Mostly-Harmless/background.html

<script>
	var reddit_session = null;
	setBadgeDefaults();
	window.localStorage.clear();
	chrome.tabs.onUpdated.addListener(listenToTabs);
	chrome.tabs.onRemoved.addListener(cleanCache);
	chrome.cookies.get({url: 'http://reddit.com', name: 'reddit_session'}, function(cookie){
		reddit_session = cookie.value;
		console.log('cookie.value = ' + cookie.value);
	});
	
	function setBadgeDefaults(tabId) {
		chrome.browserAction.setBadgeBackgroundColor({
			color: [192,192,192,255] //r,g,b,a
		});
		chrome.browserAction.onClicked.removeListener(submitToReddit);
		if(tabId) {
			chrome.browserAction.setBadgeText({
				text: '?',
				tabId: tabId
			});
			chrome.browserAction.setTitle({
				title: 'Refresh the page to load data.',
				tabId: tabId
			});
		} else {
			chrome.browserAction.setBadgeText({
				text: '?',
			});
			chrome.browserAction.setTitle({
				title: 'Refresh the page to load data.'
			});
		}
	}
	function cleanCache() {
		// find old caches from localStorage and remove anything older than ___.
	}
	function listenToTabs(tabId,changeInfo,tab){
		if(changeInfo.status === 'loading') {
			grabData(tab.url,tabId);
		}
	}
	function grabData(url,tabId) {
		//check if the url has been cached recently
		if(window.localStorage.getItem(url) === null || JSON.parse(window.localStorage.getItem(url)).cachetime - new Date < -60000) {
			console.log('Loading from reddit api...');
			var reqUrl = 'http://www.reddit.com/api/info.json?url=' + encodeURI(url);
			var api = new XMLHttpRequest();
			api.open('GET',reqUrl,false);
			api.send(null);
			if(api.status !== 200) {
				console.error('Error loading API.\nURL: ' + reqUrl + '\nStatus: ' + api.status);
				console.log(api);
				setBadgeDefaults(tabId);
			}
			api.onload = prepareButton(JSON.parse(api.responseText),url,tabId);
		} else {
			console.log('Loading from cache...');
			prepareButton(JSON.parse(window.localStorage.getItem(url)).response,url,tabId);
		}
	}
	function prepareButton(response,pageUrl,tabId) {
		// add response to cache to reduce API calls
		if(window.localStorage.getItem(pageUrl) === null || JSON.parse(window.localStorage.getItem(pageUrl)).cachetime - new Date < -60000) {
			var toCache = new Object();
			toCache.cachetime = new Date();
			toCache.response = response;
			window.localStorage.setItem(pageUrl,JSON.stringify(toCache));
			delete toCache;
		}
		
		// counts submissions and prepare the browserAction button appropriately
		var numberOfSubmissions = response.data.children.length.toString();
		if(numberOfSubmissions > 0) {
			chrome.browserAction.setTitle({
				title: 'This page has been submitted to reddit ' + numberOfSubmissions + ' times.',
				tabId: tabId
			});
			chrome.browserAction.setBadgeText({
				text: numberOfSubmissions,
				tabId: tabId
			});
			chrome.browserAction.setPopup({
				popup: 'popup.html',
				tabId: tabId
			});
			chrome.browserAction.setBadgeBackgroundColor({
				color: [255,69,0,255], //r,g,b,a,
				tabId: tabId
			});
			chrome.browserAction.onClicked.removeListener(submitToReddit);
		} else {
			chrome.browserAction.setTitle({
				title: 'Submit this page to reddit',
				tabId: tabId
			});
			chrome.browserAction.setBadgeText({
				text: '',
				tabId: tabId
			});
			chrome.browserAction.setPopup({
				popup: '',
				tabId: tabId
			});
			chrome.browserAction.onClicked.removeListener(submitToReddit);
			chrome.browserAction.onClicked.addListener(submitToReddit);
		}
	}
	function submitToReddit(tab){
		chrome.tabs.create({
			url: 'http://www.reddit.com/submit?url=' + encodeURI(tab.url)
		});
	}
</script>