import express from 'express';
import cors from 'cors';
import helmet from 'helmet';
import compression from 'compression';
import rateLimit from 'express-rate-limit';
import dotenv from 'dotenv';
import { PrismaClient } from '@prisma/client';
import { createClient } from 'redis';
import { logger } from './utils/logger';
import { errorHandler } from './middleware/errorHandler';
import { requestLogger } from './middleware/requestLogger';

// Import routes
import authRoutes from './routes/auth';
import docketRoutes from './routes/docket';
import documentRoutes from './routes/documents';
import subscriptionRoutes from './routes/subscriptions';
import healthRoutes from './routes/health';
import notificationRoutes from './routes/notifications';

// Load environment variables
dotenv.config();

const app = express();
const PORT = process.env.PORT || 3001;

// Trust proxy when behind reverse proxy (Caddy)
app.set('trust proxy', true);

// Initialize Prisma client
export const prisma = new PrismaClient({
  log: ['query', 'info', 'warn', 'error'],
});

// Initialize Redis client
export const redis = createClient({
  url: process.env.REDIS_URL || 'redis://localhost:6379',
});

// Connect to Redis
redis.connect().catch((error) => {
  logger.error('Redis connection failed:', error);
});

redis.on('error', (error) => {
  logger.error('Redis error:', error);
});

redis.on('connect', () => {
  logger.info('Connected to Redis');
});

// Security middleware
app.use(helmet({
  crossOriginResourcePolicy: { policy: "cross-origin" }
}));

// CORS configuration
app.use(cors({
  origin: process.env.NODE_ENV === 'production' 
    ? [process.env.FRONTEND_URL, 'http://frontend:806', 'http://localhost:806']
    : ['http://localhost:3000', 'http://localhost:806', 'http://frontend:806', 'http://frontend:3000'],
  credentials: true,
}));

// Rate limiting with proper proxy configuration
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.',
  standardHeaders: true,
  legacyHeaders: false,
  // Skip rate limiting validation errors in production behind proxy
  skip: (req) => {
    // Skip rate limiting if we can't determine the real IP
    return false;
  },
  keyGenerator: (req) => {
    // Use X-Forwarded-For header if available, otherwise fall back to req.ip
    return req.ip || 'unknown';
  },
});

app.use('/api', limiter);

// Stricter rate limiting for auth endpoints
const authLimiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 5, // limit each IP to 5 requests per windowMs
  message: 'Too many authentication attempts, please try again later.',
  standardHeaders: true,
  legacyHeaders: false,
  keyGenerator: (req) => {
    return req.ip || 'unknown';
  },
});

app.use('/api/auth', authLimiter);

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

// Request logging
app.use(requestLogger);

// Routes
app.use('/api/health', healthRoutes);
app.use('/api/auth', authRoutes);
app.use('/api/docket-entries', docketRoutes);
app.use('/api/documents', documentRoutes);
app.use('/api/subscriptions', subscriptionRoutes);
app.use('/api/notifications', notificationRoutes);

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

// Error handling middleware (must be last)
app.use(errorHandler);

// Graceful shutdown
process.on('SIGTERM', async () => {
  logger.info('SIGTERM received, shutting down gracefully');
  
  // Close database connection
  await prisma.$disconnect();
  
  // Close Redis connection
  await redis.quit();
  
  process.exit(0);
});

process.on('SIGINT', async () => {
  logger.info('SIGINT received, shutting down gracefully');
  
  // Close database connection
  await prisma.$disconnect();
  
  // Close Redis connection
  await redis.quit();
  
  process.exit(0);
});

// Start server
app.listen(PORT, () => {
  logger.info(`Server running on port ${PORT}`);
  logger.info(`Environment: ${process.env.NODE_ENV || 'development'}`);
});

export default app;