import type { AxiosResponseHeaders, RawAxiosResponseHeaders } from "axios";

export async function withRetry<T>(
  fn: () => Promise<T>,
  retry: number = 0
): Promise<T> {
  let lastErr;
  for (let i = 0; i <= retry; i++) {
    try { return await fn(); }
    catch (e) { lastErr = e; }
  }
  throw lastErr;
}

export type AxiosLikeHeaders =
  | AxiosResponseHeaders
  | Partial<RawAxiosResponseHeaders>
  | Record<string, unknown>
  | undefined;

export function normalizeHeaders(headers: AxiosLikeHeaders): Record<string, string> {
  const out: Record<string, string> = {};

  if (!headers) return out;

  for (const [key, value] of Object.entries(headers)) {
    if (value === undefined || value === null) continue;

    if (Array.isArray(value)) {
      out[key] = value.map(String).join(", ");
      continue;
    }

    out[key] = String(value);
  }

  return out;
}