/*
 * @copyright Copyright (c) 2016 Julius Härtl <jus@bitgrid.net>
 *
 * @author Julius Härtl <jus@bitgrid.net>
 *
 * @license GNU AGPL version 3 or any later version
 *  
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *  
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *  
 */

app.filter('iconWhiteFilter', function() {
	return function (hex) {
		// RGB2HLS by Garry Tan
		// http://axonflux.com/handy-rgb-to-hsl-and-rgb-to-hsv-color-model-c
		var result = /^([A-Fa-f\d]{2})([A-Fa-f\d]{2})([A-Fa-f\d]{2})$/i.exec(hex);
		var color = result ? {
			r: parseInt(result[1], 16),
			g: parseInt(result[2], 16),
			b: parseInt(result[3], 16)
		} : null;
		if(result !== null) {
			var r = color.r/255;
			var g = color.g/255;
			var b = color.b/255;
			var max = Math.max(r, g, b), min = Math.min(r, g, b);
			var h, s, 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;
			}
			// TODO: Maybe just darken/lighten the color
			if(l<0.5) {
				return "-white";
			} else {
				return "";
			}
			//var rgba = "rgba(" + color.r + "," + color.g + "," + color.b + ",0.7)";
			//return rgba;
		} else {
			return "";
		}

	}
});