"use client";

// The official instances' numbers, composed at hub build time
// (common/bin/compose-hub.ts -> /hub-summary.json) from the same summary the
// homepage renders. Same-origin, fetched once. OPTIONAL: an older hub build or
// a hub composed with no index has no file, and every failure — 404, bad JSON,
// an unknown version — reads as "no numbers", never as an error on the page.
//
// `settled` turns true once the answer is in, whatever it was: the hub lists
// its official instances in the summary's order (useHubSites), so it waits for
// this before listing them rather than reordering them a moment later.

import { useQuery } from "@tanstack/react-query";
import {
  HUB_SUMMARY_FILE,
  parseHubSummary,
  type HubSummary,
} from "yt-dlp-transcript-common/lib/hubSummary";

async function fetchHubSummary(): Promise<HubSummary | null> {
  try {
    const res = await fetch(`/${HUB_SUMMARY_FILE}`);
    if (!res.ok) return null;
    return parseHubSummary(await res.json());
  } catch {
    return null;
  }
}

export function useHubSummary(): {
  summary: HubSummary | null;
  settled: boolean;
} {
  const { data, isPending } = useQuery({
    queryKey: ["hub-summary"],
    queryFn: fetchHubSummary,
    staleTime: Infinity,
    retry: false,
    // Always run it, even while the browser reports itself offline: TanStack's
    // default ("online") would PAUSE the query then, leaving it pending and the
    // official instances unlisted until the connection returned. The fetch
    // never throws — offline it settles at once as "no summary".
    networkMode: "always",
  });
  return { summary: data ?? null, settled: !isPending };
}