import { Channel } from './channel.interface';
import { GLOBAL_FAVORITES_PLAYLIST_ID } from './constants';
import { Playlist } from './playlist.interface';

/**
 * Aggregates favorite channels as objects from all available playlists
 * @param playlists all available playlists
 * @returns an array with favorite channels from all playlists
 */
export function aggregateFavoriteChannels(playlists: Playlist[]): Channel[] {
    const favorites = [];
    playlists.forEach((playlist) => {
        if (playlist.favorites?.length > 0) {
            playlist.playlist.items.forEach((channel) => {
                if (playlist.favorites.includes(channel.id)) {
                    favorites.push(channel);
                }
            });
        }
    });
    return favorites;
}

/**
 * Creates a simplified playlist object which is used for global favorites
 * @param channels channels list
 * @returns simplified playlist object
 */
export function createFavoritesPlaylist(
    channels: Channel[]
): Partial<Playlist> {
    return {
        id: GLOBAL_FAVORITES_PLAYLIST_ID,
        _id: GLOBAL_FAVORITES_PLAYLIST_ID,
        count: channels.length,
        playlist: {
            items: channels,
        },
    };
}