function TraceablePeerConnection(ice_config, constraints) {
    var self = this;
    var RTCPeerconnection = navigator.mozGetUserMedia ? mozRTCPeerConnection : webkitRTCPeerConnection;
    this.peerconnection = new RTCPeerconnection(ice_config, constraints);
    this.updateLog = [];
    this.stats = {};
    this.statsinterval = null;
    this.maxstats = 0; // limit to 300 values, i.e. 5 minutes; set to 0 to disable
    var Interop = require('sdp-interop').Interop;
    this.interop = new Interop();
    var Simulcast = require('sdp-simulcast');
    this.simulcast = new Simulcast({numOfLayers: 3, explodeRemoteSimulcast: false});

    // override as desired
    this.trace = function (what, info) {
        //console.warn('WTRACE', what, info);
        self.updateLog.push({
            time: new Date(),
            type: what,
            value: info || ""
        });
    };
    this.onicecandidate = null;
    this.peerconnection.onicecandidate = function (event) {
        self.trace('onicecandidate', JSON.stringify(event.candidate, null, ' '));
        if (self.onicecandidate !== null) {
            self.onicecandidate(event);
        }
    };
    this.onaddstream = null;
    this.peerconnection.onaddstream = function (event) {
        self.trace('onaddstream', event.stream.id);
        if (self.onaddstream !== null) {
            self.onaddstream(event);
        }
    };
    this.onremovestream = null;
    this.peerconnection.onremovestream = function (event) {
        self.trace('onremovestream', event.stream.id);
        if (self.onremovestream !== null) {
            self.onremovestream(event);
        }
    };
    this.onsignalingstatechange = null;
    this.peerconnection.onsignalingstatechange = function (event) {
        self.trace('onsignalingstatechange', self.signalingState);
        if (self.onsignalingstatechange !== null) {
            self.onsignalingstatechange(event);
        }
    };
    this.oniceconnectionstatechange = null;
    this.peerconnection.oniceconnectionstatechange = function (event) {
        self.trace('oniceconnectionstatechange', self.iceConnectionState);
        if (self.oniceconnectionstatechange !== null) {
            self.oniceconnectionstatechange(event);
        }
    };
    this.onnegotiationneeded = null;
    this.peerconnection.onnegotiationneeded = function (event) {
        self.trace('onnegotiationneeded');
        if (self.onnegotiationneeded !== null) {
            self.onnegotiationneeded(event);
        }
    };
    self.ondatachannel = null;
    this.peerconnection.ondatachannel = function (event) {
        self.trace('ondatachannel', event);
        if (self.ondatachannel !== null) {
            self.ondatachannel(event);
        }
    };
    if (!navigator.mozGetUserMedia && this.maxstats) {
        this.statsinterval = window.setInterval(function() {
            self.peerconnection.getStats(function(stats) {
                var results = stats.result();
                for (var i = 0; i < results.length; ++i) {
                    //console.log(results[i].type, results[i].id, results[i].names())
                    var now = new Date();
                    results[i].names().forEach(function (name) {
                        var id = results[i].id + '-' + name;
                        if (!self.stats[id]) {
                            self.stats[id] = {
                                startTime: now,
                                endTime: now,
                                values: [],
                                times: []
                            };
                        }
                        self.stats[id].values.push(results[i].stat(name));
                        self.stats[id].times.push(now.getTime());
                        if (self.stats[id].values.length > self.maxstats) {
                            self.stats[id].values.shift();
                            self.stats[id].times.shift();
                        }
                        self.stats[id].endTime = now;
                    });
                }
            });

        }, 1000);
    }
};

dumpSDP = function(description) {
    if (typeof description === 'undefined' || description == null) {
        return '';
    }

    return 'type: ' + description.type + '\r\n' + description.sdp;
};

if (TraceablePeerConnection.prototype.__defineGetter__ !== undefined) {
    TraceablePeerConnection.prototype.__defineGetter__('signalingState', function() { return this.peerconnection.signalingState; });
    TraceablePeerConnection.prototype.__defineGetter__('iceConnectionState', function() { return this.peerconnection.iceConnectionState; });
    TraceablePeerConnection.prototype.__defineGetter__('localDescription', function() {
        var desc = this.peerconnection.localDescription;
        this.trace('getLocalDescription::preTransform', dumpSDP(desc));

        // if we're running on FF, transform to Plan B first.
        if (navigator.mozGetUserMedia) {
            desc = this.interop.toPlanB(desc);
            this.trace('getLocalDescription::postTransform (Plan B)', dumpSDP(desc));
        }
        return desc;
    });
    TraceablePeerConnection.prototype.__defineGetter__('remoteDescription', function() {
        var desc = this.peerconnection.remoteDescription;
        this.trace('getRemoteDescription::preTransform', dumpSDP(desc));

        // if we're running on FF, transform to Plan B first.
        if (navigator.mozGetUserMedia) {
            desc = this.interop.toPlanB(desc);
            this.trace('getRemoteDescription::postTransform (Plan B)', dumpSDP(desc));
        }
        return desc;
    });
}

TraceablePeerConnection.prototype.addStream = function (stream) {
    this.trace('addStream', stream.id);
    try
    {
        this.peerconnection.addStream(stream);
    }
    catch (e)
    {
        console.error(e);
        return;
    }
};

TraceablePeerConnection.prototype.removeStream = function (stream, stopStreams) {
    this.trace('removeStream', stream.id);
    if(stopStreams) {
        stream.getAudioTracks().forEach(function (track) {
            track.stop();
        });
        stream.getVideoTracks().forEach(function (track) {
            track.stop();
        });
    }

    try {
        // FF doesn't support this yet.
        this.peerconnection.removeStream(stream);
    } catch (e) {
        console.error(e);
    }
};

TraceablePeerConnection.prototype.createDataChannel = function (label, opts) {
    this.trace('createDataChannel', label, opts);
    return this.peerconnection.createDataChannel(label, opts);
};

TraceablePeerConnection.prototype.setLocalDescription = function (description, successCallback, failureCallback) {
    this.trace('setLocalDescription::preTransform', dumpSDP(description));
    // if we're running on FF, transform to Plan A first.
    if (navigator.mozGetUserMedia) {
        description = this.interop.toUnifiedPlan(description);
        this.trace('setLocalDescription::postTransform (Plan A)', dumpSDP(description));
    }

    var self = this;
    this.peerconnection.setLocalDescription(description,
        function () {
            self.trace('setLocalDescriptionOnSuccess');
            successCallback();
        },
        function (err) {
            self.trace('setLocalDescriptionOnFailure', err);
            failureCallback(err);
        }
    );
    /*
     if (this.statsinterval === null && this.maxstats > 0) {
     // start gathering stats
     }
     */
};

TraceablePeerConnection.prototype.setRemoteDescription = function (description, successCallback, failureCallback) {
    this.trace('setRemoteDescription::preTransform', dumpSDP(description));
    // TODO the focus should squeze or explode the remote simulcast
    description = this.simulcast.mungeRemoteDescription(description);
    this.trace('setRemoteDescription::postTransform (simulcast)', dumpSDP(description));

    // if we're running on FF, transform to Plan A first.
    if (navigator.mozGetUserMedia) {
        description = this.interop.toUnifiedPlan(description);
        this.trace('setRemoteDescription::postTransform (Plan A)', dumpSDP(description));
    }
    var self = this;
    this.peerconnection.setRemoteDescription(description,
        function () {
            self.trace('setRemoteDescriptionOnSuccess');
            successCallback();
        },
        function (err) {
            self.trace('setRemoteDescriptionOnFailure', err);
            failureCallback(err);
        }
    );
    /*
     if (this.statsinterval === null && this.maxstats > 0) {
     // start gathering stats
     }
     */
};

TraceablePeerConnection.prototype.close = function () {
    this.trace('stop');
    if (this.statsinterval !== null) {
        window.clearInterval(this.statsinterval);
        this.statsinterval = null;
    }
    this.peerconnection.close();
};

TraceablePeerConnection.prototype.createOffer = function (successCallback, failureCallback, constraints) {
    var self = this;
    this.trace('createOffer', JSON.stringify(constraints, null, ' '));
    this.peerconnection.createOffer(
        function (offer) {
            self.trace('createOfferOnSuccess::preTransform', dumpSDP(offer));
            // if we're running on FF, transform to Plan B first.
            // NOTE this is not tested because in meet the focus generates the
            // offer.
            if (navigator.mozGetUserMedia) {
                offer = self.interop.toPlanB(offer);
                self.trace('createOfferOnSuccess::postTransform (Plan B)', dumpSDP(offer));
            }

            if (config.enableSimulcast && self.simulcast.isSupported()) {
                offer = self.simulcast.mungeLocalDescription(offer);
                self.trace('createOfferOnSuccess::postTransform (simulcast)', dumpSDP(offer));
            }
            successCallback(offer);
        },
        function(err) {
            self.trace('createOfferOnFailure', err);
            failureCallback(err);
        },
        constraints
    );
};

TraceablePeerConnection.prototype.createAnswer = function (successCallback, failureCallback, constraints) {
    var self = this;
    this.trace('createAnswer', JSON.stringify(constraints, null, ' '));
    this.peerconnection.createAnswer(
        function (answer) {
            self.trace('createAnswerOnSuccess::preTransfom', dumpSDP(answer));
            // if we're running on FF, transform to Plan A first.
            if (navigator.mozGetUserMedia) {
                answer = self.interop.toPlanB(answer);
                self.trace('createAnswerOnSuccess::postTransfom (Plan B)', dumpSDP(answer));
            }
            if (config.enableSimulcast && self.simulcast.isSupported()) {
                answer = self.simulcast.mungeLocalDescription(answer);
                self.trace('createAnswerOnSuccess::postTransfom (simulcast)', dumpSDP(answer));
            }
            successCallback(answer);
        },
        function(err) {
            self.trace('createAnswerOnFailure', err);
            failureCallback(err);
        },
        constraints
    );
};

TraceablePeerConnection.prototype.addIceCandidate = function (candidate, successCallback, failureCallback) {
    var self = this;
    this.trace('addIceCandidate', JSON.stringify(candidate, null, ' '));
    this.peerconnection.addIceCandidate(candidate);
    /* maybe later
     this.peerconnection.addIceCandidate(candidate,
     function () {
     self.trace('addIceCandidateOnSuccess');
     successCallback();
     },
     function (err) {
     self.trace('addIceCandidateOnFailure', err);
     failureCallback(err);
     }
     );
     */
};

TraceablePeerConnection.prototype.getStats = function(callback, errback) {
    if (navigator.mozGetUserMedia) {
        // ignore for now...
        if(!errback)
            errback = function () {

            }
        this.peerconnection.getStats(null,callback,errback);
    } else {
        this.peerconnection.getStats(callback);
    }
};

module.exports = TraceablePeerConnection;