const { getRequestId, logger } = require('../utils/logger');

function expressErrorHandler(err, req, res, next) {
  if (res.headersSent) return next(err);

  const requestedStatus = Number(err?.statusCode || err?.status);
  const status = Number.isInteger(requestedStatus) && requestedStatus >= 400 && requestedStatus <= 599
    ? requestedStatus
    : 500;

  const requestId = getRequestId(req);
  (req.log || logger).error({
    err,
    method: req.method,
    path: req.path || req.originalUrl,
    statusCode: status
  }, 'unhandled request error');

  return res.status(status).json({
    success: false,
    message: status >= 500 ? '服务器内部错误' : (err?.message || '请求处理失败'),
    ...(requestId ? { requestId } : {})
  });
}

module.exports = { expressErrorHandler };