import { useEffect, useRef } from 'react';
import { useSetAtom } from 'jotai';
import { CallEmbed, useCallControlState } from '../plugins/call';
import { useRoomCallPolicy } from './useRoomCallPolicy';
import { toastQueueAtom } from '../state/toast';

/**
 * [Gitea #223] When a room admin turns Allow Screen Sharing / Allow Camera
 * off mid-call, the voice-limit-guard revokes the publish permission and the
 * SFU drops our track within seconds — the button just vanishes with no
 * explanation. Tell the user why: a track that went away while the room policy
 * forbids it was not their doing.
 */
export function useCallPolicyRevokedToast(embed: CallEmbed, joined: boolean): void {
  const { screenshare, video } = useCallControlState(embed.control);
  const { allowScreenshare, allowCamera } = useRoomCallPolicy(embed.room);
  const setToast = useSetAtom(toastQueueAtom);
  const prev = useRef({ screenshare, video });

  useEffect(() => {
    const was = prev.current;
    prev.current = { screenshare, video };
    if (!joined) return;
    const notify = (body: string) =>
      setToast({
        id: `call-policy-${Date.now()}`,
        displayName: 'Lotus Chat',
        body,
        roomName: embed.room.name ?? 'Voice call',
        roomId: embed.roomId,
      });
    if (was.screenshare && !screenshare && !allowScreenshare) {
      notify('Screen sharing was turned off by a room admin.');
    }
    if (was.video && !video && !allowCamera) {
      notify('Your camera was turned off by a room admin.');
    }
  }, [screenshare, video, allowScreenshare, allowCamera, joined, setToast, embed]);
}