const { logError } = require('./logger');

/**
 * Creates a user-friendly error message from an error object
 * @param {Error} err - Error object
 * @returns {string} - User-friendly error message
 */
function getUserFriendlyError(err) {
  if (!err) {
    return 'An unknown error occurred';
  }

  // Handle specific error types
  if (err.code === 'EADDRINUSE') {
    return 'The requested port is already in use. Please choose a different port.';
  }
  
  if (err.code === 'ENOENT') {
    return 'The requested file or directory was not found.';
  }
  
  if (err.code === 'EACCES') {
    return 'Permission denied. Please ensure you have the necessary permissions.';
  }
  
  if (err.code === 'ECONNREFUSED') {
    return 'Connection refused. The service may not be running.';
  }
  
  if (err.code === 'ETIMEDOUT') {
    return 'Operation timed out. Please try again.';
  }
  
  // Check for validation errors
  if (err.message && err.message.includes('validation') || err.message.includes('Invalid')) {
    return err.message;
  }
  
  // Generic error message
  if (err.message) {
    // Don't expose internal error details in production
    if (process.env.NODE_ENV === 'production') {
      return 'An error occurred processing your request. Please try again.';
    }
    return err.message;
  }
  
  return 'An unexpected error occurred. Please try again.';
}

/**
 * Creates an error response object
 * @param {Error} err - Error object
 * @param {number} defaultStatusCode - Default HTTP status code
 * @returns {object} - Error response object
 */
function createErrorResponse(err, defaultStatusCode = 500) {
  const message = getUserFriendlyError(err);
  const statusCode = err.statusCode || err.status || defaultStatusCode;
  
  logError('ErrorHandler', `Error: ${err.message || err} (Status: ${statusCode})`);
  
  return {
    statusCode,
    headers: {
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      error: err.name || 'Error',
      message: message,
      ...(process.env.NODE_ENV !== 'production' && err.stack ? { stack: err.stack } : {})
    })
  };
}

module.exports = { getUserFriendlyError, createErrorResponse };