import 'package:desktop_webview_auth/desktop_webview_auth.dart';
import 'package:desktop_webview_auth/apple.dart';
import 'package:firebase_auth/firebase_auth.dart';  

final args = AppleSignInArgs(
    clientId: "your-service-id", //Services ID used as the web application identifier
    redirectUri: "https://your-project.firebaseapp.com/__/auth/handler",
);

try {
    final result = await DesktopWebviewAuth.signIn(args);
    if (result == null || result.idToken == null) {
      throw Exception("Authorize process terminated");
    }
} catch (err) {
    // something went wrong
}

final credential = OAuthProvider("apple.com").credential(
    idToken: result.idToken!,
    rawNonce: args.nonce,
);

FirebaseAuth.instance.signInWithCredential(credential);