/**
 * SVG Fixer
 *
 * Fixes references to inline SVG elements when the <base> tag is in use.
 * Firefox won't display SVG icons referenced with
 * `<svg><use xlink:href="#id-of-icon-def"></use></svg>` when the <base> tag is on the page.
 *
 * More info:
 * - http://stackoverflow.com/a/18265336/796152
 * - http://www.w3.org/TR/SVG/linking.html
 *
 * One would think that setting the `xml:base` attribute fixes things,
 * but that is being removed from the platform: https://code.google.com/p/chromium/issues/detail?id=341854
 */

(function(document, window) {
	"use strict";

	/**
	* Initialize the SVG Fixer after the DOM is ready
	*/
	document.addEventListener("DOMContentLoaded", function() {

		/**
		 * Current URL, without the hash
		 */
		var baseUrl = window.location.href
			.replace(window.location.hash, "");

		/**
		*  Find all `use` elements with a namespaced `href` attribute, e.g.
		*  <use xlink:href="#some-id"></use>
		*
		*  See: http://stackoverflow.com/a/23047888/796152
		*/
		[].slice.call(document.querySelectorAll("use[*|href]"))

			/**
			* Filter out all elements whose namespaced `href` attribute doesn't
			* start with `#` (i.e. all non-relative IRI's)
			*
			* Note: we're assuming the `xlink` prefix for the XLink namespace!
			*/
			.filter(function(element) {
				return (element.getAttribute("xlink:href").indexOf("#") === 0);
			})

			/**
			* Prepend `window.location` to the namespaced `href` attribute value,
			* in order to make it an absolute IRI
			*
			* Note: we're assuming the `xlink` prefix for the XLink namespace!
			*/
			.forEach(function(element) {
				element.setAttribute("xlink:href", baseUrl + element.getAttribute("xlink:href"));
			});
            /**
            *  Find all `use` elements with a namespaced `fill` attribute, e.g.
            *  <use xlink:href="#some-id" fill="url(#some-id)"></use>
            *
            *  See: http://stackoverflow.com/a/23047888/796152
            */
            [].slice.call(document.querySelectorAll("use[*|fill]"))

            /**
            * Filter out all elements whose namespaced `fill` attributes doesn't
            * which doesnt have cross referenced values
            *
            * Note: we're assuming the `url(` prefix for the cross referenced fills !
            */
            .filter(function(element) {
                return (element.getAttribute("fill").indexOf("url(") === 0);
            })

            /**
            * Insert `window.location` to the `fill` attribute value,
            * in order to make it an absolute IRI
            *
            */
            .forEach(function(element) {
                var attrVal = element.getAttribute("fill");
                var idx = attrVal.indexOf("url(");
                element.setAttribute("fill",attrVal.slice(0,idx+4)+baseUrl+ attrVal.slice(idx+4));
            });		

	}, false);

}(document, window));