private void handleSignInOperation()

in auth/src/main/java/com/firebase/ui/auth/ui/idp/AuthMethodPickerActivity.java [271:368]
78 lines of code
16 McCabe index (conditional complexity)

    private void handleSignInOperation(final IdpConfig idpConfig, View view) {
        ViewModelProvider supplier = new ViewModelProvider(this);
        final String providerId = idpConfig.getProviderId();
        final ProviderSignInBase<?> provider;

        AuthUI authUI = getAuthUI();

        switch (providerId) {
            case EMAIL_LINK_PROVIDER:
            case EmailAuthProvider.PROVIDER_ID:
                provider = supplier.get(EmailSignInHandler.class).initWith(null);
                break;
            case PhoneAuthProvider.PROVIDER_ID:
                provider = supplier.get(PhoneSignInHandler.class).initWith(idpConfig);
                break;
            case AuthUI.ANONYMOUS_PROVIDER:
                provider = supplier.get(AnonymousSignInHandler.class).initWith(getFlowParams());
                break;
            case GoogleAuthProvider.PROVIDER_ID:
                if (authUI.isUseEmulator()) {
                    provider = supplier.get(GenericIdpSignInHandler.class)
                            .initWith(GenericIdpSignInHandler.getGenericGoogleConfig());
                } else {
                    provider = supplier.get(GoogleSignInHandler.class).initWith(
                            new GoogleSignInHandler.Params(idpConfig));
                }
                break;
            case FacebookAuthProvider.PROVIDER_ID:
                if (authUI.isUseEmulator()) {
                    provider = supplier.get(GenericIdpSignInHandler.class)
                            .initWith(GenericIdpSignInHandler.getGenericFacebookConfig());
                } else {
                    provider = supplier.get(FacebookSignInHandler.class).initWith(idpConfig);
                }
                break;
            default:
                if (!TextUtils.isEmpty(
                        idpConfig.getParams().getString(GENERIC_OAUTH_PROVIDER_ID))) {
                    provider = supplier.get(GenericIdpSignInHandler.class).initWith(idpConfig);
                    break;
                }
                throw new IllegalStateException("Unknown provider: " + providerId);
        }

        mProviders.add(provider);

        provider.getOperation().observe(this, new ResourceObserver<IdpResponse>(this) {
            @Override
            protected void onSuccess(@NonNull IdpResponse response) {
                handleResponse(response);
            }

            @Override
            protected void onFailure(@NonNull Exception e) {
                if (e instanceof FirebaseAuthAnonymousUpgradeException) {
                    finish(RESULT_CANCELED, new Intent().putExtra(ExtraConstants.IDP_RESPONSE,
                            IdpResponse.from(e)));
                    return;
                }
                handleResponse(IdpResponse.from(e));
            }

            private void handleResponse(@NonNull IdpResponse response) {
                // If we're using the emulator then the social flows actually use Generic IDP
                // instead which means we shouldn't use the social response handler.
                boolean isSocialResponse = AuthUI.SOCIAL_PROVIDERS.contains(providerId)
                        && !getAuthUI().isUseEmulator();

                if (!response.isSuccessful()) {
                    // We have no idea what provider this error stemmed from so just forward
                    // this along to the handler.
                    mHandler.startSignIn(response);
                } else if (isSocialResponse) {
                    // Don't use the response's provider since it can be different than the one
                    // that launched the sign-in attempt. Ex: the email flow is started, but
                    // ends up turning into a Google sign-in because that account already
                    // existed. In the previous example, an extra sign-in would incorrectly
                    // started.
                    mHandler.startSignIn(response);
                } else {
                    // Email, phone, or generic: the credentials should have already been saved so
                    // simply move along.
                    // Anononymous sign in also does not require any other operations.
                    finish(response.isSuccessful() ? RESULT_OK : RESULT_CANCELED,
                            response.toIntent());
                }
            }
        });
        view.setOnClickListener(view1 -> {
            if (isOffline()) {
                Snackbar.make(findViewById(android.R.id.content), getString(R.string.fui_no_internet), Snackbar.LENGTH_SHORT).show();
                return;
            }

            provider.startSignIn(getAuth(), AuthMethodPickerActivity.this,
                    idpConfig.getProviderId());
        });
    }