Apple Sign in

I have tried to implement apple sign in as an authentication provider, am having an issues for
1 Not navigating to the next page
2. It seems is not fetching any data am requesting.
Below is the code
using apple_sign_in 0.1.0 from pub.dev

Future<void> _ensureLoggedIn(BuildContext context) async {
  print('[_ensureLoggedIn] START');

  GoogleSignInAccount user = googleSignIn.currentUser;
  if (user == null) {
    print('[_ensureLoggedIn] user == null');
    print('[_ensureLoggedIn] [signInSilently] START');
    user = await googleSignIn.signInSilently();
    print('[_ensureLoggedIn] [signInSilently] DONE');
  }

  if (user == null) {
    print('[_ensureLoggedIn] user == null');
    print('[_ensureLoggedIn] [signIn] START');
    await googleSignIn.signIn().then((_) {
      tryCreateUserRecord(context);
    });
    print('[_ensureLoggedIn] [signIn] DONE');
  }

  if (await auth.currentUser() == null) {

    print('[_ensureLoggedIn] auth.currentUser() == null');
    print('[_ensureLoggedIn] [googleSignIn.currentUser.authentication] START');


    GoogleSignInAuthentication credentials = await googleSignIn.currentUser.authentication;
    final GoogleSignInAccount googleUser = await googleSignIn.signIn();
    final GoogleSignInAuthentication googleAuth = await googleUser.authentication;

print('[_ensureLoggedIn] [googleSignIn.currentUser.authentication] DONE');
    print('[_ensureLoggedIn] [signInWithGoogle] START');
  final AuthCredential credential = GoogleAuthProvider.getCredential(
      accessToken: googleAuth.accessToken,
      idToken: googleAuth.idToken,
    );
 return(await auth.signInWithCredential(credential)).user.uid;
  }
print('[_ensureLoggedIn] DONE');
}
Future<void> _silentLogin(BuildContext context) async {
  GoogleSignInAccount user = googleSignIn.currentUser;
if (user == null) {
    user = await googleSignIn.signInSilently();
    await tryCreateUserRecord(context);
  }
 if (await auth.currentUser() == null && user != null) {
    final GoogleSignInAccount googleUser = await googleSignIn.signIn();
    final GoogleSignInAuthentication googleAuth = await googleUser
        .authentication;
   final AuthCredential credential = GoogleAuthProvider.getCredential(
      accessToken: googleAuth.accessToken,
      idToken: googleAuth.idToken,
    );
    await auth.signInWithCredential(credential);
  }
}

// APPLE
Future<void> signInWithApple(BuildContext context) async {
  final AuthorizationResult result = await AppleSignIn.performRequests([
    AppleIdRequest(requestedScopes: [Scope.email, Scope.fullName])
  ]);
switch (result.status) {
    case AuthorizationStatus.authorized:
 // Store user ID
      await FlutterSecureStorage()
          .write(key: "userId", value: result.credential.user);
       final AppleIdCredential _auth = result.credential;
      final OAuthProvider oAuthProvider = new OAuthProvider(providerId: "apple.com");
     final AuthCredential credential = oAuthProvider.getCredential(
        idToken: String.fromCharCodes(_auth.identityToken),
        accessToken: String.fromCharCodes(_auth.authorizationCode),
      );
 await auth.signInWithCredential(credential);
// update the user information
      if (_auth.fullName != null) {
        auth.currentUser().then( (value) async {
          UserUpdateInfo user = UserUpdateInfo();
          user.displayName = "${_auth.fullName.givenName} ${_auth.fullName.familyName}";
          await value.updateProfile(user);
        });
      }

      break;
 case AuthorizationStatus.error:
      print("Sign In Failed ${result.error.localizedDescription}");
      break;
case AuthorizationStatus.cancelled:
      print("User Cancelled");
      break;
  }
}
tryCreateUserRecord(BuildContext context) async {
  GoogleSignInAccount user = googleSignIn.currentUser;
  if (user == null) {
    return null;
  }
  DocumentSnapshot userRecord = await ref.document(user.id).get();
  if (userRecord.data == null) {
    // no user record exists, time to create
 String userName = await Navigator.push( context,
      // We'll create the SelectionScreen in the next step!
      MaterialPageRoute(
          builder: (context) => Center(
                child: Scaffold(
                    appBar: AppBar(
                      leading: Container(),
                      title: Text('Fill out missing data',
                          style: TextStyle(
                              color: Colors.black,
                              fontWeight: FontWeight.bold)),
                      backgroundColor: Colors.white,
                    ),
                    body: ListView(
                      children: <Widget>[
                         Container(
                          child: CreateAccount(),
                        ),
                      ],
                    )),
              )),
 );
 if (userName != null || userName.length != 0){
      ref.document(user.id).setData({
        "id": user.id,
        "username": userName,
        "photoUrl": user.photoUrl,
        "email": user.email,
        "displayName": user.displayName,
      });
    }
  }
 currentUserModel = User.fromDocument(userRecord);
}
 and separate container for 
AppleSignInButton(
               type: ButtonType.signIn,
                cornerRadius: 6.0,
                 onPressed: () async {
                await signInWithApple( context );
                Navigator.push (context ,MaterialPageRoute(
                    builder: (_) =>
                        HomePage()));
              },

Please any help or any light something on the codes would be appreciated.
Thanks

Start by tracing signInWithApple and the AppleSignInButton callback, then compare their authentication and navigation flow with _ensureLoggedIn and _silentLogin. Check how auth.currentUser, the Apple credential, and the Firestore user record are handled. Done means authorized Apple sign-in completes, reaches HomePage, and retrieves or creates the expected user data.