// ==========================================================================
// Project:   SproutCore - JavaScript Application Framework
// Copyright: ©2006-2011 Strobe Inc. and contributors.
//            ©2008-2011 Apple Inc. All rights reserved.
// License:   Licensed under MIT license (see license.js)
// ==========================================================================

SC.mixin ( /** @scope SC */ {

  /** Returns hex color from hsv value */
  convertHsvToHex: function (h, s, v) {
    var r = 0, g = 0, b = 0;

    if (v > 0) {
      var i = (h == 1) ? 0 : Math.floor(h * 6),
          f = (h == 1) ? 0 : (h * 6) - i,
          p = v * (1 - s),
          q = v * (1 - (s * f)),
          t = v * (1 - (s * (1 - f))),
          rgb = [[v,t,p],[q,v,p],[p,v,t],[p,q,v],[t,p,v],[v,p,q]];
      r = Math.round(255 * rgb[i][0]);
      g = Math.round(255 * rgb[i][1]);
      b = Math.round(255 * rgb[i][2]);
    }
    return this.parseColor('rgb(' + r + ',' + g + ',' + b + ')');
  },

  /** Returns hsv color from hex value */
  convertHexToHsv: function (hex) {
    var rgb = this.expandColor(hex),
        max = Math.max(Math.max(rgb[0], rgb[1]), rgb[2]),
        min = Math.min(Math.min(rgb[0], rgb[1]), rgb[2]),
        s = (max === 0) ? 0 : (1 - min/max),
        v = max/255,
        h = (max == min) ? 0 : ((max == rgb[0]) ? ((rgb[1]-rgb[2])/(max-min)/6) : ((max == rgb[1]) ? ((rgb[2]-rgb[0])/(max-min)/6+1/3) : ((rgb[0]-rgb[1])/(max-min)/6+2/3)));
    h = (h < 0) ? (h + 1) : ((h > 1)  ? (h - 1) : h);
    return [h, s, v];
  },

  /** regular expression for parsing color: rgb, hex */
  PARSE_COLOR_RGBRE: /^rgb\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)$/i,
  PARSE_COLOR_HEXRE: /^\#([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$/,

  // return an array of r,g,b colour
  expandColor: function(color) {
    var hexColor, red, green, blue;
    hexColor = this.parseColor(color);
    if (hexColor) {
      red = parseInt(hexColor.slice(1, 3), 16);
      green = parseInt(hexColor.slice(3, 5), 16);
      blue = parseInt(hexColor.slice(5, 7), 16);
      return [red,green,blue];
    }
  },

  // parse rgb color or 3-digit hex color to return a properly formatted 6-digit hex colour spec, or false
  parseColor: function(string) {
    var i=0, color = '#', match, part;
    if(match = this.PARSE_COLOR_RGBRE.exec(string)) {
      for (i=1; i<=3; i++) {
        part = Math.max(0, Math.min(255, parseInt(match[i],0)));
        color += this.toColorPart(part);
      }
      return color;
    }
    if (match = this.PARSE_COLOR_HEXRE.exec(string)) {
      if(match[1].length == 3) {
        for (i=0; i<3; i++) {
          color += match[1].charAt(i) + match[1].charAt(i);
        }
        return color;
      }
      return '#' + match[1];
    }
    return false;
  },

  // convert one r,g,b number to a 2 digit hex string
  toColorPart: function(number) {
    if (number > 255) number = 255;
    var digits = number.toString(16);
    if (number < 16) return '0' + digits;
    return digits;
  }


});