feat(FN-1857): merge fusion/fn-1857

packages/dashboard/app/hooks/__tests__/useChat.test.ts

@@ -121,6 +121,61 @@ describe("useChat", () => {
     });
   });
 
+  it("loads BOTH user and assistant messages when selecting a session", async () => {
+    // This test verifies the fix for FN-1857: Chat assistant messages not persisted
+    // after navigating away. The selectSession should fetch ALL messages from the server,
+    // including both user and assistant messages.
+    const session = makeSession({ id: "session-001", agentId: "agent-001" });
+    mockFetchChatSessions.mockResolvedValueOnce({ sessions: [session] });
+
+    // Simulate a conversation with multiple user and assistant messages
+    // Note: The hook calls reverse() on the messages array, so we provide them in reverse order
+    mockFetchChatMessages.mockResolvedValueOnce({
+      messages: [
+        makeMessage({ id: "msg-004", sessionId: "session-001", role: "assistant", content: "Second answer" }),
+        makeMessage({ id: "msg-003", sessionId: "session-001", role: "user", content: "Second question" }),
+        makeMessage({ id: "msg-002", sessionId: "session-001", role: "assistant", content: "First answer" }),
+        makeMessage({ id: "msg-001", sessionId: "session-001", role: "user", content: "First question" }),
+      ],
+    });
+
+    const { result } = renderHook(() => useChat());
+
+    await waitFor(() => {
+      expect(result.current.sessions).toHaveLength(1);
+    });
+
+    act(() => {
+      result.current.selectSession("session-001");
+    });
+
+    await waitFor(() => {
+      expect(result.current.messages).toHaveLength(4);
+    });
+
+    // Verify all messages are loaded in correct order
+    expect(result.current.messages[0]).toMatchObject({
+      id: "msg-001",
+      role: "user",
+      content: "First question",
+    });
+    expect(result.current.messages[1]).toMatchObject({
+      id: "msg-002",
+      role: "assistant",
+      content: "First answer",
+    });
+    expect(result.current.messages[2]).toMatchObject({
+      id: "msg-003",
+      role: "user",
+      content: "Second question",
+    });
+    expect(result.current.messages[3]).toMatchObject({
+      id: "msg-004",
+      role: "assistant",
+      content: "Second answer",
+    });
+  });
+
   it("creates a new session and selects it", async () => {
     const newSession = makeSession({ id: "session-new", agentId: "agent-001", title: "Test Chat" });
     mockCreateChatSession.mockResolvedValueOnce({ session: newSession });

packages/dashboard/app/hooks/useQuickChat.ts

@@ -32,6 +32,7 @@ export interface UseQuickChatReturn {
   sendMessage: (content: string) => Promise<void>;
   switchSession: (agentId: string) => Promise<void>;
   loadMessages: () => Promise<void>;
+  reloadMessages: () => Promise<void>;
 }
 
 /**
@@ -114,11 +115,23 @@ export function useQuickChat(
     }
   }, [activeSession, loadMessages]);
 
+  // Reload messages from server (for same-agent revisit)
+  const reloadMessages = useCallback(async () => {
+    if (!activeSession) return;
+    setMessagesLoading(true);
+    try {
+      const data = await fetchChatMessages(activeSession.id, { limit: 50 }, projectId);
+      setMessages(data.messages.reverse());
+    } catch (err) {
+      console.error("[useQuickChat] Failed to reload messages:", err);
+    } finally {
+      setMessagesLoading(false);
+    }
+  }, [activeSession, projectId]);
+
   // Switch to a different agent's session
   const switchSession = useCallback(
     async (agentId: string) => {
-      if (agentId === currentAgentIdRef.current) return;
-
       // Close any existing stream
       if (streamRef.current) {
         streamRef.current.close();
@@ -130,10 +143,17 @@ export function useQuickChat(
       setStreamingThinking("");
       setIsStreaming(false);
 
-      // Initialize session for new agent
+      if (agentId === currentAgentIdRef.current) {
+        // Same agent — just reload messages from server
+        await reloadMessages();
+        return;
+      }
+
+      // New agent — initialize session
+      currentAgentIdRef.current = agentId;
       await initializeSession(agentId);
     },
-    [initializeSession],
+    [initializeSession, reloadMessages],
   );
 
   // Send a message using SSE streaming
@@ -232,5 +252,6 @@ export function useQuickChat(
     sendMessage,
     switchSession,
     loadMessages,
+    reloadMessages,
   };
 }