// Generated by CoffeeScript 1.10.0
(function() {
  var GOSPER_ANGLE;

  GOSPER_ANGLE = Math.acos(5 * Math.sqrt(7) / 14) / Math.PI * 180;

  window.hept_tree_utils = {

    /* Rotates a point around the origin
     */
    rotate_point: function(point, theta) {
      var new_point;
      theta = theta * Math.PI / 180;
      return new_point = {
        x: point.x * Math.cos(theta) - point.y * Math.sin(theta),
        y: point.x * Math.sin(theta) + point.y * Math.cos(theta)
      };
    },

    /* Returns the coordinates of a hexagon
     */
    get_hept_coords: function(scale, index) {
      var a, coords, r;
      a = scale / Math.sqrt(7);
      r = a / Math.sin(Math.PI / 3);
      coords = [
        {
          x: -a,
          y: r + r / 2
        }, {
          x: a,
          y: r + r / 2
        }, {
          x: 0,
          y: 0
        }, {
          x: -2 * a,
          y: 0
        }, {
          x: -a,
          y: -r - r / 2
        }, {
          x: a,
          y: -r - r / 2
        }, {
          x: 2 * a,
          y: 0
        }
      ];
      return coords[index];
    },

    /* Returns the rotation, translation and scale of a certain hexagon described as a base 7 number
     */
    get_hex_data: function(indexes) {
      var hept_coords, i, index, j, len, rotation, scale, scale_i, translation;
      rotation = GOSPER_ANGLE * indexes.length;
      translation = {
        x: 0,
        y: 0
      };
      scale = 1 / Math.pow(Math.sqrt(7), indexes.length);
      for (i = j = 0, len = indexes.length; j < len; i = ++j) {
        index = indexes[i];
        scale_i = 1 / Math.pow(Math.sqrt(7), i);
        hept_coords = hept_tree_utils.get_hept_coords(scale_i, index);
        hept_coords = hept_tree_utils.rotate_point(hept_coords, GOSPER_ANGLE * (i + 1));
        translation.x += hept_coords.x;
        translation.y += hept_coords.y;
      }
      return {
        rotation: rotation,
        translation: translation,
        scale: scale
      };
    },

    /* Generates a haxagons using SVG path
     */
    hex_generate_svg_path: function(a, theta) {
      var r;
      r = a / Math.sin(Math.PI / 3);
      return "M" + a + " " + (r / 2) + " L0 " + r + " L" + (-a) + " " + (r / 2) + " L" + (-a) + " " + (-r / 2) + " L0 " + (-r) + " L" + a + " " + (-r / 2) + " Z";
    }
  };

}).call(this);