Per-user language selection

.gitignore

@@ -15,6 +15,7 @@ node_modules/
 # local scratch / generated artifacts
 /graphify-out/
 PLAN_*.md
+_*
 test-results/
 .claude/
 .opencode/

CONFIGURATION.md

@@ -59,7 +59,8 @@ environment:
 | `SECRET_KEY`                 | —            | **yes**¹ | Cookie signing key                             |
 | `DATABASE_ARGS`              | `{}`         |    no    | Extra args for the psycopg3 driver             |
 | `SESSION_LIFETIME`           | `1`          |    no    | Session duration in days                       |
-| `LANGUAGE_FILE`              | `i18n/en.json` |    no    | UI translation file                            |
+| `LANGUAGES`                  | `["en","de","fr","es","pl"]` |    no    | Locale codes offered in the picker (ships all five; narrow via this list) |
+| `DEFAULT_LANGUAGE`           | `en`         |    no    | Fallback language (NULL user pref + no cookie). Must be listed in `LANGUAGES` |
 | `THEME_FILE`                 | `theme.css`  |    no    | Colour theme stylesheet (`static/`-relative name, or absolute path/URL) |
 | `BASE_PATH`                  | *(empty)*    |    no    | URL prefix WARP is mounted under, e.g. `/warp` (see [Mounting under a URL prefix](#mounting-under-a-url-prefix)) |
 | `WEEKS_IN_ADVANCE`           | `1`          |    no    | Weeks after current week available for booking |
@@ -163,22 +164,36 @@ python -c 'from subprocess import run; print(run(["openssl","rand","16"],capture
 
 ## Language
 
-The UI language is set globally for the instance — all users see the same language.
+The UI language is a **per-user** choice: a language picker on the login
+screen and in **Preferences** lets each user pick their own, stored in
+`user_prefs.language` and carried across login/logout by the `warp_lang`
+cookie. A deployment configures which languages are offered and the fallback:
 
-| Language          | `LANGUAGE_FILE` value |
-| ----------------- | --------------------- |
-| English (default) | `i18n/en.json`        |
-| German            | `i18n/de.json`        |
-| French            | `i18n/fr.json`        |
-| Spanish           | `i18n/es.json`        |
-| Polish            | `i18n/pl.json`        |
+| Setting             | Default      | Meaning |
+| ------------------- | ------------ | ------- |
+| `WARP_LANGUAGES`    | `["en","de","fr","es","pl"]` | JSON array of locale codes offered in the picker (ships all five). Renders only when more than one is listed. |
+| `WARP_DEFAULT_LANGUAGE` | `en`     | Fallback language for users with no pref and no cookie. Must be listed in `WARP_LANGUAGES`. |
 
 ```
-WARP_LANGUAGE_FILE=i18n/de.json
+WARP_LANGUAGES='["en","de","pl"]'
+WARP_DEFAULT_LANGUAGE=en
 ```
 
-The iCal feed and action pages use the same language file for event summaries and
-button labels.
+Resolution precedence: **logged-in** users — `user_prefs.language` → `warp_lang`
+cookie → `DEFAULT_LANGUAGE` (a stale cookie left by another user on a shared
+device does not override your pref). **Login screen** (not logged in) —
+`warp_lang` cookie → `DEFAULT_LANGUAGE`. Preferences lists each offered language
+by name; there is no `Default` entry — a user with no stored preference follows
+`DEFAULT_LANGUAGE` (shown applied, not selectable), so a later `DEFAULT_LANGUAGE`
+change still reaches them. Picking any language pins it.
+
+> **Breaking change:** the former `WARP_LANGUAGE_FILE` (single deployment-wide
+> file) is removed. If still set, it is **silently ignored** (a startup warning
+> on stderr only) and the UI falls back to `DEFAULT_LANGUAGE` (`en`). Migrate by
+> setting `WARP_LANGUAGES` (a JSON array) and `WARP_DEFAULT_LANGUAGE` instead.
+
+The iCal feed and action pages render in the owner's resolved language (a NULL
+pref falls back to `DEFAULT_LANGUAGE`).
 
 ---
 

FEATURES.md

@@ -644,7 +644,7 @@ When a user clicks a link from their calendar, they are taken to a simple WARP p
 2. On confirm: shows **"Seat released"** with the seat name.
 3. On cancel: shows **"Action cancelled"**.
 
-All text on these pages is translated according to the deployment-wide language setting.
+All text on these pages is translated in the owner’s language (a user with no language preference falls back to the deployment default).
 
 ---
 
@@ -668,9 +668,10 @@ All text on these pages is translated according to the deployment-wide language
 ## 20. Multi-Language Support
 
 - WARP supports **English, German, French, Spanish, and Polish**.
-- The language is configured globally per instance via `LANGUAGE_FILE` (e.g., `i18n/de.json`).
+- The language is a **per-user choice**: a flag picker on the login screen and a **Language** row in **Preferences** let each user pick their own. The choice is stored in `user_prefs.language` and carried across login/logout by the `warp_lang` cookie. A user with no stored preference follows the deployment's `DEFAULT_LANGUAGE` (shown applied in Preferences, not selectable); picking any language pins it.
+- Which languages a deployment offers is configured via `WARP_LANGUAGES` (JSON array); the fallback via `WARP_DEFAULT_LANGUAGE`.
 - All UI strings (buttons, labels, error messages, modal text) are translated.
-- The iCal feed uses the same language for event summaries and action page text.
+- The iCal feed and action pages render in the owner's resolved language.
 - Date pickers adapt to the locale (first day of week, month names, etc.).
 
 ---
@@ -830,7 +831,8 @@ A zone admin can **release another user's booking** from the plan map by clickin
 | `MAX_MAP_SIZE`               | 2 MB           | Maximum zone map image size                          |
 | `MAX_CONTENT_LENGTH`         | 5 MB           | Maximum request body size                            |
 | `TIMEZONE`                   | auto-detect    | Timezone label for iCal DTSTART/DTEND                |
-| `LANGUAGE_FILE`              | `i18n/en.json` | UI language file                                     |
+| `LANGUAGES`                  | `["en","de","fr","es","pl"]` | JSON array of locale codes offered in the picker (renders by default) |
+| `DEFAULT_LANGUAGE`           | `en`           | Fallback language (NULL user pref / no cookie)       |
 | `SECRET_KEY`                 | — (required)   | Key for signing session cookies                      |
 | `DATABASE_ADDRESS`          | — (required)   | Database host or `host:port` (port defaults to 5432) |
 | `DATABASE_NAME`             | — (required)   | Database name                                         |

README.md

@@ -181,6 +181,11 @@ for writing new tests.
 
 # Other
 
+## Third-party assets
+
+- **Material Icons** (Google) — `warp/static/material_icons/`, Apache 2.0.
+- **Flag SVGs** — `warp/static/images/flags/`, from [lipis/flag-icons](https://github.com/lipis/flag-icons) (MIT). Used for the per-user language picker.
+
 ## How can I support you
 
 Oh.. I was not expecting that, but you can send a beer via PayPal: https://paypal.me/sebo271

containers/README.md

@@ -165,7 +165,8 @@ LDAP, …) or any other feature, add the relevant `WARP_*` variables under
 | `warp_secret_key` secret  | `mysecretkey`       | A random secret — see [CONFIGURATION.md](../CONFIGURATION.md#secret-key) |
 | `warp_db_password` secret | `postgres_password` | A strong database password (used by both the DB and the app)             |
 | `warp-app` image tag      | `:latest`           | A pinned version, e.g. `:v1.2.3`                                         |
-| `WARP_LANGUAGE_FILE`      | `i18n/en.json`      | Your preferred language (`de`/`fr`/`es`/`pl`)                            |
+| `WARP_LANGUAGES`          | `["en","de","fr","es","pl"]` | JSON array of locale codes offered in the picker (`en`/`de`/`fr`/`es`/`pl`) |
+| `WARP_DEFAULT_LANGUAGE`   | `en`               | Fallback language (must be listed in `WARP_LANGUAGES`)                     |
 
 ---
 
@@ -261,7 +262,8 @@ install the unit files under `~/.config/containers/systemd/` instead.
 4. **Review the unit files** and adjust paths if you changed any of the
    directories above (`Volume=` lines in `warp-db.container` and
    `warp-revproxy.container`), the image reference in `warp-app.container`, and
-   `WARP_LANGUAGE_FILE` (`i18n/en.json`, also `de`/`fr`/`es`/`pl`).
+   `WARP_LANGUAGES` / `WARP_DEFAULT_LANGUAGE` (per-user language picker; see
+   CONFIGURATION.md).
 
 5. **Install the unit files** into the Quadlet drop-in directory and reload:
 

containers/compose/compose.yaml

@@ -40,7 +40,6 @@ services:
       WARP_DATABASE_USER: "postgres"
       WARP_DATABASE_PASSWORD_FILE: /run/secrets/warp_db_password
       WARP_SECRET_KEY_FILE: /run/secrets/warp_secret_key
-      WARP_LANGUAGE_FILE: "i18n/en.json"
       # uWSGI endpoints, mirroring the Quadlet setup: disable the binary uWSGI
       # socket (empty value) so only the HTTP unix socket that Caddy proxies to
       # over the shared /run/warp volume remains. The HTTP socket already defaults

containers/quadlet/warp-app.container

@@ -33,9 +33,6 @@ Environment=WARP_DATABASE_PASSWORD_FILE=/run/secrets/warp-db-password
 Secret=warp-secret-key
 Environment=WARP_SECRET_KEY_FILE=/run/secrets/warp-secret-key
 
-# UI language. Available: en, de, fr, es, pl.
-Environment=WARP_LANGUAGE_FILE=i18n/en.json
-
 # uWSGI endpoints. The in-pod Caddy proxies over the HTTP unix socket on the
 # shared /run/warp volume, so the binary uWSGI socket is disabled (empty value).
 # The HTTP socket already defaults to /run/warp/uwsgi-http.sock in the app, so it

e2e/README.md

@@ -77,6 +77,11 @@ npm run report           # open last HTML report
   test, so no manual cleanup is needed. Mind that jumping forward by a day or
   more expires every login session (`SESSION_LIFETIME`): log in again after
   advancing the clock, or `/xhr/*` calls silently redirect to `/login`.
+- **Language**: the e2e container is started with
+  `WARP_LANGUAGES='["en","de"]'` and `WARP_DEFAULT_LANGUAGE=en`, so the
+  per-user language picker renders with two entries. `setLanguage(page, lang)`
+  (debug only) switches the deployment fallback `DEFAULT_LANGUAGE` at runtime
+  and clears the iCal feed cache; the fixture resets it to `en` between tests.
 - Because all tests share one database, the config pins `workers: 1` and
   `fullyParallel: false`. Do not turn parallelism on without giving each
   worker its own database.

e2e/fixtures.ts

@@ -20,15 +20,16 @@ async function resetServerClock(baseURL: string): Promise<void> {
 }
 
 /**
- * Reset the deployment language to English (see helpers/debug.ts setLanguage).
- * LANGUAGE_FILE is process-global state; a test that switches language would
- * otherwise poison every test after it. Tolerates 404 for a non-debug server.
+ * Reset the deployment fallback language to English (see helpers/debug.ts
+ * setLanguage). DEFAULT_LANGUAGE is process-global state; a test that switches
+ * it would otherwise poison every test after it. Tolerates 404 for a non-debug
+ * server.
  */
 async function resetServerLanguage(baseURL: string): Promise<void> {
   const resp = await fetch(`${baseURL}/debug/set_language`, {
     method: 'POST',
     headers: { 'Content-Type': 'application/json' },
-    body: JSON.stringify({ language_file: 'i18n/en.json' }),
+    body: JSON.stringify({ language: 'en' }),
   });
   if (!resp.ok && resp.status !== 404) {
     throw new Error(`resetting language failed: HTTP ${resp.status}`);

e2e/global-setup.ts

@@ -89,6 +89,10 @@ export default async function globalSetup() {
     // The suite resets the database directly over TCP, so Postgres must bind
     // all interfaces inside the container (off by default — see Dockerfile_debug).
     '-e', 'EXPOSE_POSTGRES=1',
+    // Per-user language picker needs >1 configured language to render the
+    // dropdown; the ical-language spec also switches DEFAULT_LANGUAGE to 'de'.
+    '-e', "WARP_LANGUAGES=[\"en\",\"de\"]",
+    '-e', 'WARP_DEFAULT_LANGUAGE=en',
     IMAGE_TAG,
   ]);
 

e2e/helpers/debug.ts

@@ -33,15 +33,14 @@ export async function advanceDays(page: Page, days: number): Promise<void> {
 }
 
 /**
- * Switch the deployment language (debug only). Sets LANGUAGE_FILE and clears
- * the iCal feed cache so the feed regenerates in the new language.
- * `lang` is a short code ('de','en',...) resolved to `i18n/<lang>.json`,
- * or pass a full path via the second arg. Reset between tests with 'en'.
+ * Switch the deployment fallback language (debug only). Sets DEFAULT_LANGUAGE
+ * (the per-user resolver falls back to it when a user has no pref) and clears
+ * the iCal feed cache so the feed regenerates in the new language. `lang` is a
+ * short code ('de','en',...); reset between tests with 'en'.
  */
-export async function setLanguage(page: Page, lang: string, fullPath?: string): Promise<void> {
-  const languageFile = fullPath ?? `i18n/${lang}.json`;
+export async function setLanguage(page: Page, lang: string): Promise<void> {
   const resp = await page.request.post('/debug/set_language', {
-    data: { language_file: languageFile },
+    data: { language: lang },
     headers: { 'Content-Type': 'application/json' },
   });
   if (!resp.ok()) {

e2e/tests/settings/ical-language.spec.ts

@@ -3,9 +3,10 @@
  *
  * Feed event summaries (phrases: booking / missing / release) and the
  * action-page titles + button labels (Release seat? / Seat released /
- * Confirm / Cancel …) are rendered from the deployment language file
- * (LANGUAGE_FILE). Switched at runtime via the debug-only /debug/set_language
- * endpoint; the per-test fixture resets LANGUAGE_FILE to English afterwards.
+ * Confirm / Cancel ...) are rendered from the resolved language. For a user
+ * with no language pref, that falls back to the deployment DEFAULT_LANGUAGE,
+ * switched at runtime via the debug-only /debug/set_language endpoint; the
+ * per-test fixture resets DEFAULT_LANGUAGE to English afterwards.
  */
 
 import { test, expect } from '../../fixtures';
@@ -37,7 +38,7 @@ async function fetchIcal(page: Page, token: string): Promise<ICalEvent[]> {
   return parseIcal(await resp.text());
 }
 
-// ─── Feed summaries follow LANGUAGE_FILE ────────────────────────────────────
+// ─── Feed summaries follow the resolved language ────────────────────────
 
 test.describe('iCal feed text follows the deployment language', () => {
   test('German: booking summary uses "Platz {name}" and reminders "Platz in … buchen"', async ({ page }) => {
@@ -76,7 +77,7 @@ test.describe('iCal feed text follows the deployment language', () => {
   });
 });
 
-// ─── Action-page text follows LANGUAGE_FILE ─────────────────────────────────
+// ─── Action-page text follows the resolved language ───────────────────────
 
 test.describe('iCal action-page text follows the deployment language', () => {
   test('German: release confirm page shows "Platz freigeben?" and Bestätigen/Abbrechen', async ({ page }) => {