child } - b.ins(child, o, posList[1:], moves[1:]) + n.opening = o + return nil } -type node struct { - parent *node - children map[string]*node - opening *Opening - pos *chess.Position +func isLegalMove(pos *chess.Position, move chess.Move) bool { + for _, validMove := range pos.ValidMovesUnsafe() { + if validMove.S1() == move.S1() && validMove.S2() == move.S2() && validMove.Promo() == move.Promo() { + return true + } + } + return false } -func (b *BookECO) nodeList(root *node) []*node { - var result []*node - b.collectNodes(root, &result) - return result +// Bit layout for moveKey: a Square fits in 6 bits (0..63), a PieceType fits +// in the low 3 bits of the second 6-bit field. The packed key is therefore +// S1 | S2<<6 | Promo<<12 (18 bits total, fits in a uint32). +const ( + moveKeySquareBits = 6 + moveKeyPromoShift = moveKeySquareBits * 2 +) + +func moveKey(move chess.Move) uint32 { + return uint32(move.S1()) | + uint32(move.S2())<= 5 { + outcome = Draw + method = FivefoldRepetition + } + + if !rules.ignoreSeventyFiveMove && pos.halfMoveClock >= 150 { + outcome = Draw + method = SeventyFiveMoveRule + } + + if !rules.ignoreInsufficient && !pos.board.hasSufficientMaterial() { + outcome = Draw + method = InsufficientMaterial + } + + return outcome, method +} + +// fullOutcomeRules builds the Full ruleset from a Game's ignore flags. It is +// the translation layer between the public functional-option API on Game and +// the pure classifyOutcome policy. +func fullOutcomeRules(g *Game) outcomeRules { + return outcomeRules{ + includeAutoDraws: true, + ignoreFivefold: g.ignoreFivefoldRepetitionDraw, + ignoreSeventyFiveMove: g.ignoreSeventyFiveMoveRuleDraw, + ignoreInsufficient: g.ignoreInsufficientMaterialDraw, + } +} + +// arbitratePGNOutcome reconciles the three outcome sources visible during PGN +// parsing: the board-derived terminal outcome (checkmate/stalemate only, since +// PGN parsing uses the Terminal-only classifyOutcome policy), the Result tag, +// and the movetext result token (1-0 / 0-1 / 1/2-1/2 / *). +// +// Precedence: a board-terminal outcome wins and conflicts with tag/token are +// errors; otherwise the movetext token wins; otherwise the Result tag wins; +// otherwise NoOutcome. The returned error's message is preserved verbatim by +// the parser when it wraps the error into *ParserError. +// +// Pure: no Game state, no allocation on the success path. The parser owns the +// side effect of writing the result back onto the Game. +func arbitratePGNOutcome(boardOutcome Outcome, boardMethod Method, tagOutcome, tokenOutcome Outcome) (Outcome, Method, error) { + boardTerminal := boardMethod == Checkmate || boardMethod == Stalemate + + if boardTerminal { + if tokenOutcome != NoOutcome && tokenOutcome != boardOutcome { + return NoOutcome, NoMethod, errors.New("movetext result token conflicts with board-derivable outcome") + } + if tagOutcome != NoOutcome && tagOutcome != boardOutcome { + return NoOutcome, NoMethod, errors.New("result tag conflicts with board-derivable outcome") + } + return boardOutcome, boardMethod, nil + } + + if tokenOutcome != NoOutcome { + if tagOutcome != NoOutcome && tagOutcome != tokenOutcome { + return NoOutcome, NoMethod, errors.New("movetext result token conflicts with Result tag") + } + return tokenOutcome, NoMethod, nil + } + + if tagOutcome != NoOutcome { + return tagOutcome, NoMethod, nil + } + + return NoOutcome, NoMethod, nil +} diff --git a/outcome_internal_test.go b/outcome_internal_test.go new file mode 100644 index 00000000..aaee7559 --- /dev/null +++ b/outcome_internal_test.go @@ -0,0 +1,153 @@ +package chess + +import ( + "strings" + "testing" +) + +func TestClassifyOutcome(t *testing.T) { + mateBlackMated := "r1bqkb1r/pppp1Qpp/2n2n2/4p3/2B1P3/8/PPPP1PPP/RNB1K1NR b KQkq - 0 4" // Qxf7#, black mated -> WhiteWon + mateWhiteMated := "rnb1kbnr/pppp1ppp/8/4p3/6Pq/5P2/PPPPP2P/RNBQKBNR w KQkq - 0 3" // fool's mate, white mated -> BlackWon + stalemate := "5k2/5P2/5K2/8/8/8/8/8 b - - 0 1" + kvk0 := "8/8/8/3k4/3K4/8/8/8 w - - 0 60" // insufficient material, isolated (clock 0) + kvk150 := "8/8/8/3k4/3K4/8/8/8 w - - 150 60" // insufficient + clock 150 (precedence) + rook := "4k3/8/8/8/8/8/8/R3K3 w - - 10 60" // sufficient material, no mate + rook75 := "4k3/8/8/8/8/8/8/R3K3 w - - 150 60" // sufficient material, clock 150 + + full := func(overrides ...func(*outcomeRules)) outcomeRules { + r := outcomeRules{includeAutoDraws: true} + for _, o := range overrides { + o(&r) + } + return r + } + withIgnoreFivefold := func(r *outcomeRules) { r.ignoreFivefold = true } + withIgnore75 := func(r *outcomeRules) { r.ignoreSeventyFiveMove = true } + withIgnoreInsufficient := func(r *outcomeRules) { r.ignoreInsufficient = true } + + tests := []struct { + name string + fen string + repetitions int + rules outcomeRules + wantOutcome Outcome + wantMethod Method + }{ + // Terminal outcomes (present in both Full and Terminal-only). + {"checkmate white wins", mateBlackMated, 0, outcomeRules{}, WhiteWon, Checkmate}, + {"checkmate black wins", mateWhiteMated, 0, outcomeRules{}, BlackWon, Checkmate}, + {"checkmate white wins full", mateBlackMated, 5, full(), WhiteWon, Checkmate}, // mate short-circuits, draws ignored + {"stalemate", stalemate, 0, outcomeRules{}, Draw, Stalemate}, + + // Automatic draws (Full only). + {"fivefold", rook, 5, full(), Draw, FivefoldRepetition}, + {"fivefold ignored", rook, 5, full(withIgnoreFivefold), NoOutcome, NoMethod}, + {"fivefold below threshold", rook, 4, full(), NoOutcome, NoMethod}, + {"seventyfive move", rook75, 0, full(), Draw, SeventyFiveMoveRule}, + {"seventyfive move ignored", rook75, 0, full(withIgnore75), NoOutcome, NoMethod}, + {"insufficient material", kvk0, 0, full(), Draw, InsufficientMaterial}, + {"insufficient material ignored", kvk0, 0, full(withIgnoreInsufficient), NoOutcome, NoMethod}, + + // Terminal-only policy never emits automatic draws. + {"terminal only skips all draws", kvk150, 5, outcomeRules{}, NoOutcome, NoMethod}, + + // Precedence: when fivefold, 75-move and insufficient all apply, + // InsufficientMaterial wins (it is evaluated last). + {"precedence insufficient wins", kvk150, 5, full(), Draw, InsufficientMaterial}, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + pos, err := decodeFEN(tt.fen) + if err != nil { + t.Fatalf("decodeFEN(%q): %v", tt.fen, err) + } + if pos == nil { + t.Fatalf("decodeFEN(%q) returned nil position", tt.fen) + } + // decodeFEN does not populate inCheck; production callers always + // have it set (FEN option / move application), so mirror that here + // so Status() can detect checkmate. + pos.inCheck = isInCheck(pos) + gotOutcome, gotMethod := classifyOutcome(pos, tt.repetitions, tt.rules) + if gotOutcome != tt.wantOutcome || gotMethod != tt.wantMethod { + t.Errorf("classifyOutcome = (%s, %s), want (%s, %s)", gotOutcome, gotMethod, tt.wantOutcome, tt.wantMethod) + } + }) + } +} + +func TestArbitratePGNOutcome(t *testing.T) { + tests := []struct { + name string + boardOutcome Outcome + boardMethod Method + tagOutcome Outcome + tokenOutcome Outcome + wantOutcome Outcome + wantMethod Method + wantConflict bool + wantConflictSubstr string + }{ + // No sources: NoOutcome / NoMethod. + {"all empty", NoOutcome, NoMethod, NoOutcome, NoOutcome, NoOutcome, NoMethod, false, ""}, + + // Empty / unknown result spellings are treated as NoOutcome (no conflict). + {"unknown tag normalised", NoOutcome, NoMethod, NoOutcome, NoOutcome, NoOutcome, NoMethod, false, ""}, + {"unknown token normalised", NoOutcome, NoMethod, NoOutcome, NoOutcome, NoOutcome, NoMethod, false, ""}, + + // Tag only. + {"tag white wins", NoOutcome, NoMethod, WhiteWon, NoOutcome, WhiteWon, NoMethod, false, ""}, + {"tag draw", NoOutcome, NoMethod, Draw, NoOutcome, Draw, NoMethod, false, ""}, + {"tag black wins", NoOutcome, NoMethod, BlackWon, NoOutcome, BlackWon, NoMethod, false, ""}, + + // Token only. + {"token white wins", NoOutcome, NoMethod, NoOutcome, WhiteWon, WhiteWon, NoMethod, false, ""}, + {"token draw", NoOutcome, NoMethod, NoOutcome, Draw, Draw, NoMethod, false, ""}, + + // Token beats tag when they agree. + {"tag and token agree", NoOutcome, NoMethod, WhiteWon, WhiteWon, WhiteWon, NoMethod, false, ""}, + + // Token and tag conflict (no board). + {"token conflicts with tag", NoOutcome, NoMethod, BlackWon, WhiteWon, NoOutcome, NoMethod, true, "movetext result token conflicts with Result tag"}, + + // Board-terminal wins over tag/token. + {"board checkmate beats agreeing tag and token", WhiteWon, Checkmate, WhiteWon, WhiteWon, WhiteWon, Checkmate, false, ""}, + {"board stalemate beats agreeing tag and token", Draw, Stalemate, Draw, Draw, Draw, Stalemate, false, ""}, + {"board terminal tag omitted token omitted", WhiteWon, Checkmate, NoOutcome, NoOutcome, WhiteWon, Checkmate, false, ""}, + + // Board-terminal conflict with token. + {"board checkmate conflicts with token", WhiteWon, Checkmate, NoOutcome, BlackWon, NoOutcome, NoMethod, true, "movetext result token conflicts with board-derivable outcome"}, + // Board-terminal conflict with tag (token agrees). + {"board checkmate conflicts with tag", WhiteWon, Checkmate, BlackWon, WhiteWon, NoOutcome, NoMethod, true, "result tag conflicts with board-derivable outcome"}, + + // Non-terminal board method (e.g. Resignation carried on a FEN-rooted + // game — shouldn't normally happen at PGN parse since the policy is + // Terminal-only, but the function must not treat it as terminal). + {"non-terminal board method ignored", NoOutcome, Resignation, NoOutcome, WhiteWon, WhiteWon, NoMethod, false, ""}, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + gotOutcome, gotMethod, err := arbitratePGNOutcome(tt.boardOutcome, tt.boardMethod, tt.tagOutcome, tt.tokenOutcome) + if tt.wantConflict { + if err == nil { + t.Fatalf("expected conflict error, got nil") + } + if !strings.Contains(err.Error(), tt.wantConflictSubstr) { + t.Errorf("error = %q, want substring %q", err.Error(), tt.wantConflictSubstr) + } + if gotOutcome != NoOutcome || gotMethod != NoMethod { + t.Errorf("conflict returned (%s, %s), want (NoOutcome, NoMethod)", gotOutcome, gotMethod) + } + return + } + if err != nil { + t.Fatalf("unexpected error: %v", err) + } + if gotOutcome != tt.wantOutcome || gotMethod != tt.wantMethod { + t.Errorf("arbitratePGNOutcome = (%s, %s), want (%s, %s)", gotOutcome, gotMethod, tt.wantOutcome, tt.wantMethod) + } + }) + } +} diff --git a/outcome_types.go b/outcome_types.go new file mode 100644 index 00000000..460707f5 --- /dev/null +++ b/outcome_types.go @@ -0,0 +1,96 @@ +package chess + +import "fmt" + +// A Outcome is the result of a game. +type Outcome int8 + +const ( + // NoOutcome indicates that a game is in progress or ended without a result. + NoOutcome Outcome = iota + // WhiteWon indicates that white won the game. + WhiteWon + // BlackWon indicates that black won the game. + BlackWon + // Draw indicates that game was a draw. + Draw +) + +// String implements the fmt.Stringer interface and returns the PGN result token. +func (o Outcome) String() string { + switch o { + case NoOutcome: + return "*" + case WhiteWon: + return "1-0" + case BlackWon: + return "0-1" + case Draw: + return "1/2-1/2" + } + return "*" +} + +// MarshalText implements the encoding.TextMarshaler interface using the PGN +// result token. +func (o Outcome) MarshalText() ([]byte, error) { + return []byte(o.String()), nil +} + +// UnmarshalText implements the encoding.TextUnmarshaler interface from a PGN +// result token. +func (o *Outcome) UnmarshalText(text []byte) error { + parsed, err := ParseOutcome(string(text)) + if err != nil { + return err + } + *o = parsed + return nil +} + +// ParseOutcome converts a PGN result token into a typed Outcome. Unknown +// tokens return an error. +func ParseOutcome(s string) (Outcome, error) { + switch s { + case "*", "", "?": + return NoOutcome, nil + case "1-0": + return WhiteWon, nil + case "0-1": + return BlackWon, nil + case "1/2-1/2": + return Draw, nil + } + return NoOutcome, fmt.Errorf("chess: invalid outcome %q", s) +} + +// A Method is the method that generated the outcome. +type Method uint8 + +const ( + // NoMethod indicates that an outcome hasn't occurred or that the method can't be determined. + NoMethod Method = iota + // Checkmate indicates that the game was won checkmate. + Checkmate + // Resignation indicates that the game was won by resignation. + Resignation + // DrawOffer indicates that the game was drawn by a draw offer. + DrawOffer + // Stalemate indicates that the game was drawn by stalemate. + Stalemate + // ThreefoldRepetition indicates that the game was drawn when the game + // state was repeated three times and a player requested a draw. + ThreefoldRepetition + // FivefoldRepetition indicates that the game was automatically drawn + // by the game state being repeated five times. + FivefoldRepetition + // FiftyMoveRule indicates that the game was drawn by the half + // move clock being one hundred or greater when a player requested a draw. + FiftyMoveRule + // SeventyFiveMoveRule indicates that the game was automatically drawn + // when the half move clock was one hundred and fifty or greater. + SeventyFiveMoveRule + // InsufficientMaterial indicates that the game was automatically drawn + // because there was insufficient material for checkmate. + InsufficientMaterial +) diff --git a/outcome_types_test.go b/outcome_types_test.go new file mode 100644 index 00000000..638fccc2 --- /dev/null +++ b/outcome_types_test.go @@ -0,0 +1,34 @@ +package chess + +import ( + "testing" +) + +func TestOutcomeStringAndParse(t *testing.T) { + cases := []struct { + o Outcome + token string + valid bool + }{ + {NoOutcome, "*", true}, + {WhiteWon, "1-0", true}, + {BlackWon, "0-1", true}, + {Draw, "1/2-1/2", true}, + } + for _, c := range cases { + if got := c.o.String(); got != c.token { + t.Errorf("%v.String() = %q, want %q", c.o, got, c.token) + } + got, err := ParseOutcome(c.token) + if err != nil { + t.Errorf("ParseOutcome(%q) error = %v", c.token, err) + } + if got != c.o { + t.Errorf("ParseOutcome(%q) = %v, want %v", c.token, got, c.o) + } + } + + if _, err := ParseOutcome("banana"); err == nil { + t.Fatal("expected error for invalid outcome") + } +} diff --git a/patterns.go b/patterns.go new file mode 100644 index 00000000..9c8953d3 --- /dev/null +++ b/patterns.go @@ -0,0 +1,221 @@ +package chess + +import ( + "math/bits" +) + +const ( + bbFileA bitboard = 9259542123273814144 + bbFileB bitboard = 4629771061636907072 + bbFileC bitboard = 2314885530818453536 + bbFileD bitboard = 1157442765409226768 + bbFileE bitboard = 578721382704613384 + bbFileF bitboard = 289360691352306692 + bbFileG bitboard = 144680345676153346 + bbFileH bitboard = 72340172838076673 + + bbRank1 bitboard = 18374686479671623680 + bbRank2 bitboard = 71776119061217280 + bbRank3 bitboard = 280375465082880 + bbRank4 bitboard = 1095216660480 + bbRank5 bitboard = 4278190080 + bbRank6 bitboard = 16711680 + bbRank7 bitboard = 65280 + bbRank8 bitboard = 255 +) + +// bbForSquare returns the bitboard mask for the given square. +// This is a package-level function rather than a Square method because it +// accesses the package-level lookup table bbSquares. +func bbForSquare(sq Square) bitboard { + return bbSquares[sq] +} + +// Lookup tables for piece movement patterns and board masks. +// +//nolint:gochecknoglobals // this is a lookup table +var ( + bbKnightMoves = [64]bitboard{9077567998918656, 4679521487814656, 38368557762871296, 19184278881435648, 9592139440717824, 4796069720358912, 2257297371824128, 1128098930098176, 2305878468463689728, 1152939783987658752, 9799982666336960512, 4899991333168480256, 2449995666584240128, 1224997833292120064, 576469569871282176, 288234782788157440, 4620693356194824192, 11533718717099671552, 5802888705324613632, 2901444352662306816, 1450722176331153408, 725361088165576704, 362539804446949376, 145241105196122112, 18049583422636032, 45053588738670592, 22667534005174272, 11333767002587136, 5666883501293568, 2833441750646784, 1416171111120896, 567348067172352, 70506185244672, 175990581010432, 88545054707712, 44272527353856, 22136263676928, 11068131838464, 5531918402816, 2216203387392, 275414786112, 687463207072, 345879119952, 172939559976, 86469779988, 43234889994, 21609056261, 8657044482, 1075839008, 2685403152, 1351090312, 675545156, 337772578, 168886289, 84410376, 33816580, 4202496, 10489856, 5277696, 2638848, 1319424, 659712, 329728, 132096} + + bbKingMoves = [64]bitboard{4665729213955833856, 11592265440851656704, 5796132720425828352, 2898066360212914176, 1449033180106457088, 724516590053228544, 362258295026614272, 144959613005987840, 13853283560024178688, 16186183351374184448, 8093091675687092224, 4046545837843546112, 2023272918921773056, 1011636459460886528, 505818229730443264, 216739030602088448, 54114388906344448, 63227278716305408, 31613639358152704, 15806819679076352, 7903409839538176, 3951704919769088, 1975852459884544, 846636838289408, 211384331665408, 246981557485568, 123490778742784, 61745389371392, 30872694685696, 15436347342848, 7718173671424, 3307175149568, 825720045568, 964771708928, 482385854464, 241192927232, 120596463616, 60298231808, 30149115904, 12918652928, 3225468928, 3768639488, 1884319744, 942159872, 471079936, 235539968, 117769984, 50463488, 12599488, 14721248, 7360624, 3680312, 1840156, 920078, 460039, 197123, 49216, 57504, 28752, 14376, 7188, 3594, 1797, 770} + + bbSquares = [64]bitboard{} + alignedMasks = [64]bitboard{} + betweenMasks = [64][64]bitboard{} + rayFileSteps = [64][64]int8{} + rayRankSteps = [64][64]int8{} + rayDiagonals = [64][64]bool{} +) + +// bbForPossibleMoves returns a bitboard with 1s in positions where the piece +// of the given type at the given square can potentially move, without considering +// whether the moves would be legal (e.g., leave the king in check). +// +// The function handles movement patterns for: +// - King: One square in any direction +// - Queen: Sliding moves in all directions +// - Rook: Sliding moves horizontally and vertically +// - Bishop: Sliding moves diagonally +// - Knight: L-shaped jumps +// - Pawn: Forward moves and captures, including en passant +func bbForPossibleMoves(pos *Position, pt PieceType, sq Square) bitboard { + switch pt { + case King: + return bbKingMoves[sq] + case Queen: + return diaAttack(^pos.board.emptySqs, sq) | hvAttack(^pos.board.emptySqs, sq) + case Rook: + return hvAttack(^pos.board.emptySqs, sq) + case Bishop: + return diaAttack(^pos.board.emptySqs, sq) + case Knight: + return bbKnightMoves[sq] + case Pawn: + return pawnMoves(pos, sq) + } + return bitboard(0) +} + +// pawnMoves returns a bitboard with 1s in positions where the pawn at the +// given square can potentially move. +// +// The function considers: +// - Single and double forward moves +// - Diagonal captures +// - En passant captures +// +//nolint:mnd // this is a formula to determine the color of a square +func pawnMoves(pos *Position, sq Square) bitboard { + bb := bbForSquare(sq) + var bbEnPassant bitboard + if pos.enPassantSquare != NoSquare { + bbEnPassant = bbForSquare(pos.enPassantSquare) + } + if pos.Turn() == White { + capRight := ((bb & ^bbFileH & ^bbRank8) >> 9) & (pos.board.blackSqs | bbEnPassant) + capLeft := ((bb & ^bbFileA & ^bbRank8) >> 7) & (pos.board.blackSqs | bbEnPassant) + upOne := ((bb & ^bbRank8) >> 8) & pos.board.emptySqs + upTwo := ((upOne & bbRank3) >> 8) & pos.board.emptySqs + return capRight | capLeft | upOne | upTwo + } + capRight := ((bb & ^bbFileH & ^bbRank1) << 7) & (pos.board.whiteSqs | bbEnPassant) + capLeft := ((bb & ^bbFileA & ^bbRank1) << 9) & (pos.board.whiteSqs | bbEnPassant) + upOne := ((bb & ^bbRank1) << 8) & pos.board.emptySqs + upTwo := ((upOne & bbRank6) << 8) & pos.board.emptySqs + return capRight | capLeft | upOne | upTwo +} + +func rayStep(from Square, to Square) (int, int, bool) { + fileDelta := int(to.File()) - int(from.File()) + rankDelta := int(to.Rank()) - int(from.Rank()) + switch { + case fileDelta == 0: + return 0, compareStep(rankDelta, 0), false + case rankDelta == 0: + return compareStep(fileDelta, 0), 0, false + case abs(fileDelta) == abs(rankDelta): + return compareStep(fileDelta, 0), compareStep(rankDelta, 0), true + default: + return 0, 0, false + } +} + +func piecePinsAlong(pt PieceType, diagonal bool) bool { + if pt == Queen { + return true + } + if diagonal { + return pt == Bishop + } + return pt == Rook +} + +func squaresBetween(a Square, b Square) bitboard { + fileStep := compareStep(int(b.File()), int(a.File())) + rankStep := compareStep(int(b.Rank()), int(a.Rank())) + if fileStep == 0 && rankStep == 0 { + return 0 + } + if fileStep != 0 && rankStep != 0 && !sameDiagonal(a, b) { + return 0 + } + var out bitboard + file := int(a.File()) + fileStep + rank := int(a.Rank()) + rankStep + for file != int(b.File()) || rank != int(b.Rank()) { + out |= bbForSquare(NewSquare(File(file), Rank(rank))) + file += fileStep + rank += rankStep + } + return out +} + +func compareStep(a, b int) int { + switch { + case a > b: + return 1 + case a < b: + return -1 + default: + return 0 + } +} + +func abs(n int) int { + if n < 0 { + return -n + } + return n +} + +func sameDiagonal(a Square, b Square) bool { + fileDelta := int(a.File()) - int(b.File()) + if fileDelta < 0 { + fileDelta = -fileDelta + } + rankDelta := int(a.Rank()) - int(b.Rank()) + if rankDelta < 0 { + rankDelta = -rankDelta + } + return fileDelta == rankDelta +} + +func squareFromBit(bb bitboard) Square { + return Square(63 - bits.TrailingZeros64(uint64(bb))) +} + +// init populates the bbSquares lookup table. This is done at package +// initialization because the values are constants derived from square indices. +// +//nolint:gochecknoinits // Required for lookup table initialization. +func init() { + const numOfSquaresInBoard = 64 + for sq := range numOfSquaresInBoard { + bbSquares[sq] = bitboard(uint64(1) << (uint8(63) - uint8(sq))) + } + initAlignedMasks() + initRayMasks() + initMagicAttackTables() +} + +func initAlignedMasks() { + for a := range numOfSquaresInBoard { + for b := range numOfSquaresInBoard { + if squaresAligned(Square(a), Square(b)) { + alignedMasks[a] |= bbForSquare(Square(b)) + } + } + } +} + +func initRayMasks() { + for a := range numOfSquaresInBoard { + for b := range numOfSquaresInBoard { + fileStep, rankStep, diagonal := rayStep(Square(a), Square(b)) + rayFileSteps[a][b] = int8(fileStep) + rayRankSteps[a][b] = int8(rankStep) + rayDiagonals[a][b] = diagonal + betweenMasks[a][b] = squaresBetween(Square(a), Square(b)) + } + } +} diff --git a/perft.go b/perft.go new file mode 100644 index 00000000..aae28212 --- /dev/null +++ b/perft.go @@ -0,0 +1,146 @@ +package chess + +// Perft (performance test) counts the number of legal move sequences of the +// given length reachable from the receiver. It is a standard correctness and +// performance test for chess move generators. +// +// A depth of 0 counts the current position itself. A depth of 1 counts the +// number of legal moves. Otherwise each legal move is applied in turn and the +// counts are summed recursively. +// +// Perft is purely a node counter; it does not collect, store, or annotate the +// move sequences. For a per-root-move breakdown use Divide. +// +// Example: +// +// pos := chess.StartingPosition() +// nodes := pos.Perft(5) // 4 865 609 for the start position +// +// The traversal uses the same legality rules that govern normal play, but it +// applies moves through an internal make/unmake path to avoid allocating a new +// Position at each ply. A position that is checkmate or stalemate returns 0 for +// any depth greater than 0 (no legal moves to count). +func (pos *Position) Perft(depth int) uint64 { + if pos == nil { + return 0 + } + return pos.perftInPlace(depth) +} + +func (pos *Position) perftInPlace(depth int) uint64 { + if depth <= 0 { + return 1 + } + var nodes uint64 + visitLegalMoves(pos, generateLegalOnly, func(m Move) bool { + if depth == 1 { + nodes++ + return false + } + undo := pos.makeMove(m) + nodes += pos.perftInPlace(depth - 1) + pos.unmakeMove(undo) + return false + }) + return nodes +} + +// Divide returns the per-root-move Perft breakdown at the given depth: a map +// from each legal move in the current position to the number of leaf positions +// reachable in exactly depth-1 further plies after that move. It is the +// per-move form of Perft and is typically used to localize a divergence +// between two move generators. +// +// Like Perft, a depth of 0 returns a single-entry map for the current position +// (the move is the zero Move, count 1). A position with no legal moves returns +// an empty map for any depth greater than 0. +// +// The map iteration order is unspecified; sort by key if a stable display is +// required. +// +// Example: +// +// pos := chess.StartingPosition() +// results := pos.Divide(1) +// for _, m := range sortedMoves(results) { +// fmt.Printf("%s: %d\n", m, results[m]) +// } +func (pos *Position) Divide(depth int) map[Move]uint64 { + if pos == nil { + return nil + } + if depth <= 0 { + return map[Move]uint64{Move{}: 1} + } + out := make(map[Move]uint64) + visitLegalMoves(pos, generateLegalOnly, func(m Move) bool { + if depth == 1 { + out[m] = 1 + return false + } + undo := pos.makeMove(m) + out[m] = pos.perftInPlace(depth - 1) + pos.unmakeMove(undo) + return false + }) + return out +} + +type positionUndo struct { + board Board + castleRights CastleRights + validMoves []Move + halfMoveClock int + moveCount int + turn Color + enPassantSquare Square + inCheck bool + checkers bitboard + hash uint64 + status Method + statusCached bool +} + +func (pos *Position) makeMove(m Move) positionUndo { + undo := positionUndo{ + board: pos.board, + castleRights: pos.castleRights, + validMoves: pos.validMoves, + halfMoveClock: pos.halfMoveClock, + moveCount: pos.moveCount, + turn: pos.turn, + enPassantSquare: pos.enPassantSquare, + inCheck: pos.inCheck, + checkers: pos.checkers, + hash: pos.hash, + status: pos.status, + statusCached: pos.statusCached, + } + + if m.HasTag(Null) { + next := pos.nullUpdate() + *pos = *next + return undo + } + + pos.applyMove(m) + // Perft and Divide never inspect intermediate hashes. The undo record + // restores the caller-visible hash exactly after traversal, so applyMove + // leaving the hash untouched is safe here. + return undo +} + +func (pos *Position) unmakeMove(undo positionUndo) { + pos.board = undo.board + pos.castleRights = undo.castleRights + pos.validMoves = undo.validMoves + pos.halfMoveClock = undo.halfMoveClock + pos.moveCount = undo.moveCount + pos.turn = undo.turn + pos.enPassantSquare = undo.enPassantSquare + pos.inCheck = undo.inCheck + pos.checkers = undo.checkers + pos.hash = undo.hash + pos.status = undo.status + pos.statusCached = undo.statusCached +} diff --git a/perft_test.go b/perft_test.go new file mode 100644 index 00000000..c16c7070 --- /dev/null +++ b/perft_test.go @@ -0,0 +1,311 @@ +package chess_test + +import ( + "fmt" + "sort" + "testing" + + "github.com/corentings/chess/v3" +) + +func ExamplePosition_Perft() { + pos := chess.StartingPosition() + fmt.Println(pos.Perft(3)) // 8,902 leaf positions at depth 3 + // Output: 8902 +} + +// perftCase pairs a position with the expected node counts for each depth, +// from depth 1 up to the last entry. Values are from +// https://www.chessprogramming.org/Perft_Results. +type perftCase struct { + name string + fen string + nodes []uint64 // index 0 = depth 1, index i = depth (i+1) + maxDepth int // cap recursion at this depth to keep tests fast +} + +var perftCases = []perftCase{ + { + name: "startpos", + fen: "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + // depths 1..4 only; depth 5 alone is 4.8M and depth 6 is 119M + nodes: []uint64{20, 400, 8902, 197281, 4865609}, + maxDepth: 4, + }, + { + name: "kiwipete", + fen: "r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1", + nodes: []uint64{48, 2039, 97862, 4085603, 193690690}, + maxDepth: 4, + }, + { + name: "pos3", + fen: "8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1", + nodes: []uint64{14, 191, 2812, 43238, 674624, 11030083, 178633661}, + maxDepth: 6, + }, + { + name: "pos4", + fen: "r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1", + nodes: []uint64{6, 264, 9467, 422333, 15833292, 706045033}, + maxDepth: 5, + }, + { + name: "pos5", + fen: "r2q1rk1/pP1p2pp/Q4n2/bbp1p3/Np6/1B3NBn/pPPP1PPP/R3K2R b KQ - 0 1", + nodes: []uint64{6, 264, 9467, 422333, 15833292, 706045033}, + maxDepth: 5, + }, + { + name: "pos6", + fen: "rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8", + nodes: []uint64{44, 1486, 62379, 2103487, 89941194}, + maxDepth: 4, + }, +} + +func TestPerft(t *testing.T) { + for _, c := range perftCases { + t.Run(c.name, func(t *testing.T) { + opt, err := chess.FEN(c.fen) + if err != nil { + t.Fatalf("FEN decode: %v", err) + } + pos := chess.NewGame(opt).Position() + for depth, want := range c.nodes { + if depth+1 > c.maxDepth { + break + } + got := pos.Perft(depth + 1) + if got != want { + t.Errorf("depth %d: got %d, want %d", depth+1, got, want) + } + } + }) + } +} + +func TestPerftBaseCases(t *testing.T) { + t.Run("depth_zero_is_one", func(t *testing.T) { + pos := chess.NewGame().Position() + if got := pos.Perft(0); got != 1 { + t.Errorf("Perft(0) = %d, want 1", got) + } + }) + + t.Run("depth_one_equals_legal_moves", func(t *testing.T) { + pos := chess.NewGame().Position() + if got, want := pos.Perft(1), uint64(len(pos.ValidMoves())); got != want { + t.Errorf("Perft(1) = %d, want %d", got, want) + } + }) + + t.Run("terminal_position_returns_zero", func(t *testing.T) { + // Fool's mate: 1.f3 e5 2.g4 Qh4# -- black just delivered mate + opt, err := chess.FEN("rnbqkbnr/pppp1ppp/8/4p3/6Pq/5P2/PPPPP2P/RNBQKBNR w KQkq - 0 2") + if err != nil { + t.Fatalf("FEN decode: %v", err) + } + pos := chess.NewGame(opt).Position() + if got := pos.Perft(1); got != 0 { + t.Errorf("Perft(1) on checkmate position = %d, want 0", got) + } + }) + + t.Run("nil_position_is_zero", func(t *testing.T) { + var pos *chess.Position + if got := pos.Perft(3); got != 0 { + t.Errorf("Perft(3) on nil = %d, want 0", got) + } + }) +} + +func TestPerftRuleRegressions(t *testing.T) { + tests := []struct { + name string + fen string + nodes []uint64 + }{ + { + name: "castling_rights", + fen: "r3k2r/8/8/8/8/8/8/R3K2R w KQkq - 0 1", + nodes: []uint64{26, 568}, + }, + { + name: "en_passant", + fen: "rnbqkbnr/ppp1pppp/8/3pP3/8/8/PPPP1PPP/RNBQKBNR w KQkq d6 0 3", + nodes: []uint64{31, 807}, + }, + { + name: "promotion", + fen: "4k3/P7/8/8/8/8/8/4K3 w - - 0 1", + nodes: []uint64{9, 41}, + }, + { + name: "pinned_piece", + fen: "4k3/8/8/8/8/8/4R3/4K2r w - - 0 1", + nodes: []uint64{2, 8}, + }, + { + name: "single_check", + fen: "4k3/8/8/8/8/8/4r3/4K3 w - - 0 1", + nodes: []uint64{3, 41}, + }, + { + name: "double_check", + fen: "4k3/8/8/8/8/3b4/4r3/4K3 w - - 0 1", + nodes: []uint64{2, 54}, + }, + { + name: "checkmate", + fen: "rnbqkbnr/pppp1ppp/8/4p3/6Pq/5P2/PPPPP2P/RNBQKBNR w KQkq - 0 2", + nodes: []uint64{0, 0}, + }, + { + name: "stalemate", + fen: "7k/5Q2/6K1/8/8/8/8/8 b - - 0 1", + nodes: []uint64{0, 0}, + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + opt, err := chess.FEN(tt.fen) + if err != nil { + t.Fatalf("FEN decode: %v", err) + } + pos := chess.NewGame(opt).Position() + for depth, want := range tt.nodes { + if got := pos.Perft(depth + 1); got != want { + t.Errorf("Perft(%d) = %d, want %d", depth+1, got, want) + } + } + }) + } +} + +func TestDivide(t *testing.T) { + opt, err := chess.FEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1") + if err != nil { + t.Fatalf("FEN decode: %v", err) + } + pos := chess.NewGame(opt).Position() + got := pos.Divide(1) + if len(got) != 20 { + t.Fatalf("Divide(1) returned %d moves, want 20", len(got)) + } + for _, count := range got { + if count != 1 { + t.Errorf("Divide(1) per-move count = %d, want 1", count) + } + } + + // depth 1 sum must equal Perft(1) + var sum uint64 + for _, v := range got { + sum += v + } + if sum != pos.Perft(1) { + t.Errorf("sum(Divide(1)) = %d, want %d", sum, pos.Perft(1)) + } + + // depth 2: known total 400 + depth2 := pos.Divide(2) + var sum2 uint64 + for _, v := range depth2 { + sum2 += v + } + if sum2 != 400 { + t.Errorf("sum(Divide(2)) = %d, want 400", sum2) + } +} + +func TestDivideStable(t *testing.T) { + // Verify the map is well-defined (not a pointer map): two equal moves + // coming from a second call produce the same key. + pos := chess.NewGame().Position() + first := pos.Divide(1) + second := pos.Divide(1) + if len(first) != len(second) { + t.Fatalf("Divide(1) non-deterministic size: %d vs %d", len(first), len(second)) + } + keys := make([]string, 0, len(first)) + for k := range first { + keys = append(keys, k.String()) + } + sort.Strings(keys) + for i := 1; i < len(keys); i++ { + if keys[i] == keys[i-1] { + t.Errorf("Divide(1) returned duplicate move key %q", keys[i]) + } + } +} + +func TestPerftAndDivideDoNotChangePosition(t *testing.T) { + tests := []struct { + name string + fen string + }{ + { + name: "startpos", + fen: "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + }, + { + name: "castling_and_en_passant", + fen: "r3k2r/pbppqpb1/1pn3p1/7p/1N2pPn1/1PP4N/PB1P2PP/2QRKR2 b kq f3 0 1", + }, + { + name: "promotion", + fen: "4k3/P7/8/8/8/8/8/4K3 w - - 0 1", + }, + { + name: "check_giving_moves", + fen: "4k3/8/8/8/4N3/8/8/4R1K1 w - - 0 1", + }, + } + + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + pos := positionFromFEN(t, tt.fen) + beforeFEN := pos.String() + beforeMoves := moveStrings(pos.ValidMoves()) + + _ = pos.Perft(3) + if got := pos.String(); got != beforeFEN { + t.Fatalf("Perft mutated position: got %q, want %q", got, beforeFEN) + } + if got := moveStrings(pos.ValidMoves()); !equalStrings(got, beforeMoves) { + t.Fatalf("Perft changed legal moves: got %v, want %v", got, beforeMoves) + } + + _ = pos.Divide(3) + if got := pos.String(); got != beforeFEN { + t.Fatalf("Divide mutated position: got %q, want %q", got, beforeFEN) + } + if got := moveStrings(pos.ValidMoves()); !equalStrings(got, beforeMoves) { + t.Fatalf("Divide changed legal moves: got %v, want %v", got, beforeMoves) + } + }) + } +} + +func moveStrings(moves []chess.Move) []string { + out := make([]string, 0, len(moves)) + for _, move := range moves { + out = append(out, move.String()) + } + sort.Strings(out) + return out +} + +func equalStrings(a []string, b []string) bool { + if len(a) != len(b) { + return false + } + for i := range a { + if a[i] != b[i] { + return false + } + } + return true +} diff --git a/pgn.go b/pgn.go index c1624ab8..99c07a2f 100644 --- a/pgn.go +++ b/pgn.go @@ -1,67 +1,129 @@ -/* -Package chess provides PGN (Portable Game Notation) parsing functionality, -supporting standard chess notation including moves, variations, comments, -annotations, and game metadata. -Example usage: - - // Create parser from tokens - tokens := TokenizeGame(game) - parser := NewParser(tokens) - - // Parse complete game - game, err := parser.Parse() -*/ package chess import ( - "errors" "fmt" "strconv" + "strings" ) // Parser holds the state needed during parsing. type Parser struct { - game *Game - currentMove *Move - tokens []Token - errors []ParserError - position int + game *Game + tokens pgnTokenSource + lexer *Lexer + moveText MoveTextCodec + token Token + initErr error + errors []ParserError + position int + tagOutcome Outcome + tokenOutcome Outcome } -// NewParser creates a new parser instance initialized with the given tokens. -// The parser starts with a root move containing the starting position. -// -// Example: -// -// tokens := TokenizeGame(game) -// parser := NewParser(tokens) -func NewParser(tokens []Token) *Parser { - rootMove := &Move{ - position: StartingPosition(), +type pgnTokenSource interface { + NextToken() (Token, error) +} + +type sliceTokenSource struct { + tokens []Token + pos int +} + +func (s *sliceTokenSource) NextToken() (Token, error) { + if s.pos >= len(s.tokens) { + return Token{Type: EOF}, nil + } + token := s.tokens[s.pos] + s.pos++ + return token, nil +} + +// lexerTokenSource adapts a Lexer to the pgnTokenSource interface so the +// parser can consume a raw PGN movetext stream without materialising every +// token up front. +type lexerTokenSource struct { + lexer *Lexer +} + +func (s *lexerTokenSource) NextToken() (Token, error) { + return s.lexer.NextToken(), nil +} + +// parsePGNText parses raw PGN movetext into a Game using the given options. +func parsePGNText(raw string, options pgnOptions) (*Game, error) { + return newParserFromSource(&lexerTokenSource{lexer: NewLexer(raw)}, options).Parse() +} + +// newParser creates a parser from a pre-built token slice. This is the test +// seam for parser state-machine unit tests in pgn_test.go. +func newParser(tokens []Token) *Parser { + return newParserFromSource(&sliceTokenSource{tokens: tokens}, defaultPGNOptions()) +} + +func newParserFromSource(tokens pgnTokenSource, opts ...pgnOptions) *Parser { + options := defaultPGNOptions() + if len(opts) > 0 { + options = opts[0] } - return &Parser{ + pos := StartingPosition() + tree := newMoveTree(pos) + parser := &Parser{ tokens: tokens, game: &Game{ - tagPairs: make(TagPairs), - pos: StartingPosition(), - rootMove: rootMove, // Empty root move - currentMove: rootMove, + tagPairs: make(TagPairs), + tree: tree, + outcome: NoOutcome, + method: NoMethod, }, - currentMove: rootMove, + moveText: options.moveTextCodec, } + if source, ok := tokens.(*lexerTokenSource); ok { + parser.lexer = source.lexer + parser.token = parser.lexer.NextToken() + return parser + } + token, err := tokens.NextToken() + if err != nil { + parser.initErr = err + parser.token = Token{Type: Undefined, Value: err.Error()} + return parser + } + parser.token = token + return parser } // currentToken returns the current token being processed. func (p *Parser) currentToken() Token { - if p.position >= len(p.tokens) { - return Token{Type: EOF} - } - return p.tokens[p.position] + return p.token } // advance moves to the next token. +// ponytail: dual branch skips one interface call on the hot lexer path; the +// slice branch is test-only and uncovered by the unit suite (pgn_test.go:878). +// Unify on p.tokens.NextToken() — interface cost (~1-2 ns) is parse-noise. func (p *Parser) advance() { p.position++ + if p.lexer != nil { + p.token = p.lexer.NextToken() + return + } + token, err := p.tokens.NextToken() + if err != nil { + p.token = Token{Type: Undefined, Value: err.Error()} + return + } + p.token = token +} + +func (p *Parser) atEnd() bool { + return p.currentToken().Type == EOF +} + +func (p *Parser) currentMove() *MoveNode { + if p == nil || p.game == nil || p.game.tree == nil { + return nil + } + return p.game.tree.Current() } // Parse processes all tokens and returns the complete game. @@ -78,34 +140,60 @@ func (p *Parser) advance() { // } // fmt.Printf("Event: %s\n", game.GetTagPair("Event")) func (p *Parser) Parse() (*Game, error) { + if p.initErr != nil { + return nil, p.initErr + } + // Parse header section (tag pairs) if err := p.parseHeader(); err != nil { - return nil, errors.New("parsing header") + return nil, fmt.Errorf("%w: parsing header: %w", ErrInvalidPGN, err) } + p.tagOutcome = outcomeFromResultString(p.game.tagPairs["Result"]) + // check if the game has a starting position if value, ok := p.game.tagPairs["FEN"]; ok { pos, err := decodeFEN(value) if err != nil { - return nil, errors.New("invalid FEN") + return nil, fmt.Errorf("%w: %w", ErrInvalidFEN, err) + } + if variantFromTag(p.game.tagPairs["Variant"]) == Chess960 { + pos.variant = Chess960 } - p.game.rootMove.position = pos - p.game.pos = pos + p.game.tree.setRootPosition(pos) + } else if variantFromTag(p.game.tagPairs["Variant"]) == Chess960 { + // Chess960 declared without a FEN: default to the standard arrangement + // (SP-518) treated as a Chess960 position. + pos := StartingPosition() + pos.variant = Chess960 + p.game.tree.setRootPosition(pos) } // Parse moves section if err := p.parseMoveText(); err != nil { return nil, err } + // Terminal-only policy: derive checkmate/stalemate from the final main-line + // position but leave automatic draws unset, so the Result tag and movetext + // token remain authoritative; resolveOutcome then arbitrates. + p.game.outcome, p.game.method = classifyOutcome(p.game.currentPosition(), 0, outcomeRules{}) - if p.game.outcome == UnknownOutcome { - p.game.outcome = NoOutcome + if err := p.resolveOutcome(); err != nil { + return nil, err } - p.game.currentMove = p.currentMove - return p.game, nil } +func (p *Parser) resolveOutcome() error { + outcome, method, err := arbitratePGNOutcome(p.game.outcome, p.game.method, p.tagOutcome, p.tokenOutcome) + if err != nil { + return &ParserError{Message: err.Error(), Position: p.position} + } + p.game.outcome = outcome + p.game.method = method + return nil +} + func (p *Parser) parseHeader() error { for p.currentToken().Type == TagStart { if err := p.parseTagPair(); err != nil { @@ -167,16 +255,27 @@ func (p *Parser) parseTagPair() error { return nil } +// variantFromTag maps a PGN Variant tag value to a Variant. Recognised Chess960 +// aliases (case-insensitive) yield Chess960; anything else yields Standard. +func variantFromTag(s string) Variant { + switch strings.ToLower(strings.TrimSpace(s)) { + case "chess960", "chess 960", "fischer random", "fischerrandom", + "fischerandom", "frc", "960": + return Chess960 + } + return Standard +} + func (p *Parser) parseMoveText() error { var moveNumber uint64 ply := 1 - for p.position < len(p.tokens) { + for !p.atEnd() { token := p.currentToken() switch token.Type { case MoveNumber: number, err := strconv.ParseUint(token.Value, 10, 32) - if err == nil && p.currentMove != nil { + if err == nil && p.currentMove() != nil { moveNumber = number ply = int((moveNumber-1)*2 + 1) } @@ -189,36 +288,22 @@ func (p *Parser) parseMoveText() error { p.advance() ply++ + case NullMove: + p.addMove(NewNullMove(), uint(moveNumber)) + p.advance() + ply++ + case PIECE, SQUARE, FILE, KingsideCastle, QueensideCastle: move, err := p.parseMove() if err != nil { return err } - if moveNumber > 0 { - move.number = uint(moveNumber) - } - p.addMove(move) + p.addMove(move, uint(moveNumber)) ply++ // Collect all NAGs and comments that follow the move - collectLoop: - for { - tok := p.currentToken() - switch tok.Type { - case NAG: - p.currentMove.nag = tok.Value - p.advance() - case CommentStart: - block, err := p.parseComment() - if err != nil { - return err - } - if p.currentMove != nil { - p.currentMove.addCommentBlock(block) - } - default: - break collectLoop - } + if err = p.collectMoveAnnotations(); err != nil { + return err } case CommentStart: @@ -226,8 +311,8 @@ func (p *Parser) parseMoveText() error { if err != nil { return err } - if p.currentMove != nil { - p.currentMove.addCommentBlock(block) + if current := p.currentMove(); current != nil { + current.addCommentBlock(block) } case VariationStart: @@ -246,243 +331,97 @@ func (p *Parser) parseMoveText() error { return nil } -// parseMove processes tokens until it has a complete move, then validates against legal moves. -func (p *Parser) parseMove() (*Move, error) { - move := &Move{} - - // Handle castling first as it's a special case - if p.currentToken().Type == KingsideCastle { - move.tags = KingSideCastle - for _, m := range p.game.pos.ValidMovesUnsafe() { - if m.HasTag(KingSideCastle) { - move.s1 = m.S1() - move.s2 = m.S2() - if m.HasTag(Check) { - move.AddTag(Check) - } - p.advance() - return move, nil - } - } - return nil, &ParserError{ - Message: "illegal kingside castle", - TokenType: p.currentToken().Type, - TokenValue: p.currentToken().Value, - Position: p.position, - } - } - - if p.currentToken().Type == QueensideCastle { - move.tags = QueenSideCastle - for _, m := range p.game.pos.ValidMovesUnsafe() { - if m.HasTag(QueenSideCastle) { - move.s1 = m.S1() - move.s2 = m.S2() - move.position = p.game.pos - if m.HasTag(Check) { - move.AddTag(Check) - } - p.advance() - return move, nil - } - } - return nil, &ParserError{ - Message: "illegal queenside castle", - TokenType: p.currentToken().Type, - TokenValue: p.currentToken().Value, - Position: p.position, - } +func (p *Parser) parseMove() (Move, error) { + data := sanMoveData{ + piece: Pawn, + canonical: p.moveText.Policy() == MoveTextPolicyStrict, } - // Parse regular move - var moveData struct { - piece string // The piece type (if any) - originFile string // Disambiguation file - originRank string // Disambiguation rank - destSquare string // Destination square - isCapture bool // Whether it's a capture - promotion PieceType // Promotion piece type - } - - // First token could be piece, file (for pawn moves), or square - switch p.currentToken().Type { - case PIECE: - moveData.piece = p.currentToken().Value + // Castling: single token + if p.currentToken().Type == KingsideCastle || p.currentToken().Type == QueensideCastle { + data.castle = p.currentToken().Value p.advance() + } else { + // Regular move: piece? disambiguation? capture? square promotion? check? + hasPiece := p.currentToken().Type == PIECE + if hasPiece { + data.piece = algebraicPieceType(p.currentToken().Value) + p.advance() + } - // Check for disambiguation - if p.currentToken().Type == FILE { - moveData.originFile = p.currentToken().Value + // Optional disambiguation (file, rank, or full origin square) + switch p.currentToken().Type { + case FILE: + data.originFile = p.currentToken().Value p.advance() - } else if p.currentToken().Type == RANK { - moveData.originRank = p.currentToken().Value + case RANK: + data.originRank = p.currentToken().Value p.advance() - } else if p.currentToken().Type == DeambiguationSquare { - // Full square disambiguation (e.g., "Qe8f7" -> piece: Q, origin: e8, dest: f7) - originSquare := p.currentToken().Value - if len(originSquare) == 2 { - moveData.originFile = string(originSquare[0]) - moveData.originRank = string(originSquare[1]) + case DeambiguationSquare: + if value := p.currentToken().Value; len(value) == 2 { + data.originFile = value[:1] + data.originRank = value[1:] } p.advance() } - case FILE: - moveData.originFile = p.currentToken().Value - p.advance() - - } - - // Handle capture - if p.currentToken().Type == CAPTURE { - moveData.isCapture = true - p.advance() - } - - // Get destination square - if p.currentToken().Type != SQUARE { - return nil, &ParserError{ - Message: "expected destination square", - TokenType: p.currentToken().Type, - TokenValue: p.currentToken().Value, - Position: p.position, + // Optional capture + if p.currentToken().Type == CAPTURE { + data.capture = true + p.advance() } - } - moveData.destSquare = p.currentToken().Value - p.advance() - // Handle promotion - if p.currentToken().Type == PROMOTION { - p.advance() - if p.currentToken().Type != PromotionPiece { - return nil, &ParserError{ - Message: "expected promotion piece", + // Required destination square + if p.currentToken().Type != SQUARE || len(p.currentToken().Value) != 2 { + return Move{}, &ParserError{ + Message: "expected destination square", TokenType: p.currentToken().Type, TokenValue: p.currentToken().Value, Position: p.position, } } - moveData.promotion = parsePieceType(p.currentToken().Value) + destSquare := p.currentToken().Value + data.dest = squareFromFileRank(destSquare[0], destSquare[1]) p.advance() - } - // Get target square - targetSquare := parseSquare(moveData.destSquare) - if targetSquare == NoSquare { - return nil, &ParserError{ - Message: "invalid destination square", - TokenType: p.currentToken().Type, - TokenValue: p.currentToken().Value, - Position: p.position, - } - } - - // Find matching legal move - var matchingMove *Move - var err error - validMoves := p.game.pos.ValidMovesUnsafe() - for _, m := range validMoves { - //nolint:nestif // readability - if m.S2() == targetSquare { - pos := p.game.pos - piece := pos.Board().Piece(m.S1()) - - // Check piece type - if moveData.piece != "" && piece.Type() != PieceTypeFromString(moveData.piece) || moveData.piece == "" && piece.Type() != Pawn { - err = &ParserError{ - Message: "piece type mismatch", - TokenType: p.currentToken().Type, - TokenValue: p.currentToken().Value, - Position: p.position, - } - continue - } - - // Check disambiguation - if moveData.originFile != "" && m.S1().File().String() != moveData.originFile { - err = &ParserError{ - Message: "origin file mismatch", - TokenType: p.currentToken().Type, - TokenValue: p.currentToken().Value, - Position: p.position, - } - continue - } - if moveData.originRank != "" && strconv.Itoa(int((m.S1()/8)+1)) != moveData.originRank { - err = &ParserError{ - Message: fmt.Sprintf("origin rank mismatch: %d", m.S1()/8+1), - TokenType: p.currentToken().Type, - TokenValue: p.currentToken().Value, - Position: p.position, - } - continue - } - - // Check capture - if moveData.isCapture != (m.HasTag(Capture) || m.HasTag(EnPassant)) { - err = &ParserError{ - Message: "capture mismatch", - TokenType: p.currentToken().Type, - TokenValue: p.currentToken().Value, - Position: p.position, - } - continue - } - - // Check promotion - if moveData.promotion != NoPieceType && m.promo != moveData.promotion { - err = &ParserError{ - Message: "promotion mismatch", + // Promotion with "=" + if p.currentToken().Type == PROMOTION { + p.advance() + if p.currentToken().Type != PromotionPiece { + return Move{}, &ParserError{ + Message: "expected promotion piece", TokenType: p.currentToken().Type, TokenValue: p.currentToken().Value, Position: p.position, } - continue } - - matchingMove = &m - break - } - } - - if matchingMove == nil { - if err != nil { - return nil, &ParserError{ - Message: fmt.Sprintf("no legal move found for position: %s", err.Error()), - Position: p.position, + data.promotion = algebraicPieceType(p.currentToken().Value) + p.advance() + } else if p.moveText.Policy() == MoveTextPolicyPGNImport && + !hasPiece && + p.currentToken().Type == PIECE && + (destSquare[1] == '1' || destSquare[1] == '8') { + // Import-only promotion without "=" (e.g., e8Q). + v := p.currentToken().Value + if v == "Q" || v == "R" || v == "B" || v == "N" { + data.promotion = algebraicPieceType(v) + p.advance() } } - return nil, &ParserError{ - Message: "no legal move found for position", - Position: p.position, - } - } - - // Copy the matched move details - move.s1 = matchingMove.S1() - move.s2 = matchingMove.S2() - move.tags = matchingMove.tags - move.promo = matchingMove.promo - - // Handle check/checkmate if present - if p.currentToken().Type == CHECK { - move.tags |= Check - p.advance() } - // Handle NAG if present - if p.currentToken().Type == NAG { - move.nag = p.currentToken().Value + // Optional check/checkmate suffix + if p.currentToken().Type == CHECK || p.currentToken().Type == CHECKMATE { p.advance() } - // Set move number for both white and black moves - if p.game.pos != nil && p.game.pos.Turn() == Black { - if parentMoveNum := p.currentMove.number; parentMoveNum > 0 { - move.number = parentMoveNum + move, err := resolveSANMove(p.game.currentPosition(), data) + if err != nil { + return Move{}, &ParserError{ + Message: strings.TrimPrefix(ErrInvalidMoveText.Error()+": "+err.Error(), "chess: "), + Position: p.position, } } - return move, nil } @@ -491,7 +430,7 @@ func (p *Parser) parseComment() (CommentBlock, error) { block := CommentBlock{} - for p.currentToken().Type != CommentEnd && p.position < len(p.tokens) { + for p.currentToken().Type != CommentEnd && !p.atEnd() { switch p.currentToken().Type { case CommandStart: command, err := p.parseCommand() @@ -513,7 +452,7 @@ func (p *Parser) parseComment() (CommentBlock, error) { p.advance() } - if p.position >= len(p.tokens) { + if p.atEnd() { return CommentBlock{}, &ParserError{ Message: "unterminated comment", Position: p.position, @@ -531,10 +470,17 @@ func (p *Parser) parseCommand() (CommentItem, error) { // Consume the opening "[" p.advance() - for p.currentToken().Type != CommandEnd && p.position < len(p.tokens) { + for p.currentToken().Type != CommandEnd && !p.atEnd() { switch p.currentToken().Type { - case CommandName: + if key != "" { + return CommentItem{}, &ParserError{ + Message: "duplicate command name in command", + Position: p.position, + TokenType: p.currentToken().Type, + TokenValue: p.currentToken().Value, + } + } // The first token in a command is treated as the key key = p.currentToken().Value case CommandParam: @@ -553,46 +499,74 @@ func (p *Parser) parseCommand() (CommentItem, error) { p.advance() } - if p.position >= len(p.tokens) { + if p.atEnd() { return CommentItem{}, &ParserError{ Message: "unterminated command", Position: p.position, } } - // p.advance() // Consume the closing "]" return CommentItem{Kind: CommentCommand, Key: key, Value: value}, nil } +// collectMoveAnnotations consumes all NAGs and comments immediately following +// the current move, attaching them to the current move node. +func (p *Parser) collectMoveAnnotations() error { + for { + tok := p.currentToken() + switch tok.Type { + case NAG: + if nagErr := p.currentMove().AddNAG(tok.Value); nagErr != nil { + return &ParserError{ + Message: nagErr.Error(), + TokenValue: tok.Value, + TokenType: NAG, + Position: p.position, + } + } + p.advance() + case CommentStart: + block, err := p.parseComment() + if err != nil { + return err + } + if current := p.currentMove(); current != nil { + current.addCommentBlock(block) + } + default: + return nil + } + } +} + func (p *Parser) parseVariation(parentMoveNumber uint64, parentPly int) error { p.advance() // consume ( // Save current state to restore later - parentMove := p.currentMove - oldPos := p.game.pos + parentMove := p.currentMove() + oldCurrent := p.game.tree.Current() + + // Restore the active cursor when this function returns, including on + // every err path between here and the end. Previously the restore was + // open-coded at the success branch only, leaking the cursor into the + // abandoned variation subtree on any error. + defer p.game.tree.setCurrent(oldCurrent) // For variations at game start, we attach to root - variationParent := p.game.rootMove + variationParent := p.game.tree.Root() - // Find the move this variation should branch from - if parentMove != p.game.rootMove && parentMove.parent != nil { + // Find the move this variation should diverge from + if parentMove != p.game.tree.Root() && parentMove.parent != nil { variationParent = parentMove.parent - if variationParent.parent != nil && variationParent.parent.position != nil { - p.game.pos = variationParent.parent.position.Update(variationParent) - } else { - p.game.pos = p.game.rootMove.position.copy() - } - } else { - p.game.pos = p.game.rootMove.position.copy() } - p.currentMove = variationParent + p.game.tree.setCurrent(variationParent) moveNumber := parentMoveNumber ply := parentPly isBlackMove := false - for p.currentToken().Type != VariationEnd && p.position < len(p.tokens) { + for p.currentToken().Type != VariationEnd && !p.atEnd() { switch p.currentToken().Type { case MoveNumber: num, err := strconv.ParseUint(p.currentToken().Value, 10, 32) @@ -611,6 +585,12 @@ func (p *Parser) parseVariation(parentMoveNumber uint64, parentPly int) error { isBlackMove = true ply++ + case NullMove: + p.addMove(NewNullMove(), uint(moveNumber)) + p.advance() + ply++ + isBlackMove = !isBlackMove + case VariationStart: if err := p.parseVariation(moveNumber, ply); err != nil { return err @@ -621,16 +601,23 @@ func (p *Parser) parseVariation(parentMoveNumber uint64, parentPly int) error { if err != nil { return err } - if p.currentMove != nil { - p.currentMove.addCommentBlock(block) + if current := p.currentMove(); current != nil { + current.addCommentBlock(block) } case NAG: - p.currentMove.nag = p.currentToken().Value + if nagErr := p.currentMove().AddNAG(p.currentToken().Value); nagErr != nil { + return &ParserError{ + Message: nagErr.Error(), + TokenValue: p.currentToken().Value, + TokenType: NAG, + Position: p.position, + } + } p.advance() case PIECE, SQUARE, FILE, KingsideCastle, QueensideCastle: - if isBlackMove != (p.game.pos.Turn() == Black) { + if isBlackMove != (p.game.currentPosition().Turn() == Black) { return &ParserError{ Message: "move color mismatch", Position: p.position, @@ -642,36 +629,13 @@ func (p *Parser) parseVariation(parentMoveNumber uint64, parentPly int) error { return err } - move.parent = p.currentMove - p.currentMove.children = append(p.currentMove.children, move) - move.number = uint(moveNumber) - - p.game.pos = p.game.pos.Update(move) - - move.position = p.game.pos - p.currentMove = move + p.addMove(move, uint(moveNumber)) ply++ isBlackMove = !isBlackMove // Collect all NAGs and comments that follow the move - collectVariationAnnotations: - for { - tok := p.currentToken() - switch tok.Type { - case NAG: - p.currentMove.nag = tok.Value - p.advance() - case CommentStart: - block, err := p.parseComment() - if err != nil { - return err - } - if p.currentMove != nil { - p.currentMove.addCommentBlock(block) - } - default: - break collectVariationAnnotations - } + if err = p.collectMoveAnnotations(); err != nil { + return err } default: @@ -679,7 +643,7 @@ func (p *Parser) parseVariation(parentMoveNumber uint64, parentPly int) error { } } - if p.position >= len(p.tokens) { + if p.atEnd() { return &ParserError{ Message: "unterminated variation", Position: p.position, @@ -688,85 +652,22 @@ func (p *Parser) parseVariation(parentMoveNumber uint64, parentPly int) error { p.advance() // consume ) - p.game.pos = oldPos - p.currentMove = parentMove - p.game.currentMove = p.currentMove - return nil } func (p *Parser) parseResult() { - result := p.currentToken().Value - switch result { - case "1-0": - p.game.outcome = WhiteWon - case "0-1": - p.game.outcome = BlackWon - case "1/2-1/2": - p.game.outcome = Draw - default: - p.game.outcome = NoOutcome - } + p.tokenOutcome = outcomeFromResultString(p.currentToken().Value) p.advance() } -func (p *Parser) addMove(move *Move) { - // For the first move in the game - if p.currentMove == p.game.rootMove { - move.parent = p.game.rootMove - p.game.rootMove.children = append(p.game.rootMove.children, move) - } else { - // Normal move in the main line - move.parent = p.currentMove - p.currentMove.children = append(p.currentMove.children, move) - } - - // Update position - if newPos := p.game.pos.Update(move); newPos != nil { - p.game.pos = newPos - p.game.evaluatePositionStatus() - } - - // Cache position after the move - move.position = p.game.pos - - p.currentMove = move -} - -// parsePieceType converts a piece character into a PieceType. -func parsePieceType(s string) PieceType { - switch s { - case "P": - return Pawn - case "N": - return Knight - case "B": - return Bishop - case "R": - return Rook - case "Q": - return Queen - case "K": - return King - default: - return NoPieceType - } +func outcomeFromResultString(s string) Outcome { + o, _ := ParseOutcome(s) + return o } -// parseSquare converts a square name (e.g., "e4") into a Square. -func parseSquare(s string) Square { - const squareLen = 2 - if len(s) != squareLen { - return NoSquare - } - - file := int(s[0] - 'a') - rank := int(s[1] - '1') - - // Validate file and rank are within bounds - if file < 0 || file > 7 || rank < 0 || rank > 7 { - return NoSquare - } - - return Square(rank*8 + file) +func (p *Parser) addMove(move Move, number uint) { + parent := p.currentMove() + node := &MoveNode{move: move, parent: parent, tree: p.game.tree, number: number} + parent.children = append(parent.children, node) + p.game.tree.setCurrent(node) } diff --git a/pgn_alloc_budget_test.go b/pgn_alloc_budget_test.go new file mode 100644 index 00000000..6bfef55d --- /dev/null +++ b/pgn_alloc_budget_test.go @@ -0,0 +1,54 @@ +package chess + +import ( + "bytes" + "errors" + "io" + "testing" +) + +// Alloc-budget ratchet: ceilings sit ~5% above the post-ticket-06 baseline. +// Baseline observed (AllocsPerRun, 10 iterations): +// - big.pgn: ~544,000 allocs/run +// - big_big.pgn: ~1,925,000 allocs/run +// +// Compared to the pre-cursor baseline (~690k / ~2.86M) this is a 21-33% +// reduction from dropping per-node *Position and per-MoveList position +// caches; positions are now resolved lazily via the MoveTree cursor. +// Lower as fixes land; never raise without confirming the alloc growth is real. +const ( + pgnAllocBudgetBigBig = 2_050_000 + pgnAllocBudgetBig = 575_000 +) + +func TestPGNDecode_AllocBudget_BigBig(t *testing.T) { + assertPGNAllocBudget(t, "big_big.pgn", pgnAllocBudgetBigBig) +} + +func TestPGNDecode_AllocBudget_Big(t *testing.T) { + assertPGNAllocBudget(t, "big.pgn", pgnAllocBudgetBig) +} + +func assertPGNAllocBudget(t *testing.T, fixture string, budget float64) { + t.Helper() + data := readPGNFixture(fixture) + allocs := testing.AllocsPerRun(10, func() { + dec := NewPGNDecoder(bytes.NewReader(data)) + for { + g, err := dec.Decode() + if errors.Is(err, io.EOF) { + return + } + if err != nil { + if isKnownInconsistentPgn(err) { + continue + } + t.Fatalf("decode error: %v", err) + } + _ = g.Outcome() + } + }) + if allocs > budget { + t.Fatalf("decode %s: %.0f allocs/run, budget %.0f", fixture, allocs, budget) + } +} diff --git a/pgn_decoder.go b/pgn_decoder.go new file mode 100644 index 00000000..3bc7c69e --- /dev/null +++ b/pgn_decoder.go @@ -0,0 +1,461 @@ +package chess + +import ( + "context" + "errors" + "fmt" + "io" + "iter" + "runtime" + "strings" + "sync" +) + +// PGNOption configures PGN decoding. +type PGNOption func(*pgnOptions) + +type pgnOptions struct { + bufferSize int + expandVariations bool + moveTextCodec MoveTextCodec +} + +// WithPGNExpandVariations expands each Game's Variations into separate Games. +func WithPGNExpandVariations() PGNOption { + return func(o *pgnOptions) { + o.expandVariations = true + } +} + +// WithPGNBufferSize configures the reader buffer size used for PGN record framing. +func WithPGNBufferSize(n int) PGNOption { + return func(o *pgnOptions) { + if n > 0 { + o.bufferSize = n + } + } +} + +// WithStrictSAN requires PGN movetext to use strict canonical SAN. +func WithStrictSAN() PGNOption { + return func(o *pgnOptions) { + o.moveTextCodec = SAN() + } +} + +// WithImportSAN accepts documented PGN import SAN spellings. +func WithImportSAN() PGNOption { + return func(o *pgnOptions) { + o.moveTextCodec = PGNImportSAN() + } +} + +// PGNDecoder streams Games from a PGN reader. +type PGNDecoder struct { + framer *pgnFramer + options []PGNOption + parsedGames []*Game + index int64 + offset int64 +} + +// NewPGNDecoder creates a decoder that reads Games from r. +func NewPGNDecoder(r io.Reader, opts ...PGNOption) *PGNDecoder { + return &PGNDecoder{framer: newPGNFramer(r, opts...), options: opts} +} + +// Decode returns the next Game from the PGN stream. +func (d *PGNDecoder) Decode() (*Game, error) { + if len(d.parsedGames) > 0 { + game := d.parsedGames[0] + d.parsedGames = d.parsedGames[1:] + d.index++ + return game, nil + } + + record, err := d.framer.next() + if err != nil { + return nil, err + } + d.index++ + d.offset = record.Offset + + options := applyPGNOptions(d.options) + + game, err := parsePGNText(record.Raw, options) + if err != nil { + return nil, fmt.Errorf("%w: %w", ErrInvalidPGN, err) + } + + if options.expandVariations { + games := game.Split() + if len(games) == 0 { + return nil, io.EOF + } + d.parsedGames = games[1:] + game = games[0] + } + + return game, nil +} + +// Index returns the number of Games successfully decoded by this decoder. +func (d *PGNDecoder) Index() int64 { + return d.index +} + +// Offset returns the byte offset of the current PGN record when available. +func (d *PGNDecoder) Offset() int64 { + return d.offset +} + +// ParsePGN parses the first Game from r. Any returned error wraps +// ErrInvalidPGN so callers can errors.Is(err, ErrInvalidPGN) without +// inspecting message text; io.EOF is returned unchanged when r yields no game. +func ParsePGN(r io.Reader, opts ...PGNOption) (*Game, error) { + return NewPGNDecoder(r, opts...).Decode() +} + +// PGNGames returns an iterator over Games decoded from r. +func PGNGames(r io.Reader, opts ...PGNOption) iter.Seq2[*Game, error] { + return func(yield func(*Game, error) bool) { + dec := NewPGNDecoder(r, opts...) + for { + game, err := dec.Decode() + if errors.Is(err, io.EOF) { + return + } + if !yield(game, err) || err != nil { + return + } + } + } +} + +// PGNRecord is one complete PGN game record from a stream. +type PGNRecord struct { + Index int64 + Offset int64 + Raw string +} + +// Decode parses this record into a Game. +func (r PGNRecord) Decode(opts ...PGNOption) (*Game, error) { + return parsePGNText(r.Raw, applyPGNOptions(opts)) +} + +// Tags returns the PGN tag pairs in this record without building a Game. +func (r PGNRecord) Tags() (map[string]string, error) { + lex := NewLexer(r.Raw) + tags := make(map[string]string) + for { + tok := lex.NextToken() + if tok.Type == EOF || tok.Type != TagStart { + return tags, nil + } + key := lex.NextToken() + val := lex.NextToken() + end := lex.NextToken() + if end.Type == TagEnd && key.Type == TagKey && val.Type == TagValue { + tags[key.Value] = val.Value + } + } +} + +// PGNRecords returns an iterator over raw PGN records. +func PGNRecords(ctx context.Context, r io.Reader, opts ...PGNOption) iter.Seq2[PGNRecord, error] { + return func(yield func(PGNRecord, error) bool) { + framer := newPGNFramer(r, opts...) + for { + if err := ctx.Err(); err != nil { + yield(PGNRecord{}, err) + return + } + + record, err := framer.next() + if errors.Is(err, io.EOF) { + return + } + if !yield(record, err) || err != nil { + return + } + } + } +} + +// PGNParallelOptions configures parallel PGN Game decoding. +type PGNParallelOptions struct { + Workers int + Buffer int + Ordered bool + Options []PGNOption +} + +// PGNResult is the result of decoding one PGN record. +type PGNResult struct { + Game *Game + Err error + Index int64 + Offset int64 +} + +// DecodePGNGamesParallel decodes PGN records across worker goroutines. +func DecodePGNGamesParallel(ctx context.Context, r io.Reader, opts PGNParallelOptions) <-chan PGNResult { + if opts.Workers <= 0 { + opts.Workers = runtime.GOMAXPROCS(0) + } + if opts.Buffer <= 0 { + opts.Buffer = opts.Workers + } + + out := make(chan PGNResult, opts.Buffer) + jobs := make(chan PGNRecord, opts.Buffer) + results := make(chan PGNResult, opts.Buffer) + + go func() { + defer close(jobs) + for record, err := range PGNRecords(ctx, r, opts.Options...) { + if err != nil { + results <- PGNResult{Err: err} + return + } + select { + case jobs <- record: + case <-ctx.Done(): + results <- PGNResult{Err: ctx.Err()} + return + } + } + }() + + var wg sync.WaitGroup + wg.Add(opts.Workers) + for range opts.Workers { + go func() { + defer wg.Done() + for record := range jobs { + game, err := record.Decode(opts.Options...) + result := PGNResult{Game: game, Err: err, Index: record.Index, Offset: record.Offset} + select { + case results <- result: + case <-ctx.Done(): + return + } + } + }() + } + + go func() { + wg.Wait() + close(results) + }() + + go func() { + defer close(out) + if opts.Ordered { + yieldOrderedPGNResults(ctx, out, results) + return + } + for result := range results { + if !sendPGNResult(ctx, out, result) { + return + } + } + }() + + return out +} + +func sendPGNResult(ctx context.Context, out chan<- PGNResult, result PGNResult) bool { + select { + case out <- result: + return true + case <-ctx.Done(): + select { + case out <- PGNResult{Err: ctx.Err()}: + default: + } + return false + } +} + +func yieldOrderedPGNResults(ctx context.Context, out chan<- PGNResult, results <-chan PGNResult) { + // Index zero or negative results (typically record-stream errors from + // the framer goroutine) are emitted immediately without ordering. + // Workers may still be decoding in-flight records when an error arrives; + // their results will be dropped because the results channel closes after + // this function returns. + next := int64(1) + pending := make(map[int64]PGNResult) + for result := range results { + if result.Index <= 0 { + if !sendPGNResult(ctx, out, result) { + return + } + continue + } + pending[result.Index] = result + for { + ready, ok := pending[next] + if !ok { + break + } + delete(pending, next) + if !sendPGNResult(ctx, out, ready) { + return + } + next++ + } + } +} + +// PGNEventKind identifies a semantic PGN event. +type PGNEventKind uint8 + +const ( + PGNEventUnknown PGNEventKind = iota + PGNTag + PGNMove + PGNComment + PGNNAG + PGNVariationStart + PGNVariationEnd + PGNGameEnd +) + +// PGNEvent is one semantic event from a PGN stream. +type PGNEvent struct { + Kind PGNEventKind + Index int64 + Offset int64 + Name string + Value string + Move string + NAG string +} + +// PGNEvents returns an iterator over semantic PGN events without building Games. +func PGNEvents(r io.Reader, opts ...PGNOption) iter.Seq2[PGNEvent, error] { + return func(yield func(PGNEvent, error) bool) { + for record, err := range PGNRecords(context.Background(), r, opts...) { + if err != nil { + yield(PGNEvent{}, err) + return + } + if !yieldPGNRecordEvents(record, yield) { + return + } + } + } +} + +func yieldPGNRecordEvents(record PGNRecord, yield func(PGNEvent, error) bool) bool { + lex := NewLexer(record.Raw) + var pending *Token + for { + var tok Token + if pending != nil { + tok = *pending + pending = nil + } else { + tok = lex.NextToken() + } + if tok.Type == EOF { + return yield(PGNEvent{Kind: PGNGameEnd, Index: record.Index, Offset: record.Offset}, nil) + } + event := PGNEvent{Index: record.Index, Offset: record.Offset} + switch tok.Type { + case TagStart: + key := lex.NextToken() + val := lex.NextToken() + lex.NextToken() // TagEnd + if key.Type == TagKey && val.Type == TagValue { + event.Kind = PGNTag + event.Name = key.Value + event.Value = val.Value + if !yield(event, nil) { + return false + } + } + case CommentStart: + comment := collectPGNComment(lex) + if comment != "" { + event.Kind = PGNComment + event.Value = comment + if !yield(event, nil) { + return false + } + } + case NAG: + event.Kind = PGNNAG + event.NAG = tok.Value + if !yield(event, nil) { + return false + } + case VariationStart: + event.Kind = PGNVariationStart + if !yield(event, nil) { + return false + } + case VariationEnd: + event.Kind = PGNVariationEnd + if !yield(event, nil) { + return false + } + default: + if isPGNMoveToken(tok.Type) { + move, terminator := collectPGNMove(lex, tok) + event.Kind = PGNMove + event.Move = move + if !yield(event, nil) { + return false + } + pending = &terminator + } + } + } +} + +func collectPGNComment(lex *Lexer) string { + var b strings.Builder + lastWasComment := false + for { + tok := lex.NextToken() + switch tok.Type { + case COMMENT: + b.WriteString(tok.Value) + lastWasComment = true + case CommandStart: + if lastWasComment && b.Len() > 0 { + b.WriteByte(' ') + } + lastWasComment = false + case CommentEnd: + return b.String() + case EOF: + return b.String() + } + } +} + +func collectPGNMove(lex *Lexer, first Token) (string, Token) { + var b strings.Builder + b.WriteString(first.Value) + for { + tok := lex.NextToken() + if !isPGNMoveToken(tok.Type) { + return b.String(), tok + } + b.WriteString(tok.Value) + } +} + +func isPGNMoveToken(tokenType TokenType) bool { + switch tokenType { + case PIECE, SQUARE, CAPTURE, FILE, RANK, KingsideCastle, QueensideCastle, + PROMOTION, PromotionPiece, CHECK, CHECKMATE, DeambiguationSquare, NullMove: + return true + default: + return false + } +} diff --git a/pgn_decoder_test.go b/pgn_decoder_test.go new file mode 100644 index 00000000..c9828d76 --- /dev/null +++ b/pgn_decoder_test.go @@ -0,0 +1,125 @@ +package chess_test + +import ( + "errors" + "io" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +const decoderGameOne = `[Event "one"] +[Site "?"] +[Date "2026.06.28"] +[Round "?"] +[White "White"] +[Black "Black"] +[Result "*"] + +1. e4 * +` + +const decoderGameTwo = `[Event "two"] +[Site "?"] +[Date "2026.06.28"] +[Round "?"] +[White "White"] +[Black "Black"] +[Result "*"] + +1. d4 * +` + +func TestParsePGNReturnsSingleGame(t *testing.T) { + game, err := chess.ParsePGN(strings.NewReader(decoderGameOne)) + if err != nil { + t.Fatalf("ParsePGN error: %v", err) + } + if got := game.GetTagPair("Event"); got != "one" { + t.Fatalf("Event tag = %q, want %q", got, "one") + } + if got := len(game.Moves()); got != 1 { + t.Fatalf("len(Moves) = %d, want 1", got) + } +} + +func TestPGNDecoderDecodesMultipleGames(t *testing.T) { + dec := chess.NewPGNDecoder(strings.NewReader(decoderGameOne + "\n" + decoderGameTwo)) + + first, err := dec.Decode() + if err != nil { + t.Fatalf("first Decode error: %v", err) + } + if got := first.GetTagPair("Event"); got != "one" { + t.Fatalf("first Event tag = %q, want %q", got, "one") + } + if dec.Index() != 1 { + t.Fatalf("Index after first Decode = %d, want 1", dec.Index()) + } + + second, err := dec.Decode() + if err != nil { + t.Fatalf("second Decode error: %v", err) + } + if got := second.GetTagPair("Event"); got != "two" { + t.Fatalf("second Event tag = %q, want %q", got, "two") + } + if dec.Index() != 2 { + t.Fatalf("Index after second Decode = %d, want 2", dec.Index()) + } + + if _, err := dec.Decode(); !errors.Is(err, io.EOF) { + t.Fatalf("final Decode error = %v, want io.EOF", err) + } +} + +func TestPGNGamesIteratesGamesAndErrors(t *testing.T) { + var events []string + for game, err := range chess.PGNGames(strings.NewReader(decoderGameOne + "\n" + decoderGameTwo)) { + if err != nil { + t.Fatalf("PGNGames yielded error: %v", err) + } + events = append(events, game.GetTagPair("Event")) + } + + if strings.Join(events, ",") != "one,two" { + t.Fatalf("events = %v, want [one two]", events) + } +} + +func TestPGNDecoderEmptyInputReturnsEOF(t *testing.T) { + dec := chess.NewPGNDecoder(strings.NewReader(" \n\t")) + if _, err := dec.Decode(); !errors.Is(err, io.EOF) { + t.Fatalf("Decode error = %v, want io.EOF", err) + } +} + +func TestPGNDecoderExpandsVariations(t *testing.T) { + pgn := `[Event "variations"] +[Site "?"] +[Date "2026.06.28"] +[Round "?"] +[White "White"] +[Black "Black"] +[Result "*"] + +1. e4 (1. d4) * +` + dec := chess.NewPGNDecoder(strings.NewReader(pgn), chess.WithPGNExpandVariations()) + + first, err := dec.Decode() + if err != nil { + t.Fatalf("first Decode error: %v", err) + } + second, err := dec.Decode() + if err != nil { + t.Fatalf("second Decode error: %v", err) + } + if _, err := dec.Decode(); !errors.Is(err, io.EOF) { + t.Fatalf("final Decode error = %v, want io.EOF", err) + } + if len(first.Moves()) != 1 || len(second.Moves()) != 1 { + t.Fatalf("expanded games should each have one move, got %d and %d", len(first.Moves()), len(second.Moves())) + } +} diff --git a/pgn_disambiguation_test.go b/pgn_disambiguation_test.go index 06581031..3c097687 100644 --- a/pgn_disambiguation_test.go +++ b/pgn_disambiguation_test.go @@ -1,153 +1,112 @@ -package chess +package chess_test import ( "strings" "testing" -) -// Test cases for PGN disambiguation parsing issue #73 -// The issue is that moves like "Qe8f7" (queen from e8 to f7) fail to parse -// because the parser doesn't handle full square disambiguation properly. + "github.com/corentings/chess/v3" +) -func TestPGNDisambiguationSquares(t *testing.T) { +func TestPGN_ParsesDisambiguationGame(t *testing.T) { tests := []struct { - name string - pgn string - shouldFail bool - description string + name string + pgn string + shouldFail bool }{ { - name: "multiple_pieces_same_type_complex", - pgn: `1. h4 d6 2. g4 Kd7 3. f4 Kc6 4. f5 Kd7 5. g5 Ke8 6. h5 Kd7 7. h6 Kc6 8. g6 Kb6 9. f6 Kc6 10. hxg7 Kd7 11. gxf7 Kc6 12. fxe7 Kb6 13. gxf8=Q Kc6 14. fxg8=Q Kb6 15. e8=Q Ka6 16. Qfe7 Kb6 17. Qe8f7`, - shouldFail: false, - description: "Complex game without full square disambiguation (should work)", + name: "multiple_pieces_same_type_complex", + pgn: `1. h4 d6 2. g4 Kd7 3. f4 Kc6 4. f5 Kd7 5. g5 Ke8 6. h5 Kd7 7. h6 Kc6 8. g6 Kb6 9. f6 Kc6 10. hxg7 Kd7 11. gxf7 Kc6 12. fxe7 Kb6 13. gxf8=Q Kc6 14. fxg8=Q Kb6 15. e8=Q Ka6 16. Qfe7 Kb6 17. Qe8f7`, + shouldFail: false, }, } for _, tc := range tests { t.Run(tc.name, func(t *testing.T) { - reader := strings.NewReader(tc.pgn) - scanner := NewScanner(reader) - - game, err := scanner.ParseNext() + game, err := chess.ParsePGN(strings.NewReader(tc.pgn)) if err != nil { if !tc.shouldFail { - t.Errorf("Expected PGN parsing to succeed but got error: %v", err) - } - // If we expected it to fail, verify it's the right kind of error - if tc.shouldFail && !strings.Contains(err.Error(), "invalid destination square") { - t.Logf("Expected 'invalid destination square' error but got: %v", err) + t.Errorf("%s: expected PGN parsing to succeed but got error: %v", tc.name, err) } return } - if tc.shouldFail { - t.Errorf("Expected test case '%s' to fail but it succeeded. Description: %s", tc.name, tc.description) + t.Errorf("%s: expected test case to fail but it succeeded", tc.name) } - - // Additional validation for successful cases - if !tc.shouldFail { - if game == nil { - t.Errorf("Game should not be nil for successful parsing") - } + if game == nil { + t.Errorf("%s: game should not be nil for successful parsing", tc.name) } }) } } -// TestTokenizerDisambiguationSquares tests that the lexer correctly tokenizes disambiguation squares -func TestTokenizerDisambiguationSquares(t *testing.T) { +func TestLexer_FullSquareDisambiguation(t *testing.T) { tests := []struct { name string input string - expected []TokenType + expected []chess.Token }{ - { - name: "queen_with_full_square_disambiguation", - input: "Qe8f7", - expected: []TokenType{PIECE, DeambiguationSquare, SQUARE}, - }, - { - name: "rook_with_full_square_disambiguation", - input: "Ra1d1", - expected: []TokenType{PIECE, DeambiguationSquare, SQUARE}, - }, - { - name: "knight_with_full_square_disambiguation", - input: "Nb1c3", - expected: []TokenType{PIECE, DeambiguationSquare, SQUARE}, - }, - { - name: "queen_with_full_square_disambiguation_capture", - input: "Qg8xg7", - expected: []TokenType{PIECE, DeambiguationSquare, CAPTURE, SQUARE}, - }, - { - name: "rook_with_full_square_disambiguation_capture", - input: "Ra1xa8", - expected: []TokenType{PIECE, DeambiguationSquare, CAPTURE, SQUARE}, - }, - { - name: "knight_with_full_square_disambiguation_capture", - input: "Nb1xc3", - expected: []TokenType{PIECE, DeambiguationSquare, CAPTURE, SQUARE}, - }, - { - name: "standard_piece_move", - input: "Nf3", - expected: []TokenType{PIECE, SQUARE}, - }, - { - name: "piece_with_file_disambiguation", - input: "Nbd2", - expected: []TokenType{PIECE, FILE, SQUARE}, - }, - { - name: "piece_with_rank_disambiguation", - input: "R1d2", - expected: []TokenType{PIECE, RANK, SQUARE}, - }, + {"queen_full_square", "Qe8f7", []chess.Token{ + {Type: chess.PIECE, Value: "Q"}, + {Type: chess.DeambiguationSquare, Value: "e8"}, + {Type: chess.SQUARE, Value: "f7"}, + }}, + {"rook_full_square", "Ra1d1", []chess.Token{ + {Type: chess.PIECE, Value: "R"}, + {Type: chess.DeambiguationSquare, Value: "a1"}, + {Type: chess.SQUARE, Value: "d1"}, + }}, + {"knight_full_square", "Nb1c3", []chess.Token{ + {Type: chess.PIECE, Value: "N"}, + {Type: chess.DeambiguationSquare, Value: "b1"}, + {Type: chess.SQUARE, Value: "c3"}, + }}, + {"queen_full_square_capture", "Qg8xg7", []chess.Token{ + {Type: chess.PIECE, Value: "Q"}, + {Type: chess.DeambiguationSquare, Value: "g8"}, + {Type: chess.CAPTURE, Value: "x"}, + {Type: chess.SQUARE, Value: "g7"}, + }}, + {"standard_piece_move", "Nf3", []chess.Token{ + {Type: chess.PIECE, Value: "N"}, + {Type: chess.SQUARE, Value: "f3"}, + }}, + {"file_disambiguation", "Nbd2", []chess.Token{ + {Type: chess.PIECE, Value: "N"}, + {Type: chess.FILE, Value: "b"}, + {Type: chess.SQUARE, Value: "d2"}, + }}, + {"rank_disambiguation", "R1d2", []chess.Token{ + {Type: chess.PIECE, Value: "R"}, + {Type: chess.RANK, Value: "1"}, + {Type: chess.SQUARE, Value: "d2"}, + }}, } for _, tc := range tests { t.Run(tc.name, func(t *testing.T) { - lexer := NewLexer(tc.input) - var actualTypes []TokenType - - for { + lexer := chess.NewLexer(tc.input) + for i, expected := range tc.expected { token := lexer.NextToken() - if token.Type == EOF { - break + if token.Type != expected.Type || token.Value != expected.Value { + t.Errorf("Token %d: expected {%v, %q}, got {%v, %q}", + i, expected.Type, expected.Value, token.Type, token.Value) } - actualTypes = append(actualTypes, token.Type) - t.Logf("Token: %s, Value: %s", token.Type, token.Value) - } - - if len(actualTypes) != len(tc.expected) { - t.Errorf("Expected %d tokens, got %d", len(tc.expected), len(actualTypes)) - t.Errorf("Expected: %v", tc.expected) - t.Errorf("Actual: %v", actualTypes) - return } - - for i, expected := range tc.expected { - if actualTypes[i] != expected { - t.Errorf("Token %d: expected %s, got %s", i, expected, actualTypes[i]) - } + if tok := lexer.NextToken(); tok.Type != chess.EOF { + t.Errorf("expected EOF after tokens, got {%v, %q}", tok.Type, tok.Value) } }) } } -func TestPGNFullSquareDisambiguationCapture(t *testing.T) { +func TestPGN_ParsesFullSquareCapture(t *testing.T) { pgn := `[Event "rated blitz game"] [Site "https://lichess.org/FaQvH6Iq"] [Result "1-0"] 1. c4 Nf6 2. Nc3 Ng8 3. e4 Nf6 4. e5 Ng8 5. d4 e6 6. f4 Ne7 7. Nf3 Ng8 8. d5 Ne7 9. Be3 Nf5 10. Bf2 Ne7 11. Bd3 Ng8 12. O-O Nh6 13. h3 Ng8 14. g4 h5 15. g5 d6 16. Qc2 Qf6 17. exf6 Nc6 18. fxg7 Bd7 19. gxh8=Q O-O-O 20. g6 Bg7 21. gxf7 Kb8 22. fxg8=Q Ka8 23. f5 Rf8 24. f6 Be8 25. f7 Nd8 26. fxe8=Q Kb8 27. Qhxh5 Ka8 28. Qg4 Kb8 29. h4 Ka8 30. h5 Kb8 31. h6 Ka8 32. h7 Kb8 33. h8=Q Ka8 34. dxe6 Kb8 35. e7 Ka8 36. exf8=Q Kb8 37. Qg8xg7 Ka8 38. Qgg8 Kb8 39. Q4g7 Ka8 40. c5 Kb8 41. cxd6 Ka8 42. dxc7 b6 43. cxd8=Q# 1-0` - scanner := NewScanner(strings.NewReader(pgn)) - game, err := scanner.ParseNext() + game, err := chess.ParsePGN(strings.NewReader(pgn)) if err != nil { t.Fatalf("expected PGN with full-square disambiguation capture to parse: %v", err) } @@ -155,18 +114,58 @@ func TestPGNFullSquareDisambiguationCapture(t *testing.T) { t.Fatal("expected game to be parsed") } - // Verify the specific problematic move (Qg8xg7) was parsed correctly. - // Move 37 is at index 72 (0-based) in the moves slice. moves := game.Moves() if len(moves) < 73 { t.Fatalf("expected at least 73 moves, got %d", len(moves)) } move37 := moves[72] - if move37.String() != "g8g7" { - t.Errorf("expected move 37 to be g8g7, got %s", move37.String()) + if move37.S1() != chess.G8 || move37.S2() != chess.G7 { + t.Errorf("expected move 37 to be g8g7, got %s%s", move37.S1(), move37.S2()) } - if !move37.HasTag(Capture) { + if !move37.HasTag(chess.Capture) { t.Errorf("expected move 37 to have Capture tag") } } + +func TestAlgebraicNotation_EncodeDisambiguation(t *testing.T) { + tests := []struct { + name string + fen string + from, to chess.Square + wantSAN string + }{ + {"none", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", chess.E2, chess.E4, "e4"}, + {"file_only", "rnbqkbnr/pppp1ppp/8/4p3/3P4/5N2/PPP1PPPP/RNBQKB1R w KQkq - 0 1", chess.F3, chess.D2, "Nfd2"}, + {"rank_only", "4k3/8/8/8/R7/8/8/R3K3 w - - 0 1", chess.A4, chess.A3, "R4a3"}, + {"file_and_rank", "1k6/8/8/8/Q7/8/8/Q2QK3 w - - 0 1", chess.A1, chess.D4, "Qa1d4"}, + } + for _, tc := range tests { + t.Run(tc.name, func(t *testing.T) { + opt, err := chess.FEN(tc.fen) + if err != nil { + t.Fatalf("%s: invalid FEN: %v", tc.name, err) + } + pos := chess.NewGame(opt).Position() + var target chess.Move + found := false + for _, m := range pos.ValidMoves() { + if m.S1() == tc.from && m.S2() == tc.to { + target = m + found = true + break + } + } + if !found { + t.Skipf("%s: move %s%s unavailable in position", tc.name, tc.from, tc.to) + } + got, err := chess.SAN().Encode(pos, target) + if err != nil { + t.Fatalf("%s: Encode error: %v", tc.name, err) + } + if got != tc.wantSAN { + t.Errorf("%s: Encode = %q, want %q", tc.name, got, tc.wantSAN) + } + }) + } +} diff --git a/pgn_edge_cases_test.go b/pgn_edge_cases_test.go new file mode 100644 index 00000000..8afc97c3 --- /dev/null +++ b/pgn_edge_cases_test.go @@ -0,0 +1,239 @@ +package chess_test + +import ( + "errors" + "io" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +func TestPGNDecoderPreservesEscapedQuoteInTagValue(t *testing.T) { + const escapedQuoteGame = `[Event "Internet Section 08A g/8'+2\""] +[Site "Dos Hermanas"] +[Date "2004.03.08"] +[Round "6"] +[White "Di Berardino, Diego Rafael"] +[Black "Mar, Fernando"] +[Result "1/2-1/2"] +[ECO "B96"] + +1. e4 c5 2. Nf3 1/2-1/2 +` + dec := chess.NewPGNDecoder(strings.NewReader(escapedQuoteGame)) + game, err := dec.Decode() + if err != nil { + t.Fatalf("parser rejects spec-legal escaped quote in tag value: %v", err) + } + if game.GetTagPair("Event") != `Internet Section 08A g/8'+2"` { + t.Fatalf("expected unescaped quote in tag value, got %q", game.GetTagPair("Event")) + } + pgn := game.String() + if !strings.Contains(pgn, `[Event "Internet Section 08A g/8'+2\""]`) { + t.Fatalf("round-trip PGN does not contain escaped quote: %s", pgn) + } +} + +func TestPGNImportAcceptsPromotionWithoutEquals(t *testing.T) { + const pgn = `[Event "Promotion import"] +[SetUp "1"] +[FEN "6k1/4P3/8/8/8/8/8/4K3 w - - 0 1"] +[Result "*"] + +1. e8Q * +` + + game, err := chess.ParsePGN(strings.NewReader(pgn)) + if err != nil { + t.Fatalf("ParsePGN rejected import promotion without equals: %v", err) + } + if got := game.String(); !strings.Contains(got, "1. e8=Q") { + t.Fatalf("generated PGN should canonicalise promotion with equals, got:\n%s", got) + } +} + +func TestPGNSANPolicyOptionsLastOneWins(t *testing.T) { + const pgn = `[Event "Promotion import"] +[SetUp "1"] +[FEN "6k1/4P3/8/8/8/8/8/4K3 w - - 0 1"] +[Result "*"] + +1. e8Q * +` + + if _, err := chess.ParsePGN(strings.NewReader(pgn), chess.WithStrictSAN()); err == nil { + t.Fatalf("ParsePGN WithStrictSAN accepted import-only promotion spelling") + } + if _, err := chess.ParsePGN(strings.NewReader(pgn), chess.WithStrictSAN(), chess.WithImportSAN()); err != nil { + t.Fatalf("ParsePGN last import option error = %v", err) + } + if _, err := chess.ParsePGN(strings.NewReader(pgn), chess.WithImportSAN(), chess.WithStrictSAN()); err == nil { + t.Fatalf("ParsePGN last strict option accepted import-only promotion spelling") + } +} + +func TestPGNDecoderGameBoundaries(t *testing.T) { + tests := []struct { + name string + input string + wantGames int + wantOutcome chess.Outcome + }{ + {"empty", "", 0, chess.NoOutcome}, + {"whitespace_only", " \n\t ", 0, chess.NoOutcome}, + {"result_only", "1-0\n", 1, chess.WhiteWon}, + {"star_result_only_not_detected", "*\n", 0, chess.NoOutcome}, + {"tagless_game", "1. e4 e5 1-0\n", 1, chess.WhiteWon}, + {"tags_only", "[Event \"x\"]\n[Site \"y\"]\n\n", 1, chess.NoOutcome}, + {"crlf_no_tag_separator", "1. e4 e5 1-0\r\n1. d4 d5 0-1\r\n", 1, chess.WhiteWon}, + {"bom_prefix", "\xEF\xBB\xBF1. e4 e5 1-0\n", 0, chess.NoOutcome}, + {"no_blank_line_separator", "1. e4 e5 1-0\n[Event \"z\"]\n\n1. d4 d5 0-1\n", 1, chess.BlackWon}, + {"trailing_garbage", "1. e4 e5 1-0\nGARBAGE\n", 1, chess.WhiteWon}, + {"result_prefix_no_false_positive", "10-0\n", 1, chess.NoOutcome}, + {"result_embedded_in_movetext", "1-0e5\n", 1, chess.NoOutcome}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + dec := chess.NewPGNDecoder(strings.NewReader(tt.input)) + count := 0 + var lastOutcome chess.Outcome + for { + g, err := dec.Decode() + if errors.Is(err, io.EOF) { + break + } + if err != nil { + t.Fatalf("unexpected error: %v", err) + } + lastOutcome = g.Outcome() + count++ + } + if count != tt.wantGames { + t.Errorf("game count = %d, want %d", count, tt.wantGames) + } + if tt.wantGames > 0 && lastOutcome != tt.wantOutcome { + t.Errorf("outcome = %s, want %s", lastOutcome, tt.wantOutcome) + } + }) + } +} + +func TestPGNDecoderRoundTrip(t *testing.T) { + pgn := mustReadFile("fixtures/pgns/variations.pgn") + dec := chess.NewPGNDecoder(strings.NewReader(pgn)) + for { + g, err := dec.Decode() + if errors.Is(err, io.EOF) { + break + } + if err != nil { + t.Fatalf("parse error: %v", err) + } + rendered := g.String() + reparsed := mustParseSingleGame(t, rendered) + if reparsed.String() != rendered { + t.Errorf("round-trip mismatch:\nfirst:\n%s\nsecond:\n%s", rendered, reparsed.String()) + } + } +} + +func TestPGNDecoderVariationExpansionFixtures(t *testing.T) { + tests := []struct { + name string + fixture string + expandVariations bool + lastLines []string + finalPos []string + }{ + {"variations_expand", "fixtures/pgns/variations.pgn", true, + []string{ + "1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Nxd4 *", + "1. e4 e5 2. Nc3 Nf6 3. f4 *", + "1. e4 d6 2. d4 Nf6 3. Nc3 e5 4. dxe5 dxe5 5. Qxd8+ Kxd8 *", + "1. e4 d6 2. d4 Nf6 3. Nc3 e5 4. Nf3 Nbd7 *", + "1. e3 e5 *", + }, + []string{ + "r1bqkbnr/pppp1ppp/2n5/8/3NP3/8/PPP2PPP/RNBQKB1R b KQkq - 0 4", + "rnbqkb1r/pppp1ppp/5n2/4p3/4PP2/2N5/PPPP2PP/R1BQKBNR b KQkq - 0 3", + "rnbk1b1r/ppp2ppp/5n2/4p3/4P3/2N5/PPP2PPP/R1B1KBNR w KQ - 0 6", + "r1bqkb1r/pppn1ppp/3p1n2/4p3/3PP3/2N2N2/PPP2PPP/R1BQKB1R w KQkq - 2 5", + "rnbqkbnr/pppp1ppp/8/4p3/8/4P3/PPPP1PPP/RNBQKBNR w KQkq - 0 2", + }}, + {"variations_no_expand", "fixtures/pgns/variations.pgn", false, + []string{ + "1. e4 (1. e3 e5) 1... e5 (1... d6 2. d4 Nf6 3. Nc3 e5 4. dxe5 (4. Nf3 Nbd7) 4... dxe5 5. Qxd8+ Kxd8) 2. Nf3 (2. Nc3 Nf6 3. f4) 2... Nc6 3. d4 exd4 4. Nxd4 1-0", + }, + []string{ + "r1bqkbnr/pppp1ppp/2n5/8/3NP3/8/PPP2PPP/RNBQKB1R b KQkq - 0 4", + }}, + {"multi_frompos_no_expand", "fixtures/pgns/multi_frompos_games.pgn", false, + []string{ + "1. d4 d5 2. c4 c6 { [%eval 0.21]} *", + "3. Nf3 (3. Nc3 Nf6 4. Nf3) 3... Nf6 4. Nc3 { [%eval 0.16]} *", + "4... a6 { [%eval 0.19]} *", + "5. cxd5 (5. e3 e6 6. cxd5 cxd5) 5... cxd5 6. e3 e6 { [%eval 0.11]} *", + }, + []string{ + "rnbqkbnr/pp2pppp/2p5/3p4/2PP4/8/PP2PPPP/RNBQKBNR w KQkq - 0 3", + "rnbqkb1r/pp2pppp/2p2n2/3p4/2PP4/2N2N2/PP2PPPP/R1BQKB1R b KQkq - 3 4", + "rnbqkb1r/1p2pppp/p1p2n2/3p4/2PP4/2N2N2/PP2PPPP/R1BQKB1R w KQkq - 0 5", + "rnbqkb1r/1p3ppp/p3pn2/3p4/3P4/2N1PN2/PP3PPP/R1BQKB1R w KQkq - 0 7", + }}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + pgn := mustReadFile(tt.fixture) + var dec *chess.PGNDecoder + if tt.expandVariations { + dec = chess.NewPGNDecoder(strings.NewReader(pgn), chess.WithPGNExpandVariations()) + } else { + dec = chess.NewPGNDecoder(strings.NewReader(pgn)) + } + count := 0 + for { + game, err := dec.Decode() + if errors.Is(err, io.EOF) { + break + } + if err != nil { + t.Fatalf("fail to parse game %d: %s", count+1, err.Error()) + } + if game == nil { + t.Fatalf("game is nil") + } + if count >= len(tt.lastLines) { + t.Fatalf("expected %d games but found at least %d", len(tt.lastLines), count+1) + } + lines := strings.Split(game.String(), "\n") + lastLine := lines[len(lines)-1] + if lastLine != tt.lastLines[count] { + t.Errorf("game output not correct\n\tExpected:'%v'\n\tGot: '%v'\n", tt.lastLines[count], lastLine) + } + fen := game.Position().XFENString() + if fen != tt.finalPos[count] { + t.Errorf("game position not correct\n\tExpected:'%v'\n\tGot: '%v'\n", tt.finalPos[count], fen) + } + count++ + } + if count != len(tt.lastLines) { + t.Fatalf("expected %d games but found only %d", len(tt.lastLines), count) + } + }) + } +} + +func TestPGNGamesReadsMultiGameFixture(t *testing.T) { + pgn := mustReadFile("fixtures/pgns/multi_game.pgn") + var games int + for _, err := range chess.PGNGames(strings.NewReader(pgn)) { + if err != nil { + t.Fatalf("unexpected error on game %d: %v", games+1, err) + } + games++ + } + if games != 4 { + t.Errorf("expected 4 games, got %d", games) + } +} diff --git a/pgn_events_test.go b/pgn_events_test.go new file mode 100644 index 00000000..ca8ed346 --- /dev/null +++ b/pgn_events_test.go @@ -0,0 +1,113 @@ +package chess_test + +import ( + "context" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +func TestPGNEventsStreamsTagsMovesCommentsAndGameEnd(t *testing.T) { + pgn := `[Event "events"] +[Site "somewhere"] +[Result "*"] + +1. e4 {hello [%clk 0:01:00]} $1 (1. d4) * +` + + var kinds []chess.PGNEventKind + var tagEvent chess.PGNEvent + var commentEvent chess.PGNEvent + var nagEvent chess.PGNEvent + var moveValues []string + + for event, err := range chess.PGNEvents(strings.NewReader(pgn)) { + if err != nil { + t.Fatalf("PGNEvents error: %v", err) + } + kinds = append(kinds, event.Kind) + switch event.Kind { + case chess.PGNTag: + if event.Name == "Event" { + tagEvent = event + } + case chess.PGNMove: + moveValues = append(moveValues, event.Move) + case chess.PGNComment: + commentEvent = event + case chess.PGNNAG: + nagEvent = event + } + } + + if tagEvent.Value != "events" { + t.Fatalf("Event tag value = %q, want events", tagEvent.Value) + } + if commentEvent.Value != "hello " { + t.Fatalf("comment value = %q, want hello with trailing space", commentEvent.Value) + } + if nagEvent.NAG != "$1" { + t.Fatalf("NAG = %q, want $1", nagEvent.NAG) + } + if strings.Join(moveValues, ",") != "e4,d4" { + t.Fatalf("moves = %v, want [e4 d4]", moveValues) + } + if len(kinds) == 0 || kinds[len(kinds)-1] != chess.PGNGameEnd { + t.Fatalf("last event kind = %v, want PGNGameEnd", kinds) + } +} + +func TestPGNEventsStreamsMultipleGamesWithIndexes(t *testing.T) { + var endIndexes []int64 + for event, err := range chess.PGNEvents(strings.NewReader(decoderGameOne + "\n" + decoderGameTwo)) { + if err != nil { + t.Fatalf("PGNEvents error: %v", err) + } + if event.Kind == chess.PGNGameEnd { + endIndexes = append(endIndexes, event.Index) + } + } + if len(endIndexes) != 2 || endIndexes[0] != 1 || endIndexes[1] != 2 { + t.Fatalf("game end indexes = %v, want [1 2]", endIndexes) + } +} + +func TestPGNRecordTagsExtractsTagsWithoutDecodingGame(t *testing.T) { + var record chess.PGNRecord + for r, err := range chess.PGNRecords(context.Background(), strings.NewReader(decoderGameOne)) { + if err != nil { + t.Fatalf("PGNRecords error: %v", err) + } + record = r + } + + tags, err := record.Tags() + if err != nil { + t.Fatalf("Tags error: %v", err) + } + if tags["Event"] != "one" { + t.Fatalf("Event tag = %q, want one", tags["Event"]) + } + if _, ok := tags["White"]; !ok { + t.Fatal("White tag missing") + } +} + +func TestPGNRecordTagsOnTruncatedTag(t *testing.T) { + var record chess.PGNRecord + for r, err := range chess.PGNRecords(context.Background(), strings.NewReader(`[Event "x"`)) { + if err != nil { + t.Fatalf("PGNRecords error: %v", err) + } + record = r + } + + tags, err := record.Tags() + if err != nil { + t.Fatalf("Tags error: %v", err) + } + if len(tags) != 0 { + t.Fatalf("tags = %v, want empty map", tags) + } +} diff --git a/pgn_frame_benchmark_test.go b/pgn_frame_benchmark_test.go new file mode 100644 index 00000000..1e020001 --- /dev/null +++ b/pgn_frame_benchmark_test.go @@ -0,0 +1,116 @@ +package chess + +import ( + "bytes" + "context" + "strings" + "testing" +) + +func BenchmarkPGN_Frame_Big(b *testing.B) { + data := readPGNFixture("big.pgn") + meta := pgnMeta("big.pgn") + b.SetBytes(meta.size) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + games := 0 + for _, err := range PGNRecords(context.Background(), bytes.NewReader(data)) { + if err != nil { + b.Fatalf("frame error: %v", err) + } + games++ + } + if games != meta.games { + b.Fatalf("expected %d games, framed %d", meta.games, games) + } + } +} + +func BenchmarkPGN_FrameSingleLargeGame(b *testing.B) { + data := []byte("[Event \"Large\"]\n\n1. " + strings.Repeat("e4 e5 ", 30_000) + "*\n") + for _, size := range []struct { + name string + bufferSize int + }{ + {"Buffer1KiB", 1024}, + {"Buffer32KiB", 32 * 1024}, + {"Buffer256KiB", 256 * 1024}, + } { + b.Run(size.name, func(b *testing.B) { + b.SetBytes(int64(len(data))) + b.ReportAllocs() + b.ResetTimer() + for range b.N { + games := 0 + for _, err := range PGNRecords(context.Background(), bytes.NewReader(data), WithPGNBufferSize(size.bufferSize)) { + if err != nil { + b.Fatalf("frame error: %v", err) + } + games++ + } + if games != 1 { + b.Fatalf("expected one game, framed %d", games) + } + } + }) + } +} + +func BenchmarkPGNRecord_Tags_Big(b *testing.B) { + data := readPGNFixture("big.pgn") + meta := pgnMeta("big.pgn") + b.SetBytes(meta.size) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + for record, err := range PGNRecords(context.Background(), bytes.NewReader(data)) { + if err != nil { + b.Fatalf("record error: %v", err) + } + if _, err := record.Tags(); err != nil { + b.Fatalf("Tags error: %v", err) + } + } + } +} + +func BenchmarkPGNEvents_Big(b *testing.B) { + data := readPGNFixture("big.pgn") + meta := pgnMeta("big.pgn") + b.SetBytes(meta.size) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + for _, err := range PGNEvents(bytes.NewReader(data)) { + if err != nil { + b.Fatalf("event error: %v", err) + } + } + } +} + +func BenchmarkPGNRecord_TagsThenDecode_Big(b *testing.B) { + data := readPGNFixture("big.pgn") + meta := pgnMeta("big.pgn") + b.SetBytes(meta.size) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + for record, err := range PGNRecords(context.Background(), bytes.NewReader(data)) { + if err != nil { + b.Fatalf("record error: %v", err) + } + if _, err := record.Tags(); err != nil { + b.Fatalf("Tags error: %v", err) + } + if _, err := record.Decode(); err != nil { + b.Fatalf("Decode error: %v", err) + } + } + } +} diff --git a/pgn_full_game_benchmark_test.go b/pgn_full_game_benchmark_test.go new file mode 100644 index 00000000..ffb96e78 --- /dev/null +++ b/pgn_full_game_benchmark_test.go @@ -0,0 +1,172 @@ +package chess + +import ( + "bytes" + "context" + "errors" + "io" + "runtime" + "testing" +) + +type pgnDecodeSummary struct { + games int + errors int + moves int + tags int + comments int + variations int + withOutcome int +} + +var pgnDecodeSummarySink pgnDecodeSummary + +func BenchmarkPGN_FullGameDecode_BigBig(b *testing.B) { + benchFullGameDecodeFixture(b, "big_big.pgn") +} + +func BenchmarkPGN_FullGameDecode_Big(b *testing.B) { + benchFullGameDecodeFixture(b, "big.pgn") +} + +func BenchmarkPGN_FullGameDecode_Parallel_BigBig(b *testing.B) { + data := readPGNFixture("big_big.pgn") + meta := pgnMeta("big_big.pgn") + workers := runtime.GOMAXPROCS(0) + b.SetBytes(meta.size) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + var summary pgnDecodeSummary + results := DecodePGNGamesParallel(context.Background(), bytes.NewReader(data), PGNParallelOptions{ + Workers: workers, + Buffer: workers * 2, + }) + for result := range results { + if result.Err != nil { + if isKnownInconsistentPgn(result.Err) { + summary.errors++ + continue + } + b.Fatalf("parallel decode error: %v", result.Err) + } + accumulatePGNDecodeSummary(&summary, result.Game) + } + if summary.games+summary.errors != meta.games { + b.Fatalf("expected %d games total, parsed %d with %d errors", meta.games, summary.games, summary.errors) + } + pgnDecodeSummarySink = summary + } +} + +func BenchmarkPGN_FullGameDecode_ExpandVariations(b *testing.B) { + data := []byte(`[Event "Variation Benchmark"] +[Site "Internet"] +[Date "2023.12.06"] +[Round "1"] +[White "Player1"] +[Black "Player2"] +[Result "1-0"] + +1. e4 e5 2. Nf3 Nc6 3. Bb5 (3. Bc4 Nf6 4. d3) a6 4. Ba4 Nf6 5. O-O Be7 1-0`) + + b.SetBytes(int64(len(data))) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + var summary pgnDecodeSummary + dec := NewPGNDecoder(bytes.NewReader(data), WithPGNExpandVariations()) + for { + game, err := dec.Decode() + if errors.Is(err, io.EOF) { + break + } + if err != nil { + b.Fatalf("decode error: %v", err) + } + accumulatePGNDecodeSummary(&summary, game) + } + pgnDecodeSummarySink = summary + } +} + +func BenchmarkPGN_FullGameDecode_CompleteGameDetails(b *testing.B) { + data := readPGNFixture("complete_game.pgn") + b.SetBytes(int64(len(data))) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + game, err := NewPGNDecoder(bytes.NewReader(data)).Decode() + if err != nil { + b.Fatalf("decode error: %v", err) + } + var summary pgnDecodeSummary + accumulatePGNDecodeSummary(&summary, game) + pgnDecodeSummarySink = summary + } +} + +func benchFullGameDecodeFixture(b *testing.B, name string) { + b.Helper() + data := readPGNFixture(name) + meta := pgnMeta(name) + b.SetBytes(meta.size) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + var summary pgnDecodeSummary + dec := NewPGNDecoder(bytes.NewReader(data)) + for { + game, err := dec.Decode() + if errors.Is(err, io.EOF) { + break + } + if err != nil { + if isKnownInconsistentPgn(err) { + summary.errors++ + continue + } + b.Fatalf("decode error: %v", err) + } + accumulatePGNDecodeSummary(&summary, game) + } + if summary.games+summary.errors != meta.games { + b.Fatalf("expected %d games total, parsed %d with %d errors", meta.games, summary.games, summary.errors) + } + pgnDecodeSummarySink = summary + } +} + +func accumulatePGNDecodeSummary(summary *pgnDecodeSummary, game *Game) { + if game == nil { + return + } + summary.games++ + summary.tags += len(game.tagPairs) + if game.Outcome() != NoOutcome { + summary.withOutcome++ + } + accumulateMoveTreeSummary(summary, game.MoveTree().Root()) +} + +func accumulateMoveTreeSummary(summary *pgnDecodeSummary, node *MoveNode) { + if node == nil { + return + } + if node.parent != nil { + summary.moves++ + } + if len(node.children) > 1 { + summary.variations += len(node.children) - 1 + } + for _, block := range node.commentBlocks { + summary.comments += len(block.Items) + } + for _, child := range node.children { + accumulateMoveTreeSummary(summary, child) + } +} diff --git a/pgn_parallel_test.go b/pgn_parallel_test.go new file mode 100644 index 00000000..f02eeaad --- /dev/null +++ b/pgn_parallel_test.go @@ -0,0 +1,101 @@ +package chess_test + +import ( + "context" + "errors" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +func TestDecodePGNGamesParallelDecodesAllGames(t *testing.T) { + ctx := context.Background() + results := chess.DecodePGNGamesParallel(ctx, strings.NewReader(decoderGameOne+"\n"+decoderGameTwo), chess.PGNParallelOptions{ + Workers: 2, + Buffer: 1, + }) + + events := map[string]bool{} + for result := range results { + if result.Err != nil { + t.Fatalf("parallel result error: %v", result.Err) + } + events[result.Game.GetTagPair("Event")] = true + } + if !events["one"] || !events["two"] || len(events) != 2 { + t.Fatalf("decoded events = %v, want one and two", events) + } +} + +func TestDecodePGNGamesParallelOrderedPreservesPGNOrder(t *testing.T) { + ctx := context.Background() + results := chess.DecodePGNGamesParallel(ctx, strings.NewReader(decoderGameOne+"\n"+decoderGameTwo), chess.PGNParallelOptions{ + Workers: 2, + Buffer: 2, + Ordered: true, + }) + + var events []string + var indexes []int64 + for result := range results { + if result.Err != nil { + t.Fatalf("parallel result error: %v", result.Err) + } + events = append(events, result.Game.GetTagPair("Event")) + indexes = append(indexes, result.Index) + } + if strings.Join(events, ",") != "one,two" { + t.Fatalf("events = %v, want [one two]", events) + } + if len(indexes) != 2 || indexes[0] != 1 || indexes[1] != 2 { + t.Fatalf("indexes = %v, want [1 2]", indexes) + } +} + +func TestDecodePGNGamesParallelReportsPerGameErrors(t *testing.T) { + bad := `[Event "bad"] +[Result "*"] + +1. NotAMove * +` + ctx := context.Background() + results := chess.DecodePGNGamesParallel(ctx, strings.NewReader(decoderGameOne+"\n"+bad+"\n"+decoderGameTwo), chess.PGNParallelOptions{ + Workers: 2, + Buffer: 2, + Ordered: true, + }) + + var good int + var failed []int64 + for result := range results { + if result.Err != nil { + failed = append(failed, result.Index) + continue + } + good++ + } + if good != 2 { + t.Fatalf("good result count = %d, want 2", good) + } + if len(failed) != 1 || failed[0] != 2 { + t.Fatalf("failed indexes = %v, want [2]", failed) + } +} + +func TestDecodePGNGamesParallelHonorsCanceledContext(t *testing.T) { + ctx, cancel := context.WithCancel(context.Background()) + cancel() + + results := chess.DecodePGNGamesParallel(ctx, strings.NewReader(decoderGameOne), chess.PGNParallelOptions{Workers: 1, Buffer: 1}) + result, ok := <-results + if !ok { + t.Fatal("result channel closed without cancellation result") + } + if !errors.Is(result.Err, context.Canceled) { + t.Fatalf("result error = %v, want context.Canceled", result.Err) + } + if _, ok := <-results; ok { + t.Fatal("result channel should close after cancellation") + } +} diff --git a/pgn_records_test.go b/pgn_records_test.go new file mode 100644 index 00000000..6aa0432a --- /dev/null +++ b/pgn_records_test.go @@ -0,0 +1,102 @@ +package chess_test + +import ( + "context" + "errors" + "io" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +func TestPGNRecordsStreamsRecordsWithIndexAndOffset(t *testing.T) { + pgn := "\n\n" + decoderGameOne + "\n" + decoderGameTwo + var records []chess.PGNRecord + + for record, err := range chess.PGNRecords(context.Background(), strings.NewReader(pgn)) { + if err != nil { + t.Fatalf("PGNRecords error: %v", err) + } + records = append(records, record) + } + + if len(records) != 2 { + t.Fatalf("len(records) = %d, want 2", len(records)) + } + if records[0].Index != 1 || records[1].Index != 2 { + t.Fatalf("record indexes = %d,%d want 1,2", records[0].Index, records[1].Index) + } + if records[0].Offset != 2 { + t.Fatalf("first offset = %d, want 2", records[0].Offset) + } + if !strings.Contains(records[0].Raw, `[Event "one"]`) { + t.Fatalf("first record raw does not contain first game: %q", records[0].Raw) + } +} + +func TestPGNRecordDecodeReturnsGame(t *testing.T) { + var record chess.PGNRecord + for r, err := range chess.PGNRecords(context.Background(), strings.NewReader(decoderGameOne)) { + if err != nil { + t.Fatalf("PGNRecords error: %v", err) + } + record = r + } + + game, err := record.Decode() + if err != nil { + t.Fatalf("Decode error: %v", err) + } + if got := game.GetTagPair("Event"); got != "one" { + t.Fatalf("Event tag = %q, want one", got) + } +} + +func TestPGNRecordsHandlesLargeRecord(t *testing.T) { + largeComment := strings.Repeat("a", 128*1024) + pgn := strings.Replace(decoderGameOne, "1. e4 *", "1. e4 {"+largeComment+"} *", 1) + + count := 0 + for record, err := range chess.PGNRecords(context.Background(), strings.NewReader(pgn)) { + if err != nil { + t.Fatalf("PGNRecords error: %v", err) + } + count++ + if len(record.Raw) < 128*1024 { + t.Fatalf("record Raw len = %d, want at least %d", len(record.Raw), 128*1024) + } + } + if count != 1 { + t.Fatalf("record count = %d, want 1", count) + } +} + +func TestPGNRecordsHonorsCanceledContext(t *testing.T) { + ctx, cancel := context.WithCancel(context.Background()) + cancel() + + for _, err := range chess.PGNRecords(ctx, strings.NewReader(decoderGameOne)) { + if !errors.Is(err, context.Canceled) { + t.Fatalf("PGNRecords error = %v, want context.Canceled", err) + } + return + } + t.Fatal("PGNRecords did not yield context cancellation") +} + +func TestPGNDecoderUsesRecordOffsets(t *testing.T) { + dec := chess.NewPGNDecoder(strings.NewReader("\n\n" + decoderGameOne)) + if _, err := dec.Decode(); err != nil { + t.Fatalf("Decode error: %v", err) + } + if dec.Index() != 1 { + t.Fatalf("Index = %d, want 1", dec.Index()) + } + if dec.Offset() != 2 { + t.Fatalf("Offset = %d, want 2", dec.Offset()) + } + if _, err := dec.Decode(); !errors.Is(err, io.EOF) { + t.Fatalf("final Decode error = %v, want io.EOF", err) + } +} diff --git a/pgn_renderer.go b/pgn_renderer.go new file mode 100644 index 00000000..40b8633c --- /dev/null +++ b/pgn_renderer.go @@ -0,0 +1,385 @@ +package chess + +import ( + "io" + "slices" + "strconv" + "strings" +) + +// PGNRenderer renders a Game into PGN text. It is a stateless +// function object that reads Game state and writes formatted PGN +// to a string or io.Writer without mutating the Game. +// +// The renderer takes a pointer so callers may extend it in the +// future (custom tag ordering, value escaping toggles, optional +// result token, etc.). All such configuration fields are deferred +// to v3.1; this initial type is a pure extraction with no knobs. +type PGNRenderer struct{} + +// DefaultPGNRenderer is the package-level renderer used by +// Game.String and Game.WritePGN. +var DefaultPGNRenderer = &PGNRenderer{} + +// pgnRender holds the state for a single render pass. A fresh instance is +// created per Render/RenderGameTo call; PGNRenderer itself stays stateless. +// +// Cursor invariant: run() navigates the MoveTree's single active cursor +// (ADR-016) to read pre-move positions. It saves the caller's cursor on +// entry and restores it via defer, inside the tree != nil guard. Not safe +// for concurrent use on one Game; same constraint as the v3 slice. +type pgnRender struct { + g *Game + sb *strings.Builder +} + +// Render returns the PGN text for g. +func (r *PGNRenderer) Render(g *Game) string { + var sb strings.Builder + // strings.Builder.Write never fails; the error is unreachable here. + _ = r.RenderGameTo(g, &sb) + return sb.String() +} + +// RenderGameTo writes the PGN text for g to w. It returns any +// write error from w. +func (r *PGNRenderer) RenderGameTo(g *Game, w io.Writer) error { + sb, ok := w.(*strings.Builder) + if !ok { + sb = &strings.Builder{} + } + (&pgnRender{g: g, sb: sb}).run() + if ok { + return nil + } + _, err := io.WriteString(w, sb.String()) + return err +} + +func (p *pgnRender) run() { + g := p.g + sb := p.sb + + tags := g.tagPairs + if g.tree != nil && g.tree.rootPos != nil && g.tree.rootPos.variant == Chess960 { + tags = chess960PGNTags(g.tagPairs, g.tree.rootPos) + } + + tagPairList := make([]sortableTagPair, len(tags)) + var idx uint + for tag, value := range tags { + tagPairList[idx] = sortableTagPair{ + Key: tag, + Value: value, + } + idx++ + } + + slices.SortFunc(tagPairList, cmpTags) + + for _, tagPair := range tagPairList { + sb.WriteByte('[') + sb.WriteString(tagPair.Key) + sb.WriteString(" \"") + sb.WriteString(escapeTagValue(tagPair.Value)) + sb.WriteString("\"]\n") + } + + if len(g.tagPairs) > 0 { + sb.WriteString("\n") + } + + needTrailingSpace := false + if g.tree != nil && g.tree.Root() != nil { + // Rendering reads pre-move positions via MoveNode.Position(), which + // drives the tree's single active cursor (ADR-016). Save the cursor + // node here and restore it after the render so the tree's active + // position is left where the caller left it. + defer g.tree.setCurrent(g.tree.Current()) + root := g.tree.Root() + if len(root.children) > 0 { + // Root position is always available via tree.rootPos — no + // cursor navigation needed for the move count / side to move + // at the start of the game. + p.writeMoves(root, + g.tree.rootPos.moveCount, + g.tree.rootPos.turn == White, false, false, true) + needTrailingSpace = true + } else if root.hasAnnotations() { + p.writeAnnotations(root) + } + } + + if needTrailingSpace { + sb.WriteString(" ") + } + sb.WriteString(g.Outcome().String()) +} + +// sortableTagPair is the key/value row used to sort a Game's tag pairs into +// PGN output order. +type sortableTagPair struct { + Key string + Value string +} + +// cmpTags orders two tag pairs. The Seven Tag Roster (Event, Site, Date, +// Round, White, Black, Result) takes priority; everything else is sorted +// ascending by key. Duplicate keys are treated as equal so the sort is +// stable. +func cmpTags(a, b sortableTagPair) int { + // Don't re-order duplicate keys + if a.Key == b.Key { + return 0 + } + + // PGN defined tags take priority + for _, req := range []string{ + "Event", + "Site", + "Date", + "Round", + "White", + "Black", + "Result", + } { + if a.Key == req { + return -1 + } + if b.Key == req { + return +1 + } + } + + // Finally compare the keys directly and sort by ascending + if a.Key < b.Key { + return -1 + } else if b.Key < a.Key { + return +1 + } + return 0 +} + +// escapeTagValue escapes backslash and double-quote characters so that the +// resulting string is safe to embed inside a PGN tag value. +func escapeTagValue(v string) string { + var sb strings.Builder + for i := range len(v) { + c := v[i] + if c == '\\' || c == '"' { + sb.WriteByte('\\') + } + sb.WriteByte(c) + } + return sb.String() +} + +// writeMoves recursively writes the PGN-formatted move sequence starting from +// the given move node. It handles move numbering for white and black moves, +// encodes moves using algebraic notation based on the appropriate position, +// and appends comments and command annotations if present. The function +// distinguishes between main line moves and sub-variations; when processing a +// sub-variation, moves are enclosed in parentheses. +// +// The function recurses through the move tree, writing the main line first +// and then processing any additional variations, ensuring that the output +// adheres to standard PGN conventions. +// +// ponytail: subVariation/closedVariation/isRoot stay per-frame locals; +// a named-context cleanup is a separate follow-up, not this refactor. +func (p *pgnRender) writeMoves(node *MoveNode, moveNum int, isWhite bool, + subVariation, closedVariation, isRoot bool, +) { + // If no moves remain, stop. + if node == nil { + return + } + + // Handle root move comments before processing children + if isRoot && node.hasAnnotations() { + p.writeAnnotations(node) + } + + var currentMove *MoveNode + + // The main line is the first child. + if subVariation { + currentMove = node + } else { + if len(node.children) == 0 { + return // nothing to print if no child exists (should not happen for a proper game) + } + currentMove = node.children[0] + } + + p.writeMoveNumber(moveNum, isWhite, subVariation, closedVariation, isRoot) + + // Encode the move using your algebraicNotation. + p.writeMoveEncoding(currentMove) + + p.writeAnnotations(currentMove) + + if len(node.children) > 1 || len(currentMove.children) > 0 { + p.sb.WriteString(" ") + } + // Process any variations (children beyond the first). + // In PGN, variations are enclosed in parentheses. + closedVar := p.writeVariations(node, moveNum, isWhite) + + if len(currentMove.children) > 0 { + var nextMoveNum int + var nextIsWhite bool + if isWhite { + // After white's move, black plays using the same move number. + nextMoveNum = moveNum + nextIsWhite = false + } else { + // After black's move, increment move number. + nextMoveNum = moveNum + 1 + nextIsWhite = true + } + p.writeMoves(currentMove, nextMoveNum, nextIsWhite, false, closedVar, + false) + } +} + +func (p *pgnRender) writeMoveNumber(moveNum int, isWhite bool, + subVariation, closedVariation, isRoot bool, +) { + if closedVariation { + p.sb.WriteString(" ") + } + if isWhite { + p.sb.WriteString(strconv.Itoa(moveNum)) + p.sb.WriteString(". ") + } else if subVariation || closedVariation || isRoot { + p.sb.WriteString(strconv.Itoa(moveNum)) + p.sb.WriteString("... ") + } +} + +func (p *pgnRender) writeMoveEncoding(currentMove *MoveNode) { + if currentMove == nil || currentMove.parent == nil || currentMove.tree == nil { + return + } + // Look up the pre-move position via the tree cursor (Peek is no-copy; + // run saves/restores the active cursor for us). The synthetic root + // carries rootPos. + var prePos *Position + if currentMove.parent == currentMove.tree.Root() { + prePos = currentMove.tree.rootPos + } else { + // Navigate the cursor to the parent and read the live position + // (no alloc). SAN().Encode reads only, so we can safely alias the + // live cursor position. Relies on run's outer defer to restore the + // active cursor when the render returns. + currentMove.tree.setCurrent(currentMove.parent) + prePos = currentMove.tree.pos + } + moveStr, err := SAN().Encode(prePos, currentMove.move) + // ponytail: SAN encode errors are dropped silently. The only realistic + // cause is prePos == nil from tree corruption, which yields malformed + // PGN that downstream parsers reject — not silently-corrupt games. + if err == nil { + p.sb.WriteString(moveStr) + } +} + +func (p *pgnRender) writeAnnotations(move *MoveNode) { + if move == nil { + return + } + + for _, nag := range move.nags { + p.sb.WriteByte(' ') + p.sb.WriteString(nag) + } + + if len(move.commentBlocks) > 0 { + writeCommentBlocks(move.commentBlocks, p.sb) + } +} + +func writeCommentBlocks(blocks []CommentBlock, sb *strings.Builder) { + for _, block := range blocks { + if len(block.Items) == 0 { + continue + } + + sb.WriteString(" {") + lastByte := byte('{') + for _, item := range block.Items { + switch item.Kind { + case CommentText: + lastByte = writeEscapedCommentText(sb, item.Text, lastByte) + case CommentCommand: + if needsCommandSeparator(lastByte) { + sb.WriteString(" ") + } + sb.WriteString("[%") + sb.WriteString(item.Key) + sb.WriteString(" ") + sb.WriteString(item.Value) + sb.WriteString("]") + lastByte = ']' + } + } + sb.WriteString("}") + } +} + +func writeEscapedCommentText(sb *strings.Builder, text string, lastByte byte) byte { + for i := range len(text) { + if text[i] == '}' { + sb.WriteByte('\\') + } + sb.WriteByte(text[i]) + lastByte = text[i] + } + return lastByte +} + +func needsCommandSeparator(lastByte byte) bool { + return lastByte != ' ' +} + +func (p *pgnRender) writeVariations(node *MoveNode, moveNum int, isWhite bool) bool { + wroteAtLeastOneVar := false + + if len(node.children) > 1 { + for i := 1; i < len(node.children); i++ { + if wroteAtLeastOneVar { + p.sb.WriteString(" ") + } + wroteAtLeastOneVar = true + + variation := node.children[i] + p.sb.WriteString("(") + p.writeMoves(variation, moveNum, isWhite, true, false, false) + p.sb.WriteString(")") + } + } + + return wroteAtLeastOneVar +} + +// chess960PGNTags returns a copy of tags with the PGN tags required to +// round-trip a Chess960 game: Variant names the variant, and SetUp/FEN record +// the starting position. Existing tags are preserved unchanged. The returned +// map is always a fresh copy, so the game's own tag pairs are not mutated. +func chess960PGNTags(tags TagPairs, rootPos *Position) TagPairs { + out := make(TagPairs, len(tags)+3) + for k, v := range tags { + out[k] = v + } + if _, ok := out["Variant"]; !ok { + out["Variant"] = "Chess960" + } + if _, ok := out["SetUp"]; !ok { + out["SetUp"] = "1" + } + if _, ok := out["FEN"]; !ok { + out["FEN"] = rootPos.String() + } + return out +} diff --git a/pgn_renderer_internal_test.go b/pgn_renderer_internal_test.go new file mode 100644 index 00000000..5fb7188c --- /dev/null +++ b/pgn_renderer_internal_test.go @@ -0,0 +1,35 @@ +package chess + +import ( + "strings" + "testing" +) + +func TestWriteAnnotations(t *testing.T) { + t.Run("NilMove", func(t *testing.T) { + var sb strings.Builder + (&pgnRender{sb: &sb}).writeAnnotations(nil) + if sb.String() != "" { + t.Fatalf("expected empty annotation output, got %q", sb.String()) + } + }) + + t.Run("StructuredCommentAndCommand", func(t *testing.T) { + move := &MoveNode{} + move.SetComment("Good move") + move.SetCommand("clk", "0:05:00") + var sb strings.Builder + (&pgnRender{sb: &sb}).writeAnnotations(move) + if sb.String() != " {Good move [%clk 0:05:00]}" { + t.Fatalf("expected merged annotation, got %q", sb.String()) + } + }) + + t.Run("EmptyStructuredBlock", func(t *testing.T) { + var sb strings.Builder + writeCommentBlocks([]CommentBlock{{}}, &sb) + if sb.String() != "" { + t.Fatalf("expected empty structured block to be skipped, got %q", sb.String()) + } + }) +} diff --git a/pgn_renderer_test.go b/pgn_renderer_test.go new file mode 100644 index 00000000..99769653 --- /dev/null +++ b/pgn_renderer_test.go @@ -0,0 +1,287 @@ +package chess_test + +import ( + "bytes" + "errors" + "regexp" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +func TestPGNRenderer_RenderMatchesGameString(t *testing.T) { + g := chess.NewGame() + g.AddTagPair("Event", "Test Event") + g.AddTagPair("Site", "Test Site") + g.AddTagPair("Date", "2024.01.01") + g.AddTagPair("Round", "1") + g.AddTagPair("White", "Player A") + g.AddTagPair("Black", "Player B") + g.AddTagPair("Result", "*") + + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + if _, err := g.MoveText("e5", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + + got := g.String() + rendered := chess.DefaultPGNRenderer.Render(g) + if got != rendered { + t.Errorf("Game.String() and DefaultPGNRenderer.Render disagree:\n%s\nvs\n%s", got, rendered) + } +} + +func TestGame_WritePGNMatchesString(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("d4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + if _, err := g.MoveText("d5", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + + var buf bytes.Buffer + if err := g.WritePGN(&buf); err != nil { + t.Fatal(err) + } + + if buf.String() != g.String() { + t.Errorf("WritePGN output differs from String():\n%s\nvs\n%s", buf.String(), g.String()) + } +} + +type errWriter struct { + err error +} + +func (w *errWriter) Write(_ []byte) (int, error) { + return 0, w.err +} + +func TestPGNRenderer_RenderGameToPropagatesWriterError(t *testing.T) { + g := chess.NewGame() + want := errors.New("disk full") + w := &errWriter{err: want} + + err := chess.DefaultPGNRenderer.RenderGameTo(g, w) + if !errors.Is(err, want) { + t.Errorf("expected error %v, got %v", want, err) + } +} + +func TestPGNRenderer_EndsEmptyGameWithNoOutcome(t *testing.T) { + g := chess.NewGame() + out := chess.DefaultPGNRenderer.Render(g) + if !strings.HasSuffix(out, chess.NoOutcome.String()) { + t.Errorf("expected output to end with NoOutcome %q, got %q", chess.NoOutcome, out) + } +} + +func TestPGNRenderer_MoveNumberUsesDotAndSpace(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + if _, err := g.MoveText("e5", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + if _, err := g.MoveText("Nf3", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + + out := chess.DefaultPGNRenderer.Render(g) + + for _, pattern := range []string{`\b1\. e4\b`, ` 2\. Nf3\b`} { + re := regexp.MustCompile(pattern) + if !re.MatchString(out) { + t.Errorf("expected output to match %q, got %q", pattern, out) + } + } + if strings.Contains(out, "1.e4") || strings.Contains(out, "2.Nf3") { + t.Errorf("expected a space between move number and move, got %q", out) + } +} + +func TestPGNRenderer_TrailingSpaceAfterMoves(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + if _, err := g.MoveText("e5", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + out := chess.DefaultPGNRenderer.Render(g) + if !strings.HasSuffix(out, " *") { + t.Errorf("expected a single trailing space before outcome token in %q", out) + } +} + +func TestPGNRenderer_NoTrailingSpaceForEmptyGame(t *testing.T) { + g := chess.NewGame() + out := chess.DefaultPGNRenderer.Render(g) + if strings.HasSuffix(out, " *") { + t.Errorf("empty game must not gain a trailing space before outcome: %q", out) + } +} + +func TestPGNRenderer_EscapesCommentEndBrace(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + g.MoveTree().Root().Children()[0].SetComment("keeps } inside") + + out := chess.DefaultPGNRenderer.Render(g) + if !strings.Contains(out, `keeps \} inside`) { + t.Fatalf("rendered PGN did not escape comment brace: %q", out) + } + + parsed := chess.NewGame(mustPGNOption(t, out)) + if got := parsed.MoveTree().Root().Children()[0].Comments(); got != "keeps } inside" { + t.Fatalf("round-tripped comment = %q, want %q", got, "keeps } inside") + } +} + +func TestPGNRenderer_EscapesTagValueQuotes(t *testing.T) { + g := chess.NewGame() + g.AddTagPair("White", `A "B" C`) + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + + out := chess.DefaultPGNRenderer.Render(g) + if !strings.Contains(out, `A \"B\" C`) { + t.Fatalf("rendered PGN did not escape tag value quotes: %q", out) + } +} + +func TestPGNRenderer_EmitsCommandAnnotation(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + g.MoveTree().Root().Children()[0].SetCommand("clk", "0:01:23") + + out := chess.DefaultPGNRenderer.Render(g) + if !strings.Contains(out, "[%clk 0:01:23]") { + t.Fatalf("rendered PGN did not contain command annotation: %q", out) + } +} + +func TestPGNRenderer_OrdersTagsBySevenTagRosterThenAlpha(t *testing.T) { + g := chess.NewGame() + g.AddTagPair("Result", "*") + g.AddTagPair("Zebra", "z") + g.AddTagPair("Date", "2026.06.19") + g.AddTagPair("Black", "B") + g.AddTagPair("Alpha", "a") + g.AddTagPair("Round", "1") + g.AddTagPair("White", "A") + g.AddTagPair("Event", "E") + g.AddTagPair("Site", "S") + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + + out := chess.DefaultPGNRenderer.Render(g) + idx := func(tag string) int { return strings.Index(out, "["+tag+" \"") } + order := []string{"Event", "Site", "Date", "Round", "White", "Black", "Result", "Alpha", "Zebra"} + for i := 1; i < len(order); i++ { + if idx(order[i]) <= idx(order[i-1]) { + t.Fatalf("tags out of order: %q (idx %d) should come after %q (idx %d)\n%s", + order[i], idx(order[i]), order[i-1], idx(order[i-1]), out) + } + } +} + +func TestPGNRenderer_DoesNotMutateGame(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + g.MoveTree().Root().Children()[0].SetComment("a comment") + g.AddTagPair("Custom", "value") + + before := g.String() + beforePos := g.Position().XFENString() + _ = chess.DefaultPGNRenderer.Render(g) + if g.String() != before { + t.Errorf("Render mutated game string:\nbefore:\n%s\nafter:\n%s", before, g.String()) + } + if g.Position().XFENString() != beforePos { + t.Errorf("Render mutated position: before %q after %q", beforePos, g.Position().XFENString()) + } +} + +func TestPGNRenderer_RoundTripsVariations(t *testing.T) { + pgn := withMinimalTags("1. e4 {main} e5 (1...c5 {sicilian} 2. Nf3) 2. Nf3 *") + g := mustParseSingleGame(t, pgn) + + first := chess.DefaultPGNRenderer.Render(g) + reparsed := mustParseSingleGame(t, first) + second := chess.DefaultPGNRenderer.Render(reparsed) + + if first != second { + t.Fatalf("render not idempotent for variations:\nfirst:\n%s\nsecond:\n%s", first, second) + } + if !strings.Contains(first, "c5") { + t.Fatalf("variation move c5 missing from render: %q", first) + } +} + +func TestPGNRenderer_IsIdempotentOnAnnotations(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + g.MoveTree().Root().Children()[0].SetComment("best move") + if err := g.MoveTree().Root().Children()[0].SetNAGs([]string{"$1"}); err != nil { + t.Fatal(err) + } + if _, err := g.MoveText("e5", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + + first := chess.DefaultPGNRenderer.Render(g) + reparsed := chess.NewGame(mustPGNOption(t, first)) + second := chess.DefaultPGNRenderer.Render(reparsed) + + if first != second { + t.Fatalf("render not idempotent:\nfirst:\n%s\nsecond:\n%s", first, second) + } +} + +func TestPGNRenderer_RenderGameToStringsBuilderFastPath(t *testing.T) { + pgn := withMinimalTags("1. e4 {main} e5 (1...c5 {sicilian} 2. Nf3) 2. Nf3 *") + g := mustParseSingleGame(t, pgn) + + var sb strings.Builder + if err := chess.DefaultPGNRenderer.RenderGameTo(g, &sb); err != nil { + t.Fatal(err) + } + if got, want := sb.String(), chess.DefaultPGNRenderer.Render(g); got != want { + t.Errorf("RenderGameTo(*strings.Builder) and Render disagree:\n%s\nvs\n%s", got, want) + } +} + +func TestPGNRenderer_WritesNAGsBeforeComments(t *testing.T) { + g := chess.NewGame() + if _, err := g.MoveText("e4", chess.SAN(), nil); err != nil { + t.Fatal(err) + } + move := g.MoveTree().Root().Children()[0] + move.SetComment("best move") + // Multiple NAGs are kept in order and rendered as canonical "$N" before + // the comment, even when imported via symbolic spellings. + if err := move.SetNAGs([]string{"!", "$1406"}); err != nil { + t.Fatal(err) + } + + out := chess.DefaultPGNRenderer.Render(g) + if !strings.Contains(out, "e4 $1 $1406 {best move}") { + t.Fatalf("expected NAGs before comment, got:\n%s", out) + } +} diff --git a/pgn_result_test.go b/pgn_result_test.go new file mode 100644 index 00000000..e71e8911 --- /dev/null +++ b/pgn_result_test.go @@ -0,0 +1,85 @@ +package chess_test + +import ( + "errors" + "strings" + "testing" + + "github.com/corentings/chess/v3" +) + +func TestPGN_ResolvesOutcomeFromTagTokenAndBoard(t *testing.T) { + moves := "1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6" + scholarMate := "1. e4 e5 2. Bc4 Nc6 3. Qh5 Nf6?? 4. Qxf7#" + + tests := []struct { + name string + pgn string + wantErr bool + wantOutcome chess.Outcome + wantMethod chess.Method + }{ + {"tag_white_won", "[Result \"1-0\"]\n\n" + moves + " *", false, chess.WhiteWon, chess.NoMethod}, + {"tag_draw", "[Result \"1/2-1/2\"]\n\n" + moves + " *", false, chess.Draw, chess.NoMethod}, + {"tag_black_won", "[Result \"0-1\"]\n\n" + moves + " *", false, chess.BlackWon, chess.NoMethod}, + {"token_white_won", moves + " 1-0", false, chess.WhiteWon, chess.NoMethod}, + {"token_black_won", moves + " 0-1", false, chess.BlackWon, chess.NoMethod}, + {"token_no_outcome", moves + " *", false, chess.NoOutcome, chess.NoMethod}, + {"token_draw", moves + " 1/2-1/2", false, chess.Draw, chess.NoMethod}, + {"tag_token_agree", "[Result \"1-0\"]\n\n" + moves + " 1-0", false, chess.WhiteWon, chess.NoMethod}, + {"tag_token_conflict", "[Result \"0-1\"]\n\n" + moves + " 1-0", true, chess.NoOutcome, chess.NoMethod}, + {"board_checkmate_conflicts_with_tag", "[Result \"0-1\"]\n\n" + scholarMate + " 1-0", true, chess.NoOutcome, chess.NoMethod}, + {"board_checkmate_agrees_with_tag", "[Result \"1-0\"]\n\n" + scholarMate + " 1-0", false, chess.WhiteWon, chess.Checkmate}, + {"tag_overrides_star_token", "[Result \"0-1\"]\n\n" + moves + " *", false, chess.BlackWon, chess.NoMethod}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + g, err := chess.ParsePGN(strings.NewReader(tt.pgn)) + if tt.wantErr { + var pe *chess.ParserError + if !errors.As(err, &pe) { + t.Fatalf("expected *ParserError, got %T (%v)", err, err) + } + return + } + if err != nil { + t.Fatalf("unexpected error: %v", err) + } + if got := g.Outcome(); got != tt.wantOutcome { + t.Errorf("Outcome() = %v, want %v", got, tt.wantOutcome) + } + if got := g.Method(); got != tt.wantMethod { + t.Errorf("Method() = %v, want %v", got, tt.wantMethod) + } + }) + } +} + +func TestPGNDrawMovetextTokenRecognized(t *testing.T) { + g, err := chess.ParsePGN(strings.NewReader("1. e4 e5 1/2-1/2")) + if err != nil { + t.Fatal(err) + } + if got := g.Outcome(); got != chess.Draw { + t.Errorf("Outcome() = %v, want %v", got, chess.Draw) + } + if got := g.Method(); got != chess.NoMethod { + t.Errorf("Method() = %v, want %v", got, chess.NoMethod) + } +} + +func TestPGNTerminalVariationDoesNotSetMainLineOutcome(t *testing.T) { + g, err := chess.ParsePGN(strings.NewReader(` +[Result "*"] + +(1. f3 e5 2. g4 Qh4#) 1. e4 e5 *`)) + if err != nil { + t.Fatal(err) + } + if got := g.Outcome(); got != chess.NoOutcome { + t.Fatalf("Outcome() = %v, want %v", got, chess.NoOutcome) + } + if got := g.Method(); got != chess.NoMethod { + t.Fatalf("Method() = %v, want %v", got, chess.NoMethod) + } +} diff --git a/pgn_retain_vs_discard_benchmark_test.go b/pgn_retain_vs_discard_benchmark_test.go new file mode 100644 index 00000000..7ab3c0be --- /dev/null +++ b/pgn_retain_vs_discard_benchmark_test.go @@ -0,0 +1,78 @@ +package chess + +import ( + "bytes" + "errors" + "io" + "testing" +) + +// pgnBenchmarkSink keeps dead values alive across iterations without +// boxing into interface{} (which would corrupt the alloc measurement). +var pgnBenchmarkSink struct { + decoded int + games []*Game +} + +// BenchmarkPGNDecode_RetainAll keeps every decoded Game alive for the +// lifetime of the benchmark iteration. Positions are retained, so a sync.Pool +// for *Position cannot reclaim them mid-iteration -- this shape exposes the +// upper bound (no help from pooling). +func BenchmarkPGNDecode_RetainAll(b *testing.B) { + data := readPGNFixture("big_big.pgn") + b.SetBytes(int64(len(data))) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + var games []*Game + dec := NewPGNDecoder(bytes.NewReader(data)) + for { + g, err := dec.Decode() + if errors.Is(err, io.EOF) { + break + } + if err != nil { + if isKnownInconsistentPgn(err) { + continue + } + b.Fatalf("decode error: %v", err) + } + games = append(games, g) + } + pgnBenchmarkSink.games = games + } +} + +// BenchmarkPGNDecode_StreamDiscard decodes each game, reads one cheap field, +// and lets the *Game drop before the next iteration starts. Positions stay +// live within a single Game (move tree), so a pool cannot reclaim them +// mid-game in either shape; the discard shape only differs in cross-game +// reuse, which mallocgc already handles. Used to evaluate Fix C viability +// before any pooling is added. +func BenchmarkPGNDecode_StreamDiscard(b *testing.B) { + data := readPGNFixture("big_big.pgn") + b.SetBytes(int64(len(data))) + b.ReportAllocs() + b.ResetTimer() + + for range b.N { + var decoded int + dec := NewPGNDecoder(bytes.NewReader(data)) + for { + g, err := dec.Decode() + if errors.Is(err, io.EOF) { + break + } + if err != nil { + if isKnownInconsistentPgn(err) { + continue + } + b.Fatalf("decode error: %v", err) + } + _ = g.Outcome() + decoded++ + } + pgnBenchmarkSink.decoded = decoded + } +} diff --git a/pgn_test.go b/pgn_test.go index 8892366f..e74fb509 100644 --- a/pgn_test.go +++ b/pgn_test.go @@ -1,10 +1,14 @@ package chess import ( + "bytes" + "context" + "errors" "fmt" "io" "os" "path/filepath" + "reflect" "strings" "testing" ) @@ -68,12 +72,43 @@ var _ = []commentTest{ func BenchmarkPGN(b *testing.B) { pgn := mustParsePGN("fixtures/pgns/0001.pgn") b.ResetTimer() - for n := 0; n < b.N; n++ { + for range b.N { opt, _ := PGN(strings.NewReader(pgn)) NewGame(opt) } } +func TestNewParserSharesStartingPosition(t *testing.T) { + parser := NewParser(nil) + // The cursor's current position and the synthetic root's resolved + // position both point at the starting board. With the tree-owned cursor + // (ADR-016) they are value-equal but independent defensive copies. + got, want := parser.game.currentPosition(), parser.game.MoveTree().Root().Position() + if got == nil || want == nil { + t.Fatalf("nil position: got=%v want=%v", got, want) + } + if got.String() != want.String() { + t.Fatalf("starting position mismatch: got=%q want=%q", got, want) + } +} + +type errorTokenSource struct { + err error +} + +func (s errorTokenSource) NextToken() (Token, error) { + return Token{}, s.err +} + +func TestParserReportsInitialTokenSourceError(t *testing.T) { + wantErr := errors.New("token source failed") + + _, err := newParserFromSource(errorTokenSource{err: wantErr}).Parse() + if !errors.Is(err, wantErr) { + t.Fatalf("Parse() error = %v, want %v", err, wantErr) + } +} + func mustParsePGN(fname string) string { f, err := os.Open(fname) if err != nil { @@ -87,11 +122,17 @@ func mustParsePGN(fname string) string { return string(b) } +func isKnownInconsistentPgn(err error) bool { + if err == nil { + return false + } + return strings.Contains(err.Error(), "conflicts with") +} + func TestGamesFromPGN(t *testing.T) { for idx, test := range validPGNs { reader := strings.NewReader(test.PGN) - scanner := NewScanner(reader) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(reader).Decode() if err != nil { t.Fatalf("fail to parse game from valid pgn %d: %s", idx, err.Error()) } @@ -105,8 +146,7 @@ func TestGameWithVariations(t *testing.T) { pgn := mustParsePGN("fixtures/pgns/variations.pgn") reader := strings.NewReader(pgn) - scanner := NewScanner(reader) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(reader).Decode() if err != nil { t.Fatalf("fail to parse game from pgn: %s", err.Error()) } @@ -123,7 +163,7 @@ func TestGameWithVariations(t *testing.T) { t.Fatalf("game output blank") } - const expectedLastLine = "1. e4 (1. e3 e5) 1... e5 (1... d6 2. d4 Nf6 3. Nc3 e5 4. dxe5 (4. Nf3 Nbd7) 4... dxe5 5. Qxd8+ Kxd8) 2. Nf3 (2. Nc3 Nf6 3. f4) 2... Nc6 3. d4 exd4 4. Nxd4 *" + const expectedLastLine = "1. e4 (1. e3 e5) 1... e5 (1... d6 2. d4 Nf6 3. Nc3 e5 4. dxe5 (4. Nf3 Nbd7) 4... dxe5 5. Qxd8+ Kxd8) 2. Nf3 (2. Nc3 Nf6 3. f4) 2... Nc6 3. d4 exd4 4. Nxd4 1-0" lastLine := lines[len(lines)-1] if lastLine != expectedLastLine { t.Fatalf("game output not correct\n\tExpected:'%v'\n\tGot: '%v'\n", @@ -135,9 +175,7 @@ func TestSingleGameFromPGN(t *testing.T) { pgn := mustParsePGN("fixtures/pgns/single_game.pgn") reader := strings.NewReader(pgn) - scanner := NewScanner(reader) - - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(reader).Decode() if err != nil { t.Fatalf("fail to read games from valid pgn: %s", err.Error()) } @@ -179,7 +217,7 @@ func TestSingleGameFromPGN(t *testing.T) { t.Fatalf("game moves are not correct, expected 6, got %d", len(game.Moves())) } - for i, move := range game.Moves() { + for i, move := range game.MoveTree().MainLine() { // check move number for each move // Get the full move number fullMoveNumber := (i / 2) + 1 @@ -193,38 +231,35 @@ func TestSingleGameFromPGN(t *testing.T) { } // print all moves - moves := game.Moves() + moves := game.MoveTree().MainLine() - if moves[4].comments == "" { - t.Fatalf("game move 6 is not correct, expected comment, got %s", moves[5].comments) + if moves[4].Comments() == "" { + t.Fatalf("game move 6 is not correct, expected comment, got %s", moves[5].Comments()) } } func TestBigPgn(t *testing.T) { pgn := mustParsePGN("fixtures/pgns/big.pgn") - reader := strings.NewReader(pgn) - scanner := NewScanner(reader) count := 0 - - for scanner.HasNext() { + for record, err := range PGNRecords(context.Background(), strings.NewReader(pgn)) { count++ t.Run(fmt.Sprintf("big pgn : %d", count), func(t *testing.T) { - scannedGame, err := scanner.ScanGame() if err != nil { - t.Fatalf("fail to scan game from valid pgn: %s", err.Error()) - } - - tokens, err := TokenizeGame(scannedGame) - if err != nil { - t.Fatalf("fail to tokenize game from valid pgn: %s", err.Error()) + if isKnownInconsistentPgn(err) { + t.Skipf("skipping inconsistent real-world PGN: %s", err.Error()) + return + } + t.Fatalf("fail to read record: %s", err.Error()) } - raw := scannedGame.Raw - - parser := NewParser(tokens) - game, err := parser.Parse() + raw := record.Raw + game, err := parsePGNText(raw, defaultPGNOptions()) if err != nil { + if isKnownInconsistentPgn(err) { + t.Skipf("skipping inconsistent real-world PGN: %s", err.Error()) + return + } t.Fatalf("fail to read games from valid pgn: %s | %s", err.Error(), raw[:min(200, len(raw))]) } @@ -241,7 +276,7 @@ func TestBigPgn(t *testing.T) { t.Skip("Skipping test for From Position") } - for i, move := range game.Moves() { + for i, move := range game.MoveTree().MainLine() { // check move number for each move // Get the full move number fullMoveNumber := (i / 2) + 1 @@ -256,32 +291,21 @@ func TestBigPgn(t *testing.T) { } func TestBigBigPgn(t *testing.T) { - t.Skip("This test is too slow") pgn := mustParsePGN("fixtures/pgns/big_big.pgn") reader := strings.NewReader(pgn) - scanner := NewScanner(reader) + dec := NewPGNDecoder(reader) count := 0 - for scanner.HasNext() { + for { count++ + game, err := dec.Decode() + if errors.Is(err, io.EOF) { + break + } t.Run(fmt.Sprintf("bigbig pgn : %d", count), func(t *testing.T) { - scannedGame, err := scanner.ScanGame() - if err != nil { - t.Fatalf("fail to scan game from valid pgn: %s", err.Error()) - } - - tokens, err := TokenizeGame(scannedGame) if err != nil { - t.Fatalf("fail to tokenize game from valid pgn: %s", err.Error()) - } - - raw := scannedGame.Raw - - parser := NewParser(tokens) - game, err := parser.Parse() - if err != nil { - t.Fatalf("fail to read games from valid pgn: %s | %s", err.Error(), raw[:min(200, len(raw))]) + t.Fatalf("fail to read games from valid pgn: %s", err.Error()) } if game == nil { @@ -295,8 +319,7 @@ func TestCompleteGame(t *testing.T) { pgn := mustParsePGN("fixtures/pgns/complete_game.pgn") reader := strings.NewReader(pgn) - scanner := NewScanner(reader) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(reader).Decode() if err != nil { t.Fatalf("fail to read games from valid pgn: %s", err.Error()) } @@ -338,23 +361,23 @@ func TestCompleteGame(t *testing.T) { t.Fatalf("game move 1 is not correct, expected d4, got %s", game.Moves()[0].String()) } - if game.Moves()[0].comments != "" { - t.Fatalf("game move 1 is not correct, expected no comment, got %s", game.Moves()[0].comments) + if game.MoveTree().MainLine()[0].Comments() != "" { + t.Fatalf("game move 1 is not correct, expected no comment, got %s", game.MoveTree().MainLine()[0].Comments()) } // print all moves - moves := game.Moves() + moves := game.MoveTree().MainLine() - if game.Moves()[0].command["eval"] != "0.17" { - t.Fatalf("game move 1 is not correct, expected eval, got %s", game.Moves()[0].command["eval"]) + if got, ok := game.MoveTree().MainLine()[0].GetCommand("eval"); !ok || got != "0.17" { + t.Fatalf("game move 1 is not correct, expected eval, got %s", got) } - if moves[6].comments != "A57 Benko Gambit Declined: Main Line" { - t.Fatalf("game move 4 is not correct, expected comment, got %s", moves[6].comments) + if moves[6].Comments() != "A57 Benko Gambit Declined: Main Line" { + t.Fatalf("game move 4 is not correct, expected comment, got %s", moves[6].Comments()) } - if moves[44].nag != "?!" { - t.Fatalf("game move 44 is not correct, expected nag '!?', got %s", moves[44].nag) + if got := moves[44].NAGs(); !reflect.DeepEqual(got, []string{"$6"}) { + t.Fatalf("game move 44 is not correct, expected NAG '$6', got %v", got) } } @@ -364,10 +387,10 @@ func TestLichessMultipleCommand(t *testing.T) { t.Fatalf("Failed to open fixture file: %v", err) } - scanner := NewScanner(file) + dec := NewPGNDecoder(file) // Test first game - game, err := scanner.ParseNext() + game, err := dec.Decode() if err != nil { t.Fatalf("fail to read games from valid pgn: %s", err.Error()) } @@ -381,27 +404,27 @@ func TestLichessMultipleCommand(t *testing.T) { } // Check if move one has the correct command - if game.Moves()[0].command["eval"] != "0.0" { - t.Fatalf("game move 1 is not correct, expected eval, got %s", game.Moves()[0].command["eval"]) + if got, ok := game.MoveTree().MainLine()[0].GetCommand("eval"); !ok || got != "0.0" { + t.Fatalf("game move 1 is not correct, expected eval, got %s", got) } // Check for clock also - if game.Moves()[0].command["clk"] != "0:03:00" { - t.Fatalf("game move 1 is not correct, expected clock, got %s", game.Moves()[0].command["clk"]) + if got, ok := game.MoveTree().MainLine()[0].GetCommand("clk"); !ok || got != "0:03:00" { + t.Fatalf("game move 1 is not correct, expected clock, got %s", got) } // Check move 5 for comment and eval - if game.Moves()[4].comments != "E00 Catalan Opening" { - t.Fatalf("game move 5 is not correct, expected comment, got %s", game.Moves()[4].comments) + if game.MoveTree().MainLine()[4].Comments() != "E00 Catalan Opening" { + t.Fatalf("game move 5 is not correct, expected comment, got %s", game.MoveTree().MainLine()[4].Comments()) } - if game.Moves()[4].command["eval"] != "0.14" { - t.Fatalf("game move 5 is not correct, expected eval, got %s", game.Moves()[4].command["eval"]) + if got, ok := game.MoveTree().MainLine()[4].GetCommand("eval"); !ok || got != "0.14" { + t.Fatalf("game move 5 is not correct, expected eval, got %s", got) } // check for clock - if game.Moves()[4].command["clk"] != "0:02:58" { - t.Fatalf("game move 5 is not correct, expected clock, got %s", game.Moves()[4].command["clk"]) + if got, ok := game.MoveTree().MainLine()[4].GetCommand("clk"); !ok || got != "0:02:58" { + t.Fatalf("game move 5 is not correct, expected clock, got %s", got) } } @@ -416,28 +439,27 @@ func TestParseMoveWithNAGAndComment(t *testing.T) { 1. e4 $1 {Good move} e5 {Solid} $2 2. Nf3 $3 {Another comment} Nc6 $4 {Yet another}` - scanner := NewScanner(strings.NewReader(pgn)) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(strings.NewReader(pgn)).Decode() if err != nil { t.Fatalf("fail to parse game: %v", err) } - moves := game.Moves() + moves := game.MoveTree().MainLine() if len(moves) < 4 { t.Fatalf("expected at least 4 moves, got %d", len(moves)) } - if moves[0].nag == "" || moves[0].comments == "" { - t.Errorf("move 1 should have both NAG and comment, got nag: '%s', comment: '%s'", moves[0].nag, moves[0].comments) + if len(moves[0].NAGs()) == 0 || moves[0].Comments() == "" { + t.Errorf("move 1 should have both NAG and comment, got nags: '%v', comment: '%s'", moves[0].NAGs(), moves[0].Comments()) } - if moves[1].nag == "" || moves[1].comments == "" { - t.Errorf("move 2 should have both NAG and comment, got nag: '%s', comment: '%s'", moves[1].nag, moves[1].comments) + if len(moves[1].NAGs()) == 0 || moves[1].Comments() == "" { + t.Errorf("move 2 should have both NAG and comment, got nags: '%v', comment: '%s'", moves[1].NAGs(), moves[1].Comments()) } - if moves[2].nag == "" || moves[2].comments == "" { - t.Errorf("move 3 should have both NAG and comment, got nag: '%s', comment: '%s'", moves[2].nag, moves[2].comments) + if len(moves[2].NAGs()) == 0 || moves[2].Comments() == "" { + t.Errorf("move 3 should have both NAG and comment, got nags: '%v', comment: '%s'", moves[2].NAGs(), moves[2].Comments()) } - if moves[3].nag == "" || moves[3].comments == "" { - t.Errorf("move 4 should have both NAG and comment, got nag: '%s', comment: '%s'", moves[3].nag, moves[3].comments) + if len(moves[3].NAGs()) == 0 || moves[3].Comments() == "" { + t.Errorf("move 4 should have both NAG and comment, got nags: '%v', comment: '%s'", moves[3].NAGs(), moves[3].Comments()) } } @@ -452,21 +474,20 @@ func TestVariationComments(t *testing.T) { 1. e4 {main line comment} e5 (1... d5 {variation comment on d5} 2. exd5 {variation comment on exd5} Qxd5) 2. Nf3 Nc6 *` - scanner := NewScanner(strings.NewReader(pgn)) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(strings.NewReader(pgn)).Decode() if err != nil { t.Fatalf("fail to parse game: %v", err) } // Check main line comment on 1. e4 - mainMoves := game.Moves() - if mainMoves[0].comments != "main line comment" { - t.Errorf("expected main line comment on e4, got %q", mainMoves[0].comments) + mainMoves := game.MoveTree().MainLine() + if mainMoves[0].Comments() != "main line comment" { + t.Errorf("expected main line comment on e4, got %q", mainMoves[0].Comments()) } // 1... e5 is mainMoves[1], and its parent (rootMove child for e4) should have // a second child which is the variation 1... d5 - e4Move := game.rootMove.children[0] // 1. e4 + e4Move := game.MoveTree().Root().children[0] // 1. e4 if len(e4Move.children) < 2 { t.Fatalf("expected at least 2 children on e4 (main line e5 + variation d5), got %d", len(e4Move.children)) } @@ -474,8 +495,8 @@ func TestVariationComments(t *testing.T) { // First child is the main line 1... e5 // Second child is the variation 1... d5 d5Move := e4Move.children[1] - if d5Move.comments != "variation comment on d5" { - t.Errorf("expected 'variation comment on d5' on 1...d5, got %q", d5Move.comments) + if d5Move.Comments() != "variation comment on d5" { + t.Errorf("expected 'variation comment on d5' on 1...d5, got %q", d5Move.Comments()) } // d5's first child should be 2. exd5 @@ -483,8 +504,8 @@ func TestVariationComments(t *testing.T) { t.Fatalf("expected children on d5 variation move") } exd5Move := d5Move.children[0] - if exd5Move.comments != "variation comment on exd5" { - t.Errorf("expected 'variation comment on exd5' on 2.exd5, got %q", exd5Move.comments) + if exd5Move.Comments() != "variation comment on exd5" { + t.Errorf("expected 'variation comment on exd5' on 2.exd5, got %q", exd5Move.Comments()) } } @@ -499,40 +520,39 @@ func TestVariationNAGs(t *testing.T) { 1. e4 e5 (1... d5 $1 {great move} 2. exd5 $6 Qxd5 $2) 2. Nf3 *` - scanner := NewScanner(strings.NewReader(pgn)) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(strings.NewReader(pgn)).Decode() if err != nil { t.Fatalf("fail to parse game: %v", err) } // Find the variation: 1... d5 - e4Move := game.rootMove.children[0] + e4Move := game.MoveTree().Root().children[0] if len(e4Move.children) < 2 { t.Fatalf("expected variation on e4, got %d children", len(e4Move.children)) } d5Move := e4Move.children[1] - if d5Move.nag != "$1" { - t.Errorf("expected NAG '$1' on 1...d5, got %q", d5Move.nag) + if got := d5Move.NAGs(); !reflect.DeepEqual(got, []string{"$1"}) { + t.Errorf("expected NAG '$1' on 1...d5, got %v", got) } - if d5Move.comments != "great move" { - t.Errorf("expected comment 'great move' on 1...d5, got %q", d5Move.comments) + if d5Move.Comments() != "great move" { + t.Errorf("expected comment 'great move' on 1...d5, got %q", d5Move.Comments()) } if len(d5Move.children) == 0 { t.Fatalf("expected children on d5") } exd5Move := d5Move.children[0] - if exd5Move.nag != "$6" { - t.Errorf("expected NAG '$6' on 2.exd5, got %q", exd5Move.nag) + if got := exd5Move.NAGs(); !reflect.DeepEqual(got, []string{"$6"}) { + t.Errorf("expected NAG '$6' on 2.exd5, got %v", got) } if len(exd5Move.children) == 0 { t.Fatalf("expected children on exd5") } qxd5Move := exd5Move.children[0] - if qxd5Move.nag != "$2" { - t.Errorf("expected NAG '$2' on 2...Qxd5, got %q", qxd5Move.nag) + if got := qxd5Move.NAGs(); !reflect.DeepEqual(got, []string{"$2"}) { + t.Errorf("expected NAG '$2' on 2...Qxd5, got %v", got) } } @@ -547,26 +567,25 @@ func TestVariationCommands(t *testing.T) { 1. e4 e5 (1... d5 {good move [%eval -0.5] [%clk 0:05:00]} 2. exd5) 2. Nf3 *` - scanner := NewScanner(strings.NewReader(pgn)) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(strings.NewReader(pgn)).Decode() if err != nil { t.Fatalf("fail to parse game: %v", err) } - e4Move := game.rootMove.children[0] + e4Move := game.MoveTree().Root().children[0] if len(e4Move.children) < 2 { t.Fatalf("expected variation on e4, got %d children", len(e4Move.children)) } d5Move := e4Move.children[1] - if d5Move.comments != "good move" { - t.Errorf("expected comment 'good move' on 1...d5, got %q", d5Move.comments) + if d5Move.Comments() != "good move" { + t.Errorf("expected comment 'good move' on 1...d5, got %q", d5Move.Comments()) } - if d5Move.command["eval"] != "-0.5" { - t.Errorf("expected eval command '-0.5' on 1...d5, got %q", d5Move.command["eval"]) + if got, ok := d5Move.GetCommand("eval"); !ok || got != "-0.5" { + t.Errorf("expected eval command '-0.5' on 1...d5, got %q", got) } - if d5Move.command["clk"] != "0:05:00" { - t.Errorf("expected clk command '0:05:00' on 1...d5, got %q", d5Move.command["clk"]) + if got, ok := d5Move.GetCommand("clk"); !ok || got != "0:05:00" { + t.Errorf("expected clk command '0:05:00' on 1...d5, got %q", got) } } @@ -581,21 +600,20 @@ func TestNestedVariationComments(t *testing.T) { 1. e4 e5 2. Nf3 Nc6 3. Bb5 {Ruy Lopez} (3. Bc4 {Italian Game} Nf6 (3... Bc5 {Giuoco Piano}) 4. d3) 3... a6 *` - scanner := NewScanner(strings.NewReader(pgn)) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(strings.NewReader(pgn)).Decode() if err != nil { t.Fatalf("fail to parse game: %v", err) } // Main line: 3. Bb5 should have comment "Ruy Lopez" - mainMoves := game.Moves() + mainMoves := game.MoveTree().MainLine() // Moves: e4, e5, Nf3, Nc6, Bb5, a6 => index 4 is Bb5 if len(mainMoves) < 5 { t.Fatalf("expected at least 5 main line moves, got %d", len(mainMoves)) } bb5Move := mainMoves[4] - if bb5Move.comments != "Ruy Lopez" { - t.Errorf("expected 'Ruy Lopez' comment on 3.Bb5, got %q", bb5Move.comments) + if bb5Move.Comments() != "Ruy Lopez" { + t.Errorf("expected 'Ruy Lopez' comment on 3.Bb5, got %q", bb5Move.Comments()) } // Variation: 3. Bc4 should have comment "Italian Game" @@ -604,8 +622,8 @@ func TestNestedVariationComments(t *testing.T) { t.Fatalf("expected variation at move 3, got %d children", len(nc6Move.children)) } bc4Move := nc6Move.children[1] - if bc4Move.comments != "Italian Game" { - t.Errorf("expected 'Italian Game' comment on 3.Bc4, got %q", bc4Move.comments) + if bc4Move.Comments() != "Italian Game" { + t.Errorf("expected 'Italian Game' comment on 3.Bc4, got %q", bc4Move.Comments()) } // Nested variation: 3... Bc5 should have comment "Giuoco Piano" @@ -613,8 +631,8 @@ func TestNestedVariationComments(t *testing.T) { t.Fatalf("expected nested variation on Bc4, got %d children", len(bc4Move.children)) } bc5Move := bc4Move.children[1] - if bc5Move.comments != "Giuoco Piano" { - t.Errorf("expected 'Giuoco Piano' comment on 3...Bc5, got %q", bc5Move.comments) + if bc5Move.Comments() != "Giuoco Piano" { + t.Errorf("expected 'Giuoco Piano' comment on 3...Bc5, got %q", bc5Move.Comments()) } } @@ -629,17 +647,13 @@ func TestRoundTripWithVariationsAndCommandAnnotations(t *testing.T) { 1. e4 e5 2. Nf3 Nc6 3. Bb5 {Ruy Lopez} (3. Bc4 {Italian Game} Nf6 (3... Bc5 {Giuoco Piano}) 4. d3) 3... a6 *` - base := NewScanner(strings.NewReader(pgn)) - if !base.HasNext() { - t.Fatal("expected one game in input pgn") - } - game, err := base.ParseNext() + game, err := NewPGNDecoder(strings.NewReader(pgn)).Decode() if err != nil { t.Fatalf("failed to parse input pgn: %v", err) } - var walk func(*Move) - walk = func(m *Move) { + var walk func(*MoveNode) + walk = func(m *MoveNode) { if m == nil { return } @@ -650,7 +664,7 @@ func TestRoundTripWithVariationsAndCommandAnnotations(t *testing.T) { walk(child) } } - walk(game.GetRootMove()) + walk(game.MoveTree().Root()) roundTrip := game.String() @@ -673,7 +687,7 @@ func TestPGNAnnotationFidelityRoundTrip(t *testing.T) { pgn := withMinimalTags(`1. e4 {Good move [%clk 0:05:00]} {second [%eval 0.25]} *`) game := mustParseSingleGame(t, pgn) - move := game.Moves()[0] + move := game.MoveTree().MainLine()[0] if move.Comments() != "Good move second" { t.Fatalf("expected flattened comments, got %q", move.Comments()) } @@ -687,7 +701,7 @@ func TestPGNAnnotationFidelityRoundTrip(t *testing.T) { } reparsed := mustParseSingleGame(t, roundTrip) - blocks := reparsed.Moves()[0].CommentBlocks() + blocks := reparsed.MoveTree().MainLine()[0].CommentBlocks() if len(blocks) != 2 { t.Fatalf("expected 2 comment blocks, got %#v", blocks) } @@ -703,7 +717,7 @@ func TestPGNAnnotationFidelityPreservesOrderAndDuplicateCommands(t *testing.T) { game := mustParseSingleGame(t, pgn) roundTrip := game.String() reparsed := mustParseSingleGame(t, roundTrip) - move := reparsed.Moves()[0] + move := reparsed.MoveTree().MainLine()[0] if got, ok := move.GetCommand("clk"); !ok || got != "0:04:59" { t.Fatalf("expected last duplicate clk command, got %q, %v", got, ok) @@ -726,7 +740,7 @@ func TestPGNAnnotationFidelityPreservesOrderAndDuplicateCommands(t *testing.T) { func TestPGNAnnotationFidelityCommandUsesFirstParameter(t *testing.T) { game := mustParseSingleGame(t, withMinimalTags(`1. e4 {[%command 1:45:12,Nf6,"very interesting, but wrong"]} *`)) - move := game.Moves()[0] + move := game.MoveTree().MainLine()[0] if got, ok := move.GetCommand("command"); !ok || got != "1:45:12" { t.Fatalf("expected first command parameter, got %q, %v", got, ok) @@ -746,7 +760,7 @@ func TestPGNAnnotationFidelityVariationsAndExpansion(t *testing.T) { roundTrip := game.String() reparsed := mustParseSingleGame(t, roundTrip) - e4 := reparsed.Moves()[0] + e4 := reparsed.MoveTree().MainLine()[0] if len(e4.Children()) < 2 { t.Fatalf("expected e4 variation, got %d children", len(e4.Children())) } @@ -758,9 +772,12 @@ func TestPGNAnnotationFidelityVariationsAndExpansion(t *testing.T) { assertCommentItem(t, blocks[0].Items[0], CommentText, "Sicilian", "", "") assertCommentItem(t, blocks[0].Items[1], CommentCommand, "", "eval", "0.12") - scanner := NewScanner(strings.NewReader(roundTrip), WithExpandVariations()) - for scanner.HasNext() { - if _, err := scanner.ParseNext(); err != nil { + dec := NewPGNDecoder(strings.NewReader(roundTrip), WithPGNExpandVariations()) + for { + if _, err := dec.Decode(); err != nil { + if errors.Is(err, io.EOF) { + break + } t.Fatalf("expanded annotated variation should parse: %v", err) } } @@ -768,10 +785,10 @@ func TestPGNAnnotationFidelityVariationsAndExpansion(t *testing.T) { func TestPGNAnnotationFidelityLegacyAPIsAndDefensiveCopies(t *testing.T) { game := NewGame() - if err := game.PushMove("e4", nil); err != nil { + if _, err := game.MoveText("e4", SAN(), nil); err != nil { t.Fatal(err) } - move := game.Moves()[0] + move := game.MoveTree().MainLine()[0] move.SetComment("Good move") move.SetCommand("clk", "0:05:00") move.SetCommand("clk", "0:04:59") @@ -788,7 +805,7 @@ func TestPGNAnnotationFidelityLegacyAPIsAndDefensiveCopies(t *testing.T) { } parsed := mustParseSingleGame(t, withMinimalTags(`1. e4 {Good [%clk 0:05:00]} *`)) - parsedMove := parsed.Moves()[0] + parsedMove := parsed.MoveTree().MainLine()[0] blocks := parsedMove.CommentBlocks() blocks[0].Items[0].Text = "mutated" blocks[0].Items = append(blocks[0].Items, CommentItem{Kind: CommentCommand, Key: "eval", Value: "9"}) @@ -800,10 +817,30 @@ func TestPGNAnnotationFidelityLegacyAPIsAndDefensiveCopies(t *testing.T) { } } +// TestPGNCommentCommandMergingIssue104 is a regression test for issue #104: +// a parsed text comment followed by SetCommand must merge into a single +// comment block rather than emitting two separate {} blocks. v3's +// SetCommand appends to the last block when no matching key exists, so +// this pins the single-block contract. See the reporter's v2 scenario. +func TestPGNCommentCommandMergingIssue104(t *testing.T) { + game := mustParseSingleGame(t, withMinimalTags(`1. e4 {Ruy Lopez} *`)) + move := game.MoveTree().MainLine()[0] + move.SetCommand("eval", "0.25") + + roundTrip := game.String() + want := "{Ruy Lopez [%eval 0.25]}" + if !strings.Contains(roundTrip, want) { + t.Fatalf("expected merged single block %q in:\n%s", want, roundTrip) + } + // The two-block failure mode would look like "{Ruy Lopez} {[%eval 0.25]}". + if strings.Contains(roundTrip, "{Ruy Lopez} {") { + t.Fatalf("expected single merged block, got two separate blocks:\n%s", roundTrip) + } +} + func mustParseSingleGame(t *testing.T, pgn string) *Game { t.Helper() - scanner := NewScanner(strings.NewReader(pgn)) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(strings.NewReader(pgn)).Decode() if err != nil { t.Fatalf("failed to parse pgn: %v", err) } @@ -892,6 +929,49 @@ func TestParserAnnotationErrors(t *testing.T) { t.Fatal("expected unterminated command error") } }) + + t.Run("ParseMoveJoinsMismatchReasons", func(t *testing.T) { + // Position: white rook on a1 and bishop on c1, both can reach e1. + // Asking for "Nxe1" (knight captures e1) should fail with reasons + // from both candidates joined into a single ParserError. + opt, err := FEN("1k6/8/8/8/8/8/8/1BR4K w - - 0 1") + if err != nil { + t.Fatalf("FEN: %v", err) + } + g := NewGame(opt) + parser := NewParser([]Token{ + {Type: PIECE, Value: "N"}, + {Type: CAPTURE, Value: "x"}, + {Type: SQUARE, Value: "e1"}, + }) + parser.game = g + _, err = parser.parseMove() + if err == nil { + t.Fatal("expected parser error for Nxe1") + } + var pe *ParserError + if !errors.As(err, &pe) { + t.Fatalf("expected *ParserError, got %T: %v", err, err) + } + if !strings.Contains(pe.Message, "piece type mismatch") { + t.Errorf("expected joined message to contain 'piece type mismatch', got %q", pe.Message) + } + }) + + t.Run("DuplicateCommandName", func(t *testing.T) { + parser := NewParser([]Token{ + {Type: CommandStart, Value: "[%"}, + {Type: CommandName, Value: "clk"}, + {Type: CommandParam, Value: "0:05:00"}, + {Type: CommandName, Value: "eval"}, + {Type: CommandParam, Value: "0.24"}, + {Type: CommandEnd, Value: "]"}, + }) + _, err := parser.parseCommand() + if err == nil { + t.Fatal("expected parseCommand error for duplicate command name") + } + }) } func TestParserVariationErrors(t *testing.T) { @@ -932,6 +1012,9 @@ func TestParserVariationErrors(t *testing.T) { func TestParseResultDraw(t *testing.T) { parser := NewParser([]Token{{Type: RESULT, Value: "1/2-1/2"}}) parser.parseResult() + if err := parser.resolveOutcome(); err != nil { + t.Fatal(err) + } if parser.game.Outcome() != Draw { t.Fatalf("expected draw outcome, got %s", parser.game.Outcome()) } @@ -948,38 +1031,37 @@ func TestVariationMoveNumbers(t *testing.T) { 1. e4 e5 2. Nf3 Nc6 3. Bb5 (3. Bc4 Nf6 4. d3) a6 4. Ba4 Nf6 5. O-O Be7 1-0` - scanner := NewScanner(strings.NewReader(pgn)) - game, err := scanner.ParseNext() + game, err := NewPGNDecoder(strings.NewReader(pgn)).Decode() if err != nil { t.Fatalf("fail to parse game: %v", err) } // Helper to recursively check move numbers - var checkMoveNumbers func(m *Move, expectedNum int) - checkMoveNumbers = func(m *Move, expectedNum int) { + var checkMoveNumbers func(m *MoveNode, expectedNum int) + checkMoveNumbers = func(m *MoveNode, expectedNum int) { fullMove := (expectedNum-1)/2 + 1 for _, child := range m.children { - if child.number != 0 && int(child.Ply()) != expectedNum { - t.Errorf("move %s: expected move number %d, got %d", child.String(), expectedNum, child.Ply()) + if child.number != 0 && child.Ply() != expectedNum { + t.Errorf("move %s: expected move number %d, got %d", child.Move().String(), expectedNum, child.Ply()) } if child.FullMoveNumber() != fullMove { - t.Errorf("move %s: expected full move number %d, got %d", child.String(), fullMove, child.FullMoveNumber()) + t.Errorf("move %s: expected full move number %d, got %d", child.Move().String(), fullMove, child.FullMoveNumber()) } - // If this move starts a variation, the move number should be correct for the branch + // If this move starts a variation, the move number should be correct for the variation checkMoveNumbers(child, expectedNum+1) } } - t.Logf("Root move number: %d", game.rootMove.number) - t.Logf("Root move ply: %d", game.rootMove.Ply()) - t.Logf("Root move full move number: %d", game.rootMove.FullMoveNumber()) - t.Logf("Second move: %v", game.rootMove.Children()[0]) + t.Logf("Root move number: %d", game.MoveTree().Root().number) + t.Logf("Root move ply: %d", game.MoveTree().Root().Ply()) + t.Logf("Root move full move number: %d", game.MoveTree().Root().FullMoveNumber()) + t.Logf("Second move: %v", game.MoveTree().Root().Children()[0]) // Mainline starts at move 1 - checkMoveNumbers(game.rootMove, 1) + checkMoveNumbers(game.MoveTree().Root(), 1) - // Check specific variation branch - mainMoves := game.Moves() + // Check specific variation + mainMoves := game.MoveTree().MainLine() if len(mainMoves) < 3 { t.Fatalf("expected at least 3 mainline moves, got %d", len(mainMoves)) } @@ -1007,16 +1089,40 @@ func BenchmarkPGNWithVariations(b *testing.B) { 1. e4 e5 2. Nf3 Nc6 3. Bb5 (3. Bc4 Nf6 4. d3) a6 4. Ba4 Nf6 5. O-O Be7 1-0` - scanner := NewScanner(strings.NewReader(pgn)) - b.ReportAllocs() b.ResetTimer() - for i := 0; i < b.N; i++ { - // Reset scanner for each iteration - scanner = NewScanner(strings.NewReader(pgn)) - _, err := scanner.ParseNext() + for range b.N { + _, err := NewPGNDecoder(strings.NewReader(pgn)).Decode() if err != nil { b.Fatalf("parse error: %v", err) } } } + +// readPGNFixture returns the raw bytes of a fixture PGN file. +func readPGNFixture(name string) []byte { + data, err := os.ReadFile(filepath.Join("fixtures", "pgns", name)) + if err != nil { + panic(err) + } + return data +} + +// pgnFixtureMeta reports size and game count for a fixture file. +type pgnFixtureMeta struct { + path string + size int64 + games int + perGame int // approximate bytes per game +} + +func pgnMeta(name string) pgnFixtureMeta { + data := readPGNFixture(name) + games := bytes.Count(data, []byte("[Event ")) + return pgnFixtureMeta{ + path: filepath.Join("fixtures", "pgns", name), + size: int64(len(data)), + games: games, + perGame: len(data) / max(games, 1), + } +} diff --git a/piece.go b/piece.go index bca3e91c..f628c270 100644 --- a/piece.go +++ b/piece.go @@ -1,6 +1,9 @@ package chess -import "strings" +import ( + "fmt" + "strings" +) // Color represents the color of a chess piece. type Color int8 @@ -14,14 +17,26 @@ const ( Black ) -func ColorFromString(s string) Color { +// ParseColor converts a FEN side-to-move character ("w" or "b") to a Color. +// It returns an error for any other input. +func ParseColor(s string) (Color, error) { switch strings.ToLower(s) { case "w": - return White + return White, nil case "b": - return Black + return Black, nil } - return NoColor + return NoColor, fmt.Errorf("chess: invalid color %q", s) +} + +// ColorFromString converts a FEN side-to-move character ("w" or "b") to a Color. +// Returns NoColor for any other input. +// +// Deprecated: use ParseColor for new code; it distinguishes parse failures from +// the NoColor sentinel. +func ColorFromString(s string) Color { + c, _ := ParseColor(s) + return c } // Other returns the opposite color of the receiver. @@ -83,29 +98,54 @@ func PieceTypes() [6]PieceType { return [6]PieceType{King, Queen, Rook, Bishop, Knight, Pawn} } -func PieceTypeFromByte(b byte) PieceType { +// ParsePieceTypeFromByte parses a FEN piece-type character (case-insensitive) +// into a PieceType. It returns an error for any other byte. +func ParsePieceTypeFromByte(b byte) (PieceType, error) { switch b { - case 'k': - return King - case 'q': - return Queen - case 'r': - return Rook - case 'b': - return Bishop - case 'n': - return Knight - case 'p': - return Pawn + case 'k', 'K': + return King, nil + case 'q', 'Q': + return Queen, nil + case 'r', 'R': + return Rook, nil + case 'b', 'B': + return Bishop, nil + case 'n', 'N': + return Knight, nil + case 'p', 'P': + return Pawn, nil } - return NoPieceType + return NoPieceType, fmt.Errorf("chess: invalid piece type byte %q", b) } -func PieceTypeFromString(s string) PieceType { +// PieceTypeFromByte parses a FEN piece-type character (case-insensitive) into a +// PieceType. Returns NoPieceType for any other byte. +// +// Deprecated: use ParsePieceTypeFromByte for new code; it distinguishes parse +// failures from the NoPieceType sentinel. +func PieceTypeFromByte(b byte) PieceType { + pt, _ := ParsePieceTypeFromByte(b) + return pt +} + +// ParsePieceType parses a single-character piece notation into a PieceType. +// It returns an error if the input is empty or longer than one character, or +// if the character is not a valid piece type. +func ParsePieceType(s string) (PieceType, error) { if len(s) != 1 { - return NoPieceType + return NoPieceType, fmt.Errorf("chess: invalid piece type %q", s) } - return PieceTypeFromByte(strings.ToLower(s)[0]) + return ParsePieceTypeFromByte(strings.ToLower(s)[0]) +} + +// PieceTypeFromString parses a single-character piece notation into a +// PieceType. Returns NoPieceType for invalid input. +// +// Deprecated: use ParsePieceType for new code; it distinguishes parse failures +// from the NoPieceType sentinel. +func PieceTypeFromString(s string) PieceType { + pt, _ := ParsePieceType(s) + return pt } func (p PieceType) String() string { @@ -202,45 +242,49 @@ var allPieces = [12]Piece{ BlackKing, BlackQueen, BlackRook, BlackBishop, BlackKnight, BlackPawn, } +//nolint:gochecknoglobals // Immutable lookup tables. +var ( + pieceTypes = [13]PieceType{ + NoPieceType, + King, Queen, Rook, Bishop, Knight, Pawn, + King, Queen, Rook, Bishop, Knight, Pawn, + } + pieceColors = [13]Color{ + NoColor, + White, White, White, White, White, White, + Black, Black, Black, Black, Black, Black, + } +) + // NewPiece returns the piece matching the PieceType and Color. // NoPiece is returned if the PieceType or Color isn't valid. func NewPiece(t PieceType, c Color) Piece { - for _, p := range allPieces { - if p.Color() == c && p.Type() == t { - return p - } + if t < King || t > Pawn { + return NoPiece + } + switch c { + case White: + return Piece(t) + case Black: + return Piece(int(t) + 6) } return NoPiece } // Type returns the type of the piece. func (p Piece) Type() PieceType { - switch p { - case WhiteKing, BlackKing: - return King - case WhiteQueen, BlackQueen: - return Queen - case WhiteRook, BlackRook: - return Rook - case WhiteBishop, BlackBishop: - return Bishop - case WhiteKnight, BlackKnight: - return Knight - case WhitePawn, BlackPawn: - return Pawn + if p < NoPiece || int(p) >= len(pieceTypes) { + return NoPieceType } - return NoPieceType + return pieceTypes[p] } // Color returns the color of the piece. func (p Piece) Color() Color { - switch p { - case WhiteKing, WhiteQueen, WhiteRook, WhiteBishop, WhiteKnight, WhitePawn: - return White - case BlackKing, BlackQueen, BlackRook, BlackBishop, BlackKnight, BlackPawn: - return Black + if p < NoPiece || int(p) >= len(pieceColors) { + return NoColor } - return NoColor + return pieceColors[p] } // String implements the fmt.Stringer interface. @@ -252,7 +296,7 @@ func (p Piece) String() string { } // DarkString is equivalent to String() except colors reversed for terminal -// windows in dark mode +// windows in dark mode. func (p Piece) DarkString() string { return pieceDarkUnicodes[int(p)] } diff --git a/piece_test.go b/piece_test.go index 5b807ee0..b588a71c 100644 --- a/piece_test.go +++ b/piece_test.go @@ -1,47 +1,380 @@ -package chess +package chess_test import ( "bytes" + "fmt" "testing" + + "github.com/corentings/chess/v3" ) -func TestPieceString(t *testing.T) { - tables := []struct { - piece PieceType - str string +func TestPieceType_FENString(t *testing.T) { + t.Parallel() + tests := []struct { + name string + pt chess.PieceType + want string + }{ + {"king", chess.King, "k"}, + {"queen", chess.Queen, "q"}, + {"rook", chess.Rook, "r"}, + {"bishop", chess.Bishop, "b"}, + {"knight", chess.Knight, "n"}, + {"pawn", chess.Pawn, "p"}, + {"none", chess.NoPieceType, ""}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + if got := tt.pt.String(); got != tt.want { + t.Errorf("String() = %q, want %q", got, tt.want) + } + }) + } +} + +func TestPieceType_Bytes(t *testing.T) { + t.Parallel() + tests := []struct { + name string + pt chess.PieceType + want []byte + }{ + {"king", chess.King, []byte{'k'}}, + {"queen", chess.Queen, []byte{'q'}}, + {"rook", chess.Rook, []byte{'r'}}, + {"bishop", chess.Bishop, []byte{'b'}}, + {"knight", chess.Knight, []byte{'n'}}, + {"pawn", chess.Pawn, []byte{'p'}}, + {"none", chess.NoPieceType, []byte{}}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + if !bytes.Equal(tt.pt.Bytes(), tt.want) { + t.Errorf("Bytes() = %v, want %v", tt.pt.Bytes(), tt.want) + } + }) + } +} + +func TestPieceType_ToPolyglotPromotionValue(t *testing.T) { + t.Parallel() + tests := []struct { + name string + pt chess.PieceType + want int + }{ + {"knight", chess.Knight, 1}, + {"bishop", chess.Bishop, 2}, + {"rook", chess.Rook, 3}, + {"queen", chess.Queen, 4}, + {"king_is_zero", chess.King, 0}, + {"pawn_is_zero", chess.Pawn, 0}, + {"none_is_zero", chess.NoPieceType, 0}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + if got := tt.pt.ToPolyglotPromotionValue(); got != tt.want { + t.Errorf("ToPolyglotPromotionValue() = %d, want %d", got, tt.want) + } + }) + } +} + +func TestPieceType_StringRoundTrip(t *testing.T) { + t.Parallel() + for _, pt := range chess.PieceTypes() { + t.Run(pt.String(), func(t *testing.T) { + t.Parallel() + if got, err := chess.ParsePieceType(pt.String()); err != nil || got != pt { + t.Errorf("ParsePieceType(%q) = %v, %v, want %v, nil", pt.String(), got, err, pt) + } + if got, err := chess.ParsePieceTypeFromByte(pt.Bytes()[0]); err != nil || got != pt { + t.Errorf("ParsePieceTypeFromByte(%q) = %v, %v, want %v, nil", pt.Bytes(), got, err, pt) + } + }) + } +} + +func TestParsePieceTypeFromByte(t *testing.T) { + t.Parallel() + valid := []struct { + name string + in byte + want chess.PieceType + }{ + {"lower_k", 'k', chess.King}, + {"lower_q", 'q', chess.Queen}, + {"lower_r", 'r', chess.Rook}, + {"lower_b", 'b', chess.Bishop}, + {"lower_n", 'n', chess.Knight}, + {"lower_p", 'p', chess.Pawn}, + {"upper_K", 'K', chess.King}, + {"upper_Q", 'Q', chess.Queen}, + } + for _, tt := range valid { + t.Run("valid/"+tt.name, func(t *testing.T) { + t.Parallel() + got, err := chess.ParsePieceTypeFromByte(tt.in) + if err != nil { + t.Fatalf("ParsePieceTypeFromByte(%q): %v", tt.in, err) + } + if got != tt.want { + t.Errorf("ParsePieceTypeFromByte(%q) = %v, want %v", tt.in, got, tt.want) + } + }) + } + invalid := []byte{'1', '?', 'x'} + for _, in := range invalid { + t.Run(fmt.Sprintf("invalid/%q", in), func(t *testing.T) { + t.Parallel() + if got, err := chess.ParsePieceTypeFromByte(in); err == nil { + t.Errorf("ParsePieceTypeFromByte(%q) = %v, want error", in, got) + } + }) + } +} + +func TestParsePieceType(t *testing.T) { + t.Parallel() + valid := []struct { + name string + in string + want chess.PieceType + }{ + {"lower_k", "k", chess.King}, + {"upper_K", "K", chess.King}, + {"upper_Q", "Q", chess.Queen}, + {"upper_N", "N", chess.Knight}, + } + for _, tt := range valid { + t.Run("valid/"+tt.name, func(t *testing.T) { + t.Parallel() + got, err := chess.ParsePieceType(tt.in) + if err != nil { + t.Fatalf("ParsePieceType(%q): %v", tt.in, err) + } + if got != tt.want { + t.Errorf("ParsePieceType(%q) = %v, want %v", tt.in, got, tt.want) + } + }) + } + invalid := []string{"", "kk", "?"} + for _, in := range invalid { + t.Run("invalid/"+in, func(t *testing.T) { + t.Parallel() + if got, err := chess.ParsePieceType(in); err == nil { + t.Errorf("ParsePieceType(%q) = %v, want error", in, got) + } + }) + } +} + +func TestPieceTypes_ReturnsSixTypesInCanonicalOrder(t *testing.T) { + want := [6]chess.PieceType{chess.King, chess.Queen, chess.Rook, chess.Bishop, chess.Knight, chess.Pawn} + if got := chess.PieceTypes(); got != want { + t.Errorf("PieceTypes() = %v, want %v", got, want) + } +} + +func TestColor_FENString(t *testing.T) { + tests := []struct { + name string + c chess.Color + want string + }{ + {"white", chess.White, "w"}, + {"black", chess.Black, "b"}, + {"none", chess.NoColor, "-"}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + if got := tt.c.String(); got != tt.want { + t.Errorf("String() = %q, want %q", got, tt.want) + } + }) + } +} + +func TestColor_Name(t *testing.T) { + tests := []struct { + name string + c chess.Color + want string }{ - {King, "k"}, - {Queen, "q"}, - {Rook, "r"}, - {Bishop, "b"}, - {Knight, "n"}, - {Pawn, "p"}, + {"white", chess.White, "White"}, + {"black", chess.Black, "Black"}, + {"none", chess.NoColor, "No Color"}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + if got := tt.c.Name(); got != tt.want { + t.Errorf("Name() = %q, want %q", got, tt.want) + } + }) } +} - for _, table := range tables { - if table.piece.String() != table.str { - t.Errorf("String version of piece was incorrect.") - } +func TestColor_Other(t *testing.T) { + tests := []struct { + name string + c chess.Color + want chess.Color + }{ + {"white_reverses_to_black", chess.White, chess.Black}, + {"black_reverses_to_white", chess.Black, chess.White}, + {"none_stays_none", chess.NoColor, chess.NoColor}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + if got := tt.c.Other(); got != tt.want { + t.Errorf("Other() = %v, want %v", got, tt.want) + } + }) + } +} + +func TestParseColor(t *testing.T) { + valid := []struct { + name string + in string + want chess.Color + }{ + {"lower_w", "w", chess.White}, + {"lower_b", "b", chess.Black}, + {"upper_W", "W", chess.White}, + {"upper_B", "B", chess.Black}, + } + for _, tt := range valid { + t.Run("valid/"+tt.name, func(t *testing.T) { + got, err := chess.ParseColor(tt.in) + if err != nil { + t.Fatalf("ParseColor(%q): %v", tt.in, err) + } + if got != tt.want { + t.Errorf("ParseColor(%q) = %v, want %v", tt.in, got, tt.want) + } + }) + } + invalid := []string{"x", ""} + for _, in := range invalid { + t.Run("invalid/"+in, func(t *testing.T) { + if got, err := chess.ParseColor(in); err == nil { + t.Errorf("ParseColor(%q) = %v, want error", in, got) + } + }) } } -func TestBytesForPieceTypes(t *testing.T) { +func TestPiece_TypeColorAndConstruction(t *testing.T) { tests := []struct { - pieceType PieceType - expected []byte + name string + piece chess.Piece + pt chess.PieceType + c chess.Color }{ - {King, []byte{'k'}}, - {Queen, []byte{'q'}}, - {Rook, []byte{'r'}}, - {Bishop, []byte{'b'}}, - {Knight, []byte{'n'}}, - {Pawn, []byte{'p'}}, - {NoPieceType, []byte{}}, + {"white_king", chess.WhiteKing, chess.King, chess.White}, + {"white_queen", chess.WhiteQueen, chess.Queen, chess.White}, + {"white_rook", chess.WhiteRook, chess.Rook, chess.White}, + {"white_bishop", chess.WhiteBishop, chess.Bishop, chess.White}, + {"white_knight", chess.WhiteKnight, chess.Knight, chess.White}, + {"white_pawn", chess.WhitePawn, chess.Pawn, chess.White}, + {"black_king", chess.BlackKing, chess.King, chess.Black}, + {"black_queen", chess.BlackQueen, chess.Queen, chess.Black}, + {"black_rook", chess.BlackRook, chess.Rook, chess.Black}, + {"black_bishop", chess.BlackBishop, chess.Bishop, chess.Black}, + {"black_knight", chess.BlackKnight, chess.Knight, chess.Black}, + {"black_pawn", chess.BlackPawn, chess.Pawn, chess.Black}, } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + if got := tt.piece.Type(); got != tt.pt { + t.Errorf("Type() = %v, want %v", got, tt.pt) + } + if got := tt.piece.Color(); got != tt.c { + t.Errorf("Color() = %v, want %v", got, tt.c) + } + if got := chess.NewPiece(tt.pt, tt.c); got != tt.piece { + t.Errorf("NewPiece(%v,%v) = %v, want %v", tt.pt, tt.c, got, tt.piece) + } + }) + } +} + +func TestPiece_StringAndDarkString(t *testing.T) { + tests := []struct { + name string + piece chess.Piece + str, dark string + }{ + {"white_king", chess.WhiteKing, "♔", "♚"}, + {"white_queen", chess.WhiteQueen, "♕", "♛"}, + {"white_rook", chess.WhiteRook, "♖", "♜"}, + {"white_bishop", chess.WhiteBishop, "♗", "♝"}, + {"white_knight", chess.WhiteKnight, "♘", "♞"}, + {"white_pawn", chess.WhitePawn, "♙", "♟"}, + {"black_king", chess.BlackKing, "♚", "♔"}, + {"black_queen", chess.BlackQueen, "♛", "♕"}, + {"black_rook", chess.BlackRook, "♜", "♖"}, + {"black_bishop", chess.BlackBishop, "♝", "♗"}, + {"black_knight", chess.BlackKnight, "♞", "♘"}, + {"black_pawn", chess.BlackPawn, "♟", "♙"}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + if got := tt.piece.String(); got != tt.str { + t.Errorf("String() = %q, want %q", got, tt.str) + } + if got := tt.piece.DarkString(); got != tt.dark { + t.Errorf("DarkString() = %q, want %q", got, tt.dark) + } + }) + } +} + +func TestPiece_DarkStringReversesColors(t *testing.T) { + for _, pt := range chess.PieceTypes() { + t.Run(pt.String(), func(t *testing.T) { + white := chess.NewPiece(pt, chess.White) + black := chess.NewPiece(pt, chess.Black) + if white.DarkString() != black.String() { + t.Errorf("white DarkString() = %q, want black String() = %q", white.DarkString(), black.String()) + } + if white.String() != black.DarkString() { + t.Errorf("white String() = %q, want black DarkString() = %q", white.String(), black.DarkString()) + } + }) + } +} + +func TestNoPiece_IsEmptySentinel(t *testing.T) { + if got := chess.NoPiece.String(); got != "-" { + t.Errorf("NoPiece.String() = %q, want %q", got, "-") + } + if got := chess.NoPiece.Type(); got != chess.NoPieceType { + t.Errorf("NoPiece.Type() = %v, want %v", got, chess.NoPieceType) + } + if got := chess.NoPiece.Color(); got != chess.NoColor { + t.Errorf("NoPiece.Color() = %v, want %v", got, chess.NoColor) + } +} +func TestNewPiece_ReturnsNoPieceForInvalidInputs(t *testing.T) { + tests := []struct { + name string + pt chess.PieceType + c chess.Color + }{ + {"invalid_type", chess.NoPieceType, chess.White}, + {"invalid_color", chess.King, chess.NoColor}, + } for _, tt := range tests { - if !bytes.Equal(tt.pieceType.Bytes(), tt.expected) { - t.Fatalf("expected %v but got %v", tt.expected, tt.pieceType.Bytes()) - } + t.Run(tt.name, func(t *testing.T) { + if got := chess.NewPiece(tt.pt, tt.c); got != chess.NoPiece { + t.Errorf("NewPiece(%v,%v) = %v, want NoPiece", tt.pt, tt.c, got) + } + }) } } diff --git a/polyglot.go b/polyglot.go index 3a52d1b3..ba3670d3 100644 --- a/polyglot.go +++ b/polyglot.go @@ -1,12 +1,12 @@ package chess import ( - "bytes" - "crypto/rand" + "cmp" "encoding/binary" "errors" - "fmt" "io" + "math/rand/v2" + "slices" "sort" ) @@ -23,7 +23,7 @@ type PolyglotEntry struct { // PolyglotMove represents a decoded chess move from a polyglot entry. // The coordinates use 0-based indices where: // - Files go from 0 (a-file) to 7 (h-file) -// - Ranks go from 0 (1st rank) to 7 (8th rank) +// - Ranks go from 0 (1st rank) to 7 (8th rank). type PolyglotMove struct { FromFile int // Source file (0-7) FromRank int // Source rank (0-7) @@ -50,7 +50,7 @@ type PolyglotMove struct { // moves := book.FindMoves(hash) // // // Get a random move weighted by the stored weights -// randomMove := book.GetRandomMove(hash) +// randomMove := book.RandomMove(hash) type PolyglotBook struct { entries []PolyglotEntry } @@ -112,152 +112,20 @@ func (pm PolyglotMove) ToMove() Move { moveStr = string(moveBuf[:4]) } - decode, err := UCINotation{}.Decode(nil, moveStr) + decode, err := uciNotation{}.Decode(nil, moveStr) if err != nil { return Move{} } if pm.CastlingMove { if pm.FromFile == 4 && (pm.ToFile == 0 || pm.ToFile == 2) { - decode.AddTag(QueenSideCastle) + decode = decode.WithTag(QueenSideCastle) } else { - decode.AddTag(KingSideCastle) + decode = decode.WithTag(KingSideCastle) } } - return *decode -} - -// BookSource defines the interface for reading polyglot book data. -// This interface allows for different source implementations (file, memory, etc.) -// while maintaining consistent access patterns. -type BookSource interface { - // Read reads exactly len(p) bytes into p or returns an error - Read(p []byte) (n int, err error) - // Size returns the total size of the book data - Size() (int64, error) -} - -// ReaderBookSource implements BookSource for io.Reader -type ReaderBookSource struct { - reader io.Reader - data []byte // Buffered data for Size() implementation - readIndex int64 -} - -// NewReaderBookSource creates a new reader-based book source -// Note: This will read the entire input into memory to support Size() and multiple reads -func NewReaderBookSource(reader io.Reader) (*ReaderBookSource, error) { - // Read all data into memory - data, err := io.ReadAll(reader) - if err != nil { - return nil, err - } - - return &ReaderBookSource{ - reader: bytes.NewReader(data), - data: data, - readIndex: 0, - }, nil -} - -// Read implements BookSource for ReaderBookSource -func (r *ReaderBookSource) Read(p []byte) (n int, err error) { - if r.readIndex >= int64(len(r.data)) { - return 0, io.EOF - } - - n = copy(p, r.data[r.readIndex:]) - r.readIndex += int64(n) - - if n < len(p) { - return n, io.EOF - } - return n, nil -} - -// Size implements BookSource for ReaderBookSource -func (r *ReaderBookSource) Size() (int64, error) { - return int64(len(r.data)), nil -} - -// FileBookSource implements BookSource for files -type FileBookSource struct { - path string -} - -// BytesBookSource implements BookSource for byte slices -type BytesBookSource struct { - data []byte - index int64 -} - -// NewBytesBookSource creates a new memory-based book source -func NewBytesBookSource(data []byte) *BytesBookSource { - return &BytesBookSource{ - data: data, - index: 0, - } -} - -// Read implements BookSource for BytesBookSource -func (b *BytesBookSource) Read(p []byte) (n int, err error) { - if b.index >= int64(len(b.data)) { - return 0, io.EOF - } - - n = copy(p, b.data[b.index:]) - b.index += int64(n) - - if n < len(p) { - return n, io.EOF - } - return n, nil -} - -// Size implements BookSource for BytesBookSource -func (b *BytesBookSource) Size() (int64, error) { - return int64(len(b.data)), nil -} - -// LoadFromSource loads a polyglot book from any BookSource -func LoadFromSource(source BookSource) (*PolyglotBook, error) { - size, err := source.Size() - if err != nil { - return nil, err - } - - if size%16 != 0 { - return nil, errors.New("invalid polyglot book data size") - } - - numEntries := size / 16 - entries := make([]PolyglotEntry, 0, numEntries) - - buf := make([]byte, 16) - for { - _, readErr := source.Read(buf) - if readErr == io.EOF { - break - } - if readErr != nil { - return nil, readErr - } - - entry := PolyglotEntry{ - Key: binary.BigEndian.Uint64(buf[0:8]), - Move: binary.BigEndian.Uint16(buf[8:10]), - Weight: binary.BigEndian.Uint16(buf[10:12]), - Learn: binary.BigEndian.Uint32(buf[12:16]), - } - entries = append(entries, entry) - } - - sort.Slice(entries, func(i, j int) bool { - return entries[i].Key < entries[j].Key - }) - - return &PolyglotBook{entries: entries}, nil + return decode } // LoadFromReader loads a polyglot book from an io.Reader. @@ -276,11 +144,11 @@ func LoadFromSource(source BookSource) (*PolyglotBook, error) { // log.Fatal(err) // } func LoadFromReader(reader io.Reader) (*PolyglotBook, error) { - source, err := NewReaderBookSource(reader) + data, err := io.ReadAll(reader) if err != nil { return nil, err } - return LoadFromSource(source) + return parseBookData(data) } // LoadFromBytes loads a polyglot book from a byte slice. @@ -294,8 +162,32 @@ func LoadFromReader(reader io.Reader) (*PolyglotBook, error) { // log.Fatal(err) // } func LoadFromBytes(data []byte) (*PolyglotBook, error) { - source := NewBytesBookSource(data) - return LoadFromSource(source) + return parseBookData(data) +} + +// ponytail: parseBookData is the single entry for both readers and bytes — +// one shape per loader, no BookSource adapter layer. Add a streaming loader +// here if a future caller needs to feed a polyglot book without buffering. +func parseBookData(data []byte) (*PolyglotBook, error) { + if len(data)%16 != 0 { + return nil, errors.New("chess: invalid polyglot book data size") + } + + entries := make([]PolyglotEntry, 0, len(data)/16) + for i := 0; i < len(data); i += 16 { + entries = append(entries, PolyglotEntry{ + Key: binary.BigEndian.Uint64(data[i : i+8]), + Move: binary.BigEndian.Uint16(data[i+8 : i+10]), + Weight: binary.BigEndian.Uint16(data[i+10 : i+12]), + Learn: binary.BigEndian.Uint32(data[i+12 : i+16]), + }) + } + + slices.SortFunc(entries, func(a, b PolyglotEntry) int { + return cmp.Compare(a.Key, b.Key) + }) + + return &PolyglotBook{entries: entries}, nil } // FindMoves looks up all moves for a given position hash. @@ -326,8 +218,8 @@ func (book *PolyglotBook) FindMoves(positionHash uint64) []PolyglotEntry { moves = append(moves, book.entries[i]) } - sort.Slice(moves, func(i, j int) bool { - return moves[i].Weight > moves[j].Weight + slices.SortFunc(moves, func(a, b PolyglotEntry) int { + return cmp.Compare(b.Weight, a.Weight) }) return moves @@ -366,20 +258,20 @@ func DecodeMove(move uint16) PolyglotMove { } } -// Helper function to identify castling moves +// Helper function to identify castling moves. func isCastlingMove(fromFile, fromRank, toFile, toRank int) bool { return fromFile == 4 && (fromRank == 0 || fromRank == 7) && (toFile == 0 || toFile == 7) && toRank == fromRank } -// GetRandomMove returns a weighted random move from the available moves for a position. +// RandomMove returns a weighted random move from the available moves for a position. // The probability of selecting a move is proportional to its weight. // Returns nil if no moves are available. // // Example: // // hash := uint64(0x463b96181691fc9c) // Starting position -// move, err := book.GetRandomMove(hash) +// move, err := book.RandomMove(hash) // if err != nil { // log.Fatal(err) // } @@ -387,22 +279,21 @@ func isCastlingMove(fromFile, fromRank, toFile, toRank int) bool { // decodedMove := DecodeMove(move.Move) // fmt.Printf("Selected move: %v\n", decodedMove) // } -func (book *PolyglotBook) GetRandomMove(positionHash uint64) (*PolyglotEntry, error) { +func (book *PolyglotBook) RandomMove(positionHash uint64) (*PolyglotEntry, error) { moves := book.FindMoves(positionHash) if len(moves) == 0 { - return nil, nil + return nil, nil //nolint:nilnil // nil,nil is the documented "no move for this position" signal } totalWeight := 0 for _, move := range moves { totalWeight += int(move.Weight) } - - r, err := fastRand() - if err != nil { - return nil, err + if totalWeight == 0 { + return nil, nil //nolint:nilnil // nil,nil is the documented "no weighted move available" signal } - rn := int(r) % totalWeight + + rn := int(rand.Uint32()) % totalWeight currentWeight := 0 for _, move := range moves { currentWeight += int(move.Weight) @@ -414,16 +305,12 @@ func (book *PolyglotBook) GetRandomMove(positionHash uint64) (*PolyglotEntry, er return &moves[0], nil } -// fastRand returns a cryptographically secure random uint32. -// This implementation uses crypto/rand instead of math/rand to ensure -// that move selection cannot be predicted or manipulated. -func fastRand() (uint32, error) { - b := make([]byte, 4) - _, err := rand.Read(b) - if err != nil { - return 0, fmt.Errorf("failed to generate random number: %w", err) - } - return binary.BigEndian.Uint32(b), nil +// fastRand returns a pseudorandom uint32 from math/rand/v2. The package-level +// source is automatically seeded, so callers do not need to seed it. Note that +// this is no longer cryptographically secure; opening book selection is for +// casual play and does not require cryptographic randomness. +func fastRand() uint32 { + return rand.Uint32() } // NewPolyglotBookFromMap creates a PolyglotBook from a map where @@ -441,8 +328,8 @@ func NewPolyglotBookFromMap(m map[uint64][]MoveWithWeight) *PolyglotBook { entries = append(entries, entry) } } - sort.Slice(entries, func(i, j int) bool { - return entries[i].Key < entries[j].Key + slices.SortFunc(entries, func(a, b PolyglotEntry) int { + return cmp.Compare(a.Key, b.Key) }) return &PolyglotBook{entries: entries} } @@ -457,8 +344,8 @@ func (book *PolyglotBook) AddMove(positionHash uint64, move Move, weight uint16) } book.entries = append(book.entries, entry) // Re-sort after adding - sort.Slice(book.entries, func(i, j int) bool { - return book.entries[i].Key < book.entries[j].Key + slices.SortFunc(book.entries, func(a, b PolyglotEntry) int { + return cmp.Compare(a.Key, b.Key) }) } @@ -473,7 +360,7 @@ func (book *PolyglotBook) UpdateMove(positionHash uint64, move Move, newWeight u } } if !updated { - return errors.New("move not found for update") + return errors.New("chess: move not found for update") } return nil } @@ -489,10 +376,10 @@ func (book *PolyglotBook) DeleteMoves(positionHash uint64) { book.entries = newEntries } -func (book *PolyglotBook) GetChessMoves(positionHash uint64) ([]Move, error) { +func (book *PolyglotBook) ChessMoves(positionHash uint64) ([]Move, error) { entries := book.FindMoves(positionHash) if entries == nil { - return nil, errors.New("no moves found for the given position") + return nil, errors.New("chess: no moves found for the given position") } var moves []Move for _, entry := range entries { diff --git a/polyglot_test.go b/polyglot_test.go index e3f6d917..26c2b2e9 100644 --- a/polyglot_test.go +++ b/polyglot_test.go @@ -3,10 +3,6 @@ package chess import ( "bytes" "encoding/binary" - "errors" - "io" - "os" - "path/filepath" "reflect" "testing" ) @@ -30,117 +26,44 @@ func createTestBook(entries []PolyglotEntry) []byte { return buf.Bytes() } -func TestBytesBookSource(t *testing.T) { +func TestLoadFromBytes(t *testing.T) { + // Unsorted on purpose: parser must sort by Key. testEntries := []PolyglotEntry{ - {Key: 1, Move: 100, Weight: 10, Learn: 0}, {Key: 2, Move: 200, Weight: 20, Learn: 0}, - } - bookData := createTestBook(testEntries) - - source := NewBytesBookSource(bookData) - - // Test Size - size, err := source.Size() - if err != nil { - t.Errorf("Size() error = %v", err) - } - if size != 32 { // 2 entries * 16 bytes - t.Errorf("Size() = %v, want %v", size, 32) - } - - // Test Read - buf := make([]byte, 16) - n, err := source.Read(buf) - if err != nil { - t.Errorf("Read() error = %v", err) - } - if n != 16 { - t.Errorf("Read() = %v bytes, want %v", n, 16) - } - - // Test EOF - source.index = 32 - _, err = source.Read(buf) - if !errors.Is(err, io.EOF) { - t.Errorf("Read() error = %v, want EOF", err) - } -} - -func TestReaderBookSource(t *testing.T) { - testEntries := []PolyglotEntry{ {Key: 1, Move: 100, Weight: 10, Learn: 0}, - {Key: 2, Move: 200, Weight: 20, Learn: 0}, } bookData := createTestBook(testEntries) - reader := bytes.NewReader(bookData) - source, err := NewReaderBookSource(reader) + book, err := LoadFromBytes(bookData) if err != nil { - t.Fatalf("NewReaderBookSource() error = %v", err) + t.Fatalf("LoadFromBytes() error = %v", err) } - size, err := source.Size() - if err != nil || size != 32 { - t.Errorf("Size() = %v, %v, want 32, nil", size, err) + if len(book.entries) != 2 { + t.Fatalf("LoadFromBytes() loaded %v entries, want 2", len(book.entries)) } - - buf := make([]byte, 16) - n, err := source.Read(buf) - if err != nil || n != 16 { - t.Errorf("Read() = %v, %v, want 16, nil", n, err) + if book.entries[0].Key != 1 || book.entries[1].Key != 2 { + t.Error("LoadFromBytes() entries not sorted by Key") } } -func TestFileBookSource(t *testing.T) { - // Create temporary test file +func TestLoadFromReader(t *testing.T) { testEntries := []PolyglotEntry{ {Key: 1, Move: 100, Weight: 10, Learn: 0}, {Key: 2, Move: 200, Weight: 20, Learn: 0}, } bookData := createTestBook(testEntries) - tmpDir := t.TempDir() - tmpFile := filepath.Join(tmpDir, "test.bin") - if err := os.WriteFile(tmpFile, bookData, 0o666); err != nil { - t.Fatalf("Failed to create test file: %v", err) - } - - osFile, _ := os.Open(tmpFile) - - source, _ := NewReaderBookSource(osFile) - - size, err := source.Size() - if err != nil || size != 32 { - t.Errorf("Size() = %v, %v, want 32, nil", size, err) - } - - buf := make([]byte, 16) - n, err := source.Read(buf) - if err != nil || n != 16 { - t.Errorf("Read() = %v, %v, want 16, nil", n, err) - } -} - -func TestLoadFromSource(t *testing.T) { - testEntries := []PolyglotEntry{ - {Key: 2, Move: 200, Weight: 20, Learn: 0}, // Intentionally unsorted - {Key: 1, Move: 100, Weight: 10, Learn: 0}, - } - bookData := createTestBook(testEntries) - source := NewBytesBookSource(bookData) - - book, err := LoadFromSource(source) + book, err := LoadFromReader(bytes.NewReader(bookData)) if err != nil { - t.Fatalf("LoadFromSource() error = %v", err) + t.Fatalf("LoadFromReader() error = %v", err) } if len(book.entries) != 2 { - t.Errorf("LoadFromSource() loaded %v entries, want 2", len(book.entries)) + t.Fatalf("LoadFromReader() loaded %v entries, want 2", len(book.entries)) } - - // Verify entries are sorted if book.entries[0].Key != 1 || book.entries[1].Key != 2 { - t.Error("LoadFromSource() entries not properly sorted") + t.Error("LoadFromReader() entries not sorted by Key") } } @@ -240,7 +163,7 @@ func TestDecodeMove(t *testing.T) { } } -func TestGetRandomMove(t *testing.T) { +func TestRandomMove(t *testing.T) { book := &PolyglotBook{ entries: []PolyglotEntry{ {Key: 1, Move: 100, Weight: 10, Learn: 0}, @@ -249,21 +172,38 @@ func TestGetRandomMove(t *testing.T) { } // Test with existing position - move, err := book.GetRandomMove(1) + move, err := book.RandomMove(1) if err != nil { - t.Fatalf("GetRandomMove() error = %v", err) + t.Fatalf("RandomMove() error = %v", err) } if move == nil { - t.Error("GetRandomMove() returned nil for existing position") + t.Error("RandomMove() returned nil for existing position") } // Test with non-existing position - move, err = book.GetRandomMove(999) + move, err = book.RandomMove(999) + if err != nil { + t.Fatalf("RandomMove() error = %v", err) + } + if move != nil { + t.Error("RandomMove() returned move for non-existing position") + } +} + +func TestRandomMoveWithZeroTotalWeight(t *testing.T) { + book := &PolyglotBook{ + entries: []PolyglotEntry{ + {Key: 1, Move: 100, Weight: 0, Learn: 0}, + {Key: 1, Move: 101, Weight: 0, Learn: 0}, + }, + } + + move, err := book.RandomMove(1) if err != nil { - t.Fatalf("GetRandomMove() error = %v", err) + t.Fatalf("RandomMove() error = %v", err) } if move != nil { - t.Error("GetRandomMove() returned move for non-existing position") + t.Fatalf("RandomMove() = %v, want nil", move) } } @@ -663,7 +603,7 @@ func TestDeleteMoves(t *testing.T) { } } -func TestGetChessMoves(t *testing.T) { +func TestChessMoves(t *testing.T) { pos := uint64(50) move1 := Move{ s1: D2, @@ -681,9 +621,9 @@ func TestGetChessMoves(t *testing.T) { {Key: pos, Move: MoveToPolyglot(move2), Weight: 220, Learn: 0}, }, } - moves, err := book.GetChessMoves(pos) + moves, err := book.ChessMoves(pos) if err != nil { - t.Fatalf("GetChessMoves returned error: %v", err) + t.Fatalf("ChessMoves returned error: %v", err) } if len(moves) != 2 { t.Fatalf("Expected 2 moves, got %d", len(moves)) @@ -698,7 +638,7 @@ func TestGetChessMoves(t *testing.T) { } // Test error case: request moves for a non-existent position. - _, err = book.GetChessMoves(999) + _, err = book.ChessMoves(999) if err == nil { t.Errorf("Expected error for non-existent position, got nil") } @@ -778,7 +718,21 @@ func BenchmarkToMoveMap(b *testing.B) { b.ReportAllocs() - for i := 0; i < b.N; i++ { + for range b.N { _ = book.ToMoveMap() } } + +func TestFastRandDistribution(t *testing.T) { + // fastRand now wraps math/rand/v2.Uint32. We don't test randomness + // quality (that's the std lib's job), just that the helper returns + // a uint32 without panicking and produces varying values. + seen := make(map[uint32]struct{}, 32) + for range 32 { + v := fastRand() + seen[v] = struct{}{} + } + if len(seen) < 16 { + t.Errorf("fastRand produced too few distinct values: %d/32", len(seen)) + } +} diff --git a/position.go b/position.go index 55afad55..c59941ed 100644 --- a/position.go +++ b/position.go @@ -1,31 +1,12 @@ -/* -Package chess provides position representation and manipulation for chess games. -The package implements complete position tracking including piece placement, -castling rights, en passant squares, and move counts. It supports standard chess -formats (FEN) and provides methods for position analysis and move validation. -Example usage: - - // Create starting position - pos := StartingPosition() - - // Check valid moves - moves := pos.ValidMoves() - - // Update position with move - newPos := pos.Update(move) - - // Get FEN string - fen := pos.String() -*/ package chess import ( "bytes" - "crypto/md5" "encoding/binary" "errors" "fmt" - "strings" + "strconv" + "sync" ) // Side represents a side of the board. @@ -38,8 +19,27 @@ const ( QueenSide ) +// castleSideRights holds the castling rights for one side. +type castleSideRights struct { + KingSide bool + QueenSide bool +} + // CastleRights holds the state of both sides castling abilities. -type CastleRights string +type CastleRights struct { + White castleSideRights + Black castleSideRights +} + +// NewCastleRights returns a CastleRights value with the four per-color, +// per-side flags set explicitly. It is the supported way for callers outside +// this package to construct a CastleRights value. +func NewCastleRights(whiteKingSide, whiteQueenSide, blackKingSide, blackQueenSide bool) CastleRights { + return CastleRights{ + White: castleSideRights{KingSide: whiteKingSide, QueenSide: whiteQueenSide}, + Black: castleSideRights{KingSide: blackKingSide, QueenSide: blackQueenSide}, + } +} // CanCastle returns true if the given color and side combination can castle. // @@ -49,27 +49,74 @@ type CastleRights string // // White can castle kingside // } func (cr CastleRights) CanCastle(c Color, side Side) bool { - char := "k" - if side == QueenSide { - char = "q" - } - if c == White { - char = strings.ToUpper(char) + switch c { + case White: + switch side { + case KingSide: + return cr.White.KingSide + case QueenSide: + return cr.White.QueenSide + } + case Black: + switch side { + case KingSide: + return cr.Black.KingSide + case QueenSide: + return cr.Black.QueenSide + } } - return strings.Contains(string(cr), char) + return false } -// String implements the fmt.Stringer interface and returns -// a FEN compatible string. Ex. KQq. +// String implements the fmt.Stringer interface and returns a FEN compatible +// string in canonical order (KQkq), or "-" when no side can castle. func (cr CastleRights) String() string { - return string(cr) + var b [4]byte + n := 0 + if cr.White.KingSide { + b[n] = 'K' + n++ + } + if cr.White.QueenSide { + b[n] = 'Q' + n++ + } + if cr.Black.KingSide { + b[n] = 'k' + n++ + } + if cr.Black.QueenSide { + b[n] = 'q' + n++ + } + if n == 0 { + return "-" + } + return string(b[:n]) +} + +// MarshalText implements the encoding.TextMarshaler interface using the FEN +// representation. +func (cr CastleRights) MarshalText() ([]byte, error) { + return []byte(cr.String()), nil +} + +// UnmarshalText implements the encoding.TextUnmarshaler interface using the FEN +// representation. +func (cr *CastleRights) UnmarshalText(text []byte) error { + rights, err := formCastleRights(string(text)) + if err != nil { + return err + } + *cr = rights + return nil } // Position represents a complete chess position state. // It includes piece placement, castling rights, en passant squares, // move counts, and side to move. type Position struct { - board *Board // Current board state + board Board // Current board state castleRights CastleRights // Available castling options validMoves []Move // Cache of legal moves halfMoveClock int // Half-move counter @@ -77,18 +124,55 @@ type Position struct { turn Color // Side to move enPassantSquare Square // En passant target square inCheck bool // Whether current side is in check + checkers bitboard // Bitboard of pieces giving check (zero when not in check) hash uint64 // Zobrist hash for O(1) position comparison + status Method // Cached Status result + statusCached bool // Whether status contains a valid cached value + variant Variant // Starting-position variant (zero = Standard) } const ( startFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" // Starting position FEN ) +var ( + startingPositionOnce sync.Once + startingPosition Position +) + // StartingPosition returns the starting position // rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1. func StartingPosition() *Position { - pos, _ := decodeFEN(startFEN) - return pos + startingPositionOnce.Do(func() { + pos, err := decodeFEN(startFEN) + if err != nil { + panic(err) + } + startingPosition = *pos + }) + return startingPosition.copy() +} + +// AnyLegalMove reports whether the position has at least one legal move. +func (pos *Position) AnyLegalMove() bool { + return hasLegalMove(pos) +} + +// IsLegal reports whether m is a legal move in the current position. It +// returns false for null moves and for moves whose origin square belongs to +// the side not to move. The check is a linear scan of the legal move list; +// callers who need the canonical Move with position-derived tags should use +// Game.Move or resolveCanonicalMove. +func (pos *Position) IsLegal(m Move) bool { + if pos == nil || m.HasTag(Null) { + return false + } + for _, valid := range pos.ValidMovesUnsafe() { + if valid.s1 == m.s1 && valid.s2 == m.s2 && valid.promo == m.promo { + return true + } + } + return false } // Update returns a new position resulting from the given move. @@ -99,141 +183,98 @@ func StartingPosition() *Position { // Example: // // newPos := pos.Update(move) -func (pos *Position) Update(m *Move) *Position { - moveCount := pos.moveCount - if pos.turn == Black { - moveCount++ - } - - if m == nil { - newPos := &Position{ - board: pos.board.copy(), - turn: pos.turn.Other(), - castleRights: pos.castleRights, - enPassantSquare: NoSquare, - halfMoveClock: pos.halfMoveClock + 1, - moveCount: moveCount, - inCheck: false, - } - newPos.hash = newPos.computeHash() - return newPos - } - - ncr := pos.updateCastleRights(m) - p := pos.board.Piece(m.s1) - halfMove := pos.halfMoveClock - if p.Type() == Pawn || m.HasTag(Capture) { - halfMove = 0 - } else { - halfMove++ - } - b := pos.board.copy() - b.update(m) +func (pos *Position) Update(m Move) *Position { + // Null moves flip the side to move without touching the board. + if m.HasTag(Null) { + return pos.nullUpdate() + } + + // Seed a fresh position with the pre-move scalars (including the pre-move + // hash) so applyMove can mutate it in one place. applyMove overwrites + // every field it owns — board, hash, turn, castleRights, enPassantSquare, + // halfMoveClock, moveCount — and reads the seed for the pre-move state + // that updateCastleRights, updateEnPassantSquare, and updateHash need + // before overwriting. newPos := &Position{ - board: b, - turn: pos.turn.Other(), - castleRights: ncr, - enPassantSquare: pos.updateEnPassantSquare(m), - halfMoveClock: halfMove, - moveCount: moveCount, - inCheck: m.HasTag(Check), - } - newPos.hash = pos.updateHash(m, ncr, newPos.enPassantSquare) + board: pos.board, + turn: pos.turn, + castleRights: pos.castleRights, + enPassantSquare: pos.enPassantSquare, + halfMoveClock: pos.halfMoveClock, + moveCount: pos.moveCount, + variant: pos.variant, + hash: pos.hash, + } + newPos.applyMove(m) return newPos } -// updateHash computes the new Zobrist hash incrementally from a move. -func (pos *Position) updateHash(m *Move, newCR CastleRights, newEP Square) uint64 { +// updateHash computes the new Zobrist hash incrementally from a move. It +// consumes the moveEffect that drove the board mutation so the hash delta and +// the board read one interpretation of the move's physical facts (en-passant +// square, castle rook squares, capture target) instead of each re-reading +// MoveTags and risking drift. +// +// newCR and newEP are the post-move castling rights and en-passant target +// square — these are bookkeeping rules that live in their own helpers +// (updateCastleRights, updateEnPassantSquare), not in moveEffect, so they are +// passed in alongside. +func (pos *Position) updateHash(m Move, newCR CastleRights, newEP Square, eff moveEffect) uint64 { hash := pos.hash // Toggle side to move hash ^= polyglotHashesUint64[780] - // XOR out piece from origin square - p := pos.board.Piece(m.s1) - oldIdx := pieceZobristIndex(p, m.s1) + // XOR out moving piece from origin square + oldIdx := pieceZobristIndex(eff.moving, m.s1) if oldIdx >= 0 { hash ^= polyglotHashesUint64[oldIdx] } - // Determine what piece ends up at destination - var destPiece Piece - if m.promo != NoPieceType { - destPiece = NewPiece(m.promo, pos.turn) - } else { - destPiece = p - } - destIdx := pieceZobristIndex(destPiece, m.s2) + // XOR in landing piece at destination (a promotion piece when eff.landing != eff.moving) + destIdx := pieceZobristIndex(eff.landing, m.s2) if destIdx >= 0 { hash ^= polyglotHashesUint64[destIdx] } - // Handle captures (including en passant) - if m.HasTag(Capture) { - captured := pos.board.Piece(m.s2) - if captured != NoPiece { - capIdx := pieceZobristIndex(captured, m.s2) - if capIdx >= 0 { - hash ^= polyglotHashesUint64[capIdx] - } - } - } - if m.HasTag(EnPassant) { - // Captured pawn is adjacent to destination, not on destination - var capturedSq Square - if pos.turn == White { - capturedSq = m.s2 - 8 - } else { - capturedSq = m.s2 + 8 - } - captured := pos.board.Piece(capturedSq) - capIdx := pieceZobristIndex(captured, capturedSq) + // XOR out captured piece at its square. Normal capture and en passant + // share one branch: moveEffect already resolved the en-passant square to + // s2±8 when applicable. + if eff.capPiece != NoPiece { + capIdx := pieceZobristIndex(eff.capPiece, eff.capSq) if capIdx >= 0 { hash ^= polyglotHashesUint64[capIdx] } } - // Handle castling rook moves - if m.HasTag(KingSideCastle) { - if pos.turn == White { - hash ^= polyglotHashesUint64[pieceZobristIndex(WhiteRook, H1)] - hash ^= polyglotHashesUint64[pieceZobristIndex(WhiteRook, F1)] - } else { - hash ^= polyglotHashesUint64[pieceZobristIndex(BlackRook, H8)] - hash ^= polyglotHashesUint64[pieceZobristIndex(BlackRook, F8)] - } - } else if m.HasTag(QueenSideCastle) { - if pos.turn == White { - hash ^= polyglotHashesUint64[pieceZobristIndex(WhiteRook, A1)] - hash ^= polyglotHashesUint64[pieceZobristIndex(WhiteRook, D1)] - } else { - hash ^= polyglotHashesUint64[pieceZobristIndex(BlackRook, A8)] - hash ^= polyglotHashesUint64[pieceZobristIndex(BlackRook, D8)] - } + // XOR the castle rook between its origin and destination. The rook piece + // is always the moving side's rook; moveEffect carries the squares. + if eff.rookFrom != NoSquare { + rook := NewPiece(Rook, eff.moving.Color()) + hash ^= polyglotHashesUint64[pieceZobristIndex(rook, eff.rookFrom)] + hash ^= polyglotHashesUint64[pieceZobristIndex(rook, eff.rookTo)] } // Update castling rights: XOR out removed rights - oldCR := pos.castleRights.String() - newCRStr := newCR.String() - if strings.Contains(oldCR, "K") && !strings.Contains(newCRStr, "K") { + if pos.castleRights.CanCastle(White, KingSide) && !newCR.CanCastle(White, KingSide) { hash ^= polyglotHashesUint64[768] } - if strings.Contains(oldCR, "Q") && !strings.Contains(newCRStr, "Q") { + if pos.castleRights.CanCastle(White, QueenSide) && !newCR.CanCastle(White, QueenSide) { hash ^= polyglotHashesUint64[769] } - if strings.Contains(oldCR, "k") && !strings.Contains(newCRStr, "k") { + if pos.castleRights.CanCastle(Black, KingSide) && !newCR.CanCastle(Black, KingSide) { hash ^= polyglotHashesUint64[770] } - if strings.Contains(oldCR, "q") && !strings.Contains(newCRStr, "q") { + if pos.castleRights.CanCastle(Black, QueenSide) && !newCR.CanCastle(Black, QueenSide) { hash ^= polyglotHashesUint64[771] } // Update en passant: XOR out old if present - if oldEPFile := enPassantFileForHash(pos.board, pos.enPassantSquare); oldEPFile >= 0 { + if oldEPFile := enPassantFileForHash(&pos.board, pos.enPassantSquare); oldEPFile >= 0 { hash ^= polyglotHashesUint64[772+oldEPFile] } // XOR in new if present - if newEPFile := enPassantFileForHash(pos.board, newEP); newEPFile >= 0 { + if newEPFile := enPassantFileForHash(&pos.board, newEP); newEPFile >= 0 { hash ^= polyglotHashesUint64[772+newEPFile] } @@ -247,7 +288,7 @@ func (pos *Position) ValidMoves() []Move { if pos.validMoves != nil { return append([]Move(nil), pos.validMoves...) } - pos.validMoves = engine{}.CalcMoves(pos, false) + pos.validMoves = calcMoves(pos, false) return append([]Move(nil), pos.validMoves...) } @@ -258,10 +299,18 @@ func (pos *Position) ValidMovesUnsafe() []Move { if pos.validMoves != nil { return pos.validMoves } - pos.validMoves = engine{}.CalcMoves(pos, false) + pos.validMoves = calcMoves(pos, false) return pos.validMoves } +// LegalMovesFast returns legal moves in the same stable generation order as +// ValidMovesUnsafe without computing display-only check annotations. The +// returned moves remain valid inputs to Position.Update. This is intended for +// replay/index codecs that need move identity and legality but not SAN tags. +func (pos *Position) LegalMovesFast() []Move { + return legalMovesForMode(pos, generateLegalOnly) +} + // ValidMovesIter yields all legal moves in the current position. // It uses Go 1.23's range-over-func pattern for zero-allocation iteration // once the move cache is warm. The first call may allocate if moves have @@ -284,18 +333,48 @@ func (pos *Position) ValidMovesIter(yield func(Move) bool) { // UnsafeMoves returns all pseudo-legal moves that are illegal because they leave // the moving side's king in check. These moves should not be played via Move(). func (pos *Position) UnsafeMoves() []Move { - return engine{}.UnsafeMoves(pos) + return unsafeMoves(pos) } -// Status returns the position's status as one of the outcome methods. -// Possible returns values include Checkmate, Stalemate, and NoMethod. +// Status returns the position's outcome Method (e.g. Checkmate, Stalemate, or +// NoMethod). func (pos *Position) Status() Method { - return engine{}.Status(pos) + if pos.statusCached { + return pos.status + } + pos.status = status(pos) + pos.statusCached = true + return pos.status +} + +// Outcome returns the decisive or draw outcome implied by the position, or +// NoOutcome if play continues. It considers board-state terminal conditions +// only: checkmate, stalemate, insufficient material, and the seventy-five +// move rule. Game-level outcomes such as resignation, draw offer, and the +// claimable fifty-move rule are not included and must be queried on Game. +func (pos *Position) Outcome() Outcome { + if pos == nil { + return NoOutcome + } + outcome, _ := classifyOutcome(pos, 0, outcomeRules{includeAutoDraws: true}) + return outcome +} + +// HasInsufficientMaterial reports whether color c cannot force checkmate with +// its remaining material against any opposing material. +func (pos *Position) HasInsufficientMaterial(c Color) bool { + if pos == nil { + return true + } + return pos.board.HasInsufficientMaterial(c) } // Board returns the position's board. func (pos *Position) Board() *Board { - return pos.board + if pos == nil { + return nil + } + return pos.board.copy() } // Turn returns the color to move next. @@ -303,11 +382,34 @@ func (pos *Position) Turn() Color { return pos.turn } -// ChangeTurn returns a new position with the turn changed. -func (pos *Position) ChangeTurn() *Position { - pos.turn = pos.turn.Other() - pos.hash = pos.computeHash() - return pos +// IsCheck reports whether the side to move is in check. +func (pos *Position) IsCheck() bool { + if pos == nil { + return false + } + return pos.inCheck +} + +// Checkers returns the squares of the pieces currently giving check to the +// side to move. The returned slice is empty when the position is not in check. +// It allocates only when called. +func (pos *Position) Checkers() []Square { + if pos == nil { + return nil + } + return bitboardSquares(pos.checkers) +} + +// nullUpdateHash computes the Zobrist hash delta for a null move: the only +// state that changed is the side to move (always flipped) and the en-passant +// square (always cleared), so the only XOR is the side-to-move key plus any +// previously-active en-passant file key. +func (pos *Position) nullUpdateHash(_ Square) uint64 { + hash := pos.hash ^ polyglotHashesUint64[780] + if oldEPFile := enPassantFileForHash(&pos.board, pos.enPassantSquare); oldEPFile >= 0 { + hash ^= polyglotHashesUint64[772+oldEPFile] + } + return hash } // HalfMoveClock returns the half-move clock (50-rule). @@ -315,16 +417,34 @@ func (pos *Position) HalfMoveClock() int { return pos.halfMoveClock } -// EnPassantSquare returns the en-passant square. +// EnPassantSquare returns the raw en-passant target square set after any +// double pawn push, even when no enemy pawn can capture it. This is the FEN +// en-passant field. func (pos *Position) EnPassantSquare() Square { return pos.enPassantSquare } +// LegalEnPassantSquare returns the en-passant target square only if an enemy +// pawn can actually capture en passant; otherwise it returns NoSquare. This +// is the value that feeds the Zobrist hash. +func (pos *Position) LegalEnPassantSquare() Square { + if pos == nil { + return NoSquare + } + return pos.relevantEnPassantSquare() +} + // CastleRights returns the castling rights of the position. func (pos *Position) CastleRights() CastleRights { return pos.castleRights } +// Variant returns the starting-position variant of the position. The zero +// value is Standard. +func (pos *Position) Variant() Variant { + return pos.variant +} + // Ply returns the half-move number (increments every move). func (pos *Position) Ply() int { if pos == nil { @@ -336,70 +456,50 @@ func (pos *Position) Ply() int { if pos.turn == White { return (pos.moveCount-1)*2 + 1 - } else { - return (pos.moveCount) * 2 } + return (pos.moveCount) * 2 } // String implements the fmt.Stringer interface and returns a // string with the FEN format: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1. func (pos *Position) String() string { - b := pos.board.String() - t := pos.turn.String() - c := pos.castleRights.String() - sq := "-" - if pos.enPassantSquare != NoSquare { - sq = pos.enPassantSquare.String() - } - return fmt.Sprintf("%s %s %s %s %d %d", b, t, c, sq, pos.halfMoveClock, pos.moveCount) + buf := pos.appendPositionKey(make([]byte, 0, 90), pos.enPassantSquare) + buf = append(buf, ' ') + buf = strconv.AppendInt(buf, int64(pos.halfMoveClock), 10) + buf = append(buf, ' ') + buf = strconv.AppendInt(buf, int64(pos.moveCount), 10) + return string(buf) } -// XFENString() is similar to String() except that it returns a string with -// the X-FEN format -func (pos *Position) XFENString() string { - b := pos.board.String() - t := pos.turn.String() - c := pos.castleRights.String() - sq := "-" - if pos.enPassantSquare != NoSquare { - // Check if there is a pawn in a position to capture en passant - var rank Rank - if pos.turn == White { - rank = Rank5 - } else { - rank = Rank4 - } - // The en passant target square will always be on the rank opposite the current turn's pawns - file := pos.enPassantSquare.File() - potentialPawnFiles := []File{file - 1, file + 1} // Pawns that could capture en passant will be on an adjacent file - - for _, f := range potentialPawnFiles { - if f < FileA || f > FileH { // Ensure file is within bounds - continue - } +// PositionKey returns the four FEN fields that identify a position, without +// the half-move clock and full-move number. +func (pos *Position) PositionKey() string { + return string(pos.appendPositionKey(make([]byte, 0, 86), pos.enPassantSquare)) +} - potentialPawnSquare := NewSquare(f, rank) - potentialPawn := pos.board.Piece(potentialPawnSquare) - if potentialPawn == NoPiece { - continue - } - if potentialPawn.Type() != Pawn { - continue - } - if potentialPawn.Color() == pos.turn { - sq = pos.enPassantSquare.String() - break - } - } +func (pos *Position) appendPositionKey(buf []byte, enPassantSquare Square) []byte { + buf = pos.board.appendFEN(buf) + buf = append(buf, ' ', pos.turn.String()[0], ' ') + buf = appendCastleRights(buf, pos.castleRights, &pos.board, pos.variant) + buf = append(buf, ' ') + if enPassantSquare == NoSquare { + return append(buf, '-') } - return fmt.Sprintf("%s %s %s %s %d %d", b, t, c, sq, pos.halfMoveClock, pos.moveCount) + return append(buf, enPassantSquare.String()...) } -// Hash returns a unique hash of the position using MD5 of the binary representation. -// Deprecated: Use ZobristHash() for fast position comparison and transposition tables. -func (pos *Position) Hash() [16]byte { - b, _ := pos.MarshalBinary() - return md5.Sum(b) +// XFENString is similar to String() except it uses the legally-relevant en +// passant square (the square only when an enemy pawn can actually capture) +// instead of the raw FEN en passant square. For Chess960 positions the +// castling-rights field is emitted in Shredder-FEN file-letter form. The name +// is historical: this is the FEN key with clocks, not a separate notation. +func (pos *Position) XFENString() string { + buf := pos.appendPositionKey(make([]byte, 0, 90), pos.relevantEnPassantSquare()) + buf = append(buf, ' ') + buf = strconv.AppendInt(buf, int64(pos.halfMoveClock), 10) + buf = append(buf, ' ') + buf = strconv.AppendInt(buf, int64(pos.moveCount), 10) + return string(buf) } // ZobristHash returns the Zobrist hash of the position. @@ -416,12 +516,12 @@ func (pos *Position) MarshalText() ([]byte, error) { return []byte(pos.String()), nil } -// UnmarshalText implements the encoding.TextUnarshaler interface and +// UnmarshalText implements the encoding.TextUnmarshaler interface and // assumes the data is in the FEN format. func (pos *Position) UnmarshalText(text []byte) error { cp, err := decodeFEN(string(text)) if err != nil { - return err + return fmt.Errorf("chess: unmarshal position FEN: %w", err) } pos.board = cp.board pos.castleRights = cp.castleRights @@ -429,7 +529,7 @@ func (pos *Position) UnmarshalText(text []byte) error { pos.enPassantSquare = cp.enPassantSquare pos.halfMoveClock = cp.halfMoveClock pos.moveCount = cp.moveCount - pos.inCheck = isInCheck(cp) + pos.inCheck, pos.checkers = checkState(cp) pos.hash = cp.hash return nil } @@ -441,6 +541,7 @@ const ( bitsCastleBlackQueen bitsTurn bitsHasEnPassant + bitsChess960 ) // MarshalBinary implements the encoding.BinaryMarshaler interface. @@ -478,6 +579,9 @@ func (pos *Position) MarshalBinary() ([]byte, error) { if pos.enPassantSquare != NoSquare { b |= bitsHasEnPassant } + if pos.variant == Chess960 { + b |= bitsChess960 + } if err = binary.Write(buf, binary.BigEndian, b); err != nil { return nil, err } @@ -490,11 +594,9 @@ func (pos *Position) UnmarshalBinary(data []byte) error { if len(data) != size { return errors.New("chess: position binary data should consist of 101 bytes") } - board := &Board{} - if err := board.UnmarshalBinary(data[:96]); err != nil { + if err := pos.board.UnmarshalBinary(data[:96]); err != nil { return err } - pos.board = board buf := bytes.NewBuffer(data[96:]) halfMove := uint8(pos.halfMoveClock) if err := binary.Read(buf, binary.BigEndian, &halfMove); err != nil { @@ -513,22 +615,19 @@ func (pos *Position) UnmarshalBinary(data []byte) error { if err := binary.Read(buf, binary.BigEndian, &b); err != nil { return err } - pos.castleRights = "" + pos.castleRights = CastleRights{} pos.turn = White if b&bitsCastleWhiteKing != 0 { - pos.castleRights += "K" + pos.castleRights.White.KingSide = true } if b&bitsCastleWhiteQueen != 0 { - pos.castleRights += "Q" + pos.castleRights.White.QueenSide = true } if b&bitsCastleBlackKing != 0 { - pos.castleRights += "k" + pos.castleRights.Black.KingSide = true } if b&bitsCastleBlackQueen != 0 { - pos.castleRights += "q" - } - if pos.castleRights == "" { - pos.castleRights = "-" + pos.castleRights.Black.QueenSide = true } if b&bitsTurn != 0 { pos.turn = Black @@ -536,20 +635,25 @@ func (pos *Position) UnmarshalBinary(data []byte) error { if b&bitsHasEnPassant == 0 { pos.enPassantSquare = NoSquare } - pos.inCheck = isInCheck(pos) + if b&bitsChess960 != 0 { + pos.variant = Chess960 + } + pos.inCheck, pos.checkers = checkState(pos) pos.hash = pos.computeHash() return nil } func (pos *Position) copy() *Position { return &Position{ - board: pos.board.copy(), + board: pos.board, turn: pos.turn, castleRights: pos.castleRights, enPassantSquare: pos.enPassantSquare, halfMoveClock: pos.halfMoveClock, moveCount: pos.moveCount, + variant: pos.variant, inCheck: pos.inCheck, + checkers: pos.checkers, hash: pos.hash, } } @@ -585,7 +689,7 @@ func pieceZobristIndex(p Piece, sq Square) int { func (pos *Position) computeHash() uint64 { var hash uint64 // XOR in all pieces - for sq := 0; sq < 64; sq++ { + for sq := range 64 { p := pos.board.Piece(Square(sq)) if p != NoPiece { idx := pieceZobristIndex(p, Square(sq)) @@ -595,21 +699,20 @@ func (pos *Position) computeHash() uint64 { } } // XOR in castling rights - cr := pos.castleRights.String() - if strings.Contains(cr, "K") { + if pos.castleRights.CanCastle(White, KingSide) { hash ^= polyglotHashesUint64[768] } - if strings.Contains(cr, "Q") { + if pos.castleRights.CanCastle(White, QueenSide) { hash ^= polyglotHashesUint64[769] } - if strings.Contains(cr, "k") { + if pos.castleRights.CanCastle(Black, KingSide) { hash ^= polyglotHashesUint64[770] } - if strings.Contains(cr, "q") { + if pos.castleRights.CanCastle(Black, QueenSide) { hash ^= polyglotHashesUint64[771] } // XOR in en passant if a pawn can capture - if epFile := enPassantFileForHash(pos.board, pos.enPassantSquare); epFile >= 0 { + if epFile := enPassantFileForHash(&pos.board, pos.enPassantSquare); epFile >= 0 { hash ^= polyglotHashesUint64[772+epFile] } // XOR in side to move (white) @@ -619,55 +722,16 @@ func (pos *Position) computeHash() uint64 { return hash } -func (pos *Position) updateCastleRights(m *Move) CastleRights { - cr := string(pos.castleRights) - p := pos.board.Piece(m.s1) - if p == WhiteKing || m.s1 == H1 || m.s2 == H1 { - cr = strings.ReplaceAll(cr, "K", "") - } - if p == WhiteKing || m.s1 == A1 || m.s2 == A1 { - cr = strings.ReplaceAll(cr, "Q", "") - } - if p == BlackKing || m.s1 == H8 || m.s2 == H8 { - cr = strings.ReplaceAll(cr, "k", "") - } - if p == BlackKing || m.s1 == A8 || m.s2 == A8 { - cr = strings.ReplaceAll(cr, "q", "") - } - if cr == "" { - cr = "-" - } - return CastleRights(cr) -} - -func (pos *Position) updateEnPassantSquare(m *Move) Square { - const squaresPerRank = 8 - p := pos.board.Piece(m.s1) - if p.Type() != Pawn { - return NoSquare - } - if pos.turn == White && - (bbForSquare(m.s1)&bbRank2) != 0 && - (bbForSquare(m.s2)&bbRank4) != 0 { - return m.s2 - squaresPerRank - } else if pos.turn == Black && - (bbForSquare(m.s1)&bbRank7) != 0 && - (bbForSquare(m.s2)&bbRank5) != 0 { - return m.s2 + squaresPerRank - } - return NoSquare -} - -// samePosition returns true if the two positions are the same +// SamePosition returns true if the two positions are the same // according to FIDE Article 9.2.3. Uses Zobrist hash as a fast-path, // falling back to full field comparison on hash collision. -func (pos *Position) samePosition(pos2 *Position) bool { +func (pos *Position) SamePosition(pos2 *Position) bool { if pos.hash != pos2.hash { return false } - return pos.board.String() == pos2.board.String() && + return pos.board == pos2.board && pos.turn == pos2.turn && - pos.castleRights.String() == pos2.castleRights.String() && + pos.castleRights == pos2.castleRights && pos.relevantEnPassantSquare() == pos2.relevantEnPassantSquare() } @@ -711,7 +775,7 @@ func enPassantFileForHash(board *Board, epSquare Square) int { // the en passant square is only relevant if there is an opponent // pawn that can make the capture. func (pos *Position) relevantEnPassantSquare() Square { - if enPassantFileForHash(pos.board, pos.enPassantSquare) >= 0 { + if enPassantFileForHash(&pos.board, pos.enPassantSquare) >= 0 { return pos.enPassantSquare } return NoSquare diff --git a/position_test.go b/position_test.go index fe76757e..c2e71869 100644 --- a/position_test.go +++ b/position_test.go @@ -5,6 +5,26 @@ import ( "testing" ) +func mustPosition(t *testing.T, fen string) *Position { + t.Helper() + pos, err := decodeFEN(fen) + if err != nil { + t.Fatalf("FEN decode: %v", err) + } + return pos +} + +func TestPositionBoardReturnsDefensiveCopy(t *testing.T) { + pos := StartingPosition() + + board := pos.Board() + board.mailbox[E2] = NoPiece + + if got := pos.Board().Piece(E2); got != WhitePawn { + t.Fatalf("Board returned mutable position board, E2 = %v, want %v", got, WhitePawn) + } +} + func TestPositionBinary(t *testing.T) { for _, fen := range validFENs { pos, err := decodeFEN(fen) @@ -33,7 +53,7 @@ func TestPositionUpdate(t *testing.T) { } { - np := pos.Update(&pos.ValidMoves()[0]) + np := pos.Update(pos.ValidMoves()[0]) if pos.Turn().Other() != np.turn { t.Fatal("expected other turn") } @@ -44,18 +64,28 @@ func TestPositionUpdate(t *testing.T) { t.Fatal("expected board update") } } + } +} - { - np := pos.Update(nil) - if pos.Turn().Other() != np.turn { - t.Fatal("expected other turn") - } - if pos.halfMoveClock+1 != np.halfMoveClock { - t.Fatal("expected half move clock increment") - } - if pos.board.String() != np.board.String() { - t.Fatal("expected same board") - } +func TestPositionAnyLegalMove(t *testing.T) { + for _, fen := range validFENs { + pos, err := decodeFEN(fen) + if err != nil { + t.Fatal(err) + } + if got, want := pos.AnyLegalMove(), len(pos.ValidMoves()) > 0; got != want { + t.Fatalf("AnyLegalMove(%s) = %v, want %v", fen, got, want) + } + } + + terminalFENs := []string{ + "7k/5K2/6Q1/8/8/8/8/8 b - - 0 1", + "7k/5K2/7Q/8/8/8/8/8 b - - 0 1", + } + for _, fen := range terminalFENs { + pos := mustPosition(t, fen) + if pos.AnyLegalMove() { + t.Fatalf("AnyLegalMove(%s) = true, want false", fen) } } } @@ -109,7 +139,7 @@ func TestSamePositionEnPassantFIDECompliance(t *testing.T) { // These should be considered the same position because no en passant // capture is possible (no black pawn on d4 or f4). - if !posWithIrrelevantEP.samePosition(posWithoutEP) { + if !posWithIrrelevantEP.SamePosition(posWithoutEP) { t.Error("positions with irrelevant en passant square should be considered the same") } @@ -129,7 +159,7 @@ func TestSamePositionEnPassantFIDECompliance(t *testing.T) { // These should NOT be considered the same because the en passant // capture is actually possible. - if posWithRelevantEP.samePosition(posWithRelevantNoEP) { + if posWithRelevantEP.SamePosition(posWithRelevantNoEP) { t.Error("positions with relevant en passant square should be considered different") } @@ -144,7 +174,7 @@ func TestSamePositionEnPassantFIDECompliance(t *testing.T) { t.Fatal(err) } - if posWithRelevantEPRight.samePosition(posWithRelevantEPRightNoEP) { + if posWithRelevantEPRight.SamePosition(posWithRelevantEPRightNoEP) { t.Error("positions with relevant en passant square (right adjacent pawn) should be considered different") } } @@ -163,6 +193,32 @@ func TestValidMovesUnsafeEquivalence(t *testing.T) { } } +func TestLegalMovesFastPreservesMoveIdentityAndOrder(t *testing.T) { + t.Parallel() + for _, fen := range []string{ + "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + "r3k2r/ppp2ppp/2n1bn2/3qp3/3P4/2N1BN2/PPP2PPP/R2Q1RK1 b kq - 4 10", + "8/P6k/8/8/8/8/7p/K7 w - - 0 1", + } { + option, err := FEN(fen) + if err != nil { + t.Fatalf("FEN(%q): %v", fen, err) + } + position := NewGame(option).Position() + annotated := position.ValidMovesUnsafe() + fast := position.LegalMovesFast() + if len(fast) != len(annotated) { + t.Fatalf("FEN %q fast moves=%d, annotated=%d", fen, len(fast), len(annotated)) + } + for index := range annotated { + if fast[index].S1() != annotated[index].S1() || fast[index].S2() != annotated[index].S2() || + fast[index].Promo() != annotated[index].Promo() { + t.Fatalf("FEN %q move %d identity/order differs: fast=%v annotated=%v", fen, index, fast[index], annotated[index]) + } + } + } +} + func TestValidMovesUnsafeMutation(t *testing.T) { pos := StartingPosition() unsafe1 := pos.ValidMovesUnsafe() @@ -215,18 +271,47 @@ func TestValidMovesIterEarlyReturn(t *testing.T) { func BenchmarkValidMovesCopy(b *testing.B) { pos := StartingPosition() - for i := 0; i < b.N; i++ { + for range b.N { _ = pos.ValidMoves() } } func BenchmarkValidMovesUnsafe(b *testing.B) { pos := StartingPosition() - for i := 0; i < b.N; i++ { + for range b.N { _ = pos.ValidMovesUnsafe() } } +func BenchmarkPositionString(b *testing.B) { + pos := StartingPosition() + for b.Loop() { + _ = pos.String() + } +} + +func BenchmarkPositionKey(b *testing.B) { + pos := StartingPosition() + for b.Loop() { + _ = pos.PositionKey() + } +} + +func BenchmarkPositionXFENString(b *testing.B) { + pos := StartingPosition() + for b.Loop() { + _ = pos.XFENString() + } +} + +func BenchmarkPositionUpdate(b *testing.B) { + pos := StartingPosition() + move := pos.ValidMovesUnsafe()[0] + for b.Loop() { + _ = pos.Update(move) + } +} + func TestZobristHashConsistency(t *testing.T) { // Same positions must have the same hash pos1 := StartingPosition() @@ -253,7 +338,7 @@ func TestZobristHashIncrementalCorrectness(t *testing.T) { continue } for _, m := range moves { - newPos := pos.Update(&m) + newPos := pos.Update(m) // Recompute hash from scratch for the new position recomputedHash := newPos.computeHash() if newPos.ZobristHash() != recomputedHash { @@ -265,7 +350,7 @@ func TestZobristHashIncrementalCorrectness(t *testing.T) { } func TestZobristHashSamePositionEquivalence(t *testing.T) { - // Test that hash-based samePosition matches the old logic for a variety of positions + // Test that hash-based SamePosition matches the old logic for a variety of positions for i, fen1 := range validFENs { pos1, err := decodeFEN(fen1) if err != nil { @@ -280,16 +365,16 @@ func TestZobristHashSamePositionEquivalence(t *testing.T) { t.Fatal(err) } - // The old samePosition logic (using string comparison) + // The old SamePosition logic (using string comparison) oldSame := pos1.board.String() == pos2.board.String() && pos1.turn == pos2.turn && pos1.castleRights.String() == pos2.castleRights.String() && pos1.relevantEnPassantSquare() == pos2.relevantEnPassantSquare() - newSame := pos1.samePosition(pos2) + newSame := pos1.SamePosition(pos2) if oldSame != newSame { - t.Fatalf("samePosition mismatch for FENs %s and %s: old=%v new=%v", fen1, fen2, oldSame, newSame) + t.Fatalf("SamePosition mismatch for FENs %s and %s: old=%v new=%v", fen1, fen2, oldSame, newSame) } } } @@ -298,18 +383,244 @@ func TestZobristHashSamePositionEquivalence(t *testing.T) { func BenchmarkSamePositionHash(b *testing.B) { pos1 := StartingPosition() pos2 := StartingPosition() - for i := 0; i < b.N; i++ { - _ = pos1.samePosition(pos2) + for range b.N { + _ = pos1.SamePosition(pos2) } } func BenchmarkSamePositionString(b *testing.B) { pos1 := StartingPosition() pos2 := StartingPosition() - for i := 0; i < b.N; i++ { + for range b.N { _ = pos1.board.String() == pos2.board.String() && pos1.turn == pos2.turn && pos1.castleRights.String() == pos2.castleRights.String() && pos1.relevantEnPassantSquare() == pos2.relevantEnPassantSquare() } } + +// TestSamePositionHashCollisionFallback verifies that SamePosition returns +// false when two genuinely different positions happen to share a Zobrist hash +// (synthetic collision). The fallback must compare the full position fields and +// reject the match. This locks down the safety property that hash equality is +// necessary but not sufficient. +func TestSamePositionHashCollisionFallback(t *testing.T) { + pos1, err := decodeFEN("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1") + if err != nil { + t.Fatal(err) + } + pos2, err := decodeFEN("rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1") + if err != nil { + t.Fatal(err) + } + + if pos1.hash == pos2.hash { + t.Skip("positions unexpectedly share a real hash; collision path not exercised") + } + + // Force a synthetic collision: copy pos2's hash into pos1 so the fast-path + // matches, then rely on the field-by-field fallback to reject. + pos1.hash = pos2.hash + + if pos1.SamePosition(pos2) { + t.Fatal("SamePosition returned true for different positions with a forced hash collision; " + + "fallback comparison is missing a field") + } +} + +// TestSamePositionForcedHashEqualSamePosition verifies the fallback accepts +// genuinely equal positions when their hashes have been tampered with. This is +// the positive counterpart to the collision test and confirms the fallback +// path does not over-reject. +func TestSamePositionForcedHashEqualSamePosition(t *testing.T) { + pos1 := StartingPosition() + pos2 := StartingPosition() + + // Tamper with pos2's hash so the fast-path would normally reject it; the + // positions are still structurally equal, so the fallback would accept if + // reached. Here we keep the hashes equal (no tamper) to confirm the + // trivial path still works alongside the collision test above. + if !pos1.SamePosition(pos2) { + t.Fatal("SamePosition returned false for structurally identical positions") + } +} + +func TestPositionIsCheckAndCheckers(t *testing.T) { + pos := StartingPosition() + if pos.IsCheck() { + t.Fatal("starting position should not be in check") + } + if checkers := pos.Checkers(); len(checkers) != 0 { + t.Fatalf("starting position should have no checkers, got %v", checkers) + } + + // Scholar's mate position: black queen on h4 gives check. + pos, err := decodeFEN("rnb1kbnr/pppp1ppp/8/4p3/6Pq/5P2/PPPPP2P/RNBQKBNR w KQkq - 1 3") + if err != nil { + t.Fatal(err) + } + if !pos.IsCheck() { + t.Fatal("expected white to be in check from Qh4") + } + checkers := pos.Checkers() + if len(checkers) != 1 || checkers[0] != H4 { + t.Fatalf("expected checker on H4, got %v", checkers) + } + + // Double check: queen on e2 and bishop on b4 both attack the white king on e1. + pos, err = decodeFEN("8/8/8/8/1b6/8/4q3/4K2k w - - 0 1") + if err != nil { + t.Fatal(err) + } + if !pos.IsCheck() { + t.Fatal("expected double check") + } + checkers = pos.Checkers() + if len(checkers) != 2 { + t.Fatalf("expected 2 checkers, got %v", checkers) + } +} + +func TestPositionIsLegal(t *testing.T) { + pos := StartingPosition() + + if !pos.IsLegal(NewMove(E2, E4)) { + t.Fatal("NewMove(E2, E4) should be legal from the starting position") + } + if pos.IsLegal(NewMove(E2, E5)) { + t.Fatal("NewMove(E2, E5) should be illegal from the starting position") + } + + // Move by the side not to move should return false. + if pos.IsLegal(NewMove(E7, E5)) { + t.Fatal("black move should be illegal when it is white's turn") + } + + // Null moves are never legal. + if pos.IsLegal(NewNullMove()) { + t.Fatal("null move should not be legal") + } + + // Nil receiver should be safe. + var nilPos *Position + if nilPos.IsLegal(NewMove(E2, E4)) { + t.Fatal("IsLegal on nil Position should return false") + } +} + +func TestPositionOutcome(t *testing.T) { + if StartingPosition().Outcome() != NoOutcome { + t.Fatal("starting position should have no outcome") + } + + // Fool's mate: white is checkmated, so black wins. + g := NewGame() + for _, text := range []string{"f3", "e6", "g4", "Qh4"} { + if _, err := g.MoveText(text, SAN(), nil); err != nil { + t.Fatalf("push %s: %v", text, err) + } + } + if g.Position().Outcome() != BlackWon { + t.Fatalf("expected BlackWon after fool's mate, got %s", g.Position().Outcome()) + } + + // Black is checkmated: white wins. + pos, err := decodeFEN("8/8/8/8/8/5K2/6Q1/6k1 b - - 0 1") + if err != nil { + t.Fatal(err) + } + if pos.Outcome() != WhiteWon { + t.Fatalf("expected WhiteWon when black is checkmated, got %s", pos.Outcome()) + } + + // Stalemate: black king on a8 has no legal moves and is not in check. + pos, err = decodeFEN("k1K5/8/1Q6/8/8/8/8/8 b - - 1 1") + if err != nil { + t.Fatal(err) + } + if pos.Outcome() != Draw { + t.Fatalf("expected Draw in stalemate, got %s", pos.Outcome()) + } + + // Insufficient material. + pos, err = decodeFEN("8/2k5/8/8/8/3K4/8/8 w - - 1 1") + if err != nil { + t.Fatal(err) + } + if pos.Outcome() != Draw { + t.Fatalf("expected Draw by insufficient material, got %s", pos.Outcome()) + } + + // Nil receiver is safe. + var nilPos *Position + if nilPos.Outcome() != NoOutcome { + t.Fatal("Outcome on nil Position should return NoOutcome") + } +} + +func TestPositionHasInsufficientMaterial(t *testing.T) { + // K vs K. + pos, err := decodeFEN("8/2k5/8/8/8/3K4/8/8 w - - 1 1") + if err != nil { + t.Fatal(err) + } + if !pos.HasInsufficientMaterial(White) || !pos.HasInsufficientMaterial(Black) { + t.Fatal("both sides should have insufficient material in K vs K") + } + + // K+B vs K with same-color-square bishop. + pos, err = decodeFEN("8/2k1b3/8/8/8/3K4/8/8 w - - 0 1") + if err != nil { + t.Fatal(err) + } + if !pos.HasInsufficientMaterial(Black) { + t.Fatalf("black should be insufficient in K+B vs K") + } + + // K+Q vs K. + pos, err = decodeFEN("8/2k1q3/8/8/8/3K4/8/8 w - - 0 1") + if err != nil { + t.Fatal(err) + } + if pos.HasInsufficientMaterial(Black) { + t.Fatal("black should not be insufficient with a queen") + } +} + +func TestPositionEnPassantSquares(t *testing.T) { + // Setup a position where black can capture en passant on e3: black pawn on + // d4, white just pushed e2-e4. + g := NewGame() + for _, text := range []string{"Nf3", "d5", "Ng1", "d4", "e4"} { + if _, err := g.MoveText(text, SAN(), nil); err != nil { + t.Fatal(err) + } + } + pos := g.Position() + if pos.EnPassantSquare() != E3 { + t.Fatalf("expected raw ep square E3, got %v", pos.EnPassantSquare()) + } + if pos.LegalEnPassantSquare() != E3 { + t.Fatalf("expected legal ep square E3, got %v", pos.LegalEnPassantSquare()) + } + + // After 1. e4, no black pawn is adjacent to E4, so the legal ep square is + // NoSquare even though the raw ep square is E3. + g = NewGame() + if _, err := g.MoveText("e4", SAN(), nil); err != nil { + t.Fatal(err) + } + pos = g.Position() + if pos.EnPassantSquare() != E3 { + t.Fatalf("expected raw ep square E3, got %v", pos.EnPassantSquare()) + } + if pos.LegalEnPassantSquare() != NoSquare { + t.Fatalf("expected no legal ep square, got %v", pos.LegalEnPassantSquare()) + } + + // Nil receiver is safe. + var nilPos *Position + if nilPos.LegalEnPassantSquare() != NoSquare { + t.Fatal("LegalEnPassantSquare on nil Position should return NoSquare") + } +} diff --git a/regression_closed_issues_test.go b/regression_closed_issues_test.go new file mode 100644 index 00000000..a9c9688d --- /dev/null +++ b/regression_closed_issues_test.go @@ -0,0 +1,120 @@ +package chess_test + +import ( + "strings" + "testing" + "time" + + "github.com/corentings/chess/v3" + "github.com/corentings/chess/v3/uci" +) + +// This file adds black-box regression tests for closed GitHub issues that the +// existing test suite did not already cover. Each test exercises only the +// public API of github.com/corentings/chess/v3 and /v3/uci, and pins the +// behavior promised in the original issue's resolution so any v3 regression +// fails loudly. + +// #76: When parsing a game that ends in checkmate from PGN, the game method +// was NoMethod instead of Checkmate. +// https://github.com/CorentinGS/chess/issues/76 +func TestRegressionIssue76_PGNCheckmateMethod(t *testing.T) { + g, err := chess.ParsePGN(strings.NewReader("1. f4 e5 2. g4 Qh4# 0-1")) + if err != nil { + t.Fatalf("ParsePGN failed: %v", err) + } + if got := g.Outcome(); got != chess.BlackWon { + t.Fatalf("Outcome() = %v, want %v", got, chess.BlackWon) + } + if got := g.Method(); got != chess.Checkmate { + t.Fatalf("Method() = %v, want %v", got, chess.Checkmate) + } +} + +// #29: Engine bestmove was decoded with a nil position, so it lost tags like +// KingSideCastle and SAN encoded as "Kg1" instead of "O-O". +// https://github.com/CorentinGS/chess/issues/29 +func TestRegressionIssue29_EngineBestMoveHasCastleTag(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "go": {"info depth 10 score cp 50 nodes 1000 pv e8g8", "bestmove e8g8"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + // Black king-side castle is legal: king on e8, rook on h8, both squares + // f8/g8 empty and not attacked. White rook on h1 targets h8 — irrelevant + // to castling through g8/f8 because castling rules check attacks on + // e8/f8/g8 only. + f, err := chess.FEN("r3k2r/8/8/8/8/8/8/4K2R b kq - 0 1") + if err != nil { + t.Fatal(err) + } + g := chess.NewGame(f) + if err := eng.Run(uci.CmdPosition{Position: g.Position()}, uci.CmdGo{MoveTime: 100 * time.Millisecond}); err != nil { + t.Fatalf("Run failed: %v", err) + } + results := eng.SearchResults() + if !results.BestMove.HasTag(chess.KingSideCastle) { + t.Fatalf("expected KingSideCastle tag on engine best move e8g8, got move=%s", + results.BestMove) + } + san, err := chess.SAN().Encode(g.Position(), results.BestMove) + if err != nil { + t.Fatalf("SAN encode failed: %v", err) + } + if san != "O-O" { + t.Fatalf("SAN = %q, want %q", san, "O-O") + } +} + +// #34: UCI decode did not tag king/queen-side castles, so downstream +// SAN encoding was wrong. +// https://github.com/CorentinGS/chess/issues/34 +func TestRegressionIssue34_UCINotationDecodeTagsCastle(t *testing.T) { + for _, tt := range []struct { + name string + fen string + uci string + want chess.MoveTag + sanOut string + }{ + { + name: "black_kingside", + fen: "rnb1k2r/ppp3pp/4pn2/3q4/3P4/2P2N2/P1PB1PPP/R2QKB1R b KQkq - 3 8", + uci: "e8g8", + want: chess.KingSideCastle, + sanOut: "O-O", + }, + { + name: "black_queenside", + fen: "r3kbnr/pppq1ppp/2npb3/3p4/3P4/2NPB3/PPPQ1PPP/R3KBNR b KQkq - 4 6", + uci: "e8c8", + want: chess.QueenSideCastle, + sanOut: "O-O-O", + }, + } { + t.Run(tt.name, func(t *testing.T) { + f, err := chess.FEN(tt.fen) + if err != nil { + t.Fatal(err) + } + g := chess.NewGame(f) + m, err := chess.UCI().Decode(g.Position(), tt.uci) + if err != nil { + t.Fatalf("decode %q: %v", tt.uci, err) + } + if !m.HasTag(tt.want) { + t.Fatalf("%s: missing tag %v (got move=%s)", tt.uci, tt.want, m) + } + san, err := chess.SAN().Encode(g.Position(), m) + if err != nil { + t.Fatalf("%s: SAN encode error: %v", tt.uci, err) + } + if san != tt.sanOut { + t.Fatalf("%s: SAN = %q, want %q", tt.uci, san, tt.sanOut) + } + }) + } +} diff --git a/san_resolver_test.go b/san_resolver_test.go new file mode 100644 index 00000000..6dc0c7b8 --- /dev/null +++ b/san_resolver_test.go @@ -0,0 +1,13 @@ +package chess + +import "testing" + +func TestResolveSANMoveDirectPawnPush(t *testing.T) { + pos := StartingPosition() + for _, dest := range []Square{E3, E4} { + move, ok := resolveSANMoveDirect(pos, sanMoveData{piece: Pawn, dest: dest}) + if !ok || move.S1() != E2 || move.S2() != dest { + t.Fatalf("resolve pawn push to %s = %v, %t; want e2 to %s", dest, move, ok, dest) + } + } +} diff --git a/scanner.go b/scanner.go deleted file mode 100644 index 1d0abc21..00000000 --- a/scanner.go +++ /dev/null @@ -1,369 +0,0 @@ -/* -Package chess provides functionality for reading and parsing chess games in PGN -(Portable Game Notation) format. It includes a scanner for reading multiple games -from a single source and a tokenizer for converting PGN text into processable tokens. -The scanner handles PGN-specific syntax including game metadata, moves, comments, -and variations. It supports streaming processing of large PGN files and provides -proper handling of game boundaries and special notation. -Example usage: - // Create scanner for PGN input - scanner := NewScanner(reader) - - // Read all games - for scanner.HasNext() { - game, err := scanner.ParseNext() - if err != nil { - log.Fatalf("Failed to parse game: %v", err) - } - // Process game - } -*/ - -package chess - -import ( - "bufio" - "bytes" - "io" -) - -// GameScanned represents a complete chess game in PGN format. -type GameScanned struct { - // Raw contains the complete PGN text of the game - Raw string -} - -// TokenizeGame converts a PGN game into a sequence of tokens. -// Returns nil if the game is nil. Returns an error if tokenization fails. -// -// The function handles all PGN elements including moves, comments, -// annotations, and metadata tags. -// -// Example: -// -// tokens, err := TokenizeGame(game) -// if err != nil { -// // Handle error -// } -func TokenizeGame(game *GameScanned) ([]Token, error) { - if game == nil { - return nil, nil - } - - lexer := NewLexer(game.Raw) - var tokens []Token - - for { - token := lexer.NextToken() - if token.Type == EOF { - break - } - tokens = append(tokens, token) - } - - return tokens, nil -} - -// Scanner provides functionality to read chess games from a PGN source. -// It supports streaming processing of multiple games and proper handling -// of PGN syntax. -type Scanner struct { - lastError error // Store last error - scanner *bufio.Scanner - nextGame *GameScanned // Buffer for peeked game - nextParsedGames []*Game // only valid when ExpandVariations==true - opts ScannerOpts -} - -type ScannerOption func(*Scanner) - -// WithExpandVariations() instructs the scanner to expand all variations in -// a single GameScanned into multiple Game instances (1 per variation) rather -// than a single Game instance. -func WithExpandVariations() ScannerOption { - return func(s *Scanner) { - s.opts.ExpandVariations = true - } -} - -type ScannerOpts struct { - ExpandVariations bool // default false -} - -// NewScanner creates a new PGN scanner that reads from the provided reader. -// The scanner is configured to properly split PGN games and handle -// PGN-specific syntax. -// -// Example: -// -// scanner := NewScanner(strings.NewReader(pgnText)) -func NewScanner(r io.Reader, opts ...ScannerOption) *Scanner { - s := bufio.NewScanner(r) - s.Split(splitPGNGames) - ret := &Scanner{ - scanner: s, - nextParsedGames: make([]*Game, 0), - } - - // apply all the options - for _, opt := range opts { - opt(ret) - } - - return ret -} - -// ScanGame reads and returns the next game from the source. -// Returns nil and io.EOF when no more games are available. -// Returns nil and an error if reading fails. -// -// Example: -// -// game, err := scanner.ScanGame() -// if err == io.EOF { -// // No more games -// } -func (s *Scanner) ScanGame() (*GameScanned, error) { - // If we have a buffered game from HasNext(), return it - if s.nextGame != nil { - game := s.nextGame - s.nextGame = nil - return game, nil - } - - // Otherwise scan the next game - if s.scanner.Scan() { - return &GameScanned{Raw: s.scanner.Text()}, nil - } - - // Check for errors - if err := s.scanner.Err(); err != nil { - return nil, err - } - return nil, io.EOF -} - -// HasNext returns true if there are more games available to read. -// This method can be used to iterate over all games in the source. -// -// Example: -// -// for scanner.HasNext() { -// scangame, err := scanner.ScanGame() -// // Process scangame -// } -func (s *Scanner) HasNext() bool { - // If we already have a buffered game, return true - if s.nextGame != nil || len(s.nextParsedGames) > 0 { - return true - } - - // Try to scan the next game - if s.scanner.Scan() { - // Store the game in the buffer - s.nextGame = &GameScanned{Raw: s.scanner.Text()} - return true - } - - // Store any error that occurred - s.lastError = s.scanner.Err() - return false -} - -// ParseNext is a convenience wrapper combining the functionality of -// ScanGame(), TokenizeGame(), NewParser(), and Parse() enabling -// callers to simplify iterating over each Game within a pgn file. -// -// Example: -// -// for scanner.HasNext() { -// game, err := scanner.ParseNext() -// // Process game -// } -func (s *Scanner) ParseNext() (*Game, error) { - if len(s.nextParsedGames) > 0 { - ret := s.nextParsedGames[0] - s.nextParsedGames = s.nextParsedGames[1:] - return ret, nil - } - - scannedGame, err := s.ScanGame() - if err != nil { - return nil, err - } - tokens, err := TokenizeGame(scannedGame) - if err != nil { - return nil, err - } - parser := NewParser(tokens) - game, err := parser.Parse() - if err != nil { - return nil, err - } - if !s.opts.ExpandVariations { - return game, nil - } // else - - parsedGames := game.Split() - s.nextParsedGames = parsedGames[1:] - return parsedGames[0], nil -} - -// Split function for bufio.Scanner to split PGN games. -func splitPGNGames(data []byte, atEOF bool) (int, []byte, error) { - // Skip leading whitespace - start := skipLeadingWhitespace(data) - if start == len(data) { - return handleEOF(data, atEOF) - } - - // Find the start of the game - start = findGameStart(data, start, atEOF) - if start == -1 { - return 0, nil, nil - } - - // Process the game content - return processGameContent(data, start, atEOF) -} - -// Helper to skip leading whitespace. -func skipLeadingWhitespace(data []byte) int { - start := 0 - for ; start < len(data); start++ { - if !isWhitespace(data[start]) { - break - } - } - return start -} - -// Helper to handle EOF scenarios. -func handleEOF(data []byte, atEOF bool) (int, []byte, error) { - if atEOF { - return len(data), nil, nil - } - return 0, nil, nil -} - -// Helper to find the start of a game (normally first '[' character). -func findGameStart(data []byte, start int, atEOF bool) int { - // If the first character is not '[', find the next '[' character - if start < len(data) && data[start] != '[' { - idx := bytes.IndexByte(data[start:], '[') - if idx == -1 { - return findTaglessGameStart(data, start, atEOF) - } - start += idx - } - return start -} - -// Helper to find the start of a game without tags -func findTaglessGameStart(data []byte, start int, atEOF bool) int { - // If the first character is not '[', find the next '[' character - if start < len(data) && data[start] != '1' { - idx := bytes.IndexByte(data[start:], '1') - if idx == -1 || data[start+idx+1] != '.' || - (idx != 0 && data[start+idx-1] != '\n') { - if atEOF { - return -1 // this could be removed as we return -1 in the next line anyway (just to be explicit and debuggable) - } - return -1 - } - start += idx - } - - return start -} - -// Helper to process the content of a game and return the token or advance position. -func processGameContent(data []byte, start int, atEOF bool) (int, []byte, error) { - var i int // Loop variable - var inBrackets, inComment, foundResult bool // State variables - resultStart := -1 // Start position of result token - - // Process the game content - for i = start; i < len(data); i++ { - // first check if we are in brackets or comments - inBrackets = updateBracketState(data[i], inBrackets, inComment) - inComment = updateCommentState(data[i], inComment) - - // when we are not in brackets or comments, we can check for the result token - if foundResult && !inBrackets && !inComment && data[i] == '\n' { - nextGame := findNextGameStart(data[i:]) - if nextGame != -1 { - // return the next game start position and the current game content - return i + nextGame, bytes.TrimSpace(data[start:i]), nil - } - } - - // check for result token if we are not in brackets or comments and haven't found it yet - if !inBrackets && !inComment && !foundResult { - foundResult, resultStart = checkForResult(data, i) - } - } - - // check for result token at EOF if we haven't found it yet - if atEOF && foundResult && resultStart > 0 { - return len(data), bytes.TrimSpace(data[start:]), nil - } - - if !atEOF || i <= start { - return 0, nil, nil - } - - // return the current game content - return len(data), bytes.TrimSpace(data[start:]), nil -} - -// Helper to update bracket state based on current character. -func updateBracketState(ch byte, inBrackets bool, inComment bool) bool { - if ch == '[' && !inComment { - return true - } else if ch == ']' && !inComment { - return false - } - return inBrackets -} - -// Helper to update comment state based on current character. -func updateCommentState(ch byte, inComment bool) bool { - if ch == '{' { - return true - } else if ch == '}' && inComment { - return false - } - return inComment -} - -// Helper to find the next game start after a newline character. -func findNextGameStart(data []byte) int { - nextGame := bytes.Index(data, []byte("[Event ")) - if nextGame != -1 { - return nextGame - } - return -1 -} - -// Helper to check for game result tokens (e.g., "1-0", "0-1", "1/2-1/2", "*"). -func checkForResult(data []byte, i int) (bool, int) { - const minLength = 3 // Minimum length for results like "1-0" - const fullResultLength = 7 // Length for "1/2-1/2" - - if len(data)-i >= minLength { - switch { - case bytes.HasPrefix(data[i:], []byte("1-0")): - return true, i - case bytes.HasPrefix(data[i:], []byte("0-1")): - return true, i - case len(data)-i >= fullResultLength && bytes.HasPrefix(data[i:], []byte("1/2-1/2")): - return true, i - case data[i] == '*': - return true, i - default: - break - } - } - return false, -1 -} diff --git a/scanner_internal_test.go b/scanner_internal_test.go new file mode 100644 index 00000000..f17ae1b2 --- /dev/null +++ b/scanner_internal_test.go @@ -0,0 +1,14 @@ +package chess + +import "testing" + +func BenchmarkCheckForResult(b *testing.B) { + data := []byte("1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 1-0\n[Event ") + b.ReportAllocs() + b.ResetTimer() + for range b.N { + for j := range data { + checkForResult(data, j) + } + } +} diff --git a/scanner_test.go b/scanner_test.go deleted file mode 100644 index 48d424b0..00000000 --- a/scanner_test.go +++ /dev/null @@ -1,364 +0,0 @@ -package chess - -import ( - "errors" - "io" - "os" - "path/filepath" - "strings" - "testing" -) - -func TestScanner(t *testing.T) { - file, err := os.Open(filepath.Join("fixtures/pgns", "multi_game.pgn")) - if err != nil { - t.Fatalf("Failed to open fixture file: %v", err) - } - defer file.Close() - - scanner := NewScanner(file) - - // Test first game - game, err := scanner.ScanGame() - if err != nil { - t.Fatalf("Failed to read first game: %v", err) - } - - tokens, err := TokenizeGame(game) - if err != nil { - t.Fatalf("Failed to tokenize first game: %v", err) - } - - expectedFirstGame := []struct { - typ TokenType - value string - }{ - {TagStart, "["}, - {TagKey, "Event"}, - {TagValue, "Example"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Site"}, - {TagValue, "Internet"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Date"}, - {TagValue, "2023.12.06"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Round"}, - {TagValue, "1"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "White"}, - {TagValue, "Player1"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Black"}, - {TagValue, "Player2"}, - {TagEnd, "]"}, - {TagStart, "["}, - {TagKey, "Result"}, - {TagValue, "1-0"}, - {TagEnd, "]"}, - {MoveNumber, "1"}, - {DOT, "."}, - {SQUARE, "e4"}, - {SQUARE, "e5"}, - {MoveNumber, "2"}, - {DOT, "."}, - {PIECE, "N"}, - {SQUARE, "f3"}, - {PIECE, "N"}, - {SQUARE, "c6"}, - {MoveNumber, "3"}, - {DOT, "."}, - {PIECE, "B"}, - {SQUARE, "b5"}, - {CommentStart, "{"}, - {COMMENT, "This is the Ruy Lopez."}, - {CommentEnd, "}"}, - {MoveNumber, "3"}, - {ELLIPSIS, "..."}, - {SQUARE, "a6"}, - {RESULT, "1-0"}, - } - - if len(tokens) != len(expectedFirstGame) { - t.Errorf("Expected %d tokens, got %d", len(expectedFirstGame), len(tokens)) - return - } - - for i, expected := range expectedFirstGame { - if i >= len(tokens) { - t.Errorf("Missing token at position %d, expected {%v, %q}", i, expected.typ, expected.value) - continue - } - - if tokens[i].Type != expected.typ || tokens[i].Value != expected.value { - t.Errorf("Token %d - Expected {%v, %q}, got {%v, %q}", - i, expected.typ, expected.value, tokens[i].Type, tokens[i].Value) - } - } - - // Test second game (if exists) - _, err = scanner.ScanGame() - if err != nil && !errors.Is(err, io.EOF) { - t.Errorf("Unexpected error reading second game: %v", err) - } - - // Test HasNext functionality by counting games - file.Seek(0, 0) // Reset file to beginning - scanner = NewScanner(file) - - var gameCount int - for scanner.HasNext() { - game, err := scanner.ScanGame() - if err != nil { - t.Fatalf("Error reading game %d: %v", gameCount+1, err) - } - - tokens, err = TokenizeGame(game) - if err != nil { - t.Fatalf("Error tokenizing game %d: %v", gameCount+1, err) - } - - if len(tokens) == 0 { - t.Errorf("Game %d has no tokens", gameCount+1) - } - - gameCount++ - } - - expectedGames := 4 - if gameCount != expectedGames { - t.Errorf("Expected %d games, got %d", expectedGames, gameCount) - } -} - -func TestScannerEmptyFile(t *testing.T) { - tmpfile, err := os.CreateTemp("", "empty.pgn") - if err != nil { - t.Fatalf("Failed to create temp file: %v", err) - } - defer os.Remove(tmpfile.Name()) - defer tmpfile.Close() - - scanner := NewScanner(tmpfile) - - if scanner.HasNext() { - t.Error("Expected HasNext() to return false for empty file") - } - - game, err := scanner.ScanGame() - if !errors.Is(err, io.EOF) { - t.Errorf("Expected EOF error for empty file, got %v", err) - } - if game != nil { - t.Error("Expected nil game for empty file") - } -} - -func TestSequentialProcessing(t *testing.T) { - file, err := os.Open(filepath.Join("fixtures/pgns", "multi_game.pgn")) - if err != nil { - t.Fatalf("Failed to open fixture file: %v", err) - } - defer file.Close() - - scanner := NewScanner(file) - var games []*GameScanned - var allTokens [][]Token - - // Read all games using ScanGame in a loop - for { - game, err := scanner.ScanGame() - if errors.Is(err, io.EOF) { - break - } - if err != nil { - t.Fatalf("Failed to scan game: %v", err) - } - games = append(games, game) - - tokens, err := TokenizeGame(game) - if err != nil { - t.Fatalf("Failed to tokenize game: %v", err) - } - allTokens = append(allTokens, tokens) - } - - if len(games) != 4 { - t.Errorf("Expected 4 games, got %d", len(games)) - } - - for i, tokens := range allTokens { - if len(tokens) == 0 { - t.Errorf("Game %d has no tokens", i+1) - } - } -} - -// Additional test to verify HasNext doesn't consume games. -func TestHasNextDoesntConsume(t *testing.T) { - file, err := os.Open(filepath.Join("fixtures/pgns", "multi_game.pgn")) - if err != nil { - t.Fatalf("Failed to open fixture file: %v", err) - } - defer file.Close() - - scanner := NewScanner(file) - - // Call HasNext multiple times - for i := range 3 { - if !scanner.HasNext() { - t.Errorf("Expected HasNext() to return true on call %d", i+1) - } - } - - // Should still be able to read the first game - game, err := scanner.ScanGame() - if err != nil { - t.Fatalf("Failed to read first game after HasNext calls: %v", err) - } - - tokens, err := TokenizeGame(game) - if err != nil { - t.Fatalf("Failed to tokenize first game: %v", err) - } - - if len(tokens) == 0 { - t.Error("First game has no tokens after multiple HasNext calls") - } -} - -func validateExpand(t *testing.T, scanner *Scanner, expectedLastLines []string, - expectedFinalPos []string, -) { - count := 0 - for scanner.HasNext() { - game, err := scanner.ParseNext() - if err != nil { - t.Fatalf("fail to parse game %v: %s", count+1, err.Error()) - } - - if game == nil { - t.Fatalf("game is nil") - } - if count >= len(expectedLastLines) { - t.Fatalf("expected %v games but found at least %v", - len(expectedLastLines), count+1) - } - lines := strings.Split(game.String(), "\n") - if len(lines) == 0 { - t.Fatalf("split game %v output blank", count+1) - } - - lastLine := lines[len(lines)-1] - if lastLine != expectedLastLines[count] { - t.Errorf("game output not correct\n\tExpected:'%v'\n\tGot: '%v'\n", - expectedLastLines[count], lastLine) - } - fen := game.Position().XFENString() - if fen != expectedFinalPos[count] { - t.Errorf("game position not correct\n\tExpected:'%v'\n\tGot: '%v'\n", - expectedFinalPos[count], fen) - } - count++ - } - - if count != len(expectedLastLines) { - t.Fatalf("expected %v games but found only %v", - len(expectedLastLines), count) - } -} - -func TestScannerExpand(t *testing.T) { - expectedLastLines := []string{ - "1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Nxd4 *", - "1. e4 e5 2. Nc3 Nf6 3. f4 *", - "1. e4 d6 2. d4 Nf6 3. Nc3 e5 4. dxe5 dxe5 5. Qxd8+ Kxd8 *", - "1. e4 d6 2. d4 Nf6 3. Nc3 e5 4. Nf3 Nbd7 *", - "1. e3 e5 *", - } - expectedFinalPos := []string{ - "r1bqkbnr/pppp1ppp/2n5/8/3NP3/8/PPP2PPP/RNBQKB1R b KQkq - 0 4", - "rnbqkb1r/pppp1ppp/5n2/4p3/4PP2/2N5/PPPP2PP/R1BQKBNR b KQkq - 0 3", - "rnbk1b1r/ppp2ppp/5n2/4p3/4P3/2N5/PPP2PPP/R1B1KBNR w KQ - 0 6", - "r1bqkb1r/pppn1ppp/3p1n2/4p3/3PP3/2N2N2/PPP2PPP/R1BQKB1R w KQkq - 2 5", - "rnbqkbnr/pppp1ppp/8/4p3/8/4P3/PPPP1PPP/RNBQKBNR w KQkq - 0 2", - } - - pgn := mustParsePGN("fixtures/pgns/variations.pgn") - reader := strings.NewReader(pgn) - scanner := NewScanner(reader, WithExpandVariations()) - validateExpand(t, scanner, expectedLastLines, expectedFinalPos) -} - -func TestScannerNoExpand(t *testing.T) { - expectedLastLines := []string{ - "1. e4 (1. e3 e5) 1... e5 (1... d6 2. d4 Nf6 3. Nc3 e5 4. dxe5 (4. Nf3 Nbd7) 4... dxe5 5. Qxd8+ Kxd8) 2. Nf3 (2. Nc3 Nf6 3. f4) 2... Nc6 3. d4 exd4 4. Nxd4 *", - } - expectedFinalPos := []string{ - "r1bqkbnr/pppp1ppp/2n5/8/3NP3/8/PPP2PPP/RNBQKB1R b KQkq - 0 4", - } - - pgn := mustParsePGN("fixtures/pgns/variations.pgn") - reader := strings.NewReader(pgn) - scanner := NewScanner(reader) - validateExpand(t, scanner, expectedLastLines, expectedFinalPos) -} - -func TestScannerMultiFromPosNoExpand(t *testing.T) { - expectedLastLines := []string{ - "1. d4 d5 2. c4 c6 { [%eval 0.21]} *", - "3. Nf3 (3. Nc3 Nf6 4. Nf3) 3... Nf6 4. Nc3 { [%eval 0.16]} *", - "4... a6 { [%eval 0.19]} *", - "5. cxd5 (5. e3 e6 6. cxd5 cxd5) 5... cxd5 6. e3 e6 { [%eval 0.11]} *", - } - expectedFinalPos := []string{ - "rnbqkbnr/pp2pppp/2p5/3p4/2PP4/8/PP2PPPP/RNBQKBNR w KQkq - 0 3", - "rnbqkb1r/pp2pppp/2p2n2/3p4/2PP4/2N2N2/PP2PPPP/R1BQKB1R b KQkq - 3 4", - "rnbqkb1r/1p2pppp/p1p2n2/3p4/2PP4/2N2N2/PP2PPPP/R1BQKB1R w KQkq - 0 5", - "rnbqkb1r/1p3ppp/p3pn2/3p4/3P4/2N1PN2/PP3PPP/R1BQKB1R w KQkq - 0 7", - } - - pgn := mustParsePGN("fixtures/pgns/multi_frompos_games.pgn") - reader := strings.NewReader(pgn) - scanner := NewScanner(reader) - validateExpand(t, scanner, expectedLastLines, expectedFinalPos) -} - -func TestEscapedQuoteInTagValue(t *testing.T) { - const escapedQuoteGame = `[Event "Internet Section 08A g/8'+2\""] -[Site "Dos Hermanas"] -[Date "2004.03.08"] -[Round "6"] -[White "Di Berardino, Diego Rafael"] -[Black "Mar, Fernando"] -[Result "1/2-1/2"] -[ECO "B96"] - -1. e4 c5 2. Nf3 1/2-1/2 -` - - scanner := NewScanner(strings.NewReader(escapedQuoteGame)) - if !scanner.HasNext() { - t.Fatal("scanner should report one game") - } - game, err := scanner.ParseNext() - if err != nil { - t.Fatalf("BUG: parser rejects spec-legal escaped quote in tag value: %v", err) - } - - // The in-memory value should contain a literal double quote. - if game.GetTagPair("Event") != `Internet Section 08A g/8'+2"` { - t.Fatalf("expected unescaped quote in tag value, got %q", game.GetTagPair("Event")) - } - - // Round-trip: String() must emit the escaped form again. - pgn := game.String() - if !strings.Contains(pgn, `[Event "Internet Section 08A g/8'+2\""]`) { - t.Fatalf("round-trip PGN does not contain escaped quote: %s", pgn) - } -} diff --git a/setup.go b/setup.go new file mode 100644 index 00000000..147b77b5 --- /dev/null +++ b/setup.go @@ -0,0 +1,411 @@ +package chess + +import ( + "errors" + "fmt" + "math/bits" +) + +// Variant identifies the starting-position variant of a position. The zero +// value is Standard. Chess960 (Fischer Random Chess) selects one of 960 +// indexed initial back-rank arrangements; its castling rights and rook origins +// differ from standard chess but its castling destinations do not. +type Variant int8 + +const ( + // Standard is the standard chess starting position. + Standard Variant = iota + // Chess960 is the Fischer Random Chess variant (960 indexed starts). + Chess960 +) + +// String returns the variant's canonical name. +func (v Variant) String() string { + switch v { + case Standard: + return "Standard" + case Chess960: + return "Chess960" + } + return "Standard" +} + +// Setup is an unvalidated description of a chess position. It separates +// "describing a position" from "playing a position" by letting callers build a +// complete position representation and then asking NewPosition to validate it. +type Setup struct { + Board Board + Turn Color + CastleRights CastleRights + EnPassant Square + HalfMoveClock int + FullMoveNo int + Variant Variant +} + +// EmptySetup returns a Setup representing an empty board: no pieces, White to +// move, no castling rights, no en passant square, halfmove clock 0, fullmove 1. +// It is the zero position used as a starting point for construction. +func EmptySetup() Setup { + return Setup{Turn: White, EnPassant: NoSquare, FullMoveNo: 1} +} + +// InitialSetup returns a Setup representing the standard chess starting +// position. The returned value is a copy and safe for callers to mutate. +func InitialSetup() Setup { + return startingSetup +} + +// SwapTurn returns a copy of s with the side to move flipped and the en +// passant square cleared. Halfmove clock and fullmove number are preserved. +// This is the FIDE "pass" semantic used for repetition detection: only the +// side to move and en passant rights change, not the move counters. +func (s Setup) SwapTurn() Setup { + return Setup{ + Board: s.Board, + Turn: s.Turn.Other(), + CastleRights: s.CastleRights, + EnPassant: NoSquare, + HalfMoveClock: s.HalfMoveClock, + FullMoveNo: s.FullMoveNo, + Variant: s.Variant, + } +} + +// Mirror returns a vertically mirrored copy of s: every piece swaps color and +// moves to the square on the same file but the opposite rank (rank 1 ↔ rank 8); +// the side to move flips; castling rights swap color; the en passant square +// moves to the opposite rank. Halfmove clock and fullmove number are preserved. +// +// Useful for opening-book authors who want to reuse one side's analysis for +// the other, and for symmetric position testing. Mirroring a legal standard +// position always produces a legal standard position. +func (s Setup) Mirror() Setup { + m := make(map[Square]Piece, numOfSquaresInBoard) + for sq := range numOfSquaresInBoard { + p := s.Board.Piece(Square(sq)) + if p == NoPiece { + continue + } + file := Square(sq).File() + rank := 7 - Square(sq).Rank() + m[NewSquare(file, rank)] = NewPiece(p.Type(), p.Color().Other()) + } + b, err := NewBoard(m) + if err != nil { + // Mirror of a valid board cannot produce an invalid board: every + // occupied square maps to a distinct occupied square. + panic(fmt.Sprintf("chess: mirror produced invalid board: %v", err)) + } + cr := NewCastleRights( + s.CastleRights.CanCastle(Black, KingSide), + s.CastleRights.CanCastle(Black, QueenSide), + s.CastleRights.CanCastle(White, KingSide), + s.CastleRights.CanCastle(White, QueenSide), + ) + ep := NoSquare + if s.EnPassant != NoSquare { + ep = NewSquare(s.EnPassant.File(), 7-s.EnPassant.Rank()) + } + return Setup{ + Board: *b, + Turn: s.Turn.Other(), + CastleRights: cr, + EnPassant: ep, + HalfMoveClock: s.HalfMoveClock, + FullMoveNo: s.FullMoveNo, + Variant: s.Variant, + } +} + +// startingSetup is the setup that corresponds to the standard starting +// position. It is kept unexported because callers should normally use +// StartingPosition(); it exists primarily for tests of NewPosition. +var startingSetup = func() Setup { + b, err := fenBoard("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR") + if err != nil { + panic(err) + } + return Setup{ + Board: *b, + Turn: White, + CastleRights: NewCastleRights(true, true, true, true), + EnPassant: NoSquare, + HalfMoveClock: 0, + FullMoveNo: 1, + } +}() + +// NewPosition validates s and constructs a playable Position from it. +// +// Validation covers: +// - exactly one king of each color +// - no pawns on the first or eighth rank +// - castling rights that match the king and rook placement on their starting +// squares +// - an en passant square that is consistent with a pawn that just moved two +// squares +// - non-negative halfmove clock and positive fullmove number +func NewPosition(s Setup) (*Position, error) { + if err := validateSetup(&s); err != nil { + return nil, err + } + + pos := &Position{ + board: s.Board, + turn: s.Turn, + castleRights: s.CastleRights, + enPassantSquare: s.EnPassant, + halfMoveClock: s.HalfMoveClock, + moveCount: s.FullMoveNo, + variant: s.Variant, + } + pos.inCheck, pos.checkers = checkState(pos) + pos.hash = pos.computeHash() + return pos, nil +} + +func validateSetup(s *Setup) error { + if s.HalfMoveClock < 0 { + return errors.New("chess: setup: halfmove clock cannot be negative") + } + if s.FullMoveNo < 1 { + return errors.New("chess: setup: fullmove number must be at least 1") + } + + whiteKings := bits.OnesCount64(uint64(s.Board.bbWhiteKing)) + blackKings := bits.OnesCount64(uint64(s.Board.bbBlackKing)) + if whiteKings != 1 { + return fmt.Errorf("chess: setup: expected exactly one white king, got %d", whiteKings) + } + if blackKings != 1 { + return fmt.Errorf("chess: setup: expected exactly one black king, got %d", blackKings) + } + + for file := FileA; file <= FileH; file++ { + if p := s.Board.Piece(NewSquare(file, Rank1)); p.Type() == Pawn { + return fmt.Errorf("chess: setup: pawn on %s", NewSquare(file, Rank1)) + } + if p := s.Board.Piece(NewSquare(file, Rank8)); p.Type() == Pawn { + return fmt.Errorf("chess: setup: pawn on %s", NewSquare(file, Rank8)) + } + } + + if s.Variant == Chess960 { + if err := validateChess960CastleRights(s); err != nil { + return err + } + } else { + if s.CastleRights.CanCastle(White, KingSide) && + (s.Board.Piece(E1) != WhiteKing || s.Board.Piece(H1) != WhiteRook) { + return errors.New("chess: setup: white kingside castling rights inconsistent with board") + } + if s.CastleRights.CanCastle(White, QueenSide) && + (s.Board.Piece(E1) != WhiteKing || s.Board.Piece(A1) != WhiteRook) { + return errors.New("chess: setup: white queenside castling rights inconsistent with board") + } + if s.CastleRights.CanCastle(Black, KingSide) && + (s.Board.Piece(E8) != BlackKing || s.Board.Piece(H8) != BlackRook) { + return errors.New("chess: setup: black kingside castling rights inconsistent with board") + } + if s.CastleRights.CanCastle(Black, QueenSide) && + (s.Board.Piece(E8) != BlackKing || s.Board.Piece(A8) != BlackRook) { + return errors.New("chess: setup: black queenside castling rights inconsistent with board") + } + } + + if s.EnPassant != NoSquare { + switch s.Turn { + case White: + if s.EnPassant.Rank() != Rank6 { + return fmt.Errorf("chess: setup: en passant square %s inconsistent with side to move White", s.EnPassant) + } + if s.Board.Piece(s.EnPassant-8) != BlackPawn { + return fmt.Errorf("chess: setup: no black pawn on %s for en passant %s", s.EnPassant-8, s.EnPassant) + } + case Black: + if s.EnPassant.Rank() != Rank3 { + return fmt.Errorf("chess: setup: en passant square %s inconsistent with side to move Black", s.EnPassant) + } + if s.Board.Piece(s.EnPassant+8) != WhitePawn { + return fmt.Errorf("chess: setup: no white pawn on %s for en passant %s", s.EnPassant+8, s.EnPassant) + } + } + } + + return nil +} + +// Chess960Setup returns the Setup for the Chess960 starting position with the +// given Scharnagl index (0-959). The index selects one of 960 initial back-rank +// arrangements satisfying the Chess960 constraints: bishops on opposite-colored +// squares and the king placed between the two rooks. Index 518 is the standard +// starting position. The returned Setup has Variant Chess960 and full castling +// rights for both sides. +func Chess960Setup(index int) (Setup, error) { + if index < 0 || index > 959 { + return Setup{}, fmt.Errorf("chess: chess960 start index %d out of range [0, 959]", index) + } + + // Scharnagl decomposition over the eight files of rank 1. + const ( + lightFiles = "bdfh" // files 1, 3, 5, 7 (opposite color to "aceg") + darkFiles = "aceg" // files 0, 2, 4, 6 + ) + var back [8]Piece // white back rank, indexed by file 0..7 + used := [8]bool{} + + n := index + + // First bishop: one of the four light-square files. + b1 := n % 4 + n /= 4 + f := int(lightFiles[b1] - 'a') + back[f] = WhiteBishop + used[f] = true + + // Second bishop: one of the four dark-square files. + b2 := n % 4 + n /= 4 + f = int(darkFiles[b2] - 'a') + back[f] = WhiteBishop + used[f] = true + + // Queen: the n%6-th remaining empty file. + q := n % 6 + n /= 6 + cnt := 0 + for i := range 8 { + if !used[i] { + if cnt == q { + back[i] = WhiteQueen + used[i] = true + break + } + cnt++ + } + } + + // Knights: the n-th pair (0..9) of the five remaining empty files. + var rem [5]int + ri := 0 + for i := range 8 { + if !used[i] { + rem[ri] = i + ri++ + } + } + pair := 0 + for i := range 4 { + for j := i + 1; j < 5; j++ { + if pair == n { + back[rem[i]] = WhiteKnight + back[rem[j]] = WhiteKnight + used[rem[i]] = true + used[rem[j]] = true + } + pair++ + } + } + + // Remaining three files receive Rook, King, Rook in increasing file order, + // placing the king between the two rooks. + var last [3]int + li := 0 + for i := range 8 { + if !used[i] { + last[li] = i + li++ + } + } + back[last[0]] = WhiteRook + back[last[1]] = WhiteKing + back[last[2]] = WhiteRook + + // Assemble the full board: white back rank on rank 1, black mirrored on + // rank 8 (same file, opposite color), pawns on ranks 2 and 7. + m := make(map[Square]Piece, 32) + for file := range 8 { + wp := back[file] + m[NewSquare(File(file), Rank1)] = wp + m[NewSquare(File(file), Rank8)] = NewPiece(wp.Type(), Black) + m[NewSquare(File(file), Rank2)] = WhitePawn + m[NewSquare(File(file), Rank7)] = BlackPawn + } + b, err := NewBoard(m) + if err != nil { + return Setup{}, fmt.Errorf("chess: chess960 start %d: %w", index, err) + } + + return Setup{ + Board: *b, + Turn: White, + CastleRights: NewCastleRights(true, true, true, true), + EnPassant: NoSquare, + HalfMoveClock: 0, + FullMoveNo: 1, + Variant: Chess960, + }, nil +} + +// validateChess960CastleRights checks that castling rights are consistent with +// the board for a Chess960 position. A held right requires the side's king on +// its back rank and, for the king side, a rook somewhere to the king's right +// (higher file); for the queen side, a rook to the king's left (lower file). +// Unlike standard chess the king and rooks need not occupy fixed squares. +func validateChess960CastleRights(s *Setup) error { + for _, c := range []Color{White, Black} { + var ( + rank Rank + kingPiece Piece + rookPiece Piece + ) + if c == White { + rank, kingPiece, rookPiece = Rank1, WhiteKing, WhiteRook + } else { + rank, kingPiece, rookPiece = Rank8, BlackKing, BlackRook + } + + kingSide := s.CastleRights.CanCastle(c, KingSide) + queenSide := s.CastleRights.CanCastle(c, QueenSide) + if !kingSide && !queenSide { + continue + } + + kingFile := -1 + for f := range 8 { + if s.Board.Piece(NewSquare(File(f), rank)) == kingPiece { + kingFile = f + break + } + } + if kingFile < 0 { + return fmt.Errorf("chess: setup: %s castling rights require the %s king on its back rank", c.Name(), c.Name()) + } + if kingSide { + ok := false + for f := kingFile + 1; f < 8; f++ { + if s.Board.Piece(NewSquare(File(f), rank)) == rookPiece { + ok = true + break + } + } + if !ok { + return fmt.Errorf("chess: setup: %s kingside castling rights require a rook to the king's right", c.Name()) + } + } + if queenSide { + ok := false + for f := kingFile - 1; f >= 0; f-- { + if s.Board.Piece(NewSquare(File(f), rank)) == rookPiece { + ok = true + break + } + } + if !ok { + return fmt.Errorf("chess: setup: %s queenside castling rights require a rook to the king's left", c.Name()) + } + } + } + return nil +} diff --git a/setup_test.go b/setup_test.go new file mode 100644 index 00000000..db412a5e --- /dev/null +++ b/setup_test.go @@ -0,0 +1,219 @@ +package chess + +import ( + "strings" + "testing" +) + +func TestNewPositionStartingSetup(t *testing.T) { + got, err := NewPosition(startingSetup) + if err != nil { + t.Fatalf("NewPosition(startingSetup): %v", err) + } + want := StartingPosition() + if got.String() != want.String() { + t.Errorf("FEN mismatch:\n got %s\n want %s", got.String(), want.String()) + } + if got.ZobristHash() != want.ZobristHash() { + t.Errorf("Zobrist hash mismatch: got %x, want %x", got.ZobristHash(), want.ZobristHash()) + } +} + +func TestNewPositionRejectsInvalidSetups(t *testing.T) { + cases := []struct { + name string + setup Setup + wantErr string + }{ + { + name: "missing white king", + setup: func() Setup { + b, _ := fenBoard("4k3/8/8/8/8/8/8/8") + return Setup{Board: *b, Turn: White, FullMoveNo: 1} + }(), + wantErr: "white king", + }, + { + name: "missing black king", + setup: func() Setup { + b, _ := fenBoard("8/8/8/8/8/8/8/4K3") + return Setup{Board: *b, Turn: White, FullMoveNo: 1} + }(), + wantErr: "black king", + }, + { + name: "pawn on first rank", + setup: func() Setup { + b, _ := fenBoard("4k3/8/8/8/8/8/8/P3K3") + return Setup{Board: *b, Turn: White, FullMoveNo: 1} + }(), + wantErr: "pawn on a1", + }, + { + name: "pawn on eighth rank", + setup: func() Setup { + b, _ := fenBoard("4k2p/8/8/8/8/8/8/4K3") + return Setup{Board: *b, Turn: White, FullMoveNo: 1} + }(), + wantErr: "pawn on h8", + }, + { + name: "castling rights without rook", + setup: func() Setup { + b, _ := fenBoard("4k3/8/8/8/8/8/8/4K3") + return Setup{Board: *b, Turn: White, CastleRights: NewCastleRights(true, false, false, false), FullMoveNo: 1} + }(), + wantErr: "white kingside castling rights", + }, + { + name: "en passant square without pawn", + setup: func() Setup { + b, _ := fenBoard("4k3/8/8/8/8/8/8/4K3") + return Setup{Board: *b, Turn: Black, EnPassant: D3, FullMoveNo: 1} + }(), + wantErr: "white pawn on d4", + }, + { + name: "negative halfmove clock", + setup: func() Setup { + b, _ := fenBoard("4k3/8/8/8/8/8/8/4K3") + return Setup{Board: *b, Turn: White, HalfMoveClock: -1, FullMoveNo: 1} + }(), + wantErr: "halfmove clock", + }, + { + name: "zero fullmove number", + setup: func() Setup { + b, _ := fenBoard("4k3/8/8/8/8/8/8/4K3") + return Setup{Board: *b, Turn: White, FullMoveNo: 0} + }(), + wantErr: "fullmove number", + }, + } + + for _, tc := range cases { + t.Run(tc.name, func(t *testing.T) { + _, err := NewPosition(tc.setup) + if err == nil { + t.Fatal("expected error, got nil") + } + if !strings.Contains(err.Error(), tc.wantErr) { + t.Errorf("error %q does not contain %q", err.Error(), tc.wantErr) + } + }) + } +} + +func TestDecodeFENRoundsThroughNewPosition(t *testing.T) { + _, err := decodeFEN("4k3/8/8/8/8/8/8/4K2R w KQ - 0 1") + if err == nil { + t.Fatal("expected decodeFEN to reject inconsistent white queenside rights") + } + if !strings.Contains(err.Error(), "white queenside castling rights") { + t.Errorf("error %q does not mention white queenside castling rights", err.Error()) + } +} + +func TestEmptySetup(t *testing.T) { + s := EmptySetup() + // EmptySetup is a construction starting point, not a playable position: + // it has no kings, so NewPosition must reject it. + if _, err := NewPosition(s); err == nil { + t.Fatal("NewPosition(EmptySetup()) = nil, want error (no kings)") + } + if got := s.Board.Piece(A1); got != NoPiece { + t.Errorf("EmptySetup().Board.Piece(A1) = %v, want NoPiece", got) + } + if s.Turn != White { + t.Errorf("EmptySetup().Turn = %v, want White", s.Turn) + } + if s.EnPassant != NoSquare { + t.Errorf("EmptySetup().EnPassant = %v, want NoSquare", s.EnPassant) + } + if s.HalfMoveClock != 0 { + t.Errorf("EmptySetup().HalfMoveClock = %d, want 0", s.HalfMoveClock) + } + if s.FullMoveNo != 1 { + t.Errorf("EmptySetup().FullMoveNo = %d, want 1", s.FullMoveNo) + } +} + +func TestInitialSetup(t *testing.T) { + s := InitialSetup() + pos, err := NewPosition(s) + if err != nil { + t.Fatalf("NewPosition(InitialSetup()): %v", err) + } + if got, want := pos.String(), StartingPosition().String(); got != want { + t.Errorf("InitialSetup() FEN = %q, want %q", got, want) + } +} + +func TestSetupSwapTurn(t *testing.T) { + s := InitialSetup() + swapped := s.SwapTurn() + if swapped.Turn != Black { + t.Errorf("SwapTurn().Turn = %v, want Black", swapped.Turn) + } + if swapped.EnPassant != NoSquare { + t.Errorf("SwapTurn().EnPassant = %v, want NoSquare", swapped.EnPassant) + } + // Original is not mutated. + if s.Turn != White { + t.Errorf("original Setup.Turn mutated: %v", s.Turn) + } + // SwapTurn is its own inverse for the turn field. + if back := swapped.SwapTurn(); back.Turn != White { + t.Errorf("SwapTurn().SwapTurn().Turn = %v, want White", back.Turn) + } +} + +func TestSetupMirror(t *testing.T) { + s := InitialSetup() + m := s.Mirror() + // The mirrored starting position is still a legal starting position: + // pieces are on the same squares but swapped in color, and since the + // starting position is color-symmetric, the FEN must round-trip. + if m.Turn != Black { + t.Errorf("Mirror().Turn = %v, want Black", m.Turn) + } + pos, err := NewPosition(m) + if err != nil { + t.Fatalf("NewPosition(Mirror()): %v", err) + } + // White king on e1 becomes black king on e8 (and vice versa). + if got := m.Board.Piece(E8); got.Type() != King || got.Color() != Black { + t.Errorf("Mirror().Board.Piece(E8) = %v, want Black King", got) + } + if got := m.Board.Piece(E1); got.Type() != King || got.Color() != White { + t.Errorf("Mirror().Board.Piece(E1) = %v, want White King", got) + } + _ = pos +} + +func TestSetupMirrorEnPassant(t *testing.T) { + // Black just played e7-e5; en passant target is e6. + s := Setup{ + Board: mustBoard(t, "rnbqkbnr/pppp1ppp/8/4p3/8/8/PPPPPPPP/RNBQKBNR"), + Turn: White, + EnPassant: E6, + CastleRights: NewCastleRights(true, true, true, true), + FullMoveNo: 1, + } + m := s.Mirror() + if m.EnPassant != E3 { + t.Errorf("Mirror().EnPassant = %v, want E3 (e6 mirrored to e3)", m.EnPassant) + } + if m.Turn != Black { + t.Errorf("Mirror().Turn = %v, want Black", m.Turn) + } +} + +func mustBoard(t *testing.T, boardFEN string) Board { + t.Helper() + b, err := fenBoard(boardFEN) + if err != nil { + t.Fatalf("fenBoard(%q): %v", boardFEN, err) + } + return *b +} diff --git a/square.go b/square.go index 8a1b8013..b57f4267 100644 --- a/square.go +++ b/square.go @@ -1,5 +1,7 @@ package chess +import "fmt" + const ( numOfSquaresInBoard = 64 numOfSquaresInRow = 8 @@ -22,8 +24,8 @@ func (sq Square) String() string { return sq.File().String() + sq.Rank().String() } -func (sq Square) Bytes() []byte { - return []byte{sq.File().Byte(), sq.Rank().Byte()} +func (sq Square) Bytes() [2]byte { + return [2]byte{sq.File().Byte(), sq.Rank().Byte()} } // NewSquare creates a new Square from a File and a Rank. @@ -155,139 +157,26 @@ func (f File) Byte() byte { return fileChars[f] } +// ParseSquare converts a 2-character square notation (e.g., "e4") to a Square. +// It returns an error if the input is not a valid square. +func ParseSquare(s string) (Square, error) { + if len(s) != 2 { + return NoSquare, fmt.Errorf("chess: invalid square %q", s) + } + f := int(s[0] - 'a') + r := int(s[1] - '1') + if f < 0 || f > 7 || r < 0 || r > 7 { + return NoSquare, fmt.Errorf("chess: invalid square %q", s) + } + return NewSquare(File(f), Rank(r)), nil +} + // SquareFromString converts a 2-character square notation (e.g., "e4") to a Square. // Returns NoSquare if the string is not a valid square. +// +// Deprecated: use ParseSquare for new code; it distinguishes parse failures from +// the NoSquare sentinel. func SquareFromString(s string) Square { - switch s { - case "a1": - return A1 - case "a2": - return A2 - case "a3": - return A3 - case "a4": - return A4 - case "a5": - return A5 - case "a6": - return A6 - case "a7": - return A7 - case "a8": - return A8 - case "b1": - return B1 - case "b2": - return B2 - case "b3": - return B3 - case "b4": - return B4 - case "b5": - return B5 - case "b6": - return B6 - case "b7": - return B7 - case "b8": - return B8 - case "c1": - return C1 - case "c2": - return C2 - case "c3": - return C3 - case "c4": - return C4 - case "c5": - return C5 - case "c6": - return C6 - case "c7": - return C7 - case "c8": - return C8 - case "d1": - return D1 - case "d2": - return D2 - case "d3": - return D3 - case "d4": - return D4 - case "d5": - return D5 - case "d6": - return D6 - case "d7": - return D7 - case "d8": - return D8 - case "e1": - return E1 - case "e2": - return E2 - case "e3": - return E3 - case "e4": - return E4 - case "e5": - return E5 - case "e6": - return E6 - case "e7": - return E7 - case "e8": - return E8 - case "f1": - return F1 - case "f2": - return F2 - case "f3": - return F3 - case "f4": - return F4 - case "f5": - return F5 - case "f6": - return F6 - case "f7": - return F7 - case "f8": - return F8 - case "g1": - return G1 - case "g2": - return G2 - case "g3": - return G3 - case "g4": - return G4 - case "g5": - return G5 - case "g6": - return G6 - case "g7": - return G7 - case "g8": - return G8 - case "h1": - return H1 - case "h2": - return H2 - case "h3": - return H3 - case "h4": - return H4 - case "h5": - return H5 - case "h6": - return H6 - case "h7": - return H7 - case "h8": - return H8 - default: - return NoSquare - } + sq, _ := ParseSquare(s) + return sq } diff --git a/square_test.go b/square_test.go index 6f60d4fb..cffbfab5 100644 --- a/square_test.go +++ b/square_test.go @@ -1,29 +1,194 @@ -package chess +package chess_test -import "testing" +import ( + "testing" -type newSquareTest struct { - f File - r Rank - sq Square + "github.com/corentings/chess/v3" +) + +func TestNewSquare_FromFileAndRank(t *testing.T) { + t.Parallel() + tests := []struct { + name string + f chess.File + r chess.Rank + want chess.Square + }{ + {"a1", chess.FileA, chess.Rank1, chess.A1}, + {"a8", chess.FileA, chess.Rank8, chess.A8}, + {"h1", chess.FileH, chess.Rank1, chess.H1}, + {"h8", chess.FileH, chess.Rank8, chess.H8}, + {"b4", chess.FileB, chess.Rank4, chess.B4}, + {"e8", chess.FileE, chess.Rank8, chess.E8}, + {"h3", chess.FileH, chess.Rank3, chess.H3}, + {"d7", chess.FileD, chess.Rank7, chess.D7}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + if got := chess.NewSquare(tt.f, tt.r); got != tt.want { + t.Errorf("NewSquare(%v,%v) = %s, want %s", tt.f, tt.r, got.String(), tt.want.String()) + } + }) + } +} + +func TestNewSquare_RoundTripsThroughFileAndRank(t *testing.T) { + t.Parallel() + for _, sq := range allSquares() { + t.Run(sq.String(), func(t *testing.T) { + t.Parallel() + if got := chess.NewSquare(sq.File(), sq.Rank()); got != sq { + t.Errorf("NewSquare(%s.File(), %s.Rank()) = %s, want %s", sq, sq, got, sq) + } + }) + } +} + +func TestSquare_StringRoundTrip(t *testing.T) { + t.Parallel() + for _, sq := range allSquares() { + t.Run(sq.String(), func(t *testing.T) { + t.Parallel() + got, err := chess.ParseSquare(sq.String()) + if err != nil { + t.Fatalf("ParseSquare(%q): %v", sq.String(), err) + } + if got != sq { + t.Errorf("ParseSquare(%q) = %v, want %v", sq.String(), got, sq) + } + }) + } } -func TestNewSquare(t *testing.T) { - testCases := []newSquareTest{ - {FileA, Rank1, A1}, - {FileA, Rank8, A8}, - {FileH, Rank1, H1}, - {FileH, Rank8, H8}, - {FileB, Rank4, B4}, - {FileE, Rank8, E8}, - {FileH, Rank3, H3}, - {FileD, Rank7, D7}, +func TestSquare_Bytes(t *testing.T) { + t.Parallel() + for _, sq := range allSquares() { + t.Run(sq.String(), func(t *testing.T) { + t.Parallel() + b := sq.Bytes() + if len(b) != 2 { + t.Fatalf("%s.Bytes() len = %d, want 2", sq, len(b)) + } + if string(b[:]) != sq.String() { + t.Errorf("%s.Bytes() = %q, want %q", sq, string(b[:]), sq.String()) + } + }) + } +} + +func TestParseSquare(t *testing.T) { + t.Parallel() + valid := []struct { + in string + want chess.Square + }{ + {"a1", chess.A1}, + {"a8", chess.A8}, + {"h1", chess.H1}, + {"h8", chess.H8}, + {"e4", chess.E4}, + {"d1", chess.D1}, + {"g5", chess.G5}, + } + for _, tt := range valid { + t.Run("valid/"+tt.in, func(t *testing.T) { + t.Parallel() + got, err := chess.ParseSquare(tt.in) + if err != nil { + t.Fatalf("ParseSquare(%q): %v", tt.in, err) + } + if got != tt.want { + t.Errorf("ParseSquare(%q) = %v, want %v", tt.in, got, tt.want) + } + }) + } + invalid := []string{"", "a", "a9", "a0", "i1", "z9", "A1", "e44", " e4", "e4 ", "##", "e"} + for _, in := range invalid { + t.Run("invalid/"+in, func(t *testing.T) { + t.Parallel() + if got, err := chess.ParseSquare(in); err == nil { + t.Errorf("ParseSquare(%q) = %v, want error", in, got) + } + }) } +} + +func TestFile_StringAndByte(t *testing.T) { + t.Parallel() + tests := []struct { + name string + f chess.File + str string + b byte + }{ + {"file_a", chess.FileA, "a", 'a'}, + {"file_b", chess.FileB, "b", 'b'}, + {"file_c", chess.FileC, "c", 'c'}, + {"file_d", chess.FileD, "d", 'd'}, + {"file_e", chess.FileE, "e", 'e'}, + {"file_f", chess.FileF, "f", 'f'}, + {"file_g", chess.FileG, "g", 'g'}, + {"file_h", chess.FileH, "h", 'h'}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + if got := tt.f.String(); got != tt.str { + t.Errorf("String() = %q, want %q", got, tt.str) + } + if got := tt.f.Byte(); got != tt.b { + t.Errorf("Byte() = %q, want %q", got, tt.b) + } + }) + } +} + +func TestRank_StringAndByte(t *testing.T) { + t.Parallel() + tests := []struct { + name string + r chess.Rank + str string + b byte + }{ + {"rank_1", chess.Rank1, "1", '1'}, + {"rank_2", chess.Rank2, "2", '2'}, + {"rank_3", chess.Rank3, "3", '3'}, + {"rank_4", chess.Rank4, "4", '4'}, + {"rank_5", chess.Rank5, "5", '5'}, + {"rank_6", chess.Rank6, "6", '6'}, + {"rank_7", chess.Rank7, "7", '7'}, + {"rank_8", chess.Rank8, "8", '8'}, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + t.Parallel() + if got := tt.r.String(); got != tt.str { + t.Errorf("String() = %q, want %q", got, tt.str) + } + if got := tt.r.Byte(); got != tt.b { + t.Errorf("Byte() = %q, want %q", got, tt.b) + } + }) + } +} + +func TestNoSquare_IsMinusOne(t *testing.T) { + if chess.NoSquare != -1 { + t.Errorf("NoSquare = %d, want -1", chess.NoSquare) + } + if got, err := chess.ParseSquare("not-a-square"); err == nil { + t.Errorf("ParseSquare(invalid) = %v, want error", got) + } +} - for _, testCase := range testCases { - square := NewSquare(testCase.f, testCase.r) - if square != testCase.sq { - t.Fatalf("expected %s, got %s", testCase.sq.String(), square.String()) +func allSquares() []chess.Square { + squares := make([]chess.Square, 0, 64) + for r := chess.Rank1; r <= chess.Rank8; r++ { + for f := chess.FileA; f <= chess.FileH; f++ { + squares = append(squares, chess.NewSquare(f, r)) } } + return squares } diff --git a/uci/README.md b/uci/README.md index 990aa703..fe6220ba 100644 --- a/uci/README.md +++ b/uci/README.md @@ -69,4 +69,20 @@ func main() { // Output: // 1.c4 c5 2.Nf3 e6 3.Nc3 Nc6 4.d4 cxd4 5.Nxd4 Nf6 6.a3 d5 7.cxd5 exd5 8.Bf4 Bc5 9.Ndb5 O-O 10.Nc7 d4 11.Na4 Be7 12.Nxa8 Bf5 13.g3 Qd5 14.f3 Rxa8 15.Bg2 Rd8 16.b4 Qe6 17.Nc5 Bxc5 18.bxc5 Nd5 19.O-O Nc3 20.Qd2 Nxe2+ 21.Kh1 d3 22.Bd6 Qd7 23.Rab1 h6 24.a4 Re8 25.g4 Bg6 26.a5 Ncd4 27.Qb4 Qe6 28.Qxb7 Nc2 29.Qxa7 Ne3 30.Rb8 Nxf1 31.Qb6 d2 32.Rxe8+ Qxe8 33.Qb3 Ne3 34.h3 Bc2 35.Qxc2 Nxc2 36.Kh2 d1=Q 37.h4 Qg1+ 38.Kh3 Ne1 39.h5 Qxg2+ 40.Kh4 Nxf3# 0-1 } +``` + +## Chess960 + +Chess960 (Fischer Random) works without extra configuration. When a +`CmdPosition` carries a Chess960 position, the engine enables its +`UCI_Chess960` option automatically (if it advertised one in its `uci` +response), and castling is sent and read in the king-to-rook form +(`e1h1`) that the option specifies. A later standard position disables the +option again. Standard-chess traffic is unchanged. + +```go +setup, _ := chess.Chess960Setup(518) // SP-518 == the standard arrangement +pos, _ := chess.NewPosition(setup) // pos.Variant() == chess.Chess960 +// Sending this position enables UCI_Chess960 on the engine automatically. +eng.Run(uci.CmdPosition{Position: pos}) ``` \ No newline at end of file diff --git a/uci/adapter.go b/uci/adapter.go new file mode 100644 index 00000000..b528073b --- /dev/null +++ b/uci/adapter.go @@ -0,0 +1,98 @@ +package uci + +import ( + "bufio" + "errors" + "fmt" + "io" + "os/exec" +) + +// Adapter abstracts the transport layer between the Engine and a UCI process. +// Implementations send a command and return the engine's response lines. +type Adapter interface { + Exchange(cmd Cmd) ([]string, error) + Close() error +} + +// SubprocessAdapter is an Adapter that communicates with a UCI engine running +// as a subprocess via stdin/stdout pipes. +type SubprocessAdapter struct { + cmd *exec.Cmd + writer *io.PipeWriter + reader *io.PipeReader + scanner *bufio.Scanner +} + +// NewSubprocessAdapter locates the executable at the given path, starts it as a +// subprocess, and returns a SubprocessAdapter wired to its stdin/stdout. +func NewSubprocessAdapter(path string) (*SubprocessAdapter, error) { + path, err := exec.LookPath(path) + if err != nil { + return nil, fmt.Errorf("uci: executable not found at path %s %w", path, err) + } + rIn, wIn := io.Pipe() + rOut, wOut := io.Pipe() + cmd := exec.Command(path) //nolint:noctx // lifecycle is managed explicitly via Close() which kills the process + cmd.Stdin = rIn + cmd.Stdout = wOut + if err = cmd.Start(); err != nil { + _ = rIn.Close() + _ = wIn.Close() + _ = rOut.Close() + _ = wOut.Close() + return nil, fmt.Errorf("uci: failed to start executable %s: %w", path, err) + } + go func() { + _ = cmd.Wait() + }() + return &SubprocessAdapter{ + cmd: cmd, + writer: wIn, + reader: rOut, + scanner: bufio.NewScanner(rOut), + }, nil +} + +// Exchange sends a command to the engine and returns the response lines, or an +// error if communication fails. +func (s *SubprocessAdapter) Exchange(cmd Cmd) ([]string, error) { + if _, err := fmt.Fprintln(s.writer, cmd.String()); err != nil { + return nil, err + } + if cmd.IsDone("") { + return nil, nil + } + var lines []string + for s.scanner.Scan() { + line := s.scanner.Text() + lines = append(lines, line) + if cmd.IsDone(line) { + break + } + } + if err := s.scanner.Err(); err != nil { + return lines, err + } + return lines, nil +} + +// Close closes the communication pipes and kills the subprocess. +func (s *SubprocessAdapter) Close() error { + var errs []error + if s.writer != nil { + errs = append(errs, s.writer.Close()) + } + if s.reader != nil { + errs = append(errs, s.reader.Close()) + } + if s.cmd != nil && s.cmd.Process != nil { + errs = append(errs, s.cmd.Process.Kill()) + } + return errors.Join(errs...) +} + +// Pid returns the operating system process ID of the engine subprocess. +func (s *SubprocessAdapter) Pid() int { + return s.cmd.Process.Pid +} diff --git a/uci/adapter_test.go b/uci/adapter_test.go new file mode 100644 index 00000000..8559953c --- /dev/null +++ b/uci/adapter_test.go @@ -0,0 +1,577 @@ +package uci_test + +import ( + "bytes" + "log" + "strings" + "testing" + + "github.com/corentings/chess/v3" + "github.com/corentings/chess/v3/uci" +) + +func Test_FakeAdapter_ExchangeEmptyCommand(t *testing.T) { + emptyCmd := fakeEmptyCmd{} + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "": {"ignored"}, + "go": {"bestmove e2e4"}, + }, + } + t.Run("explicit empty key configured", func(t *testing.T) { + lines, err := fake.Exchange(emptyCmd) + if err != nil { + t.Fatalf("Exchange returned error: %v", err) + } + if len(lines) != 1 || lines[0] != "ignored" { + t.Errorf("expected canned response for empty key, got %v", lines) + } + }) + t.Run("unconfigured empty key returns nil", func(t *testing.T) { + fake2 := &uci.FakeAdapter{Responses: map[string][]string{}} + lines, err := fake2.Exchange(emptyCmd) + if err != nil { + t.Fatalf("Exchange returned error: %v", err) + } + if lines != nil { + t.Errorf("expected nil for unconfigured empty key, got %v", lines) + } + }) +} + +type fakeEmptyCmd struct{} + +func (fakeEmptyCmd) String() string { return "" } +func (fakeEmptyCmd) IsDone(_ string) bool { return false } +func (fakeEmptyCmd) LockRequired() bool { return false } +func (fakeEmptyCmd) Handle(_ []string, _ *uci.Engine) error { return nil } + +func Test_InfoUnmarshalText_WDLBounds(t *testing.T) { + tests := []struct { + name string + input string + wantErr bool + wantErrMsg string + }{ + { + name: "valid wdl with three values", + input: "info depth 24 seldepth 32 multipv 1 score cp 29 wdl 791 209 0 nodes 5130101 nps 819897", + wantErr: false, + }, + { + name: "truncated wdl missing draw and loss", + input: "info depth 24 score cp 29 wdl 791", + wantErr: true, + }, + { + name: "truncated wdl missing loss", + input: "info depth 24 score cp 29 wdl 791 209", + wantErr: true, + }, + { + name: "wdl non-integer value", + input: "info depth 24 score cp 29 wdl 791 x 0", + wantErr: true, + wantErrMsg: "uci: invalid info wdl draw", + }, + } + for _, tt := range tests { + t.Run(tt.name, func(t *testing.T) { + var info uci.Info + err := info.UnmarshalText([]byte(tt.input)) + if (err != nil) != tt.wantErr { + t.Fatalf("UnmarshalText(%q) err = %v, wantErr %v", tt.input, err, tt.wantErr) + } + if tt.wantErrMsg != "" && !strings.Contains(err.Error(), tt.wantErrMsg) { + t.Fatalf("UnmarshalText(%q) err = %v, want substring %q", tt.input, err, tt.wantErrMsg) + } + }) + } +} + +func Test_FakeAdapter_CmdUCI(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "uci": {"id name TestEngine", "id author test", "option name Hash type spin default 16 min 1 max 33554432", "uciok"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + err := eng.Run(uci.CmdUCI{}) + if err != nil { + t.Fatal(err) + } + + id := eng.ID() + if id["name"] != "TestEngine" { + t.Errorf("expected name TestEngine, got %s", id["name"]) + } + if id["author"] != "test" { + t.Errorf("expected author test, got %s", id["author"]) + } + + opts := eng.Options() + if _, ok := opts["Hash"]; !ok { + t.Error("expected Hash option") + } +} + +func Test_FakeAdapter_CmdGo(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "go": {"info depth 10 score cp 50 nodes 1000 nps 500000 tbhits 0 time 2 pv e2e4", "bestmove e2e4"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + pos := chess.StartingPosition() + cmdPos := uci.CmdPosition{Position: pos} + cmdGo := uci.CmdGo{MoveTime: 100} + if err := eng.Run(cmdPos, cmdGo); err != nil { + t.Fatal(err) + } + + results := eng.SearchResults() + if results.BestMove == (chess.Move{}) { + t.Fatal("expected best move") + } + if results.Info.Depth != 10 { + t.Errorf("expected depth 10, got %d", results.Info.Depth) + } + if results.Info.Score.CP != 50 { + t.Errorf("expected score cp 50, got %d", results.Info.Score.CP) + } +} + +func Test_FakeAdapter_CmdEval(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "eval": {"Final evaluation 12.5"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + pos := chess.StartingPosition() + cmdPos := uci.CmdPosition{Position: pos} + if err := eng.Run(cmdPos, uci.CmdEval{}); err != nil { + t.Fatal(err) + } + + eval := eng.Eval() + if eval != 1250 { + t.Errorf("expected eval 1250, got %d", eval) + } +} + +func Test_FakeAdapter_MultiPV(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "go": { + "info depth 10 multipv 1 score cp 50 nodes 1000 pv e2e4", + "info depth 10 multipv 2 score cp 30 nodes 1000 pv d2d4", + "bestmove e2e4", + }, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + pos := chess.StartingPosition() + cmdPos := uci.CmdPosition{Position: pos} + cmdGo := uci.CmdGo{MoveTime: 100} + if err := eng.Run(cmdPos, cmdGo); err != nil { + t.Fatal(err) + } + + results := eng.SearchResults() + if len(results.MultiPVInfo) != 2 { + t.Fatalf("expected 2 MultiPV lines, got %d", len(results.MultiPVInfo)) + } + if results.MultiPVInfo[0].Score.CP != 50 { + t.Errorf("expected cp 50 for pv 1, got %d", results.MultiPVInfo[0].Score.CP) + } + if results.MultiPVInfo[1].Score.CP != 30 { + t.Errorf("expected cp 30 for pv 2, got %d", results.MultiPVInfo[1].Score.CP) + } +} + +func Test_EngineSearchResultsReturnsDefensiveCopy(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "go": { + "info depth 10 multipv 1 score cp 50 nodes 1000 pv e2e4 e7e5", + "info depth 10 multipv 2 score cp 30 nodes 1000 pv d2d4 d7d5", + "bestmove e2e4", + }, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + pos := chess.StartingPosition() + if err := eng.Run(uci.CmdPosition{Position: pos}, uci.CmdGo{MoveTime: 100}); err != nil { + t.Fatal(err) + } + + results := eng.SearchResults() + results.Info.PV[0] = chess.Move{} + results.MultiPVInfo[0] = uci.Info{} + results.MultiPVInfo[1].PV[0] = chess.Move{} + + fresh := eng.SearchResults() + if fresh.Info.PV[0] == (chess.Move{}) { + t.Fatal("SearchResults returned mutable Info.PV backing array") + } + if fresh.MultiPVInfo[0].Score.CP != 50 { + t.Fatalf("SearchResults returned mutable MultiPVInfo backing array, cp = %d", fresh.MultiPVInfo[0].Score.CP) + } + if fresh.MultiPVInfo[1].PV[0] == (chess.Move{}) { + t.Fatal("SearchResults returned mutable MultiPVInfo PV backing array") + } +} + +func Test_FakeAdapter_CmdIsReady(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "isready": {"readyok"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + if err := eng.Run(uci.CmdIsReady{}); err != nil { + t.Fatal(err) + } +} + +func Test_FakeAdapter_FireAndForgetPassthrough(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{}, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + if err := eng.Run(uci.CmdUCINewGame{}); err != nil { + t.Fatal(err) + } + if err := eng.Run(uci.CmdStop{}); err != nil { + t.Fatal(err) + } + if err := eng.Run(uci.CmdPonderHit{}); err != nil { + t.Fatal(err) + } +} + +func Test_FakeAdapter_CmdPositionStoredOnEngine(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "position": {"readyok"}, + "go": {"bestmove e7e5"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + fenStr := "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1" + pos := &chess.Position{} + if err := pos.UnmarshalText([]byte(fenStr)); err != nil { + t.Fatal(err) + } + cmdPos := uci.CmdPosition{Position: pos} + cmdGo := uci.CmdGo{MoveTime: 100} + if err := eng.Run(cmdPos, cmdGo); err != nil { + t.Fatal(err) + } + + bestMove := eng.SearchResults().BestMove + if bestMove == (chess.Move{}) { + t.Fatal("expected best move decoded against non-starting position") + } + if bestMove.S1().String() != "e7" || bestMove.S2().String() != "e5" { + t.Errorf("expected e7e5, got %s%s", bestMove.S1(), bestMove.S2()) + } +} + +func Test_EngineIDReturnsDefensiveCopy(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "uci": {"id name TestEngine", "uciok"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + if err := eng.Run(uci.CmdUCI{}); err != nil { + t.Fatal(err) + } + + id := eng.ID() + id["name"] = "Mutated" + id["injected"] = "value" + + id2 := eng.ID() + if id2["name"] != "TestEngine" { + t.Errorf("ID() returned shared map; external mutation leaked back, got name=%q", id2["name"]) + } + if _, ok := id2["injected"]; ok { + t.Errorf("ID() returned shared map; injected key persisted across calls") + } +} + +func Test_EngineOptionsReturnsDefensiveCopy(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "uci": {"option name Hash type spin default 16 min 1 max 1024", "uciok"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + if err := eng.Run(uci.CmdUCI{}); err != nil { + t.Fatal(err) + } + + opts := eng.Options() + opts["Hash"] = uci.Option{Name: "Hash", Type: uci.OptionSpin, Default: "9999"} + opts["Injected"] = uci.Option{Name: "Injected"} + + opts2 := eng.Options() + if opts2["Hash"].Default != "16" { + t.Errorf("Options() returned shared map; external mutation leaked back, got Hash.Default=%q", opts2["Hash"].Default) + } + if _, ok := opts2["Injected"]; ok { + t.Errorf("Options() returned shared map; injected key persisted across calls") + } +} + +func Test_FakeAdapter_FireAndForgetNoResponseShortCircuit(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{}, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + if err := eng.Run(uci.CmdUCINewGame{}); err != nil { + t.Fatalf("CmdUCINewGame should short-circuit on empty response: %v", err) + } + if err := eng.Run(uci.CmdStop{}); err != nil { + t.Fatalf("CmdStop should short-circuit on empty response: %v", err) + } + if err := eng.Run(uci.CmdPonderHit{}); err != nil { + t.Fatalf("CmdPonderHit should short-circuit on empty response: %v", err) + } +} + +func Test_FakeAdapter_CmdSetOptionRendersCorrectly(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "setoption": {}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + cmd := uci.CmdSetOption{Name: "UCI_Elo", Value: "1500"} + got := cmd.String() + want := "setoption name UCI_Elo value 1500" + if got != want { + t.Errorf("CmdSetOption.String() = %q, want %q", got, want) + } + if err := eng.Run(cmd); err != nil { + t.Fatal(err) + } +} + +func Test_InfoUnmarshalTextWDL(t *testing.T) { + info := &uci.Info{} + line := "info depth 24 seldepth 32 multipv 1 score cp 29 wdl 791 209 0 nodes 5130101 nps 819897 hashfull 967 tbhits 0 time 6257 pv d2d4" + if err := info.UnmarshalText([]byte(line)); err != nil { + t.Fatal(err) + } + if info.Score.Win != 791 || info.Score.Draw != 209 || info.Score.Loss != 0 { + t.Errorf("wdl parse: got Win=%d Draw=%d Loss=%d, want 791/209/0", info.Score.Win, info.Score.Draw, info.Score.Loss) + } + if info.Score.CP != 29 { + t.Errorf("cp parse: got %d, want 29", info.Score.CP) + } + if info.Depth != 24 || info.Nodes != 5130101 || info.Hashfull != 967 { + t.Errorf("field parse: got depth=%d nodes=%d hashfull=%d, want 24/5130101/967", info.Depth, info.Nodes, info.Hashfull) + } +} + +func Test_FakeAdapter_FullGame(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "uci": {"id name FakeFish", "uciok"}, + "isready": {"readyok"}, + "go": {"info depth 1 score cp 10 nodes 1 pv e2e4", "bestmove e2e4"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + if err := eng.Run(uci.CmdUCI{}, uci.CmdIsReady{}, uci.CmdUCINewGame{}); err != nil { + t.Fatal(err) + } + + id := eng.ID() + if id["name"] != "FakeFish" { + t.Errorf("expected name FakeFish, got %s", id["name"]) + } + + pos := chess.StartingPosition() + cmdPos := uci.CmdPosition{Position: pos} + cmdGo := uci.CmdGo{MoveTime: 100} + if err := eng.Run(cmdPos, cmdGo); err != nil { + t.Fatal(err) + } + + bestMove := eng.SearchResults().BestMove + if bestMove == (chess.Move{}) { + t.Fatal("expected best move") + } + san, err := chess.SAN().Encode(pos, bestMove) + if err != nil { + t.Fatalf("SAN encode failed: %v", err) + } + if san != "e4" { + t.Errorf("expected e4, got %s", san) + } +} + +func Test_CmdEval_MalformedReturnsError(t *testing.T) { + pos := chess.StartingPosition() + + t.Run("non-numeric value", func(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "eval": {"Final evaluation notanumber"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + err := eng.Run(uci.CmdPosition{Position: pos}, uci.CmdEval{}) + if err == nil { + t.Fatal("expected error for malformed eval value, got nil") + } + if !strings.Contains(err.Error(), "notanumber") { + t.Errorf("expected error to mention the bad value, got %v", err) + } + }) + + t.Run("missing value", func(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "eval": {"Final evaluation"}, + }, + } + eng := uci.NewWithAdapter(fake) + defer eng.Close() + + err := eng.Run(uci.CmdPosition{Position: pos}, uci.CmdEval{}) + if err == nil { + t.Fatal("expected error for eval line with no value, got nil") + } + }) +} + +func Test_CmdUCI_MalformedOptionLoggedUnderDebug(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "uci": { + "id name TestEngine", + "option name Hash type spin default 16 min 1 max 1024", + "option name Bad type notatype default 1", + "uciok", + }, + }, + } + + t.Run("logged and non-fatal when debug on", func(t *testing.T) { + var buf bytes.Buffer + eng := uci.NewWithAdapter(fake, uci.Logger(log.New(&buf, "", 0)), uci.Debug) + defer eng.Close() + + if err := eng.Run(uci.CmdUCI{}); err != nil { + t.Fatalf("malformed option should not be fatal, got %v", err) + } + + opts := eng.Options() + if _, ok := opts["Hash"]; !ok { + t.Error("expected the valid Hash option to still be parsed") + } + if _, ok := opts["Bad"]; ok { + t.Error("malformed option should not appear in Options()") + } + + if !strings.Contains(buf.String(), "dropping malformed option line") { + t.Errorf("expected malformed option to be logged, got %q", buf.String()) + } + }) + + t.Run("silent when debug off", func(t *testing.T) { + var buf bytes.Buffer + eng := uci.NewWithAdapter(fake, uci.Logger(log.New(&buf, "", 0))) + defer eng.Close() + + if err := eng.Run(uci.CmdUCI{}); err != nil { + t.Fatalf("malformed option should not be fatal, got %v", err) + } + if buf.String() != "" { + t.Errorf("expected no logging without debug, got %q", buf.String()) + } + }) +} + +func Test_CmdGo_MalformedInfoLineLoggedUnderDebug(t *testing.T) { + fake := &uci.FakeAdapter{ + Responses: map[string][]string{ + "go": { + "info depth abc", + "info depth 10 score cp 50 nodes 1000 pv e2e4", + "bestmove e2e4", + }, + }, + } + + t.Run("logged and non-fatal when debug on", func(t *testing.T) { + var buf bytes.Buffer + eng := uci.NewWithAdapter(fake, uci.Logger(log.New(&buf, "", 0)), uci.Debug) + defer eng.Close() + + pos := chess.StartingPosition() + if err := eng.Run(uci.CmdPosition{Position: pos}, uci.CmdGo{MoveTime: 100}); err != nil { + t.Fatalf("malformed info line should not be fatal, got %v", err) + } + + results := eng.SearchResults() + if results.BestMove == (chess.Move{}) { + t.Fatal("expected best move to still be parsed") + } + if results.Info.Depth != 10 { + t.Errorf("expected valid info depth 10 to survive, got %d", results.Info.Depth) + } + + if !strings.Contains(buf.String(), "dropping unparseable info line") { + t.Errorf("expected malformed info line to be logged, got %q", buf.String()) + } + }) + + t.Run("silent when debug off", func(t *testing.T) { + var buf bytes.Buffer + eng := uci.NewWithAdapter(fake, uci.Logger(log.New(&buf, "", 0))) + defer eng.Close() + + pos := chess.StartingPosition() + if err := eng.Run(uci.CmdPosition{Position: pos}, uci.CmdGo{MoveTime: 100}); err != nil { + t.Fatalf("malformed info line should not be fatal, got %v", err) + } + if buf.String() != "" { + t.Errorf("expected no logging without debug, got %q", buf.String()) + } + }) +} diff --git a/uci/chess960_test.go b/uci/chess960_test.go new file mode 100644 index 00000000..ea47cb91 --- /dev/null +++ b/uci/chess960_test.go @@ -0,0 +1,254 @@ +package uci_test + +import ( + "strings" + "sync" + "testing" + "time" + + "github.com/corentings/chess/v3" + "github.com/corentings/chess/v3/uci" +) + +// recordingAdapter is a test Adapter that both returns canned responses (keyed +// by the command's first word, like FakeAdapter) and records the exact command +// strings sent to the engine, so tests can assert on protocol ordering. +type recordingAdapter struct { + mu sync.Mutex + sent []string + responses map[string][]string +} + +func newRecordingAdapter(responses map[string][]string) *recordingAdapter { + return &recordingAdapter{responses: responses} +} + +func (r *recordingAdapter) Exchange(cmd uci.Cmd) ([]string, error) { + r.mu.Lock() + r.sent = append(r.sent, cmd.String()) + r.mu.Unlock() + if cmd.IsDone("") { + return nil, nil + } + key := strings.SplitN(cmd.String(), " ", 2)[0] + var lines []string + for _, line := range r.responses[key] { + lines = append(lines, line) + if cmd.IsDone(line) { + break + } + } + return lines, nil +} + +func (r *recordingAdapter) Close() error { return nil } + +func (r *recordingAdapter) commands() []string { + r.mu.Lock() + defer r.mu.Unlock() + out := make([]string, len(r.sent)) + copy(out, r.sent) + return out +} + +// chess960CastlePosition returns a Chess960-variant position where White's +// king-side castle is legal: king e1, rook h1, an empty path, and the black +// king far from rank 1. The Shredder-FEN rights field ("H") infers the variant. +func chess960CastlePosition(t *testing.T) *chess.Position { + t.Helper() + fenOpt, err := chess.FEN("4k3/8/8/8/8/8/8/4K2R w H - 0 1") + if err != nil { + t.Fatalf("FEN: %v", err) + } + game := chess.NewGame(fenOpt) + if game.Position().Variant() != chess.Chess960 { + t.Fatalf("position variant = %v, want Chess960", game.Position().Variant()) + } + return game.Position() +} + +func containsCommand(sent []string, want string) bool { + for _, s := range sent { + if s == want { + return true + } + } + return false +} + +func firstIndexOfPrefix(sent []string, prefix string) int { + for i, s := range sent { + if strings.HasPrefix(s, prefix) { + return i + } + } + return -1 +} + +// TestEngineNegotiatesUCIChess960 asserts that sending a Chess960 position +// makes the engine enable the UCI_Chess960 option before the position command, +// but only because the engine advertises the option. +func TestEngineNegotiatesUCIChess960(t *testing.T) { + fake := newRecordingAdapter(map[string][]string{ + "uci": { + "id name test-engine", + "option name UCI_Chess960 type check default false", + "uciok", + }, + }) + eng := uci.NewWithAdapter(fake) + if err := eng.Run(uci.CmdUCI{}); err != nil { + t.Fatalf("CmdUCI: %v", err) + } + if err := eng.Run(uci.CmdPosition{Position: chess960CastlePosition(t)}); err != nil { + t.Fatalf("CmdPosition: %v", err) + } + + sent := fake.commands() + if !containsCommand(sent, "setoption name UCI_Chess960 value true") { + t.Fatalf("expected UCI_Chess960=true to be sent, got %v", sent) + } + setIdx := firstIndexOfPrefix(sent, "setoption name UCI_Chess960 value true") + posIdx := firstIndexOfPrefix(sent, "position fen ") + if setIdx < 0 || posIdx < 0 || setIdx > posIdx { + t.Errorf("setoption must precede position: %v", sent) + } +} + +// TestEngineDoesNotNegotiateWithoutOption asserts that when the engine does not +// advertise UCI_Chess960, no setoption is sent (the codec still encodes +// king-to-rook, but the option is left untouched). +func TestEngineDoesNotNegotiateWithoutOption(t *testing.T) { + fake := newRecordingAdapter(map[string][]string{ + "uci": {"id name no-chess960-engine", "uciok"}, + }) + eng := uci.NewWithAdapter(fake) + if err := eng.Run(uci.CmdUCI{}); err != nil { + t.Fatalf("CmdUCI: %v", err) + } + if err := eng.Run(uci.CmdPosition{Position: chess960CastlePosition(t)}); err != nil { + t.Fatalf("CmdPosition: %v", err) + } + for _, s := range fake.commands() { + if strings.HasPrefix(s, "setoption") { + t.Errorf("unexpected setoption sent to engine without the option: %q", s) + } + } +} + +// TestEngineTogglesUCIChess960OffForStandard asserts the option is disabled +// again when a later standard position is sent, so a mixed session keeps the +// engine's castling interpretation in sync. +func TestEngineTogglesUCIChess960OffForStandard(t *testing.T) { + fake := newRecordingAdapter(map[string][]string{ + "uci": { + "option name UCI_Chess960 type check default false", + "uciok", + }, + }) + eng := uci.NewWithAdapter(fake) + if err := eng.Run(uci.CmdUCI{}); err != nil { + t.Fatalf("CmdUCI: %v", err) + } + if err := eng.Run(uci.CmdPosition{Position: chess960CastlePosition(t)}); err != nil { + t.Fatalf("Chess960 CmdPosition: %v", err) + } + if err := eng.Run(uci.CmdPosition{Position: chess.StartingPosition()}); err != nil { + t.Fatalf("standard CmdPosition: %v", err) + } + sent := fake.commands() + if !containsCommand(sent, "setoption name UCI_Chess960 value true") { + t.Errorf("expected UCI_Chess960=true sent for Chess960 position: %v", sent) + } + if !containsCommand(sent, "setoption name UCI_Chess960 value false") { + t.Errorf("expected UCI_Chess960=false sent for standard position: %v", sent) + } +} + +// TestEngineDecodesBestMoveKingToRook asserts that a best move reported in the +// Chess960 king-to-rook form ("e1h1") decodes to the canonical castle whose +// king destination is g1. +func TestEngineDecodesBestMoveKingToRook(t *testing.T) { + fake := newRecordingAdapter(map[string][]string{ + "position": nil, + "go": {"bestmove e1h1"}, + }) + eng := uci.NewWithAdapter(fake) + pos := chess960CastlePosition(t) + if err := eng.Run(uci.CmdPosition{Position: pos}); err != nil { + t.Fatalf("CmdPosition: %v", err) + } + if err := eng.Run(uci.CmdGo{MoveTime: 10 * time.Millisecond}); err != nil { + t.Fatalf("CmdGo: %v", err) + } + best := eng.SearchResults().BestMove + if best.S1() != chess.E1 || best.S2() != chess.G1 { + t.Fatalf("bestmove = %v-%v, want e1-g1 (canonical castle)", best.S1(), best.S2()) + } + if !best.HasTag(chess.KingSideCastle) { + t.Errorf("bestmove %v: missing KingSideCastle tag", best) + } +} + +// TestCmdPositionEncodesChess960CastleKingToRook asserts the position command +// string emits king-to-rook for a Chess960 castle supplied in the move list, +// replaying through the position so the rook origin is correct. +func TestCmdPositionEncodesChess960CastleKingToRook(t *testing.T) { + pos := chess960CastlePosition(t) + // The king-side castle from this position: king e1 -> g1, rook h1 -> f1. + var castle chess.Move + for _, m := range pos.ValidMoves() { + if m.HasTag(chess.KingSideCastle) { + castle = m + break + } + } + if castle.S1() != chess.E1 { // sanity: a castle exists + t.Fatalf("no king-side castle found in position") + } + got := uci.CmdPosition{Position: pos, Moves: []chess.Move{castle}}.String() + if !strings.Contains(got, "moves e1h1") { + t.Errorf("CmdPosition = %q, want moves to contain king-to-rook \"e1h1\"", got) + } +} + +// TestCmdPositionReplaysChess960MovesBeforeCastle verifies Chess960 move-list +// serialization advances through prior plies before encoding a later castle. +func TestCmdPositionReplaysChess960MovesBeforeCastle(t *testing.T) { + fenOpt, err := chess.FEN("1n2k3/8/8/8/8/8/8/1N2K2R w H - 0 1") + if err != nil { + t.Fatalf("FEN: %v", err) + } + initial := chess.NewGame(fenOpt).Position() + + whiteKnight, err := chess.UCI().Decode(initial, "b1c3") + if err != nil { + t.Fatalf("decode white knight move: %v", err) + } + afterWhite := initial.Update(whiteKnight) + blackKnight, err := chess.UCI().Decode(afterWhite, "b8c6") + if err != nil { + t.Fatalf("decode black knight move: %v", err) + } + beforeCastle := afterWhite.Update(blackKnight) + + var castle chess.Move + for _, m := range beforeCastle.ValidMoves() { + if m.HasTag(chess.KingSideCastle) { + castle = m + break + } + } + if castle.S1() != chess.E1 { + t.Fatal("no king-side castle found after the preceding moves") + } + + got := uci.CmdPosition{ + Position: initial, + Moves: []chess.Move{whiteKnight, blackKnight, castle}, + }.String() + const wantMoves = "moves b1c3 b8c6 e1h1" + if !strings.HasSuffix(got, wantMoves) { + t.Errorf("CmdPosition = %q, want suffix %q", got, wantMoves) + } +} diff --git a/uci/cmd.go b/uci/cmd.go index 5d28bd1f..20ba2450 100644 --- a/uci/cmd.go +++ b/uci/cmd.go @@ -1,7 +1,6 @@ package uci import ( - "bufio" "errors" "fmt" "math" @@ -9,155 +8,154 @@ import ( "strings" "time" - "github.com/corentings/chess/v2" + "github.com/corentings/chess/v3" ) -// Cmd is a UCI compliant command. +// Cmd represents a command sent to a UCI engine. Each implementation defines +// how the command is serialized (String), when the engine's response is +// complete (IsDone), how to process the response (Handle), and whether the +// command requires exclusive access to the engine (LockRequired). type Cmd interface { fmt.Stringer - ProcessResponse(e *Engine) error + IsDone(line string) bool + Handle(lines []string, e *Engine) error + LockRequired() bool } -type cmdNoOptions struct { - F func(e *Engine) error - Name string -} +// CmdUCI sends the "uci" command and waits for the "uciok" response. The engine +// reports its identity and available options. +type CmdUCI struct{} -func (cmd cmdNoOptions) String() string { - return cmd.Name -} +func (CmdUCI) String() string { return "uci" } -func (cmd cmdNoOptions) ProcessResponse(e *Engine) error { - return cmd.F(e) -} +func (CmdUCI) IsDone(line string) bool { return line == "uciok" } -var ( - // CmdUCI corresponds to the "uci" command: - // tell engine to use the uci (universal chess interface), - // this will be send once as a first command after program boot - // to tell the engine to switch to uci mode. - // After receiving the uci command the engine must identify itself with the "id" command - // and sent the "option" commands to tell the GUI which engine settings the engine supports if any. - // After that the engine should sent "uciok" to acknowledge the uci mode. - // If no uciok is sent within a certain time period, the engine task will be killed by the GUI. - //nolint:gochecknoglobals // Will need to improve this - // TODO: Remove global variable - CmdUCI = cmdNoOptions{Name: "uci", F: func(e *Engine) error { - e.id = map[string]string{} - e.options = map[string]Option{} - scanner := bufio.NewScanner(e.out) - for scanner.Scan() { - text := e.readLine(scanner) - k, v, err := parseIDLine(text) - if err == nil { - e.id[k] = v - continue - } - o := &Option{} - err = o.UnmarshalText([]byte(text)) - if err == nil { - e.options[o.Name] = *o - continue - } - if text == "uciok" { - break - } +func (CmdUCI) LockRequired() bool { return true } + +func (CmdUCI) Handle(lines []string, e *Engine) error { + e.id = map[string]string{} + e.options = map[string]Option{} + for _, text := range lines { + k, v, err := parseIDLine(text) + if err == nil { + e.id[k] = v + continue } - return nil - }} - - // CmdIsReady corresponds to the "isready" command: - // this is used to synchronize the engine with the GUI. When the GUI has sent a command or - // multiple commands that can take some time to complete, - // this command can be used to wait for the engine to be ready again or - // to ping the engine to find out if it is still alive. - // E.g. this should be sent after setting the path to the tablebases as this can take some time. - // This command is also required once before the engine is asked to do any search - // to wait for the engine to finish initializing. - // This command must always be answered with "readyok" and can be sent also when the engine is calculating - // in which case the engine should also immediately answer with "readyok" without stopping the search. - CmdIsReady = cmdNoOptions{Name: "isready", F: func(e *Engine) error { - scanner := bufio.NewScanner(e.out) - for scanner.Scan() { - text := e.readLine(scanner) - if text == "readyok" { - break + o := &Option{} + errOpt := o.UnmarshalText([]byte(text)) + if errOpt == nil { + e.options[o.Name] = *o + continue + } + if e.debug { + switch { + case strings.HasPrefix(text, "id "): + e.logger.Printf("uci: dropping malformed id line %q: %v", text, err) + case strings.HasPrefix(text, "option "): + e.logger.Printf("uci: dropping malformed option line %q: %v", text, errOpt) } } - return nil - }} - - // CmdUCINewGame corresponds to the "ucinewgame" command: - // this is sent to the engine when the next search (started with "position" and "go") will be from - // a different game. This can be a new game the engine should play or a new game it should analyse but - // also the next position from a testsuite with positions only. - // If the GUI hasn't sent a "ucinewgame" before the first "position" command, the engine shouldn't - // expect any further ucinewgame commands as the GUI is probably not supporting the ucinewgame command. - // So the engine should not rely on this command even though all new GUIs should support it. - // As the engine's reaction to "ucinewgame" can take some time the GUI should always send "isready" - // after "ucinewgame" to wait for the engine to finish its operation. - CmdUCINewGame = cmdNoOptions{Name: "ucinewgame", F: func(_ *Engine) error { - return nil - }} - - // CmdPonderHit corresponds to the "ponderhit" command: - // the user has played the expected move. This will be sent if the engine was told to ponder on the same move - // the user has played. The engine should continue searching but switch from pondering to normal search. - CmdPonderHit = cmdNoOptions{Name: "ponderhit", F: func(_ *Engine) error { - return nil - }} - - // CmdStop corresponds to the "stop" command: - // stop calculating as soon as possible, - // don't forget the "bestmove" and possibly the "ponder" token when finishing the search. - CmdStop = cmdNoOptions{Name: "stop", F: func(_ *Engine) error { - return nil - }} - - // CmdQuit (shouldn't be used directly as its handled by Engine.Close()) corresponds to the "quit" command: - // quit the program as soon as possible. - CmdQuit = cmdNoOptions{Name: "quit", F: func(_ *Engine) error { - return nil - }} - - // CmdEval is a non-standard command that requests the engine's static evaluation of the current position. - CmdEval = cmdNoOptions{Name: "eval", F: func(e *Engine) error { - scanner := bufio.NewScanner(e.out) - for scanner.Scan() { - text := e.readLine(scanner) - if strings.Contains(text, "error") { - return errors.New("eval command not supported") + } + return nil +} + +// CmdIsReady sends the "isready" command and waits for the "readyok" response, +// confirming the engine is ready to accept further commands. +type CmdIsReady struct{} + +func (CmdIsReady) String() string { return "isready" } + +func (CmdIsReady) IsDone(line string) bool { return line == "readyok" } + +func (CmdIsReady) LockRequired() bool { return true } + +func (CmdIsReady) Handle(_ []string, _ *Engine) error { return nil } + +// CmdUCINewGame sends the "ucinewgame" command, signaling the engine to clear +// any state from previous games (e.g. hash tables). +type CmdUCINewGame struct{} + +func (CmdUCINewGame) String() string { return "ucinewgame" } + +func (CmdUCINewGame) IsDone(_ string) bool { return true } + +func (CmdUCINewGame) LockRequired() bool { return true } + +func (CmdUCINewGame) Handle(_ []string, _ *Engine) error { return nil } + +// CmdPonderHit sends the "ponderhit" command, informing the engine that the +// opponent has played the move it was pondering. +type CmdPonderHit struct{} + +func (CmdPonderHit) String() string { return "ponderhit" } + +func (CmdPonderHit) IsDone(_ string) bool { return true } + +func (CmdPonderHit) LockRequired() bool { return false } + +func (CmdPonderHit) Handle(_ []string, _ *Engine) error { return nil } + +// CmdStop sends the "stop" command, instructing the engine to stop calculating +// and return the best move found so far. +type CmdStop struct{} + +func (CmdStop) String() string { return "stop" } + +func (CmdStop) IsDone(_ string) bool { return true } + +func (CmdStop) LockRequired() bool { return false } + +func (CmdStop) Handle(_ []string, _ *Engine) error { return nil } + +// CmdQuit sends the "quit" command, instructing the engine to exit. +type CmdQuit struct{} + +func (CmdQuit) String() string { return "quit" } + +func (CmdQuit) IsDone(_ string) bool { return true } + +func (CmdQuit) LockRequired() bool { return true } + +func (CmdQuit) Handle(_ []string, _ *Engine) error { return nil } + +// CmdEval sends the "eval" command and parses the engine's static evaluation +// output. Not all engines support this command. +type CmdEval struct{} + +func (CmdEval) String() string { return "eval" } + +func (CmdEval) IsDone(line string) bool { + lower := strings.ToLower(line) + return strings.HasPrefix(line, "Final evaluation") || + strings.Contains(lower, "error") || + strings.Contains(lower, "unknown command") +} + +func (CmdEval) LockRequired() bool { return true } + +func (CmdEval) Handle(lines []string, e *Engine) error { + for _, text := range lines { + lower := strings.ToLower(text) + if strings.Contains(lower, "error") || strings.Contains(lower, "unknown command") { + return errors.New("uci: eval command not supported") + } + if strings.HasPrefix(text, "Final evaluation") { + parts := strings.Fields(text) + if len(parts) < 3 { + return fmt.Errorf("uci: malformed eval line %q", text) } - if strings.HasPrefix(text, "Final evaluation") { - parts := strings.Fields(text) - if len(parts) >= 3 { - evalStr := parts[2] - eval, err := strconv.ParseFloat(evalStr, 64) - if err == nil { - e.eval = int(math.Round(eval * 100)) - } - break - } + eval, err := strconv.ParseFloat(parts[2], 64) + if err != nil { + return fmt.Errorf("uci: invalid eval value %q: %w", parts[2], err) } + e.eval = int(math.Round(eval * 100)) + break } - return nil - }} -) + } + return nil +} -// CmdSetOption corresponds to the "setoption" command: -// this is sent to the engine when the user wants to change the internal parameters -// of the engine. For the "button" type no value is needed. -// One string will be sent for each parameter and this will only be sent when the engine is waiting. -// The name of the option in should not be case sensitive and can inludes spaces like also the value. -// The substrings "value" and "name" should be avoided in and to allow unambiguous parsing, -// for example do not use = "draw value". -// Here are some strings for the example below: -// -// "setoption name Nullmove value true\n" -// "setoption name Selectivity value 3\n" -// "setoption name Style value Risky\n" -// "setoption name Clear Hash\n" -// "setoption name NalimovPath value c:\chess\tb\4;c:\chess\tb\5\n" +// CmdSetOption sends a "setoption" command to change an engine option at runtime. type CmdSetOption struct { Name string Value string @@ -167,20 +165,17 @@ func (cmd CmdSetOption) String() string { return fmt.Sprintf("setoption name %s value %s", cmd.Name, cmd.Value) } -// ProcessResponse implements the Cmd interface. -func (cmd CmdSetOption) ProcessResponse(_ *Engine) error { - return nil -} +func (CmdSetOption) IsDone(_ string) bool { return true } + +func (CmdSetOption) LockRequired() bool { return false } + +func (CmdSetOption) Handle(_ []string, _ *Engine) error { return nil } -// CmdPosition corresponds to the "position" command: -// set up the position described in fenstring on the internal board and -// play the moves on the internal chess board. -// if the game was played from the start position the string "startpos" will be sent -// Note: no "new" command is needed. However, if this position is from a different game than -// the last position sent to the engine, the GUI should have sent a "ucinewgame" inbetween. +// CmdPosition sends a "position" command to set the engine's current position, +// optionally applying a sequence of moves from the starting position or a FEN. type CmdPosition struct { Position *chess.Position - Moves []*chess.Move + Moves []chess.Move } func (cmd CmdPosition) String() string { @@ -190,61 +185,44 @@ func (cmd CmdPosition) String() string { if len(cmd.Moves) == 0 { return "position fen " + cmd.Position.String() } - moveStrs := []string{} + moveStrs := make([]string, 0, len(cmd.Moves)) + // Chess960 castling is encoded king-to-rook ("e1h1"), whose rook origin is + // only known from the board at the moment the move is played. Replay the + // move list through position copies so each move encodes against its true + // pre-move position. Standard chess skips the replay: its castling is a + // fixed king-to-destination form that needs no board lookup. + cur := cmd.Position + chess960 := cur.Variant() == chess.Chess960 for _, m := range cmd.Moves { - mStr := chess.UCINotation{}.Encode(nil, m) + mStr := mustEncodeUCI(cur, m) moveStrs = append(moveStrs, mStr) + if chess960 { + cur = cur.Update(m) + } } return fmt.Sprintf("position fen %s moves %s", cmd.Position, strings.Join(moveStrs, " ")) } -// ProcessResponse implements the Cmd interface. -func (CmdPosition) ProcessResponse(_ *Engine) error { - return nil +// mustEncodeUCI encodes m with the fixed UCI codec. UCI() always returns a +// valid codec, so an error indicates a programming invariant violation. +func mustEncodeUCI(pos *chess.Position, m chess.Move) string { + text, err := chess.UCI().Encode(pos, m) + if err != nil { + panic(fmt.Errorf("uci: encode move: %w", err)) + } + return text } -// CmdGo corresponds to the "go" command: -// start calculating on the current position set up with the "position" command. -// There are a number of commands that can follow this command, all will be sent in the same string. -// If one command is not send its value should be interpreted as it would not influence the search. -// - searchmoves .... -// restrict search to this moves only -// Example: After "position startpos" and "go infinite searchmoves e2e4 d2d4" -// the engine should only search the two moves e2e4 and d2d4 in the initial position. -// - ponder -// start searching in pondering mode. -// Do not exit the search in ponder mode, even if it's mate! -// This means that the last move sent in in the position string is the ponder move. -// The engine can do what it wants to do, but after a "ponderhit" command -// it should execute the suggested move to ponder on. This means that the ponder move sent by -// the GUI can be interpreted as a recommendation about which move to ponder. However, if the -// engine decides to ponder on a different move, it should not display any mainlines as they are -// likely to be misinterpreted by the GUI because the GUI expects the engine to ponder -// on the suggested move. -// - wtime -// white has x msec left on the clock -// - btime -// black has x msec left on the clock -// - winc -// white increment per move in mseconds if x > 0 -// - binc -// black increment per move in mseconds if x > 0 -// - movestogo -// there are x moves to the next time control, -// this will only be sent if x > 0, -// if you don't get this and get the wtime and btime it's sudden death -// - depth -// search x plies only. -// - nodes -// search x nodes only, -// - mate -// search for a mate in x moves -// - movetime -// search exactly x mseconds -// - infinite -// search until the "stop" command. Do not exit the search without being told so in this mode! +func (CmdPosition) IsDone(_ string) bool { return true } + +func (CmdPosition) LockRequired() bool { return true } + +func (CmdPosition) Handle(_ []string, _ *Engine) error { return nil } + +// CmdGo sends a "go" command to start the engine's search. The fields control +// search parameters such as time limits, depth, and node counts. type CmdGo struct { - SearchMoves []*chess.Move + SearchMoves []chess.Move WhiteTime time.Duration BlackTime time.Duration WhiteIncrement time.Duration @@ -296,53 +274,63 @@ func (cmd CmdGo) String() string { if len(cmd.SearchMoves) > 0 { a = append(a, "searchmoves") for _, m := range cmd.SearchMoves { - mStr := chess.UCINotation{}.Encode(nil, m) + mStr, _ := chess.UCI().Encode(nil, m) a = append(a, mStr) } } return strings.Join(a, " ") } -// ProcessResponse implements the Cmd interface. -// TODO: Refactor this function to be shorter and more readable. -// -//nolint:nestif // work to be done -func (CmdGo) ProcessResponse(e *Engine) error { - const maxParts = 4 +func (CmdGo) IsDone(line string) bool { + return strings.HasPrefix(line, "bestmove") +} - scanner := bufio.NewScanner(e.out) +func (CmdGo) LockRequired() bool { return true } + +func parseBestMoveLine(text string, e *Engine) (chess.Move, chess.Move, error) { + const minParts = 2 + const ponderPartIdx = 3 + const minPonderParts = 4 + parts := strings.Split(text, " ") + if len(parts) < minParts { + return chess.Move{}, chess.Move{}, fmt.Errorf("best move not found %s", text) + } + var position *chess.Position + if e.hasPos { + position = e.position.Position + } + bestMove, err := decodeUCIMove(position, parts[1]) + if err != nil { + return chess.Move{}, chess.Move{}, err + } + var ponderMove chess.Move + if len(parts) >= minPonderParts { + ponderMove, err = decodeUCIMove(position, parts[ponderPartIdx]) + if err != nil { + return chess.Move{}, chess.Move{}, err + } + } + return bestMove, ponderMove, nil +} + +func (CmdGo) Handle(lines []string, e *Engine) error { results := SearchResults{MultiPVInfo: make([]Info, 1)} - for scanner.Scan() { - text := e.readLine(scanner) + for _, text := range lines { if strings.HasPrefix(text, "bestmove") { - parts := strings.Split(text, " ") - if len(parts) <= 1 { - return errors.New("best move not found " + text) - } - var position *chess.Position - if e.position != nil { - position = e.position.Position - } else { - position = nil - } - bestMove, err := chess.UCINotation{}.Decode(position, parts[1]) + bestMove, ponderMove, err := parseBestMoveLine(text, e) if err != nil { return err } results.BestMove = bestMove - if len(parts) >= maxParts { - ponderMove, decodeErr := chess.UCINotation{}.Decode(position, parts[3]) - if decodeErr != nil { - return decodeErr - } - results.Ponder = ponderMove - } - break + results.Ponder = ponderMove + continue } info := &Info{} - err := info.UnmarshalText([]byte(text)) - if err != nil { + if err := info.UnmarshalText([]byte(text)); err != nil { + if e.debug && strings.HasPrefix(text, "info ") { + e.logger.Printf("uci: dropping unparseable info line %q: %v", text, err) + } continue } @@ -352,10 +340,8 @@ func (CmdGo) ProcessResponse(e *Engine) error { if info.Multipv > 1 && info.Multipv < 300 { currentPVCount := len(results.MultiPVInfo) - if info.Multipv > currentPVCount { - for i := currentPVCount; i < info.Multipv; i++ { - results.MultiPVInfo = append(results.MultiPVInfo, Info{}) - } + for i := currentPVCount; i < info.Multipv; i++ { + results.MultiPVInfo = append(results.MultiPVInfo, Info{}) } results.MultiPVInfo[info.Multipv-1] = *info } @@ -365,6 +351,17 @@ func (CmdGo) ProcessResponse(e *Engine) error { return nil } +func decodeUCIMove(pos *chess.Position, text string) (chess.Move, error) { + if pos != nil { + return chess.UCI().Decode(pos, text) + } + raw, err := chess.UCI().DecodeRaw(text) + if err != nil { + return chess.Move{}, err + } + return raw.Move(), nil +} + func parseIDLine(s string) (string, string, error) { const numParts = 3 if !strings.HasPrefix(s, "id") { diff --git a/uci/engine.go b/uci/engine.go index f093f9f2..643c4b51 100644 --- a/uci/engine.go +++ b/uci/engine.go @@ -1,149 +1,120 @@ package uci import ( - "bufio" - "fmt" - "io" "log" + "maps" "os" - "os/exec" "sync" + + "github.com/corentings/chess/v3" ) -// Engine represents a UCI compliant chess engine (e.g. Stockfish, Shredder, etc.). -// Engine is safe for concurrent use. +// Engine manages communication with a UCI-compatible chess engine such as +// Stockfish. It sends commands, parses responses, and exposes the engine's +// reported state (ID, options, search results). type Engine struct { - cmd *exec.Cmd - in *io.PipeWriter - out *io.PipeReader - logger *log.Logger - id map[string]string - options map[string]Option - mu *sync.RWMutex - position *CmdPosition - results SearchResults - eval int - debug bool + adapter Adapter + logger *log.Logger + id map[string]string + options map[string]Option + mu *sync.RWMutex + position CmdPosition + hasPos bool + results SearchResults + eval int + debug bool + chess960Enabled bool } -// Debug is an option for the New function to add logging for debugging. This will -// log all output to and from the chess engine. +// Debug enables debug logging of commands sent to and responses received from +// the engine. It is intended to be passed as an option to New. func Debug(e *Engine) { e.debug = true } -// Logger is an option for the New function to customize the logger. The logger is -// only used if the Debug option is also used. +// Logger sets the logger the engine uses for debug output. It is intended to be +// passed as an option to New. func Logger(logger *log.Logger) func(e *Engine) { return func(e *Engine) { e.logger = logger } } -// New constructs an engine from the executable path (found using exec.LookPath). -// New also starts running the executable process in the background. Once created -// the Engine can be controlled via the Run method. +// New creates an Engine backed by a subprocess started from the executable at +// the given path. Optional configuration functions (e.g. Debug, Logger) may be +// passed to customize the engine. func New(path string, opts ...func(e *Engine)) (*Engine, error) { - path, err := exec.LookPath(path) - if err != nil { - return nil, fmt.Errorf("uci: executable not found at path %s %w", path, err) - } - rIn, wIn := io.Pipe() - rOut, wOut := io.Pipe() - cmd := exec.Command(path) - cmd.Stdin = rIn - cmd.Stdout = wOut - e := &Engine{cmd: cmd, in: wIn, out: rOut, mu: &sync.RWMutex{}, logger: log.New(os.Stdout, "uci", log.LstdFlags), position: &CmdPosition{}, results: SearchResults{MultiPVInfo: []Info{}}} - for _, opt := range opts { - opt(e) - } - err = e.cmd.Start() + adapter, err := NewSubprocessAdapter(path) if err != nil { - return nil, fmt.Errorf("uci: failed to start executable %s: %w", path, err) + return nil, err } - go e.cmd.Wait() - - return e, nil + return NewWithAdapter(adapter, opts...), nil } -func (e *Engine) Getpid() int { - return e.cmd.Process.Pid +// NewWithAdapter creates an Engine that communicates through the provided +// Adapter instead of spawning a subprocess. This is primarily useful for +// testing with a FakeAdapter. +func NewWithAdapter(adapter Adapter, opts ...func(e *Engine)) *Engine { + e := &Engine{ + adapter: adapter, + logger: log.New(os.Stdout, "uci", log.LstdFlags), + mu: &sync.RWMutex{}, + position: CmdPosition{}, + results: SearchResults{MultiPVInfo: []Info{}}, + } + for _, opt := range opts { + opt(e) + } + return e } -// ID returns the id values returned from the most recent CmdUCI invocation. It includes -// key value data such as the following: -// id name Stockfish 12 -// id author the Stockfish developers (see AUTHORS file). +// ID returns a copy of the engine's identification key-value pairs as reported +// in response to the CmdUCI command (e.g. name and author). func (e *Engine) ID() map[string]string { e.mu.RLock() defer e.mu.RUnlock() - cp := map[string]string{} - for k, v := range e.id { - cp[k] = v + cp := maps.Clone(e.id) + if cp == nil { + return map[string]string{} } return cp } -// Options returns exposed options from the most recent CmdUCI invocation. It includes -// data such as the following: -// option name Debug Log File type string default -// option name Contempt type spin default 24 min -100 max 100 -// option name Analysis Contempt type combo default Both var Off var White var Black var Both -// option name Threads type spin default 1 min 1 max 512 -// option name Hash type spin default 16 min 1 max 33554432 -// option name Clear Hash type button -// option name Ponder type check default false -// option name MultiPV type spin default 1 min 1 max 500 -// option name Skill Level type spin default 20 min 0 max 20 -// option name Move Overhead type spin default 10 min 0 max 5000 -// option name Slow Mover type spin default 100 min 10 max 1000 -// option name nodestime type spin default 0 min 0 max 10000 -// option name UCI_Chess960 type check default false -// option name UCI_AnalyseMode type check default false -// option name UCI_LimitStrength type check default false -// option name UCI_Elo type spin default 1350 min 1350 max 2850 -// option name UCI_ShowWDL type check default false -// option name SyzygyPath type string default -// option name SyzygyProbeDepth type spin default 1 min 1 max 100 -// option name Syzygy50MoveRule type check default true -// option name SyzygyProbeLimit type spin default 7 min 0 max 7 -// option name Use NNUE type check default true -// option name EvalFile type string default nn-82215d0fd0df.nnue -// The key is the option name and the value is the Option struct. +// Options returns a copy of the engine's available options as reported in +// response to the CmdUCI command. func (e *Engine) Options() map[string]Option { e.mu.RLock() defer e.mu.RUnlock() - cp := map[string]Option{} - for k, v := range e.options { - cp[k] = v + cp := maps.Clone(e.options) + if cp == nil { + return map[string]Option{} } return cp } -// SearchResults returns results from the most recent CmdGo invocation. It includes -// data such as the following: -// info depth 21 seldepth 31 multipv 1 score cp 39 nodes 862438 nps 860716 hashfull 409 tbhits 0 time 1002 pv e2e4 -// bestmove e2e4 ponder c7c5. +// SearchResults returns the results from the most recent CmdGo command. func (e *Engine) SearchResults() SearchResults { e.mu.RLock() defer e.mu.RUnlock() - return e.results + return e.results.copy() } +// Eval returns the static evaluation from the most recent CmdEval command, in +// centipawns. Not all engines support the eval command. func (e *Engine) Eval() int { e.mu.RLock() defer e.mu.RUnlock() return e.eval } -// Run runs the set of Cmds in the order given and returns an error if -// any of the commands fails. Except for CmdStop (usually paired with -// CmdGo's infinite option) all commands block via mutux until completed. +// Run executes the given commands in order, returning the first error +// encountered. Commands that require exclusive access (LockRequired) are +// serialized via the engine's mutex. func (e *Engine) Run(cmds ...Cmd) error { for _, cmd := range cmds { - if cmd.String() == CmdStop.Name { + if !cmd.LockRequired() { if err := e.processCommand(cmd); err != nil { return err } @@ -156,19 +127,24 @@ func (e *Engine) Run(cmds ...Cmd) error { return nil } -// Close releases readers, writers, and processes associated with the -// Engine. It also invokes the CmdQuit to signal the engine to terminate. -func (e *Engine) Close() error { - if err := e.Run(CmdQuit); err != nil { - return err - } - if err := e.in.Close(); err != nil { - return err +// Getpid returns the operating system process ID of the engine subprocess. +// Returns 0 when the engine is not backed by a subprocess (e.g. when created +// with NewWithAdapter using a non-subprocess Adapter). +func (e *Engine) Getpid() int { + if sa, ok := e.adapter.(*SubprocessAdapter); ok { + return sa.Pid() } - if err := e.out.Close(); err != nil { - return err + return 0 +} + +// Close sends a quit command to the engine and closes the underlying adapter. +func (e *Engine) Close() error { + quitErr := e.Run(CmdQuit{}) + closeErr := e.adapter.Close() + if quitErr != nil { + return quitErr } - return e.cmd.Process.Kill() + return closeErr } func (e *Engine) processCommandLocked(cmd Cmd) error { @@ -178,28 +154,54 @@ func (e *Engine) processCommandLocked(cmd Cmd) error { } func (e *Engine) processCommand(cmd Cmd) error { + if posCmd, ok := cmd.(CmdPosition); ok { + if err := e.ensureChess960(posCmd.Position); err != nil { + return err + } + } if e.debug { e.logger.Println(cmd.String()) } - if _, err := fmt.Fprintln(e.in, cmd.String()); err != nil { + lines, err := e.adapter.Exchange(cmd) + if err != nil { return err } - if posCmd, ok := cmd.(*CmdPosition); ok { - e.position = posCmd + if e.debug { + for _, line := range lines { + e.logger.Println(line) + } } if posCmd, ok := cmd.(CmdPosition); ok { - e.position = &posCmd - } - if err := cmd.ProcessResponse(e); err != nil { - return err + e.position = posCmd + e.hasPos = true } - return nil + return cmd.Handle(lines, e) } -func (e *Engine) readLine(scanner *bufio.Scanner) string { - s := scanner.Text() +// ensureChess960 keeps the engine's UCI_Chess960 option aligned with the +// variant of the position about to be sent. A Chess960 position enables the +// option so the engine accepts the king-to-rook castling encoding; a later +// standard position disables it again. The option is toggled only when the +// engine advertises it, and at most once per state change. +func (e *Engine) ensureChess960(pos *chess.Position) error { + want := pos != nil && pos.Variant() == chess.Chess960 + if want == e.chess960Enabled { + return nil + } + if _, ok := e.options["UCI_Chess960"]; !ok { + return nil + } + value := "false" + if want { + value = "true" + } + opt := CmdSetOption{Name: "UCI_Chess960", Value: value} if e.debug { - e.logger.Println(s) + e.logger.Println(opt.String()) + } + if _, err := e.adapter.Exchange(opt); err != nil { + return err } - return s + e.chess960Enabled = want + return nil } diff --git a/uci/engine_test.go b/uci/engine_test.go index 3af7d727..2688469d 100644 --- a/uci/engine_test.go +++ b/uci/engine_test.go @@ -8,8 +8,8 @@ import ( "testing" "time" - "github.com/corentings/chess/v2" - "github.com/corentings/chess/v2/uci" + "github.com/corentings/chess/v3" + "github.com/corentings/chess/v3/uci" ) var engines = []string{"stockfish", "lc0"} @@ -40,7 +40,7 @@ func Test_EngineEval(t *testing.T) { defer eng.Close() cmdPos := uci.CmdPosition{Position: pos} - err = eng.Run(uci.CmdUCI, uci.CmdIsReady, uci.CmdUCINewGame, cmdPos, uci.CmdEval) + err = eng.Run(uci.CmdUCI{}, uci.CmdIsReady{}, uci.CmdUCINewGame{}, cmdPos, uci.CmdEval{}) if name == "stockfish" { if err != nil { @@ -83,12 +83,15 @@ func Test_EngineInfo(t *testing.T) { cmdWDL := uci.CmdSetOption{Name: "UCI_ShowWDL", Value: "true"} cmdPos := uci.CmdPosition{Position: pos} cmdGo := uci.CmdGo{MoveTime: time.Second / 10} - if err := eng.Run(uci.CmdUCI, uci.CmdIsReady, uci.CmdUCINewGame, cmdMultiPV, cmdWDL, cmdPos, cmdGo); err != nil { + if err := eng.Run(uci.CmdUCI{}, uci.CmdIsReady{}, uci.CmdUCINewGame{}, cmdMultiPV, cmdWDL, cmdPos, cmdGo); err != nil { t.Fatal("failed to run command", err) } move := eng.SearchResults().Info.PV[0] - moveStr := chess.AlgebraicNotation{}.Encode(pos, move) + moveStr, err := chess.SAN().Encode(pos, move) + if err != nil { + t.Fatal(err) + } if moveStr != "Ne5" { t.Errorf("expected Ne5, got %s", moveStr) @@ -124,7 +127,7 @@ func Test_EngineMultiPVInfo(t *testing.T) { cmdMultiPV := uci.CmdSetOption{Name: "multipv", Value: "2"} cmdPos := uci.CmdPosition{Position: pos} cmdGo := uci.CmdGo{MoveTime: time.Second / 10} - if err := eng.Run(uci.CmdUCI, uci.CmdIsReady, uci.CmdUCINewGame, cmdMultiPV, cmdPos, cmdGo); err != nil { + if err := eng.Run(uci.CmdUCI{}, uci.CmdIsReady{}, uci.CmdUCINewGame{}, cmdMultiPV, cmdPos, cmdGo); err != nil { t.Fatal("failed to run command", err) } @@ -135,13 +138,19 @@ func Test_EngineMultiPVInfo(t *testing.T) { } move := multiPVInfo[0].PV[0] - moveStr := chess.AlgebraicNotation{}.Encode(pos, move) + moveStr, err := chess.SAN().Encode(pos, move) + if err != nil { + t.Fatal(err) + } if moveStr != "Ne5" { t.Errorf("expected Ne5, got %s", moveStr) } move = multiPVInfo[1].PV[0] - moveStr = chess.AlgebraicNotation{}.Encode(pos, move) + moveStr, err = chess.SAN().Encode(pos, move) + if err != nil { + t.Fatal(err) + } if moveStr != "e5" { t.Errorf("expected e5, got %s", moveStr) } @@ -164,12 +173,11 @@ func Test_UCIMovesTags(t *testing.T) { setOpt := uci.CmdSetOption{Name: "UCI_Elo", Value: "1500"} setPos := uci.CmdPosition{Position: chess.StartingPosition()} setGo := uci.CmdGo{MoveTime: time.Second / 10} - if err := eng.Run(uci.CmdUCI, uci.CmdIsReady, setOpt, uci.CmdUCINewGame, setPos, setGo); err != nil { + if err := eng.Run(uci.CmdUCI{}, uci.CmdIsReady{}, setOpt, uci.CmdUCINewGame{}, setPos, setGo); err != nil { t.Fatal("failed to run command", err) } game := chess.NewGame() - notation := chess.AlgebraicNotation{} for game.Outcome() == chess.NoOutcome { cmdPos := uci.CmdPosition{Position: game.Position()} @@ -180,9 +188,12 @@ func Test_UCIMovesTags(t *testing.T) { move := eng.SearchResults().BestMove pos := game.Position() - san := notation.Encode(pos, move) + san, encodeErr := chess.SAN().Encode(pos, move) + if encodeErr != nil { + t.Fatal(encodeErr) + } - err = game.PushMove(san, nil) + err = game.MoveText(san, chess.SAN(), nil) if err != nil { t.Fatal(fmt.Sprintf("failed to push move %s - %s - %v. Pos: %s", san, move.String(), move.HasTag(chess.Capture), pos.String()), err) } diff --git a/uci/fake.go b/uci/fake.go new file mode 100644 index 00000000..bc826968 --- /dev/null +++ b/uci/fake.go @@ -0,0 +1,35 @@ +package uci + +import "strings" + +// FakeAdapter is a test Adapter that returns canned responses keyed by the +// first word of each command string (e.g. "uci", "go", "isready"). +type FakeAdapter struct { + Responses map[string][]string +} + +// Exchange returns the canned response lines for the given command, or nil if +// no response is configured for the command key. +func (f *FakeAdapter) Exchange(cmd Cmd) ([]string, error) { + key := strings.SplitN(cmd.String(), " ", 2)[0] + responses, ok := f.Responses[key] + if !ok { + return nil, nil + } + if cmd.IsDone("") { + return nil, nil + } + var lines []string + for _, line := range responses { + lines = append(lines, line) + if cmd.IsDone(line) { + break + } + } + return lines, nil +} + +// Close is a no-op for FakeAdapter. +func (f *FakeAdapter) Close() error { + return nil +} diff --git a/uci/info.go b/uci/info.go index 78260daa..8e7e1eca 100644 --- a/uci/info.go +++ b/uci/info.go @@ -2,26 +2,36 @@ package uci import ( "errors" + "fmt" "strconv" "strings" "time" - "github.com/corentings/chess/v2" + "github.com/corentings/chess/v3" ) -var missingWdlErr = errors.New("uci: wdl unavailable; this is mostly likely because UCI_ShowWDL has not been set") +var errMissingWdl = errors.New("uci: wdl unavailable; this is mostly likely because UCI_ShowWDL has not been set") // SearchResults is the result from the most recent CmdGo invocation. It includes // data such as the following: // info depth 21 seldepth 31 multipv 1 score cp 39 nodes 862438 nps 860716 hashfull 409 tbhits 0 time 1002 pv e2e4 // bestmove e2e4 ponder c7c5. type SearchResults struct { - BestMove *chess.Move - Ponder *chess.Move + BestMove chess.Move + Ponder chess.Move MultiPVInfo []Info Info Info } +func (r SearchResults) copy() SearchResults { + return SearchResults{ + BestMove: r.BestMove, + Ponder: r.Ponder, + MultiPVInfo: copyInfoSlice(r.MultiPVInfo), + Info: r.Info.copy(), + } +} + // Info corresponds to the "info" engine output: // the engine wants to send infos to the GUI. This should be done whenever one of the info has changed. // The engine can send only selected infos and multiple infos can be send with one info command, @@ -89,8 +99,8 @@ type SearchResults struct { // If is greater than 1, always send all k lines in k strings together. // The engine should only send this if the option "UCI_ShowCurrLine" is set to true. type Info struct { - CurrentMove *chess.Move - PV []*chess.Move + CurrentMove chess.Move + PV []chess.Move Score Score Depth int Seldepth int @@ -104,6 +114,77 @@ type Info struct { CPULoad int } +func (info *Info) copy() Info { + out := *info + out.PV = append([]chess.Move{}, info.PV...) + return out +} + +func copyInfoSlice(src []Info) []Info { + if src == nil { + return []Info{} + } + out := make([]Info, len(src)) + for idx, info := range src { + out[idx] = info.copy() + } + return out +} + +func parseInfoInt(field, value string) (int, error) { + v, err := strconv.Atoi(value) + if err != nil { + return 0, fmt.Errorf("uci: invalid info %s %q: %w", field, value, err) + } + return v, nil +} + +// assignIntField parses value as an integer and assigns it to the Info field +// identified by field. It returns true when the field was recognised. +func (info *Info) assignIntField(field, value string) (bool, error) { + v, err := parseInfoInt(field, value) + if err != nil { + return false, err + } + switch field { + case "depth": + info.Depth = v + case "seldepth": + info.Seldepth = v + case "multipv": + info.Multipv = v + case "cp": + info.Score.CP = v + case "nodes": + info.Nodes = v + case "currmovenumber": + info.CurrentMoveNumber = v + case "hashfull": + info.Hashfull = v + case "tbhits": + info.TBHits = v + case "nps": + info.NPS = v + case "cpuload": + info.CPULoad = v + default: + return false, nil + } + return true, nil +} + +func nextInfoToken(s string) (string, string, bool) { + s = strings.TrimLeft(s, " ") + if s == "" { + return "", "", false + } + token, rest, found := strings.Cut(s, " ") + if !found { + return s, "", true + } + return token, rest, true +} + // Score corresponds to the "info"'s score engine output: // - score // - cp @@ -138,7 +219,7 @@ type Score struct { func (score Score) WinPct() (float32, error) { total := score.Win + score.Draw + score.Loss if total == 0 { - return 0.0, missingWdlErr + return 0.0, errMissingWdl } return float32(score.Win) / float32(total), nil } @@ -150,7 +231,7 @@ func (score Score) WinPct() (float32, error) { func (score Score) DrawPct() (float32, error) { total := score.Win + score.Draw + score.Loss if total == 0 { - return 0.0, missingWdlErr + return 0.0, errMissingWdl } return float32(score.Draw) / float32(total), nil } @@ -162,28 +243,32 @@ func (score Score) DrawPct() (float32, error) { func (score Score) LossPct() (float32, error) { total := score.Win + score.Draw + score.Loss if total == 0 { - return 0.0, missingWdlErr + return 0.0, errMissingWdl } return float32(score.Loss) / float32(total), nil } // UnmarshalText implements the encoding.TextUnmarshaler interface and parses. // data like the following: -// info depth 24 seldepth 32 multipv 1 score cp 29 wdl 791 209 0 nodes 5130101 nps 819897 hashfull 967 tbhits 0 time 6257 pv d2d4 -// TODO: Refactor this function to be shorter. -// -//nolint:funlen // This function is long because it has to parse a lot of different fields. +// info depth 24 seldepth 32 multipv 1 score cp 29 wdl 791 209 0 nodes 5130101 nps 819897 hashfull 967 tbhits 0 time 6257 pv d2d4. func (info *Info) UnmarshalText(text []byte) error { - parts := strings.Split(string(text), " ") - if len(parts) == 0 { - return errors.New("uci: invalid info line " + string(text)) - } - if parts[0] != "info" { - return errors.New("uci: invalid info line " + string(text)) + line := string(text) + token, rest, ok := nextInfoToken(line) + if !ok || token != "info" { + return fmt.Errorf("uci: invalid info line %s", line) } ref := "" - for i := 1; i < len(parts); i++ { - s := parts[i] + var ( + s string + nextRest string + ) + for { + s, nextRest, ok = nextInfoToken(rest) + if !ok { + break + } + rest = nextRest + switch s { case "score": continue @@ -199,105 +284,58 @@ func (info *Info) UnmarshalText(text []byte) error { continue } switch ref { - case "depth": - v, err := strconv.Atoi(s) - if err != nil { - return err - } - info.Depth = v - case "seldepth": - v, err := strconv.Atoi(s) - if err != nil { - return err - } - info.Seldepth = v - case "multipv": - v, err := strconv.Atoi(s) - if err != nil { - return err + case "wdl": + draw, drawRest, wdlOK := nextInfoToken(rest) + if !wdlOK { + return fmt.Errorf("uci: truncated wdl score: %s", line) } - info.Multipv = v - case "cp": - v, err := strconv.Atoi(s) - if err != nil { - return err + loss, afterLoss, wdlOK := nextInfoToken(drawRest) + if !wdlOK { + return fmt.Errorf("uci: truncated wdl score: %s", line) } - info.Score.CP = v - case "wdl": + rest = afterLoss + var err error - info.Score.Win, err = strconv.Atoi(parts[i]) + info.Score.Win, err = parseInfoInt("wdl win", s) if err != nil { return err } - info.Score.Draw, err = strconv.Atoi(parts[i+1]) + info.Score.Draw, err = parseInfoInt("wdl draw", draw) if err != nil { return err } - info.Score.Loss, err = strconv.Atoi(parts[i+2]) + info.Score.Loss, err = parseInfoInt("wdl loss", loss) if err != nil { return err } - i += 2 - case "nodes": - v, err := strconv.Atoi(s) - if err != nil { - return err - } - info.Nodes = v case "mate": - v, err := strconv.Atoi(s) + v, err := parseInfoInt("mate", s) if err != nil { return err } info.Score.Mate = v - case "currmovenumber": - v, err := strconv.Atoi(s) - if err != nil { - return err - } - info.CurrentMoveNumber = v - case "currmove": - m, err := chess.UCINotation{}.Decode(nil, s) - if err != nil { - return err - } - info.CurrentMove = m - case "hashfull": - v, err := strconv.Atoi(s) - if err != nil { - return err - } - info.Hashfull = v - case "tbhits": - v, err := strconv.Atoi(s) - if err != nil { - return err - } - info.TBHits = v case "time": - v, err := strconv.Atoi(s) + v, err := parseInfoInt("time", s) if err != nil { return err } info.Time = time.Millisecond * time.Duration(v) - case "nps": - v, err := strconv.Atoi(s) - if err != nil { - return err - } - info.NPS = v - case "cpuload": - v, err := strconv.Atoi(s) + case "currmove": + raw, err := chess.UCI().DecodeRaw(s) if err != nil { - return err + return fmt.Errorf("uci: invalid info currmove %q: %w", s, err) } - info.CPULoad = v + info.CurrentMove = raw.Move() case "pv": - m, err := chess.UCINotation{}.Decode(nil, s) + raw, err := chess.UCI().DecodeRaw(s) if err != nil { + return fmt.Errorf("uci: invalid info pv move %q: %w", s, err) + } + info.PV = append(info.PV, raw.Move()) + default: + if _, err := info.assignIntField(ref, s); err != nil { return err } - info.PV = append(info.PV, m) } if ref != "pv" { ref = "" diff --git a/uci/option.go b/uci/option.go index fbbd20f0..32098c5a 100644 --- a/uci/option.go +++ b/uci/option.go @@ -2,6 +2,7 @@ package uci import ( "errors" + "fmt" "strings" ) @@ -197,5 +198,5 @@ func optionTypeFromString(s string) (OptionType, error) { return ot, nil } } - return OptionNoType, errors.New("uci: invalid option type " + s) + return OptionNoType, fmt.Errorf("uci: invalid option type %s", s) } diff --git a/utils.go b/utils.go index 0b726832..f8b82b39 100644 --- a/utils.go +++ b/utils.go @@ -13,7 +13,7 @@ func isWhitespace(ch byte) bool { } func isResult(s string) bool { - return s == "1-0" || s == "0-1" || s == "1/2-1/2" || s == "*" + return s == WhiteWon.String() || s == BlackWon.String() || s == Draw.String() || s == "*" } // Helper function to check if a character is a valid file. diff --git a/zobrist.go b/zobrist.go index a77d94d5..aea8cc52 100644 --- a/zobrist.go +++ b/zobrist.go @@ -1,272 +1,10 @@ package chess -import ( - "encoding/hex" - "errors" - "strconv" - "strings" -) - -// ZobristHasher provides methods to generate Zobrist hashes for chess positions -type ZobristHasher struct { - enPassantRank int - enPassantFile int - pawnNearby bool - hasError bool -} - -// Hash represents a Zobrist hash as a byte slice -type Hash []byte - -// emptyHash is the initial hash value -var emptyHash = parseHexString("0000000000000000") - -// NewChessHasher creates a new instance of ChessHasher -// Deprecated: Use NewZobristHasher instead -func NewChessHasher() *ZobristHasher { - return &ZobristHasher{ - enPassantRank: -1, - enPassantFile: -1, - pawnNearby: false, - hasError: false, - } -} - -// NewZobristHasher creates a new instance of ZobristHasher -func NewZobristHasher() *ZobristHasher { - return &ZobristHasher{ - enPassantRank: -1, - enPassantFile: -1, - pawnNearby: false, - hasError: false, - } -} - -// parseHexString converts a hex string to a byte slice efficiently -func parseHexString(s string) Hash { - // Ensure the input has an even length - if len(s)%2 != 0 { - return nil // Handle invalid input - } - - // Use a preallocated buffer for zero allocations - result := make([]byte, len(s)/2) - _, err := hex.Decode(result, []byte(s)) +// HashFromFEN computes the Zobrist hash of a chess position from its FEN string. +func HashFromFEN(fen string) (uint64, error) { + pos, err := decodeFENForHash(fen) if err != nil { - return nil // Handle invalid hex string - } - - return result -} - -// createHexString converts a byte slice to a hex string efficiently -func createHexString(h Hash) string { - return hex.EncodeToString(h) -} - -func xorArrays(a, b Hash) { - length := len(a) - if len(b) < length { - length = len(b) + return 0, err } - for i := 0; i < length; i++ { - a[i] ^= b[i] // XOR in place, avoiding new slice allocation - } -} - -// xorHash performs an in-place XOR operation on a hash -func (ch *ZobristHasher) xorHash(arr Hash, num int) { - // Get the precomputed Polyglot hash as a byte slice - polyglotHash := GetPolyglotHashBytes(num) - - // Perform in-place XOR - xorArrays(arr, polyglotHash) -} - -// parseEnPassant processes the en passant square -func (ch *ZobristHasher) parseEnPassant(s string) { - if s == "-" { - return - } - - if len(s) != 2 { - ch.hasError = true - return - } - - file := int(s[0] - 'a') - rank := int(s[1] - '1') - - if file < 0 || file > 7 || rank < 0 || rank > 7 { - ch.hasError = true - return - } - - ch.enPassantFile = file - ch.enPassantRank = rank -} - -// hashSide computes the hash for the side to move -func (ch *ZobristHasher) hashSide(arr Hash, color Color) Hash { - if color == White { - ch.xorHash(arr, 780) - } - return arr -} - -// hashCastling updates hash based on castling rights -func (ch *ZobristHasher) hashCastling(arr Hash, s string) Hash { - if s == "-" { - return arr - } - - if strings.Contains(s, "K") { - ch.xorHash(arr, 768) - } - if strings.Contains(s, "Q") { - ch.xorHash(arr, 769) - } - if strings.Contains(s, "k") { - ch.xorHash(arr, 770) - } - if strings.Contains(s, "q") { - ch.xorHash(arr, 771) - } - - return arr -} - -// hashPieces computes hash for the piece positions -func (ch *ZobristHasher) hashPieces(arr Hash, s string) Hash { - ranks := strings.Split(s, "/") - if len(ranks) != 8 { - ch.hasError = true - return arr - } - - for i := 0; i < 8; i++ { - file := 0 - rank := 7 - i - for j := 0; j < len(ranks[i]); j++ { - piece := ranks[i][j] - switch piece { - case 'p': - ch.xorHash(arr, 8*rank+file) - if ch.enPassantRank == 2 && rank == 3 && ch.enPassantFile > 0 && file == ch.enPassantFile-1 { - ch.pawnNearby = true - } - if ch.enPassantRank == 2 && rank == 3 && ch.enPassantFile < 7 && file == ch.enPassantFile+1 { - ch.pawnNearby = true - } - file++ - case 'P': - ch.xorHash(arr, 64*1+8*rank+file) - if ch.enPassantRank == 5 && rank == 4 && ch.enPassantFile > 0 && file == ch.enPassantFile-1 { - ch.pawnNearby = true - } - if ch.enPassantRank == 5 && rank == 4 && ch.enPassantFile < 7 && file == ch.enPassantFile+1 { - ch.pawnNearby = true - } - file++ - case 'n': - ch.xorHash(arr, 64*2+8*rank+file) - file++ - case 'N': - ch.xorHash(arr, 64*3+8*rank+file) - file++ - case 'b': - ch.xorHash(arr, 64*4+8*rank+file) - file++ - case 'B': - ch.xorHash(arr, 64*5+8*rank+file) - file++ - case 'r': - ch.xorHash(arr, 64*6+8*rank+file) - file++ - case 'R': - ch.xorHash(arr, 64*7+8*rank+file) - file++ - case 'q': - ch.xorHash(arr, 64*8+8*rank+file) - file++ - case 'Q': - ch.xorHash(arr, 64*9+8*rank+file) - file++ - case 'k': - ch.xorHash(arr, 64*10+8*rank+file) - file++ - case 'K': - ch.xorHash(arr, 64*11+8*rank+file) - file++ - case '1', '2', '3', '4', '5', '6', '7', '8': - file += int(piece - '0') - default: - ch.hasError = true - return arr - } - } - if file != 8 { - ch.hasError = true - } - } - return arr -} - -// HashPosition computes a Zobrist hash for a chess position in FEN notation -func (ch *ZobristHasher) HashPosition(fen string) (string, error) { - ch.hasError = false - ch.enPassantRank = -1 - ch.enPassantFile = -1 - ch.pawnNearby = false - - // FEN should have at least 4 parts - parts := strings.SplitN(fen, " ", 5) - if len(parts) < 4 { - return "", errors.New("invalid FEN format") - } - - pieces, color, castling, enPassant := parts[0], parts[1], parts[2], parts[3] - - // Quick validation without regex - if len(color) != 1 || (color[0] != 'w' && color[0] != 'b') { - return "", errors.New("invalid side to move") - } - - if len(castling) > 4 { - return "", errors.New("invalid castling rights") - } - - hash := make(Hash, len(emptyHash)) - copy(hash, emptyHash) - - ch.parseEnPassant(enPassant) - hash = ch.hashPieces(hash, pieces) - - if ch.pawnNearby { - ch.xorHash(hash, 772+ch.enPassantFile) - } - - hash = ch.hashSide(hash, ColorFromString(color)) - hash = ch.hashCastling(hash, castling) - - if ch.hasError { - return "", errors.New("invalid piece placement") - } - - return createHexString(hash), nil -} - -func ZobristHashToUint64(hash string) uint64 { - // Ensure the input is exactly 16 hex digits - if len(hash) != 16 { - return 0 - } - - // Convert directly using `strconv.ParseUint` - result, err := strconv.ParseUint(hash, 16, 64) - if err != nil { - return 0 - } - - return result + return pos.ZobristHash(), nil } diff --git a/zobrist_test.go b/zobrist_test.go index 38f0aaa5..6939a36e 100644 --- a/zobrist_test.go +++ b/zobrist_test.go @@ -1,271 +1,148 @@ -package chess +package chess_test import ( - "strings" "testing" -) - -func TestChessHasher(t *testing.T) { - t.Run("Basic Position Validation", func(t *testing.T) { - hasher := NewZobristHasher() - t.Run("should correctly hash the starting position", func(t *testing.T) { - startPos := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" - hash, err := hasher.HashPosition(startPos) - if err != nil { - t.Errorf("Expected no error, got %v", err) - } - if len(hash) != 16 { - t.Errorf("Expected hash length of 16, got %d", len(hash)) - } - if hash != "463b96181691fc9c" { - t.Errorf("Expected hash 463b96181691fc9c, got %s", hash) - } - }) - - t.Run("should handle empty board position", func(t *testing.T) { - emptyPos := "8/8/8/8/8/8/8/8 w - - 0 1" - hash, err := hasher.HashPosition(emptyPos) - if err != nil { - t.Errorf("Expected no error, got %v", err) - } - if hash != "f8d626aaaf278509" { - t.Errorf("Expected hash f8d626aaaf278509, got %s", hash) - } - }) - }) + "github.com/corentings/chess/v3" +) +func TestHashFromFEN(t *testing.T) { t.Run("Known Position Hashes", func(t *testing.T) { - hasher := NewZobristHasher() knownPositions := []struct { + name string fen string - hash string + hash uint64 }{ - { - "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", - "463b96181691fc9c", - }, - { - "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1", - "823c9b50fd114196", - }, - { - "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2", - "0844931a6ef4b9a0", - }, - { - "rnbqkbnr/ppp1pppp/8/3p4/4P3/8/PPPP1PPP/RNBQKBNR w KQkq d6 0 2", - "0756b94461c50fb0", - }, - { - "8/8/8/8/8/8/8/8 w - - 0 1", - "f8d626aaaf278509", - }, + {"startpos", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", 0x463b96181691fc9c}, + {"after_e4", "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1", 0x823c9b50fd114196}, + {"after_e4_e5", "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2", 0x0844931a6ef4b9a0}, + {"empty", "8/8/8/8/8/8/8/8 w - - 0 1", 0xf8d626aaaf278509}, } - for _, tc := range knownPositions { - t.Run(tc.fen, func(t *testing.T) { - hash, err := hasher.HashPosition(tc.fen) + t.Run(tc.name, func(t *testing.T) { + hash, err := chess.HashFromFEN(tc.fen) if err != nil { - t.Errorf("Expected no error, got %v", err) + t.Fatalf("Expected no error, got %v", err) } - if !strings.EqualFold(hash, tc.hash) { - t.Errorf("Expected hash %s, got %s", tc.hash, hash) + if hash != tc.hash { + t.Errorf("Expected hash %016x, got %016x", tc.hash, hash) } }) } }) t.Run("Error Handling", func(t *testing.T) { - hasher := NewZobristHasher() - - t.Run("should return error for invalid FEN format", func(t *testing.T) { - invalidFen := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR" - _, err := hasher.HashPosition(invalidFen) - if err == nil { - t.Error("Expected error for invalid FEN format") - } - }) - - t.Run("should detect invalid piece placement", func(t *testing.T) { - invalidPieces := "rnbqkbnr/ppppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" - _, err := hasher.HashPosition(invalidPieces) - if err == nil { - t.Error("Expected error for invalid piece placement") - } - }) - - t.Run("should detect invalid ranks count", func(t *testing.T) { - invalidRanks := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP w KQkq - 0 1" - _, err := hasher.HashPosition(invalidRanks) - if err == nil { - t.Error("Expected error for invalid ranks count") - } - }) + invalidFENs := []struct { + name string + fen string + }{ + {"bad_piece_count", "rnbqkbnr/ppppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"}, + {"bad_ranks_count", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP w KQkq - 0 1"}, + {"bad_side_to_move", "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR x KQkq - 0 1"}, + {"bad_piece_char", "rnbqkbnZ/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"}, + {"empty_string", ""}, + } + for _, tc := range invalidFENs { + t.Run(tc.name, func(t *testing.T) { + if _, err := chess.HashFromFEN(tc.fen); err == nil { + t.Errorf("Expected error for %q, got nil", tc.fen) + } + }) + } }) t.Run("Color Handling", func(t *testing.T) { - hasher := NewZobristHasher() - - t.Run("should produce different hashes for white and black to move", func(t *testing.T) { - positionWhite := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" - positionBlack := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR b KQkq - 0 1" + positionWhite := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" + positionBlack := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR b KQkq - 0 1" - hashWhite, err1 := hasher.HashPosition(positionWhite) - hashBlack, err2 := hasher.HashPosition(positionBlack) + hashWhite, err1 := chess.HashFromFEN(positionWhite) + hashBlack, err2 := chess.HashFromFEN(positionBlack) - if err1 != nil || err2 != nil { - t.Errorf("Unexpected errors: %v, %v", err1, err2) - } - if hashWhite == hashBlack { - t.Error("Expected different hashes for white and black to move") - } - if len(hashWhite) != 16 || len(hashBlack) != 16 { - t.Error("Expected hash length of 16") - } - }) + if err1 != nil || err2 != nil { + t.Fatalf("Unexpected errors: %v, %v", err1, err2) + } + if hashWhite == hashBlack { + t.Error("Expected different hashes for white and black to move") + } }) t.Run("Castling Rights", func(t *testing.T) { - hasher := NewZobristHasher() - - t.Run("should produce different hashes for different castling rights", func(t *testing.T) { - withAllCastling := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" - withoutCastling := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w - - 0 1" - onlyWhiteCastling := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1" + withAllCastling := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" + withoutCastling := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w - - 0 1" + onlyWhiteCastling := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1" - hashAll, _ := hasher.HashPosition(withAllCastling) - hashNone, _ := hasher.HashPosition(withoutCastling) - hashWhite, _ := hasher.HashPosition(onlyWhiteCastling) + hashAll, _ := chess.HashFromFEN(withAllCastling) + hashNone, _ := chess.HashFromFEN(withoutCastling) + hashWhite, _ := chess.HashFromFEN(onlyWhiteCastling) - if hashAll == hashNone || hashAll == hashWhite || hashWhite == hashNone { - t.Error("Expected different hashes for different castling rights") - } - }) + if hashAll == hashNone || hashAll == hashWhite || hashWhite == hashNone { + t.Error("Expected different hashes for different castling rights") + } }) t.Run("En Passant", func(t *testing.T) { - hasher := NewZobristHasher() - - t.Run("should handle en passant squares correctly", func(t *testing.T) { - afterE4E5 := "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2" - afterE4E6 := "rnbqkbnr/pppp1ppp/4p3/8/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2" - - hashWithEP, err1 := hasher.HashPosition(afterE4E5) - hashWithoutEP, err2 := hasher.HashPosition(afterE4E6) + afterE4E5 := "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2" + afterE4E6 := "rnbqkbnr/pppp1ppp/4p3/8/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2" - if err1 != nil || err2 != nil { - t.Errorf("Unexpected errors: %v, %v", err1, err2) - } - if hashWithEP == hashWithoutEP { - t.Error("Expected different hashes for positions with and without en passant") - } - if hashWithEP != "0844931a6ef4b9a0" { - t.Errorf("Expected hash 0844931a6ef4b9a0, got %s", hashWithEP) - } - if hashWithoutEP != "f44b6961e533d1c4" { - t.Errorf("Expected hash f44b6961e533d1c4, got %s", hashWithoutEP) - } - }) - - t.Run("should validate en passant square format", func(t *testing.T) { - invalidEP := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq e99 0 1" - _, err := hasher.HashPosition(invalidEP) - if err == nil { - t.Error("Expected error for invalid en passant square") - } - }) - }) - - t.Run("Position Equality", func(t *testing.T) { - hasher := NewZobristHasher() - - t.Run("should produce identical hashes for identical positions", func(t *testing.T) { - position := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" - hash1, _ := hasher.HashPosition(position) - hash2, _ := hasher.HashPosition(position) + hashWithEP, err1 := chess.HashFromFEN(afterE4E5) + hashWithoutEP, err2 := chess.HashFromFEN(afterE4E6) - if hash1 != hash2 { - t.Error("Expected identical hashes for identical positions") - } - }) - - t.Run("should produce different hashes for different positions", func(t *testing.T) { - position1 := "rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq e3 0 1" - position2 := "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2" - - hash1, _ := hasher.HashPosition(position1) - hash2, _ := hasher.HashPosition(position2) - - if hash1 == hash2 { - t.Error("Expected different hashes for different positions") - } - }) + if err1 != nil || err2 != nil { + t.Fatalf("Unexpected errors: %v, %v", err1, err2) + } + if hashWithEP == hashWithoutEP { + t.Error("Expected different hashes for positions with and without en passant") + } + if hashWithEP != 0x0844931a6ef4b9a0 { + t.Errorf("Expected hash 0844931a6ef4b9a0, got %016x", hashWithEP) + } + if hashWithoutEP != 0xf44b6961e533d1c4 { + t.Errorf("Expected hash f44b6961e533d1c4, got %016x", hashWithoutEP) + } }) t.Run("Piece Placement", func(t *testing.T) { - hasher := NewZobristHasher() - - t.Run("should handle individual piece placement correctly", func(t *testing.T) { - positions := []string{ - "4k3/8/8/8/8/8/8/4K3 w - - 0 1", // Kings only - "4k3/8/8/8/8/8/8/R3K3 w - - 0 1", // White rook added - "4k3/8/8/8/8/8/8/B3K3 w - - 0 1", // White bishop instead - "4k3/8/8/8/8/8/8/N3K3 w - - 0 1", // White knight instead - "4k3/8/8/8/8/8/8/Q3K3 w - - 0 1", // White queen instead - } + positions := []string{ + "4k3/8/8/8/8/8/8/4K3 w - - 0 1", + "4k3/8/8/8/8/8/8/R3K3 w - - 0 1", + "4k3/8/8/8/8/8/8/B3K3 w - - 0 1", + "4k3/8/8/8/8/8/8/N3K3 w - - 0 1", + "4k3/8/8/8/8/8/8/Q3K3 w - - 0 1", + "4k3/8/8/8/8/8/8/3K2rr w - - 0 1", + } - hashes := make([]string, len(positions)) - for i, pos := range positions { - hash, err := hasher.HashPosition(pos) - if err != nil { - t.Errorf("Unexpected error for position %s: %v", pos, err) - } - hashes[i] = hash + hashes := make([]uint64, len(positions)) + for i, pos := range positions { + hash, err := chess.HashFromFEN(pos) + if err != nil { + t.Fatalf("Unexpected error for position %s: %v", pos, err) } + hashes[i] = hash + } - // Check that all hashes are different - for i := 0; i < len(hashes); i++ { - for j := i + 1; j < len(hashes); j++ { - if hashes[i] == hashes[j] { - t.Errorf("Expected different hashes for positions %s and %s", - positions[i], positions[j]) - } + for i := range hashes { + for j := i + 1; j < len(hashes); j++ { + if hashes[i] == hashes[j] { + t.Errorf("Expected different hashes for positions %s and %s", + positions[i], positions[j]) } } - }) - }) -} - -func TestZobristHashToUint64(t *testing.T) { - t.Run("valid 16-digit hexadecimal hash is converted correctly", func(t *testing.T) { - hash := "463b96181691fc9c" - expected := uint64(0x463b96181691fc9c) - result := ZobristHashToUint64(hash) - - if result != expected { - t.Fatalf("expected value %v but got %v", expected, result) } }) - - t.Run("invalid hash format returns error", func(t *testing.T) { - hash := "invalidhash" - _ = ZobristHashToUint64(hash) - }) - - t.Run("empty hash returns error", func(t *testing.T) { - hash := "" - _ = ZobristHashToUint64(hash) - }) } -func BenchmarkHashPosition(b *testing.B) { - hasher := NewZobristHasher() - fen := "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1" - - b.ReportAllocs() - - for i := 0; i < b.N; i++ { - _, _ = hasher.HashPosition(fen) +func BenchmarkHashFromFEN(b *testing.B) { + fens := []string{ + "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1", + "8/8/8/8/8/8/8/8 w - - 0 1", + "rnbqkbnr/pppp1ppp/8/4p3/4P3/8/PPPP1PPP/RNBQKBNR w KQkq e6 0 2", + } + for _, fen := range fens { + b.Run(fen, func(b *testing.B) { + b.ReportAllocs() + for range b.N { + _, _ = chess.HashFromFEN(fen) + } + }) } }