Class(function GameCenterRTC(_id, _socket, _initiator) {
    Inherit(this, Component);
    var _this = this;
    var _peer, _data;

    //*** Constructor
    (function () {
        initPeerConnection();
        if (_initiator) initConnection();
    })();

    function initPeerConnection() {
        _peer = new RTCPeerConnection({"iceServers":[{"urls":"stun:stun.l.google.com:19302"}]});

        _peer.onicecandidate = e => {
            if (!_peer || !e || !e.candidate || !e.candidate.candidate) return console.warn('failed ice candidate');
            sendNegotiation('candidate', e.candidate);
        };

        _data = _peer.createDataChannel('gamecenter', {ordered: false, negotiated: true, id: 7});
        _data.onmessage = dataMessage;
        _data.onopen = dataOpen;
        _data.onclose = dataClose;
        _data.onerror = dataError;

        if (DEBUG) console.log('GC::init peer connection', _peer)
        _peer.ondatachannel = e => {
            e.channel.onmessage = dataMessage;
            e.channel.onclose = dataClose;
            e.channel.onerror = dataError;
        }
    }

    async function initConnection() {
        let sdp;
        try {
            sdp = await _peer.createOffer();
        } catch(e) {
            console.error(e);
        }
        if (DEBUG) console.log('GC::after create offer');

        _peer.setLocalDescription(sdp);
        sendNegotiation('offer', sdp);
    }

    function sendNegotiation(type, sdp) {
        let data = {to: _id, type, sdp};
        _socket.send('establish_rtc', data);
    }

    //*** Event handlers
    async function processOffer(offer) {
        try {
            await _peer.setRemoteDescription(new RTCSessionDescription(offer));

            let sdp = await _peer.createAnswer();
            _peer.setLocalDescription(sdp);
            sendNegotiation('answer', sdp);
        } catch(e) {
            //handle error
        }
    }

    async function processAnswer(answer) {
        try {
            await _peer.setRemoteDescription(new RTCSessionDescription(answer));
        } catch(e) {
            //handle error
        }
    }

    function processIce(iceCandidate) {
        try {
            _peer.addIceCandidate(new RTCIceCandidate(iceCandidate));
        } catch(e) {
            //handle error
        }
    }

    function dataMessage(e) {
        //handle message
    }

    function dataOpen(e) {
        //handle open
    }

    function dataClose(e) {
        //handle close
    }

    function dataError(e) {
        //handle error
    }

    //*** Public methods
    this.establish = function(data) {
        if (!_peer) return;

        switch (data.type) {
            case 'candidate':
                processIce(data.sdp);
                break;

            case 'offer':
                processOffer(data.sdp);
                break;

            case 'answer':
                processAnswer(data.sdp);
                break;
        }
    }

    this.emit = function(data = {}) {
        if (_data.readyState != 'open') return;
        data.from = GameCenter.GCID;
        _data.send(JSON.stringify(data));
    }

    this.close = function() {
        _peer && _peer.close();
        _peer = null;
    }
});