var RTCPeerConnection = null;
var getUserMedia = null;
var attachMediaStream = null;
var reattachMediaStream = null;
var webrtcDetectedBrowser = null;

function trace(text) {
    // This function is used for logging.
    if (text[text.length - 1] == '\n') {
        text = text.substring(0, text.length - 1);
    }
    console.log((performance.now() / 1000).toFixed(3) + ": " + text);
}

if (navigator.mozGetUserMedia) {
    console.log("This appears to be Firefox");

    webrtcDetectedBrowser = "firefox";

    // The RTCPeerConnection object.
    RTCPeerConnection = mozRTCPeerConnection;

    // The RTCSessionDescription object.
    RTCSessionDescription = mozRTCSessionDescription;

    // The RTCIceCandidate object.
    RTCIceCandidate = mozRTCIceCandidate;

    // Get UserMedia (only difference is the prefix).
    // Code from Adam Barth.
    getUserMedia = navigator.mozGetUserMedia.bind(navigator);

    // Attach a media stream to an element.
    attachMediaStream = function(element, stream) {
        console.log("Attaching media stream");
        element.mozSrcObject = stream;
        element.play();
    };

    reattachMediaStream = function(to, from) {
        console.log("Reattaching media stream");
        to.mozSrcObject = from.mozSrcObject;
        to.play();
    };

    // Fake get{Video,Audio}Tracks
    MediaStream.prototype.getVideoTracks = function() {
        return [];
    };

    MediaStream.prototype.getAudioTracks = function() {
        return [];
    };
} else if (navigator.webkitGetUserMedia) {
    console.log("This appears to be Chrome");

    webrtcDetectedBrowser = "chrome";

    // The RTCPeerConnection object.
    RTCPeerConnection = webkitRTCPeerConnection;

    // Get UserMedia (only difference is the prefix).
    // Code from Adam Barth.
    getUserMedia = navigator.webkitGetUserMedia.bind(navigator);

    // Attach a media stream to an element.
    attachMediaStream = function(element, stream) {
        if (typeof element.srcObject !== 'undefined') {
            element.srcObject = stream;
        } else if (typeof element.mozSrcObject !== 'undefined') {
            element.mozSrcObject = stream;
        } else if (typeof element.src !== 'undefined') {
            element.src = URL.createObjectURL(stream);
        } else {
            console.log('Error attaching stream to element.');
        }
    };

    reattachMediaStream = function(to, from) {
        to.src = from.src;
    };

    // The representation of tracks in a stream is changed in M26.
    // Unify them for earlier Chrome versions in the coexisting period.
    if (!webkitMediaStream.prototype.getVideoTracks) {
        webkitMediaStream.prototype.getVideoTracks = function() {
            return this.videoTracks;
        };
        webkitMediaStream.prototype.getAudioTracks = function() {
            return this.audioTracks;
        };
    }

    // New syntax of getXXXStreams method in M26.
    if (!webkitRTCPeerConnection.prototype.getLocalStreams) {
        webkitRTCPeerConnection.prototype.getLocalStreams = function() {
            console.log(this);
            return this.localStreams;
        };
        webkitRTCPeerConnection.prototype.getRemoteStreams = function() {
            return this.remoteStreams;
        };
    }
} else {
    console.log("Browser does not appear to be WebRTC-capable");
}
