export async function withRetry<T>(
  operation: () => Promise<T>,
  maxAttempts = 3,
): Promise<T> {
  let delay = 500;
  let lastError: unknown;

  for (let attempt = 0; attempt < maxAttempts; attempt++) {
    try {
      return await operation();
    } catch (err) {
      lastError = err;
      if (attempt < maxAttempts - 1) {
        await new Promise((r) => setTimeout(r, delay));
        delay *= 2;
      }
    }
  }

  throw lastError;
}

export function parseRetryAfter(headers: Headers): number | null {
  const value = headers.get("retry-after");
  if (!value) return null;
  const seconds = Number(value);
  return Number.isFinite(seconds) ? seconds * 1000 : null;
}