import { useCallback, useRef } from 'react';
import { defineChannel } from 'hooks/usePanelChannel';

/**
 * "The connection changed — anything reading it should read it again."
 *
 * A channel and not the URL, because `docs/navigation-audit.md` draws that line at ADDRESSABLE: nobody
 * links to the moment after a connection was saved, and there is nothing selected. This is the second
 * kind — a signal.
 *
 * The nonce is a module counter rather than `setSignal(n => n + 1)`, copied deliberately from
 * proxy-manager's own channel, which records why: the functional setter applies against the value
 * captured at render, so two bumps in one render window both compute `snapshot + 1` and the second is
 * lost. `Date.now()` has the same flaw twice in a millisecond. A module counter never reads React state.
 */
const useOpenSeoChangedChannel = defineChannel<number>('openseo:changed', 0);

let nonce = 0;

export const useOpenSeoChanged = () => {
  const [signal, setSignal] = useOpenSeoChangedChannel();
  const setRef = useRef(setSignal);
  setRef.current = setSignal;
  const bump = useCallback(() => setRef.current(++nonce), []);
  return [signal, bump] as const;
};