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

	var isSvg = document.createElementNS && document.createElementNS( 'http://www.w3.org/2000/svg', 'svg' ).createSVGRect;
	var localStorage = 'localStorage' in window && window['localStorage'] !== null ? window.localStorage : false;

	function svgSpriteInjector(source, opts) {
		var file;
		opts = opts || {};

		if (source instanceof Node) {
			file = source.getAttribute('data-svg-sprite');
			opts.revision = source.getAttribute('data-svg-sprite-revision') || opts.revision;
		} else if (typeof source === 'string') {
			file = source;
		}

		if (isSvg) {
			if (file) {
				injector(file, opts);
			} else {
				console.error('svg-sprite-injector: undefined sprite filename!');
			}
		} else {
			console.error('svg-sprite-injector require ie9 or greater!');
		}
	};

	function injector(filepath, opts) {
		var name = 'injectedSVGSprite' + filepath,
			revision = opts.revision,
			request;

		// localStorage cache
		if (revision !== undefined && localStorage && localStorage[name + 'Rev'] == revision) {
			return injectOnLoad(localStorage[name]);
		}

		// Async load
		request = new XMLHttpRequest();
		request.open('GET', filepath, true);
		request.onreadystatechange = function (e) {
			var data;

			if (request.readyState === 4 && request.status >= 200 && request.status < 400) {
				injectOnLoad(data = request.responseText);
				if (revision !== undefined && localStorage) {
					localStorage[name] = data;
					localStorage[name + 'Rev'] = revision;
				}
			}
		};
		request.send();
	}

	function injectOnLoad(data) {
		if (data) {
			if (document.body) {
				injectData(data);
			} else {
				document.addEventListener('DOMContentLoaded', injectData.bind(null, data));
			}
		}
	}

	function injectData(data) {
		var body = document.body;
		body.insertAdjacentHTML('afterbegin', data);
		if (body.firstChild.tagName === 'svg') {
			body.firstChild.style.display = 'none';
		}
	}

	if (typeof exports === 'object') {
		module.exports = svgSpriteInjector;
	} else {
		window.svgSpriteInjector = svgSpriteInjector;
	}

} (window, document));