Saving courses now works

background.js

@@ -1,6 +1,14 @@
 chrome.runtime.onMessage.addListener(function(request, sender, response) {
-	if(request.greeting == "hello") {
-		getSaved(request,sender,response);
+	if(request.command == "courseStorage") {
+		if(request.action == "add"){
+			add(request,sender,response);
+		}
+		if(request.action == "remove"){
+			remove(request,sender,response);
+		}
+	}
+	else if(request.command == "alreadyContains"){
+		alreadyContains(request.course,response);
 	}
 	else{
 		const xhr = new XMLHttpRequest();
@@ -16,10 +24,51 @@ chrome.runtime.onMessage.addListener(function(request, sender, response) {
 	return true;
 });
 
+ chrome.runtime.onInstalled.addListener(function() {
+ 	var arr = new Array();
+    chrome.storage.sync.set({savedCourses: arr}, function() {
+      console.log('initial course list');
+    });
+});
 
-function getSaved(request, sender, sendResponse) {
-    console.log(sender.tab ?
-                "from a content script:" + sender.tab.url :
-                "from the extension");
-      sendResponse({farewell: "goodbye"});
+function add(request, sender, sendResponse) {
+	var courses;
+	var response;
+	chrome.storage.sync.get('savedCourses', function(data) {
+		courses = data.savedCourses;
+		courses.push(request.course)
+		console.log(courses);
+		chrome.storage.sync.set({savedCourses: courses});
+		sendResponse({done:"Added: "+request.course.unique+request.course.coursename,label:"Remove Course -"});
+	});
+}
+function remove(request, sender, sendResponse) {
+	var courses;
+	var response;
+	chrome.storage.sync.get('savedCourses', function(data) {
+		courses = data.savedCourses;
+		var index = 0;
+		while(index<courses.length && courses[index].unique != request.course.unique){
+			index++;
+		}
+		courses.splice(index,1);
+		console.log(courses);
+		chrome.storage.sync.set({savedCourses: courses});
+		sendResponse({done:"removed: "+request.course.unique+request.course.coursename,label:"Add Course +"});
+	});
+}
+
+function alreadyContains(course,sendResponse){
+	chrome.storage.sync.get('savedCourses', function(data) {
+		courses = data.savedCourses;
+		var contains = false;
+		var i = 0;
+		while(i < courses.length && !contains){
+			if(courses[i].unique == course.unique){
+				contains = true;
+			}
+			i++;
+		}
+		sendResponse({alreadyContains: contains});
+	});
 }