[codex] Isolate kline interval exchange dialects

docs/ARCHITECTURE.md

@@ -107,7 +107,7 @@ Risks and debt:
 - Some legacy compatibility constructors keep old names or parameters while delegating to the new builders. Prefer the direct `build_connector*` functions in new code.
 - `ExchangeFactory` is for latency tests and demos. It now delegates Bybit and OKX creation through the exchange builders, but production code should still prefer exchange-specific builders when credentials, passphrases, or custom behavior matter.
 - `RestClientConfig::max_retries` applies to retryable GET and DELETE failures. POST requests are not automatically retried to avoid repeating order-style side effects.
-- `KlineInterval` includes exchange-specific formatting helpers, so a small amount of exchange dialect knowledge leaks into the shared type layer.
+- `KlineInterval` is a shared semantic interval type; exchange-specific interval formatting belongs in exchange modules.
 - `src/exchanges/okx/` is implemented, but `src/exchanges/okx_perp/` is an empty, unregistered directory. Treat OKX perpetual as not implemented.
 - Some tests depend on public exchange APIs and can fail because of network or upstream API changes.
 - Historical docs previously mixed old plans with current architecture. Current docs now keep those notes in `docs/archive/`.

src/core/types.rs

@@ -370,48 +370,6 @@ pub enum KlineInterval {
     Months1,
 }
 
-impl KlineInterval {
-    pub fn to_binance_format(&self) -> String {
-        match self {
-            Self::Minutes1 => "1m".to_string(),
-            Self::Minutes3 => "3m".to_string(),
-            Self::Minutes5 => "5m".to_string(),
-            Self::Minutes15 => "15m".to_string(),
-            Self::Minutes30 => "30m".to_string(),
-            Self::Hours1 => "1h".to_string(),
-            Self::Hours2 => "2h".to_string(),
-            Self::Hours4 => "4h".to_string(),
-            Self::Hours6 => "6h".to_string(),
-            Self::Hours8 => "8h".to_string(),
-            Self::Hours12 => "12h".to_string(),
-            Self::Days1 => "1d".to_string(),
-            Self::Days3 => "3d".to_string(),
-            Self::Weeks1 => "1w".to_string(),
-            Self::Months1 => "1M".to_string(),
-        }
-    }
-
-    pub fn to_bybit_format(&self) -> String {
-        match self {
-            Self::Minutes1 => "1".to_string(),
-            Self::Minutes3 => "3".to_string(),
-            Self::Minutes5 => "5".to_string(),
-            Self::Minutes15 => "15".to_string(),
-            Self::Minutes30 => "30".to_string(),
-            Self::Hours1 => "60".to_string(),
-            Self::Hours2 => "120".to_string(),
-            Self::Hours4 => "240".to_string(),
-            Self::Hours6 => "360".to_string(),
-            Self::Hours8 => "480".to_string(),
-            Self::Hours12 => "720".to_string(),
-            Self::Days1 => "D".to_string(),
-            Self::Days3 => "3D".to_string(),
-            Self::Weeks1 => "W".to_string(),
-            Self::Months1 => "M".to_string(),
-        }
-    }
-}
-
 impl fmt::Display for KlineInterval {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let description = match self {

src/exchanges/backpack/connector/market_data.rs

@@ -7,7 +7,9 @@ use crate::core::{
         SubscriptionType, Symbol, WebSocketConfig,
     },
 };
-use crate::exchanges::backpack::{codec::BackpackCodec, rest::BackpackRestClient};
+use crate::exchanges::backpack::{
+    codec::BackpackCodec, conversions::kline_interval_to_backpack_string, rest::BackpackRestClient,
+};
 use async_trait::async_trait;
 use rust_decimal::Decimal;
 use tokio::sync::mpsc;
@@ -173,10 +175,10 @@ impl<R: RestClient + Clone, W: WsSession<BackpackCodec>> MarketDataSource for Ma
         start_time: Option<i64>,
         end_time: Option<i64>,
     ) -> Result<Vec<Kline>, ExchangeError> {
-        let interval_str = interval.to_backpack_format();
+        let interval_str = kline_interval_to_backpack_string(interval);
         let klines = self
             .rest
-            .get_klines(&symbol, &interval_str, start_time, end_time, limit)
+            .get_klines(&symbol, interval_str, start_time, end_time, limit)
             .await?;
 
         Ok(klines
@@ -185,7 +187,7 @@ impl<R: RestClient + Clone, W: WsSession<BackpackCodec>> MarketDataSource for Ma
                 symbol: conversion::string_to_symbol(&symbol),
                 open_time: k.start.parse::<i64>().unwrap_or(0),
                 close_time: k.end.parse::<i64>().unwrap_or(0),
-                interval: interval_str.clone(),
+                interval: interval_str.to_string(),
                 open_price: conversion::string_to_price(&k.open),
                 high_price: conversion::string_to_price(&k.high),
                 low_price: conversion::string_to_price(&k.low),
@@ -266,10 +268,10 @@ impl<R: RestClient + Clone> MarketDataSource for MarketData<R, ()> {
         start_time: Option<i64>,
         end_time: Option<i64>,
     ) -> Result<Vec<Kline>, ExchangeError> {
-        let interval_str = interval.to_backpack_format();
+        let interval_str = kline_interval_to_backpack_string(interval);
         let klines = self
             .rest
-            .get_klines(&symbol, &interval_str, start_time, end_time, limit)
+            .get_klines(&symbol, interval_str, start_time, end_time, limit)
             .await?;
 
         Ok(klines
@@ -278,7 +280,7 @@ impl<R: RestClient + Clone> MarketDataSource for MarketData<R, ()> {
                 symbol: conversion::string_to_symbol(&symbol),
                 open_time: k.start.parse::<i64>().unwrap_or(0),
                 close_time: k.end.parse::<i64>().unwrap_or(0),
-                interval: interval_str.clone(),
+                interval: interval_str.to_string(),
                 open_price: conversion::string_to_price(&k.open),
                 high_price: conversion::string_to_price(&k.high),
                 low_price: conversion::string_to_price(&k.low),
@@ -291,34 +293,6 @@ impl<R: RestClient + Clone> MarketDataSource for MarketData<R, ()> {
     }
 }
 
-/// Extension trait for `KlineInterval` to support Backpack format
-pub trait BackpackKlineInterval {
-    fn to_backpack_format(&self) -> String;
-}
-
-impl BackpackKlineInterval for KlineInterval {
-    fn to_backpack_format(&self) -> String {
-        match self {
-            Self::Minutes1 => "1m".to_string(),
-            Self::Minutes3 => "3m".to_string(),
-            Self::Minutes5 => "5m".to_string(),
-            Self::Minutes15 => "15m".to_string(),
-            Self::Minutes30 => "30m".to_string(),
-            Self::Hours1 => "1h".to_string(),
-            Self::Hours2 => "2h".to_string(),
-            Self::Hours4 => "4h".to_string(),
-            Self::Hours6 => "6h".to_string(),
-            Self::Hours8 => "8h".to_string(),
-            Self::Hours12 => "12h".to_string(),
-            Self::Days1 => "1d".to_string(),
-            Self::Days3 => "3d".to_string(),
-            Self::Weeks1 => "1w".to_string(),
-            Self::Months1 => "1M".to_string(),
-            // Seconds1 removed - not commonly supported
-        }
-    }
-}
-
 /// Convert `BackpackMessage` to `MarketDataType`
 fn convert_backpack_message_to_market_data(
     message: crate::exchanges::backpack::codec::BackpackMessage,

src/exchanges/backpack/conversions.rs

@@ -1,13 +1,34 @@
 use crate::core::types::{
-    conversion, Balance, Kline, Market, MarketDataType, OrderBook, OrderBookEntry, Position,
-    PositionSide, Symbol, Ticker, Trade,
+    conversion, Balance, Kline, KlineInterval, Market, MarketDataType, OrderBook, OrderBookEntry,
+    Position, PositionSide, Symbol, Ticker, Trade,
 };
 use crate::exchanges::backpack::types::{
     BackpackBalance, BackpackMarket, BackpackOrderBook, BackpackPosition, BackpackRestKline,
     BackpackTicker, BackpackTrade, BackpackWebSocketKline, BackpackWebSocketOrderBook,
     BackpackWebSocketTicker, BackpackWebSocketTrade,
 };
 
+/// Convert kline interval to Backpack format
+pub fn kline_interval_to_backpack_string(interval: KlineInterval) -> &'static str {
+    match interval {
+        KlineInterval::Minutes1 => "1m",
+        KlineInterval::Minutes3 => "3m",
+        KlineInterval::Minutes5 => "5m",
+        KlineInterval::Minutes15 => "15m",
+        KlineInterval::Minutes30 => "30m",
+        KlineInterval::Hours1 => "1h",
+        KlineInterval::Hours2 => "2h",
+        KlineInterval::Hours4 => "4h",
+        KlineInterval::Hours6 => "6h",
+        KlineInterval::Hours8 => "8h",
+        KlineInterval::Hours12 => "12h",
+        KlineInterval::Days1 => "1d",
+        KlineInterval::Days3 => "3d",
+        KlineInterval::Weeks1 => "1w",
+        KlineInterval::Months1 => "1M",
+    }
+}
+
 /// Convert Backpack market to core Market type
 pub fn convert_market(backpack_market: BackpackMarket) -> Market {
     Market {

src/exchanges/backpack/mod.rs

@@ -7,6 +7,8 @@ pub mod builder;
 pub mod connector;
 pub mod rest;
 
+use crate::exchanges::backpack::conversions::kline_interval_to_backpack_string;
+
 // Re-export main components
 pub use builder::{
     build_connector,
@@ -48,7 +50,7 @@ pub fn create_backpack_stream_identifiers(
                 crate::core::types::SubscriptionType::Klines { interval } => {
                     streams.push(format!(
                         "kline.{}.{}",
-                        interval.to_backpack_format(),
+                        kline_interval_to_backpack_string(*interval),
                         symbol
                     ));
                 }
@@ -58,31 +60,3 @@ pub fn create_backpack_stream_identifiers(
 
     streams
 }
-
-/// Helper extension trait for `KlineInterval` to support Backpack format
-pub trait BackpackKlineInterval {
-    fn to_backpack_format(&self) -> &str;
-}
-
-impl BackpackKlineInterval for crate::core::types::KlineInterval {
-    fn to_backpack_format(&self) -> &str {
-        match self {
-            Self::Minutes1 => "1m",
-            Self::Minutes3 => "3m",
-            Self::Minutes5 => "5m",
-            Self::Minutes15 => "15m",
-            Self::Minutes30 => "30m",
-            Self::Hours1 => "1h",
-            Self::Hours2 => "2h",
-            Self::Hours4 => "4h",
-            Self::Hours6 => "6h",
-            Self::Hours8 => "8h",
-            Self::Hours12 => "12h",
-            Self::Days1 => "1d",
-            Self::Days3 => "3d",
-            Self::Weeks1 => "1w",
-            Self::Months1 => "1M",
-            // Seconds1 removed - not commonly supported
-        }
-    }
-}

src/exchanges/binance/codec.rs

@@ -1,5 +1,6 @@
 use crate::core::errors::ExchangeError;
 use crate::core::kernel::WsCodec;
+use crate::exchanges::binance::conversions::kline_interval_to_binance_string;
 use serde_json::{json, Value};
 use tokio_tungstenite::tungstenite::Message;
 
@@ -191,7 +192,7 @@ pub fn create_binance_stream_identifiers(
                     streams.push(format!(
                         "{}@kline_{}",
                         lower_symbol,
-                        interval.to_binance_format()
+                        kline_interval_to_binance_string(*interval)
                     ));
                 }
             }

src/exchanges/binance/conversions.rs

@@ -1,7 +1,7 @@
 use super::types as binance_types;
 use crate::core::types::{
-    conversion, Kline, Market, MarketDataType, OrderBook, OrderBookEntry, OrderSide, OrderType,
-    Symbol, Ticker, TimeInForce, Trade,
+    conversion, Kline, KlineInterval, Market, MarketDataType, OrderBook, OrderBookEntry, OrderSide,
+    OrderType, Symbol, Ticker, TimeInForce, Trade,
 };
 use serde_json::Value;
 
@@ -80,6 +80,27 @@ pub fn convert_time_in_force(tif: &TimeInForce) -> String {
     }
 }
 
+/// Convert kline interval to Binance format
+pub fn kline_interval_to_binance_string(interval: KlineInterval) -> &'static str {
+    match interval {
+        KlineInterval::Minutes1 => "1m",
+        KlineInterval::Minutes3 => "3m",
+        KlineInterval::Minutes5 => "5m",
+        KlineInterval::Minutes15 => "15m",
+        KlineInterval::Minutes30 => "30m",
+        KlineInterval::Hours1 => "1h",
+        KlineInterval::Hours2 => "2h",
+        KlineInterval::Hours4 => "4h",
+        KlineInterval::Hours6 => "6h",
+        KlineInterval::Hours8 => "8h",
+        KlineInterval::Hours12 => "12h",
+        KlineInterval::Days1 => "1d",
+        KlineInterval::Days3 => "3d",
+        KlineInterval::Weeks1 => "1w",
+        KlineInterval::Months1 => "1M",
+    }
+}
+
 /// Convert binance REST kline to core kline type
 pub fn convert_binance_rest_kline(
     kline: &binance_types::BinanceRestKline,
@@ -213,3 +234,25 @@ pub fn parse_websocket_message(value: Value) -> Option<MarketDataType> {
     }
     None
 }
+
+#[cfg(test)]
+mod tests {
+    use super::kline_interval_to_binance_string;
+    use crate::core::types::KlineInterval;
+
+    #[test]
+    fn kline_interval_to_binance_string_uses_exchange_format() {
+        assert_eq!(
+            kline_interval_to_binance_string(KlineInterval::Minutes1),
+            "1m"
+        );
+        assert_eq!(
+            kline_interval_to_binance_string(KlineInterval::Hours1),
+            "1h"
+        );
+        assert_eq!(
+            kline_interval_to_binance_string(KlineInterval::Months1),
+            "1M"
+        );
+    }
+}

src/exchanges/binance/rest.rs

@@ -1,6 +1,7 @@
 use crate::core::errors::ExchangeError;
 use crate::core::kernel::RestClient;
 use crate::core::types::KlineInterval;
+use crate::exchanges::binance::conversions::kline_interval_to_binance_string;
 use crate::exchanges::binance::types::{
     BinanceAccountInfo, BinanceExchangeInfo, BinanceOrderResponse, BinanceRestKline,
 };
@@ -32,8 +33,8 @@ impl<R: RestClient> BinanceRestClient<R> {
         start_time: Option<i64>,
         end_time: Option<i64>,
     ) -> Result<Vec<BinanceRestKline>, ExchangeError> {
-        let interval_str = interval.to_binance_format();
-        let mut params = vec![("symbol", symbol), ("interval", interval_str.as_str())];
+        let interval_str = kline_interval_to_binance_string(interval);
+        let mut params = vec![("symbol", symbol), ("interval", interval_str)];
 
         let limit_str;
         let start_time_str;
@@ -88,31 +89,3 @@ impl<R: RestClient> BinanceRestClient<R> {
             .await
     }
 }
-
-/// Extension trait for `KlineInterval` to support Binance format
-pub trait BinanceKlineInterval {
-    fn to_binance_format(&self) -> &str;
-}
-
-impl BinanceKlineInterval for KlineInterval {
-    fn to_binance_format(&self) -> &str {
-        match self {
-            // Seconds1 removed - not commonly supported
-            Self::Minutes1 => "1m",
-            Self::Minutes3 => "3m",
-            Self::Minutes5 => "5m",
-            Self::Minutes15 => "15m",
-            Self::Minutes30 => "30m",
-            Self::Hours1 => "1h",
-            Self::Hours2 => "2h",
-            Self::Hours4 => "4h",
-            Self::Hours6 => "6h",
-            Self::Hours8 => "8h",
-            Self::Hours12 => "12h",
-            Self::Days1 => "1d",
-            Self::Days3 => "3d",
-            Self::Weeks1 => "1w",
-            Self::Months1 => "1M",
-        }
-    }
-}

src/exchanges/binance_perp/codec.rs

@@ -1,5 +1,6 @@
 use crate::core::errors::ExchangeError;
 use crate::core::kernel::WsCodec;
+use crate::exchanges::binance_perp::conversions::kline_interval_to_binance_perp_string;
 use serde_json::{json, Value};
 use tokio_tungstenite::tungstenite::Message;
 
@@ -213,7 +214,7 @@ pub fn create_binance_perp_stream_identifiers(
                     streams.push(format!(
                         "{}@kline_{}",
                         lower_symbol,
-                        interval.to_binance_format()
+                        kline_interval_to_binance_perp_string(*interval)
                     ));
                 }
             }