feat(FN-4583): complete Step 4 — fetch newest chat room message window

Fusion-Task-Id: FN-4583
Fusion-Task-Lineage: 4d9b088d-a705-4376-b547-15b37e5370aa

packages/dashboard/app/api/__tests__/chat-rooms-api.test.ts

@@ -73,7 +73,7 @@ describe("chat room legacy API client", () => {
   it("builds message endpoints", async () => {
     const fetchMock = vi.spyOn(globalThis, "fetch").mockImplementation(async () => jsonResponse({ success: true }));
 
-    await fetchChatRoomMessages("room-1", { limit: 2, offset: 1, before: "2026-01-01" }, "proj-3");
+    await fetchChatRoomMessages("room-1", { limit: 2, offset: 1, before: "2026-01-01", order: "desc" }, "proj-3");
     await postChatRoomMessage("room-1", { content: "hello", mentions: ["agent-x"] }, "proj-3");
     await deleteChatRoomMessage("room-1", "msg-1", "proj-3");
 
@@ -83,6 +83,7 @@ describe("chat room legacy API client", () => {
     expect(listUrl).toContain("limit=2");
     expect(listUrl).toContain("offset=1");
     expect(listUrl).toContain("before=2026-01-01");
+    expect(listUrl).toContain("order=desc");
 
     const [, postInit] = fetchMock.mock.calls[1] as [string, RequestInit];
     expect(postInit.method).toBe("POST");
@@ -91,4 +92,14 @@ describe("chat room legacy API client", () => {
     const [, delInit] = fetchMock.mock.calls[2] as [string, RequestInit];
     expect(delInit.method).toBe("DELETE");
   });
+
+  it("omits order param when undefined", async () => {
+    const fetchMock = vi.spyOn(globalThis, "fetch").mockImplementation(async () => jsonResponse({ messages: [] }));
+
+    await fetchChatRoomMessages("room-1", { limit: 2 }, "proj-3");
+
+    const [listUrl] = fetchMock.mock.calls[0] as [string, RequestInit];
+    expect(listUrl).toContain("limit=2");
+    expect(listUrl).not.toContain("order=");
+  });
 });

packages/dashboard/app/api/legacy.ts

@@ -8466,13 +8466,14 @@ export function removeChatRoomMember(id: string, agentId: string, projectId?: st
 
 export function fetchChatRoomMessages(
   id: string,
-  opts?: { limit?: number; offset?: number; before?: string },
+  opts?: { limit?: number; offset?: number; before?: string; order?: "asc" | "desc" },
   projectId?: string,
 ): Promise<ChatRoomMessageListResponse> {
   const search = new URLSearchParams();
   if (opts?.limit !== undefined) search.set("limit", String(opts.limit));
   if (opts?.offset !== undefined) search.set("offset", String(opts.offset));
   if (opts?.before) search.set("before", opts.before);
+  if (opts?.order) search.set("order", opts.order);
   const qs = search.toString();
   return api<ChatRoomMessageListResponse>(
     withProjectId(`/chat/rooms/${encodeURIComponent(id)}/messages${qs ? `?${qs}` : ""}`, projectId),

packages/dashboard/app/hooks/useChatRooms.ts

@@ -102,7 +102,7 @@ export function useChatRooms(
     try {
       const [membersData, messagesData] = await Promise.all([
         fetchChatRoomMembers(room.id, projectId),
-        fetchChatRoomMessages(room.id, { limit: 100 }, projectId),
+        fetchChatRoomMessages(room.id, { limit: 100, order: "desc" }, projectId),
       ]);
       setActiveRoomMembers(membersData.members);
       setMessages(messagesData.messages);
@@ -208,14 +208,14 @@ export function useChatRooms(
           message.id === optimisticMessage.id ? postResult.message : message));
       }
 
-      const latestMessages = await fetchChatRoomMessages(roomId, { limit: 100 }, projectId);
+      const latestMessages = await fetchChatRoomMessages(roomId, { limit: 100, order: "desc" }, projectId);
       if (activeRoomRef.current?.id !== roomId) {
         return;
       }
       setMessages(latestMessages.messages);
     } catch (error) {
       try {
-        const latestMessages = await fetchChatRoomMessages(roomId, { limit: 100 }, projectId);
+        const latestMessages = await fetchChatRoomMessages(roomId, { limit: 100, order: "desc" }, projectId);
         if (activeRoomRef.current?.id === roomId) {
           setMessages(latestMessages.messages);
         }

packages/dashboard/src/__tests__/chat-room-routes.test.ts

@@ -258,6 +258,10 @@ describe("Chat Room API Routes", () => {
     expect(page.status).toBe(200);
     expect((page.body as any).messages.map((m: any) => m.id)).toEqual([m2.id, m3.id]);
 
+    const newestPage = await request(app, "GET", `/api/chat/rooms/${room.id}/messages?limit=2&order=desc`);
+    expect(newestPage.status).toBe(200);
+    expect((newestPage.body as any).messages.map((m: any) => m.id)).toEqual([m2.id, m3.id]);
+
     const del1 = await request(app, "DELETE", `/api/chat/rooms/${room.id}/messages/${m1.id}`);
     expect(del1.status).toBe(200);
 

packages/dashboard/src/routes/register-chat-room-routes.ts

@@ -251,15 +251,23 @@ export function registerChatRoomRoutes(ctx: ApiRoutesContext): void {
       const room = chatStore.getRoom(roomId);
       if (!room) throw notFound(`Chat room ${roomId} not found`);
 
-      const { limit: limitStr, offset: offsetStr, before } = req.query as { limit?: string; offset?: string; before?: string };
+      const { limit: limitStr, offset: offsetStr, before, order: orderStr } = req.query as {
+        limit?: string;
+        offset?: string;
+        before?: string;
+        order?: string;
+      };
       const limit = limitStr !== undefined ? parseInt(String(limitStr), 10) : 50;
       const offset = offsetStr !== undefined ? parseInt(String(offsetStr), 10) : 0;
+      const order = orderStr === undefined ? "asc" : String(orderStr);
       if (!Number.isFinite(limit) || limit < 1) throw badRequest("limit must be a positive integer");
       if (!Number.isFinite(offset) || offset < 0) throw badRequest("offset must be a non-negative integer");
+      if (order !== "asc" && order !== "desc") throw badRequest("order must be either asc or desc");
 
       const messages = chatStore.getRoomMessages(roomId, {
         limit,
         offset,
+        order,
         ...(before ? { before } : {}),
       });