GMiOS/app/UIApplcation.swift

// Copyright (C) 2016 Inigo Valentin
//
// This file is part of the Gasteizko Margolariak IOS app.
//
// The Gasteizko Margolariak IOS app is free software: you can
// redistribute it and/or modify it under the terms of the
// GNU General Public License as published by the Free Software
// Foundation, either version 3 of the License, or (at your
// option) any later version.
//
// The Gasteizko Margolariak IOS app is distributed in the
// hope that it will be useful, but WITHOUT ANY WARRANTY;
// without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
// Public License for more details.
//
// You should have received a copy of the GNU General Public
// License along with the Gasteizko Margolariak IOS app.
// If not, see <http://www.gnu.org/licenses/>.

import Foundation
import UIKit

/**
Extension of UIApplication to get the root view controller.
*/
extension UIApplication {
	
	/**
	Gets the top level controller.
	:return: Top level view controller.
	*/
	class func topViewController(controller: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {
		if let navigationController = controller as? UINavigationController {
			return topViewController(controller: navigationController.visibleViewController)
		}
		if let tabController = controller as? UITabBarController {
			if let selected = tabController.selectedViewController {
				return topViewController(controller: selected)
			}
		}
		if let presented = controller?.presentedViewController {
			return topViewController(controller: presented)
		}
		return controller
	}
}