import UIKit

public extension UIViewController {
    func topMostViewController() -> UIViewController {
        if presentedViewController == nil {
            return self
        }

        if let navigation = presentedViewController as? UINavigationController {
            return navigation.visibleViewController!.topMostViewController()
        }

        if let tab = presentedViewController as? UITabBarController {
            if let selectedTab = tab.selectedViewController {
                return selectedTab.topMostViewController()
            }
            return tab.topMostViewController()
        }

        return presentedViewController!.topMostViewController()
    }
}