Youtube Login Api OAuth 2.0 flutter - flutter

Question

I've been trying for a bit to implement login of youtube channels on my app. but all I could do was google accounts with google_sign_in 4.5.1
has any of you implemented this feature and can give me an hint? youtube docs are terrible
edit:
here's the code
class AuthService {
String oAuthClientId = '**hidden**'; // not used?
static List<String> scopes = [
'email',
'https://www.googleapis.com/auth/youtube', // Youtube scope
];
final FirebaseAuth auth = FirebaseAuth.instance;
GoogleSignIn googleSignIn = GoogleSignIn(
scopes: scopes,
);
Future<FirebaseUser> login() async {
final GoogleSignInAccount googleSignInAccount = await googleSignIn.signIn();
final GoogleSignInAuthentication googleSignInAuthentication = await googleSignInAccount.authentication;
final AuthCredential credential = GoogleAuthProvider.getCredential(
accessToken: googleSignInAuthentication.accessToken,
idToken: googleSignInAuthentication.idToken,
);
final token = googleSignInAuthentication.accessToken;
final AuthResult authResult = await auth.signInWithCredential(credential);
final FirebaseUser user = authResult.user;
assert(!user.isAnonymous);
assert(await user.getIdToken() != null);
final FirebaseUser currentUser = await auth.currentUser();
assert(user.uid == currentUser.uid);
var client = new http.Client();
return currentUser;
}
void signOut() {
auth.signOut();
googleSignIn.disconnect();
}
Future<FirebaseUser> getUser() async{
final FirebaseUser user = await auth.currentUser();
return user;
}
}

Answer 1

To display your youtube channels, you'll need to add the youtube scope https://www.googleapis.com/auth/youtube to your google login.
Prior to this, you must've setup enabled the Youtube api from your developer console. Read the Youtube API documentation for more information
Example login code:
login() async {
GoogleSignIn googleSignIn = GoogleSignIn(
scopes: [
'email',
'https://www.googleapis.com/auth/youtube', // Youtube scope
],
);
final GoogleSignInAccount googleSignInAccount = await googleSignIn.signIn();
final GoogleSignInAuthentication googleSignInAuthentication =
await googleSignInAccount.authentication;
final AuthCredential credential = GoogleAuthProvider.getCredential(
accessToken: googleSignInAuthentication.accessToken,
idToken: googleSignInAuthentication.idToken,
);
// You'll need this token to call the Youtube API. It expires every 30 minutes.
final token = googleSignInAuthentication.accessToken;
final AuthResult authResult = await auth.signInWithCredential(credential);
final FirebaseUser user = authResult.user;
assert(!user.isAnonymous);
assert(await user.getIdToken() != null);
final FirebaseUser currentUser = await auth.currentUser();
assert(user.uid == currentUser.uid);
}