var ws = new WebSocket('ws://' + location.host + '/ws');
var pc;
function call() {
    document.getElementById('btn-call').className += ' btn-active';
    init(true);
}
function receive() {
    document.getElementById('btn-receive').className += ' btn-active';
    init(false);
}
function init(initiator) {
    var constraints = {
        audio: document.getElementById('audio').checked,
        video: document.getElementById('video').checked
    };
    
    getUserMedia(constraints, function(stream) {
        pc = new RTCPeerConnection(null);
        
        pc.addStream(stream);
        attachMediaStream(document.getElementById('local'), stream);
        pc.onaddstream = function(event) {
            attachMediaStream(document.getElementById('remote'), event.stream);
        };
        pc.onicecandidate = function(event) {
            if (event.candidate) {
                ws.send(JSON.stringify(event.candidate));
            }
        };
        ws.onmessage = function (event) {
            var signal = JSON.parse(event.data);
            if (signal.sdp) {
                if (initiator) {
                    receiveAnswer(signal);
                } else {
                    receiveOffer(signal);
                }
            } else if (signal.candidate) {
                pc.addIceCandidate(new RTCIceCandidate(signal));
            }
        };
        
        if (initiator) {
            createOffer();
        }
    }, fail);
}
function createOffer() {
    console.log('creating offer');
    pc.createOffer(function(offer) {
        console.log('created offer');
        pc.setLocalDescription(offer, function() {
            console.log('setLocalDescription done, sending to remote');
            ws.send(JSON.stringify(offer));
        }, fail);
    }, fail);
}
function receiveOffer(offer) {
    console.log('received offer');
    pc.setRemoteDescription(new RTCSessionDescription(offer), function() {
        console.log('creating answer');
        pc.createAnswer(function(answer) {
            console.log('created answer');
            pc.setLocalDescription(answer, function() {
                console.log('setLocalDescription done, sending to remote');
                ws.send(JSON.stringify(answer));
            }, fail);
        }, fail);
    }, fail);
}
function receiveAnswer(answer) {
    console.log('received answer');
    pc.setRemoteDescription(new RTCSessionDescription(answer));
}
function fail(error) {
    console.log(error);
}