refactor(LocalDataSource, PostRepository, ChatScreen): enhance database handling and message loading

- Introduced a promise-based initialization mechanism in LocalDataSource to prevent concurrent initialization issues.
- Updated PostRepository to utilize an enqueueWrite method for database operations, ensuring thread-safe writes.
- Refactored ChatScreen to improve message loading logic, including preloading history and managing scroll behavior more effectively.
- Enhanced message rendering logic to maintain correct indices in inverted lists and optimize user experience during scrolling.

src/data/datasources/LocalDataSource.ts

@@ -20,6 +20,7 @@ export class LocalDataSource implements ILocalDataSource {
   private db: SQLite.SQLiteDatabase | null = null;
   private dbName: string;
   private initialized = false;
+  private initializingPromise: Promise<void> | null = null;
 
   constructor(config: LocalDataSourceConfig = {}) {
     // 如果提供了userId，使用用户专属数据库
@@ -34,6 +35,21 @@ export class LocalDataSource implements ILocalDataSource {
       return;
     }
 
+    // 防止并发初始化导致连接状态竞争
+    if (this.initializingPromise) {
+      await this.initializingPromise;
+      return;
+    }
+
+    this.initializingPromise = this.doInitialize();
+    try {
+      await this.initializingPromise;
+    } finally {
+      this.initializingPromise = null;
+    }
+  }
+
+  private async doInitialize(): Promise<void> {
     try {
       // 使用全局实例管理
       if (dbInstance && currentDbName === this.dbName) {
@@ -227,6 +243,17 @@ export class LocalDataSource implements ILocalDataSource {
       }
       return await db.runAsync(sql);
     } catch (error) {
+      if (this.isRecoverableError(error)) {
+        this.db = null;
+        this.initialized = false;
+        dbInstance = null;
+        await this.initialize();
+        const db = this.ensureDb();
+        if (params && params.length > 0) {
+          return await db.runAsync(sql, params as any);
+        }
+        return await db.runAsync(sql);
+      }
       this.handleError(error, 'RUN');
     }
   }

src/data/repositories/PostRepository.ts

@@ -195,10 +195,12 @@ export class PostRepository implements IPostRepository {
   private async saveToLocalCache(post: Post): Promise<void> {
     try {
       await this.localDb.initialize();
-      await this.localDb.run(
-        `INSERT OR REPLACE INTO posts_cache (id, data, updatedAt) VALUES (?, ?, ?)`,
-        [post.id, JSON.stringify(post), new Date().toISOString()]
-      );
+      await this.localDb.enqueueWrite(async () => {
+        await this.localDb.run(
+          `INSERT OR REPLACE INTO posts_cache (id, data, updatedAt) VALUES (?, ?, ?)`,
+          [post.id, JSON.stringify(post), new Date().toISOString()]
+        );
+      });
     } catch (error) {
       console.error('[PostRepository] 保存本地缓存失败:', error);
     }
@@ -210,7 +212,9 @@ export class PostRepository implements IPostRepository {
   private async clearLocalCache(id: string): Promise<void> {
     try {
       await this.localDb.initialize();
-      await this.localDb.run('DELETE FROM posts_cache WHERE id = ?', [id]);
+      await this.localDb.enqueueWrite(async () => {
+        await this.localDb.run('DELETE FROM posts_cache WHERE id = ?', [id]);
+      });
     } catch (error) {
       console.error('[PostRepository] 清除本地缓存失败:', error);
     }
@@ -545,7 +549,9 @@ export class PostRepository implements IPostRepository {
     this.memoryCache.clear();
     try {
       await this.localDb.initialize();
-      await this.localDb.run('DELETE FROM posts_cache');
+      await this.localDb.enqueueWrite(async () => {
+        await this.localDb.run('DELETE FROM posts_cache');
+      });
     } catch (error) {
       console.error('[PostRepository] 清除所有缓存失败:', error);
     }