/* ═══════════════════════════════════════════════════════════════
   ADMIN TITLE

   The layout knows which section you're in; only the page knows
   which record is on screen. Rather than have both write
   document.title and race — child effects run before parent
   effects, so the layout would win and the record name would
   never survive — the page publishes a string and the layout is
   the single writer.

   Null is the normal state. A page that publishes nothing, or one
   still loading, simply leaves the section title showing.
   ═══════════════════════════════════════════════════════════════ */

import { createContext, useContext, useEffect } from "react";

export type AdminTitleValue = { setDetail: (value: string | null) => void };

export const AdminTitleContext = createContext<AdminTitleValue | null>(null);

/* Publish the name of whatever this page is showing. Clears on
   unmount, so navigating away can't leave a stale record name in
   the tab. */
export function useAdminDetail(name: string | null | undefined) {
  const setDetail = useContext(AdminTitleContext)?.setDetail;

  useEffect(() => {
    if (!setDetail) return undefined;
    setDetail(name || null);
    return () => setDetail(null);
  }, [setDetail, name]);
}