const express = require('express');
const cors = require('cors');
const compression = require('compression');
const path = require('path');
const dotenv = require('dotenv');
const helmet = require('helmet');
const initializeDatabase = require('./config/initDatabase');

// Load environment variables
dotenv.config();

console.log('Current Working Directory:', process.cwd());
console.log('__dirname:', __dirname);

// Import configurations
const config = require('./config');
const { securityHeaders, apiLimiter, validateRequest, corsOptions } = require('./middlewares/security');
const { errorHandler } = require('./middlewares/errorHandler');
const logger = require('./utils/logger');
const monitoring = require('./utils/monitoring');

// Import routes
const authRoutes = require('./routes/auth');
const hospitalRoutes = require('./routes/hospitals');
const userRoutes = require('./routes/users');
const superAdminRoutes = require('./routes/superAdmins');
const documentRoutes = require('./routes/documents');
const pdfRoutes = require('./routes/pdfRoutes');
const onboardingRoutes = require('./routes/onboarding');
const appUserRoutes = require('./routes/appUsers');
const excelDataRoutes = require('./routes/exceldata');
const feedbackRoute = require('./routes/feedbacks');
const analyticsRoute = require('./routes/analysis');

// Import services
const { refreshExpiredTokens } = require('./services/cronJobs');
const { repopulateQueueOnStartup } = require('./controllers/documentsController');
require('./services/webSocket');
require('./services/secondaryWebsocket');

// Create Express app
const app = express();

// Apply security middleware
app.use(helmet());
app.use(securityHeaders);
app.use(compression({
    level: 6,
    threshold: 1024,
    filter: (req, res) => {
        const contentType = res.getHeader('Content-Type');
        return /text|json|javascript|css/.test(contentType);
    }
}));

// Apply rate limiting to all API routes
app.use('/api/', apiLimiter);

// Apply CORS
app.use(cors(corsOptions));

// Request validation
app.use(validateRequest);

// Body parsing middleware
app.use(express.json());
app.use(express.urlencoded({ extended: true }));

// Static files
app.use('/uploads', express.static(path.join(__dirname, '..', 'uploads')));
app.use('/public', express.static(path.join(__dirname, '..', 'public')));

// Request logging middleware
app.use((req, res, next) => {
    const start = Date.now();
    res.on('finish', () => {
        const duration = Date.now() - start;
        monitoring.trackRequest(req.path, req.method, res.statusCode, duration);
        logger.info(`${req.method} ${req.path} ${res.statusCode} - ${duration}ms`);
    });
    next();
});

// Initialize database before starting the server
async function startServer() {
  try {
    // Initialize database
    await initializeDatabase();
    console.log('Database initialized successfully');

    // API routes
    app.use('/api/auth', authRoutes);
    app.use('/api/hospitals', hospitalRoutes);
    app.use('/api/users', userRoutes);
    app.use('/api/superAdmins', superAdminRoutes);
    app.use('/api/onboarding', onboardingRoutes);
    app.use('/api/documents', documentRoutes);
    app.use('/api/pdf', pdfRoutes);
    app.use('/api/app_users', appUserRoutes);
    app.use('/api/process_excel', excelDataRoutes);
    app.use('/api/feedbacks', feedbackRoute);
    app.use('/api/analytics', analyticsRoute);

    // Health check endpoint
    app.get('/health', (req, res) => {
        res.json(monitoring.getHealthStatus());
    });

    // Database sync endpoint (protected by environment check)
    app.post('/api/sync-database', async (req, res) => {
        try {
            // Only allow in development or with proper authentication
            if (process.env.NODE_ENV === 'development' || req.headers['x-sync-token'] === process.env.DB_SYNC_TOKEN) {
                await initializeDatabase();
                res.json({ message: 'Database synchronized successfully' });
            } else {
                res.status(403).json({ error: 'Unauthorized' });
            }
        } catch (error) {
            logger.error('Database sync failed:', error);
            res.status(500).json({ error: 'Database synchronization failed' });
        }
    });

    // Root endpoint
    app.get('/', (req, res) => {
        res.send("SpurrinAI Backend is running!");
    });

    console.log('checking automation!');
    console.log('checking automation!');
    console.log('checking automation!');
    console.log('checking automation!');
    console.log('checking automation!');

    // Error handling middleware
    app.use(errorHandler);

    // Start server
    const PORT = config.server.port;
    const server = app.listen(PORT, () => {
        logger.info(`Server is running on http://localhost:${PORT}`);
        
        // Initialize background tasks
        refreshExpiredTokens();
        // repopulateQueueOnStartup();
    });

    // Graceful shutdown
    const gracefulShutdown = async () => {
        logger.info('Received shutdown signal');
        
        // Close server
        server.close(() => {
            logger.info('HTTP server closed');
        });
        
        // Close database connections
        const db = require('./config/database');
        await db.closePool();
        
        // Close WebSocket connections
        const wss = require('./services/webSocket');
        wss.close(() => {
            logger.info('WebSocket server closed');
        });
        
        process.exit(0);
    };

    process.on('SIGTERM', gracefulShutdown);
    process.on('SIGINT', gracefulShutdown);

    // Handle uncaught exceptions
    process.on('uncaughtException', (error) => {
        logger.error('Uncaught Exception:', error);
        gracefulShutdown();
    });

    // Handle unhandled promise rejections
    process.on('unhandledRejection', (reason, promise) => {
        logger.error('Unhandled Rejection at:', promise, 'reason:', reason);
        gracefulShutdown();
    });

    return server;
  } catch (error) {
    console.error('Failed to start server:', error);
    process.exit(1);
  }
}

startServer();

module.exports = app;