/**
 * Represents an RGB color and provides helper functions get
 * color components in HSL color space.
 */
Ext.define('Ext.draw.Color', {

    /* Begin Definitions */

    /* End Definitions */

    colorToHexRe: /(.*?)rgb\((\d+),\s*(\d+),\s*(\d+)\)/,
    rgbRe: /\s*rgb\s*\(\s*([0-9]+)\s*,\s*([0-9]+)\s*,\s*([0-9]+)\s*\)\s*/,
    hexRe: /\s*#([0-9a-fA-F][0-9a-fA-F]?)([0-9a-fA-F][0-9a-fA-F]?)([0-9a-fA-F][0-9a-fA-F]?)\s*/,

    /**
     * @cfg {Number} lightnessFactor
     *
     * The default factor to compute the lighter or darker color. Defaults to 0.2.
     */
    lightnessFactor: 0.2,

    /**
     * Creates new Color.
     * @param {Number} red Red component (0..255)
     * @param {Number} green Green component (0..255)
     * @param {Number} blue Blue component (0..255)
     */
    constructor : function(red, green, blue) {
        var me = this,
            clamp = Ext.Number.constrain;
        me.r = clamp(red, 0, 255);
        me.g = clamp(green, 0, 255);
        me.b = clamp(blue, 0, 255);
    },

    /**
     * Get the red component of the color, in the range 0..255.
     * @return {Number}
     */
    getRed: function() {
        return this.r;
    },

    /**
     * Get the green component of the color, in the range 0..255.
     * @return {Number}
     */
    getGreen: function() {
        return this.g;
    },

    /**
     * Get the blue component of the color, in the range 0..255.
     * @return {Number}
     */
    getBlue: function() {
        return this.b;
    },

    /**
     * Get the RGB values.
     * @return {Number[]}
     */
    getRGB: function() {
        var me = this;
        return [me.r, me.g, me.b];
    },

    /**
     * Get the equivalent HSL components of the color.
     * @return {Number[]}
     */
    getHSL: function() {
        var me = this,
            r = me.r / 255,
            g = me.g / 255,
            b = me.b / 255,
            max = Math.max(r, g, b),
            min = Math.min(r, g, b),
            delta = max - min,
            h,
            s = 0,
            l = 0.5 * (max + min);

        // min==max means achromatic (hue is undefined)
        if (min != max) {
            s = (l < 0.5) ? delta / (max + min) : delta / (2 - max - min);
            if (r == max) {
                h = 60 * (g - b) / delta;
            } else if (g == max) {
                h = 120 + 60 * (b - r) / delta;
            } else {
                h = 240 + 60 * (r - g) / delta;
            }
            if (h < 0) {
                h += 360;
            }
            if (h >= 360) {
                h -= 360;
            }
        }
        return [h, s, l];
    },

    /**
     * Return a new color that is lighter than this color.
     * @param {Number} factor Lighter factor (0..1), default to 0.2
     * @return Ext.draw.Color
     */
    getLighter: function(factor) {
        var hsl = this.getHSL();
        factor = factor || this.lightnessFactor;
        hsl[2] = Ext.Number.constrain(hsl[2] + factor, 0, 1);
        return this.fromHSL(hsl[0], hsl[1], hsl[2]);
    },

    /**
     * Return a new color that is darker than this color.
     * @param {Number} factor Darker factor (0..1), default to 0.2
     * @return Ext.draw.Color
     */
    getDarker: function(factor) {
        factor = factor || this.lightnessFactor;
        return this.getLighter(-factor);
    },

    /**
     * Return the color in the hex format, i.e. '#rrggbb'.
     * @return {String}
     */
    toString: function() {
        var me = this,
            round = Math.round,
            r = round(me.r).toString(16),
            g = round(me.g).toString(16),
            b = round(me.b).toString(16);
        r = (r.length == 1) ? '0' + r : r;
        g = (g.length == 1) ? '0' + g : g;
        b = (b.length == 1) ? '0' + b : b;
        return ['#', r, g, b].join('');
    },

    /**
     * Convert a color to hexadecimal format.
     *
     * **Note:** This method is both static and instance.
     *
     * @param {String/String[]} color The color value (i.e 'rgb(255, 255, 255)', 'color: #ffffff').
     * Can also be an Array, in this case the function handles the first member.
     * @returns {String} The color in hexadecimal format.
     * @static
     */
    toHex: function(color) {
        if (Ext.isArray(color)) {
            color = color[0];
        }
        if (!Ext.isString(color)) {
            return '';
        }
        if (color.substr(0, 1) === '#') {
            return color;
        }
        var digits = this.colorToHexRe.exec(color),
            red,
            green,
            blue,
            rgb;

        if (Ext.isArray(digits)) {
            red = parseInt(digits[2], 10);
            green = parseInt(digits[3], 10);
            blue = parseInt(digits[4], 10);
            rgb = blue | (green << 8) | (red << 16);
            return digits[1] + '#' + ("000000" + rgb.toString(16)).slice(-6);
        }
        else {
            return color;
        }
    },

    /**
     * Parse the string and create a new color.
     *
     * Supported formats: '#rrggbb', '#rgb', and 'rgb(r,g,b)'.
     *
     * If the string is not recognized, an undefined will be returned instead.
     *
     * **Note:** This method is both static and instance.
     *
     * @param {String} str Color in string.
     * @returns Ext.draw.Color
     * @static
     */
    fromString: function(str) {
        var values, r, g, b,
            parse = parseInt;

        if ((str.length == 4 || str.length == 7) && str.substr(0, 1) === '#') {
            values = str.match(this.hexRe);
            if (values) {
                r = parse(values[1], 16) >> 0;
                g = parse(values[2], 16) >> 0;
                b = parse(values[3], 16) >> 0;
                if (str.length == 4) {
                    r += (r * 16);
                    g += (g * 16);
                    b += (b * 16);
                }
            }
        }
        else {
            values = str.match(this.rgbRe);
            if (values) {
                r = values[1];
                g = values[2];
                b = values[3];
            }
        }

        return (typeof r == 'undefined') ? undefined : new Ext.draw.Color(r, g, b);
    },

    /**
     * Returns the gray value (0 to 255) of the color.
     *
     * The gray value is calculated using the formula r*0.3 + g*0.59 + b*0.11.
     *
     * @returns {Number}
     */
    getGrayscale: function() {
        // http://en.wikipedia.org/wiki/Grayscale#Converting_color_to_grayscale
        return this.r * 0.3 + this.g * 0.59 + this.b * 0.11;
    },

    /**
     * Create a new color based on the specified HSL values.
     *
     * **Note:** This method is both static and instance.
     *
     * @param {Number} h Hue component (0..359)
     * @param {Number} s Saturation component (0..1)
     * @param {Number} l Lightness component (0..1)
     * @returns Ext.draw.Color
     * @static
     */
    fromHSL: function(h, s, l) {
        var C, X, m, i, rgb = [],
            abs = Math.abs,
            floor = Math.floor;

        if (s == 0 || h == null) {
            // achromatic
            rgb = [l, l, l];
        }
        else {
            // http://en.wikipedia.org/wiki/HSL_and_HSV#From_HSL
            // C is the chroma
            // X is the second largest component
            // m is the lightness adjustment
            h /= 60;
            C = s * (1 - abs(2 * l - 1));
            X = C * (1 - abs(h - 2 * floor(h / 2) - 1));
            m = l - C / 2;
            switch (floor(h)) {
                case 0:
                    rgb = [C, X, 0];
                    break;
                case 1:
                    rgb = [X, C, 0];
                    break;
                case 2:
                    rgb = [0, C, X];
                    break;
                case 3:
                    rgb = [0, X, C];
                    break;
                case 4:
                    rgb = [X, 0, C];
                    break;
                case 5:
                    rgb = [C, 0, X];
                    break;
            }
            rgb = [rgb[0] + m, rgb[1] + m, rgb[2] + m];
        }
        return new Ext.draw.Color(rgb[0] * 255, rgb[1] * 255, rgb[2] * 255);
    }
}, function() {
    var prototype = this.prototype;

    //These functions are both static and instance. TODO: find a more elegant way of copying them
    this.addStatics({
        fromHSL: function() {
            return prototype.fromHSL.apply(prototype, arguments);
        },
        fromString: function() {
            return prototype.fromString.apply(prototype, arguments);
        },
        toHex: function() {
            return prototype.toHex.apply(prototype, arguments);
        }
    });
});