diff --git a/lib/call.js b/lib/call.js
index a3492b7..3198c69 100644
--- a/lib/call.js
+++ b/lib/call.js
@@ -1,526 +1,525 @@
 'use strict';
 
 import debug from 'debug';
 import { v4 as uuidv4 } from 'uuid';
-import utils from './utils';
-
 import { EventEmitter } from 'events';
 
 import { Statistics } from './statistics';
+import utils from './utils';
 
 const DEBUG = debug('sylkrtc:Call');
 
 
 class Call extends EventEmitter {
     constructor(account) {
         super();
         this._account = account;
         this._id = null;
         this._callId = null;
         this._direction = null;
         this._pc = null;
         this._state = null;
         this._terminated = false;
         this._incomingSdp = null;
         this._remoteMediaDirections = {};
         this._localIdentity = new utils.Identity(account.id, account.displayName);
         this._remoteIdentity = null;
         this._remoteStreams = new MediaStream();
         this._localStreams = new MediaStream();
         this._previousTrack = null;
         this._sharingScreen = false;
         this._dtmfSender = null;
         this._delay_established = false;  // set to true when we need to delay posting the state change to 'established'
         this._setup_in_progress = false;  // set while we set the remote description and setup the peer copnnection
 	this._statistics = new Statistics();
 
         // bind some handlers to this instance
         this._onDtmf = this._onDtmf.bind(this);
     }
 
     get account() {
         return this._account;
     }
 
     get id() {
         return this._id;
     }
 
     get callId() {
         return this._callId;
     }
 
     get statistics() {
         return this._statistics;
     }
 
     get sharingScreen() {
         return this._sharingScreen;
     }
 
     get direction() {
         return this._direction;
     }
 
     get state() {
         return this._state;
     }
 
     get localIdentity() {
         return this._localIdentity;
     }
 
     get remoteIdentity() {
         return this._remoteIdentity;
     }
 
     get remoteMediaDirections() {
         return this._remoteMediaDirections;
     }
 
     getLocalStreams() {
         if (this._pc !== null) {
             if (this._pc.getSenders) {
                 this._pc.getSenders().forEach((e) => {
                     if (e.track != null) {
                         if (e.track.readyState !== "ended") {
                             this._localStreams.addTrack(e.track);
                         } else {
                             this._localStreams.removeTrack(e.track);
                         }
                     }
                 });
                 return [this._localStreams];
             } else {
                 return this._pc.getLocalStreams();
             }
         } else {
             return [];
         }
     }
 
     getRemoteStreams() {
         if (this._pc !== null) {
            if (this._pc.getReceivers) {
               this._pc.getReceivers().forEach((e) => {
                   if (e.track.readyState !== "ended") {
                     this._remoteStreams.addTrack(e.track);
                   }
               });
               return [this._remoteStreams];
           } else {
                 return this._pc.getRemoteStreams();
           }
         } else {
             return [];
         }
     }
 
     getSenders() {
         if (this._pc !== null) {
            return this._pc.getSenders();
         } else {
             return [];
         }
     }
 
     getReceivers() {
         if (this._pc !== null) {
            return this._pc.getReceivers();
         } else {
             return [];
         }
     }
 
     answer(options = {}) {
         if (this._state !== 'incoming') {
             throw new Error('Call is not in the incoming state: ' + this._state);
         }
 
         if (!options.localStream) {
             throw new Error('Missing localStream');
         }
 
         const pcConfig = options.pcConfig || {iceServers:[]};
         const answerOptions = options.answerOptions;
 
         // Create the RTCPeerConnection
         this._initRTCPeerConnection(pcConfig);
 
         this._pc.addStream(options.localStream);
         this.emit('localStreamAdded', options.localStream);
         this._pc.setRemoteDescription(new RTCSessionDescription({type: 'offer', sdp: this._incomingSdp}))
             // success
             .then(() => {
                 utils.createLocalSdp(this._pc, 'answer', answerOptions)
                     .then((sdp) => {
                         DEBUG('Local SDP: %s', sdp);
                         this._sendAnswer(sdp);
                     })
                     .catch((reason) => {
                         DEBUG(reason);
                         this.terminate();
                     });
             })
             // failure
             .catch((error) => {
                 DEBUG('Error setting remote description: %s', error);
                 this.terminate();
             });
     }
 
     startScreensharing(newTrack) {
         let oldTrack = this.getLocalStreams()[0].getVideoTracks()[0];
         this.replaceTrack(oldTrack, newTrack, true, (value) => {
             this._sharingScreen = value;
         });
     }
 
     stopScreensharing() {
         let oldTrack = this.getLocalStreams()[0].getVideoTracks()[0];
         this.replaceTrack(oldTrack, this._previousTrack);
         this._sharingScreen = false;
     }
 
     replaceTrack(oldTrack, newTrack, keep=false, cb=null) {
         let sender;
         for (sender of this._pc.getSenders()) {
             if (sender.track === oldTrack) {
                 break;
             }
         }
 
         sender.replaceTrack(newTrack)
             .then(() => {
                 if (keep) {
                     this._previousTrack = oldTrack;
                 } else {
                     if (oldTrack) {
                         oldTrack.stop();
                     }
                     if (newTrack === this._previousTrack) {
                         this._previousTrack = null;
                     }
                 }
 
                 if (oldTrack) {
                     this._localStreams.removeTrack(oldTrack);
                 }
                 this._localStreams.addTrack(newTrack);
 
                 if (cb) {
                     cb(true);
                 }
             }).catch((error)=> {
                 DEBUG('Error replacing track: %s', error);
             });
     }
 
     terminate() {
         if (this._terminated) {
             return;
         }
         DEBUG('Terminating call');
         this._sendTerminate();
     }
 
     sendDtmf(tones, duration=100, interToneGap=70) {
         DEBUG('sendDtmf()');
         if (this._dtmfSender === null) {
             if (this._pc !== null) {
                 let track = null;
                 try {
                     track = this._pc.getLocalStreams()[0].getAudioTracks()[0];
                 } catch (e) {
                     // ignore
                 }
                 if (track !== null) {
                     DEBUG('Creating DTMF sender');
                      if (this._pc.getSenders) {
                          this._dtmfSender = this._pc.getSenders()[0].dtmf;
                      } else {
                          DEBUG("Your browser doesn't support RTCPeerConnection.getSenders(), so " +
                              "falling back to use <strong>deprecated</strong> createDTMFSender() " +
                              "instead.");
                         this._dtmfSender = this._pc.createDTMFSender(track);
                      }
                     if (this._dtmfSender) {
                         this._dtmfSender.addEventListener('tonechange', this._onDtmf);
                     }
                 }
             }
         }
         if (this._dtmfSender) {
             DEBUG('Sending DTMF tones');
             this._dtmfSender.insertDTMF(tones, duration, interToneGap);
         }
     }
 
     // Private API
 
     _initOutgoing(uri, options={}) {
         if (uri.indexOf('@') === -1) {
             throw new Error('Invalid URI');
         }
 
         if (!options.localStream) {
             throw new Error('Missing localStream');
         }
 
         this._id = options.id || uuidv4();
         this._direction = 'outgoing';
         this._remoteIdentity = new utils.Identity(uri);
 
         const pcConfig = options.pcConfig || {iceServers:[]};
         const offerOptions = options.offerOptions;
 
         // Create the RTCPeerConnection
         this._initRTCPeerConnection(pcConfig);
 
         this._pc.addStream(options.localStream);
         this.emit('localStreamAdded', options.localStream);
         utils.createLocalSdp(this._pc, 'offer', offerOptions)
             .then((sdp) => {
                 DEBUG('Local SDP: %s', sdp);
                 this._sendCall(uri, sdp);
             })
             .catch((reason) => {
                 DEBUG(reason);
                 this._localTerminate(reason);
             });
     }
 
     _initIncoming(id, caller, sdp, callId) {
         this._id = id;
         this._remoteIdentity = new utils.Identity(caller.uri, caller.display_name);
         this._incomingSdp = sdp;
         this._direction = 'incoming';
         this._state = 'incoming';
         this._callId = callId;
         this._remoteMediaDirections = Object.assign(
             {audio: [], video:[]}, utils.getMediaDirections(sdp)
         );
         DEBUG('Remote SDP: %s', sdp);
     }
 
     _handleEvent(message) {
         DEBUG('Call event: %o', message);
         switch (message.event) {
             case 'state':
                 let oldState = this._state;
                 let newState = message.state;
                 this._state = newState;
 
                 if ((newState === 'accepted' || newState === 'early-media') && this._direction === 'outgoing') {
                     DEBUG('Call accepted or early media');
                     this.emit('stateChanged', oldState, newState, {});
                     if (message.sdp !== undefined) {
                         const sdp = utils.mungeSdp(message.sdp);
                         DEBUG('Remote SDP: %s', sdp);
                         this._remoteMediaDirections = Object.assign(
                             {audio: [], video:[]}, utils.getMediaDirections(sdp)
                         );
                         this._setup_in_progress = true;
                         this._callId = message.call_id;
                         this._pc.setRemoteDescription(new RTCSessionDescription({type: 'answer', sdp: sdp}))
                             // success
                             .then(() => {
                                 this._setup_in_progress = false;
                                 if (!this._terminated) {
                                     if (this._delay_established) {
                                         oldState = this._state;
                                         this._state = 'established';
                                         DEBUG('Setting delayed established state!');
                                         this.emit('stateChanged', oldState, this._state, {});
                                         this._delay_established = false;
                                     }
                                 }
                             })
                             // failure
                             .catch((error) => {
                                 DEBUG('Error accepting call or early media: %s', error);
                                 this.terminate();
                             });
                     }
                 } else if (newState === 'established' && this._direction === 'outgoing') {
                     if (this._setup_in_progress) {
                         this._delay_established = true;
                     } else {
                         this.emit('stateChanged', oldState, newState, {});
                     }
                 } else if (newState === 'terminated') {
                     this.emit('stateChanged', oldState, newState, {reason: message.reason});
                     this._terminated = true;
                     this._account._calls.delete(this.id);
                     this._closeRTCPeerConnection();
                 } else {
                     this.emit('stateChanged', oldState, newState, {});
                 }
                 break;
             default:
                 break;
         }
     }
 
     _initRTCPeerConnection(pcConfig) {
         if (this._pc !== null) {
             throw new Error('RTCPeerConnection already initialized');
         }
 
         this._pc = new RTCPeerConnection(pcConfig);
         this._pc.addEventListener('addstream', (event) => {
             DEBUG('Stream added');
             this.emit('streamAdded', event.stream);
         });
         this._pc.addEventListener('icecandidate', (event) => {
             if (event.candidate !== null) {
                 DEBUG('New ICE candidate %o', event.candidate);
             } else {
                 DEBUG('ICE candidate gathering finished');
             }
             this._sendTrickle(event.candidate);
         });
         this._statistics.addConnection({pc:this._pc, peerId: this._id});
     }
 
     _sendRequest(req, cb) {
         this._account._sendRequest(req, cb);
     }
 
     _sendCall(uri, sdp) {
         const req = {
             sylkrtc: 'session-create',
             account: this.account.id,
             session: this.id,
             uri: uri,
             sdp: sdp
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Call error: %s', error);
                 this._localTerminate(error);
             }
         });
     }
 
     _sendTerminate() {
         const req = {
             sylkrtc: 'session-terminate',
             session: this.id
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Error terminating call: %s', error);
                 this._localTerminate(error);
             }
         });
         setTimeout(() => {
             if (!this._terminated) {
                 DEBUG('Timeout terminating call');
                 this._localTerminate('200 OK');
             }
             this._terminated = true;
         }, 150);
     }
 
     _sendTrickle(candidate) {
         const req = {
             sylkrtc: 'session-trickle',
             session: this.id,
             candidates: candidate !== null ? [candidate] : [],
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Trickle error: %s', error);
                 this._localTerminate(error);
             }
         });
     }
 
     _sendAnswer(sdp) {
         const req = {
             sylkrtc: 'session-answer',
             session: this.id,
             sdp: sdp
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Answer error: %s', error);
                 this.terminate();
             }
         });
     }
 
     _closeRTCPeerConnection() {
         DEBUG('Closing RTCPeerConnection');
         if (this._pc !== null) {
             let tempStream;
             if (this._pc.getSenders) {
                 let tracks = [];
                 for (let track of this._pc.getSenders()) {
                     if (track.track != null ) {
                         tracks = tracks.concat(track.track);
                     }
                     if (this._previousTrack !== null) {
                         tracks = tracks.concat(this._previousTrack);
                     }
                 }
                 if (tracks.length !== 0) {
                     tempStream = new MediaStream(tracks);
                     utils.closeMediaStream(tempStream);
                 }
             } else {
                 for (let stream of this._pc.getLocalStreams()) {
                     if (this._previousTrack !== null) {
                         stream = stream.concat(this._previousTrack);
                     }
                     utils.closeMediaStream(stream);
                 }
             }
 
             if (this._pc.getReceivers) {
                 let tracks = [];
                 for (let track of this._pc.getReceivers()) {
                     tracks = tracks.concat(track.track);
                 }
                 tempStream = new MediaStream(tracks);
                 utils.closeMediaStream(tempStream);
             } else {
                 for (let stream of this._pc.getRemoteStreams()) {
                     utils.closeMediaStream(stream);
                 }
             }
             this._statistics.removeConnection({pc:this._pc, peerId: this._id});
             this._pc.close();
             this._pc = null;
             if (this._dtmfSender !== null) {
                 this._dtmfSender.removeEventListener('tonechange', this._onDtmf);
                 this._dtmfSender = null;
             }
         }
     }
 
     _localTerminate(error) {
         if (this._terminated) {
             return;
         }
         DEBUG('Local terminate');
         this._account._calls.delete(this.id);
         this._terminated = true;
         const oldState = this._state;
         const newState = 'terminated';
         const data = {
             reason: error.toString()
         };
         this._closeRTCPeerConnection();
         this.emit('stateChanged', oldState, newState, data);
     }
 
     _onDtmf(event) {
         DEBUG('Sent DTMF tone %s', event.tone);
         this.emit('dtmfToneSent', event.tone);
     }
 }
 
 
 export { Call };