refactor(message): implement atomic message merging and patching to prevent race conditions

Introduce `mergeMessages` and `patchMessages` to the message store to handle
updates atomically within Zustand's `set` callback. This replaces manual
read-modify-write patterns in services, preventing message loss during
concurrent WebSocket updates and synchronization processes.

- Add `mergeMessages` for atomic merging of new messages into existing lists
- Add `patchMessages` for efficient field updates (e.g., sender info, status)
- Update `MessageSendService`, `MessageSyncService`, and `WSMessageHandler`
  to use these new atomic operations
- Remove reliance on external `mergeMessagesById` in service layers to
  ensure state consistency

src/stores/message/services/MessageSendService.ts

@@ -7,7 +7,7 @@ import type { MessageResponse, MessageSegment, ConversationResponse } from '../.
 import { messageService } from '@/services/message';
 import { messageRepository } from '@/database';
 import type { IMessageSendService } from '../types';
-import { useMessageStore, mergeMessagesById } from '../store';
+import { useMessageStore } from '../store';
 
 export class MessageSendService implements IMessageSendService {
   private getCurrentUserId: () => string | null;
@@ -36,8 +36,7 @@ export class MessageSendService implements IMessageSendService {
       if (response) {
         const currentUserId = this.getCurrentUserId();
         
-        // 添加到本地消息列表
+        // 原子性合并新消息到内存（防止并发 WS 消息丢失）
-        const existingMessages = store.getMessages(conversationId);
         const newMessage: MessageResponse = {
           id: response.id,
           conversation_id: conversationId,
@@ -48,8 +47,7 @@ export class MessageSendService implements IMessageSendService {
           status: 'normal',
         };
 
-        const updatedMessages = mergeMessagesById(existingMessages, [newMessage]);
+        store.mergeMessages(conversationId, [newMessage]);
-        store.setMessages(conversationId, updatedMessages);
 
         // 更新会话最后消息
         this.updateConversationWithNewMessage(conversationId, newMessage);

src/stores/message/services/MessageSyncService.ts

@@ -14,7 +14,7 @@ import {
   CONVERSATION_LIST_PAGE_SIZE,
 } from '../sources';
 import type { IMessageSyncService, MessageManagerConversationListDeps, IUserCacheService } from '../types';
-import { useMessageStore, normalizeConversationId, mergeMessagesById } from '../store';
+import { useMessageStore, normalizeConversationId } from '../store';
 import { ReadReceiptManager } from './ReadReceiptManager';
 
 export class MessageSyncService implements IMessageSyncService {
@@ -190,15 +190,10 @@ export class MessageSyncService implements IMessageSyncService {
     store.setLoadingMessages(conversationId, true);
 
     try {
-      const existingMessagesAtStart = store.getMessages(conversationId);
-      const hasInMemoryMessages = existingMessagesAtStart.length > 0;
-      let baselineMaxSeq = hasInMemoryMessages
-        ? existingMessagesAtStart.reduce((max, m) => Math.max(max, m.seq || 0), 0)
-        : 0;
-
       if (!afterSeq) {
-        // 先从本地数据库加载
+        // 先从本地数据库加载（使用 merge 避免 WS 消息丢失）
-        if (!hasInMemoryMessages) {
+        const existingMessagesAtStart = store.getMessages(conversationId);
+        if (existingMessagesAtStart.length === 0) {
           try {
             const localMessages = await messageRepository.getByConversation(conversationId, 20);
 
@@ -213,9 +208,8 @@ export class MessageSyncService implements IMessageSyncService {
                 created_at: m.createdAt,
               }));
 
-              store.setMessages(conversationId, formattedMessages);
+              // 原子性合并本地缓存消息，防止并发 WS 消息丢失
-            } else {
+              store.mergeMessages(conversationId, formattedMessages);
-              store.setMessages(conversationId, []);
             }
           } catch (error) {
             console.warn('[MessageSyncService] 读取本地消息失败:', error);
@@ -224,7 +218,7 @@ export class MessageSyncService implements IMessageSyncService {
 
         // 更新 baseline：合并本地DB后重新计算
         const currentMessages = store.getMessages(conversationId);
-        baselineMaxSeq = currentMessages.reduce((max, m) => Math.max(max, m.seq || 0), 0);
+        const baselineMaxSeq = currentMessages.reduce((max, m) => Math.max(max, m.seq || 0), 0);
 
         // 策略：有本地数据时仅增量同步，无数据时拉快照
         if (baselineMaxSeq > 0) {
@@ -234,9 +228,7 @@ export class MessageSyncService implements IMessageSyncService {
             const newMessages = incrementalResp?.messages || [];
 
             if (newMessages.length > 0) {
-              const existingMsgs = store.getMessages(conversationId);
+              store.mergeMessages(conversationId, newMessages);
-              const mergedMessages = mergeMessagesById(existingMsgs, newMessages);
-              store.setMessages(conversationId, mergedMessages);
 
               messageRepository.saveMessagesBatch(
                 MessageMapper.toCachedMessages(newMessages, conversationId)
@@ -254,7 +246,8 @@ export class MessageSyncService implements IMessageSyncService {
             const snapshotMessages = snapshotResp?.messages || [];
 
             if (snapshotMessages.length > 0) {
-              store.setMessages(conversationId, snapshotMessages);
+              // 快照来自分页接口，后端返回 DESC 顺序；mergeMessages 内部按 seq ASC 排序并合并
+              store.mergeMessages(conversationId, snapshotMessages);
 
               messageRepository.saveMessagesBatch(
                 MessageMapper.toCachedMessages(snapshotMessages, conversationId)
@@ -272,10 +265,7 @@ export class MessageSyncService implements IMessageSyncService {
 
         if (response?.messages && response.messages.length > 0) {
           const newMessages = response.messages;
-          const existingMessages = store.getMessages(conversationId);
+          store.mergeMessages(conversationId, newMessages);
-          const mergedMessages = mergeMessagesById(existingMessages, newMessages);
-
-          store.setMessages(conversationId, mergedMessages);
 
             messageRepository.saveMessagesBatch(
               MessageMapper.toCachedMessages(newMessages, conversationId)
@@ -288,13 +278,22 @@ export class MessageSyncService implements IMessageSyncService {
       console.error('[MessageSyncService] 获取消息失败:', error);
     } finally {
       // 异步填充用户信息（不阻塞消息显示）
+      // 使用 merge 而非覆盖，防止异步期间新到的 WS 消息丢失
       const currentMessages = store.getMessages(conversationId);
       if (currentMessages.length > 0) {
         this.userCacheService.enrichMessagesWithSenderInfo(
           conversationId,
           currentMessages,
           (convId, enrichedMessages) => {
-            store.setMessages(convId, enrichedMessages);
+            const patches = new Map<string, Partial<MessageResponse>>();
+            for (const m of enrichedMessages) {
+              if (m.sender && m.sender_id) {
+                patches.set(String(m.id), { sender: m.sender });
+              }
+            }
+            if (patches.size > 0) {
+              useMessageStore.getState().patchMessages(convId, patches);
+            }
           }
         );
       }
@@ -323,9 +322,7 @@ export class MessageSyncService implements IMessageSyncService {
           created_at: m.createdAt,
         }));
 
-        const existingMessages = store.getMessages(conversationId);
+        store.mergeMessages(conversationId, formattedMessages);
-        const mergedMessages = this.mergeOlderMessages(existingMessages, formattedMessages);
-        store.setMessages(conversationId, mergedMessages);
 
         return formattedMessages;
       }
@@ -340,9 +337,7 @@ export class MessageSyncService implements IMessageSyncService {
           MessageMapper.toCachedMessages(serverMessages, conversationId)
         );
 
-        const existingMessages = store.getMessages(conversationId);
+        store.mergeMessages(conversationId, serverMessages);
-        const mergedMessages = this.mergeOlderMessages(existingMessages, serverMessages);
-        store.setMessages(conversationId, mergedMessages);
 
         return serverMessages;
       }
@@ -612,19 +607,4 @@ export class MessageSyncService implements IMessageSyncService {
     return true;
   }
 
-  private mergeOlderMessages(existing: MessageResponse[], incoming: MessageResponse[]): MessageResponse[] {
-    if (incoming.length === 0) return existing;
-
-    const incomingAsc = [...incoming].sort((a, b) => a.seq - b.seq);
-    if (existing.length === 0) return incomingAsc;
-
-    const existingMinSeq = existing[0]?.seq ?? Number.MAX_SAFE_INTEGER;
-    const incomingMaxSeq = incomingAsc[incomingAsc.length - 1]?.seq ?? Number.MIN_SAFE_INTEGER;
-
-    if (incomingMaxSeq < existingMinSeq) {
-      return [...incomingAsc, ...existing];
-    }
-
-    return mergeMessagesById(existing, incomingAsc);
   }
-}

src/stores/message/services/WSMessageHandler.ts

@@ -25,7 +25,7 @@ import type {
   HandleNewMessageOptions,
 } from '../types';
 import { MAX_FLUSH_ITERATIONS } from '../constants';
-import { useMessageStore, normalizeConversationId, mergeMessagesById } from '../store';
+import { useMessageStore, normalizeConversationId } from '../store';
 
 export class WSMessageHandler implements IWSMessageHandler {
   private deduplication: IMessageDeduplication;
@@ -326,13 +326,9 @@ export class WSMessageHandler implements IWSMessageHandler {
     if (message.type === 'group_message' && sender_id && sender_id !== currentUserId && sender_id !== '10000') {
       this.userCacheService.getSenderInfo(sender_id).then(user => {
         if (user) {
-          const currentMessages = store.getMessages(normalizedConversationId);
+          const patches = new Map<string, Partial<MessageResponse>>();
-          if (currentMessages) {
+          patches.set(String(id), { sender: user });
-            const updatedMessages = currentMessages.map(m =>
+          useMessageStore.getState().patchMessages(normalizedConversationId, patches);
-              m.id === id ? { ...m, sender: user } : m
-            );
-            store.setMessages(normalizedConversationId, updatedMessages);
-          }
         }
       }).catch(error => {
         console.error('[WSMessageHandler] 获取发送者信息失败:', { userId: sender_id, error });
@@ -350,13 +346,11 @@ export class WSMessageHandler implements IWSMessageHandler {
       status: 'normal',
     };
 
-    // 立即更新内存中的消息列表
+    // 立即更新内存中的消息列表 — 使用原子性 mergeMessages 防止并发写入丢失
-    const existingMessages = store.getMessages(normalizedConversationId);
+    const messageExists = useMessageStore.getState().getMessages(normalizedConversationId).some(m => String(m.id) === String(id));
-    const messageExists = existingMessages.some(m => String(m.id) === String(id));
 
     if (!messageExists) {
-      const updatedMessages = mergeMessagesById(existingMessages, [newMessage]);
+      useMessageStore.getState().mergeMessages(normalizedConversationId, [newMessage]);
-      store.setMessages(normalizedConversationId, updatedMessages);
     }
 
     // 更新会话信息
@@ -496,13 +490,12 @@ export class WSMessageHandler implements IWSMessageHandler {
       }
     }
 
-    // 补一条系统消息到当前会话消息流
+    // 补一条系统消息到当前会话消息流（原子性 merge）
     if (message_id && typeof seq === 'number' && seq > 0) {
       const conversationId = this.findConversationIdByGroupId(groupIdStr);
       if (conversationId) {
-        const existingMessages = store.getMessages(conversationId);
+        const messageExists = store.getMessages(conversationId).some(m => String(m.id) === String(message_id));
-        const exists = existingMessages.some(m => String(m.id) === String(message_id));
+        if (!messageExists) {
-        if (!exists) {
           const noticeText = this.buildGroupNoticeText(notice_type, data);
           const systemNoticeMessage: MessageResponse = {
             id: String(message_id),
@@ -517,8 +510,7 @@ export class WSMessageHandler implements IWSMessageHandler {
             created_at: (() => { const d = new Date(timestamp || Date.now()); return Number.isNaN(d.getTime()) ? new Date().toISOString() : d.toISOString(); })(),
           };
 
-          const updatedMessages = [...existingMessages, systemNoticeMessage].sort((a, b) => a.seq - b.seq);
+          useMessageStore.getState().mergeMessages(conversationId, [systemNoticeMessage]);
-          store.setMessages(conversationId, updatedMessages);
         }
       }
     }
@@ -557,26 +549,9 @@ export class WSMessageHandler implements IWSMessageHandler {
   }
 
   private markMessageAsRecalled(conversationId: string, messageId: string): void {
-    const store = useMessageStore.getState();
+    const patches = new Map<string, Partial<MessageResponse>>();
-    const messages = store.getMessages(conversationId);
+    patches.set(String(messageId), { status: 'recalled' as MessageResponse['status'], segments: [] });
-    if (!messages) return;
+    useMessageStore.getState().patchMessages(conversationId, patches);
-
-    let changed = false;
-    const updatedMessages: MessageResponse[] = messages.map((m): MessageResponse => {
-      if (String(m.id) !== String(messageId) || m.status === 'recalled') {
-        return m;
-      }
-      changed = true;
-      return {
-        ...m,
-        status: 'recalled' as MessageResponse['status'],
-        segments: [],
-      };
-    });
-
-    if (!changed) return;
-
-    store.setMessages(conversationId, updatedMessages);
   }
 
   private syncConversationLastMessageOnRecall(conversationId: string, messageId: string): void {

src/stores/message/store.ts

@@ -84,6 +84,8 @@ export interface MessageActions {
   updateConversation: (conversation: ConversationResponse) => void;
   removeConversation: (conversationId: string) => void;
   setMessages: (conversationId: string, messages: MessageResponse[]) => void;
+  mergeMessages: (conversationId: string, incoming: MessageResponse[]) => void;
+  patchMessages: (conversationId: string, patches: Map<string, Partial<MessageResponse>>) => void;
   setUnreadCount: (total: number, system: number) => void;
   setLastSystemMessageAt: (time: string | null) => void;
   setSSEConnected: (connected: boolean) => void;
@@ -331,6 +333,48 @@ export const useMessageStore = create<MessageStore>((set, get) => ({
     });
   },
 
+  /**
+   * 原子性合并消息到 messagesMap
+   * 在 zustand set 回调内完成 read-merge-write，消除并发竞态
+   */
+  mergeMessages: (conversationId: string, incoming: MessageResponse[]) => {
+    if (incoming.length === 0) return;
+    const normalizedId = normalizeConversationId(conversationId);
+    set(state => {
+      const existing = state.messagesMap.get(normalizedId) || [];
+      const merged = mergeMessagesById(existing, incoming);
+      const newMessagesMap = new Map(state.messagesMap);
+      newMessagesMap.set(normalizedId, merged);
+      return { messagesMap: newMessagesMap };
+    });
+  },
+
+  /**
+   * 原子性 patch：按消息 ID 更新指定字段（如 sender、status）
+   * 不影响其他消息，不丢失并发写入
+   */
+  patchMessages: (conversationId: string, patches: Map<string, Partial<MessageResponse>>) => {
+    if (patches.size === 0) return;
+    const normalizedId = normalizeConversationId(conversationId);
+    set(state => {
+      const existing = state.messagesMap.get(normalizedId);
+      if (!existing) return state;
+      let changed = false;
+      const updated = existing.map(m => {
+        const patch = patches.get(String(m.id));
+        if (patch) {
+          changed = true;
+          return { ...m, ...patch };
+        }
+        return m;
+      });
+      if (!changed) return state;
+      const newMessagesMap = new Map(state.messagesMap);
+      newMessagesMap.set(normalizedId, updated);
+      return { messagesMap: newMessagesMap };
+    });
+  },
+
   setUnreadCount: (total: number, system: number) => {
     set({ totalUnreadCount: total, systemUnreadCount: system });
   },