(function() {

  window.main = function() {
    /* "globals"
    */
    var container, dx, dy, height, path_generator, radius, svg, vis, width;
    vis = null;
    width = 960;
    height = 500;
    svg = d3.select('body').append('svg').attr('width', width).attr('height', height);
    /* ZOOM and PAN
    */
    /* create container elements
    */
    container = svg.append('g').attr('transform', 'translate(640, 34)');
    container.call(d3.behavior.zoom().scaleExtent([1, 49]).on('zoom', (function() {
      return vis.attr('transform', "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")");
    })));
    vis = container.append('g');
    /* create a rectangular overlay to catch events
    */
    /* WARNING rect size is huge but not infinite. this is a dirty hack
    */
    vis.append('rect').attr('class', 'overlay').attr('x', -500000).attr('y', -500000).attr('width', 1000000).attr('height', 1000000);
    /* END ZOOM and PAN
    */
    /* custom projection to make hexagons appear regular (y axis is also flipped)
    */
    radius = 1;
    dx = radius * 2 * Math.sin(Math.PI / 3);
    dy = radius * 1.5;
    path_generator = d3.geo.path().projection(d3.geo.transform({
      point: function(x, y, z) {
        /* draw only nodes that are "important" enough
        */        return this.stream.point(x * dx / 2, -(y - (2 - (y & 1)) / 3) * dy / 2);
      }
    }));
    /* load topoJSON data
    */
    return d3.json('regions_48207.topo.json', function(error, data) {
      /* presimplify the topology (compute the effective area (z) of each point)
      */
      /* data.objects contain all the map layers
      */
      /* each layer represents a different level of the tree
      */
      /* the number of layers is equal to the depth of the tree
      */
      var defs, depth, i;
      depth = Object.keys(data.objects).length;
      /* draw the level zero region (the land)
      */
      defs = svg.append('defs');
      defs.selectAll('#land').data(topojson.feature(data, data.objects[0]).features).enter().append('path').attr('id', 'land').attr('d', path_generator);
      /* faux land glow (using filters takes too much resources)
      */
      vis.append('use').attr('class', 'land-glow-outer').attr('xlink:href', '#land');
      vis.append('use').attr('class', 'land-glow-inner').attr('xlink:href', '#land');
      vis.append('use').attr('class', 'land-fill').attr('xlink:href', '#land');
      /* draw the boundaries
      */
      for (i = 1; i < 4; i++) {
        vis.append('path').datum(topojson.mesh(data, data.objects[i], (function(a, b) {
          return a.properties.prefix.slice(0, -1) === b.properties.prefix.slice(0, -1);
        }))).attr('d', path_generator).attr('class', 'boundary').style('stroke-width', "" + (0.7 / (i * i)) + "px");
      }
      /* draw the labels
      */
      return vis.selectAll('.label').data(topojson.feature(data, data.objects[1]).features.concat(topojson.feature(data, data.objects[2]).features, topojson.feature(data, data.objects[3]).features)).enter().append('text').attr('class', 'label').attr('dy', '0.35em').attr('transform', (function(d) {
        var centroid;
        centroid = path_generator.centroid(d);
        return "translate(" + centroid[0] + "," + centroid[1] + ") scale(" + (20 / (Math.pow(d.properties.prefix.length, 1.7))) + ")";
      })).text(function(d) {
        return d.properties.prefix;
      });
    });
  };

}).call(this);