D3 Script loader

'use strict';

angular
	.module('common.d3')
	.provider('common.d3.loader', function() {

		// Default to CDN
		this.scriptUrl = 'http://d3js.org/d3.v3.min.js';

		this.$get = ['$window', '$document', '$q', function($window, $document, $q) {

			var defer = $q.defer(),
				scriptUrl = this.scriptUrl;

			return {

				done: function(){

					var	onScriptLoad = function(){
							return defer.resolve($window.d3);
						};

					if($window.d3){
						onScriptLoad();
					}
					else{
						var scriptTag = $document[0].createElement('script');

						scriptTag.type = 'text/javascript';
						scriptTag.async = true;
						scriptTag.src = scriptUrl;
						scriptTag.onreadystatechange = function () {
							if (this.readyState === 'complete') {
								onScriptLoad();
							}else{
								defer.reject();
							}
						};
						scriptTag.onload = onScriptLoad;
						var s = $document[0].getElementsByTagName('body')[0];
						s.appendChild(scriptTag);
					}

					return defer.promise;
				}
			};
		}];

		this.setScriptUrl = function(url) {
			this.scriptUrl = url;
		};


	});