[CLEANUP] Refactor various classes (#678)

* Do a whole bunch of refactoring

* Use Builder interface in AuthUI.java

* Add safety net in IdpResponse.Builder#build()

* Fix refactor mistake

* Also include GitHub in safety net

* Cleanup tests

* Fix broken tests

* Fix more refactor mistakes

* Fix broken test

* Cleanup

* Remove unnecessary builder interface

* Remove lazy enum singleton

Author: SUPERCILEX

app/src/main/java/com/firebase/uidemo/auth/AuthUiActivity.java

@@ -133,6 +133,7 @@ public void onCreate(Bundle savedInstanceState) {
         if (auth.getCurrentUser() != null) {
             startSignedInActivity(null);
             finish();
+            return;
         }
 
         if (!isGoogleConfigured()) {

app/src/main/java/com/firebase/uidemo/auth/SignedInActivity.java

@@ -293,10 +293,10 @@ public static Intent createIntent(
             Context context,
             IdpResponse idpResponse,
             SignedInConfig signedInConfig) {
-        Intent in = IdpResponse.getIntent(idpResponse);
-        in.setClass(context, SignedInActivity.class);
-        in.putExtra(EXTRA_SIGNED_IN_CONFIG, signedInConfig);
-        return in;
+        Intent startIntent = idpResponse == null ? new Intent() : idpResponse.toIntent();
+
+        return startIntent.setClass(context, SignedInActivity.class)
+                .putExtra(EXTRA_SIGNED_IN_CONFIG, signedInConfig);
     }
 
     @Override

auth/src/main/java/com/firebase/ui/auth/IdpResponse.java

@@ -19,8 +19,14 @@
 import android.os.Parcelable;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.support.annotation.RestrictTo;
+import android.text.TextUtils;
 
 import com.firebase.ui.auth.ui.ExtraConstants;
+import com.google.firebase.auth.FacebookAuthProvider;
+import com.google.firebase.auth.GithubAuthProvider;
+import com.google.firebase.auth.GoogleAuthProvider;
+import com.google.firebase.auth.TwitterAuthProvider;
 
 /**
  * A container that encapsulates the result of authenticating with an Identity Provider.
@@ -36,22 +42,6 @@ private IdpResponse(int errorCode) {
         this(null, null, null, null, errorCode);
     }
 
-    public IdpResponse(@NonNull String providerId, @NonNull String email) {
-        this(providerId, email, null, null, ResultCodes.OK);
-    }
-
-    public IdpResponse(@NonNull String providerId, @NonNull String email, @NonNull String token) {
-        this(providerId, email, token, null, ResultCodes.OK);
-    }
-
-    public IdpResponse(
-            @NonNull String providerId,
-            @NonNull String email,
-            @NonNull String token,
-            @NonNull String secret) {
-        this(providerId, email, token, secret, ResultCodes.OK);
-    }
-
     private IdpResponse(
             String providerId,
             String email,
@@ -80,24 +70,28 @@ public static IdpResponse fromResultIntent(Intent resultIntent) {
         }
     }
 
-    public static Intent getIntent(IdpResponse response) {
-        return new Intent().putExtra(ExtraConstants.EXTRA_IDP_RESPONSE, response);
+    @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
+    public static Intent getErrorCodeIntent(int errorCode) {
+        return new IdpResponse(errorCode).toIntent();
     }
 
-    public static Intent getErrorCodeIntent(int errorCode) {
-        return getIntent(new IdpResponse(errorCode));
+    @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
+    public Intent toIntent() {
+        return new Intent().putExtra(ExtraConstants.EXTRA_IDP_RESPONSE, this);
     }
 
     /**
      * Get the type of provider. e.g. {@link AuthUI#GOOGLE_PROVIDER}
      */
+    @NonNull
     public String getProviderType() {
         return mProviderId;
     }
 
     /**
      * Get the email used to sign in.
      */
+    @Nullable
     public String getEmail() {
         return mEmail;
     }
@@ -156,4 +150,45 @@ public IdpResponse[] newArray(int size) {
             return new IdpResponse[size];
         }
     };
+
+    @RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
+    public static class Builder {
+        private String mProviderId;
+        private String mEmail;
+        private String mToken;
+        private String mSecret;
+
+        public Builder(@NonNull String providerId, @Nullable String email) {
+            mProviderId = providerId;
+            mEmail = email;
+        }
+
+        public Builder setToken(String token) {
+            mToken = token;
+            return this;
+        }
+
+        public Builder setSecret(String secret) {
+            mSecret = secret;
+            return this;
+        }
+
+        public IdpResponse build() {
+            if ((mProviderId.equalsIgnoreCase(GoogleAuthProvider.PROVIDER_ID)
+                    || mProviderId.equalsIgnoreCase(FacebookAuthProvider.PROVIDER_ID)
+                    || mProviderId.equalsIgnoreCase(TwitterAuthProvider.PROVIDER_ID)
+                    || mProviderId.equalsIgnoreCase(GithubAuthProvider.PROVIDER_ID))
+                    && TextUtils.isEmpty(mToken)) {
+                throw new IllegalStateException(
+                        "Token cannot be null when using a non-email provider.");
+            }
+            if (mProviderId.equalsIgnoreCase(TwitterAuthProvider.PROVIDER_ID)
+                    && TextUtils.isEmpty(mSecret)) {
+                throw new IllegalStateException(
+                        "Secret cannot be null when using the Twitter provider.");
+            }
+
+            return new IdpResponse(mProviderId, mEmail, mToken, mSecret, ResultCodes.OK);
+        }
+    }
 }

auth/src/main/java/com/firebase/ui/auth/provider/FacebookProvider.java

@@ -19,6 +19,7 @@
 import android.content.Intent;
 import android.os.Bundle;
 import android.support.annotation.LayoutRes;
+import android.support.annotation.Nullable;
 import android.support.annotation.StyleRes;
 import android.util.Log;
 
@@ -182,18 +183,17 @@ public void onError(FacebookException error) {
         onFailure(extra);
     }
 
-    private IdpResponse createIdpResponse(String email, LoginResult loginResult) {
-        return new IdpResponse(
-                FacebookAuthProvider.PROVIDER_ID,
-                email,
-                loginResult.getAccessToken().getToken());
-    }
-
-    private void onSuccess(String email, LoginResult loginResult) {
+    private void onSuccess(@Nullable String email, LoginResult loginResult) {
         gcCallbackManager();
         mCallbackObject.onSuccess(createIdpResponse(email, loginResult));
     }
 
+    private IdpResponse createIdpResponse(@Nullable String email, LoginResult loginResult) {
+        return new IdpResponse.Builder(FacebookAuthProvider.PROVIDER_ID, email)
+                .setToken(loginResult.getAccessToken().getToken())
+                .build();
+    }
+
     private void onFailure(Bundle bundle) {
         gcCallbackManager();
         mCallbackObject.onFailure(bundle);

auth/src/main/java/com/firebase/ui/auth/provider/GoogleProvider.java

@@ -127,8 +127,9 @@ public void disconnect() {
     }
 
     private IdpResponse createIdpResponse(GoogleSignInAccount account) {
-        return new IdpResponse(
-                GoogleAuthProvider.PROVIDER_ID, account.getEmail(), account.getIdToken());
+        return new IdpResponse.Builder(GoogleAuthProvider.PROVIDER_ID, account.getEmail())
+                .setToken(account.getIdToken())
+                .build();
     }
 
     @Override

auth/src/main/java/com/firebase/ui/auth/provider/TwitterProvider.java

@@ -120,11 +120,10 @@ private void onSuccess(IdpResponse response) {
         }
 
         private IdpResponse createIdpResponse(String email) {
-            return new IdpResponse(
-                    TwitterAuthProvider.PROVIDER_ID,
-                    email,
-                    mTwitterSession.getAuthToken().token,
-                    mTwitterSession.getAuthToken().secret);
+            return new IdpResponse.Builder(TwitterAuthProvider.PROVIDER_ID, email)
+                    .setToken(mTwitterSession.getAuthToken().token)
+                    .setSecret(mTwitterSession.getAuthToken().secret)
+                    .build();
         }
     }
 }

auth/src/main/java/com/firebase/ui/auth/ui/BaseHelper.java

@@ -80,16 +80,8 @@ public boolean isProgressDialogShowing() {
         return mProgressDialog != null && mProgressDialog.isShowing();
     }
 
-    public String getAppName() {
-        return mFlowParams.appName;
-    }
-
-    public FirebaseApp getFirebaseApp() {
-        return FirebaseApp.getInstance(mFlowParams.appName);
-    }
-
     public FirebaseAuth getFirebaseAuth() {
-        return FirebaseAuth.getInstance(getFirebaseApp());
+        return FirebaseAuth.getInstance(FirebaseApp.getInstance(mFlowParams.appName));
     }
 
     public CredentialsApi getCredentialsApi() {
@@ -104,22 +96,14 @@ public SaveSmartLock getSaveSmartLockInstance(FragmentActivity activity) {
         return SaveSmartLock.getInstance(activity, getFlowParams());
     }
 
-    public void saveCredentialsOrFinish(
-            @Nullable SaveSmartLock saveSmartLock,
-            Activity activity,
-            FirebaseUser firebaseUser,
-            @NonNull IdpResponse response) {
-        saveCredentialsOrFinish(saveSmartLock, activity, firebaseUser, null, response);
-    }
-
     public void saveCredentialsOrFinish(
             @Nullable SaveSmartLock saveSmartLock,
             Activity activity,
             FirebaseUser firebaseUser,
             @Nullable String password,
             IdpResponse response) {
         if (saveSmartLock == null) {
-            finishActivity(activity, ResultCodes.OK, IdpResponse.getIntent(response));
+            finishActivity(activity, ResultCodes.OK, response.toIntent());
         } else {
             saveSmartLock.saveCredentialsOrFinish(
                     firebaseUser,

auth/src/main/java/com/firebase/ui/auth/ui/FlowParameters.java

@@ -52,11 +52,9 @@ public class FlowParameters implements Parcelable {
 
     public final boolean allowNewEmailAccounts;
 
-    public final boolean isReauth;
-
     @Nullable
     public final String reauthReason;
-
+    public final boolean isReauth;
 
     public FlowParameters(
             @NonNull String appName,

auth/src/main/java/com/firebase/ui/auth/ui/User.java

@@ -79,7 +79,7 @@ public void writeToParcel(@NonNull Parcel dest, int flags) {
         dest.writeParcelable(mPhotoUri, flags);
     }
 
-    public static final class Builder {
+    public static class Builder {
         private String mEmail;
         private String mName;
         private String mProvider;

auth/src/main/java/com/firebase/ui/auth/ui/accountlink/WelcomeBackIdpPrompt.java

@@ -161,7 +161,7 @@ public void onSuccess(AuthResult result) {
                                                 TAG, "Error signing in with previous credential " + idpResponse.getProviderType()))
                                         .addOnCompleteListener(new FinishListener(idpResponse));
                             } else {
-                                finish(ResultCodes.OK, IdpResponse.getIntent(idpResponse));
+                                finish(ResultCodes.OK, idpResponse.toIntent());
                             }
                         }
                     })
@@ -200,7 +200,7 @@ private class FinishListener implements OnCompleteListener<AuthResult> {
         }
 
         public void onComplete(@NonNull Task task) {
-            finish(ResultCodes.OK, IdpResponse.getIntent(mIdpResponse));
+            finish(ResultCodes.OK, mIdpResponse.toIntent());
         }
     }
 }