const logger = require('../utils/logger');

// Error handling middleware
const errorHandler = (err, req, res, next) => {
  let error = { ...err };
  error.message = err.message;

  // Log error
  logger.error('Error occurred:', {
    message: err.message,
    stack: err.stack,
    url: req.url,
    method: req.method,
    ip: req.ip,
    userAgent: req.get('User-Agent')
  });

  // Mongoose bad ObjectId
  if (err.name === 'CastError') {
    const message = 'Resource not found';
    error = { message, statusCode: 404 };
  }

  // Mongoose duplicate key
  if (err.code === 11000) {
    const message = 'Duplicate field value entered';
    error = { message, statusCode: 400 };
  }

  // Mongoose validation error
  if (err.name === 'ValidationError') {
    const message = Object.values(err.errors).map(val => val.message).join(', ');
    error = { message, statusCode: 400 };
  }

  // JWT errors
  if (err.name === 'JsonWebTokenError') {
    const message = 'Invalid token';
    error = { message, statusCode: 401 };
  }

  if (err.name === 'TokenExpiredError') {
    const message = 'Token expired';
    error = { message, statusCode: 401 };
  }

  // MySQL errors
  if (err.code === 'ER_DUP_ENTRY') {
    const message = 'Duplicate entry found';
    error = { message, statusCode: 400 };
  }

  if (err.code === 'ER_NO_REFERENCED_ROW_2') {
    const message = 'Referenced record not found';
    error = { message, statusCode: 400 };
  }

  if (err.code === 'ER_ROW_IS_REFERENCED_2') {
    const message = 'Cannot delete record - it is referenced by other records';
    error = { message, statusCode: 400 };
  }

  // Redis errors
  if (err.code === 'ECONNREFUSED' && err.syscall === 'connect') {
    const message = 'Cache service unavailable';
    error = { message, statusCode: 503 };
  }

  // Network errors
  if (err.code === 'ENOTFOUND') {
    const message = 'Service not found';
    error = { message, statusCode: 503 };
  }

  if (err.code === 'ETIMEDOUT') {
    const message = 'Request timeout';
    error = { message, statusCode: 408 };
  }

  // Default error
  const statusCode = error.statusCode || 500;
  const message = error.message || 'Server Error';

  // Don't leak error details in production
  const response = {
    success: false,
    error: message,
    ...(process.env.NODE_ENV === 'development' && { stack: err.stack })
  };

  res.status(statusCode).json(response);
};

module.exports = errorHandler;