import { Request, Response, NextFunction } from 'express';
import { logger } from '../utils/logger.js';
import { ERROR_CODES, HTTP_STATUS } from '@media-manager/shared';

export class AppError extends Error {
  public readonly statusCode: number;
  public readonly code: string;
  public readonly isOperational: boolean;

  constructor(
    message: string,
    statusCode: number = HTTP_STATUS.INTERNAL_SERVER_ERROR,
    code: string = ERROR_CODES.UNKNOWN,
    isOperational: boolean = true
  ) {
    super(message);
    this.statusCode = statusCode;
    this.code = code;
    this.isOperational = isOperational;

    Error.captureStackTrace(this, this.constructor);
  }
}

export function errorHandler(
  err: Error | AppError,
  _req: Request,
  res: Response,
  _next: NextFunction
): void {
  if (err instanceof AppError) {
    logger.warn(`AppError: ${err.message}`, { code: err.code, statusCode: err.statusCode });
    res.status(err.statusCode).json({
      success: false,
      error: {
        code: err.code,
        message: err.message,
      },
    });
    return;
  }

  // 未知错误
  logger.error('Unexpected error:', err);
  res.status(HTTP_STATUS.INTERNAL_SERVER_ERROR).json({
    success: false,
    error: {
      code: ERROR_CODES.UNKNOWN,
      message: process.env.NODE_ENV === 'production' 
        ? 'Internal server error' 
        : err.message,
    },
  });
}

// 异步处理器包装
export function asyncHandler<T>(
  fn: (req: Request, res: Response, next: NextFunction) => Promise<T>
) {
  return (req: Request, res: Response, next: NextFunction) => {
    Promise.resolve(fn(req, res, next)).catch(next);
  };
}