/* global d3 */

// get the data
d3.tsv('force.tsv', function (error, links) {
  var nodes = {};

  // Compute the distinct nodes from the links.
  links.forEach(function (link) {
    link.source = nodes[link.source] ||
      (nodes[link.source] = {name: link.source});
    link.target = nodes[link.target] ||
      (nodes[link.target] = {name: link.target});
    link.value = +link.value;
  });

  var width = 960;
  var height = 500;

  var force = d3.layout.force()
      .nodes(d3.values(nodes))
      .links(links)
      .size([width, height])
      .linkDistance(60)
      .charge(-300)
      .on('tick', tick)
      .start();

  // Set the range
  var v = d3.scale.linear().range([0, 100]);

  // Scale the range of the data
  v.domain([0, d3.max(links, function (d) { return d.value; })]);

  // asign a type per value to encode opacity
  links.forEach(function (link) {
    if (v(link.value) <= 25) {
      link.type = 'twofive';
    } else if (v(link.value) <= 50 && v(link.value) > 25) {
      link.type = 'fivezero';
    } else if (v(link.value) <= 75 && v(link.value) > 50) {
      link.type = 'sevenfive';
    } else if (v(link.value) <= 100 && v(link.value) > 75) {
      link.type = 'onezerozero';
    }
  });

  var svg = d3.select('body').append('svg')
      .attr('width', width)
      .attr('height', height);

  // build the arrow.
  svg.append('svg:defs').selectAll('marker')
      .data(['end'])      // Different link/path types can be defined here
    .enter().append('svg:marker')    // This section adds in the arrows
      .attr('id', String)
      .attr('viewBox', '0 -5 10 10')
      .attr('refX', 15)
      .attr('refY', -1.5)
      .attr('markerWidth', 6)
      .attr('markerHeight', 6)
      .attr('orient', 'auto')
    .append('svg:path')
      .attr('d', 'M0,-5L10,0L0,5');

  // add the links and the arrows
  var path = svg.append('svg:g').selectAll('path')
      .data(force.links())
    .enter().append('svg:path')
      .attr('class', function (d) { return 'link ' + d.type; })
      .attr('marker-end', 'url(#end)');

  // define the nodes
  var node = svg.selectAll('.node')
      .data(force.nodes())
    .enter().append('g')
      .attr('class', 'node')
      .on('click', click)
      .call(force.drag);

  // add the nodes
  node.append('circle')
      .attr('r', 5);

  // add the text
  node.append('text')
      .attr('x', 12)
      .attr('dy', '.35em')
      .on('click', nameClick)
      .text(function (d) { return d.name; });

  // add the curvy lines
  function tick () {
    path.attr('d', function (d) {
      var dx = d.target.x - d.source.x;
      var dy = d.target.y - d.source.y;
      var dr = Math.sqrt(dx * dx + dy * dy);

      return 'M' +
        d.source.x + ',' +
        d.source.y + 'A' +
        dr + ',' + dr + ' 0 0,1 ' +
        d.target.x + ',' +
        d.target.y;
    });

    node
      .attr('transform', function (d) {
        return 'translate(' + d.x + ',' + d.y + ')';
      });
  }

  // action to take on mouse click
  function click (d) {
    if (d.selected) {
      d.selected = false;
      d3.select(this).select('circle').transition()
          .duration(750)
          .attr('r', 6)
          .style('fill', '#ccc');
      d3.select(this).select('text').transition()
          .duration(750)
          .attr('x', 12)
          .style('stroke', 'none')
          .style('fill', 'black')
          .style('stroke', 'none')
          .style('font', '10px sans-serif');
    } else {
      d.selected = true;
      d3.select(this).select('text').transition()
          .duration(750)
          .attr('x', 22)
          .style('fill', 'steelblue')
          .style('stroke', 'lightsteelblue')
          .style('stroke-width', '.5px')
          .style('font', '20px sans-serif');

      d3.select(this).select('circle').transition()
          .duration(750)
          .attr('r', 16)
          .style('fill', 'lightsteelblue');
    }
  }

  // action to take on mouse double click
  function nameClick (d) {
    var win = window.open('https://github.com/Hypercubed/' + d.name, '_blank');
    win.focus();
  }
});