/*
 * Require-CSS RequireJS css! loader plugin
 * 0.1.8
 * Guy Bedford 2014
 * MIT
 */

/*
 *
 * Usage:
 *  require(['css!./mycssFile']);
 *
 * Tested and working in (up to latest versions as of March 2013):
 * Android
 * iOS 6
 * IE 6 - 10
 * Chome 3 - 26
 * Firefox 3.5 - 19
 * Opera 10 - 12
 * 
 * browserling.com used for virtual testing environment
 *
 * Credit to B Cavalier & J Hann for the IE 6 - 9 method,
 * refined with help from Martin Cermak
 * 
 * Sources that helped along the way:
 * - https://developer.mozilla.org/en-US/docs/Browser_detection_using_the_user_agent
 * - http://www.phpied.com/when-is-a-stylesheet-really-loaded/
 * - https://github.com/cujojs/curl/blob/master/src/curl/plugin/css.js
 *
 */

define(function() {
	//>>excludeStart('excludeRequireCss', pragmas.excludeRequireCss)
	if (typeof window == 'undefined')
		return {
			load: function(n, r, load) {
				load()
			}
		};

	var head = document.getElementsByTagName('head')[0];

	var engine = window.navigator.userAgent.match(/Trident\/([^ ;]*)|AppleWebKit\/([^ ;]*)|Opera\/([^ ;]*)|rv\:([^ ;]*)(.*?)Gecko\/([^ ;]*)|MSIE\s([^ ;]*)|AndroidWebKit\/([^ ;]*)/) || 0;

	// use <style> @import load method (IE < 9, Firefox < 18)
	var useImportLoad = false;

	// set to false for explicit <link> load checking when onload doesn't work perfectly (webkit)
	var useOnload = true;

	// trident / msie
	if (engine[1] || engine[7])
		useImportLoad = parseInt(engine[1]) < 6 || parseInt(engine[7]) <= 9;
	// webkit
	else if (engine[2] || engine[8])
		useOnload = false;
	// gecko
	else if (engine[4])
		useImportLoad = parseInt(engine[4]) < 18;

	//>>excludeEnd('excludeRequireCss')
	//main api object
	var cssAPI = {};

	//>>excludeStart('excludeRequireCss', pragmas.excludeRequireCss)
	cssAPI.pluginBuilder = './css-builder';

	// <style> @import load method
	var curStyle, curSheet;
	var createStyle = function() {
		curStyle = document.createElement('style');
		head.appendChild(curStyle);
		curSheet = curStyle.styleSheet || curStyle.sheet;
	}
	var ieCnt = 0;
	var ieLoads = [];
	var ieCurCallback;

	var createIeLoad = function(url) {
		curSheet.addImport(url);
		curStyle.onload = function() {
			processIeLoad()
		};

		ieCnt++;
		if (ieCnt == 31) {
			createStyle();
			ieCnt = 0;
		}
	}
	var processIeLoad = function() {
		ieCurCallback();

		var nextLoad = ieLoads.shift();

		if (!nextLoad) {
			ieCurCallback = null;
			return;
		}

		ieCurCallback = nextLoad[1];
		createIeLoad(nextLoad[0]);
	}
	var importLoad = function(url, callback) {
		if (!curSheet || !curSheet.addImport)
			createStyle();

		if (curSheet && curSheet.addImport) {
			// old IE
			if (ieCurCallback) {
				ieLoads.push([url, callback]);
			} else {
				createIeLoad(url);
				ieCurCallback = callback;
			}
		} else {
			// old Firefox
			curStyle.textContent = '@import "' + url + '";';

			var loadInterval = setInterval(function() {
				try {
					curStyle.sheet.cssRules;
					clearInterval(loadInterval);
					callback();
				} catch (e) {}
			}, 10);
		}
	}

	// <link> load method
	var linkLoad = function(url, callback) {
		var link = document.createElement('link');
		link.type = 'text/css';
		link.rel = 'stylesheet';
		if (useOnload) {
			link.onload = function() {
				link.onload = function() {};
				// for style dimensions queries, a short delay can still be necessary
				setTimeout(callback, 7);
			}
		} else {
			var loadInterval = setInterval(function() {
				for (var i = 0; i < document.styleSheets.length; i++) {
					var sheet = document.styleSheets[i];
					if (sheet.href == link.href) {
						clearInterval(loadInterval);
						return callback();
					}
				}
			}, 10);
		}
		link.href = url;
		head.appendChild(link);
	}

	//>>excludeEnd('excludeRequireCss')
	cssAPI.normalize = function(name, normalize) {
		if (name.substr(name.length - 4, 4) == '.css')
			name = name.substr(0, name.length - 4);

		return normalize(name);
	}

	//>>excludeStart('excludeRequireCss', pragmas.excludeRequireCss)
	cssAPI.load = function(cssId, req, load, config) {

		(useImportLoad ? importLoad : linkLoad)(req.toUrl(cssId + '.css'), load);

	}

	//>>excludeEnd('excludeRequireCss')
	return cssAPI;
});