import express, { Application, Request, Response, NextFunction } from 'express';
import cors from 'cors';
import helmet from 'helmet';
import rateLimit from 'express-rate-limit';
import dotenv from 'dotenv';
import { PrismaClient } from '@prisma/client';

// Import routes
import authRoutes from './routes/auth';
import clientRoutes from './routes/clients';
import commissionRoutes from './routes/commissions';
import policyRoutes from './routes/policies';
import todoRoutes from './routes/todos';
import documentRoutes from './routes/documents';
import reportRoutes from './routes/reports';
import auditRoutes from './routes/audit';
import notificationRoutes from './routes/notifications';

// Import middleware
import { errorHandler } from './middleware/errorHandler';
import { authMiddleware } from './middleware/auth';
import { auditMiddleware } from './middleware/audit';
import { requestLogger } from './middleware/logger';

// Load environment variables
dotenv.config();

// Initialize Express app
const app: Application = express();
const PORT = process.env.PORT || 3001;

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

// Security middleware
app.use(helmet({
  contentSecurityPolicy: {
    directives: {
      defaultSrc: ["'self'"],
      styleSrc: ["'self'", "'unsafe-inline'"],
      scriptSrc: ["'self'"],
      imgSrc: ["'self'", "data:", "https:"],
    },
  },
  hsts: {
    maxAge: 31536000,
    includeSubDomains: true,
    preload: true,
  },
}));

// CORS configuration
app.use(cors({
  origin: process.env.FRONTEND_URL || 'http://localhost:5173',
  credentials: true,
  methods: ['GET', 'POST', 'PUT', 'PATCH', 'DELETE', 'OPTIONS'],
  allowedHeaders: ['Content-Type', 'Authorization', 'X-Requested-With'],
}));

// Rate limiting
const limiter = rateLimit({
  windowMs: parseInt(process.env.RATE_LIMIT_WINDOW_MS || '900000'),
  max: parseInt(process.env.RATE_LIMIT_MAX_REQUESTS || '100'),
  message: 'Too many requests from this IP, please try again later.',
  standardHeaders: true,
  legacyHeaders: false,
});
app.use(limiter);

// Stricter rate limiting for auth endpoints
const authLimiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 5, // 5 attempts
  message: 'Too many authentication attempts, please try again later.',
});

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

// Request logging
app.use(requestLogger);

// Health check endpoint (no auth required)
app.get('/health', (req: Request, res: Response) => {
  res.status(200).json({
    status: 'healthy',
    timestamp: new Date().toISOString(),
    version: '1.0.0',
    environment: process.env.NODE_ENV,
  });
});

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

// Protected routes (require authentication)
app.use('/api/clients', authMiddleware, auditMiddleware, clientRoutes);
app.use('/api/commissions', authMiddleware, auditMiddleware, commissionRoutes);
app.use('/api/policies', authMiddleware, auditMiddleware, policyRoutes);
app.use('/api/todos', authMiddleware, auditMiddleware, todoRoutes);
app.use('/api/documents', authMiddleware, auditMiddleware, documentRoutes);
app.use('/api/reports', authMiddleware, auditMiddleware, reportRoutes);
app.use('/api/audit', authMiddleware, auditRoutes);
app.use('/api/notifications', authMiddleware, notificationRoutes);

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

// Global error handler
app.use(errorHandler);

// Graceful shutdown
process.on('SIGTERM', async () => {
  console.log('SIGTERM received, shutting down gracefully');
  await prisma.$disconnect();
  process.exit(0);
});

process.on('SIGINT', async () => {
  console.log('SIGINT received, shutting down gracefully');
  await prisma.$disconnect();
  process.exit(0);
});

// Start server
app.listen(PORT, () => {
  console.log(`🚀 InsureCRM Pro Backend Server running on port ${PORT}`);
  console.log(`📊 Environment: ${process.env.NODE_ENV || 'development'}`);
  console.log(`🔒 Security: Helmet enabled, Rate limiting enabled`);
  console.log(`📝 Audit logging: Active`);
});

export default app;