class AppError extends Error {
  constructor(message, statusCode) {
    super(message);
    this.statusCode = statusCode;
    this.isOperational = true;
    Error.captureStackTrace(this, this.constructor);
  }
}

function errorHandler(err, _req, res, _next) {
  const statusCode = err.isOperational ? err.statusCode : 500;
  const message = err.isOperational ? err.message : 'Internal server error';

  console.error(`[ERROR] ${statusCode} - ${err.message}`);
  if (!err.isOperational) console.error(err.stack);

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

function asyncHandler(fn) {
  return (req, res, next) => Promise.resolve(fn(req, res, next)).catch(next);
}

module.exports = { AppError, errorHandler, asyncHandler };