const express = require('express');
const cors = require('cors');
const helmet = require('helmet');
const morgan = require('morgan');
const config = require('./config/environment');
const { pool } = require('./config/database');
const { errorHandler, notFoundHandler } = require('./middleware/errorHandler');
const { ensureAdminExists } = require('./utils/initAdmin');

// Import routes
const participantRoutes = require('./routes/participant.routes');
const adminRoutes = require('./routes/admin.routes');
const lessonRoutes = require('./routes/lesson.routes');

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

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

// CORS configuration
app.use(cors({
  origin: config.corsOrigin,
  credentials: true
}));

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

// Logging middleware
if (config.nodeEnv === 'development') {
  app.use(morgan('dev'));
} else {
  app.use(morgan('combined'));
}

// Health check endpoint
app.get('/health', async (req, res) => {
  try {
    // Check database connection
    await pool.query('SELECT 1');
    res.status(200).json({
      status: 'healthy',
      timestamp: new Date().toISOString(),
      environment: config.nodeEnv,
      database: 'connected'
    });
  } catch (error) {
    res.status(503).json({
      status: 'unhealthy',
      timestamp: new Date().toISOString(),
      environment: config.nodeEnv,
      database: 'disconnected',
      error: error.message
    });
  }
});

// API routes
app.get('/api', (req, res) => {
  res.json({
    message: 'Security Awareness Learning Platform API',
    version: '1.0.0',
    endpoints: {
      participant: '/api/participant',
      admin: '/api/admin',
      lessons: '/api/lessons'
    }
  });
});

// Mount routes
app.use('/api/participant', participantRoutes);
app.use('/api/admin', adminRoutes);
app.use('/api/lesson', lessonRoutes);

// 404 handler
app.use(notFoundHandler);

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

// Initialize and start server
const PORT = config.port;

(async () => {
  try {
    // Ensure admin user exists before starting server
    await ensureAdminExists();

    // Start server
    app.listen(PORT, () => {
      console.log(`
    ========================================
    Security Awareness Learning Platform
    ========================================
    Environment: ${config.nodeEnv}
    Server running on port: ${PORT}
    Database: ${config.database.host}:${config.database.port}/${config.database.name}
    ========================================
      `);
    });
  } catch (error) {
    console.error('Failed to start server:', error);
    process.exit(1);
  }
})();

// Graceful shutdown
process.on('SIGTERM', () => {
  console.log('SIGTERM signal received: closing HTTP server');
  pool.end(() => {
    console.log('Database pool closed');
    process.exit(0);
  });
});

module.exports = app;