// Error handling middleware for API routes
import { NextApiRequest, NextApiResponse } from 'next';

export function withErrorHandler(handler: (req: NextApiRequest, res: NextApiResponse) => Promise<void>) {
  return async (req: NextApiRequest, res: NextApiResponse) => {
    try {
      await handler(req, res);
    } catch (error: any) {
      console.error('API Error:', error);
      
      // Database connection errors
      if (error.code === 'ECONNREFUSED' || error.code === 'ENOTFOUND') {
        return res.status(503).json({
          success: false,
          error: 'Database connection failed',
          code: 'DB_CONNECTION_ERROR'
        });
      }
      
      // MySQL specific errors
      if (error.code === 'ER_DUP_ENTRY') {
        return res.status(409).json({
          success: false,
          error: 'Duplicate entry',
          code: 'DUPLICATE_ENTRY'
        });
      }
      
      if (error.code === 'ER_NO_REFERENCED_ROW_2') {
        return res.status(400).json({
          success: false,
          error: 'Referenced record not found',
          code: 'FOREIGN_KEY_ERROR'
        });
      }
      
      // Validation errors
      if (error.name === 'ZodError') {
        return res.status(400).json({
          success: false,
          error: 'Validation error',
          details: error.errors,
          code: 'VALIDATION_ERROR'
        });
      }
      
      // JWT errors
      if (error.name === 'JsonWebTokenError') {
        return res.status(401).json({
          success: false,
          error: 'Invalid token',
          code: 'INVALID_TOKEN'
        });
      }
      
      if (error.name === 'TokenExpiredError') {
        return res.status(401).json({
          success: false,
          error: 'Token expired',
          code: 'TOKEN_EXPIRED'
        });
      }
      
      // Generic server error
      return res.status(500).json({
        success: false,
        error: 'Internal server error',
        message: process.env.NODE_ENV === 'development' ? error.message : 'Something went wrong',
        code: 'INTERNAL_ERROR'
      });
    }
  };
}

// CORS middleware
export function withCors(handler: (req: NextApiRequest, res: NextApiResponse) => Promise<void>) {
  return async (req: NextApiRequest, res: NextApiResponse) => {
    // Set CORS headers
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization');
    
    // Handle preflight requests
    if (req.method === 'OPTIONS') {
      return res.status(200).end();
    }
    
    return handler(req, res);
  };
}

// Rate limiting middleware (simple implementation)
const requestCounts = new Map<string, { count: number; resetTime: number }>();

export function withRateLimit(maxRequests: number = 100, windowMs: number = 15 * 60 * 1000) {
  return function(handler: (req: NextApiRequest, res: NextApiResponse) => Promise<void>) {
    return async (req: NextApiRequest, res: NextApiResponse) => {
      const clientId = req.headers['x-forwarded-for'] || req.connection.remoteAddress || 'unknown';
      const now = Date.now();
      
      const clientData = requestCounts.get(clientId as string);
      
      if (!clientData || now > clientData.resetTime) {
        requestCounts.set(clientId as string, {
          count: 1,
          resetTime: now + windowMs
        });
      } else {
        clientData.count++;
        
        if (clientData.count > maxRequests) {
          return res.status(429).json({
            success: false,
            error: 'Too many requests',
            code: 'RATE_LIMIT_EXCEEDED'
          });
        }
      }
      
      return handler(req, res);
    };
  };
}

// Request logging middleware
export function withLogging(handler: (req: NextApiRequest, res: NextApiResponse) => Promise<void>) {
  return async (req: NextApiRequest, res: NextApiResponse) => {
    const start = Date.now();
    
    console.log(`[${new Date().toISOString()}] ${req.method} ${req.url}`);
    
    // Override res.json to log response
    const originalJson = res.json;
    res.json = function(body: any) {
      const duration = Date.now() - start;
      console.log(`[${new Date().toISOString()}] ${req.method} ${req.url} - ${res.statusCode} (${duration}ms)`);
      return originalJson.call(this, body);
    };
    
    return handler(req, res);
  };
}