# WebSocket and Server Compatibility Fixes

## Issues Identified and Fixed

### **1. Multiple WebSocket Servers Conflict**
**Problem**: Both AI Chat and Group Chat WebSocket servers were trying to attach to the same HTTP server without proper error handling.

**Fix**: Added proper error handling and graceful initialization:
```javascript
// Initialize WebSocket Servers with proper error handling
let wsServer, groupChatWS;

try {
    console.log('🔌 [WEBSOCKET] Initializing WebSocket servers...');
    
    // Initialize AI Chat WebSocket Server
    wsServer = new WebSocketServer(server);
    console.log('✅ [WEBSOCKET] AI Chat WebSocket server initialized on /ws');
    
    // Initialize Group Chat WebSocket Server
    groupChatWS = new GroupChatWebSocket(server);
    console.log('✅ [WEBSOCKET] Group Chat WebSocket server initialized on /ws/group-chat');
    
} catch (error) {
    console.error('❌ [WEBSOCKET] Failed to initialize WebSocket servers:', error);
    console.error('❌ [WEBSOCKET] Server will continue without WebSocket functionality');
}
```

### **2. Memory Leaks and Connection Management**
**Problem**: WebSocket connections were not properly cleaned up, leading to memory leaks and broken connection references.

**Fix**: Added comprehensive connection management:
- **Periodic Cleanup**: Every 30 seconds, broken connections are removed
- **Statistics Tracking**: Monitor total connections, active connections, messages, and errors
- **Graceful Disconnect**: Proper cleanup when connections close or error

```javascript
setupPeriodicCleanup() {
    // Clean up broken connections every 30 seconds
    setInterval(() => {
        this.cleanupBrokenConnections();
    }, 30000);
    
    // Log statistics every 5 minutes
    setInterval(() => {
        this.logStatistics();
    }, 300000);
}
```

### **3. WebSocket Configuration Conflicts**
**Problem**: Default WebSocket settings could cause conflicts between multiple servers.

**Fix**: Added specific configuration to prevent conflicts:
```javascript
this.wss = new WebSocket.Server({ 
    server,
    path: '/ws/group-chat',
    perMessageDeflate: false, // Disable compression to avoid conflicts
    maxPayload: 16 * 1024 * 1024 // 16MB max payload
});
```

### **4. Error Handling and Recovery**
**Problem**: WebSocket errors could crash the entire server.

**Fix**: Added comprehensive error handling:
- **Connection Errors**: Track and log errors without crashing
- **Authentication Errors**: Graceful handling of invalid tokens
- **Message Errors**: Continue processing other messages if one fails
- **Statistics Tracking**: Monitor error rates for debugging

### **5. Health Check Integration**
**Problem**: No way to monitor WebSocket server status.

**Fix**: Enhanced health check endpoint:
```javascript
// Health check route
app.get('/health', (req, res) => {
    const healthStatus = { 
        status: 'ok',
        mongodb: mongoose.connection.readyState === 1 ? 'connected' : 'disconnected',
        timestamp: new Date().toISOString(),
        websockets: {
            aiChat: wsServer ? {
                status: 'running',
                path: '/ws',
                connections: wsServer.getConnectedClientsCount()
            } : { status: 'not_initialized' },
            groupChat: groupChatWS ? {
                status: 'running',
                path: '/ws/group-chat',
                stats: groupChatWS.getStats()
            } : { status: 'not_initialized' }
        }
    };
    
    res.json(healthStatus);
});
```

## WebSocket Server Features

### **AI Chat WebSocket Server** (`/ws`)
- **Purpose**: AI-powered career and business advice
- **Authentication**: JWT token required
- **Features**: 
  - Real-time AI responses
  - Category auto-detection
  - Content filtering
  - Connection statistics

### **Group Chat WebSocket Server** (`/ws/group-chat`)
- **Purpose**: Real-time group messaging
- **Authentication**: JWT token required
- **Features**:
  - Group-based messaging
  - Typing indicators
  - Message history
  - User presence tracking

## Connection Management

### **Statistics Tracking**
Both servers now track:
- **Total Connections**: Lifetime connection count
- **Active Connections**: Currently connected users
- **Total Messages**: Messages processed
- **Errors**: Connection and processing errors

### **Automatic Cleanup**
- **Broken Connections**: Removed every 30 seconds
- **Empty Groups**: Cleaned up automatically
- **Memory Management**: Prevents memory leaks

### **Graceful Shutdown**
```javascript
process.on('SIGINT', () => {
    console.log('🔄 [WEBSOCKET] Shutting down WebSocket servers...');
    if (wsServer) {
        wsServer.wss.close();
        console.log('✅ [WEBSOCKET] AI Chat WebSocket server closed');
    }
    if (groupChatWS) {
        groupChatWS.wss.close();
        console.log('✅ [WEBSOCKET] Group Chat WebSocket server closed');
    }
    process.exit(0);
});
```

## Testing WebSocket Servers

### **Health Check**
```bash
curl http://135.181.103.182:5500/health
```

**Response:**
```json
{
    "status": "ok",
    "mongodb": "connected",
    "timestamp": "2024-01-15T10:15:00.000Z",
    "websockets": {
        "aiChat": {
            "status": "running",
            "path": "/ws",
            "connections": 5
        },
        "groupChat": {
            "status": "running",
            "path": "/ws/group-chat",
            "stats": {
                "totalConnections": 3,
                "activeGroups": 1,
                "groupStats": {
                    "68d26d2c0af08456538bc0f6": 2
                }
            }
        }
    }
}
```

### **WebSocket Connection Test**
```javascript
// Test AI Chat WebSocket
const ws1 = new WebSocket('ws://135.181.103.182:5500/ws?token=YOUR_JWT_TOKEN');

// Test Group Chat WebSocket
const ws2 = new WebSocket('ws://135.181.103.182:5500/ws/group-chat?token=YOUR_JWT_TOKEN');
```

## Debug Logging

### **Connection Logs**
```
🔌 [WEBSOCKET] Initializing WebSocket servers...
✅ [WEBSOCKET] AI Chat WebSocket server initialized on /ws
✅ [WEBSOCKET] Group Chat WebSocket server initialized on /ws/group-chat
🤖 [WEBSOCKET] AI Chat WebSocket server started on /ws
💬 [WEBSOCKET] Group Chat WebSocket server started on /ws/group-chat
```

### **Statistics Logs**
```
📊 [WEBSOCKET STATS] AI Chat: {
    totalConnections: 25,
    activeConnections: 8,
    currentClients: 8,
    totalMessages: 156,
    errors: 2
}

📊 [WEBSOCKET STATS] Group Chat: {
    totalConnections: 15,
    activeConnections: 5,
    activeGroups: 2,
    totalMessages: 89,
    errors: 1
}
```

### **Cleanup Logs**
```
🧹 [WEBSOCKET] Cleaned up 3 broken connections
🧹 [WEBSOCKET] Cleaned up 2 broken AI Chat connections
```

## Benefits

✅ **Stable Operation**: Both WebSocket servers can run simultaneously  
✅ **Memory Management**: Automatic cleanup prevents memory leaks  
✅ **Error Recovery**: Graceful handling of connection issues  
✅ **Monitoring**: Comprehensive health checks and statistics  
✅ **Scalability**: Proper connection management for high loads  
✅ **Debugging**: Detailed logging for troubleshooting  

## Server Startup

The server now starts with proper WebSocket initialization:

```bash
node server.js
```

**Expected Output:**
```
🔌 [WEBSOCKET] Initializing WebSocket servers...
✅ [WEBSOCKET] AI Chat WebSocket server initialized on /ws
✅ [WEBSOCKET] Group Chat WebSocket server initialized on /ws/group-chat
🤖 [WEBSOCKET] AI Chat WebSocket server started on /ws
💬 [WEBSOCKET] Group Chat WebSocket server started on /ws/group-chat
✅ Database connection established
🚀 Server running on http://localhost:5500
📝 Environment: development
```

Both WebSocket servers and the HTTP server now work together seamlessly! 🎉
