const express = require('express');
const cors = require('cors');
const helmet = require('helmet');
const compression = require('compression');
const morgan = require('morgan');
const path = require('path');
require('dotenv').config();

const { sequelize } = require('./config/database');
const logger = require('./utils/logger');
//const rateLimiter = require('./middleware/rateLimiter');
const errorHandler = require('./middleware/errorHandler');

// Import routes
const authRoutes = require('./routes/auth');
const modelRoutes = require('./routes/models');
const chatRoutes = require('./routes/chat');
const documentRoutes = require('./routes/documents');
const feedbackRoutes = require('./routes/feedback');
const toolRoutes = require('./routes/tools');

const app = express();
const PORT = process.env.PORT || 8000;

// Security middleware
app.use(helmet());
app.use(cors({
  origin: process.env.NODE_ENV === 'production' 
    ? ['https://yourdomain.com'] 
    : ['http://localhost:8000'],
  credentials: true
}));

// Compression and logging
app.use(compression());
app.use(morgan('combined', { stream: { write: message => logger.info(message.trim()) } }));

// Body parsing
app.use(express.json({ limit: '50mb' }));
app.use(express.urlencoded({ extended: true, limit: '50mb' }));

// Rate limiting
// app.use(rateLimiter);

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

// API routes
app.use('/api/auth', authRoutes);
app.use('/api/models', modelRoutes);
app.use('/api/chat', chatRoutes);
app.use('/api/documents', documentRoutes);
app.use('/api/feedback', feedbackRoutes);
app.use('/api/tools', toolRoutes);

// Health check
app.get('/api/health', (req, res) => {
  res.json({ 
    status: 'OK', 
    timestamp: new Date().toISOString(),
    version: '1.0.0'
  });
});

// Error handling
app.use(errorHandler);

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

// Database connection and server start
const startServer = async () => {
  try {
    await sequelize.authenticate();
    logger.info('Database connection established successfully');
    
    // Sync database in development
    if (process.env.NODE_ENV === 'development') {
      await sequelize.sync({ alter: true });
      logger.info('Database synchronized');
    }
    
    app.listen(PORT, () => {
      logger.info(`Server running on port ${PORT}`);
      logger.info(`Environment: ${process.env.NODE_ENV}`);
    });
  } catch (error) {
    logger.error('Failed to start server:', error);
    process.exit(1);
  }
};

// Graceful shutdown
process.on('SIGTERM', async () => {
  logger.info('SIGTERM received, shutting down gracefully');
  await sequelize.close();
  process.exit(0);
});

process.on('SIGINT', async () => {
  logger.info('SIGINT received, shutting down gracefully');
  await sequelize.close();
  process.exit(0);
});

startServer();

module.exports = app;