Open video sync

/** Every page or an exception (429/503/network are retried inside `call`). Never replace your list with a partial sweep. */
export async function sweep(o: CallOptions = {}): Promise<{ rows: OpenVideo[]; refreshAt: Date }> {
  const rows = new Map<string, OpenVideo>();
  let cursor: string | null = null;
  let refreshAt: Date | null = null;
  for (let page = 0; page < 10_000; page++) {
    const qs: string = `limit=200${cursor ? `&cursor=${encodeURIComponent(cursor)}` : ''}`;
    const { data }: { data: Page } = await call<Page>('GET', `/api/delivery/v1/videos?${qs}`, { policy: BACKGROUND, ...o });
    for (const r of data.rows) rows.set(r.id, r); // key by `id`, never by title
    const rb = new Date(data.refresh_before); // earlier pages expire first: keep the EARLIEST deadline
    if (!refreshAt || rb < refreshAt) refreshAt = rb;
    cursor = data.next_cursor;
    if (cursor === null) return { rows: [...rows.values()], refreshAt }; // a short or empty page is NOT the end
  }
  throw new Error('open video sweep did not end');
}

let current: { rows: OpenVideo[]; refreshAt: Date } | null = null;

/** Keeps `current` fresh. On failure keeps serving the previous list and tries again in a minute. */
export async function refreshLoop(o: CallOptions = {}): Promise<void> {
  let delay = 60_000;
  try {
    current = await sweep(o);
    delay = Math.max(60_000, current.refreshAt.getTime() - Date.now());
  } catch {
    // previous links stay valid until their own expiry
  }
  setTimeout(() => void refreshLoop(o), delay).unref();
}
/** What your app receives: links from your server's cache. Apps never store them. */
export const currentRows = (): OpenVideo[] => current?.rows ?? [];