Make badge count accurate

Previously it would reset when refreshing the inbox. Now it tracks
changes to conversation unreadCounts.

Fixes #200

js/inbox_controller.js

@@ -30,6 +30,19 @@
     });
 
     inbox.on('change:active_at', inbox.sort);
+    inbox.on('change:unreadCount', function(model, count) {
+        var prev = model.previous('unreadCount');
+        if (count < prev) { // decreased
+            var newUnreadCount = textsecure.storage.getUnencrypted("unreadCount") - (prev - count);
+            if (newUnreadCount <= 0) {
+                newUnreadCount = 0;
+                extension.navigator.setBadgeText("");
+            } else {
+                extension.navigator.setBadgeText(newUnreadCount);
+            }
+            textsecure.storage.putUnencrypted("unreadCount", newUnreadCount);
+        }
+    });
 
     function fetch() {
         window.inbox.fetch({

js/index.js

@@ -23,7 +23,5 @@
         window.location = '/options.html';
     } else {
         new bg.Whisper.InboxView().$el.prependTo(bg.$('body',document));
-        bg.textsecure.storage.putUnencrypted("unreadCount", 0);
-        extension.navigator.setBadgeText("");
     }
 }());