/**
 * 统一错误处理中间件
 */

/**
 * 404 错误处理
 */
function notFound(req, res, next) {
  const error = new Error(`Not Found - ${req.originalUrl}`);
  error.statusCode = 404;
  next(error);
}

/**
 * 统一错误响应处理
 */
function errorHandler(err, req, res, next) {
  // 设置状态码
  const statusCode = err.statusCode || 500;

  // 开发环境返回详细错误信息，生产环境返回简化信息
  const isDevelopment = process.env.NODE_ENV === 'development';

  res.status(statusCode).json({
    success: false,
    message: err.message || '服务器内部错误',
    error: isDevelopment ? {
      stack: err.stack,
      ...err
    } : undefined,
    statusCode
  });

  // 记录错误日志
  if (statusCode >= 500) {
    console.error('❌ Server Error:', {
      message: err.message,
      stack: err.stack,
      url: req.originalUrl,
      method: req.method,
      body: req.body,
      query: req.query,
      params: req.params
    });
  }
}

/**
 * 异步错误捕获包装器
 */
function asyncHandler(fn) {
  return (req, res, next) => {
    Promise.resolve(fn(req, res, next)).catch(next);
  };
}

/**
 * 自定义错误类
 */
class AppError extends Error {
  constructor(message, statusCode = 500) {
    super(message);
    this.statusCode = statusCode;
    this.isOperational = true;
    Error.captureStackTrace(this, this.constructor);
  }
}

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