import { JitsiTrackErrors } from '../lib-jitsi-meet';

/**
 * Attach a set of local tracks to a conference.
 *
 * NOTE The function is internal to this feature.
 *
 * @param {JitsiConference} conference - Conference instance.
 * @param {JitsiLocalTrack[]} localTracks - List of local media tracks.
 * @returns {Promise}
 */
export function _addLocalTracksToConference(conference, localTracks) {
    const conferenceLocalTracks = conference.getLocalTracks();
    const promises = [];

    for (const track of localTracks) {
        // XXX The library lib-jitsi-meet may be draconian, for example, when
        // adding one and the same video track multiple times.
        if (conferenceLocalTracks.indexOf(track) === -1) {
            promises.push(
                conference.addTrack(track).catch(err => {
                    _reportError(
                        'Failed to add local track to conference',
                        err);
                }));
        }
    }

    return Promise.all(promises);
}

/**
 * Handle an error thrown by the backend (i.e. lib-jitsi-meet) while
 * manipulating a conference participant (e.g. pin or select participant).
 *
 * NOTE The function is internal to this feature.
 *
 * @param {Error} err - The Error which was thrown by the backend while
 * manipulating a conference participant and which is to be handled.
 * @returns {void}
 */
export function _handleParticipantError(err) {
    // XXX DataChannels are initialized at some later point when the conference
    // has multiple participants, but code that pins or selects a participant
    // might be executed before. So here we're swallowing a particular error.
    // TODO Lib-jitsi-meet should be fixed to not throw such an exception in
    // these scenarios.
    if (err.message !== 'Data channels support is disabled!') {
        throw err;
    }
}

/**
 * Determines whether a specific string is a valid room name.
 *
 * @param {(string|undefined)} room - The name of the conference room to check
 * for validity.
 * @returns {boolean} If the specified room name is valid, then true; otherwise,
 * false.
 */
export function isRoomValid(room) {
    return typeof room === 'string' && room !== '';
}

/**
 * Remove a set of local tracks from a conference.
 *
 * NOTE The function is internal to this feature.
 *
 * @param {JitsiConference} conference - Conference instance.
 * @param {JitsiLocalTrack[]} localTracks - List of local media tracks.
 * @returns {Promise}
 */
export function _removeLocalTracksFromConference(conference, localTracks) {
    return Promise.all(localTracks.map(track =>
        conference.removeTrack(track)
            .catch(err => {
                // Local track might be already disposed by direct
                // JitsiTrack#dispose() call. So we should ignore this error
                // here.
                if (err.name !== JitsiTrackErrors.TRACK_IS_DISPOSED) {
                    _reportError(
                        'Failed to remove local track from conference',
                        err);
                }
            })
    ));
}

/**
 * Reports a specific Error with a specific error message. While the
 * implementation merely logs the specified msg and err via the console at the
 * time of this writing, the intention of the function is to abstract the
 * reporting of errors and facilitate elaborating on it in the future.
 *
 * NOTE The function is internal to this feature.
 *
 * @param {string} msg - The error message to report.
 * @param {Error} err - The Error to report.
 * @private
 * @returns {void}
 */
function _reportError(msg, err) {
    // TODO This is a good point to call some global error handler when we have
    // one.
    console.error(msg, err);
}