(function(global) {

  "use strict";

  var fabric = global.fabric || (global.fabric = { });

  if (fabric.Color) {
    fabric.warn('fabric.Color is already defined.');
    return;
  }

  /**
   * Color class
   * The purpose of {@link fabric.Color} is to abstract and encapsulate common color operations;
   * {@link fabric.Color} is a constructor and creates instances of {@link fabric.Color} objects.
   *
   * @class fabric.Color
   * @param {String} color optional in hex or rgb(a) format
   * @return {fabric.Color} thisArg
   * @tutorial {@link http://fabricjs.com/fabric-intro-part-2/#colors}
   */
  function Color(color) {
    if (!color) {
      this.setSource([0, 0, 0, 1]);
    }
    else {
      this._tryParsingColor(color);
    }
  }

  fabric.Color = Color;

  fabric.Color.prototype = /** @lends fabric.Color.prototype */ {

    /**
     * @private
     * @param {String|Array} color Color value to parse
     */
    _tryParsingColor: function(color) {
      var source;

      if (color in Color.colorNameMap) {
        color = Color.colorNameMap[color];
      }

      source = Color.sourceFromHex(color);

      if (!source) {
        source = Color.sourceFromRgb(color);
      }
      if (!source) {
        source = Color.sourceFromHsl(color);
      }
      if (source) {
        this.setSource(source);
      }
    },

    /**
     * Adapted from <a href="https://rawgithub.com/mjijackson/mjijackson.github.com/master/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript.html">https://github.com/mjijackson</a>
     * @private
     * @param {Number} r Red color value
     * @param {Number} g Green color value
     * @param {Number} b Blue color value
     * @return {Array} Hsl color
     */
    _rgbToHsl: function(r, g, b) {
      r /= 255, g /= 255, b /= 255;

      var h, s, l,
          max = fabric.util.array.max([r, g, b]),
          min = fabric.util.array.min([r, g, b]);

      l = (max + min) / 2;

      if (max === min) {
        h = s = 0; // achromatic
      }
      else {
        var d = max - min;
        s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
        switch (max) {
          case r:
            h = (g - b) / d + (g < b ? 6 : 0);
            break;
          case g:
            h = (b - r) / d + 2;
            break;
          case b:
            h = (r - g) / d + 4;
            break;
        }
        h /= 6;
      }

      return [
        Math.round(h * 360),
        Math.round(s * 100),
        Math.round(l * 100)
      ];
    },

    /**
     * Returns source of this color (where source is an array representation; ex: [200, 200, 100, 1])
     * @return {Array}
     */
    getSource: function() {
      return this._source;
    },

    /**
     * Sets source of this color (where source is an array representation; ex: [200, 200, 100, 1])
     * @param {Array} source
     */
    setSource: function(source) {
      this._source = source;
    },

    /**
     * Returns color represenation in RGB format
     * @return {String} ex: rgb(0-255,0-255,0-255)
     */
    toRgb: function() {
      var source = this.getSource();
      return 'rgb(' + source[0] + ',' + source[1] + ',' + source[2] + ')';
    },

    /**
     * Returns color represenation in RGBA format
     * @return {String} ex: rgba(0-255,0-255,0-255,0-1)
     */
    toRgba: function() {
      var source = this.getSource();
      return 'rgba(' + source[0] + ',' + source[1] + ',' + source[2] + ',' + source[3] + ')';
    },

    /**
     * Returns color represenation in HSL format
     * @return {String} ex: hsl(0-360,0%-100%,0%-100%)
     */
    toHsl: function() {
      var source = this.getSource(),
          hsl = this._rgbToHsl(source[0], source[1], source[2]);

      return 'hsl(' + hsl[0] + ',' + hsl[1] + '%,' + hsl[2] + '%)';
    },

    /**
     * Returns color represenation in HSLA format
     * @return {String} ex: hsla(0-360,0%-100%,0%-100%,0-1)
     */
    toHsla: function() {
      var source = this.getSource(),
          hsl = this._rgbToHsl(source[0], source[1], source[2]);

      return 'hsla(' + hsl[0] + ',' + hsl[1] + '%,' + hsl[2] + '%,' + source[3] + ')';
    },

    /**
     * Returns color represenation in HEX format
     * @return {String} ex: FF5555
     */
    toHex: function() {
      var source = this.getSource();

      var r = source[0].toString(16);
      r = (r.length === 1) ? ('0' + r) : r;

      var g = source[1].toString(16);
      g = (g.length === 1) ? ('0' + g) : g;

      var b = source[2].toString(16);
      b = (b.length === 1) ? ('0' + b) : b;

      return r.toUpperCase() + g.toUpperCase() + b.toUpperCase();
    },

    /**
     * Gets value of alpha channel for this color
     * @return {Number} 0-1
     */
    getAlpha: function() {
      return this.getSource()[3];
    },

    /**
     * Sets value of alpha channel for this color
     * @param {Number} alpha Alpha value 0-1
     * @return {fabric.Color} thisArg
     */
    setAlpha: function(alpha) {
      var source = this.getSource();
      source[3] = alpha;
      this.setSource(source);
      return this;
    },

    /**
     * Transforms color to its grayscale representation
     * @return {fabric.Color} thisArg
     */
    toGrayscale: function() {
      var source = this.getSource(),
          average = parseInt((source[0] * 0.3 + source[1] * 0.59 + source[2] * 0.11).toFixed(0), 10),
          currentAlpha = source[3];
      this.setSource([average, average, average, currentAlpha]);
      return this;
    },

    /**
     * Transforms color to its black and white representation
     * @param {Number} threshold
     * @return {fabric.Color} thisArg
     */
    toBlackWhite: function(threshold) {
      var source = this.getSource(),
          average = (source[0] * 0.3 + source[1] * 0.59 + source[2] * 0.11).toFixed(0),
          currentAlpha = source[3];

      threshold = threshold || 127;

      average = (Number(average) < Number(threshold)) ? 0 : 255;
      this.setSource([average, average, average, currentAlpha]);
      return this;
    },

    /**
     * Overlays color with another color
     * @param {String|fabric.Color} otherColor
     * @return {fabric.Color} thisArg
     */
    overlayWith: function(otherColor) {
      if (!(otherColor instanceof Color)) {
        otherColor = new Color(otherColor);
      }

      var result = [],
          alpha = this.getAlpha(),
          otherAlpha = 0.5,
          source = this.getSource(),
          otherSource = otherColor.getSource();

      for (var i = 0; i < 3; i++) {
        result.push(Math.round((source[i] * (1 - otherAlpha)) + (otherSource[i] * otherAlpha)));
      }

      result[3] = alpha;
      this.setSource(result);
      return this;
    }
  };

  /**
   * Regex matching color in RGB or RGBA formats (ex: rgb(0, 0, 0), rgba(255, 100, 10, 0.5), rgba( 255 , 100 , 10 , 0.5 ), rgb(1,1,1), rgba(100%, 60%, 10%, 0.5))
   * @static
   * @field
   * @memberOf fabric.Color
   */
  fabric.Color.reRGBa = /^rgba?\(\s*(\d{1,3}\%?)\s*,\s*(\d{1,3}\%?)\s*,\s*(\d{1,3}\%?)\s*(?:\s*,\s*(\d+(?:\.\d+)?)\s*)?\)$/;

  /**
   * Regex matching color in HSL or HSLA formats (ex: hsl(200, 80%, 10%), hsla(300, 50%, 80%, 0.5), hsla( 300 , 50% , 80% , 0.5 ))
   * @static
   * @field
   * @memberOf fabric.Color
   */
  fabric.Color.reHSLa = /^hsla?\(\s*(\d{1,3})\s*,\s*(\d{1,3}\%)\s*,\s*(\d{1,3}\%)\s*(?:\s*,\s*(\d+(?:\.\d+)?)\s*)?\)$/;

  /**
   * Regex matching color in HEX format (ex: #FF5555, 010155, aff)
   * @static
   * @field
   * @memberOf fabric.Color
   */
  fabric.Color.reHex = /^#?([0-9a-f]{6}|[0-9a-f]{3})$/i;

  /**
   * Map of the 17 basic color names with HEX code
   * @static
   * @field
   * @memberOf fabric.Color
   * @see: http://www.w3.org/TR/CSS2/syndata.html#color-units
   */
  fabric.Color.colorNameMap = {
    'aqua':    '#00FFFF',
    'black':   '#000000',
    'blue':    '#0000FF',
    'fuchsia': '#FF00FF',
    'gray':    '#808080',
    'green':   '#008000',
    'lime':    '#00FF00',
    'maroon':  '#800000',
    'navy':    '#000080',
    'olive':   '#808000',
    'orange':  '#FFA500',
    'purple':  '#800080',
    'red':     '#FF0000',
    'silver':  '#C0C0C0',
    'teal':    '#008080',
    'white':   '#FFFFFF',
    'yellow':  '#FFFF00'
  };

  /**
   * @private
   * @param {Number} p
   * @param {Number} q
   * @param {Number} t
   * @return {Number}
   */
  function hue2rgb(p, q, t){
    if (t < 0) t += 1;
    if (t > 1) t -= 1;
    if (t < 1/6) return p + (q - p) * 6 * t;
    if (t < 1/2) return q;
    if (t < 2/3) return p + (q - p) * (2/3 - t) * 6;
    return p;
  }

  /**
   * Returns new color object, when given a color in RGB format
   * @memberOf fabric.Color
   * @param {String} color Color value ex: rgb(0-255,0-255,0-255)
   * @return {fabric.Color}
   */
  fabric.Color.fromRgb = function(color) {
    return Color.fromSource(Color.sourceFromRgb(color));
  };

  /**
   * Returns array represenatation (ex: [100, 100, 200, 1]) of a color that's in RGB or RGBA format
   * @memberOf fabric.Color
   * @param {String} color Color value ex: rgb(0-255,0-255,0-255), rgb(0%-100%,0%-100%,0%-100%)
   * @return {Array} source
   */
  fabric.Color.sourceFromRgb = function(color) {
    var match = color.match(Color.reRGBa);
    if (match) {
      var r = parseInt(match[1], 10) / (/%$/.test(match[1]) ? 100 : 1) * (/%$/.test(match[1]) ? 255 : 1),
          g = parseInt(match[2], 10) / (/%$/.test(match[2]) ? 100 : 1) * (/%$/.test(match[2]) ? 255 : 1),
          b = parseInt(match[3], 10) / (/%$/.test(match[3]) ? 100 : 1) * (/%$/.test(match[3]) ? 255 : 1);

      return [
        parseInt(r, 10),
        parseInt(g, 10),
        parseInt(b, 10),
        match[4] ? parseFloat(match[4]) : 1
      ];
    }
  };

  /**
   * Returns new color object, when given a color in RGBA format
   * @static
   * @function
   * @memberOf fabric.Color
   * @param {String} color
   * @return {fabric.Color}
   */
  fabric.Color.fromRgba = Color.fromRgb;

  /**
   * Returns new color object, when given a color in HSL format
   * @param {String} color Color value ex: hsl(0-260,0%-100%,0%-100%)
   * @memberOf fabric.Color
   * @return {fabric.Color}
   */
  fabric.Color.fromHsl = function(color) {
    return Color.fromSource(Color.sourceFromHsl(color));
  };

  /**
   * Returns array represenatation (ex: [100, 100, 200, 1]) of a color that's in HSL or HSLA format.
   * Adapted from <a href="https://rawgithub.com/mjijackson/mjijackson.github.com/master/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript.html">https://github.com/mjijackson</a>
   * @memberOf fabric.Color
   * @param {String} color Color value ex: hsl(0-360,0%-100%,0%-100%) or hsla(0-360,0%-100%,0%-100%, 0-1)
   * @return {Array} source
   * @see http://http://www.w3.org/TR/css3-color/#hsl-color
   */
  fabric.Color.sourceFromHsl = function(color) {
    var match = color.match(Color.reHSLa);
    if (!match) return;

    var h = (((parseFloat(match[1]) % 360) + 360) % 360) / 360,
        s = parseFloat(match[2]) / (/%$/.test(match[2]) ? 100 : 1),
        l = parseFloat(match[3]) / (/%$/.test(match[3]) ? 100 : 1),
        r, g, b;

    if (s === 0) {
      r = g = b = l;
    }
    else {
      var q = l <= 0.5 ? l * (s + 1) : l + s - l * s;
      var p = l * 2 - q;

      r = hue2rgb(p, q, h + 1/3);
      g = hue2rgb(p, q, h);
      b = hue2rgb(p, q, h - 1/3);
    }

    return [
      Math.round(r * 255),
      Math.round(g * 255),
      Math.round(b * 255),
      match[4] ? parseFloat(match[4]) : 1
    ];
  };

  /**
   * Returns new color object, when given a color in HSLA format
   * @static
   * @function
   * @memberOf fabric.Color
   * @param {String} color
   * @return {fabric.Color}
   */
  fabric.Color.fromHsla = Color.fromHsl;

  /**
   * Returns new color object, when given a color in HEX format
   * @static
   * @memberOf fabric.Color
   * @param {String} color Color value ex: FF5555
   * @return {fabric.Color}
   */
  fabric.Color.fromHex = function(color) {
    return Color.fromSource(Color.sourceFromHex(color));
  };

  /**
   * Returns array represenatation (ex: [100, 100, 200, 1]) of a color that's in HEX format
   * @static
   * @memberOf fabric.Color
   * @param {String} color ex: FF5555
   * @return {Array} source
   */
  fabric.Color.sourceFromHex = function(color) {
    if (color.match(Color.reHex)) {
      var value = color.slice(color.indexOf('#') + 1),
          isShortNotation = (value.length === 3),
          r = isShortNotation ? (value.charAt(0) + value.charAt(0)) : value.substring(0, 2),
          g = isShortNotation ? (value.charAt(1) + value.charAt(1)) : value.substring(2, 4),
          b = isShortNotation ? (value.charAt(2) + value.charAt(2)) : value.substring(4, 6);

      return [
        parseInt(r, 16),
        parseInt(g, 16),
        parseInt(b, 16),
        1
      ];
    }
  };

  /**
   * Returns new color object, when given color in array representation (ex: [200, 100, 100, 0.5])
   * @static
   * @memberOf fabric.Color
   * @param {Array} source
   * @return {fabric.Color}
   */
  fabric.Color.fromSource = function(source) {
    var oColor = new Color();
    oColor.setSource(source);
    return oColor;
  };

})(typeof exports !== 'undefined' ? exports : this);