import MediaStream from './MediaStream';
import type MediaStreamTrack from './MediaStreamTrack';
import RTCRtpReceiver from './RTCRtpReceiver';
import RTCRtpTransceiver from './RTCRtpTransceiver';
import { Event } from './vendor/event-target-shim';

type TRACK_EVENTS = 'track'

interface IRTCTrackEventInitDict extends Event.EventInit {
    streams: MediaStream[]
    transceiver: RTCRtpTransceiver
}

/**
 * @eventClass
 * This event is fired whenever the Track is changed in PeerConnection.
 * @param {TRACK_EVENTS} type - The type of event.
 * @param {IRTCTrackEventInitDict} eventInitDict - The event init properties.
 * @see {@link https://developer.mozilla.org/en-US/docs/Web/API/RTCPeerConnection/track_event MDN} for details.
 */
export default class RTCTrackEvent<TEventType extends TRACK_EVENTS> extends Event<TEventType> {
    /** @eventProperty */
    readonly streams: MediaStream[] = [];

    /** @eventProperty */
    readonly transceiver: RTCRtpTransceiver;

    /** @eventProperty */
    readonly receiver: RTCRtpReceiver | null;

    /** @eventProperty */
    readonly track: MediaStreamTrack | null;

    constructor(type: TEventType, eventInitDict: IRTCTrackEventInitDict) {
        super(type, eventInitDict);
        this.streams = eventInitDict.streams;
        this.transceiver = eventInitDict.transceiver;
        this.receiver = eventInitDict.transceiver.receiver;
        this.track = eventInitDict.transceiver.receiver ? eventInitDict.transceiver.receiver.track : null;
    }
}