refactor(chat): centralize session persistence

src/routes/chat.ts

@@ -36,6 +36,7 @@ import {
   type ActiveRun,
   type RunStatus,
   type StreamSubscriber,
+  appendBackendToolArtifact,
   cancelBackendTodos,
   completeBackendProgress,
   createInitialStreamingMessages,
@@ -67,12 +68,6 @@ const forkPayloadSchema = z.object({
   keep_message_count: z.coerce.number().int().min(0),
 });
 
-const sessionStateSchema = z.object({
-  title: z.string().max(120).optional(),
-  is_title_manually_edited: z.boolean().optional(),
-  messages: z.array(z.unknown()).default([]),
-});
-
 const activeRuns = new Map<string, ActiveRun>();
 const lastRunStatuses = new Map<string, RunStatus>();
 
@@ -80,6 +75,20 @@ const toSessionUiStateContext = (sessionRecord: SessionRecord) => ({
   sessionId: sessionRecord.sessionId,
 });
 
+export const buildForkedSessionUiState = (
+  sourceState: { messages?: unknown[] } | null | undefined,
+  input: {
+    keepMessageCount: number;
+    targetSessionId: string;
+  },
+) => ({
+  sessionId: input.targetSessionId,
+  isTitleManuallyEdited: false,
+  messages: Array.isArray(sourceState?.messages)
+    ? sourceState.messages.slice(0, input.keepMessageCount)
+    : [],
+});
+
 const getSessionRunStatus = (sessionId: string) =>
   activeRuns.get(sessionId)?.status ?? lastRunStatuses.get(sessionId);
 
@@ -274,71 +283,6 @@ export const buildChatRouter = (
     res.on("close", cleanup);
   });
 
-  chatRouter.put("/session/:sessionId", async (req, res) => {
-    const sessionId = req.params.sessionId?.trim();
-    const parsed = sessionStateSchema.safeParse(req.body ?? {});
-    if (!parsed.success) {
-      res.status(400).json({
-        message: "invalid request payload",
-        detail: parsed.error.flatten(),
-      });
-      return;
-    }
-
-    const projectId = req.header("x-project-id") ?? undefined;
-    const userId = req.header("x-user-id") ?? undefined;
-    const actorKey = toActorKey(userId);
-    const projectKey = toProjectKey(projectId);
-    if (!sessionId) {
-      res.status(400).json({ message: "session_id is required" });
-      return;
-    }
-
-    const { record } = await sessionMetadataStore.ensure({
-      actorKey,
-      projectId,
-      projectKey,
-      sessionId,
-      userId,
-    });
-    const nextRecord = await sessionMetadataStore.touch(record, {
-      ...(parsed.data.title ? { title: parsed.data.title } : {}),
-    });
-    await sessionUiStateStore.write(toSessionUiStateContext(nextRecord), {
-      sessionId: nextRecord.sessionId,
-      isTitleManuallyEdited: parsed.data.is_title_manually_edited,
-      messages: parsed.data.messages,
-    });
-    const latestTurn = extractLatestFrontendTurn(parsed.data.messages);
-    if (latestTurn) {
-      void learningOrchestrator.onTurnCompleted({
-        ...latestTurn,
-        requestContext: {
-          actorKey,
-          clientSessionId: nextRecord.sessionId,
-          projectId,
-          projectKey,
-          traceId: req.header("x-trace-id") ?? `save-${nextRecord.sessionId}`,
-          userId,
-        },
-        sessionId: nextRecord.sessionId,
-      }).catch((error) => {
-        logger.warn(
-          { err: error, sessionId: nextRecord.sessionId },
-          "post-save learning failed",
-        );
-      });
-    }
-    res.json({
-      id: nextRecord.sessionId,
-      title: nextRecord.title ?? "新对话",
-      created_at: nextRecord.createdAt,
-      updated_at: nextRecord.updatedAt,
-      status: nextRecord.status,
-      session_id: nextRecord.sessionId,
-    });
-  });
-
   chatRouter.patch("/session/:sessionId/title", async (req, res) => {
     const sessionId = req.params.sessionId?.trim();
     const title =
@@ -469,7 +413,7 @@ export const buildChatRouter = (
       });
       const nextSessionId = targetSessionRecord.sessionId;
 
-      if (sourceSessionId && parsed.data.keep_message_count > 0) {
+      if (sourceSessionId) {
         await sessionTranscriptStore.cloneThread(
           {
             actorKey,
@@ -485,12 +429,24 @@ export const buildChatRouter = (
           },
           parsed.data.keep_message_count,
         );
-        if (sourceSessionRecord?.title) {
-          await sessionMetadataStore.touch(targetSessionRecord, {
-            title: sourceSessionRecord.title,
-          });
-        }
       }
+      const sourceState = sourceSessionRecord
+        ? await sessionUiStateStore.read(toSessionUiStateContext(sourceSessionRecord))
+        : null;
+      const forkTitle = sourceSessionRecord?.title
+        ? `${sourceSessionRecord.title} 副本`
+        : "新对话副本";
+      const titledTargetSessionRecord = await sessionMetadataStore.touch(
+        targetSessionRecord,
+        { title: forkTitle },
+      );
+      await sessionUiStateStore.write(
+        toSessionUiStateContext(titledTargetSessionRecord),
+        buildForkedSessionUiState(sourceState, {
+          keepMessageCount: parsed.data.keep_message_count,
+          targetSessionId: nextSessionId,
+        }),
+      );
 
       logger.info(
         {
@@ -789,6 +745,11 @@ export const buildChatRouter = (
             ...message,
             todos: upsertBackendTodoUpdate(message.todos, payload),
           }));
+        } else if (event === "tool_call") {
+          activeRun.messages = updateLastAssistantMessage(activeRun.messages, (message) => ({
+            ...message,
+            artifacts: appendBackendToolArtifact(message.artifacts, data),
+          }));
         }
 
         for (const subscriber of activeRun.subscribers) {
@@ -876,6 +837,19 @@ export const buildChatRouter = (
               logger.warn({ err: error, sessionId: clientSessionId }, "failed to persist chat stream state");
             });
           }
+          const latestTurn = extractLatestFrontendTurn(activeRun.messages);
+          if (latestTurn) {
+            void learningOrchestrator.onTurnCompleted({
+              ...latestTurn,
+              requestContext,
+              sessionId: clientSessionId,
+            }).catch((error) => {
+              logger.warn(
+                { err: error, sessionId: clientSessionId },
+                "stream-completed learning failed",
+              );
+            });
+          }
         }
       } finally {
         if (abortController.signal.aborted) {