var margin = {top: 0, right: 0, bottom: 0, left: 0},
    width = 960, 
    height = 500, 
    diameter = Math.min(width, height),
    radius = diameter / 2;

var tree = d3.layout.balloon()
  .size([width, height])
  .value(function(d) { return d.size; })
  .gap(function(d) { return d.externalLinkCount * 50; });

var bundle = d3.layout.bundle();

var vis = d3.select("#vis").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + (margin.left + radius) + "," + (margin.top + radius) + ")");

var nodes, 
    node,
    links, 
    nodeData,
    linkData,
    data;

function draw() {
  var line = d3.svg.line()
      .interpolate("bundle")
      .tension(0.95)
      .x(function(d) { return d.lx; })
      .y(function(d) { return d.ly; });
  
  var link = vis.selectAll("path.link")
      .data(links);

  link.enter().append("path")
    .attr("class", "link");

  d3.selectAll("path.link")
    .transition()
    .duration(1500)
    .attr("d", line);

  node = vis.selectAll("circle.node")
    .data(nodes, function(d) { return d.name; });

  node.enter().append("circle")
    .attr("class", "node");

  d3.selectAll("circle.node")
    .transition()
    .duration(1500)
    .attr("r", function(d) { return d.r; })
    .attr("cx", function(d) { return d.x; })
    .attr("cy", function(d) { return d.y; });
}

function resetLayout() {
  nodes = tree.nodes(nodeData);
  links = bundle(linkData); 
}

function randInt(from, to) { 
  return Math.floor(from + Math.random() * (to - from + 1)); 
}

function flipCoin(tosses) { 
  return Math.floor(Math.random() * 2 * (tosses || 1)) == 1; 
}

function pickRandomNode() { return data[randInt(0, data.length)]; }

function pickRandomSize() { return randInt(4000, 20000); }

function walkToAddRandomNode(d) {
  var children = d.children;
  
  if (!children)
    return false;

  var n = children.length;

  if (flipCoin(n)) {
    d.children.push({
      "name": d.name + "." + randInt(0, 200),
      "size": pickRandomSize()
    });
    return true;
  } else {
    var added = false, 
        i = -1;

    while (++i < n && !added) {
      if (walkToAddRandomNode(children[i]))
        added = true;
    }
  }
}

function addRandomNode() { walkToAddRandomNode(nodeData); }

function resizeRandomNode() {
  d = pickRandomNode();
  d.size = pickRandomSize();
}

function addOrResizeRandomNode() {
  (flipCoin() ? resizeRandomNode : addRandomNode)();
  resetLayout();
  draw();
}

d3.json("./readme.json", function(json) {
  data = json;
  nodeData = packages.root(data);
  linkData = packages.imports(data);
  resetLayout();
  draw();

  setInterval(addOrResizeRandomNode, 2000);
});