const { logger } = require('../config/logger');
const { ERROR_CODES, HTTP_STATUS } = require('../config/constants');

// 全局错误处理中间件
const errorHandler = (err, req, res, next) => {
  let error = { ...err };
  error.message = err.message;

  // 记录错误日志
  logger.error('Error occurred:', {
    message: err.message,
    stack: err.stack,
    url: req.originalUrl,
    method: req.method,
    ip: req.ip,
    userAgent: req.get('User-Agent'),
    userId: req.user?.id
  });

  // MySQL错误处理
  if (err.code) {
    switch (err.code) {
      case 'ER_DUP_ENTRY':
        error.message = '数据已存在';
        error.statusCode = HTTP_STATUS.CONFLICT;
        error.errorCode = ERROR_CODES.DUPLICATE_ENTRY;
        break;
      case 'ER_NO_REFERENCED_ROW_2':
        error.message = '关联数据不存在';
        error.statusCode = HTTP_STATUS.BAD_REQUEST;
        error.errorCode = ERROR_CODES.VALIDATION_ERROR;
        break;
      case 'ER_ROW_IS_REFERENCED_2':
        error.message = '数据正在被使用，无法删除';
        error.statusCode = HTTP_STATUS.CONFLICT;
        error.errorCode = ERROR_CODES.VALIDATION_ERROR;
        break;
      case 'ECONNREFUSED':
        error.message = '数据库连接失败';
        error.statusCode = HTTP_STATUS.INTERNAL_SERVER_ERROR;
        error.errorCode = ERROR_CODES.DATABASE_ERROR;
        break;
      default:
        error.message = '数据库操作失败';
        error.statusCode = HTTP_STATUS.INTERNAL_SERVER_ERROR;
        error.errorCode = ERROR_CODES.DATABASE_ERROR;
    }
  }

  // JWT错误处理
  if (err.name === 'JsonWebTokenError') {
    error.message = '无效的访问令牌';
    error.statusCode = HTTP_STATUS.UNAUTHORIZED;
    error.errorCode = ERROR_CODES.AUTHENTICATION_ERROR;
  }

  if (err.name === 'TokenExpiredError') {
    error.message = '访问令牌已过期';
    error.statusCode = HTTP_STATUS.UNAUTHORIZED;
    error.errorCode = ERROR_CODES.AUTHENTICATION_ERROR;
  }

  // 参数验证错误
  if (err.name === 'ValidationError' || err.isJoi) {
    const message = err.details ? err.details.map(detail => detail.message).join(', ') : err.message;
    error.message = `参数验证失败: ${message}`;
    error.statusCode = HTTP_STATUS.BAD_REQUEST;
    error.errorCode = ERROR_CODES.VALIDATION_ERROR;
  }

  // 业务逻辑错误处理
  if (err.message === '余额不足') {
    error.message = '用户积分余额不足，无法完成转账操作。请先为用户充值积分或选择其他用户。';
    error.statusCode = HTTP_STATUS.BAD_REQUEST;
    error.errorCode = ERROR_CODES.VALIDATION_ERROR;
  }

  if (err.message === '用户不存在') {
    error.message = '指定的用户不存在，请检查用户信息后重试。';
    error.statusCode = HTTP_STATUS.BAD_REQUEST;
    error.errorCode = ERROR_CODES.VALIDATION_ERROR;
  }

  // 自定义错误
  if (err.statusCode) {
    error.statusCode = err.statusCode;
    error.errorCode = err.errorCode || ERROR_CODES.INTERNAL_ERROR;
  }

  // 默认错误
  const statusCode = error.statusCode || HTTP_STATUS.INTERNAL_SERVER_ERROR;
  const errorCode = error.errorCode || ERROR_CODES.INTERNAL_ERROR;
  const message = error.message || '服务器内部错误';

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

// 404错误处理
const notFound = (req, res, next) => {
  const error = new Error(`路径 ${req.originalUrl} 未找到`);
  error.statusCode = HTTP_STATUS.NOT_FOUND;
  error.errorCode = ERROR_CODES.NOT_FOUND;
  next(error);
};

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

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

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