{
  "error": {
    "type": "not_found",
    "code": "file_not_found",
    "message": "Canvas cvs_abc123 not found",
    "doc_url": "https://docs.moda.app/errors/file_not_found",
    "request_id": "019d8996-16b3-73ee-841a-5bc5038eb972",
    "details": null,
    "retry_after_ms": null,
    "causes": null
  }
}

async function modaFetch(path: string, init?: RequestInit) {
  const res = await fetch(`https://api.moda.app${path}`, {
    ...init,
    headers: { ...HEADERS, ...(init?.headers ?? {}) },
  });
  if (res.ok) return res.json();

  const body = await res.json().catch(() => null);
  const err = body?.error;
  if (!err) throw new Error(`Moda ${res.status} (no envelope)`);

  if (err.type === "rate_limited" || err.type === "upstream_error" || err.type === "internal_error") {
    const ra = Number(res.headers.get("Retry-After") ?? 0) * 1000 || err.retry_after_ms || 3000;
    await new Promise(r => setTimeout(r, ra));
    return modaFetch(path, init); // caller should cap recursion
  }

  throw new Error(
    `Moda ${err.type}/${err.code}: ${err.message} (request_id=${err.request_id})`,
  );
}

import time, httpx

def moda_fetch(client: httpx.Client, method: str, path: str, *, attempt: int = 1, **kw):
    r = client.request(method, path, **kw)
    if r.is_success:
        return r.json()

    body = r.json() if r.headers.get("content-type", "").startswith("application/json") else {}
    err = body.get("error") or {}

    retryable = {"rate_limited", "upstream_error", "internal_error"}
    if err.get("type") in retryable and attempt <= 3:
        ra = int(r.headers.get("Retry-After", 0)) or ((err.get("retry_after_ms") or 3000) // 1000) or 3
        time.sleep(ra)
        return moda_fetch(client, method, path, attempt=attempt + 1, **kw)

    raise RuntimeError(
        f"Moda {err.get('type')}/{err.get('code')}: {err.get('message')} "
        f"(request_id={err.get('request_id')})"
    )