From 29cbd5a6adf1bf13c9c4594fa740fdec4fa85ed7 Mon Sep 17 00:00:00 2001
From: WeiCHEN <weichen@WeiCHENdeMac-mini.local>
Date: Fri, 11 Sep 2026 13:20:13 +0800
Subject: [PATCH] feat(web): isolate stream runtime by session and turn

Co-authored-by: Cursor <cursoragent@cursor.com>
---
 web/src/hooks/useTurnRuntime.test.ts |  46 +++++++++
 web/src/hooks/useTurnRuntime.ts      | 145 +++++++++++++++++++++++++++
 2 files changed, 191 insertions(+)
 create mode 100644 web/src/hooks/useTurnRuntime.test.ts
 create mode 100644 web/src/hooks/useTurnRuntime.ts

diff --git a/web/src/hooks/useTurnRuntime.test.ts b/web/src/hooks/useTurnRuntime.test.ts
new file mode 100644
index 00000000..efb11b11
--- /dev/null
+++ b/web/src/hooks/useTurnRuntime.test.ts
@@ -0,0 +1,46 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+
+test('turn runtime: session A stream survives session B switch', () => {
+  type TurnRuntime = {
+    clientTurnId: string;
+    sessionId: string;
+    status: string;
+    controller: { aborted: boolean };
+  };
+  const store = new Map<string, Map<string, TurnRuntime>>();
+
+  const register = (rt: TurnRuntime) => {
+    if (!store.has(rt.sessionId)) store.set(rt.sessionId, new Map());
+    store.get(rt.sessionId)!.set(rt.clientTurnId, rt);
+  };
+
+  const isSessionThinking = (sessionId: string) => {
+    const m = store.get(sessionId);
+    if (!m) return false;
+    for (const rt of m.values()) {
+      if (rt.status === 'pending' || rt.status === 'streaming') return true;
+    }
+    return false;
+  };
+
+  register({
+    clientTurnId: 'turn-a',
+    sessionId: 'session-A',
+    status: 'streaming',
+    controller: { aborted: false },
+  });
+
+  assert.equal(isSessionThinking('session-A'), true);
+  assert.equal(isSessionThinking('session-B'), false);
+
+  register({
+    clientTurnId: 'turn-b',
+    sessionId: 'session-B',
+    status: 'pending',
+    controller: { aborted: false },
+  });
+
+  assert.equal(isSessionThinking('session-A'), true);
+  assert.equal(isSessionThinking('session-B'), true);
+});
diff --git a/web/src/hooks/useTurnRuntime.ts b/web/src/hooks/useTurnRuntime.ts
new file mode 100644
index 00000000..cf66589e
--- /dev/null
+++ b/web/src/hooks/useTurnRuntime.ts
@@ -0,0 +1,145 @@
+import { useCallback, useRef, useSyncExternalStore } from 'react';
+
+export type TurnRuntimeStatus =
+  | 'pending'
+  | 'streaming'
+  | 'completed'
+  | 'failed'
+  | 'cancelled';
+
+export interface TurnRuntime {
+  clientTurnId: string;
+  sessionId: string;
+  userMsgId: string;
+  asstId: string;
+  status: TurnRuntimeStatus;
+  controller: AbortController;
+  startedAt: number;
+}
+
+type Listener = () => void;
+
+/** 按 sessionId → clientTurnId 隔离流运行态 */
+export function useTurnRuntime(activeSessionId: string) {
+  const storeRef = useRef({
+    turns: new Map<string, Map<string, TurnRuntime>>(),
+    listeners: new Set<Listener>(),
+  });
+
+  const subscribe = useCallback((listener: Listener) => {
+    storeRef.current.listeners.add(listener);
+    return () => {
+      storeRef.current.listeners.delete(listener);
+    };
+  }, []);
+
+  const notify = useCallback(() => {
+    for (const l of storeRef.current.listeners) {
+      l();
+    }
+  }, []);
+
+  const getSessionMap = useCallback((sessionId: string) => {
+    const store = storeRef.current;
+    if (!store.turns.has(sessionId)) {
+      store.turns.set(sessionId, new Map());
+    }
+    return store.turns.get(sessionId)!;
+  }, []);
+
+  const registerTurn = useCallback(
+    (runtime: TurnRuntime) => {
+      const sessionMap = getSessionMap(runtime.sessionId);
+      // 同 session 新 turn 开始前，仅中止该 session 内仍在 pending/streaming 的旧 turn
+      for (const [turnId, existing] of sessionMap) {
+        if (
+          turnId !== runtime.clientTurnId &&
+          (existing.status === 'pending' || existing.status === 'streaming')
+        ) {
+          existing.controller.abort();
+          existing.status = 'cancelled';
+        }
+      }
+      sessionMap.set(runtime.clientTurnId, runtime);
+      notify();
+    },
+    [getSessionMap, notify],
+  );
+
+  const updateTurnStatus = useCallback(
+    (sessionId: string, clientTurnId: string, status: TurnRuntimeStatus) => {
+      const rt = getSessionMap(sessionId).get(clientTurnId);
+      if (rt) {
+        rt.status = status;
+        notify();
+      }
+    },
+    [getSessionMap, notify],
+  );
+
+  const removeTurn = useCallback(
+    (sessionId: string, clientTurnId: string) => {
+      getSessionMap(sessionId).delete(clientTurnId);
+      notify();
+    },
+    [getSessionMap, notify],
+  );
+
+  const abortTurn = useCallback(
+    (sessionId: string, clientTurnId: string) => {
+      const rt = getSessionMap(sessionId).get(clientTurnId);
+      if (rt) {
+        rt.controller.abort();
+        rt.status = 'cancelled';
+        notify();
+      }
+    },
+    [getSessionMap, notify],
+  );
+
+  const abortActiveSessionTurns = useCallback(() => {
+    const sessionMap = getSessionMap(activeSessionId);
+    for (const rt of sessionMap.values()) {
+      if (rt.status === 'pending' || rt.status === 'streaming') {
+        rt.controller.abort();
+        rt.status = 'cancelled';
+      }
+    }
+    notify();
+  }, [activeSessionId, getSessionMap, notify]);
+
+  const isSessionThinking = useCallback(
+    (sessionId: string) => {
+      const sessionMap = storeRef.current.turns.get(sessionId);
+      if (!sessionMap) return false;
+      for (const rt of sessionMap.values()) {
+        if (rt.status === 'pending' || rt.status === 'streaming') return true;
+      }
+      return false;
+    },
+    [],
+  );
+
+  const isThinking = useSyncExternalStore(
+    subscribe,
+    () => isSessionThinking(activeSessionId),
+    () => false,
+  );
+
+  const getTurn = useCallback(
+    (sessionId: string, clientTurnId: string) =>
+      storeRef.current.turns.get(sessionId)?.get(clientTurnId),
+    [],
+  );
+
+  return {
+    registerTurn,
+    updateTurnStatus,
+    removeTurn,
+    abortTurn,
+    abortActiveSessionTurns,
+    isThinking,
+    isSessionThinking,
+    getTurn,
+  };
+}