cinny/src/app/hooks/useScreenshareNotices.ts

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

export type ScreenshareNoticeKind = 'ended' | 'no-frames' | 'alone';

export const describeScreenshareNotice = (kind: ScreenshareNoticeKind): string | undefined => {
  switch (kind) {
    case 'ended':
      return 'Screen sharing stopped — the shared window was closed.';
    case 'no-frames':
      return 'Your screen share is showing nothing — the shared window may be minimised or hidden.';
    case 'alone':
      return "Still sharing? You've been sharing your screen for 30 minutes with nobody else in the call.";
    default:
      return undefined;
  }
};

/** Pure: a policy-forced stop is explained by its own toast (#297). */
export const shouldShowScreenshareNotice = (
  kind: ScreenshareNoticeKind,
  allowScreenshare: boolean,
): boolean => !(kind === 'ended' && !allowScreenshare);

/**
 * [Gitea EC#39] Toast the fork's io.lotus.screenshare_notice: shared window
 * closed, no frames for a while, or a long share with nobody watching.
 */
export function useScreenshareNotices(embed: CallEmbed): void {
  const setToast = useSetAtom(toastQueueAtom);
  // [Gitea #297] When a room admin turns screen sharing off, the share ends
  // and the fork reports `ended` ("the shared window was closed"), which is
  // wrong; useCallPolicyRevokedToast already says what happened.
  const { allowScreenshare } = useRoomCallPolicy(embed.room);
  const allowRef = useRef(allowScreenshare);
  allowRef.current = allowScreenshare;
  useEffect(
    () =>
      embed.listenAction<{ data?: { kind?: ScreenshareNoticeKind } }>(
        'io.lotus.screenshare_notice',
        (evt) => {
          const kind = evt.detail?.data?.kind as ScreenshareNoticeKind;
          if (!shouldShowScreenshareNotice(kind, allowRef.current)) return;
          const body = describeScreenshareNotice(kind);
          if (!body) return;
          setToast({
            id: `screenshare-${evt.detail?.data?.kind}-${Date.now()}`,
            iconSrc: Icons.ScreenShare,
            displayName: 'Screen share',
            body,
            roomName: embed.room.name ?? 'Voice call',
            roomId: embed.roomId,
            sticky: evt.detail?.data?.kind === 'alone',
          });
        },
      ),
    [embed, setToast],
  );
}