/*eslint-disable max-depth */
(function () {
    'use strict';
    /**
     * Pixelate Filter. Averages groups of pixels and redraws
     *  them as larger pixels
     * @function
     * @name Pixelate
     * @memberof Konva.Filters
     * @param {Object} imageData
     * @author ippo615
     * @example
     * node.cache();
     * node.filters([Konva.Filters.Pixelate]);
     * node.pixelSize(10);
     */

    Konva.Filters.Pixelate = function (imageData) {

        var pixelSize = Math.ceil(this.pixelSize()),
            width = imageData.width,
            height = imageData.height,
            x, y, i,
            //pixelsPerBin = pixelSize * pixelSize,
            red, green, blue, alpha,
            nBinsX = Math.ceil(width / pixelSize),
            nBinsY = Math.ceil(height / pixelSize),
            xBinStart, xBinEnd, yBinStart, yBinEnd,
            xBin, yBin, pixelsInBin;
        imageData = imageData.data;

        if (pixelSize <= 0) {
            Konva.Util.error('pixelSize value can not be <= 0');
            return;
        }

        for (xBin = 0; xBin < nBinsX; xBin += 1) {
            for (yBin = 0; yBin < nBinsY; yBin += 1) {

                // Initialize the color accumlators to 0
                red = 0;
                green = 0;
                blue = 0;
                alpha = 0;

                // Determine which pixels are included in this bin
                xBinStart = xBin * pixelSize;
                xBinEnd = xBinStart + pixelSize;
                yBinStart = yBin * pixelSize;
                yBinEnd = yBinStart + pixelSize;

                // Add all of the pixels to this bin!
                pixelsInBin = 0;
                for (x = xBinStart; x < xBinEnd; x += 1) {
                    if( x >= width ){ continue; }
                    for (y = yBinStart; y < yBinEnd; y += 1) {
                        if( y >= height ){ continue; }
                        i = (width * y + x) * 4;
                        red += imageData[i + 0];
                        green += imageData[i + 1];
                        blue += imageData[i + 2];
                        alpha += imageData[i + 3];
                        pixelsInBin += 1;
                    }
                }

                // Make sure the channels are between 0-255
                red = red / pixelsInBin;
                green = green / pixelsInBin;
                blue = blue / pixelsInBin;

                // Draw this bin
                for (x = xBinStart; x < xBinEnd; x += 1) {
                    if( x >= width ){ continue; }
                    for (y = yBinStart; y < yBinEnd; y += 1) {
                        if( y >= height ){ continue; }
                        i = (width * y + x) * 4;
                        imageData[i + 0] = red;
                        imageData[i + 1] = green;
                        imageData[i + 2] = blue;
                        imageData[i + 3] = alpha;
                    }
                }
            }
        }

    };

    Konva.Factory.addGetterSetter(Konva.Node, 'pixelSize', 8, null, Konva.Factory.afterSetFilter);

    /**
    * get/set pixel size. Use with {@link Konva.Filters.Pixelate} filter.
    * @name pixelSize
    * @method
    * @memberof Konva.Node.prototype
    * @param {Integer} pixelSize
    * @returns {Integer}
    */
})();