重建会话记录逻辑

src/routes/chatSession.ts

@@ -254,6 +254,46 @@ const isObjectRecord = (value: unknown): value is Record<string, unknown> =>
 const isSyntheticAssistantError = (content: string) =>
   /^⚠️\s*\*\*(请求已中断|错误[:：]?)/.test(content);
 
+export const extractLatestFrontendTurn = (messages: unknown[] | undefined) => {
+  if (!Array.isArray(messages) || messages.length === 0) {
+    return null;
+  }
+
+  for (let index = messages.length - 1; index >= 0; index -= 1) {
+    const assistant = messages[index];
+    if (!isObjectRecord(assistant) || assistant.role !== "assistant") {
+      continue;
+    }
+    const assistantMessage =
+      typeof assistant.content === "string"
+        ? assistant.content.replace(/\s+/g, " ").trim()
+        : "";
+    if (!assistantMessage || isSyntheticAssistantError(assistantMessage)) {
+      continue;
+    }
+
+    const user = messages
+      .slice(0, index)
+      .reverse()
+      .find((message) => isObjectRecord(message) && message.role === "user");
+    if (!isObjectRecord(user) || typeof user.content !== "string") {
+      continue;
+    }
+    const userMessage = user.content.replace(/\s+/g, " ").trim();
+    if (!userMessage) {
+      continue;
+    }
+
+    return {
+      assistantMessage,
+      toolCallCount: estimateFrontendToolCallCount(assistant),
+      userMessage,
+    };
+  }
+
+  return null;
+};
+
 const buildRestoredConversationFromMessages = (messages: unknown[] | undefined) => {
   if (!Array.isArray(messages) || messages.length === 0) {
     return "";
@@ -299,4 +339,16 @@ const buildRestoredConversationFromMessages = (messages: unknown[] | undefined)
     "以下为当前前端对话线程中最近的历史对话，请延续其中已确认的目标、约束、结论与引用结果。",
     trimmedConversation,
   ].join("\n");
-};
+};
+
+const estimateFrontendToolCallCount = (assistant: Record<string, unknown>) => {
+  const progress = Array.isArray(assistant.progress) ? assistant.progress : [];
+  const artifacts = Array.isArray(assistant.artifacts) ? assistant.artifacts : [];
+  const toolProgressCount = progress.filter(
+    (item) =>
+      isObjectRecord(item) &&
+      (item.phase === "tool" ||
+        (typeof item.id === "string" && item.id.startsWith("tool-"))),
+  ).length;
+  return Math.max(toolProgressCount, artifacts.length);
+};