/*!
 * Color animation jQuery-plugin
 * http://www.bitstorm.org/jquery/color-animation/
 * Copyright 2011 Edwin Martin <edwin@bitstorm.org>
 * Released under the MIT and GPL licenses.
 */

(function($) {
   /**
    * Check whether the browser supports RGBA color mode.
    *
    * Author Mehdi Kabab <http://pioupioum.fr>
    * @return {boolean} True if the browser support RGBA. False otherwise.
    */
   function isRGBACapable() {
      var $script = $('script:first'),
            color = $script.css('color'),
            result = false;
      if (/^rgba/.test(color)) {
         result = true;
      } else {
         try {
            result = ( color != $script.css('color', 'rgba(0, 0, 0, 0.5)').css('color') );
            $script.css('color', color);
         } catch (e) {
         }
      }

      return result;
   }

   $.extend(true, $, {
      support: {
         'rgba': isRGBACapable()
      }
   });

   var properties = ['color', 'backgroundColor', 'borderBottomColor', 'borderLeftColor', 'borderRightColor', 'borderTopColor', 'outlineColor'];
   $.each(properties, function(i, property) {
      $.fx.step[property] = function(fx) {
         if (!fx.init) {
            fx.begin = parseColor($(fx.elem).css(property));
            fx.end = parseColor(fx.end);
            fx.init = true;
         }

         fx.elem.style[property] = calculateColor(fx.begin, fx.end, fx.pos);
      }
   });

   // borderColor doesn't fit in standard fx.step above.
   $.fx.step.borderColor = function(fx) {
      if (!fx.init) {
         fx.end = parseColor(fx.end);
      }
      var borders = properties.slice(2, 6); // All four border properties
      $.each(borders, function(i, property) {
         if (!fx.init) {
            fx[property] = {begin: parseColor($(fx.elem).css(property))};
         }

         fx.elem.style[property] = calculateColor(fx[property].begin, fx.end, fx.pos);
      });
      fx.init = true;
   }

   // Calculate an in-between color. Returns "#aabbcc"-like string.
   function calculateColor(begin, end, pos) {
      var color = 'rgb' + ($.support['rgba'] ? 'a' : '') + '('
            + parseInt((begin[0] + pos * (end[0] - begin[0])), 10) + ','
            + parseInt((begin[1] + pos * (end[1] - begin[1])), 10) + ','
            + parseInt((begin[2] + pos * (end[2] - begin[2])), 10);
      if ($.support['rgba']) {
         color += ',' + (begin && end ? parseFloat(begin[3] + pos * (end[3] - begin[3])) : 1);
      }
      color += ')';
      return color;
   }

   // Parse an CSS-syntax color. Outputs an array [r, g, b]
   function parseColor(color) {
      var match, triplet;

      // Match #aabbcc
      if (match = /#([0-9a-fA-F]{2})([0-9a-fA-F]{2})([0-9a-fA-F]{2})/.exec(color)) {
         triplet = [parseInt(match[1], 16), parseInt(match[2], 16), parseInt(match[3], 16), 1];

         // Match #abc
      } else if (match = /#([0-9a-fA-F])([0-9a-fA-F])([0-9a-fA-F])/.exec(color)) {
         triplet = [parseInt(match[1], 16) * 17, parseInt(match[2], 16) * 17, parseInt(match[3], 16) * 17, 1];

         // Match rgb(n, n, n)
      } else if (match = /rgb\(\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*\)/.exec(color)) {
         triplet = [parseInt(match[1]), parseInt(match[2]), parseInt(match[3]), 1];

      } else if (match = /rgba\(\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([01\.]*)\s*\)/.exec(color)) {
         triplet = [parseInt(match[1], 10), parseInt(match[2], 10), parseInt(match[3], 10),parseFloat(match[4])];

         // No browser returns rgb(n%, n%, n%), so little reason to support this format.
      }
      return triplet;
   }
})(jQuery);