jam-cloud/web/app/assets/javascripts/session.js

(function(context,$) {

    "use strict";

    context.JK = context.JK || {};
    context.JK.SessionScreen = function(app) {
        var EVENTS = context.JK.EVENTS;
        var MIX_MODES = context.JK.MIX_MODES;
        var NAMED_MESSAGES = context.JK.NAMED_MESSAGES;
        var gearUtils = context.JK.GearUtils;
        var sessionUtils = context.JK.SessionUtils;
        var modUtils = context.JK.ModUtils;
        var logger = context.JK.logger;
        var self = this;
        var sessionModel = null;
        var sessionId;
        var tracks = {};
        var myTracks = [];
        var masterMixers = [];
        var personalMixers = [];
        var allMixers = {};
        var mixersByResourceId = {};
        var mixersByTrackId = {};
        var configureTrackDialog;
        var addNewGearDialog;
        var localRecordingsDialog = null;
        var recordingFinishedDialog = null;
        var friendSelectorDialog = null;
        var inviteMusiciansUtil = null;
        var screenActive = false;
        var currentMixerRangeMin = null;
        var currentMixerRangeMax = null;
        var lookingForMixersCount = 0;
        var lookingForMixersTimer = null;
        var lookingForMixers = [];
        var $recordingTimer = null;
        var recordingTimerInterval = null;
        var startTimeDate = null;
        var startingRecording = false; // double-click guard
        var claimedRecording = null;
        var playbackControls = null;
        var promptLeave = false;
        var rateSessionDialog = null;
        var friendInput = null;
        var sessionPageDone = null;
        var $recordingManagerViewer = null;
        var $screen = null;
        var $mixModeDropdown = null;
        var $templateMixerModeChange = null;

        var rest = context.JK.Rest();
        var RENDER_SESSION_DELAY = 750;  // When I need to render a session, I have to wait a bit for the mixers to be there.

        var defaultParticipant = {
            tracks: [{
                instrument_id: "unknown"
            }],
            user: {
                first_name: 'Unknown',
                last_name: 'User',
                photo_url: null
            }
        };

        // Be sure to copy/extend these instead of modifying in place
        var trackVuOpts = {
            vuType: "vertical",
            lightCount: 13,
            lightWidth: 3,
            lightHeight: 17
        };
        // Must add faderId key to this
        var trackFaderOpts = {
            faderType: "vertical",
            height: 83
        };

        // Recreate ChannelGroupIDs ENUM from C++
        var ChannelGroupIds = {
            "MasterGroup": 0,
            "MonitorGroup": 1,
            "AudioInputMusicGroup": 2,
            "AudioInputChatGroup": 3,
            "MediaTrackGroup": 4,
            "StreamOutMusicGroup": 5,
            "StreamOutChatGroup": 6,
            "UserMusicInputGroup": 7,
            "UserChatInputGroup": 8,
            "PeerAudioInputMusicGroup": 9,
            "PeerMediaTrackGroup": 10
        };

        function beforeShow(data) {
            sessionId = data.id;
            if(!sessionId) {
              window.location = '/client#/home';
            }
            promptLeave = true;
            $('#session-mytracks-container').empty();
            displayDoneRecording(); // assumption is that you can't join a recording session, so this should be safe

            var shareDialog = new JK.ShareDialog(context.JK.app, sessionId, "session");
            shareDialog.initialize(context.JK.FacebookHelperInstance);
        }

        function beforeDisconnect() {
          return { freezeInteraction: true };
        }

        function initializeSession() {

          // Subscribe for callbacks on audio events
          context.jamClient.SessionRegisterCallback("JK.HandleBridgeCallback");
          context.jamClient.RegisterRecordingCallbacks("JK.HandleRecordingStartResult", "JK.HandleRecordingStopResult", "JK.HandleRecordingStarted", "JK.HandleRecordingStopped", "JK.HandleRecordingAborted");
          context.jamClient.SessionSetConnectionStatusRefreshRate(1000);

          // If you load this page directly, the loading of the current user
          // is happening in parallel. We can't join the session until the
          // current user has been completely loaded. Poll for the current user
          // before proceeding with session joining.
          function checkForCurrentUser() {
            if (context.JK.userMe) {
              afterCurrentUserLoaded();
            } else {
              context.setTimeout(checkForCurrentUser, 100);
            }
          }
          checkForCurrentUser();
        }

        function afterShow(data) {

          if(!context.JK.JamServer.connected) {
            promptLeave = false;
            app.notifyAlert("Not Connected", 'To create or join a session, you must be connected to the server.');
            window.location = '/client#/home'
            return;
          }

          // The SessionModel is a singleton.
          // a client can only be in one session at a time,
          // and other parts of the code want to know at any certain times
          // about the current session, if any (for example, reconnect logic)
          if(context.JK.CurrentSessionModel) {
            context.JK.CurrentSessionModel.ensureEnded();
          }

          context.JK.CurrentSessionModel = sessionModel = new context.JK.SessionModel(
            context.JK.app,
            context.JK.JamServer,
            context.jamClient,
            self
          );

          sessionModel.start(sessionId);
          // indicate that the screen is active, so that
          // body-scoped drag handlers can go active
          screenActive = true;

          gearUtils.guardAgainstInvalidConfiguration(app)
            .fail(function() {
              promptLeave = false;
              window.location = '/client#/home'
            })
            .done(function(){
              var result = sessionUtils.SessionPageEnter();

              gearUtils.guardAgainstActiveProfileMissing(app, result)
                .fail(function(data) {
                  promptLeave = false;
                  if(data && data.reason == 'handled') {
                    if(data.nav == 'BACK') {
                      window.history.go(-1);
                    }
                    else {
                      window.location = data.nav;
                    }
                  }
                  else {
                    window.location = '/client#/home';
                  }
                })
                .done(function(){

                  sessionModel.waitForSessionPageEnterDone()
                    .done(function(userTracks) {

                      context.JK.CurrentSessionModel.setUserTracks(userTracks);

                      initializeSession();
                    })
                    .fail(function(data) {
                      if(data == "timeout") {
                        context.JK.alertSupportedNeeded('The audio system has not reported your configured tracks in a timely fashion.')
                      }
                      else if(data == 'session_over') {
                        // do nothing; session ended before we got the user track  info. just bail
                      }
                      else {
                        contetx.JK.alertSupportedNeeded('Unable to determine configured tracks due to reason: ' + data)
                      }
                      promptLeave = false;
                      window.location = '/client#/home'
                    });

                })

            })


        }

        function notifyWithUserInfo(title , text, clientId) {
            sessionModel.findUserBy({clientId: clientId})
                .done(function(user) {
                    app.notify({
                        "title": title,
                        "text": user.name + " " + text,
                        "icon_url": context.JK.resolveAvatarUrl(user.photo_url)
                    });
                })
                .fail(function() {
                    app.notify({
                        "title": title,
                        "text": 'Someone ' + text,
                        "icon_url": "/assets/content/icon_alert_big.png"
                    });
                });
        }


        function afterCurrentUserLoaded() {
            var sessionModel = context.JK.CurrentSessionModel;

            $(sessionModel.recordingModel)
                .on('startingRecording', function(e, data) {
                    displayStartingRecording();
                })
                .on('startedRecording', function(e, data) {
                    if(data.reason) {
                        var reason = data.reason;
                        var detail = data.detail;

                        var title = "Could Not Start Recording";

                        if(data.reason == 'client-no-response') {
                            notifyWithUserInfo(title, 'did not respond to the start signal.', detail);
                        }
                        else if(data.reason == 'empty-recording-id') {
                            app.notifyAlert(title, "No recording ID specified.");
                        }
                        else if(data.reason == 'missing-client') {
                            notifyWithUserInfo(title, 'could not be signalled to start recording.', detail);
                        }
                        else if(data.reason == 'already-recording') {
                            app.notifyAlert(title, 'Already recording. If this appears incorrect, try restarting JamKazam.');
                        }
                        else if(data.reason == 'recording-engine-unspecified') {
                            notifyWithUserInfo(title, 'had a problem writing recording data to disk.', detail);
                        }
                        else if(data.reason == 'recording-engine-create-directory') {
                            notifyWithUserInfo(title, 'had a problem creating a recording folder.', detail);
                        }
                        else if(data.reason == 'recording-engine-create-file') {
                            notifyWithUserInfo(title, 'had a problem creating a recording file.', detail);
                        }
                        else if(data.reason == 'recording-engine-sample-rate') {
                            notifyWithUserInfo(title, 'had a problem recording at the specified sample rate.', detail);
                        }
                        else if(data.reason == 'rest') {
                            var jqXHR = detail[0];
                            app.notifyServerError(jqXHR);
                        }
                        else {
                            notifyWithUserInfo(title, 'Error Reason: ' + reason);
                        }
                        displayDoneRecording();
                    }
                    else
                    {
                        displayStartedRecording();
                        displayWhoCreated(data.clientId);
                    }
                })
                .on('stoppingRecording', function(e, data) {
                    displayStoppingRecording(data);
                })
                .on('stoppedRecording', function(e, data) {
                    if(data.reason) {
                      logger.warn("Recording Discarded: ", data);
                        var reason = data.reason;
                        var detail = data.detail;

                        var title = "Recording Discarded";

                        if(data.reason == 'client-no-response') {
                            notifyWithUserInfo(title, 'did not respond to the stop signal.', detail);
                        }
                        else if(data.reason == 'missing-client') {
                            notifyWithUserInfo(title, 'could not be signalled to stop recording.', detail);
                        }
                        else if(data.reason == 'empty-recording-id') {
                            app.notifyAlert(title, "No recording ID specified.");
                        }
                        else if(data.reason == 'wrong-recording-id') {
                            app.notifyAlert(title, "Wrong recording ID specified.");
                        }
                        else if(data.reason == 'not-recording') {
                            app.notifyAlert(title, "Not currently recording.");
                        }
                        else if(data.reason == 'already-stopping') {
                            app.notifyAlert(title, "Already stopping the current recording.");
                        }
                        else if(data.reason == 'start-before-stop') {
                            notifyWithUserInfo(title, 'asked that we start a new recording; cancelling the current one.', detail);
                        }
                        else {
                            app.notifyAlert(title, "Error reason: " + reason);
                        }

                        displayDoneRecording();
                    }
                    else {
                        displayDoneRecording();
                        promptUserToSave(data.recordingId);
                    }

                })
                .on('abortedRecording', function(e, data) {
                    var reason = data.reason;
                    var detail = data.detail;

                    var title = "Recording Cancelled";

                    if(data.reason == 'client-no-response') {
                        notifyWithUserInfo(title, 'did not respond to the start signal.', detail);
                    }
                    else if(data.reason == 'missing-client') {
                        notifyWithUserInfo(title, 'could not be signalled to start recording.', detail);
                    }
                    else if(data.reason == 'populate-recording-info') {
                        notifyWithUserInfo(title, 'could not synchronize with the server.', detail);
                    }
                    else if(data.reason == 'recording-engine-unspecified') {
                        notifyWithUserInfo(title, 'had a problem writing recording data to disk.', detail);
                    }
                    else if(data.reason == 'recording-engine-create-directory') {
                        notifyWithUserInfo(title, 'had a problem creating a recording folder.', detail);
                    }
                    else if(data.reason == 'recording-engine-create-file') {
                        notifyWithUserInfo(title, 'had a problem creating a recording file.', detail);
                    }
                    else if(data.reason == 'recording-engine-sample-rate') {
                        notifyWithUserInfo(title, 'had a problem recording at the specified sample rate.', detail);
                    }
                    else {
                        app.notifyAlert(title, "Error reason: " + reason);
                    }

                    displayDoneRecording();

                })

            sessionModel.subscribe('sessionScreen', sessionChanged);
            sessionModel.joinSession(sessionId)
                .fail(function(xhr, textStatus, errorMessage) {
                    if(xhr.status == 404) {
                        // we tried to join the session, but it's already gone.  kick user back to join session screen
                        promptLeave = false;
                        context.window.location = "/client#/findSession";
                        app.notify(
                            {   title: "Unable to Join Session",
                                text: "The session you attempted to join is over."
                            },
                            null,
                            true);
                    }
                    else if(xhr.status == 422) {
                      var response = JSON.parse(xhr.responseText);
                      if(response["errors"] && response["errors"]["tracks"] && response["errors"]["tracks"][0] == "Please select at least one track") {
                        app.notifyAlert("No Inputs Configured", $('<span>You will need to reconfigure your audio device.</span>'));
                      }
                      else if(response["errors"] && response["errors"]["music_session"] && response["errors"]["music_session"][0] == ["is currently recording"]) {
                        promptLeave = false;
                        context.window.location = "/client#/findSession";
                        app.notify( { title: "Unable to Join Session", text: "The session is currently recording." }, null, true);
                      }
                      else {
                        app.notifyServerError(xhr, 'Unable to Join Session');
                      }
                    }
                    else {
                        app.notifyServerError(xhr, 'Unable to Join Session');
                    }
                });
        }

        // not leave session but leave screen
        function beforeLeave(data) {
          if(promptLeave) {
            var leaveSessionWarningDialog = new context.JK.LeaveSessionWarningDialog(context.JK.app,
              function() {  promptLeave = false; context.location.hash = data.hash });

            leaveSessionWarningDialog.initialize();
            app.layout.showDialog('leave-session-warning');
            return false;
          }
          return true;
        }

       function beforeHide(data) {

           if(screenActive) {
             // this path is possible if FTUE is invoked on session page, and they cancel
             sessionModel.leaveCurrentSession()
               .fail(function(jqXHR) {
                 if(jqXHR.status != 404) {
                   logger.debug("leave session failed");
                   app.ajaxError(arguments)
                 }
               });
           }
          screenActive = false;

          sessionUtils.SessionPageLeave();
        }

        function handleTransitionsInRecordingPlayback() {
            // let's see if we detect a transition to start playback or stop playback

            var currentSession = sessionModel.getCurrentSession();

            if(claimedRecording == null  && (currentSession && currentSession.claimed_recording != null)) {
                // this is a 'started with a claimed_recording' transition.
                // we need to start a timer to watch for the state of the play session
                playbackControls.startMonitor();
            }
            else if(claimedRecording && (currentSession == null || currentSession.claimed_recording == null)) {
                playbackControls.stopMonitor();
            }

            claimedRecording = currentSession == null ? null : currentSession.claimed_recording;

        }
        function sessionChanged() {

            handleTransitionsInRecordingPlayback();
            // TODO - in the specific case of a user changing their tracks using the configureTrack dialog,
            // this event appears to fire before the underlying mixers have updated. I have no event to
            // know definitively when the underlying mixers are up to date, so for now, we just delay slightly.
            // This obviously has the possibility of introducing time-based bugs.
            context.setTimeout(renderSession, RENDER_SESSION_DELAY);
        }

        /**
        * the mixers object is a list. In order to find one by key,
        * you must iterate. Convenience method to locate a particular
        * mixer by id.
        */
        function getMixer(mixerId) {
            return allMixers[mixerId];
        }

        function getMixerByResourceId(resourceId, mode) {
          var mixerPair = mixersByResourceId[resourceId];

          if(!mixerPair) {return null;}

          if(mode === undefined) {
            return mixerPair;
          }
          else {
            if(mode == MIX_MODES.MASTER) {
              return mixerPair.master;
            }
            else {
              return mixerPair.personal;
            }
          }
        }

        function getMixerByTrackId(trackId, mode) {
          var mixerPair = mixersByTrackId[trackId];

          if(!mixerPair) {return null;}

          if(mode === undefined) {
            return mixerPair;
          }
          else {
            if(mode == MIX_MODES.MASTER) {
              return mixerPair.master;
            }
            else {
              return mixerPair.personal;
            }
          }
        }

        function renderSession() {
            $('#session-mytracks-container').empty();
            $('.session-track').remove(); // Remove previous tracks
            var $voiceChat = $('#voice-chat');
            $voiceChat.hide();
            _updateMixers();
            _renderTracks();
            _renderLocalMediaTracks();
            _wireTopVolume();
            _wireTopMix();
            _addVoiceChat();
            _initDialogs();
            if ($('.session-livetracks .track').length === 0) {
                $('.session-livetracks .when-empty').show();
            }
            if ($('.session-recordings .track').length === 0) {
                $('.session-recordings .when-empty').show();
                $('.session-recording-name-wrapper').hide();
                $('.session-recordings .recording-controls').hide();
            }
        }

        function _initDialogs() {
            configureTrackDialog.initialize();
            addNewGearDialog.initialize();
        }

        // Get the latest list of underlying audio mixer channels, and populates:
        // * mixersByResourceId  - a hash of resourceId / { master: mixer, personal: mixer }   personal: can be null in case of PeerAudioInputMusicGroup
        // * mixersByTrackId - a hash of track id / {master: mixer, personal: mixer}.
        // * allMixers - a hash of mixer.id / mixer
        // * masterMixers - array of master mode mixers
        // * personalMixers - array of personal mode mixers
        function _updateMixers() {
            masterMixers = context.jamClient.SessionGetAllControlState(true);
            personalMixers = context.jamClient.SessionGetAllControlState(false);

            //logger.debug("masterMixers", masterMixers)
            //logger.debug("personalMixers", personalMixers)

            mixersByResourceId = {}
            mixersByTrackId = {}
            allMixers = {}

            var i;
            for(i = 0; i < masterMixers.length; i++) {
              var masterMixer = masterMixers[i];
              allMixers[masterMixer.id] = masterMixer; // populate allMixers by mixer.id

              // populate mixer pair
              var  mixerPair = {}
              mixersByResourceId[masterMixer.rid] = mixerPair
              mixersByTrackId[masterMixer.id] = mixerPair
              mixerPair.master = masterMixer;
            }
            for(i = 0; i < personalMixers.length; i++) {
              var personalMixer = personalMixers[i];

              if(personalMixer.group_id == ChannelGroupIds.MediaTrackGroup) {
                continue;
              }

              allMixers[personalMixer.id] = personalMixer

              // populate other side of mixer pair

              var mixerPair = mixersByResourceId[personalMixer.rid]
              if(!mixerPair) {
                if(personalMixer.group_id != ChannelGroupIds.MonitorGroup) {
                  logger.warn("there is no master version of ", personalMixer)
                }

                mixerPair = {}
                mixersByResourceId[personalMixer.rid] = mixerPair
              }
              mixersByTrackId[personalMixer.id] = mixerPair;

              mixerPair.personal = personalMixer;
            }
            // Always add a hard-coded simplified 'mixer' for the L2M mix

            /**
            var l2m_mixer = {
                  id: '__L2M__',
                  range_low: -80,
                  range_high: 20,
                  volume_left: context.jamClient.SessionGetMasterLocalMix()
              };
              mixers.push(l2m_mixer);*/
        }

        function _mixersForGroupId(groupId, mixMode) {
            var foundMixers = [];
            var mixers = mixMode == MIX_MODES.MASTER ? masterMixers : personalMixers;
            $.each(mixers, function(index, mixer) {
                if ( mixer.group_id === groupId) {
                    foundMixers.push(mixer);
                }
            });
            return foundMixers;
        }

        function _getMyVoiceChatMixers() {
          var mixers = _mixersForGroupId(ChannelGroupIds.AudioInputChatGroup, sessionModel.getMixMode());

          if (mixers.length == 0) { return null; }

          var oppositeMixers = _mixersForGroupId(ChannelGroupIds.AudioInputChatGroup, !sessionModel.getMixMode());

          if(oppositeMixers.length == 0) {
            logger.warn("unable to find opposite mixer for voice chat");
            return null;
          }

          var mixer = mixers[0];
          var oppositeMixer = oppositeMixers[0];

          return {
            mixer: mixer,
            oppositeMixer: oppositeMixer,
            vuMixer: mixer,
            muteMixer: mixer
          }
        }

        function _clientIdForUserInputMixer(mixerId, mixMode) {
          var found = null;
          var mixers = mixMode == MIX_MODES.MASTER ? masterMixers : personalMixers;
          $.each(mixers, function(index, mixer) {
            if (mixer.group_id === ChannelGroupIds.UserMusicInputGroup && mixer.id == mixerId) {
              found = mixer.client_id;
              return false;
            }
          });
          return found;
        }

        // TODO FIXME - This needs to support multiple tracks for an individual
        // client id and group.
        function _mixerForClientId(clientId, groupIds, usedMixers) {
            //logger.debug("clientId", clientId, "groupIds", groupIds, "mixers", mixers)
            var foundMixer = null;
            $.each(mixers, function(index, mixer) {
                if (mixer.client_id === clientId) {
                    for (var i=0; i<groupIds.length; i++) {
                        if (mixer.group_id === groupIds[i]) {
                            if (!(mixer.id in usedMixers)) {
                                foundMixer = mixer;
                                return false;
                            }
                        }
                    }
                }
            });
            return foundMixer;
        }

        function _groupedMixersForClientId(clientId, groupIds, usedMixers, mixMode) {
          //logger.debug("clientId", clientId, "groupIds", groupIds, "mixers", mixers)
          var foundMixers = {};
          var mixers = mixMode == MIX_MODES.MASTER ? masterMixers : personalMixers;
         // console.log("_groupedMixersForClientId", mixers)
          $.each(mixers, function(index, mixer) {
            if (mixer.client_id === clientId) {
              for (var i=0; i<groupIds.length; i++) {
                if (mixer.group_id === groupIds[i]) {
                  if ((mixer.groupId != ChannelGroupIds.UserMusicInputGroup) && !(mixer.id in usedMixers)) {
                    var mixers = foundMixers[mixer.group_id]
                    if(!mixers) {
                      mixers = []
                      foundMixers[mixer.group_id] = mixers;
                    }
                    mixers.push(mixer)
                  }
                }
              }
            }
          });
          return foundMixers;
        }

        function _wireTopVolume() {
            var gainPercent = 0;
            var mixerIds = [];
            var mixers = sessionModel.isMasterMixMode() ? masterMixers : personalMixers;
            $.each(mixers, function(index, mixer) {
                if (sessionModel.isMasterMixMode() && mixer.group_id === ChannelGroupIds.MasterGroup) {
                    mixerIds.push(mixer.id);
                    gainPercent = percentFromMixerValue(
                        mixer.range_low, mixer.range_high, mixer.volume_left);
                }
                else if (!sessionModel.isMasterMixMode() && mixer.group_id === ChannelGroupIds.MonitorGroup) {
                    mixerIds.push(mixer.id);
                    gainPercent = percentFromMixerValue(
                    mixer.range_low, mixer.range_high, mixer.volume_left);
                }
            });
            if(mixerIds.length == 0) {
              logger.debug("did not find master/monitor volume", mixers)

            }

            var faderId = mixerIds.join(',');
            var $volume = $('#volume');
            $volume.attr('mixer-id', faderId);
            var faderOpts = {
                faderId: faderId,
                faderType: "horizontal",
                width: 50,
                style: {
                    "background-image": "none",
                    "background-repeat":"no-repeat",
                    "height": "24px"
                }
            };
            context.JK.FaderHelpers.renderFader($volume, faderOpts);

            $volume.on('fader_change', faderChanged);
            // Visually update fader to underlying mixer start value.
            // Always do this, even if gainPercent is zero.

            context.JK.FaderHelpers.setFaderValue(faderId, gainPercent);
        }

        /**
        * This control has it's own Set/Get methods, so we don't need to
        * line it up with some mixer later. We'll use a special mixer-id value
        * to let us know we're dealing with the mix control.
        */
        function _wireTopMix() {
            var $mixSlider = $('#l2m');
            var l2m_mixer = {
                range_low: -80,
                range_high: 20,
                volume_left: context.jamClient.SessionGetMasterLocalMix()
            };
            // var gainPercent = percentFromMixerValue(
            //     l2m_mixer.range_low, l2m_mixer.range_high, l2m_mixer.volume_left);

            var faderId = '#l2m'; // also the selector for renderFader

            var faderOpts = {
                faderId: faderId,
                faderType: "horizontal",
                width: 70,
                style: {
                    "background-image": "none",
                    "background-repeat":"no-repeat",
                    "height": "24px"
                }
            };
            context.JK.FaderHelpers.renderFader($mixSlider, faderOpts);
            $mixSlider.on('fader_change', l2mChanged);

            var value = context.jamClient.SessionGetMasterLocalMix();
            context.JK.FaderHelpers.setFaderValue(faderId, percentFromMixerValue(-80, 20, value));
        }

        /**
        * This has a specialized jamClient call, so custom handler.
        */
        function l2mChanged(e, data) {
            //var dbValue = context.JK.FaderHelpers.convertLinearToDb(newValue);
            context.jamClient.SessionSetMasterLocalMix(data.percentage - 80);
        }

        function _addVoiceChat() {
            // If, and only if, there is a mixer in group 3 (voice chat)
            // Add the voice chat controls below my tracks, and hook up the mixer.
            // Assumption is that there is only ever one, so we just take the first one.
            var voiceChatMixers = _getMyVoiceChatMixers();

            if(voiceChatMixers) {
              var mixer = voiceChatMixers.mixer;

              var $voiceChat = $('#voice-chat');
              $voiceChat.show();
              $voiceChat.attr('mixer-id', mixer.id);
              var $voiceChatGain = $voiceChat.find('.voicechat-gain');
              $voiceChatGain.attr('mixer-id', mixer.id);
              var $voiceChatMute = $voiceChat.find('.voicechat-mute').attr('mixer-id', mixer.id).data('mixer', mixer).data('opposite-mixer', voiceChatMixers.oppositeMixer)
              var gainPercent = percentFromMixerValue(
                mixer.range_low, mixer.range_high, mixer.volume_left);
              var faderOpts = {
                faderId: mixer.id,
                faderType: "horizontal",
                width: 50
              };
              context.JK.FaderHelpers.renderFader($voiceChatGain, faderOpts);
              $voiceChatGain.on('fader_change', faderChanged);
              context.JK.FaderHelpers.setFaderValue(mixer.id, gainPercent);
              if (mixer.mute) {
                _toggleVisualMuteControl($voiceChatMute, mixer.mute);
              }
            }
        }

        function _renderLocalMediaTracks() {

          // first gather all master mode media mixers and peer media mixers
          var localMediaMixers = _mixersForGroupId(ChannelGroupIds.MediaTrackGroup, MIX_MODES.MASTER);
          var peerLocalMediaMixers = _mixersForGroupId(ChannelGroupIds.PeerMediaTrackGroup, MIX_MODES.MASTER);

          // with mixer info, we use these to decide what kind of tracks are open in the backend

          // each mixer has a media_type field, which describes the type of media track it is.
          // * JamTrack
          // * BackingTrack
          // * RecordingTrack
          // * MetronomeTrack
          // * "" - adhoc track (not supported visually)

          // it is supposed to be the case that there are only one type of track open at a time, however, that's a business policy/logic
          // constraint; and may be buggy. **So, we should render whatever we have, so that it's obvious what's really going on.**

          // so, let's group up all mixers by type, and then ask them to be rendered

          var recordingTrackMixers = [];
          var backingTrackMixers = [];
          var jamTrackMixers = [];
          var metronomeTrackMixers = [];
          var adhocTrackMixers = [];


          function groupByType(mixers) {
            context._.each(mixers, function(mixer) {
              var mediaType = mixer.media_type;

              if(mediaType == 'RecordingTrack') {
                recordingTrackMixers.push(mixer)
              }
              else if(mediaType == 'BackingTrack') {
                backingTrackMixers.push(mixer);
              }
              else if(mediaType == 'MetronomeTrack') {
                metronomeTrackMixers.push(mixer);
              }
              else if(mediaType == 'JamTrack') {
                jamTrackMixers.push(mixer);
              }
              else {
                adhocTrackMixers.push(mixer);
              }
            });
          }

          groupByType(localMediaMixers);
          groupByType(peerLocalMediaMixers);

          if(recordingTrackMixers.length > 0) {
            renderRecordingTracks(recordingTrackMixers)
          }
          if(backingTrackMixers.length > 0) {
            renderBackingTracks(backingTrackMixers)
          }
          if(jamTrackMixers.length > 0) {
            renderJamTracks(jamTrackMixers);
          }
          if(metronomeTrackMixers.length > 0) {
            renderMetronomeTracks(jamTrackMixers);
          }
          if(adhocTrackMixers.length > 0) {
            logger.warn("some tracks are open that we don't know how to show")
          }
        }


        function renderBackingTracks(backingTrackMixers) {
          logger.error("do not know how to draw backing tracks yet")
        }

        function renderJamTracks(jamTrackMixers) {
          logger.error("do not know how to draw jam tracks yet")
        }

        function renderMetronomeTracks(metronomeTrackMixers) {
          logger.error("do not know how to draw metronome tracks yet")
        }


        function renderRecordingTracks(recordingMixers) {
          // get the server's info for the recording
          var recordedTracks = sessionModel.recordedTracks();

          if(recordedTracks && recordingMixers.length == 0) {
            // if we are the creator, then rather than raise an error, tell the server the recording is over.
            // this shoudl only happen if we get temporarily disconnected by forced reload, which isn't a very normal scenario
            if(sessionModel.getCurrentSession().claimed_recording_initiator_id == context.JK.userMe.id) {
              closeRecording();
              return;
            }
          }

          // pluck the 1st mixer, and assume that all other mixers in this group are of the same type (between Local vs Peer)
          // if it's a locally opened track (MediaTrackGroup), then we can say this person is the opener

          var isOpener = recordingMixers[0].group_id == ChannelGroupIds.MediaTrackGroup;

          // using the server's info in conjuction with the client's, draw the recording tracks
          if(recordedTracks) {
            $('.session-recording-name').text(sessionModel.getCurrentSession().claimed_recording.name);

            var noCorrespondingTracks = false;
            $.each(recordingMixers, function(index, mixer) {
              var preMasteredClass = "";
              // find the track or tracks that correspond to the mixer
              var correspondingTracks = []
              $.each(recordedTracks, function(i, recordedTrack) {
                if(mixer.id.indexOf("L") == 0) {
                  if(mixer.id.substring(1) == recordedTrack.client_track_id) {
                    correspondingTracks.push(recordedTrack);
                  }
                }
                else if(mixer.id.indexOf("C") == 0) {
                  if(mixer.id.substring(1) == recordedTrack.client_id) {
                    correspondingTracks.push(recordedTrack);
                    preMasteredClass = "pre-mastered-track";
                  }
                }
                else {
                  // this should not be possible
                  alert("Invalid state: the recorded track had neither persisted_track_id or persisted_client_id");
                }
              });

              if(correspondingTracks.length == 0) {
                noCorrespondingTracks = true;
                app.notify({
                  title: "Unable to Open Recording",
                  text: "Could not correlate server and client tracks",
                  icon_url: "/assets/content/icon_alert_big.png"});
                return false;
              }

              // prune found recorded tracks
              recordedTracks = $.grep(recordedTracks, function(value) {
                return $.inArray(value, correspondingTracks) < 0;
              });

              var oneOfTheTracks = correspondingTracks[0];
              var instrumentIcon = context.JK.getInstrumentIcon45(oneOfTheTracks.instrument_id);
              var photoUrl = "/assets/content/icon_recording.png";

              var name = oneOfTheTracks.user.name;
              if (!(name)) {
                name = oneOfTheTracks.user.first_name + ' ' + oneOfTheTracks.user.last_name;
              }

              // Default trackData to participant + no Mixer state.
              var trackData = {
                trackId: oneOfTheTracks.id,
                clientId: oneOfTheTracks.client_id,
                name: name,
                instrumentIcon: instrumentIcon,
                avatar: photoUrl,
                latency: "good",
                gainPercent: 0,
                muteClass: 'muted',
                mixerId: "",
                avatarClass : 'avatar-recording',
                preMasteredClass: preMasteredClass
              };

              var gainPercent = percentFromMixerValue(
                mixer.range_low, mixer.range_high, mixer.volume_left);
              var muteClass = "enabled";
              if (mixer.mute) {
                muteClass = "muted";
              }
              trackData.gainPercent = gainPercent;
              trackData.muteClass = muteClass;
              trackData.mixerId = mixer.id; // the master mixer controls the volume control for recordings (no personal controls in either master or personal mode)
              trackData.vuMixerId = mixer.id; // the master mixer controls the VUs for recordings (no personal controls in either master or personal mode)
              trackData.muteMixerId = mixer.id; // the master mixer controls the mute for recordings (no personal controls in either master or personal mode)

              if(sessionModel.isPersonalMixMode() || !isOpener) {
                trackData.mediaControlsDisabled = true;
                trackData.mediaTrackOpener = isOpener;
              }
              _addRecordingTrack(trackData);
            });

            if(!noCorrespondingTracks && recordedTracks.length > 0) {
              logger.error("unable to find all recorded tracks against client tracks");
              app.notify({title:"All tracks not found",
                text: "Some tracks in the recording are not present in the playback",
                icon_url: "/assets/content/icon_alert_big.png"})
            }
          }
        }

        function trackMuteSelected(e, data) {
          var muteOption = data.muteOption; // muteOption is going to be either 'master' or 'personal'.  We mute the correct one, based on track info

          var $muteControl = $(this);

          // mixer is the mixer object returned from the backend corresponding to the mixer in this particular mode
          // oppositeMixer is the mixer correspond to the opposite mode.
          // Note that oppositeMixer is not ever set for ChannelGroupIds.AudioInputMusicGroup or ChannelGroupIds.MediaTrackGroup

          var mixer = $muteControl.data('mixer')
          var oppositeMixer = $muteControl.data('opposite-mixer')


          logger.debug("muting tracks. current mixer id=" + mixer.id + ", opposite mixer id=" + oppositeMixer.id)

          var mixerPair = {}
          if(sessionModel.isMasterMixMode()) {
            mixerPair.master = mixer;
            mixerPair.personal = oppositeMixer;
          }
          else {
            mixerPair.master = oppositeMixer;
            mixerPair.personal = mixer;
          }
          if(muteOption == 'master') {
            _toggleAudioMute(mixerPair.master.id, true, mixerPair.master.mode);
            _toggleAudioMute(mixerPair.personal.id, true, mixerPair.personal.mode);
          }
          else {
            _toggleAudioMute(mixerPair.personal.id, true, mixerPair.personal.mode);
            _toggleAudioMute(mixerPair.master.id, false, mixerPair.master.mode);
          }

          _toggleVisualMuteControl($muteControl, true);
        }

        // find backend mixer based on track data, and target client_id
        function findMixerForTrack(client_id, track, myTrack) {
          var mixer = null; // what is the best mixer for this track/client ID?
          var oppositeMixer = null; // what is the corresponding mixer in the opposite mode?
          var vuMixer = null;
          var muteMixer = null;

          var mixMode = sessionModel.getMixMode();
          if(myTrack) {
            // when it's your track, look it up by the backend resource ID
            mixer = getMixerByTrackId(track.client_track_id, mixMode)
            vuMixer = mixer;
            muteMixer = mixer;

            // sanity checks
            if(mixer && (mixer.group_id != ChannelGroupIds.AudioInputMusicGroup)) { logger.error("found local mixer that was not of groupID: AudioInputMusicGroup", mixer) }

            if(mixer) {
              // find the matching AudioInputMusicGroup for the opposite mode
              oppositeMixer = getMixerByTrackId(track.client_track_id, !mixMode)

              if(mixMode == MIX_MODES.PERSONAL) {
                muteMixer = oppositeMixer; // make the master mixer the mute mixer
              }

              // sanity checks
              if(!oppositeMixer) {logger.error("unable to find opposite mixer for local mixer", mixer)}
              else if(oppositeMixer.group_id != ChannelGroupIds.AudioInputMusicGroup) { logger.error("found local mixer in opposite mode that was not of groupID: AudioInputMusicGroup", mixer, oppositeMixer)}
            }
            else {
              logger.debug("local track is not present: ", track)
            }
          }
          else {
            if(mixMode === MIX_MODES.MASTER) {

              // when it's a remote track and in master mode, we should find the PeerAudioInputMusicGroup
              mixer = getMixerByTrackId(track.client_track_id, MIX_MODES.MASTER)
              if(mixer && (mixer.group_id != ChannelGroupIds.PeerAudioInputMusicGroup)) { logger.error("found remote mixer that was not of groupID: PeerAudioInputMusicGroup", mixer) }

              vuMixer = mixer;
              muteMixer = mixer;

              if(mixer) {
                // we should be able to find a UserMusicInputGroup for this clientId in personal mode
                var oppositeMixers  = _groupedMixersForClientId(client_id, [ ChannelGroupIds.UserMusicInputGroup], {}, MIX_MODES.PERSONAL);
                if (oppositeMixers[ChannelGroupIds.UserMusicInputGroup]) { oppositeMixer = oppositeMixers[ChannelGroupIds.UserMusicInputGroup][0]; }

                if(!oppositeMixer) {logger.error("unable to find UserMusicInputGroup corresponding to PeerAudioInputMusicGroup mixer", mixer ) }
              }
            }
            else {
              // when it's a remote track and in personal mode, we want the 'Peer Stream', which is UserMusicInputGroup
              // this spans N tracks for the remote user
              var mixers  = _groupedMixersForClientId(client_id, [ ChannelGroupIds.UserMusicInputGroup], {}, MIX_MODES.PERSONAL);
              if (mixers[ChannelGroupIds.UserMusicInputGroup]) { mixer = mixers[ChannelGroupIds.UserMusicInputGroup][0]; }

              vuMixer = mixer;
              muteMixer = mixer;

              if(mixer) {
                // now grab the PeerAudioInputMusicGroup in master mode to satisfy the 'opposite' mixer
                oppositeMixer = getMixerByTrackId(track.client_track_id, MIX_MODES.MASTER)
                if(!oppositeMixer) {logger.debug("unable to find a PeerAudioInputMusicGroup master mixer matching a UserMusicInput", track.client_track_id, mixersByTrackId)}
                else if(oppositeMixer.group_id != ChannelGroupIds.PeerAudioInputMusicGroup) { logger.error("found remote mixer that was not of groupID: PeerAudioInputMusicGroup", mixer) }

                vuMixer = oppositeMixer; // for personal mode, use the PeerAudioInputMusicGroup's VUs
              }
            }
          }


          return {
            mixer: mixer,
            oppositeMixer: oppositeMixer,
            vuMixer: vuMixer,
            muteMixer: muteMixer
          }
        }
        function _renderTracks() {
            myTracks = [];

            // Participants are here now, but the mixers don't update right away.
            // Draw tracks from participants, then setup timers to look for the
            // mixers that go with those participants, if they're missing.

            lookingForMixers = []  // clear this back out as we are restarting from scratch
            lookingForMixersCount = 0;
            $.each(sessionModel.participants(), function(index, participant) {

                var name = participant.user.name;
                if (!(name)) {
                    name = participant.user.first_name + ' ' + participant.user.last_name;
                }

                var myTrack = app.clientId == participant.client_id;

                // loop through all tracks for each participant
                $.each(participant.tracks, function(index, track) {
                    var instrumentIcon = context.JK.getInstrumentIcon45(track.instrument_id);
                    var photoUrl = context.JK.resolveAvatarUrl(participant.user.photo_url);

                    // Default trackData to participant + no Mixer state.
                    var trackData = {
                        trackId: track.id,
                        connection_id: track.connection_id,
                        client_track_id: track.client_track_id,
                        client_resource_id: track.client_resource_id,
                        clientId: participant.client_id,
                        name: name,
                        instrumentIcon: instrumentIcon,
                        avatar: photoUrl,
                        latency: "good",
                        gainPercent: 0,
                        muteClass: 'muted',
                        mixerId: "",
                        avatarClass: 'avatar-med',
                        preMasteredClass: "",
                        myTrack: myTrack
                    };

                    var mixerData = findMixerForTrack(participant.client_id, track, myTrack)
                    var mixer = mixerData.mixer;
                    var vuMixer = mixerData.vuMixer;
                    var muteMixer = mixerData.muteMixer;
                    var oppositeMixer = mixerData.oppositeMixer;



                    if (mixer && oppositeMixer) {
                        myTrack = (mixer.group_id === ChannelGroupIds.AudioInputMusicGroup);
                        var gainPercent = percentFromMixerValue(
                            mixer.range_low, mixer.range_high, mixer.volume_left);
                        var muteClass = "enabled";
                        if (mixer.mute) {
                            muteClass = "muted";
                        }

                        trackData.gainPercent = gainPercent;
                        trackData.muteClass = muteClass;
                        trackData.mixerId = mixer.id;
                        trackData.vuMixerId = vuMixer.id;
                        trackData.oppositeMixer = oppositeMixer;
                        trackData.muteMixerId = muteMixer.id;
                        trackData.noaudio = false;
                        trackData.group_id = mixer.group_id;
                        context.jamClient.SessionSetUserName(participant.client_id,name);

                    } else { // No mixer to match, yet
                        lookingForMixers.push({track: track, clientId: participant.client_id})
                        trackData.noaudio = true;
                        if (!(lookingForMixersTimer)) {
                            logger.debug("waiting for mixer to show up for track: " + track.id)
                            lookingForMixersTimer = context.setInterval(lookForMixers, 500);
                        }
                    }

                    var allowDelete = myTrack && index > 0;
                    _addTrack(allowDelete, trackData, mixer, oppositeMixer);

                    // Show settings icons only for my tracks
                    if (myTrack) {
                        myTracks.push(trackData);
                    }
                });
            });

            configureTrackDialog = new context.JK.ConfigureTrackDialog(app, myTracks, sessionId, sessionModel);
            addNewGearDialog = new context.JK.AddNewGearDialog(app, self);
        }

        function connectTrackToMixer(trackSelector, track, mixerId, gainPercent, groupId) {
            var vuOpts = $.extend({}, trackVuOpts);
            var faderOpts = $.extend({}, trackFaderOpts);
            faderOpts.faderId = mixerId;
            var vuLeftSelector = trackSelector + " .track-vu-left";
            var vuRightSelector = trackSelector + " .track-vu-right";
            var faderSelector = trackSelector + " .track-gain";
            var $fader = $(faderSelector).attr('mixer-id', mixerId).data('groupId', groupId)
            if(track.mediaControlsDisabled) {
              $fader.data('media-controls-disabled', true).data('media-track-opener', track.mediaTrackOpener) // this we be applied later to the fader handle $element
            }
            var $track = $(trackSelector);
            // Set mixer-id attributes and render VU/Fader
            context.JK.VuHelpers.renderVU(vuLeftSelector, vuOpts);
            $track.find('.track-vu-left').attr('mixer-id', track.vuMixerId + '_vul').data('groupId', groupId)
            context.JK.VuHelpers.renderVU(vuRightSelector, vuOpts);
            $track.find('.track-vu-right').attr('mixer-id', track.vuMixerId + '_vur').data('groupId', groupId)
            context.JK.FaderHelpers.renderFader($fader, faderOpts);
            // Set gain position
            context.JK.FaderHelpers.setFaderValue(mixerId, gainPercent);
            $fader.on('fader_change', faderChanged);

          return $track;
        }

        // Function called on an interval when participants change. Mixers seem to
        // show up later, so we render the tracks from participants, but keep track
        // of the ones there weren't any mixers for, and continually try to find them
        // and get them connected to the mixers underneath.
        function lookForMixers() {
            lookingForMixersCount++;
            _updateMixers();
            var usedMixers = {};
            var keysToDelete = [];
            context._.each(lookingForMixers, function(data) {
              var clientId = data.clientId;
              var track = data.track;

              var myTrack = app.clientId == clientId;

              var mixerData = findMixerForTrack(clientId, track, myTrack)

              var mixer = mixerData.mixer;
              var oppositeMixer = mixerData.oppositeMixer;
              var vuMixer = mixerData.vuMixer;
              var muteMixer = mixerData.muteMixer;

              if (mixer && oppositeMixer) {
                var participant = (sessionModel.getParticipant(clientId) || {name:'unknown'}).name;
                logger.debug("found mixer=" + mixer.id + ", participant=" + participant)
                usedMixers[mixer.id] = true;
                keysToDelete.push(data);
                var gainPercent = percentFromMixerValue(
                  mixer.range_low, mixer.range_high, mixer.volume_left);
                var trackSelector = 'div.track[track-id="' + track.id + '"]';

                connectTrackToMixer(trackSelector, track, mixer.id, gainPercent, mixer.group_id);
                var $track = $('div.track[client-id="' + clientId + '"]');
                var $trackIconMute = $track.find('.track-icon-mute')
                $trackIconMute.attr('mixer-id', muteMixer.id).data('mixer', mixer).data('opposite-mixer', oppositeMixer)
                $trackIconMute.muteSelector().on(EVENTS.MUTE_SELECTED, trackMuteSelected)

                // hide overlay for all tracks associated with this client id (if one mixer is present, then all tracks are valid)
                $('.disabled-track-overlay', $track).hide();
                $('.track-connection', $track).removeClass('red yellow green').addClass('grey');
                // Set mute state
                _toggleVisualMuteControl($trackIconMute, mixer.mute || oppositeMixer.mute);
              }
              else {
                // if 1 second has gone by and still no mixer, then we gray the participant's tracks
                if(lookingForMixersCount == 2) {
                  var $track = $('div.track[client-id="' + clientId + '"]');
                  $('.disabled-track-overlay', $track).show();
                  $('.track-connection', $track).removeClass('red yellow green').addClass('red');
                }
                var participant = (sessionModel.getParticipant(clientId) || { user: {name: 'unknown'}}).user.name;
                logger.debug("still looking for mixer for participant=" + participant + ", clientId=" + clientId)
              }
            })

            for (var i=0; i<keysToDelete.length; i++) {
              var index = lookingForMixers.indexOf(keysToDelete[i]);
              lookingForMixers.splice(index, 1);
            }

            if (lookingForMixers.length === 0 ||
               lookingForMixersCount > 20) {
                lookingForMixersCount = 0;
                lookingForMixers = []
                context.clearTimeout(lookingForMixersTimer);
                lookingForMixersTimer = null;
            }
        }

        // Given a mixerID and a value between 0.0-1.0,
        // light up the proper VU lights.
        function _updateVU(mixerId, value, isClipping) {

            // Special-case for mono tracks. If mono, and it's a _vul id,
            // update both sides, otherwise do nothing.
            // If it's a stereo track, just do the normal thing.
            var selector;
            var pureMixerId = mixerId.replace("_vul", "");
            pureMixerId = pureMixerId.replace("_vur", "");
            var mixer = getMixer(pureMixerId);
            if (mixer) {
                if (!(mixer.stereo)) { // mono track
                    if (mixerId.substr(-4) === "_vul") {
                        // Do the left
                        selector = $('#tracks [mixer-id="' + pureMixerId + '_vul"]');
                        context.JK.VuHelpers.updateVU(selector, value);
                        // Do the right
                        selector = $('#tracks [mixer-id="' + pureMixerId + '_vur"]');
                        context.JK.VuHelpers.updateVU(selector, value);
                    } // otherwise, it's a mono track, _vur event - ignore.
                } else { // stereo track
                    selector = $('#tracks [mixer-id="' + mixerId + '"]');
                    context.JK.VuHelpers.updateVU(selector, value);
                }
            }
        }

        function _addTrack(allowDelete, trackData, mixer, oppositeMixer) {

            var parentSelector = '#session-mytracks-container';
            var $destination = $(parentSelector);
            if (trackData.clientId !== app.clientId) {
                parentSelector = '#session-livetracks-container';
                $destination = $(parentSelector);
                $('.session-livetracks .when-empty').hide();
            }
            var template = $('#template-session-track').html();
            var newTrack = $(context.JK.fillTemplate(template, trackData));
            var audioOverlay = $('.disabled-track-overlay', newTrack);
            var $trackIconMute = newTrack.find('.track-icon-mute')
            $trackIconMute.muteSelector().on(EVENTS.MUTE_SELECTED, trackMuteSelected)
            $trackIconMute.data('mixer', mixer).data('opposite-mixer', oppositeMixer)

            audioOverlay.hide(); // always start with overlay hidden, and only show if no audio persists
            $destination.append(newTrack);

            // Render VU meters and gain fader
            var trackSelector = parentSelector + ' .session-track[track-id="' + trackData.trackId + '"]';
            var gainPercent = trackData.gainPercent || 0;
            connectTrackToMixer(trackSelector, trackData, trackData.mixerId, gainPercent, trackData.group_id);

            var $closeButton = $('#div-track-close', 'div[track-id="' + trackData.trackId + '"]');
            if (!allowDelete) {
                $closeButton.hide();
            }
            else {
                $closeButton.click(deleteTrack);
            }

            // is this used?
            tracks[trackData.trackId] = new context.JK.SessionTrack(trackData.clientId);
        }



        function _addRecordingTrack(trackData) {
            var parentSelector = '#session-recordedtracks-container';
            var $destination = $(parentSelector);
            $('.session-recordings .when-empty').hide();
            $('.session-recording-name-wrapper').show();
            $('.session-recordings .recording-controls').show();

            var template = $('#template-session-track').html();
            var newTrack = $(context.JK.fillTemplate(template, trackData));
            $destination.append(newTrack);
            if(trackData.preMasteredClass) {
                context.JK.helpBubble($('.track-instrument', newTrack), 'pre-processed-track', {}, {offsetParent: newTrack.closest('.content-body')});
            }

            // Render VU meters and gain fader
            var trackSelector = parentSelector + ' .session-track[track-id="' + trackData.trackId + '"]';
            var gainPercent = trackData.gainPercent || 0;
            var $track = connectTrackToMixer(trackSelector, trackData, trackData.mixerId, gainPercent, null);
            var $trackIconMute = $track.find('.track-icon-mute')
            if(trackData.mediaControlsDisabled) {
              $trackIconMute.data('media-controls-disabled', true).data('media-track-opener', trackData.mediaTrackOpener)
            }
            // is this used?
            tracks[trackData.trackId] = new context.JK.SessionTrack(trackData.clientId);
        }

        /**
        * Will be called when fader changes. The fader id (provided at subscribe time),
        * the new value (0-100) and whether the fader is still being dragged are passed.
        */
        function faderChanged(e, data) {
            var $target =  $(this);
            var faderId = $target.attr('mixer-id');
            var groupId = $target.data('groupId');
            var mixerIds = faderId.split(',');
            $.each(mixerIds, function(i,v) {
                var broadcast = !(data.dragging);  // If fader is still dragging, don't broadcast
                fillTrackVolumeObject(v, broadcast);
                setMixerVolume(v, data.percentage);

                if(groupId == ChannelGroupIds.UserMusicInputGroup) {
                  // there may be other mixers with this same ID in the case of a Peer Music Stream, so update them as well
                  context.JK.FaderHelpers.setFaderValue(v, data.percentage);
                }
            });
        }

        function handleVolumeChangeCallback(mixerId, isLeft, value, isMuted) {
            // Visually update mixer
            // There is no need to actually set the back-end mixer value as the
            // back-end will already have updated the audio mixer directly prior to sending
            // me this event. I simply need to visually show the new fader position.
            // TODO: Use mixer's range
            var faderValue = percentFromMixerValue(-80, 20, value);
            context.JK.FaderHelpers.setFaderValue(mixerId, faderValue);
            var $muteControl = $('[control="mute"][mixer-id="' + mixerId + '"]');
            _toggleVisualMuteControl($muteControl, isMuted);
        }

          function handleBridgeCallback(vuData) {
            var j;
            var eventName = null;
            var mixerId = null;
            var value = null;
            var vuInfo = null;
            for (j = 0; j < vuData.length; j++) {
              vuInfo = vuData[j];
              var eventName = vuInfo[0];
              var vuVal = 0.0;
              if(eventName === "vu") {
                var mixerId         = vuInfo[1];
                var leftValue       = vuInfo[2];
                var leftClipping    = vuInfo[3];
                var rightValue      = vuInfo[4];
                var rightClipping   = vuInfo[5];
                // TODO - no guarantee range will be -80 to 20. Get from the
                // GetControlState for this mixer which returns min/max
                // value is a DB value from -80 to 20. Convert to float from 0.0-1.0
                _updateVU(mixerId + "_vul", (leftValue + 80) / 100, leftClipping);
                _updateVU(mixerId + "_vur", (rightValue + 80) / 100, rightClipping);
              }
              else if(eventName === 'connection_status') {
                var mixerId = vuInfo[1];
                var value   = vuInfo[2];

                // Connection Quality Change
                var connectionClass = 'green';
                if (value < 7) {
                  connectionClass = 'yellow';
                }
                if (value < 4) {
                  connectionClass = 'red';
                }
                var mixerPair = getMixerByTrackId(mixerId);

                var clientId = mixerPair ? mixerPair.master.client_id : null;

                if(clientId) {
                  var $connection = $('.session-track[client-id="' + clientId + '"] .track-connection');
                  if($connection.length == 0) {
                    logger.debug("connection status: looking for clientId: " + clientId + ", mixer: " + mixerId)
                  }
                  else {
                    $connection.removeClass('red yellow green grey');
                    $connection.addClass(connectionClass);
                  }
                }
              }
              else if(eventName === 'add' || eventName === 'remove') {
                // TODO - _renderSession. Note I get streams of these in
                // sequence, so have Nat fix, or buffer/spam protect
                // Note - this is already handled from websocket events.
                // However, there may be use of these two events to avoid
                // the polling-style check for when a mixer has been added
                // to match a participant track.
              }
              else {
                logger.debug('non-vu event: ' + JSON.stringify(vuInfo));
              }
            }
          }


        function deleteSession(evt) {
            var sessionId = $(evt.currentTarget).attr("action-id");
            if (sessionId) {
                $.ajax({
                    type: "DELETE",
                    url: "/api/sessions/" + sessionId,
                    success: function(response) {
                        context.location="/client#/home";
                    },
                    error: function(jqXHR, textStatus, errorThrown) {
                        logger.error("Error deleting session " + sessionId);
                    }
                });
            }
        }

        function deleteTrack(evt) {
            var trackId = $(evt.currentTarget).attr("track-id");
            sessionModel.deleteTrack(sessionId, trackId);
        }

        function _toggleVisualMuteControl($control, mute) {
            if (mute) {
                $control.removeClass('enabled');
                $control.addClass('muted');
            } else {
                $control.removeClass('muted');
                $control.addClass('enabled');
            }
        }

        function _toggleAudioMute(mixerId, muting, mode) {
            fillTrackVolumeObject(mixerId);
            context.trackVolumeObject.mute = muting;

            if(mode === undefined) {
              mode = sessionModel.getMixMode();
            }
            context.jamClient.SessionSetControlState(mixerId, mode);
        }

        function showMuteDropdowns($control) {
          $control.btOn();
        }

        function toggleMute(evt) {
            var $control = $(evt.currentTarget);
            var muting = ($control.hasClass('enabled'));
            var mixerIds = $control.attr('mixer-id').split(',');

            // track icons have a special mute behavior
            if($control.is('.track-icon-mute')) {

              var mediaControlsDisabled = $control.data('media-controls-disabled');
              if(mediaControlsDisabled) {
                var mediaTrackOpener = $control.data('media-track-opener');
                context.JK.prodBubble($control, 'media-controls-disabled', {mediaTrackOpener:mediaTrackOpener}, {positions:['bottom'], offsetParent: $control.closest('.screen')})
                return false;
              }

              $.each(mixerIds, function(i,v) {
                  var mixerId = v;
                  // behavior: if this is the user's track in personal mode, then we mute the track globally
                  // otherwise, for any other track (user+master mode, or remote track in any mode)
                  // we just mute the type of track for that mode
                  var mixer = $control.data('mixer');
                  var oppositeMixer = $control.data('opposite-mixer')

                  if(mixer && oppositeMixer && mixer.group_id == ChannelGroupIds.AudioInputMusicGroup) {
                    // this is the user's local track; mute both personal and master mode
                    _toggleAudioMute(mixer.id, muting, getMixer(mixer.id).mode)
                    _toggleAudioMute(oppositeMixer.id, muting, getMixer(oppositeMixer.id).mode)
                  }
                  else {
                    _toggleAudioMute(mixer.id, muting, getMixer(mixer.id).mode)
                  }

                  // look for all controls matching this mixer id (important when it's personal mode + UserMusicInputGroup)
                  var $controls = $screen.find('.track-icon-mute[mixer-id=' + mixerId +']');
                  _toggleVisualMuteControl($controls, muting);
              });
            }
            else {
              // this path is taken for voice chat, but maybe others eventually
              $.each(mixerIds, function(i,v) {
                var mixerId = v;

                var mixer = $control.data('mixer');
                var oppositeMixer = $control.data('opposite-mixer')

                if(mixer && oppositeMixer && mixer.group_id == ChannelGroupIds.AudioInputChatGroup) {
                  _toggleAudioMute(mixer.id, muting, mixer.mode);
                  _toggleAudioMute(oppositeMixer.id, muting, oppositeMixer.mode);
                }
                else {
                  _toggleAudioMute(mixerId, muting);
                }
              });
              _toggleVisualMuteControl($control, muting);
            }


        }

        function fillTrackVolumeObject(mixerId, broadcast) {
            _updateMixers();
            var _broadcast = true;
            if (broadcast !== undefined) {
                _broadcast = broadcast;
            }
            var mixer =  getMixer(mixerId);
            context.trackVolumeObject.clientID = mixer.client_id;
            context.trackVolumeObject.broadcast = _broadcast;
            context.trackVolumeObject.master = mixer.master;
            context.trackVolumeObject.monitor = mixer.monitor;
            context.trackVolumeObject.mute = mixer.mute;
            context.trackVolumeObject.name = mixer.name;
            context.trackVolumeObject.record = mixer.record;
            context.trackVolumeObject.volL = mixer.volume_left;
            context.trackVolumeObject.volR = mixer.volume_right;
            // trackVolumeObject doesn't have a place for range min/max
            currentMixerRangeMin = mixer.range_low;
            currentMixerRangeMax = mixer.range_high;
        }

        // Given a mixer's min/max and current value, return it as
        // a percent from 0-100. Return an integer.
        function percentFromMixerValue(min, max, value) {
            try {
                var range = Math.abs(max - min);
                var magnitude = value - min;
                var percent = Math.round(100*(magnitude/range));
                return percent;
            } catch(err) {
                return 0;
            }
        }

        // Given a mixer's min/max and a percent value, return it as
        // the mixer's value. Returns an integer.
        function percentToMixerValue(min, max, percent) {
            var range = Math.abs(max - min);
            var multiplier = percent/100; // Change 85 into 0.85
            var value = min + (multiplier * range);
            // Protect against percents < 0 and > 100
            if (value < min) {
                value = min;
            }
            if (value > max) {
                value = max;
            }
            return value;
        }

        // Given a volume percent (0-100), set the underlying
        // audio volume level of the passed mixerId to the correct
        // value.
        function setMixerVolume(mixerId, volumePercent) {
            // The context.trackVolumeObject has been filled with the mixer values
            // that go with mixerId, and the range of that mixer
            // has been set in currentMixerRangeMin-Max.
            // All that needs doing is to translate the incoming percent
            // into the real value ont the sliders range. Set Left/Right
            // volumes on trackVolumeObject, and call SetControlState to stick.
            var sliderValue = percentToMixerValue(
                currentMixerRangeMin, currentMixerRangeMax, volumePercent);
            context.trackVolumeObject.volL = context.JK.FaderHelpers.convertPercentToAudioTaper(volumePercent);
            context.trackVolumeObject.volR = context.JK.FaderHelpers.convertPercentToAudioTaper(volumePercent);
            // Special case for L2M mix:
            if (mixerId === '__L2M__') {
                logger.debug("L2M volumePercent=" + volumePercent);
                var dbValue = context.JK.FaderHelpers.convertLinearToDb(volumePercent);
                context.jamClient.SessionSetMasterLocalMix(dbValue);
                // context.jamClient.SessionSetMasterLocalMix(sliderValue);
            } else {
                context.jamClient.SessionSetControlState(mixerId, sessionModel.getMixMode());
            }
        }

        function bailOut() {
            promptLeave = false; 
            context.window.location = '/client#/home';
        }

        function sessionLeave(evt) {
          evt.preventDefault();
          rateSession();
            bailOut();
          return false;
        }

        function rateSession() {
            if (rateSessionDialog === null) {
                rateSessionDialog = new context.JK.RateSessionDialog(context.JK.app);
                rateSessionDialog.initialize();
            }
            rateSessionDialog.showDialog();
            return true;
        }

        function sessionResync(evt) {
            evt.preventDefault();
            var response = context.jamClient.SessionAudioResync();
            if (response) {
                app.notify({
                  "title": "Error",
                  "text": response,
                  "icon_url": "/assets/content/icon_alert_big.png"});
            }
            return false;
        }

        // http://stackoverflow.com/questions/2604450/how-to-create-a-jquery-clock-timer
        function updateRecordingTimer() {

            function pretty_time_string(num) {
                return ( num < 10 ? "0" : "" ) + num;
            }

            var total_seconds = (new Date - startTimeDate) / 1000;

            var hours = Math.floor(total_seconds / 3600);
            total_seconds = total_seconds % 3600;

            var minutes = Math.floor(total_seconds / 60);
            total_seconds = total_seconds % 60;

            var seconds = Math.floor(total_seconds);

            hours = pretty_time_string(hours);
            minutes = pretty_time_string(minutes);
            seconds = pretty_time_string(seconds);

            if(hours > 0) {
                var currentTimeString = hours + ":" + minutes + ":" + seconds;
            }
            else {
                var currentTimeString = minutes + ":" + seconds;
            }

            $recordingTimer.text('(' + currentTimeString + ')');
        }

        function displayStartingRecording() {

            $('#recording-start-stop').addClass('currently-recording');

            $('#recording-status').text("Starting...")
        }

        function displayStartedRecording() {
            startTimeDate = new Date;
            $recordingTimer = $("<span id='recording-timer'>(0:00)</span>");
            var $recordingStatus = $('<span></span>').append("<span>Stop Recording</span>").append($recordingTimer);
            $('#recording-status').html( $recordingStatus );
            recordingTimerInterval =  setInterval(updateRecordingTimer, 1000);
        }

        function displayStoppingRecording(data) {
            if(data) {
                if(data.reason) {
                    app.notify({
                        "title": "Recording Aborted",
                        "text": "The recording was aborted due to '" + data.reason + '"',
                        "icon_url": "/assets/content/icon_alert_big.png"
                    });
                }
            }

            $('#recording-status').text("Stopping...");
        }

        function displayDoneRecording() {
            if(recordingTimerInterval) {
                clearInterval(recordingTimerInterval);
                recordingTimerInterval = null;
                startTimeDate = null;
            }

            $recordingTimer = null;

            $('#recording-start-stop').removeClass('currently-recording');
            $('#recording-status').text("Make a Recording");
        }

        function displayWhoCreated(clientId) {
            if(app.clientId != clientId) { // don't show to creator
                sessionModel.findUserBy({clientId: clientId})
                    .done(function(user) {
                        app.notify({
                            "title": "Recording Started",
                            "text": user.name + " started a recording",
                            "icon_url": context.JK.resolveAvatarUrl(user.photo_url)
                        });
                    })
                    .fail(function() {
                        app.notify({
                            "title": "Recording Started",
                            "text": "Oops! Can't determine who started this recording",
                            "icon_url": "/assets/content/icon_alert_big.png"
                            });
                    })
            }
        }

        function promptUserToSave(recordingId) {
            rest.getRecording( {id: recordingId} )
                .done(function(recording) {
                    recordingFinishedDialog.setRecording(recording);
                    app.layout.showDialog('recordingFinished').one(EVENTS.DIALOG_CLOSED, function(e, data) {
                      if(data.result && data.result.keep){
                        context.JK.prodBubble($recordingManagerViewer, 'file-manager-poke', {}, {positions:['top', 'left', 'right', 'bottom'], offsetParent: $screen.parent()})
                      }
                    })
                })
                .fail(app.ajaxError);
        }

        function openRecording(e) {
            // just ignore the click if they are currently recording for now
            if(sessionModel.recordingModel.isRecording()) {
                app.notify({
                    "title": "Currently Recording",
                    "text": "You can't open a recording while creating a recording.",
                    "icon_url": "/assets/content/icon_alert_big.png"
                });
                return false;
            }

            if(!localRecordingsDialog.isShowing()) {
                app.layout.showDialog('localRecordings');
            }

            return false;
        }

        function closeRecording() {
            rest.stopPlayClaimedRecording({id: sessionModel.id(), claimed_recording_id: sessionModel.getCurrentSession().claimed_recording.id})
                .done(function() {
                    sessionModel.refreshCurrentSession();
                })
                .fail(function(jqXHR) {
                    app.notify({
                        "title": "Couldn't Stop Recording Playback",
                        "text": "Couldn't inform the server to stop playback. msg=" + jqXHR.responseText,
                        "icon_url": "/assets/content/icon_alert_big.png"
                    });
                });

            context.jamClient.CloseRecording();

            return false;
        }

        function onPause() {
            logger.debug("calling jamClient.SessionStopPlay");
            context.jamClient.SessionStopPlay();
        }

        function onPlay(e, data) {
            logger.debug("calling jamClient.SessionStartPlay");
            context.jamClient.SessionStartPlay(data.playbackMode);
        }

        function onChangePlayPosition(e, data){
            logger.debug("calling jamClient.SessionTrackSeekMs(" + data.positionMs + ")");
            context.jamClient.SessionTrackSeekMs(data.positionMs);
        }

        function startStopRecording() {
            if(sessionModel.recordingModel.isRecording()) {
                sessionModel.recordingModel.stopRecording();
            }
            else {
                sessionModel.recordingModel.startRecording();
            }
        }

        function inviteMusicians() {
            friendInput = inviteMusiciansUtil.inviteSessionUpdate('#update-session-invite-musicians', 
                                                                  sessionId);
            inviteMusiciansUtil.loadFriends();
            $(friendInput).show();
          }

        function onMixerModeChanged(e, data)
        {
          $mixModeDropdown.easyDropDown('select', data.mode, true);

          setTimeout(renderSession, 1);
        }

        function onUserChangeMixMode(e) {
          var mode = $mixModeDropdown.val() == "master" ? MIX_MODES.MASTER : MIX_MODES.PERSONAL;

          context.jamClient.SetMixerMode(mode)

          modUtils.shouldShow(NAMED_MESSAGES.MASTER_VS_PERSONAL_MIX).done(function(shouldShow) {
            if(shouldShow) {
              var modeChangeHtml = $($templateMixerModeChange.html());
              context.JK.Banner.show({title: 'Master vs. Personal Mix', text: modeChangeHtml, no_show: NAMED_MESSAGES.MASTER_VS_PERSONAL_MIX});
            }
          })

          return true;
        }

        function events() {
            $('#session-leave').on('click', sessionLeave);
            $('#session-resync').on('click', sessionResync);
            $('#session-contents').on("click", '[action="delete"]', deleteSession);
            $('#tracks').on('click', 'div[control="mute"]', toggleMute);
            $('#recording-start-stop').on('click', startStopRecording);
            $('#open-a-recording').on('click', openRecording);
            $('#session-invite-musicians').on('click', inviteMusicians);
            $('#session-invite-musicians2').on('click', inviteMusicians);
            $('#track-settings').click(function() {
                configureTrackDialog.refresh();
                configureTrackDialog.showVoiceChatPanel(true);
                configureTrackDialog.showMusicAudioPanel(true);
            });

            $('#close-playback-recording').on('click', closeRecording);
            $(playbackControls)
                .on('pause', onPause)
                .on('play', onPlay)
                .on('change-position', onChangePlayPosition);
            $(friendInput).focus(function() { $(this).val(''); })
            $(document).on(EVENTS.MIXER_MODE_CHANGED, onMixerModeChanged)
            $mixModeDropdown.change(onUserChangeMixMode)
        }

        this.initialize = function(localRecordingsDialogInstance, recordingFinishedDialogInstance, friendSelectorDialog) {
            inviteMusiciansUtil = new JK.InviteMusiciansUtil(JK.app);
            inviteMusiciansUtil.initialize(friendSelectorDialog);
            localRecordingsDialog = localRecordingsDialogInstance;
            recordingFinishedDialog = recordingFinishedDialogInstance;
            context.jamClient.SetVURefreshRate(150);
            context.jamClient.RegisterVolChangeCallBack("JK.HandleVolumeChangeCallback");
            playbackControls = new context.JK.PlaybackControls($('.session-recordings .recording-controls'));

            var screenBindings = {
                'beforeShow': beforeShow,
                'afterShow': afterShow,
                'beforeHide': beforeHide,
                'beforeLeave' : beforeLeave,
                'beforeDisconnect' : beforeDisconnect,
            };
            app.bindScreen('session', screenBindings);

            $recordingManagerViewer = $('#recording-manager-viewer');
            $screen = $('#session-screen');
            $mixModeDropdown = $screen.find('select.monitor-mode')
            $templateMixerModeChange = $('#template-mixer-mode-change');
            events();


          // make sure no previous plays are still going on by accident
            context.jamClient.SessionStopPlay();
            if(context.jamClient.SessionRemoveAllPlayTracks) {
              // upgrade guard
              context.jamClient.SessionRemoveAllPlayTracks();
            }
        };


        this.tracks = tracks;

        this.getCurrentSession = function() {
            return sessionModel.getCurrentSession();
        };

        this.refreshCurrentSession = function(force) {
            sessionModel.refreshCurrentSession(force);
        };

        this.setPromptLeave = function(_promptLeave) {
          promptLeave = _promptLeave;
        }

        context.JK.HandleVolumeChangeCallback = handleVolumeChangeCallback;
        context.JK.HandleBridgeCallback = handleBridgeCallback;
    };

 })(window,jQuery);