protected void onCreate()

in auth/src/main/java/com/firebase/ui/auth/ui/idp/WelcomeBackIdpPrompt.java [80:201]
103 lines of code
13 McCabe index (conditional complexity)

    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fui_welcome_back_idp_prompt_layout);

        mDoneButton = findViewById(R.id.welcome_back_idp_button);
        mProgressBar = findViewById(R.id.top_progress_bar);
        mPromptText = findViewById(R.id.welcome_back_idp_prompt);

        User existingUser = User.getUser(getIntent());
        IdpResponse requestedUserResponse = IdpResponse.fromResultIntent(getIntent());
        ViewModelProvider supplier = new ViewModelProvider(this);

        final LinkingSocialProviderResponseHandler handler =
                supplier.get(LinkingSocialProviderResponseHandler.class);
        handler.init(getFlowParams());
        if (requestedUserResponse != null) {
            handler.setRequestedSignInCredentialForEmail(
                    ProviderUtils.getAuthCredential(requestedUserResponse),
                    existingUser.getEmail());
        }

        final String providerId = existingUser.getProviderId();
        AuthUI.IdpConfig config =
                ProviderUtils.getConfigFromIdps(getFlowParams().providers, providerId);
        if (config == null) {
            finish(RESULT_CANCELED, IdpResponse.getErrorIntent(new FirebaseUiException(
                    ErrorCodes.DEVELOPER_ERROR,
                    "Firebase login unsuccessful."
                            + " Account linking failed due to provider not enabled by application: "
                            + providerId)));
            return;
        }


        String providerName;

        String genericOAuthProviderId = config.getParams()
                .getString(ExtraConstants.GENERIC_OAUTH_PROVIDER_ID);

        boolean useEmulator = getAuthUI().isUseEmulator();

        switch (providerId) {
            case GoogleAuthProvider.PROVIDER_ID:
                if (useEmulator) {
                    mProvider = supplier.get(GenericIdpAnonymousUpgradeLinkingHandler.class)
                            .initWith(GenericIdpSignInHandler.getGenericGoogleConfig());
                } else {
                    mProvider = supplier.get(GoogleSignInHandler.class).initWith(
                            new GoogleSignInHandler.Params(config, existingUser.getEmail()));
                }
                providerName = getString(R.string.fui_idp_name_google);
                break;
            case FacebookAuthProvider.PROVIDER_ID:
                if (useEmulator) {
                    mProvider = supplier.get(GenericIdpAnonymousUpgradeLinkingHandler.class)
                            .initWith(GenericIdpSignInHandler.getGenericFacebookConfig());
                } else {
                    mProvider = supplier.get(FacebookSignInHandler.class).initWith(config);
                }
                providerName = getString(R.string.fui_idp_name_facebook);
                break;
            default:
                if (TextUtils.equals(providerId, genericOAuthProviderId)) {
                    mProvider = supplier.get(GenericIdpAnonymousUpgradeLinkingHandler.class)
                            .initWith(config);
                    providerName = config.getParams()
                            .getString(ExtraConstants.GENERIC_OAUTH_PROVIDER_NAME);
                } else {
                    throw new IllegalStateException("Invalid provider id: " + providerId);
                }
        }

        mProvider.getOperation().observe(this, new ResourceObserver<IdpResponse>(this) {
            @Override
            protected void onSuccess(@NonNull IdpResponse response) {
                boolean isGenericIdp = getAuthUI().isUseEmulator()
                        || !AuthUI.SOCIAL_PROVIDERS.contains(response.getProviderType());

                if (isGenericIdp
                        && !response.hasCredentialForLinking()
                        && !handler.hasCredentialForLinking()) {
                    // Generic Idp does not return a credential - if this is not a linking flow,
                    // the user is already signed in and we are done.
                    finish(RESULT_OK, response.toIntent());
                    return;
                }
                handler.startSignIn(response);
            }

            @Override
            protected void onFailure(@NonNull Exception e) {
                handler.startSignIn(IdpResponse.from(e));
            }
        });

        mPromptText.setText(getString(
                R.string.fui_welcome_back_idp_prompt,
                existingUser.getEmail(),
                providerName));

        mDoneButton.setOnClickListener(view -> mProvider.startSignIn(getAuth(), WelcomeBackIdpPrompt.this, providerId));

        handler.getOperation().observe(this, new ResourceObserver<IdpResponse>(this) {
            @Override
            protected void onSuccess(@NonNull IdpResponse response) {
                finish(RESULT_OK, response.toIntent());
            }

            @Override
            protected void onFailure(@NonNull Exception e) {
                if (e instanceof FirebaseAuthAnonymousUpgradeException) {
                    IdpResponse response = ((FirebaseAuthAnonymousUpgradeException) e).getResponse();
                    finish(ErrorCodes.ANONYMOUS_UPGRADE_MERGE_CONFLICT, response.toIntent());
                } else {
                    finish(RESULT_CANCELED, IdpResponse.getErrorIntent(e));
                }
            }
        });

        TextView footerText = findViewById(R.id.email_footer_tos_and_pp_text);
        PrivacyDisclosureUtils.setupTermsOfServiceFooter(this, getFlowParams(), footerText);
    }