func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any],
                 fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {


    if let messageID = userInfo[gcmMessageIDKey] {
        print("Message ID: (messageID)")
        print("Estoy en 5")
    }
    print(userInfo)
    print("Estoy en 6")

    completionHandler(UIBackgroundFetchResult.newData)


    guard
        let aps = userInfo[AnyHashable("aps")]as? NSDictionary,
        let id = aps["idMensaje"] as? String

        else{

            return
    }

        let user = Auth.auth().currentUser
        let uid = user?.uid
        var ref: DatabaseReference!
        ref = Database.database().reference()

        ref.child("mensajes").child(id).child(uid!).child("recibido").setValue("ok")

        print("da recibido 6")



        let nav = UINavigationController()

        let principal:ViewControllerNotificacion = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "vcNotificaciones") as! ViewControllerNotificacion
        principal.idMensaje = id
        nav.viewControllers = [principal]
        self.window!.rootViewController = nav
        self.window?.makeKeyAndVisible()
        print("Estoy en prueba1")




    }