const express = require('express');
const { createServer } = require('http');
const { Server } = require('socket.io');
const cors = require('cors');
const helmet = require('helmet');
const compression = require('compression');
const dotenv = require('dotenv');
const path = require('path');
const fs = require('fs').promises;

// Load environment variables
dotenv.config();

class TikVibeServer {
  constructor() {
    this.app = express();
    this.httpServer = createServer(this.app);
    
    // Setup Socket.IO for real-time features
    this.io = new Server(this.httpServer, {
      cors: {
        origin: '*',
        credentials: true,
        methods: ['GET', 'POST']
      },
      maxHttpBufferSize: 1e8 // 100MB for video streaming
    });

    this.PORT = process.env.PORT || 7860;
    this.connectedUsers = new Map();
    this.projectRooms = new Map();
    this.activeRenders = new Map();
  }

  async initialize() {
    console.log('🚀 Initializing TikVibe Backend Server...');
    
    // Create required directories
    await this.createDirectories();
    
    this.setupMiddleware();
    this.setupRoutes();
    this.setupWebSocket();
    this.setupErrorHandling();
    this.setupCleanupJobs();

    console.log('✅ Server initialization complete');
  }

  async createDirectories() {
    const dirs = ['uploads', 'renders', 'temp'];
    for (const dir of dirs) {
      const dirPath = path.join(__dirname, '..', dir);
      await fs.mkdir(dirPath, { recursive: true });
      console.log(`✅ Directory ready: ${dir}`);
    }
  }

  setupMiddleware() {
    // Security middleware
    this.app.use(helmet({
      contentSecurityPolicy: false,
      crossOriginEmbedderPolicy: false,
      crossOriginResourcePolicy: { policy: "cross-origin" }
    }));
    
    // CORS configuration
    this.app.use(cors({
      origin: '*',
      credentials: true,
      methods: ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS'],
      allowedHeaders: ['Content-Type', 'Authorization', 'X-Requested-With']
    }));
    
    // Compression for faster responses
    this.app.use(compression({
      level: 6,
      threshold: 1024,
      filter: (req, res) => {
        if (req.headers['x-no-compression']) return false;
        return compression.filter(req, res);
      }
    }));
    
    // Body parsing with increased limits for video
    this.app.use(express.json({ limit: '500mb' }));
    this.app.use(express.urlencoded({ extended: true, limit: '500mb' }));
    
    // Static file serving
    this.app.use('/uploads', express.static('uploads'));
    this.app.use('/renders', express.static('renders'));
    
    // Request logging with timing
    this.app.use((req, res, next) => {
      req.startTime = Date.now();
      console.log(`📥 ${new Date().toISOString()} - ${req.method} ${req.path}`);
      
      res.on('finish', () => {
        const duration = Date.now() - req.startTime;
        console.log(`📤 ${req.method} ${req.path} - ${res.statusCode} - ${duration}ms`);
      });
      
      next();
    });
  }

  setupRoutes() {
    // Health check with system info
    this.app.get('/health', (req, res) => {
      res.json({
        status: 'healthy',
        timestamp: new Date().toISOString(),
        uptime: process.uptime(),
        environment: process.env.NODE_ENV || 'production',
        server: 'TikVibe Backend',
        version: '2.0.0',
        system: {
          memory: process.memoryUsage(),
          cpu: process.cpuUsage(),
          node: process.version,
          platform: process.platform
        }
      });
    });

    // Root endpoint with full API documentation
    this.app.get('/', (req, res) => {
      res.json({
        name: '🎥 TikVibe Creator Pro API',
        version: '2.0.0',
        description: 'Advanced AI-Powered Video Editing Platform',
        documentation: '/api/docs',
        endpoints: {
          health: {
            path: '/health',
            method: 'GET',
            description: 'System health check'
          },
          test: {
            path: '/api/test',
            method: 'GET',
            description: 'Test API connection'
          },
          ai: {
            velocity: {
              path: '/api/ai/velocity-edit',
              method: 'POST',
              description: 'Create velocity/fancam style edit with beat sync'
            },
            beatMontage: {
              path: '/api/ai/beat-montage',
              method: 'POST',
              description: 'Create beat-synced montage with perfect timing'
            },
            aesthetic: {
              path: '/api/ai/aesthetic-edit',
              method: 'POST',
              description: 'Apply aesthetic filters and color grading'
            },
            smooth: {
              path: '/api/ai/smooth-transitions',
              method: 'POST',
              description: 'Create smooth transitions between clips'
            },
            vlog: {
              path: '/api/ai/vlog-edit',
              method: 'POST',
              description: 'Create vlog-style edit with text overlays'
            },
            imitate: {
              path: '/api/ai/imitate-style',
              method: 'POST',
              description: 'Imitate editing style from inspiration video'
            }
          },
          analytics: {
            trends: '/api/trends',
            predict: '/api/ai/predict-trends'
          },
          auth: {
            login: '/api/auth/login',
            register: '/api/auth/register'
          }
        }
      });
    });

    // API Documentation
    this.app.get('/api/docs', (req, res) => {
      res.send(`
        <!DOCTYPE html>
        <html>
        <head>
          <title>TikVibe API Documentation</title>
          <style>
            body { font-family: Arial; background: #0a0a0a; color: white; padding: 20px; }
            h1 { color: #ff0050; }
            h2 { color: #00f2ea; }
            .endpoint { background: #1a1a1a; padding: 15px; margin: 10px 0; border-radius: 5px; }
            .method { color: #00ff00; font-weight: bold; }
            .path { color: #ff0050; }
            pre { background: #2a2a2a; padding: 10px; border-radius: 3px; }
          </style>
        </head>
        <body>
          <h1>🎥 TikVibe Creator Pro API</h1>
          <p>Base URL: https://andevs-realeditz.hf.space</p>
          
          <h2>AI Editing Endpoints</h2>
          
          <div class="endpoint">
            <span class="method">POST</span> <span class="path">/api/ai/velocity-edit</span>
            <p>Create velocity/fancam style edit with beat sync</p>
            <pre>FormData: {
  clips: File[] (video files),
  audio: File (music file),
  intensity: "low" | "medium" | "high"
}</pre>
          </div>

          <div class="endpoint">
            <span class="method">POST</span> <span class="path">/api/ai/beat-montage</span>
            <p>Create beat-synced montage</p>
            <pre>FormData: {
  clips: File[] (video files),
  audio: File (music file),
  montageType: "fancam" | "cinematic"
}</pre>
          </div>

          <div class="endpoint">
            <span class="method">POST</span> <span class="path">/api/ai/aesthetic-edit</span>
            <p>Apply aesthetic filters</p>
            <pre>FormData: {
  clips: File[] (video files),
  audio: File (optional),
  aesthetic: "vintage" | "cinematic" | "vibrant" | "moody" | "dreamy"
}</pre>
          </div>

          <div class="endpoint">
            <span class="method">POST</span> <span class="path">/api/ai/smooth-transitions</span>
            <p>Create smooth transitions</p>
            <pre>FormData: {
  clips: File[] (video files),
  audio: File (optional)
}</pre>
          </div>

          <div class="endpoint">
            <span class="method">POST</span> <span class="path">/api/ai/vlog-edit</span>
            <p>Create vlog-style edit</p>
            <pre>FormData: {
  clips: File[] (video files),
  audio: File (optional)
}</pre>
          </div>

          <div class="endpoint">
            <span class="method">POST</span> <span class="path">/api/ai/imitate-style</span>
            <p>Imitate style from inspiration video</p>
            <pre>FormData: {
  inspoVideo: File (inspiration video),
  clips: File[] (your clips),
  audio: File (optional)
}</pre>
          </div>
        </body>
        </html>
      `);
    });

    // Test endpoint
    this.app.get('/api/test', (req, res) => {
      res.json({
        success: true,
        message: '✅ TikVibe API is working correctly!',
        timestamp: new Date().toISOString(),
        features: [
          'velocity-edit',
          'beat-montage',
          'aesthetic-edit',
          'smooth-transitions',
          'vlog-edit',
          'imitate-style'
        ]
      });
    });

    // Auth endpoints (simplified)
    this.app.post('/api/auth/login', (req, res) => {
      const { email, password } = req.body;
      
      if (!email || !password) {
        return res.status(400).json({
          success: false,
          message: 'Email and password required'
        });
      }

      res.json({
        success: true,
        message: 'Login successful',
        token: 'mock-jwt-token-' + Date.now(),
        user: {
          id: 1,
          email: email,
          name: email.split('@')[0]
        }
      });
    });

    this.app.post('/api/auth/register', (req, res) => {
      const { email, password, name } = req.body;
      
      if (!email || !password) {
        return res.status(400).json({
          success: false,
          message: 'Email and password required'
        });
      }

      res.json({
        success: true,
        message: 'Registration successful',
        user: {
          id: Date.now(),
          email: email,
          name: name || email.split('@')[0]
        }
      });
    });

    // Trends endpoint with mock data
    this.app.get('/api/trends', (req, res) => {
      const { category = 'all', timeframe = '24h' } = req.query;
      
      const trends = {
        all: [
          { id: 1, name: '#dancechallenge', category: 'hashtag', growth: 25, views: 1000000 },
          { id: 2, name: 'Summer Vibes', category: 'sound', growth: 15, views: 500000 },
          { id: 3, name: 'Glitch Effect', category: 'effect', growth: -5, views: 250000 }
        ]
      };

      res.json({
        success: true,
        timeframe,
        category,
        trends: trends[category] || trends.all
      });
    });

    // AI Routes
    const aiRouter = require('./routes/ai');
    this.app.use('/api/ai', aiRouter);

    // ============= VIDEO DOWNLOAD ENDPOINT =============
    this.app.get('/api/video/download/:filename', async (req, res) => {
      try {
        const filename = req.params.filename;
        // Sanitize filename to prevent path traversal
        const safeFilename = path.basename(filename);
        const filepath = path.join(__dirname, '../renders', safeFilename);
        
        console.log('📥 Download requested:', safeFilename);
        console.log('Full path:', filepath);
        
        // Check if file exists
        try {
          await fs.access(filepath);
        } catch (error) {
          console.error('File not found:', filepath);
          return res.status(404).json({ 
            error: 'File not found',
            message: 'The video file may have been deleted or expired'
          });
        }
        
        // Get file stats
        const stats = await fs.stat(filepath);
        console.log(`File size: ${stats.size} bytes`);
        
        // Set headers
        res.setHeader('Content-Disposition', `attachment; filename="${safeFilename}"`);
        res.setHeader('Content-Type', 'video/mp4');
        res.setHeader('Content-Length', stats.size);
        
        // Send file
        res.sendFile(filepath, (err) => {
          if (err) {
            console.error('Error sending file:', err);
            if (!res.headersSent) {
              res.status(500).json({ error: 'Failed to send file' });
            }
          } else {
            console.log('✅ File sent successfully:', safeFilename);
          }
        });
        
      } catch (error) {
        console.error('Download error:', error);
        res.status(500).json({ 
          error: 'Download failed',
          message: error.message 
        });
      }
    });

    // Progress tracking for renders
    this.app.get('/api/render/progress/:renderId', (req, res) => {
      const { renderId } = req.params;
      const progress = this.activeRenders.get(renderId) || 0;
      res.json({ renderId, progress });
    });

    // Catch-all for undefined routes
    this.app.use('*', (req, res) => {
      res.status(404).json({
        success: false,
        message: 'Endpoint not found',
        path: req.originalUrl,
        availableEndpoints: '/api/docs'
      });
    });
  }

  setupWebSocket() {
    this.io.on('connection', (socket) => {
      console.log('🔌 Client connected:', socket.id);

      socket.emit('connected', { 
        id: socket.id,
        message: 'Connected to TikVibe server',
        timestamp: new Date().toISOString()
      });

      this.connectedUsers.set(socket.id, {
        id: socket.id,
        joinedAt: new Date().toISOString(),
        lastActivity: new Date().toISOString()
      });

      socket.on('project:join', (data) => {
        const { projectId, userId, userName } = data;
        socket.join(`project:${projectId}`);
        
        if (!this.projectRooms.has(projectId)) {
          this.projectRooms.set(projectId, new Set());
        }
        this.projectRooms.get(projectId).add(socket.id);
        
        socket.emit('project:joined', {
          projectId,
          users: Array.from(this.projectRooms.get(projectId)).length
        });
        
        socket.to(`project:${projectId}`).emit('user:joined', {
          userId: userId || socket.id,
          userName: userName || 'Anonymous',
          timestamp: new Date().toISOString()
        });

        console.log(`👤 User ${userName || socket.id} joined project ${projectId}`);
      });

      socket.on('project:message', (data) => {
        const { projectId, message, userId, userName } = data;
        
        const messageData = {
          id: Date.now(),
          userId: userId || socket.id,
          userName: userName || 'Anonymous',
          message: message,
          timestamp: new Date().toISOString()
        };
        
        socket.emit('message:sent', messageData);
        socket.to(`project:${projectId}`).emit('project:message', messageData);
      });

      socket.on('disconnect', () => {
        console.log('🔌 Client disconnected:', socket.id);
        this.connectedUsers.delete(socket.id);
        
        this.projectRooms.forEach((users, projectId) => {
          if (users.has(socket.id)) {
            users.delete(socket.id);
            socket.to(`project:${projectId}`).emit('user:left', {
              userId: socket.id,
              timestamp: new Date().toISOString()
            });
            
            if (users.size === 0) {
              this.projectRooms.delete(projectId);
            }
          }
        });
      });
    });
  }

  setupErrorHandling() {
    this.app.use((err, req, res, next) => {
      console.error('❌ Global error:', err);
      
      const status = err.status || 500;
      const message = err.message || 'Internal server error';
      
      console.error({
        timestamp: new Date().toISOString(),
        path: req.path,
        method: req.method,
        status,
        message,
        stack: err.stack
      });
      
      res.status(status).json({
        success: false,
        error: message,
        code: err.code,
        timestamp: new Date().toISOString()
      });
    });
  }

  setupCleanupJobs() {
    // Clean up old files every hour
    setInterval(async () => {
      try {
        const now = Date.now();
        const dirs = ['uploads', 'renders', 'temp'];
        
        for (const dir of dirs) {
          const dirPath = path.join(__dirname, '..', dir);
          const files = await fs.readdir(dirPath);
          
          for (const file of files) {
            const filePath = path.join(dirPath, file);
            const stats = await fs.stat(filePath);
            
            // Delete files older than 1 hour (uploads/temp) or 24 hours (renders)
            const maxAge = dir === 'renders' ? 86400000 : 3600000; // 24 hours or 1 hour
            if (now - stats.mtimeMs > maxAge) {
              await fs.unlink(filePath);
              console.log(`🧹 Cleaned up old file: ${dir}/${file}`);
            }
          }
        }
      } catch (error) {
        console.error('Cleanup error:', error);
      }
    }, 3600000); // Every hour
  }

  async start() {
    await this.initialize();
    
    this.httpServer.listen(this.PORT, '0.0.0.0', () => {
      console.log(`
╔══════════════════════════════════════════════════════════╗
║                                                          ║
║   🎥 TikVibe Creator Pro Backend                        ║
║   ==================================================   ║
║                                                          ║
║   🚀 Server: https://andevs-realeditz.hf.space          ║
║   🔌 WebSocket: wss://andevs-realeditz.hf.space         ║
║   🌐 Environment: ${process.env.NODE_ENV || 'production'}                ║
║   📊 Status: ONLINE                                       ║
║                                                          ║
║   📡 AI Endpoints:                                        ║
║      • ⚡ /api/ai/velocity-edit                          ║
║      • 🎵 /api/ai/beat-montage                           ║
║      • 🎨 /api/ai/aesthetic-edit                         ║
║      • 🔄 /api/ai/smooth-transitions                     ║
║      • 🎥 /api/ai/vlog-edit                              ║
║      • 🎭 /api/ai/imitate-style                          ║
║                                                          ║
║   📥 Download: /api/video/download/:filename             ║
║   📚 Documentation: /api/docs                            ║
║   💚 Health Check: /health                               ║
║                                                          ║
╚══════════════════════════════════════════════════════════╝
      `);
    });
  }

  async shutdown() {
    console.log('\n🛑 Shutting down gracefully...');
    
    this.io.emit('server:shutdown', {
      message: 'Server is shutting down',
      timestamp: new Date().toISOString()
    });
    
    this.io.close(() => {
      console.log('✅ Socket.IO closed');
    });
    
    this.httpServer.close(() => {
      console.log('✅ HTTP server closed');
      process.exit(0);
    });
    
    setTimeout(() => {
      console.error('❌ Force shutdown after timeout');
      process.exit(1);
    }, 10000);
  }
}

const server = new TikVibeServer();

process.on('SIGTERM', () => server.shutdown());
process.on('SIGINT', () => server.shutdown());
process.on('uncaughtException', (err) => {
  console.error('❌ Uncaught Exception:', err);
  server.shutdown();
});
process.on('unhandledRejection', (err) => {
  console.error('❌ Unhandled Rejection:', err);
  server.shutdown();
});

server.start().catch(err => {
  console.error('❌ Failed to start server:', err);
  process.exit(1);
});