//
//  main.js
//
//  A project template for using arbor.js
//

(function($){

    var Renderer = function(canvas){
        var canvas = $(canvas).get(0)
        var ctx = canvas.getContext("2d");
        var particleSystem

        var canvasBackground;
        var mainNode;
        var balloonNode;
        var that = {
            init:function(system){
                //
                // the particle system will call the init function once, right before the
                // first frame is to be drawn. it's a good place to set up the canvas and
                // to pass the canvas size to the particle system
                //
                // save a reference to the particle system for use in the .redraw() loop
                particleSystem = system

                // inform the system of the screen dimensions so it can map coords for us.
                // if the canvas is ever resized, screenSize should be called again with
                // the new dimensions
                particleSystem.screenSize(canvas.width, canvas.height)
                particleSystem.screenPadding(50) // leave an extra 80px of whitespace per side

                // set up some event handlers to allow for node-dragging
                that.initMouseHandling()
            },

            redraw:function(){
                //
                // redraw will be called repeatedly during the run whenever the node positions
                // change. the new positions for the nodes can be accessed by looking at the
                // .p attribute of a given node. however the p.x & p.y values are in the coordinates
                // of the particle system rather than the screen. you can either map them to
                // the screen yourself, or use the convenience iterators .eachNode (and .eachEdge)
                // which allow you to step through the actual node objects but also pass an
                // x,y point in the screen's coordinate system
                //
                ctx.fillStyle = "black"
                ctx.fillRect(0,0, canvas.width, canvas.height)
                ctx.imageSmoothingEnabled = true;

                var drawBackground = function(densityOfPoints, maxSize, minSize) {
                    if (canvasBackground) {
                        ctx.putImageData(canvasBackground, 0, 0);
                    } else {
                        minSize = minSize || 1;
                        maxSize = maxSize || 3;
                        densityOfPoints = densityOfPoints || 0.01;
                        var numberOfPoints = densityOfPoints * canvas.width * canvas.height;
                        for (var i = 0; i < numberOfPoints; i++) {
                            var size = Math.random() * (maxSize - minSize) + minSize;
                            var opacity = Math.random() * 0.2 + 0.4;
                            ctx.fillStyle = 'rgba(220, 220, 255, ' + opacity + ')';
                            ctx.beginPath();
                            ctx.arc(Math.random() * canvas.width, Math.random() * canvas.height, size / 2, 0, 2 * Math.PI);
                            ctx.fill();
                        }
                        canvasBackground = ctx.getImageData(0, 0, canvas.width, canvas.height);
                    }
                }

                drawBackground(0.02);

                // JESTEM BOGIEM PRZEKSZTAŁCEŃ 2D :O
                var drawArrow = function(pt1, pt2, length, style) {
                    var angle = Math.atan2(pt2.y - pt1.y, pt2.x - pt1.x);
                    ctx.fillStyle = style;
                    ctx.setLineDash([]);
                    ctx.lineWidth = 1;
                    ctx.beginPath();
                    ctx.moveTo(pt2.x, pt2.y);
                    ctx.lineTo(pt2.x - length * Math.cos(angle - Math.PI/6), pt2.y - length * Math.sin(angle - Math.PI/6));
                    ctx.lineTo(pt2.x - length * (Math.cos(angle + Math.PI/6) + Math.cos(angle - Math.PI/6))/3,
                               pt2.y - length * (Math.sin(angle - Math.PI/6) + Math.sin(angle + Math.PI/6))/3);
                    ctx.lineTo(pt2.x - length * Math.cos(angle + Math.PI/6), pt2.y - length * Math.sin(angle + Math.PI/6));
                    ctx.lineTo(pt2.x, pt2.y);
                    ctx.stroke();
                    ctx.fill();
                }

                var detectDestination = function(pt1, pt2, imageBox) {
                    var destination = {};
                    var intersectingSegment = undefined;
                    if (pt1.x != pt2.x) {
                        var lineSlope = (pt1.y - pt2.y) / (pt1.x - pt2.x);
                        var width = imageBox.width;
                        var height = imageBox.height;
                        if ((-height / 2  <= lineSlope * width / 2)
                            && (lineSlope * width / 2 <= height / 2)) {
                            if (pt1.x > pt2.x) {
                                intersectingSegment = [
                                    { x: pt2.x + width / 2,
                                      y: pt2.y - height / 2 },
                                    { x: pt2.x + width / 2,
                                      y: pt2.y + height / 2 }
                                ];
                            }
                            else {
                                intersectingSegment = [
                                    { x: pt2.x - width / 2,
                                      y: pt2.y - height / 2 },
                                    { x: pt2.x - width / 2,
                                      y: pt2.y + height / 2 }
                                ];
                            }
                        }
                        if ((-width / 2 <= (height / 2) / lineSlope)
                            && ((height / 2) / lineSlope <= width / 2)) {
                            if (pt1.y > pt2.y) {
                                intersectingSegment = [
                                    { x: pt2.x - width / 2,
                                      y: pt2.y + height / 2 },
                                    { x: pt2.x + width / 2,
                                      y: pt2.y + height / 2 }
                                ];
                            }
                            else {
                                intersectingSegment = [
                                    { x: pt2.x - width / 2,
                                      y: pt2.y - height / 2 },
                                    { x: pt2.x + width / 2,
                                      y: pt2.y - height / 2 }
                                ];
                            }
                        }
                    }
                    else {
                        intersectingSegment = (pt1.y > pt2.y) ? [
                            { x: pt2.x - width / 2,
                              y: pt2.y - height / 2 },
                            { x: pt2.x + width / 2,
                              y: pt2.y - height / 2 }
                        ] : [
                            { x: pt2.x - width / 2,
                              y: pt2.y + height / 2 },
                            { x: pt2.x + width / 2,
                              y: pt2.y + height / 2 }
                        ];
                    }
                    if (intersectingSegment) {
                        var intersectAngle = ((intersectingSegment[1].y - intersectingSegment[0].y) * (pt2.x - pt1.x))
                            - ((intersectingSegment[1].x - intersectingSegment[0].x) * (pt2.y - pt1.y));
                        var aSlope = pt1.y - intersectingSegment[0].y;
                        var bSlope = pt1.x - intersectingSegment[0].x;
                        var numerator1 = ((intersectingSegment[1].x - intersectingSegment[0].x) * aSlope)
                            - ((intersectingSegment[1].y - intersectingSegment[0].y) * bSlope);
                        var intersectSlope = numerator1 / intersectAngle;
                        destination = { x: pt1.x + (intersectSlope * (pt2.x - pt1.x)),
                                        y: pt1.y + (intersectSlope * (pt2.y - pt1.y)) };
                    }
                    return destination;
                }

                var setOpacity = function(color, opacity) {
                    if (color.substring(0, 5) == 'rgba(') {
                        color = color.replace(/,[^,]*\)$/, ',' + opacity + ')');
                    }
                    return color;
                }

                var drawEdge = function(edge, pt1, pt2) {
                    // edge: {source:Node, target:Node, length:#, data:{}}
                    // pt1:  {x:#, y:#}  source position in screen coords
                    // pt2:  {x:#, y:#}  target position in screen coords

                    ctx.strokeStyle = edge.data.style || "rgba(255,255,255,.333)"
                    ctx.lineWidth = edge.data.width || 3
                    ctx.setLineDash(edge.data.dash || [])

                    // draw a line from pt1 to pt2
                    ctx.beginPath()
                    ctx.moveTo(pt1.x, pt1.y)

                    if (edge.data.arrow) {
                        if (edge.target.data.imageObject) {
                            var destination = detectDestination(pt1, pt2, edge.target.data.imageObject);
                            if (destination) {
                                pt2 = destination;
                            }
                        }
                    }

                    if (mainNode && balloonNode) {
                        if (edge.source.data.balloon || edge.target.data.balloon ||
                            (balloonNode != mainNode
                             && particleSystem.getEdgesTo(balloonNode)[0].source == edge.target
                             && edge.source == mainNode)) {
                            ctx.strokeStyle = setOpacity(edge.target.data.color, 0.8);
                        }
                    }

                    ctx.lineTo(pt2.x, pt2.y);
                    ctx.stroke();
                    if (edge.data.arrow) {
                        drawArrow(pt1, pt2, edge.data.arrow, ctx.strokeStyle);
                    }
                };

                var drawImage = function(image, coords, color, strokeColor) {
                    if (!image.height) {
                        image.height = image.width ? image.width * image.naturalHeight / image.naturalWidth : image.naturalHeight;
                    }
                    if (!image.width) {
                        image.width = image.height ? image.height * image.naturalWidth / image.naturalHeight : image.naturalWidth;
                    }
                    ctx.save();
                    var color = color || 'black';
                    ctx.fillStyle = color;
                    ctx.lineWidth = 5;
                    ctx.beginPath();
                    ctx.arc(coords.x, coords.y, image.width / 2, 0, Math.PI * 2);
                    ctx.clip();
                    ctx.drawImage(image,
                                  coords.x - image.width / 2,
                                  coords.y - image.height / 2,
                                  image.width,
                                  image.height);
                    ctx.fill();
                    ctx.restore();
                    ctx.lineWidth = 3;
                    ctx.strokeStyle = strokeColor;
                    ctx.beginPath();
                    ctx.arc(coords.x, coords.y, image.width / 2, 0, Math.PI * 2);
                    ctx.stroke();
                };

                var repositionBalloon = function(div, node) {
                    var topOffset = node.data.p.y - node.data.height / 2;
                    if (topOffset < 0) {
                        topOffset = 0;
                    }
                    if (topOffset + div.outerHeight() > $(window).height()) {
                        topOffset = $(window).height() - div.outerHeight();
                    }
                    var leftMargin = node.data.width / 2 + 2;
                    if (mainNode && node.data.p.x < mainNode.data.p.x) {
                        leftMargin = -leftMargin - div.outerWidth();
                    }
                    var leftOffset = node.data.p.x + leftMargin;
                    if (leftOffset < 0) {
                        leftOffset += div.outerWidth() + node.data.width + 4;
                    }
                    if (leftOffset + div.outerWidth() > $(window).width()) {
                        leftOffset -= div.outerWidth() + node.data.width + 4;
                    }
                    div.css('top', topOffset);
                    div.css('left', leftOffset);
                    div.show();
                }

                var currentZIndex = 0;
                var drawNode = function(node, pt){
                    // node: {mass:#, p:{x,y}, name:"", data:{}}
                    // pt:   {x:#, y:#}  node position in screen coords

                    node.data.p = pt;
                    node.data.zindex = currentZIndex++;
                    if (node.data.main) {
                        mainNode = node;
                        if (history.replaceState) {
                            history.replaceState(null, null, '#' + node.name);
                        }
                    }

                    if (node.data.image && node.data.width > 10) {
                        var isHighlighted = function(node) {
                            if (node.data.balloon) {
                                return true;
                            }
                            if (balloonNode && mainNode) {
                                if (node == mainNode) {
                                    return true;
                                }
                                var targets = particleSystem.getEdgesFrom(node);
                                for (var t = 0; t < targets.length; t++) {
                                    if (targets[t].target == balloonNode) {
                                        return true;
                                    }
                                }
                            }
                        }
                        var strokeColor = isHighlighted(node) ? setOpacity(node.data.color, 0.8) : 'rgba(255, 255, 255, 0.7)';
                        if (node.data.imageObject) {
                            node.data.imageObject.width = node.data.width;
                            node.data.imageObject.height = node.data.height;
                            drawImage(node.data.imageObject, pt, node.data.color, strokeColor);
                        } else {
                            var img = new Image(node.data.width, node.data.height);
                            img.onload = function() {
                                node.data.imageObject = img;
                                drawImage(node.data.imageObject, pt, node.data.color, strokeColor);
                            };
                            img.src = '_img/' + node.data.image;
                        }
                    } else {
                        var color = node.data.color || 'black';
                        ctx.fillStyle = color;
                        ctx.lineWidth = 5;
                        ctx.strokeStyle = 'rgba(255,255,255,0.33)';
                        ctx.beginPath();
                        ctx.arc(pt.x, pt.y, node.data.width / 2, 0, Math.PI*2);
                        ctx.stroke();
                        ctx.fill();
                    }

                    if (node.data.balloon) {
                        repositionBalloon(node.data.balloon, node);
                        if (node.data.oldWidth) {
                            node.data.width = node.data.oldWidth;
                        }
                        if (node.data.oldHeight) {
                            node.data.height = node.data.oldHeight;
                        }
                        balloonNode = node;
                    }
                };

                particleSystem.eachEdge(drawEdge);
                particleSystem.eachNode(drawNode);
                if (balloonNode) {
                    var selectedDimension = Math.max((balloonNode.data.image) ? 100 : 50, balloonNode.data.width);
                    balloonNode.data.oldWidth = balloonNode.data.width;
                    balloonNode.data.width = selectedDimension;
                    balloonNode.data.oldHeight = balloonNode.data.height;
                    balloonNode.data.height = selectedDimension;
                    drawNode(balloonNode, balloonNode.data.p);
                }
            },

            initMouseHandling:function(){
                var hideBalloon = function() {
                    if (balloon) {
                        balloon.data('node').data.balloon = undefined;
                        balloon.remove();
                        balloon = undefined;
                        balloonNode = undefined;
                    }
                }
                var fixedNodes = 0;
                var moveNode = function(node, newNode, duration) {
                    var steps = 20;
                    duration = duration || 1000;
                    var xStep = (newNode.x - node.p.x) / steps;
                    var yStep = (newNode.y - node.p.y) / steps;
                    var originalPosition = { x: node.p.x,
                                             y: node.p.y };
                    for (var step = 0; step < steps; step++) {
                        setTimeout(
                            function(i) {
                                return function() {
                                    node.p = { x: originalPosition.x + xStep * i,
                                               y: originalPosition.y + yStep * i };
                                    if (i == steps - 1) {
                                        fixedNodes--;
                                    }
                                }
                            }(step),
                            step * duration / steps
                        );
                    }
                }
                var switchContext = function() {
                    var link = $(this);
                    hideBalloon();
                    $.getJSON(
                        '_data/' + link.attr('data-link') + '.json?' + (new Date()).getTime(),
                        function(newGraph) {
                            fixedNodes = 0;
                            particleSystem.prune(function(node) {
                                if (node.data.main) {
                                    node.fixed = false;
                                }
                                if (newGraph.nodes[node.name]) {
                                    node.fixed = true;
                                    node.data.mass = node.mass;
                                    node.tempMass = 10000;
                                    fixedNodes++;
                                    moveNode(node, newGraph.nodes[node.name], 1500);
                                    return false;
                                } else {
                                    node.tempMass = 0.001;
                                    return true;
                                }
                            });
                            var mergeInterval = setInterval(function() {
                                if (fixedNodes == 0) {
                                    particleSystem.merge(newGraph);
                                    particleSystem.prune(function(node) {
                                        node.tempMass = node.mass;
                                        return false;
                                    });
                                    clearInterval(mergeInterval);
                                }
                            }, 100);
                        }
                    );

                }
                var balloon;
                // start listening
                $(canvas).click(function(e) {
                    hideBalloon();
                    var pos = $(canvas).offset();
                    _mouseP = arbor.Point(e.pageX-pos.left, e.pageY-pos.top)
                    var candidateNode = undefined;
                    particleSystem.eachNode(function(node) {
                        var distance = _mouseP.subtract(particleSystem.toScreen(node.p));
                        if (Math.sqrt(distance.x*distance.x + distance.y*distance.y) <= node.data.width / 2 + 3) {
                            if (!candidateNode || candidateNode.data.zindex < node.data.zindex) {
                                candidateNode = node;
                            }
                        }
                    });
                    if (candidateNode) {
                        balloon = $('<div>');
                        balloon.css({
                            'position': 'absolute',
                            'background': 'rgba(0,0,0,0.45)', 'color': 'red',
                            'max-width': '150px',
                            'max-height': '150px',
                            'overflow': 'hidden',
                            'padding': '5px',
                            'border': 'solid 2px white',
                            'border-radius': '5px'
                        });
                        balloon.append($('<h1>').text(candidateNode.data.name));
                        if (!candidateNode.data.main) {
                            var switchLink = $('<a>').attr({
                                'href': '#',
                                'data-link': candidateNode.name
                            });
                            switchLink.text('[go!]');
                            switchLink.click(switchContext);
                            balloon.append(switchLink);
                        }
                        balloon.hide();
                        $('body').append(balloon);
                        balloon.data('node', candidateNode);
                        candidateNode.data.balloon = balloon;
                    }
                });
            },

        }
        return that
    }

    var sys;
    $(document).ready(function() {
        var graphID = 'graph';
        if (location.hash) {
            graphID = location.hash.replace(/^#/, '');
        }
        $.getJSON('_data/' + graphID + '.json', function(graph) {
            graph.repulsion = graph.repulsion || 20;
            graph.stiffness = graph.stiffness || 1;
            graph.friction = graph.friction || 0.99;
            graph.gravity = graph.gravity || true;
            graph.fps = graph.fps || 10;
            graph.precision = graph.precision || 0.1;
            graph.dt = graph.dt || 0.11;
            sys = arbor.ParticleSystem(graph.repulsion, graph.stiffness, graph.friction, graph.gravity, graph.fps, graph.dt, graph.precision);
            sys.renderer = Renderer("#viewport"); // our newly created renderer will have its .init() method called shortly by sys...
            $(window).trigger('resize');
            sys.graft(graph);
        });
        $(window).resize(function() {
            var width = $(window).width() - 5;
            var height = $(window).height() - 5;
            $('#viewport').attr({'width': width,
                                 'height': height});
            sys.screenSize(width, height);
        });
    })

})(this.jQuery)