// Code from http://mbostock.github.io/d3/talk/20111018/tree.html adapted, see git history for changes
(function() {
var idGenerator = 0; // Used to generate artificial ids if data.id is not set

function update(tree, vis, diagonal, source) {
	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 * 180; });

	// Update the nodes…
	var node = vis.selectAll("g.node")
			.data(nodes, function(d) { return d.id || (d.id = ++idGenerator); });

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

	nodeEnter.append("svg:circle")
			.attr("r", 1e-6)
			.style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

	nodeEnter.append("svg:text")
			.attr("x", function(d) { return d.children || d._children ? -25 : 25; })
			.attr("dy", ".35em")
			.attr("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
			.text(function(d) { return d.name; })
			.style("fill-opacity", 1e-6);

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

	nodeUpdate.select("circle") // The circle for the nodes
			.attr("r", 10)
			.style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });

	nodeUpdate.select("text")
			.style("fill-opacity", 1)
			.text(function(d) { return d.name; });

	// 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();

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

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

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

	// Enter any new links at the parent's previous position.
	link.enter().insert("svg:path", "g")
			.attr("class", "link")
			.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;
	});
}

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

function createTree(treeData, parentElSel, options) {
	var m = options.margins || [20, 120, 20, 120],
			w = (options.width || 1280) - m[1] - m[3],
			h = (options.height || 800) - m[0] - m[2];

	var tree = d3.layout.tree()
			.size([h, w]);

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

	var vis = parentElSel.append("svg:svg")
			.attr("width", w + m[1] + m[3])
			.attr("height", h + m[0] + m[2])
			.append("svg:g")
			.attr("transform", "translate(" + m[3] + "," + m[0] + ")");


	root = treeData;
	root.x0 = h / 2;
	root.y0 = 0;

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

	// Initialize the display to show all nodes.
	root.children.forEach(toggleAll);

	update(tree, vis, diagonal, root);
	return {tree: tree, vis: vis, diagonal: diagonal, root: root};
}

// Export our API
window.d3Tree = {
	createTree: createTree,
	update: function(treeObj) {
		update(treeObj.tree, treeObj.vis, treeObj.diagonal, treeObj.root);
	},
};
})();