var panopticon;

class Panopticon {
    constructor() {
        console.log( "Init panopticon" );
        this.languages = []
//        this.selectedHugvey = null;
        this.hugveys = new Vue( {
            el: "#interface",
            data: {
                uptime: 0,
                languages: [],
                hugveys: [],
                selectedId: null,
            },
            methods: {
                time_passed: function( hugvey, property ) {
                    console.log( "property!", Date( hugvey[property] * 1000 ) );
                    return moment( Date( hugvey[property] * 1000 ) ).fromNow();
                },
                timer: function(hugvey, property) {
                    return panopticon.stringToHHMMSS( hugvey[property] );
                },
                loadNarrative: function( code, file ) {
                    panopticon.hugveys.selectedId = null;
                    return panopticon.loadNarrative( code, file );
                },
                pause: function(hv) {
                    hv.status = "loading";
                    return panopticon.pause(hv.id);
                },
                resume: function(hv) {
                    hv.status = "loading";
                    return panopticon.resume(hv.id);
                },
                restart: function(hv) {
                    hv.status = "loading";
                    return panopticon.restart(hv.id);
                },
                change_lang: function(hv, lang_code) {
                    hv.status = "loading";
                    return panopticon.change_language(hv.id, lang_code);
                },
                showHugvey: function(hv) {
                    panopticon.hugveys.selectedId = hv.language ? hv.id : null;
                    panopticon.updateSelectedHugvey();
                }
            }
        } );



        this.socket = new ReconnectingWebSocket( "ws://localhost:8888/ws", null, { debug: false, reconnectInterval: 3000 } );
        this.graph = new Graph();


        this.socket.addEventListener( 'open', ( e ) => {
            this.send( { action: 'init' } );
        } );

        this.socket.addEventListener( 'close', function( e ) {
            console.log( 'Closed connection' );
        } );
        this.socket.addEventListener( 'message', ( e ) => {
            let msg = JSON.parse( e.data );
            if ( typeof msg['alert'] !== 'undefined' ) {
                alert( msg['alert'] );
            }

            if ( typeof msg['action'] === 'undefined' ) {
                console.error( "not a valid message: " + e.data );
                return;
            }

            switch ( msg['action'] ) {

                case 'status':
                    console.debug(msg);
                    this.hugveys.uptime = this.stringToHHMMSS( msg['uptime'] );
                    this.hugveys.languages = msg['languages'];
                    this.languages = msg['languages'];
                    this.hugveys.hugveys = msg['hugveys'];
                    if(this.hugveys.selectedId) {
                        this.updateSelectedHugvey();
                    }
                    break;
            }
        } );
    }
    
    updateSelectedHugvey() {
        let hv = null;
        if(this.hugveys.selectedId) {
            hv = this.getHugvey(this.hugveys.selectedId);
            if(hv.language && this.graph.language_code != hv.language) {
                this.loadNarrative(hv.language);
            }
        }
        this.graph.updateHugveyStatus(hv);
    }
    
    getHugvey(id) {
        for(let hv of this.hugveys.hugveys) {
            if(hv.id == id) {
                return hv;
            }
        }
        return null;
    }

    send( msg ) {
        if ( this.socket.readyState == WebSocket.OPEN ) {
            this.socket.send( JSON.stringify( msg ) );
        } else {
            console.error( "Socket not open: ", this.socket.readyState );
        }
    }

    getStatus() {
        //        console.log('get status', this, panopticon);
        panopticon.send( { action: 'get_status' } );
    }

    init() {
        setInterval( this.getStatus, 3000 );
    }

    stringToHHMMSS( string ) {
        var sec_num = parseInt( string, 10 ); // don't forget the second param
        var hours = Math.floor( sec_num / 3600 );
        var minutes = Math.floor(( sec_num - ( hours * 3600 ) ) / 60 );
        var seconds = sec_num - ( hours * 3600 ) - ( minutes * 60 );

        if ( hours < 10 ) { hours = "0" + hours; }
        if ( minutes < 10 ) { minutes = "0" + minutes; }
        if ( seconds < 10 ) { seconds = "0" + seconds; }
        return hours + ':' + minutes + ':' + seconds;
    }

    loadNarrative( code, file ) {
        if(typeof file == 'undefined') {
            for (let lang of this.languages) {
                if (lang['code'] == code) {
                    file = lang['file'];
                }
            }
        }
        let req = new XMLHttpRequest();
        let graph = this.graph;
        req.addEventListener( "load", function( e ) {
            graph.loadData( JSON.parse( this.response ), code );
            //           console.log(, e); 
        } );
        req.open( "GET", "/local/" + file );
        req.send();
    }

    resume( hv_id ) {
        this.send( { action: 'resume', hugvey: hv_id } )
    }
    pause( hv_id ) {
        this.send( { action: 'pause', hugvey: hv_id } )
    }
    restart( hv_id ) {
        this.send( { action: 'restart', hugvey: hv_id } );
    }
    change_language( hv_id, lang_code ) {
        this.send( { action: 'change_language', hugvey: hv_id, lang_code: lang_code } );
    }
    
    playFromSelected(msg_id) {
        if(!this.hugveys.selectedId) {
            alert('No hugvey selected');
        } else {
            this.send({ action: 'play_msg', hugvey: this.hugveys.selectedId, msg_id: msg_id })
        }
    }
}



window.addEventListener( 'load', function() {
    panopticon = new Panopticon();
    panopticon.init();
} );

class Graph {
    constructor() {
        this.width = 1280;
        this.height = 1024;
        this.nodeSize = 80;
        this.maxChars = 16;
        this.svg = d3.select( '#graph' );
        this.container = d3.select( '#container' );
        this.selectedMsg = null;
        this.language_code = null;
        this.messages = []; // initialise empty array. For the simulation, make sure we keep the same array object
        this.directions = []; // initialise empty array. For the simulation, make sure we keep the same array object
        this.conditions = []; // initialise empty array. For the simulation, make sure we keep the same array object
        this.diversions = []; // initialise empty array. For the simulation, make sure we keep the same array object

        let graph = this;
        this.controlDown = false;
        document.addEventListener( 'keydown', function( e ) {
            console.log( e );
            if ( e.which == "17" ) {
                graph.controlDown = true;
                document.body.classList.add( 'controlDown' );
            }
        } );
        document.addEventListener( 'keyup', function( e ) {
            console.log( e );
            if ( e.which == "17" ) {
                graph.controlDown = false;
                document.body.classList.remove( 'controlDown' );
            }
        } );

        let c = this.container;
        let zoomed = function() {
            c.attr( "transform", d3.event.transform );
        }
        this.svg.call( d3.zoom()
            .scaleExtent( [1 / 2, 8] )
            .on( "zoom", zoomed ) );

        this.nodesG = this.container.append( "g" )
            .attr( "id", "nodes" )

        this.linkG = this.container.append( "g" )
            .attr( "id", "links" );

        document.getElementById( 'btn-save' ).addEventListener( 'click', function( e ) { graph.saveJson(); } );
        document.getElementById( 'btn-addMsg' ).addEventListener( 'click', function( e ) { graph.createMsg(); } );
    }

    clickMsg( msg ) {
        // event when a message is clicked.
        console.log( msg );

        if ( this.controlDown ) {
            this.secondarySelectMsg( msg );
        } else {
            this.selectMsg( msg );
        }
    }

    secondarySelectMsg( msg ) {
        if ( this.selectedMsg !== null ) {
            this.addDirection( this.selectedMsg, msg );
        } else {
            console.error( 'No message selected as Source' );
        }
    }

    selectMsg( msg ) {
        let selectedEls = document.getElementsByClassName( 'selectedMsg' );
        while ( selectedEls.length > 0 ) {
            selectedEls[0].classList.remove( 'selectedMsg' );
        }
        document.getElementById( msg['@id'] ).classList.add( 'selectedMsg' );

        this.selectedMsg = msg;

        this.showMsg( msg );
    }

    updateMsg() {
        // used eg. after a condition creation.
        this.showMsg( this.selectedMsg );
    }

    showMsg( msg ) {
        let msgEl = document.getElementById( 'msg' );
        msgEl.innerHTML = "";
        
        if(msg == null){
            return;
        }
        
        
        
        let startAttributes = {
            'name': msg['@id'] + '-start',
            'disabled': true,
            'type': 'checkbox',
            'on': {
                'change': this.getEditEventListener()
            }
        }
        if ( msg['start'] == true ) {
            startAttributes['checked'] = 'checked';
        }
        let audioSpan = crel(
                'span',
                {
                    'title':  msg['audio'] ?  msg['audio']['file'] : "",
                    'class': "label-value",
                },
                msg['audio'] ? msg['audio']['original_name'] : "" 
            );
        if(msg['audio']) {
            audioSpan.appendChild(crel(
                    'audio', {'controls': 'controls'},
                    crel('source', {'src':msg['audio']['file']})
                    ));
        }
        let msgInfoEl = crel( 'div', { 'class': 'msg__info' },
            crel('div', {
                'class':'btn btn--delete',
                'on': {
                    'click': function(e) {
                        if(confirm(`Are you sure you want to remove message ${msg['@id']}`)) {
                            panopticon.graph.rmMsg(msg);
                            panopticon.graph.showMsg(null);
                        }
                    }
                }
             }, 'delete'),
            crel( 'h1', { 'class': 'msg__id' }, msg['@id'] ),
            crel( 'label',
                crel( 'span', 'Text' ),
                crel( 'input', {
                    'name': msg['@id'] + '-text',
                    'value': msg['text'],
                    'on': {
                        'change': this.getEditEventListener()
                    }
                } )
            ),
            crel( 'label',
                crel( 'span', 'Start' ),
                crel( 'input', startAttributes )
            ),

            crel( 'label',
                crel( 'span', 'Audio' ),
                audioSpan,
                crel( 'input', {
                    'type': 'file',
                    'name': 'audio',
                    'accept': '.wav,.ogg,.mp3',
                    'on': {
                        'change': function(e) {
                            audioSpan.innerHTML = "...";
                            panopticon.graph.saveJson(msg['@id'], e.target, function(e2){
                                console.log(e);
                                audioSpan.innerHTML = e.target.files[0].name + "<sup>*</sup>";
                                // reload graph:
                                console.log('reload', panopticon.graph.language_code);
                                panopticon.loadNarrative(panopticon.graph.language_code);
                            });
//                            console.log(this,e);
                        }
                    }
                } )
            )
        );
        msgEl.appendChild( msgInfoEl );
        

        
        if(panopticon.hugveys.selectedId) {
            let playEl = crel(
                'div',
                {'class': 'play'},
                crel(
                    'div', {
                        'class': 'btn btn--play',
                        'on': {
                            'click': function (e) {
                                console.log('go save');
                                panopticon.graph.saveJson(null, null, function(){
                                    console.log('saved, now play');
                                    panopticon.playFromSelected(msg['@id']);
                                });
                            }
                        }
                    },
                    "Save & play on #" + panopticon.hugveys.selectedId
                )
            );
            msgEl.appendChild(playEl);
        }
        

        // let directionHEl = document.createElement('h2');
        // directionHEl.innerHTML = "Directions";

        let fromDirections = [], toDirections = [];

        for ( let direction of this.getDirectionsTo( msg ) ) {
            toDirections.push( this.getDirectionEl( direction, msg ) );
        }

        for ( let direction of this.getDirectionsFrom( msg ) ) {
            fromDirections.push( this.getDirectionEl( direction, msg ) );
        }
        let directionsEl = crel( 'div', { 'class': 'directions' },
            crel( 'h2', 'Directions' ),
            ...toDirections, ...fromDirections
        );
        msgEl.appendChild( directionsEl );

    }

    getDirectionEl( direction, msg ) {
        let g = this;
        let directionEl = crel('div',
                {
                    'class': 'direction ' + (direction['source'] == msg ? 'dir-to' : 'dir-from'),
                    'on': {
                        'mouseover': function(e) {
                            directionEl.classList.add('dir-highlight');
                            document.getElementById(direction['@id']).classList.add('dir-highlight');
                        },
                        'mouseout': function(e) {
                            directionEl.classList.remove('dir-highlight');
                            document.getElementById(direction['@id']).classList.remove('dir-highlight');
                        }
                    }
                },
                crel(
                    'h3',
                    {'title': direction['@id']},
                    direction['source'] == msg ? `To ${direction['target']['@id']}`: `From ${direction['source']['@id']}`
                    ),
                crel('div', {
                    'class':'btn btn--delete',
                    'on': {
                        'click': ( e ) => {
                            if(confirm("Do you want to remove this direction and its conditions?")) {
                                g.rmDirection( direction );   
                            }
                        }
                    }
                }, 'disconnect')
        );
        
        for ( let conditionId of direction['conditions'] ) {
            let condition = this.getNodeById( conditionId );
            directionEl.appendChild( this.getEditConditionFormEl( condition, direction ) );
        }

        directionEl.appendChild( this.getAddConditionFormEl( direction ) );

        return directionEl;
    }

    getEditConditionFormEl( condition, direction ) {
        let conditionEl = crel( 'div', { 'class': 'condition condition--edit' },
            crel( 'h4', { 'title': condition['@id'] }, condition['type'] ),
            crel('div', {
                'class':'btn btn--delete',
                'on': {
                    'click': ( e ) => {
                        if(confirm("Do you want to remove this condition?")) {
                            panopticon.graph.rmCondition( condition, direction );   
                        }
                    }
                }
            }, 'delete')
        )
        let labelLabel = document.createElement( 'label' );
        labelLabel.innerHTML = "Description";
        let labelInput = crel( 'input', {
            'name': `${condition['@id']}-label`,
            'value': typeof condition['label'] == 'undefined' ? "" : condition['label'],
            'on': {
                'change': this.getEditEventListener()
            }
        } );
        labelLabel.appendChild( labelInput );
        conditionEl.appendChild( labelLabel );

        for ( let v in condition['vars'] ) {
            let varLabel = document.createElement( 'label' );
            varLabel.innerHTML = v;
            let varInput = document.createElement( 'input' );
            if ( v == 'seconds' ) {
                varInput.type = 'number';
            }
            varInput.name = `${condition['@id']}-vars.${v}`;
            varInput.value = condition['vars'][v];
            varInput.addEventListener( 'change', this.getEditEventListener() );
            varLabel.appendChild( varInput );
            conditionEl.appendChild( varLabel );
        }
        return conditionEl;
    }

    getConditionTypes() {
        if ( typeof this.conditionTypes === 'undefined' ) {
            // type: vars: attribtes for crel()
            this.conditionTypes = {
                'timeout': {
                    'seconds': { 'type': 'number', 'value': 10, 'min': 0, 'step': 0.1 }
                },
                'replyContains': {
                    'regex': { 'value': '.+' }
                }
            }
        }
        return this.conditionTypes;
    }

    fillConditionFormForType( conditionForm, type ) {
        conditionForm.innerHTML = "";
        let vars = this.getConditionTypes()[type];
        for ( let v in vars ) {
            let attr = vars[v];
            attr['name'] = v;
            conditionForm.appendChild(
                crel( 'label',
                    crel( 'span', v ),
                    crel( 'input', attr )
                )
            );
        }
    }

    getAddConditionFormEl( direction ) {

        let optionEls = [];
        let types = this.getConditionTypes();
        for ( let type in types ) {
            optionEls.push( crel( 'option', type ) );
        }

        let conditionForm = crel( 'div', { 'class': 'condition--vars' } );
        let g = this;
        let addConditionEl = crel( 'div', { 'class': 'condition condition--add' },
            crel( 'form', {
                'on': {
                    'submit': function( e ) {
                        e.preventDefault();
                        let form = new FormData( e.target );
                        console.log( 'submit', form );
                        let type = form.get( 'type' );
                        form.delete( 'type' );
                        let label = form.get( 'label' );
                        form.delete( 'label' );
                        let vars = {};
                        for ( var pair of form.entries() ) {
                            vars[pair[0]] = pair[1];
                        }
                        g.addConditionForDirection( type, label, vars, direction );
                    }
                }
            },
                crel( "h4", {
                    'class': "divToggle",
                    'on': {
                        'click': function(e) { this.classList.toggle('opened'); }
                    }
                }, "Create New Condition" ),
                crel('div', {'class': 'divToggle-target'},
                    crel( "label",
                        crel( 'span', "Type" ),
                        crel( 'select', {
                            'name': 'type',
                            'on': {
                                'change': function( e ) {
                                    g.fillConditionFormForType( conditionForm, e.target.value );
                                }
                            }
                        }, optionEls ),
                    ),
                    crel( "label",
                        crel( 'span', "Description" ),
                        crel( 'input', { 'name': 'label' } )
                    ),
                    conditionForm,
                    crel( 'input', {
                        'type': 'submit',
                        'value': 'create'
                    } )
                )
            )
        );
        this.fillConditionFormForType( conditionForm, optionEls[0].value );

        return addConditionEl;
    }
    
    /**
     * remove condition from the graph or merely from the given direction
     * @param {any} condition The condition to remove
     * @param {any} direction if given, only remove from this direction
     */
    rmCondition( condition, direction ) {
        let id = condition['@id'];
        // TODO
        if ( typeof direction != 'undefined' ) {
            let pos = direction['conditions'].indexOf(id);
            if(pos > -1) {
                direction['conditions'].splice(pos, 1);
            }
            
            for(let dir of this.directions) {
                if(dir['conditions'].indexOf(id) > 0) {
                    console.log("Condition still in use");
                    this.updateFromData();
                    this.build();
                    this.updateMsg();
                    return;
                }
            }
            this._rmNode( id );
        } else {
            for(let dir of this.directions) {
                let pos = dir['conditions'].indexOf(id);
                if(pos > -1) {
                    dir['conditions'].splice(pos, 1);
                }
            }
            this._rmNode( id );
        }
        this.updateMsg();
    }

    getConditionEl( condition ) {
        let conditionEl = document.createElement( 'div' );

        return conditionEl;
    }

    getDirectionsFrom( msg ) {
        return this.directions.filter( d => d['source'] == msg );
    }

    getDirectionsTo( msg ) {
        return this.directions.filter( d => d['target'] == msg );
    }


    addMsg() {
        let msg = {
            "@id": this.language_code.substring( 0, 2 ) + "-n" + Date.now().toString( 36 ),
            "@type": "Msg",
            "text": "New",
            "start": false
        }
        this.data.push( msg );
        this.updateFromData();
        this.build();
        
        this.selectMsg(msg);
        return msg;
    }

    rmMsg( msg ) {
        let invalidatedDirections = this.directions.filter( d => d['source'] == msg || d['target'] == msg );
        console.log( 'invalidated', invalidatedDirections );
        for ( let dir of invalidatedDirections ) {
            let i = this.data.indexOf( dir );
            this.data.splice( i, 1 );
        }
        this._rmNode( msg );
    }

    _rmNode( node ) {
        // remove msg/direction/condition/etc
        let i = this.data.indexOf( node );
        this.data.splice( i, 1 );
        this.updateFromData();
        this.build();
        return this.data;
    }

    addConditionForDirection( type, label, vars, direction ) {
        let con = this.addCondition( type, label, vars, true );
        direction['conditions'].push( con['@id'] );
        this.updateFromData();
        this.build();

        this.updateMsg();
    }

    addCondition( type, label, vars, skip ) {
        let con = {
            "@id": this.language_code.substring( 0, 2 ) + "-c" + Date.now().toString( 36 ),
            "@type": "Condition",
            "type": type,
            "label": label,
            "vars": vars
        }
        this.data.push( con );
        if ( skip !== true ) {
            this.updateFromData();
            this.build();
        }
        return con;
    }

    addDirection( source, target ) {
        let dir = {
            "@id": this.language_code.substring( 0, 2 ) + "-d" + Date.now().toString( 36 ),
            "@type": "Direction",
            "source": source,
            "target": target,
            "conditions": []
        }
        this.data.push( dir );
        this.updateFromData();
        this.build();
        return dir;
    }

    rmDirection( dir ) {
        this._rmNode( dir );
        // todo, remove orphaned conditions
    }

    createMsg() {
        this.addMsg();
        this.build();
    }

    getNodeById( id ) {
        return this.data.filter( node => node['@id'] == id )[0];
    }

    /**
     * Use wrapper method, because for event handlers 'this' will refer to
     * the input object
     */
    getEditEventListener() {
        let graph = this;
        let el = function( e ) {
            let parts = e.srcElement.name.split( '-' );
            let field = parts.pop();
            let id = parts.join('-');
            console.log( this, graph );
            let node = graph.getNodeById( id );
            let path = field.split( '.' ); // use vars.test to set ['vars']['test'] = value
            console.log(id, node);
            var res = node;
            for ( var i = 0; i < path.length; i++ ) {
                if ( i == ( path.length - 1 ) ) {
                    console.log( 'last', path[i] );
                    res[path[i]] = e.srcElement.value;
                } else {
                    res = res[path[i]];
                }
            }

            // node[field] = e.srcElement.value;

            graph.build();
        }
        return el;
    }

    getJsonString() {
        // recreate array to have the right order of items.
        this.data = [...this.messages, ...this.conditions,
        ...this.directions, ...this.diversions]
        let d = [];
        let toRemove = ['sourceX', 'sourceY', 'targetX', 'targetY', 'x', 'y', 'vx', 'vy']
        for ( let node of this.data ) {
            let n = {};
            console.log( node['source'] );
            for ( let e in node ) {
                if ( node.hasOwnProperty( e ) && toRemove.indexOf( e ) == -1 ) {
                    if ( this.data.indexOf( node[e] ) != -1 ) {
                        n[e] = node[e]['@id'];
                    } else {
                        n[e] = node[e];
                    }
                }
            }
            d.push( n );
        }
        return JSON.stringify( d );
    }

    downloadJson() {
        if ( !this.language_code ) {
            alert( "Make sure to load a language first" )
        }

        var blob = new Blob( [this.getJsonString()], { type: 'application/json' } );
        if ( window.navigator.msSaveOrOpenBlob ) {
            window.navigator.msSaveBlob( blob, "pillow_talk.json" );
        }
        else {
            var elem = window.document.createElement( 'a' );
            elem.href = window.URL.createObjectURL( blob );
            elem.download = "pillow_talk.json";
            document.body.appendChild( elem );
            elem.click();
            document.body.removeChild( elem );
        }
    }

    saveJson( msg_id, fileInputElement, callback ) {
        if ( !this.language_code ) {
            alert( "Make sure to load a language first" )
        }

        let formData = new FormData();

        formData.append( "language", this.language_code );

        if ( msg_id ) {
            formData.append( "message_id", msg_id );
            formData.append( "audio", fileInputElement.files[0] );
        }

        let blob = new Blob( [this.getJsonString()], { type: "application/json" } );
        formData.append( "json", blob );
        console.log( formData );
        var request = new XMLHttpRequest();
        request.open( "POST", "http://localhost:8888/upload" );
        
        if(callback) {
            request.addEventListener( "load", callback);
        }
        
        request.send( formData );
    }

    loadData( data, language_code ) {
        this.language_code = language_code;
        this.data = data;
        this.updateFromData();
        this.build( true );
    }

    updateFromData() {
        this.messages = this.data.filter(( node ) => node['@type'] == 'Msg' );
        this.directions = this.data.filter(( node ) => node['@type'] == 'Direction' );
        this.conditions = this.data.filter(( node ) => node['@type'] == 'Condition' );
        this.diversions = this.data.filter(( node ) => node['@type'] == 'Diversion' );
        
        document.getElementById('current_lang').innerHTML = "";
        document.getElementById('current_lang').appendChild(crel('span', {
            'class': 'flag-icon ' + this.language_code
        }));

        // save state;
        this.saveState();
    }
    
    updateHugveyStatus(hv) {
        let els = document.getElementsByClassName('beenHit');
        while(els.length > 0) {
            els[0].classList.remove('beenHit');
        }
        if(!hv || typeof  hv['history'] == 'undefined') {
            return;
        }
        
        for(let msg of hv['history']['messages']) {
            document.getElementById(msg[0]['id']).classList.add('beenHit');
        }
        for(let msg of hv['history']['directions']) {
            document.getElementById(msg[0]['id']).classList.add('beenHit');
        }
    }

    saveState() {
        window.localStorage.setItem( "lastState", this.getJsonString() );
    }

    hasSavedState() {
        return window.localStorage.getItem( "lastState" ) !== null;
    }

    loadFromState() {
        this.loadData( JSON.parse( window.localStorage.getItem( "lastState" ) ) );
    }

    build( isInit ) {
        this.simulation = d3.forceSimulation( this.messages )
            .force( "link", d3.forceLink( this.directions ).id( d => d['@id'] ) )
            .force( "charge", d3.forceManyBody().strength( -1000 ) )
            .force( "center", d3.forceCenter( this.width / 2, this.height / 2 ) )
            .force( "collide", d3.forceCollide( this.nodeSize * 2 ) )
            ;

        // Update existing nodes
        let node = this.nodesG
            .selectAll( "g" )
            .data( this.messages, n => n['@id'] )
            ;

        // Update existing nodes
        let newNode = node.enter();

        let newNodeG = newNode.append( "g" )
            .attr( 'id', d => d['@id'] )
            .call( d3.drag( this.simulation ) )
            .on( 'click', function( d ) {
                this.clickMsg( d );
            }.bind( this ) )
            ;
        console.log( 'a' );
        let circle = newNodeG.append( "circle" )
            .attr( 'r', this.nodeSize )
            // .text(d => d.id)
            ;
        let textId = newNodeG.append( "text" ).attr( 'class', 'msg_id' );
        let textContent = newNodeG.append( "text" ).attr( 'class', 'msg_txt' );
        let statusIcon = newNodeG.append( "image" )
            .attr( 'class', 'status_icon' )
            .attr( 'x', '-10' )
            .attr( 'y', '10' )
            .attr( 'width', '20' )
            .attr( 'height', '20' )
            ;

        // remove
        node.exit().remove();
        node = node.merge( newNodeG );

        // for all existing nodes:
        node.attr( 'class', msg => {
            let classes = [];
            if ( this.selectedMsg == msg ) classes.push( 'selectedMsg' );
            if ( msg['start'] == true ) classes.push( 'startMsg' );
            if ( this.getDirectionsFrom( msg ).length < 1 ) {
                classes.push( 'endMsg' );
                if ( this.getDirectionsTo( msg ).length < 1 ) classes.push( 'orphanedMsg' );
            }

            return classes.join( ' ' );
        } )

        let link = this.linkG
            .selectAll( "line" )
            .data( this.directions )
            ;
        let newLink = link.enter()
            .append( "line" )
            ;
        
        //remove
        link.exit().remove();
        link = link.merge( newLink );

        link.attr( 'class', l => { return `link ` + ( l['conditions'].length == 0 ? "link--noconditions" : "link--withconditions" ); } );
        link.attr('id', (l) => l['@id']);

        // console.log('c');
        let formatText = ( t ) => {
            if ( t.length > this.maxChars ) {
                return t.substr( 0, this.maxChars - 3 ) + '...';
            } else {
                return t;
            }
        };

        node.selectAll( "text.msg_id" ).text( d => d['@id'] );
        node.selectAll( "text.msg_txt" ).text( d => formatText( `${d['text']}` ) );
        node.selectAll( "image.status_icon" ).attr('xlink:href', d => d['audio'] ? '' : '/images/music-broken.svg');
        // console.log('q');
        // // TODO: update text
        // let text = newNodeG.append("text")
        //       // .attr('stroke', "black")
        //     .text(d => formatText(`(${d['@id']}) ${d['text']}`))
        //     // .attr('title', d => d.label)
        //     ;

        let n = this.nodesG;
        this.simulation.on( "tick", () => {
            link
                .each( function( d ) {
                    let sourceX, targetX, midX, dx, dy, angle;
                    // This mess makes the arrows exactly perfect.
                    // thanks to http://bl.ocks.org/curran/9b73eb564c1c8a3d8f3ab207de364bf4
                    if ( d.source.x < d.target.x ) {
                        sourceX = d.source.x;
                        targetX = d.target.x;
                    } else if ( d.target.x < d.source.x ) {
                        targetX = d.target.x;
                        sourceX = d.source.x;
                    } else if ( d.target.isCircle ) {
                        targetX = sourceX = d.target.x;
                    } else if ( d.source.isCircle ) {
                        targetX = sourceX = d.source.x;
                    } else {
                        midX = ( d.source.x + d.target.x ) / 2;
                        if ( midX > d.target.x ) {
                            midX = d.target.x;
                        } else if ( midX > d.source.x ) {
                            midX = d.source.x;
                        } else if ( midX < d.target.x ) {
                            midX = d.target.x;
                        } else if ( midX < d.source.x ) {
                            midX = d.source.x;
                        }
                        targetX = sourceX = midX;
                    }

                    dx = targetX - sourceX;
                    dy = d.target.y - d.source.y;
                    angle = Math.atan2( dx, dy );

                    // Compute the line endpoint such that the arrow
                    // is touching the edge of the node rectangle perfectly.
                    d.sourceX = sourceX + Math.sin( angle ) * this.nodeSize;
                    d.targetX = targetX - Math.sin( angle ) * this.nodeSize;
                    d.sourceY = d.source.y + Math.cos( angle ) * this.nodeSize;
                    d.targetY = d.target.y - Math.cos( angle ) * this.nodeSize;
                }.bind( this ) )
                .attr( "x1", function( d ) { return d.sourceX; } )
                .attr( "y1", function( d ) { return d.sourceY; } )
                .attr( "x2", function( d ) { return d.targetX; } )
                .attr( "y2", function( d ) { return d.targetY; } );

            node.attr( "transform", d => `translate(${d.x},${d.y})` );
            // .attr("cy", d => d.y);
        } );

        // this.simulation.alpha(1);
        // this.simulation.restart();
        if ( typeof isInit != 'undefined' && isInit ) {
            for ( let i = 0, n = Math.ceil( Math.log( this.simulation.alphaMin() ) / Math.log( 1 - this.simulation.alphaDecay() ) ); i < n; ++i ) {
                this.simulation.tick();
            }
        }
        return this.svg.node();
    }
}