Handle dark mode.

Why:

* The icon is hard to see in darkmode.

This change addresses the need by:

* Check current appearance when rendering the menu in order to know
  whether or not to display a dark or light icon.
* Add an observer to see when the apearance has changed and rerender the
  menu icon.

Side effects:

* The icon is now visible when in dark mode.

objective-octocat-notifications/AppDelegate.m

@@ -35,6 +35,10 @@ - (void)applicationWillFinishLaunching:(NSNotification *)notification
     NSURLCache *sharedCache = [[NSURLCache alloc] initWithMemoryCapacity:0
                                                             diskCapacity:0
                                                                 diskPath:nil];
+
+    [[NSDistributedNotificationCenter defaultCenter] addObserver:self selector:@selector(appearanceChanged:) name:@"AppleInterfaceThemeChangedNotification" object:nil];
+
+
     [NSURLCache setSharedURLCache:sharedCache];
 
     [[NSUserNotificationCenter defaultUserNotificationCenter] setDelegate:self];
@@ -43,6 +47,10 @@ - (void)applicationWillFinishLaunching:(NSNotification *)notification
     [[NSAppleEventManager sharedAppleEventManager] setEventHandler:self andSelector:@selector(handleGetURLEvent:withReplyEvent:) forEventClass:kInternetEventClass andEventID:kAEGetURL];
 }
 
+- (void)appearanceChanged:(NSNotification *)notify {
+    [_statusItemController setActiveStateFromNotificationsCount];
+}
+
 - (void)applicationDidFinishLaunching:(NSNotification *)notification
 {
     _haveAskedIfWeShouldAddToLoginItemsDefaultsKey = [NSString stringWithFormat:@"%@.haveAskedIfWeShouldAddToLoginItems", [[NSRunningApplication currentApplication] bundleIdentifier]];

objective-octocat-notifications/OonStatusBarController.h

@@ -16,6 +16,7 @@
 {
     NSStatusItem *statusItem;
     OonIcon *defaultIcon;
+    OonIcon *defaultDarkIcon;
     OonIcon *hasNotificationsIcon;
 }
 

objective-octocat-notifications/OonStatusBarController.m

@@ -16,6 +16,7 @@ - (id)init
     self = [super init];
     if (self) {
         defaultIcon = [OonIcon forStatusBarFrom:OonIconStatusBarDefault];
+        defaultDarkIcon = [OonIcon forStatusBarFrom:OonIconStatusBarActive];
         hasNotificationsIcon = [OonIcon forStatusBarFrom:OonIconStatusBarHasNotifications];
         statusItem = [[NSStatusBar systemStatusBar] statusItemWithLength:NSVariableStatusItemLength];
     }
@@ -35,7 +36,11 @@ - (void) setActiveStateTo:(BOOL) hasNotifications
     if (hasNotifications) {
         [statusItem setImage:hasNotificationsIcon];
     } else {
-        [statusItem setImage:defaultIcon];
+        if ([[[NSUserDefaults standardUserDefaults] stringForKey:@"AppleInterfaceStyle"] isEqualToString:@"Dark"]) {
+            [statusItem setImage:defaultDarkIcon];
+        } else {
+            [statusItem setImage:defaultIcon];
+        }
     }
 }