@interface AppRoots : NSObject

// Normal use
+ (UITabBarController *)appRoot;

// Other uses
+ (UIPageViewController *)introRoot;
+ (UINavigationController *)loggedOutRoot;
+ (UIViewController *)upgradingDBRoot;
+ (UIViewController *)networkDownRoot;

@end

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    UIViewController *root = nil;

    if (/* logged in */) {
        root = [AppRoots appRoot];
    } else {
        root = [AppRoots introRoot];
    }

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.window.rootViewController = [TSAnimatedRootViewSwitcheroo switcherooWithRoot:root andDelegate:self];
    [self.window makeKeyAndVisible];

    return YES;
}

- (void)signOut {
  // Do some stuff
  [TSAnimatedRootViewSwitcheroo useRoot:[AppRoots loggedOutRoot] direction:TSSwitcherooAnimationDirectionReverse];
}

- (void)signIn {
  // Do some stuff
  [TSAnimatedRootViewSwitcheroo useRoot:[AppRoots appRoot] direction:TSSwitcherooAnimationDirectionForward];
}

- (id<UIViewControllerAnimatedTransitioning>)switcheroo:(TSAnimatedRootViewSwitcheroo *)switcheroo
                               animationControllerForDirection:(TSSwitcherooAnimationDirection)direction
                                            fromViewController:(UIViewController *)fromViewController
                                              toViewController:(UIViewController *)toViewController {

    // Let's use some awesome transitions from the VCTransitionsLibrary
    CEReversibleAnimationController *animator = [CENatGeoAnimationController new];
    animator.reverse = (direction == TSSwitcherooAnimationDirectionReverse);
    return animator;

    // If we want a Cube animation for login/logout, but a Flip animation for UpgradeDB => app
    // then we'd check the fromViewController/toViewController pairs and return the right animation.

    // Return nil for no animation.
}

@end