const BASE = `${process.env.DATAVERSE_URL}/api/data/v9.2`;
const MAX_RETRIES = 3;

function sleep(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

// Reintenta 429 (throttling de Dataverse) respetando Retry-After — ver migration.md §8.
export async function dv(path, accessToken, attempt = 0) {
  const r = await fetch(`${BASE}/${path}`, {
    headers: {
      Authorization: `Bearer ${accessToken}`,
      Accept: "application/json",
      "OData-MaxVersion": "4.0",
      "OData-Version": "4.0",
      Prefer: 'odata.include-annotations="OData.Community.Display.V1.FormattedValue"',
    },
    cache: "no-store", // decisión: sin caché, datos en vivo
  });
  if (r.status === 401) throw new Error("TOKEN_EXPIRED");
  if (r.status === 429 && attempt < MAX_RETRIES) {
    const retryAfter = Number(r.headers.get("Retry-After")) || 2 ** attempt;
    await sleep(retryAfter * 1000);
    return dv(path, accessToken, attempt + 1);
  }
  if (!r.ok) throw new Error(`DATAVERSE_${r.status}: ${(await r.text()).slice(0, 300)}`);
  return r.json();
}

// Etiqueta legible de un option set, entregada por el header Prefer de arriba.
export function fv(o, key) {
  return o[`${key}@OData.Community.Display.V1.FormattedValue`] || null;
}

export function odataString(s) {
  return String(s).replace(/'/g, "''");
}