UIVIewController+UIAlertController.swift

import UIKit

extension UIViewController {
    
    func getForegroundAlertController() -> UIAlertController? {

        var viewController = UIApplication.sharedApplication().keyWindow?.rootViewController
        while let controller = viewController?.presentedViewController {
            if controller is UIAlertController {
                viewController = controller
                break
            }
        }
        
        guard let alert = viewController as? UIAlertController else {
            return nil
        }
        return alert
        
    }
}