fix(websocket): use singleton socket to prevent disconnection on re-render

packages/web-client/src/features/chat/presentation/hooks/useChat.ts

@@ -2,6 +2,10 @@ import { useCallback, useEffect, useRef } from 'react';
 import { io, Socket } from 'socket.io-client';
 import { useChatStore, Message } from '../stores/chatStore';
 
+// Singleton socket instance to prevent multiple connections
+let globalSocket: Socket | null = null;
+let currentUserId: string | null = null;
+
 export function useChat() {
   const socketRef = useRef<Socket | null>(null);
   const {
@@ -16,14 +20,32 @@ export function useChat() {
     setConnected,
   } = useChatStore();
 
-  // Initialize WebSocket connection
+  // Initialize WebSocket connection (singleton pattern)
   useEffect(() => {
     if (!userId) return;
 
+    // If socket exists for same user, reuse it
+    if (globalSocket && currentUserId === userId && globalSocket.connected) {
+      socketRef.current = globalSocket;
+      setConnected(true);
+      return;
+    }
+
+    // If socket exists for different user or disconnected, clean up
+    if (globalSocket) {
+      globalSocket.disconnect();
+      globalSocket = null;
+    }
+
+    currentUserId = userId;
+
     const socket = io('/ws/conversation', {
       path: '/ws/conversation/socket.io',
       query: { userId },
       transports: ['websocket'],
+      reconnection: true,
+      reconnectionAttempts: 5,
+      reconnectionDelay: 1000,
     });
 
     socket.on('connect', () => {
@@ -77,7 +99,6 @@ export function useChat() {
 
     socket.on('tool_result', (data) => {
       console.log('Tool result:', data);
-      // Could update message with tool result
     });
 
     socket.on('error', (error) => {
@@ -85,11 +106,10 @@ export function useChat() {
       setStreaming(false);
     });
 
+    globalSocket = socket;
     socketRef.current = socket;
 
-    return () => {
+    // Don't disconnect on cleanup - keep singleton alive
-      socket.disconnect();
-    };
   }, [userId]);
 
   // Send message
@@ -114,15 +134,16 @@ export function useChat() {
       };
       addMessage(conversationId, userMessage);
 
-      // Send via WebSocket
+      // Send via WebSocket (use globalSocket for reliability)
-      if (socketRef.current?.connected) {
+      const socket = globalSocket || socketRef.current;
+      if (socket?.connected) {
         console.log('Sending message via WebSocket:', { conversationId, content: content.trim() });
-        socketRef.current.emit('message', {
+        socket.emit('message', {
           conversationId,
           content: content.trim(),
         });
       } else {
-        console.error('WebSocket not connected, cannot send message');
+        console.error('WebSocket not connected, cannot send message. Socket state:', socket?.connected);
       }
     },
     [userId, currentConversationId, addMessage],