/**
 * Provider 错误分类（实施设计 5：统一映射为六类）。
 *
 * Provider 抛出的错误会被 Core 归一化成这六种之一；界面按 kind 决定提示与是否可重试，
 * 不用话术圆场（实施设计 2.5「失败显式」）。
 */
export const ERROR_KINDS = ['invalid_argument', 'forbidden', 'conflict', 'rate_limited', 'unavailable', 'unknown_result'] as const;

export type ErrorKind = (typeof ERROR_KINDS)[number];

export function isErrorKind(value: unknown): value is ErrorKind {
  return typeof value === 'string' && (ERROR_KINDS as readonly string[]).includes(value);
}

/** Provider 应抛这个错误，而不是裸 Error——裸 Error 会被 Core 归为 unknown_result */
export class ProviderError extends Error {
  readonly kind: ErrorKind;
  readonly detail?: unknown;

  constructor(kind: ErrorKind, message: string, detail?: unknown) {
    super(message);
    this.name = 'ProviderError';
    this.kind = kind;
    if (detail !== undefined) this.detail = detail;
  }
}