server.js

require('dotenv').config();
const express = require('express');
const cors = require('cors');
const helmet = require('helmet');
const rateLimit = require('express-rate-limit');

// Import services
const database = require('./src/config/database');
const apiRoutes = require('./src/routes/api');
const scheduler = require('./src/services/scheduler');

const app = express();
const PORT = process.env.PORT || 3000;

// Security middleware
app.use(helmet());

// CORS configuration
app.use(cors({
    origin: process.env.NODE_ENV === 'production' ? false : true,
    credentials: true
}));

// Rate limiting
const limiter = rateLimit({
    windowMs: 15 * 60 * 1000, // 15 minutes
    max: 100, // limit each IP to 100 requests per windowMs
    message: 'Too many requests from this IP, please try again later.'
});
app.use(limiter);

// Body parsing middleware
app.use(express.json({ limit: '10mb' }));
app.use(express.urlencoded({ extended: true }));

// Routes
app.use('/api', apiRoutes);

// Health check endpoint
app.get('/health', (req, res) => {
    res.json({
        status: 'OK',
        timestamp: new Date().toISOString(),
        uptime: process.uptime(),
        database: database.isConnected() ? 'Connected' : 'Disconnected'
    });
});

// Root endpoint
app.get('/', (req, res) => {
    res.json({
        message: 'University Email Verifier API',
        version: '1.0.0',
        endpoints: {
            health: '/health',
            stats: '/api/stats',
            verified: '/api/verified',
            generate: '/api/generate',
            verify: '/api/verify/start',
            scheduler: '/api/scheduler/start'
        }
    });
});

// Error handling middleware
app.use((err, req, res, next) => {
    console.error('Error:', err);
    res.status(500).json({
        success: false,
        error: process.env.NODE_ENV === 'production' ? 'Internal server error' : err.message
    });
});

// 404 handler
app.use('*', (req, res) => {
    res.status(404).json({
        success: false,
        error: 'Endpoint not found'
    });
});

// Graceful shutdown
process.on('SIGINT', async () => {
    console.log('\n🛑 Received SIGINT, shutting down gracefully...');
    
    try {
        scheduler.stop();
        await database.disconnect();
        console.log('✅ Shutdown complete');
        process.exit(0);
    } catch (error) {
        console.error('❌ Error during shutdown:', error);
        process.exit(1);
    }
});

process.on('SIGTERM', async () => {
    console.log('\n🛑 Received SIGTERM, shutting down gracefully...');
    
    try {
        scheduler.stop();
        await database.disconnect();
        console.log('✅ Shutdown complete');
        process.exit(0);
    } catch (error) {
        console.error('❌ Error during shutdown:', error);
        process.exit(1);
    }
});

// Start server
async function startServer() {
    try {
        // Connect to database
        await database.connect();
        
        // Start the server
        app.listen(PORT, () => {
            console.log('🚀 University Email Verifier Server Started');
            console.log(`📡 Server running on port ${PORT}`);
            console.log(`🌐 Environment: ${process.env.NODE_ENV || 'development'}`);
            console.log(`📊 Health check: http://localhost:${PORT}/health`);
            console.log(`📋 API docs: http://localhost:${PORT}/`);
            
            // Start scheduler if in production or if explicitly enabled
            if (process.env.NODE_ENV === 'production' || process.env.AUTO_START_SCHEDULER === 'true') {
                console.log('⏰ Starting automated scheduler...');
                scheduler.start();
            } else {
                console.log('⏰ Scheduler not started automatically. Use /api/scheduler/start to start it.');
            }
        });
        
    } catch (error) {
        console.error('❌ Failed to start server:', error);
        process.exit(1);
    }
}

// Start the server
startServer();