错误码与 HTTP 状态

const API_BASE = 'https://api.payhub.example';

// 返回"下一步怎么做"；未知错误码按 HTTP 状态处理
export async function callPayHub(method, path, { body, idempotencyKey } = {}) {
  let res;
  try {
    res = await fetch(`${API_BASE}${path}`, {
      method,
      headers: {
        Authorization: `Bearer ${process.env.PAYHUB_API_KEY}`,
        ...(body ? { 'Content-Type': 'application/json' } : {}),
        ...(idempotencyKey ? { 'Idempotency-Key': idempotencyKey } : {})
      },
      body: body ? JSON.stringify(body) : undefined,
      signal: AbortSignal.timeout(20_000)
    });
  } catch (cause) {
    return { next: 'unknown', cause }; // 超时或网络错误：结果未知，同键重试或按业务号查询
  }
  const data = await res.json().catch(() => null); // 5xx 可能不是 JSON
  const requestId = data?.request_id;
  if (res.ok) return { next: 'check_status', httpStatus: res.status, data, requestId };
  if (res.status === 429) {
    const raw = res.headers.get('Retry-After');
    const after = raw === null ? NaN : Number(raw);
    return { next: 'retry_same_key', afterSeconds: Number.isFinite(after) ? after : 1, requestId };
  }
  if (res.status >= 500) {
    // 503 temporarily_unavailable：本次请求未受理，稍后用原幂等键重试；其他 5xx 结果未知
    if (data?.error?.code === 'temporarily_unavailable')
      return { next: 'retry_same_key_later', requestId };
    return { next: 'unknown', requestId };
  }
  const error = data?.error ?? {};
  switch (error.code) {
    case 'payment_in_progress':
    case 'order_no_conflict':
    case 'refund_no_conflict':
      return { next: 'query_existing', id: error.related_resource_id, requestId };
    case 'operation_in_progress':
      return { next: 'retry_same_key', afterSeconds: 2, requestId };
    case 'idempotency_conflict':
      return { next: 'fix_integration', requestId }; // 同键不同参数：修复幂等键生成并告警
    default:
      return {
        next: 'rejected',
        httpStatus: res.status,
        code: error.code,
        field: error.field,
        message: error.message,
        requestId
      };
  }
}