// material colors
var
    //              50         100       200        300        400        500       
    pDeepPurple = ['#ede7f6', '#d1c4e9', '#b39ddb', '#9575cd', '#7e57c2', '#673ab7',
    //              600        700        800       900
                   '#5e35b1', '#512da8', '#4527a0', '#311b92',
    //              A100      A200        A400       A700
                   '#b388ff', '#7c4dff', '#651fff', '#6200ea'],
    //         A100       A200       A400       A700
    pGreen = ['#b9f6ca', '#69f0ae', '#00e676', '#00c853'],
    pDark = ['#000000', '#212121', '#303030', '#424242'],
    pLight = ['#E0E0E0', '#F5F5F5', '#FAFAFA', '#FFFFFF'],

    primaryColor = [pDeepPurple[1], pDeepPurple[5], pDeepPurple[7]],
    secondaryColor = pGreen[3],
    themeColor = pLight,

    accentColor = secondaryColor,
    bgColor = themeColor[3],

    linkColor = primaryColor[0],
    linkHighlightColor = primaryColor[1],
    nodeColor = primaryColor[1],
    nodeHighlightColor = primaryColor[2],
    nodeSelectionColor = accentColor
;


/* network construction */

var Network = (function() {
    function Network(layout) {
        this.layout = layout;
    }

    Network.prototype.init = function() {
        this._createNodes();
        this._createLinks();
    };

    Network.prototype.resize = function(env) {
        var largestLayerSize = 0;
        for (layer=0; layer<this.layout.net.layers; layer++) {
            if (this.layout.net[layer].size > largestLayerSize) largestLayerSize = this.layout.net[layer].size;
        }
        this.responsiveRadius = d3.min([env.width, env.height]) / d3.max([this.layout.net.layers, largestLayerSize]);
        this._updateNodes(env);
    };

    Network.prototype._createNodes = function() {
        // create layers
        this.nodes = [];
        for (layer=0; layer<this.layout.net.layers; layer++) {
            for (node=0; node<this.layout.net[layer].size; node++) {
                this.nodes.push({
                    id: layer.toString() + "_" + node.toString(),
                    layer: layer,
                    fixed: true
                });
            }
        }
    };

    Network.prototype._createLinks = function() {
        this.links = [];
        var nodesMap = d3.map();
        this.nodes.forEach(function (n) {
            return nodesMap.set(n.id, n);
        });
        // create links between adjacent layers
        for (layer=0; layer<this.layout.net.layers-1; layer++) { // for every layer except the last
            for (src=0; src<this.layout.net[layer].size; src++) { // get all nodes
                if (this.layout.net[layer].isBias) {
                    this.links.push({ // in case of a bias layer, connect 1:1
                        source: nodesMap.get(layer.toString() + "_" + src.toString()),
                        target: nodesMap.get((layer+1).toString() + "_" + src.toString()),
                        weight: 1
                    });
                } else { // normal layer
                    for (tar=0; tar<this.layout.net[layer+1].size; tar++) { // get all nodes of the next layer
                        this.links.push({ // connect both nodes
                            source: nodesMap.get(layer.toString() + "_" + src.toString()),
                            target: nodesMap.get((layer+1).toString() + "_" + tar.toString()),
                            weight: 1
                        });
                    }
                }
            }
        }
    };

    Network.prototype._updateNodes = function(env) {
        biasLayers = 0;
        for (layer=0; layer<this.layout.net.layers; layer++) {
            if (this.layout.net[layer].isBias) biasLayers++;
        }
        var cnt = 0;
        for (layer=0; layer<this.layout.net.layers; layer++) {
            for (node=0; node<this.layout.net[layer].size; node++) {
                // dynamic ("responsive") attributes for all window sizes
                if (this.layout.net[layer].isBias) {
                    this.nodes[cnt].x = (layer - biasLayers + 1.25) * (env.width / (this.layout.net.layers - biasLayers));
                    this.nodes[cnt].y = (node + 0.25) * (env.height / this.layout.net[layer].size);
                    this.nodes[cnt].r = this.responsiveRadius * 0.2;
                } else {
                    this.nodes[cnt].x = (layer - biasLayers + 0.5) * (env.width / (this.layout.net.layers - biasLayers));
                    this.nodes[cnt].y = (node + 0.5) * (env.height / this.layout.net[layer].size);
                    this.nodes[cnt].r = this.responsiveRadius * 0.3;
                }
                cnt++;
            }
        }
    };

    Network.prototype.updateWeights = function(weights, epochLayout) { // TODO negative weights!?!
        var cnt = 0;
        for (layer=0; layer<weights.length; layer++) {
            for (layer2=0; layer2<weights[layer].length; layer2++) {
                for (node=0; node<weights[layer][layer2].length; node++) {
                    // scaled = (x - min) / (max - min)
                    var scaled = (weights[layer][layer2][node] - epochLayout.min) / (epochLayout.max - epochLayout.min);
                    this.links[cnt++].weight = scaled;
                }
            }
        }
    };

    return Network;
})();


/* data handling */

var Loader = (function() {
    function Loader() {
    }

    Loader.prototype.load = function(url, callback) {
        var self = this;
        d3.json(url)
            .get(function(e, json) {
                if (e) console.log(e);
                self._parse(json);
        });
        this._finished = callback;
    };

    Loader.prototype._parse = function(json) {
        // json format:
        // json.
        //   [batch][epoch] [[sourceIndex x targetIndex]] (int)
        // careful - root and first level nodes are objects and have no '.length'

        var layout = {};
        // layout format:
        // layout.
        //   net.layers (int)
        //   net.[net.layers].
        //      isBias (bool)
        //      size (int)
        //   layers.[batch][epoch].
        //      min (int)
        //      max (int)
        //   data.
        //      batches (int)
        //      epochs  (int)
        layout.data = {};
        layout.data.batches = Object.keys(json).length;
        layout.data.epochs  = Object.keys(json[0]).length;
        layout.net = {};
        // network structure
        layout.net.layers = json[0][0].length;
        for (layer=0; layer<layout.net.layers; layer++) {
            layerObj = {};
            if (json[0][0][layer].length == 1) { // bias
                layerObj.isBias = true;
                layerObj.size = json[0][0][0][layer].length; // workaround - Matrix should be rotatet serverside
            } else {
                layerObj.isBias = false;
                layerObj.size = json[0][0][layer].length;
            }
            layout.net[layer] = layerObj;
        }
        layout.net[layout.net.layers] = {'isBias': false, 'size': json[0][0][layout.net.layers-1][0].length};
        layout.net.layers += 1; // output layer
        // layer properties
        layout.layers = {};
        for (batch=0; batch<layout.data.batches; batch++) {
            layout.layers[batch] = {};
            for (epoch=0; epoch<layout.data.epochs; epoch++) {
                layout.layers[batch][epoch] = {};
                layout.layers[batch][epoch].max = 0;
                layout.layers[batch][epoch].min = Infinity;
                for (layer=0; layer<json[batch][epoch].length; layer++) {
                    var layerMin = d3.min(json[batch][epoch][layer]);
                    var layerMax = d3.max(json[batch][epoch][layer]);
                    if (layerMin < layout.layers[batch][epoch].min) layout.layers[batch][epoch].min = layerMin;
                    if (layerMax > layout.layers[batch][epoch].max) layout.layers[batch][epoch].max = layerMax;
                }
            }
        }
        if (this._finished) this._finished(layout, json);
    };

    return Loader;
})();


/* animation stepping */

var Animator = (function() {
    function Animator(layout, time, step) {
        this.layout = layout;
        this.step = step;
        this.frameDuration = time / (this.layout.data.batches * this.layout.data.epochs / this.step);
    }

    Animator.prototype.start = function(bat, ep, callback, finishedCb) {
        var self = this;
        this.epoch = ep;
        this.batch = bat;
        this.finishedCb = finishedCb;
        wrapper = function() {
            callback(self.batch, self.epoch, self.frameDuration);
            self.animate();
        };
        this.pid = setInterval(wrapper, this.frameDuration);
    };

    Animator.prototype.stop = function() {
        if (this.finishedCb) this.finishedCb();
        clearInterval(this.pid);
    };

    Animator.prototype.animate = function() {
        this.epoch += this.step;
        if (this.epoch >= this.layout.data.epochs) {
            this.epoch = 0;
            if (++this.batch>= this.layout.data.batches) {
                this.batch = 0;
                this.stop();
            }
        }
    };

    return Animator;
})();


/* main */

var Visualizer = (function() {
    var _weightScaler = 10; // size of thickest line

    function Visualizer(svg) {
        this.loader = new Loader();
        this.svg = svg;
        this.stepHooks = [];
        this.stopHooks = [];
    }

    Visualizer.prototype.getSteps = function() {
        return this.layout.data.batches * this.layout.data.epochs;
    };
    Visualizer.prototype.getDatashape = function() {
        return this.layout.data;
    };

    Visualizer.prototype.load = function(url, callback) {
        var self = this;
        function wrapper(layout, data) {
            self.layout = layout;
            self.data = data;
            self._setup();
            callback();
        }
        this.loader.load("data/log.json", wrapper);
    };

    Visualizer.prototype.stopAnimation = function() {
        this.animator.stop();
    };

    Visualizer.prototype.animate = function(animationTime, resolution, step) {
        // animationTime in seconds per frame
        // resolution in epochs per frame
        var self = this;
        var batch = Math.floor(step / this.layout.data.epochs),
            epoch = step % this.layout.data.epochs;
        this.animator = new Animator(this.layout, animationTime * 1000, resolution);
        this.animator.start(batch, epoch, function(cbatch, cepoch) {
            self.show(cbatch, cepoch);
        }, function() {
            self.stopHooks.forEach(function(hook){ hook(); });
        });
    };

    Visualizer.prototype.hookStepper = function(hook) {
        this.stepHooks.push(hook);
    };

    Visualizer.prototype.hookStop = function(hook) {
        this.stopHooks.push(hook);
    };

    Visualizer.prototype.showStep = function(step) {
        var epoch = step % this.layout.data.epochs,
            batch = Math.floor(step / this.layout.data.epochs);
        this.show(batch, epoch);
    };

    Visualizer.prototype.show = function(batch, epoch, transitionDuration) {
        var self = this;
        this.network.updateWeights(this.data[batch][epoch], this.layout.layers[batch][epoch]);
        if (transitionDuration) {
            // 10% extra time per frame for the code execution
            this.domLink
                .transition()
                .duration(transitionDuration / 1.1);
        }
        this.domLink.style("stroke-width", function(d) { return d.weight * _weightScaler; });
        this.stepHooks.forEach(function(hook){ hook(batch * self.layout.data.epochs + epoch); });
    };

    Visualizer.prototype.reposition = function() {
        var width = parseInt(this.svg.style("width"))   || 800,
            height = parseInt(this.svg.style("height")) || 600;
        var node = this.svg.selectAll(".node");

        this.network.resize({"width": width, "height": height});

        node
            .attr("cx", function(d) { return d.x; })
            .attr("cy", function(d) { return d.y; })
            .attr("r",  function(d) { return d.r; });
        this.domLink
            .attr("x1", function(d) { return d.source.x; })
            .attr("y1", function(d) { return d.source.y; })
            .attr("x2", function(d) { return d.target.x; })
            .attr("y2", function(d) { return d.target.y; });
    };

    Visualizer.prototype._setup = function() {
        var self = this;
        // create empty elements and determine the visualisation's size
        var width = parseInt(this.svg.style("width"))   || 800,
            height = parseInt(this.svg.style("height")) || 600;

        this.network = new Network(this.layout);
        this.network.init();
        this.network.resize({"width": width, "height": height});
        this.network.updateWeights(this.data[0][0], this.layout.layers[0][0]);

        this.domLink = this.svg.selectAll(".link")
            .data(this.network.links)
            .enter().append("line")
            .attr("class", function(d) { return "link source-" + d.source.id + " target-" + d.target.id; })
            .style("stroke", linkColor)
            .style("stroke-width", function(d) { return d.weight * _weightScaler; })
            .on("mouseover", function(d) {
                d3.select("#node-" + d.source.id).style("fill", nodeHighlightColor);
                d3.select("#node-" + d.target.id).style("fill", nodeHighlightColor);
                d3.select(this).style("stroke", linkHighlightColor); 
            })
            .on("mouseout", function(d) {
                var src = d3.select("#node-" + d.source.id);
                if (src.attr("data-highlight") != "true") src.style("fill", nodeColor);
                var tar = d3.select("#node-" + d.target.id);
                if (tar.attr("data-highlight") != "true") tar.style("fill", nodeColor);
                var me = d3.select(this);
                if (me.attr("data-highlight") != "true") me.style("stroke", linkColor);
            });
        var node = this.svg.selectAll(".node")
            .data(this.network.nodes)
            .enter().append("circle")
            .attr("class", function(d) { return "node layer-" + d.layer; })
            .attr("id", function(d) { return "node-" + d.id; })
            .style("fill", nodeColor)
            .style("stroke-width", 0)
            .style("stroke", nodeSelectionColor)
            .on("mouseover", function(d) {
                d3.selectAll(".source-" + d.id).style("stroke", linkHighlightColor);
                d3.selectAll(".target-" + d.id).style("stroke", linkHighlightColor);
                d3.select(this).style("fill", nodeHighlightColor);
            })
            .on("mouseout", function(d) {
                d3.selectAll(".source-" + d.id)[0].forEach(function (el) {
                    var src = d3.select(el);
                    if (src.attr("data-highlight") != "true") src.style("stroke", linkColor);
                });
                d3.selectAll(".target-" + d.id)[0].forEach(function (el) {
                    var tar = d3.select(el);
                    if (tar.attr("data-highlight") != "true") tar.style("stroke", linkColor);
                });
                var me = d3.select(this);
                if (me.attr("data-highlight") != "true") me.style("fill", nodeColor);
            })
            .on("click", function(d) {
                var me = d3.select(this);
                if (me.attr("data-highlight") == "true") {
                    d3.selectAll(".source-" + d.id).attr("data-highlight", "false");
                    //d3.selectAll(".target-" + d.id).attr("data-highlight", "false");
                    me.attr("data-highlight", "false")
                      .style("stroke-width", 0);
                } else {
                    d3.selectAll(".source-" + d.id).attr("data-highlight", "true");
                    //d3.selectAll(".target-" + d.id).attr("data-highlight", "true");
                    me.attr("data-highlight", "true")
                      .style("stroke-width", d.r / 2);
                }
            });

        this.reposition();
    };

    return Visualizer;
})();