import { Room } from 'matrix-js-sdk';
import { useMemo } from 'react';
import { useStateEvent } from './useStateEvent';
import { StateEvent } from '../../types/matrix/room';
import { VoiceLimitContent } from '../features/common-settings/general/RoomVoiceLimit';
import { useCallMembers, useCallSession } from './useCall';
import { useMatrixClient } from './useMatrixClient';

export type VoiceChannelFull = {
  channelFull: boolean;
  current: number;
  max: number;
};

/**
 * [Gitea #30] Voice channel user limit (`io.lotus.voice_limit`), shared between
 * `CallPrescreen` and any other join path (e.g. the room-nav second-click join)
 * so they agree on when a channel is full. 0/absent `max_users` means no limit.
 */
export const useVoiceChannelFull = (room: Room): VoiceChannelFull => {
  const mx = useMatrixClient();
  const callSession = useCallSession(room);
  const callMembers = useCallMembers(callSession);

  const limitEvent = useStateEvent(room, StateEvent.LotusVoiceLimit);

  return useMemo(() => {
    const maxUsers = limitEvent?.getContent<VoiceLimitContent>().max_users ?? 0;
    // A user already counted in the session is rejoining and should not be blocked.
    const alreadyMember = callMembers.some((m) => m.sender === mx.getSafeUserId());
    const channelFull = maxUsers > 0 && !alreadyMember && callMembers.length >= maxUsers;
    return { channelFull, current: callMembers.length, max: maxUsers };
  }, [limitEvent, callMembers, mx]);
};