let instance = FIRInstanceID.instanceID()
_ = FIRInstanceID.delete(instance)
FIRInstanceID.instanceID().delete { (err:Error?) in
    if err != nil{
        print(err.debugDescription);
    } else {
        print("Token Deleted");
    }
}

if let token = FIRInstanceID.instanceID().token() {
    print("Token (token) fetched");
} else {
    print("Unable to fetch token");
}

FIRMessaging.messaging().connect { (error) in
    if (error != nil) {
        print("Error connecting to FCM. (error.debugDescription)")
    } else {
        print("Connected to FCM.")
    }
}

func registerFirebaseToken() {
    if let token = InstanceID.instanceID().token() {
        print("FIREBASE: Token (token) fetched")
    } else {
        print("FIREBASE: Unable to fetch token");
    }

    Messaging.messaging().shouldEstablishDirectChannel = true
}

func unregisterFirebaseToken(completion: @escaping (Bool)->()) {
    // Delete the Firebase instance ID
    InstanceID.instanceID().deleteID { (error) in
        if error != nil{
            print("FIREBASE: ", error.debugDescription);
            completion(false)
        } else {
            print("FIREBASE: Token Deleted");
            completion(true)
        }
    }
}

extension AppDelegate: MessagingDelegate {
    func messaging(_ messaging: Messaging, didRefreshRegistrationToken fcmToken: String) {
        registerFirebaseToken()
    }
}