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

const logger = require('./config/logger');
const pool = require('./config/database');
const apiRoutes = require('./routes/api');
const { authenticateApiKey } = require('./middleware/auth');
const createRateLimiter = require('./middleware/rateLimiter');
const { ensureRealtimeSchema } = require('./services/realtimeSchema');
const { attachRealtimeServer, closeRealtimeServer } = require('./services/realtimeService');
const { ensureBootstrapAdmin } = require('./utils/bootstrapAdmin');
const { startAlertScheduler } = require('./services/alertSchedulerService');
const { startTelegramImporter } = require('./services/telegramImportService');

const app = express();
const PORT = process.env.PORT || 3000;
let server;
let stopAlertScheduler = () => {};
let stopTelegramImporter = () => Promise.resolve();

// Security middleware
app.use(helmet({
    crossOriginResourcePolicy: false,
}));
app.use(cors({
  origin: process.env.CORS_ORIGIN || '*',
  credentials: true
}));

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

// Compression
app.use(compression());

// Static files for avatars
const path = require('path');
app.use('/uploads', express.static(path.join(__dirname, '../public/uploads')));

// Logging middleware
app.use((req, res, next) => {
  logger.info(`${req.method} ${req.path}`, {
    ip: req.ip,
    userAgent: req.get('user-agent')
  });
  next();
});

// Health check (no auth required)
app.get('/health', (req, res) => {
  res.json({ 
    status: 'healthy',
    timestamp: new Date().toISOString(),
    version: '1.0.0'
  });
});

// Auth routes (no API key required)
const authRouter = require('./routes/auth');
app.use('/api/v1/auth', 
  createRateLimiter(100, 3600000), // 100 requests per hour for auth
  authRouter
);

// Upload routes (JWT auth required, no API key) - TEMPORARILY DISABLED
// Uncomment after installing multer: npm install multer
try {
  const uploadRouter = require('./routes/upload');
  app.use('/api/v1/upload',
    createRateLimiter(50, 3600000), // 50 uploads per hour
    uploadRouter
  );
  logger.info('Upload routes enabled');
} catch (error) {
  logger.warn('Upload routes disabled - multer not installed. Run: npm install multer');
}

// Passenger telemetry has its own Firebase ID-token authentication inside apiRoutes.
// All other API routes keep the existing API-key/custom-JWT contract.
app.use('/api/v1', 
  (req, res, next) => {
    if (req.path === '/passenger-telemetry/ingest') {
      return next();
    }
    return authenticateApiKey(req, res, next);
  },
  createRateLimiter(1000, 3600000), // 1000 requests per hour
  apiRoutes
);

// 404 handler
app.use((req, res) => {
  res.status(404).json({ 
    error: 'Not Found',
    message: `Route ${req.method} ${req.path} not found`
  });
});

// Global error handler
app.use((err, req, res, next) => {
  logger.error('Unhandled error:', err);
  
  // Multer errors
  if (err.code === 'LIMIT_FILE_SIZE') {
    return res.status(400).json({ 
      error: 'Размер файла не должен превышать 5 МБ.'
    });
  }
  
  if (err.message && (err.message.includes('Only image files are allowed') || err.message.includes('Only JPEG, PNG, and WEBP images are allowed'))) {
    return res.status(400).json({ 
      error: 'Поддерживаются только изображения JPG, PNG и WEBP.'
    });
  }
  
  res.status(500).json({ 
    error: 'Internal Server Error',
    message: process.env.NODE_ENV === 'development' ? err.message : 'Something went wrong'
  });
});

// Graceful shutdown
function shutdown(signal) {
  logger.info('SIGTERM signal received: closing HTTP server');
  logger.info(`${signal} signal received: closing HTTP server`);

  closeRealtimeServer();
  stopAlertScheduler();
  stopTelegramImporter().catch(() => {});

  if (!server) {
    process.exit(0);
  }

  server.close(() => {
    logger.info('HTTP server closed');
    process.exit(0);
  });
}

process.on('SIGTERM', () => shutdown('SIGTERM'));
process.on('SIGINT', () => shutdown('SIGINT'));

function sleep(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

async function waitForDatabase({ attempts = 30, delayMs = 1000 } = {}) {
  for (let attempt = 1; attempt <= attempts; attempt += 1) {
    try {
      await pool.query('SELECT 1');
      return;
    } catch (error) {
      if (attempt === attempts) {
        throw error;
      }

      logger.warn(`Database is not ready yet (${attempt}/${attempts}); retrying...`);
      await sleep(delayMs);
    }
  }
}

async function startServer() {
  try {
    await waitForDatabase();
    await ensureRealtimeSchema();
    await ensureBootstrapAdmin();
    stopAlertScheduler = startAlertScheduler();
    stopTelegramImporter = startTelegramImporter();

    server = app.listen(PORT, () => {
      logger.info(`Server is running on port ${PORT}`);
      logger.info(`Environment: ${process.env.NODE_ENV || 'development'}`);
      logger.info(`API Base: http://localhost:${PORT}/api/v1`);
    });

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

startServer();

module.exports = app;