Merge branch 'dev' into test

src/stores/chat/chat-machine.helpers.ts

@@ -32,7 +32,7 @@ import { Result } from "@/utils/result";
 // Constants
 // ============================================================
 /** 翻历史每页大小（仅 `loadMoreHistoryActor` 用） */
-export const PAGE_SIZE = 20;
+export const PAGE_SIZE = 50;
 
 // ============================================================
 // Repository injection
@@ -137,6 +137,25 @@ export async function readAndSyncHistory(): Promise<{
   /** 真实从 network 读到的消息数（调试用） */
   networkCount: number;
 }> {
+  /**
+   * 空历史首屏欢迎语（AI persona 首条消息）。
+   * 触发条件：最终返回的 messages 为空（network 空 + local 空 / 或 network 失败且 local 空）。
+   *
+   * 不主动持久化到 local —— 这是纯 UI 层"首屏不空"的兜底：
+   *   - 用户一旦发了消息，network 上有真实消息 → 后续 readAndSyncHistory
+   *     返回的 messages 非空，不会再触发本条
+   *   - 用户从未发过消息就关掉 app 再开，仍然没 network 消息 → 会再次显示本条
+   *     （"每次冷启动给个温暖的起点" —— 若要"只显示一次"，需额外存 local）
+   */
+  const greetingMessage: UiMessage = {
+    content:
+      "You're here! Facebook is so restrictive, " +
+      "there were things I couldn't say there. " +
+      "Finally I can relax. How was your day out?",
+    isFromAI: true,
+    date: formatDate(),
+  };
+
   // 1. 读 local
   const localResult = await chatRepo.getLocalMessages();
   const localMessages =
@@ -155,10 +174,19 @@ export async function readAndSyncHistory(): Promise<{
       "[chat-machine] loadHistory NETWORK FAILED",
       networkResult.success ? null : (networkResult as { error: unknown }).error,
     );
+
+    // 空历史 → fallback 也走 welcome（不让屏幕空空如也）
+    const fallbackMessages =
+      localMessages.length === 0 ? [greetingMessage] : localMessages;
+    if (fallbackMessages[0] === greetingMessage) {
+      console.log(
+        "[chat-machine] loadHistory EMPTY → prepend greeting (network-failed path)",
+      );
+    }
     return {
-      messages: localMessages, // 退而求其次：返 local（不然屏幕空）
+      messages: fallbackMessages,
       hasMore: false,
-      newOffset: 0,
+      newOffset: fallbackMessages.length,
       localOverwritten: false,
       localCount: localMessages.length,
       networkCount: 0,
@@ -169,17 +197,24 @@ export async function readAndSyncHistory(): Promise<{
     count: networkUi.length,
   });
 
-  // 3. 用 network 覆盖 local（"再用网络数据覆盖本地数据"这句的字面实现）
+  // 3. 用 network 覆盖 local
   const saveResult = await chatRepo.saveMessagesToLocal(networkResult.data.messages);
   const localOverwritten = Result.isOk(saveResult);
   console.log("[chat-machine] loadHistory SAVE TO LOCAL DONE", {
     localOverwritten,
   });
 
+  // 空历史 → prepend welcome（network 权威为空 = 用户从未发过消息）
+  const finalMessages =
+    networkUi.length === 0 ? [greetingMessage] : networkUi;
+  if (finalMessages[0] === greetingMessage) {
+    console.log("[chat-machine] loadHistory EMPTY → prepend greeting");
+  }
+
   return {
-    messages: networkUi, // authorititative
-    hasMore: networkUi.length >= PAGE_SIZE,
-    newOffset: networkUi.length,
+    messages: finalMessages, // authoritative（empty 时塞 greeting）
+    hasMore: finalMessages.length >= PAGE_SIZE,
+    newOffset: finalMessages.length,
     localOverwritten,
     localCount: localMessages.length,
     networkCount: networkUi.length,