// The swarm forge's base URL, from `GET /api/links`. Fetched once and shared by
// every agent card, so opening many cards sends one request. A failed fetch
// is not kept, so the next card retries; the links just stay hidden meanwhile.
import { useEffect, useState } from "preact/hooks";
import type { MenuLink } from "@hive/shared/links-menu.js";
import { forgeBase } from "./forge-links.js";

let pending: Promise<string | null> | null = null;

function loadForgeBase(): Promise<string | null> {
  if (!pending) {
    pending = fetch("/api/links")
      .then((r) =>
        r.ok
          ? (r.json() as Promise<MenuLink[]>)
          : Promise.reject(new Error(`http ${r.status}`)),
      )
      .then(forgeBase)
      .catch(() => {
        pending = null;
        return null;
      });
  }
  return pending;
}

/** The forge's base URL, or null until known (or when the swarm lists none). */
export function useForgeBase(): string | null {
  const [base, setBase] = useState<string | null>(null);
  useEffect(() => {
    let live = true;
    void loadForgeBase().then((b) => {
      if (live) setBase(b);
    });
    return () => {
      live = false;
    };
  }, []);
  return base;
}