/* ------------------------------------------------------------------------------
 *
 *  # D3.js - collapsible tree layout
 *
 *  Demo of tree layout setup with collapsible nodes
 *
 * ---------------------------------------------------------------------------- */


// Setup module
// ------------------------------

var D3TreeCollapsible = function() {


    //
    // Setup module components
    //

    // Chart
    var _treeCollapsible = function() {
        if (typeof d3 == 'undefined') {
            console.warn('Warning - d3.min.js is not loaded.');
            return;
        }

        // Main variables
        var element = document.getElementById('d3-tree-collapsible'),
            height = 800;


        // Initialize chart only if element exsists in the DOM
        if(element) {

            // Basic setup
            // ------------------------------

            // Define main variables
            var d3Container = d3.select(element),
                margin = {top: 0, right: 0, bottom: 0, left: 40},
                width = d3Container.node().getBoundingClientRect().width - margin.left - margin.right,
                height = height - margin.top - margin.bottom - 5,
                i = 0,
                root;

            // Colors
            var color = '#2196F3';



            // Create chart
            // ------------------------------

            // Add SVG element
            var container = d3Container.append("svg");

            // Add SVG group
            var svg = container
                .attr("width", width + margin.left + margin.right)
                .attr("height", height + margin.top + margin.bottom)
                .append("g")
                    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");



            // Construct chart layout
            // ------------------------------

            // Tree
            var tree = d3.layout.tree()
                .size([height, width - 180]);

            // Diagonal projection
            var diagonal = d3.svg.diagonal()
                .projection(function(d) { return [d.y, d.x]; });



            // Load data
            // ------------------------------

            d3.json("../../../../global_assets/demo_data/d3/tree/tree_data_collapsible.json", function(error, json) {

                root = json;
                root.x0 = height/2;
                root.y0 = 0;

                // Toggle nodes function
                function toggleAll(d) {
                    if (d.children) {
                        d.children.forEach(toggleAll);
                        toggle(d);
                    }
                }

                // Initialize the display to show a few nodes
                root.children.forEach(toggleAll);
                toggle(root.children[1]);
                toggle(root.children[1].children[2]);
                toggle(root.children[9]);
                toggle(root.children[9].children[0]);

                update(root);
            });



            // Layout setup
            // ------------------------------

            // Update nodes
            function update(source) {

                // Set duration
                var duration = d3.event && d3.event.altKey ? 5000 : 500;

                // Compute the new tree layout.
                var nodes = tree.nodes(root).reverse();

                // Normalize for fixed-depth.
                //nodes.forEach(function(d) { d.y = d.depth * 250; });

                // Update the nodes…
                var node = svg.selectAll(".d3-tree-node")
                    .data(nodes, function(d) { return d.id || (d.id = ++i); });


                // Enter nodes
                // ------------------------------

                // Enter any new nodes at the parent's previous position.
                var nodeEnter = node.enter().append("g")
                    .attr("class", "d3-tree-node")
                    .attr("transform", function(d) { return "translate(" + source.y0 + "," + source.x0 + ")"; })
                    .on("click", function(d) { toggle(d); update(d); });

                // Add node circles
                nodeEnter.append("circle")
                    .attr("class", "d3-line-circle")
                    .attr("r", 1e-6)
                    .style("stroke", color)
                    .style("stroke-width", 1.5)
                    .style("cursor", "pointer")
                    .style("fill", function(d) { return d._children && color; });

                // Add nodes text
                nodeEnter.append("text")
                    .attr("class", "d3-text")
                    .attr("x", function(d) { return d.children || d._children ? -10 : 10; })
                    .attr("dy", ".35em")
                    .style("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
                    .style("font-size", 12)
                    .style("fill-opacity", 1e-6)
                    .text(function(d) { return d.name; });


                // Update nodes
                // ------------------------------

                // Transition nodes to their new position.
                var nodeUpdate = node.transition()
                    .duration(duration)
                    .attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });

                // Update circle
                nodeUpdate.select("circle")
                    .attr("r", 4.5)
                    .style("fill", function(d) { return d._children && color; });

                // Update text
                nodeUpdate.select("text")
                    .style("fill-opacity", 1);


                // Exit nodes
                // ------------------------------

                // Transition exiting nodes to the parent's new position.
                var nodeExit = node.exit()
                    .transition()
                        .duration(duration)
                        .attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
                        .remove();

                // Update circles
                nodeExit.select("circle")
                    .attr("r", 1e-6);

                // Update text
                nodeExit.select("text")
                    .style("fill-opacity", 1e-6);


                // Links
                // ------------------------------

                // Update the links…
                var link = svg.selectAll(".d3-tree-link")
                    .data(tree.links(nodes), function(d) { return d.target.id; });

                // Enter any new links at the parent's previous position.
                link.enter().insert("path", "g")
                    .attr("class", "d3-tree-link d3-line-connect")
                    .style("fill", "none")
                    .style("stroke-width", 1.5)
                    .attr("d", function(d) {
                        var o = {x: source.x0, y: source.y0};
                        return diagonal({source: o, target: o});
                    })
                    .transition()
                        .duration(duration)
                        .attr("d", diagonal);

                // Transition links to their new position.
                link.transition()
                    .duration(duration)
                    .attr("d", diagonal);

                // Transition exiting nodes to the parent's new position.
                link.exit().transition()
                    .duration(duration)
                    .attr("d", function(d) {
                    var o = {x: source.x, y: source.y};
                        return diagonal({source: o, target: o});
                    })
                    .remove();

                // Stash the old positions for transition.
                nodes.forEach(function(d) {
                    d.x0 = d.x;
                    d.y0 = d.y;
                });


                // Resize chart
                // ------------------------------

                // Call function on window resize
                window.addEventListener('resize', resize);

                // Call function on sidebar width change
                var sidebarToggle = document.querySelector('.sidebar-control');
                sidebarToggle && sidebarToggle.addEventListener('click', resize);


                // Resize function
                // 
                // Since D3 doesn't support SVG resize by default,
                // we need to manually specify parts of the graph that need to 
                // be updated on window resize
                function resize() {

                    // Layout variables
                    width = d3Container.node().getBoundingClientRect().width - margin.left - margin.right,
                    nodes = tree.nodes(root),
                    links = tree.links(nodes);

                    // Layout
                    // -------------------------

                    // Main svg width
                    container.attr("width", width + margin.left + margin.right);

                    // Width of appended group
                    svg.attr("width", width + margin.left + margin.right);


                    // Tree size
                    tree.size([height, width - 180]);

                    diagonal.projection(function(d) { return [d.y, d.x]; });


                    // Chart elements
                    // -------------------------

                    // Link paths
                    svg.selectAll(".d3-tree-link").attr("d", diagonal)

                    // Node paths
                    svg.selectAll(".d3-tree-node").attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });
                }
            }

            // Toggle childrens
            function toggle(d) {
                if (d.children) {
                    d._children = d.children;
                    d.children = null;
                }
                else {
                    d.children = d._children;
                    d._children = null;
                }
            }
        }
    };


    //
    // Return objects assigned to module
    //

    return {
        init: function() {
            _treeCollapsible();
        }
    }
}();


// Initialize module
// ------------------------------

document.addEventListener('DOMContentLoaded', function() {
    D3TreeCollapsible.init();
});
