add app notice

js/application.js

@@ -1,4 +1,18 @@
 // Wait till the browser is ready to render the game (avoids glitches)
 window.requestAnimationFrame(function () {
   new GameManager(4, KeyboardInputManager, HTMLActuator, LocalStorageManager);
+
+  // TODO: This code is in need of a refactor (along with the rest)
+  var storage     = new LocalStorageManager;
+  var noticeClose = document.querySelector(".notice-close-button");
+  var notice      = document.querySelector(".app-notice");
+  if (storage.getNoticeClosed()) {
+    notice.parentNode.removeChild(notice);
+  } else {
+    noticeClose.addEventListener("click", function () {
+      notice.parentNode.removeChild(notice);
+      storage.setNoticeClosed(true);
+      ga("send", "event", "notice", "closed");
+    });
+  }
 });

js/local_storage_manager.js

@@ -21,6 +21,7 @@ window.fakeStorage = {
 function LocalStorageManager() {
   this.bestScoreKey     = "bestScore";
   this.gameStateKey     = "gameState";
+  this.noticeClosedKey  = "noticeClosed";
 
   var supported = this.localStorageSupported();
   this.storage = supported ? window.localStorage : window.fakeStorage;
@@ -61,3 +62,11 @@ LocalStorageManager.prototype.setGameState = function (gameState) {
 LocalStorageManager.prototype.clearGameState = function () {
   this.storage.removeItem(this.gameStateKey);
 };
+
+LocalStorageManager.prototype.setNoticeClosed = function (noticeClosed) {
+  this.storage.setItem(this.noticeClosedKey, JSON.stringify(noticeClosed));
+};
+
+LocalStorageManager.prototype.getNoticeClosed = function () {
+  return JSON.parse(this.storage.getItem(this.noticeClosedKey) || "false");
+};