import type { ApiErrorBody } from '../schemas/api.js';
import { ERROR_MESSAGES, type ErrorCode } from './codes.js';

/**
 * 前后端共用的 API 错误对象。
 * - 服务端：AllExceptionsFilter 用它把异常序列化成统一错误体；
 * - 前端：请求层把错误体还原成 ApiError，保留 trace_id 便于用户报障。
 */
export class ApiError extends Error {
  readonly code: ErrorCode;
  readonly status: number;
  readonly details?: unknown;
  readonly traceId: string;

  constructor(params: { code: ErrorCode; message?: string; details?: unknown; traceId?: string }) {
    super(params.message ?? ERROR_MESSAGES[params.code]);
    this.name = 'ApiError';
    this.code = params.code;
    this.status = Math.floor(params.code / 100);
    this.details = params.details;
    this.traceId = params.traceId ?? '';
  }

  toBody(): ApiErrorBody {
    return {
      code: this.code,
      message: this.message,
      ...(this.details === undefined ? {} : { details: this.details }),
      trace_id: this.traceId,
    };
  }
}