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

const errorHandler = (err, req, res, next) => {
  // Log error
  logger.error('Error occurred:', {
    message: err.message,
    stack: err.stack,
    path: req.path,
    method: req.method,
    ip: req.ip
  });

  // Sequelize validation errors
  if (err.name === 'SequelizeValidationError') {
    const errors = err.errors.map(e => ({
      field: e.path,
      message: e.message
    }));
    
    return res.status(400).json({
      success: false,
      message: 'Validation error',
      errors
    });
  }

  // Sequelize unique constraint errors
  if (err.name === 'SequelizeUniqueConstraintError') {
    return res.status(409).json({
      success: false,
      message: 'Resource already exists',
      field: err.errors[0]?.path
    });
  }

  // JWT errors
  if (err.name === 'JsonWebTokenError') {
    return res.status(401).json({
      success: false,
      message: 'Invalid token'
    });
  }

  if (err.name === 'TokenExpiredError') {
    return res.status(401).json({
      success: false,
      message: 'Token expired'
    });
  }

  // Multer file upload errors
  if (err.name === 'MulterError') {
    if (err.code === 'LIMIT_FILE_SIZE') {
      return res.status(413).json({
        success: false,
        message: 'File too large'
      });
    }
    return res.status(400).json({
      success: false,
      message: err.message
    });
  }

  // Default error
  const statusCode = err.statusCode || 500;
  const message = err.message || 'Internal server error';

  res.status(statusCode).json({
    success: false,
    message,
    ...(process.env.NODE_ENV === 'development' && { stack: err.stack })
  });
};

module.exports = errorHandler;