(function () {
    'use strict';
    /**
     * Emboss Filter.
     * Pixastic Lib - Emboss filter - v0.1.0
     * Copyright (c) 2008 Jacob Seidelin, jseidelin@nihilogic.dk, http://blog.nihilogic.dk/
     * License: [http://www.pixastic.com/lib/license.txt]
     * @function
     * @memberof Konva.Filters
     * @param {Object} imageData
     * @example
     * node.cache();
     * node.filters([Konva.Filters.Emboss]);
     * node.embossStrength(0.8);
     * node.embossWhiteLevel(0.3);
     * node.embossDirection('right');
     * node.embossBlend(true);
     */
    Konva.Filters.Emboss = function (imageData) {

        // pixastic strength is between 0 and 10.  I want it between 0 and 1
        // pixastic greyLevel is between 0 and 255.  I want it between 0 and 1.  Also,
        // a max value of greyLevel yields a white emboss, and the min value yields a black
        // emboss.  Therefore, I changed greyLevel to whiteLevel
        var strength = this.embossStrength() * 10,
            greyLevel = this.embossWhiteLevel() * 255,
            direction = this.embossDirection(),
            blend = this.embossBlend(),
            dirY = 0,
            dirX = 0,
            data = imageData.data,
            w = imageData.width,
            h = imageData.height,
            w4 = w * 4,
            y = h;

        switch (direction) {
            case 'top-left':
                dirY = -1;
                dirX = -1;
                break;
            case 'top':
                dirY = -1;
                dirX = 0;
                break;
            case 'top-right':
                dirY = -1;
                dirX = 1;
                break;
            case 'right':
                dirY = 0;
                dirX = 1;
                break;
            case 'bottom-right':
                dirY = 1;
                dirX = 1;
                break;
            case 'bottom':
                dirY = 1;
                dirX = 0;
                break;
            case 'bottom-left':
                dirY = 1;
                dirX = -1;
                break;
            case 'left':
                dirY = 0;
                dirX = -1;
                break;
        }

        do {
            var offsetY = (y - 1) * w4;

            var otherY = dirY;
            if (y + otherY < 1){
                otherY = 0;
            }
            if (y + otherY > h) {
                otherY = 0;
            }

            var offsetYOther = (y - 1 + otherY) * w * 4;

            var x = w;
            do {
                var offset = offsetY + (x - 1) * 4;

                var otherX = dirX;
                if (x + otherX < 1){
                    otherX = 0;
                }
                if (x + otherX > w) {
                    otherX = 0;
                }

                var offsetOther = offsetYOther + (x - 1 + otherX) * 4;

                var dR = data[offset] - data[offsetOther];
                var dG = data[offset + 1] - data[offsetOther + 1];
                var dB = data[offset + 2] - data[offsetOther + 2];

                var dif = dR;
                var absDif = dif > 0 ? dif : -dif;

                var absG = dG > 0 ? dG : -dG;
                var absB = dB > 0 ? dB : -dB;

                if (absG > absDif) {
                    dif = dG;
                }
                if (absB > absDif) {
                    dif = dB;
                }

                dif *= strength;

                if (blend) {
                    var r = data[offset] + dif;
                    var g = data[offset + 1] + dif;
                    var b = data[offset + 2] + dif;

                    data[offset] = (r > 255) ? 255 : (r < 0 ? 0 : r);
                    data[offset + 1] = (g > 255) ? 255 : (g < 0 ? 0 : g);
                    data[offset + 2] = (b > 255) ? 255 : (b < 0 ? 0 : b);
                } else {
                    var grey = greyLevel - dif;
                    if (grey < 0) {
                        grey = 0;
                    } else if (grey > 255) {
                        grey = 255;
                    }

                    data[offset] = data[offset + 1] = data[offset + 2] = grey;
                }

            } while (--x);
        } while (--y);
    };

    Konva.Factory.addGetterSetter(Konva.Node, 'embossStrength', 0.5, null, Konva.Factory.afterSetFilter);
    /**
    * get/set emboss strength. Use with {@link Konva.Filters.Emboss} filter.
    * @name embossStrength
    * @method
    * @memberof Konva.Node.prototype
    * @param {Number} level between 0 and 1.  Default is 0.5
    * @returns {Number}
    */

    Konva.Factory.addGetterSetter(Konva.Node, 'embossWhiteLevel', 0.5, null, Konva.Factory.afterSetFilter);
    /**
    * get/set emboss white level. Use with {@link Konva.Filters.Emboss} filter.
    * @name embossWhiteLevel
    * @method
    * @memberof Konva.Node.prototype
    * @param {Number} embossWhiteLevel between 0 and 1.  Default is 0.5
    * @returns {Number}
    */

    Konva.Factory.addGetterSetter(Konva.Node, 'embossDirection', 'top-left', null, Konva.Factory.afterSetFilter);
    /**
    * get/set emboss direction. Use with {@link Konva.Filters.Emboss} filter.
    * @name embossDirection
    * @method
    * @memberof Konva.Node.prototype
    * @param {String} embossDirection can be top-left, top, top-right, right, bottom-right, bottom, bottom-left or left
    *   The default is top-left
    * @returns {String}
    */

    Konva.Factory.addGetterSetter(Konva.Node, 'embossBlend', false, null, Konva.Factory.afterSetFilter);
    /**
    * get/set emboss blend. Use with {@link Konva.Filters.Emboss} filter.
    * @name embossBlend
    * @method
    * @memberof Konva.Node.prototype
    * @param {Boolean} embossBlend
    * @returns {Boolean}
    */
})();