feat(auth): TOTP (time-based one-time password) support for multi-factor authentication

packages/firebase_auth/firebase_auth/android/src/main/java/io/flutter/plugins/firebase/auth/FlutterFirebaseAuthPlugin.java

@@ -57,13 +57,19 @@ public class FlutterFirebaseAuthPlugin
   private final FlutterFirebaseAuthUser firebaseAuthUser = new FlutterFirebaseAuthUser();
   private final FlutterFirebaseMultiFactor firebaseMultiFactor = new FlutterFirebaseMultiFactor();
 
+  private final FlutterFirebaseTotpMultiFactor firebaseTotpMultiFactor =
+      new FlutterFirebaseTotpMultiFactor();
+  private final FlutterFirebaseTotpSecret firebaseTotpSecret = new FlutterFirebaseTotpSecret();
+
   private void initInstance(BinaryMessenger messenger) {
     registerPlugin(METHOD_CHANNEL_NAME, this);
     channel = new MethodChannel(messenger, METHOD_CHANNEL_NAME);
     GeneratedAndroidFirebaseAuth.FirebaseAuthHostApi.setup(messenger, this);
     GeneratedAndroidFirebaseAuth.FirebaseAuthUserHostApi.setup(messenger, firebaseAuthUser);
     GeneratedAndroidFirebaseAuth.MultiFactorUserHostApi.setup(messenger, firebaseMultiFactor);
     GeneratedAndroidFirebaseAuth.MultiFactoResolverHostApi.setup(messenger, firebaseMultiFactor);
+    GeneratedAndroidFirebaseAuth.MultiFactorTotpHostApi.setup(messenger, firebaseTotpMultiFactor);
+    GeneratedAndroidFirebaseAuth.MultiFactorTotpSecretHostApi.setup(messenger, firebaseTotpSecret);
 
     this.messenger = messenger;
   }
@@ -82,6 +88,8 @@ public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
     GeneratedAndroidFirebaseAuth.FirebaseAuthUserHostApi.setup(messenger, null);
     GeneratedAndroidFirebaseAuth.MultiFactorUserHostApi.setup(messenger, null);
     GeneratedAndroidFirebaseAuth.MultiFactoResolverHostApi.setup(messenger, null);
+    GeneratedAndroidFirebaseAuth.MultiFactorTotpHostApi.setup(messenger, null);
+    GeneratedAndroidFirebaseAuth.MultiFactorTotpSecretHostApi.setup(messenger, null);
 
     channel = null;
     messenger = null;

packages/firebase_auth/firebase_auth/android/src/main/java/io/flutter/plugins/firebase/auth/FlutterFirebaseMultiFactor.java

@@ -37,6 +37,8 @@ public class FlutterFirebaseMultiFactor
   // Map an id to a MultiFactorResolver object.
   static final Map<String, MultiFactorResolver> multiFactorResolverMap = new HashMap<>();
 
+  static final Map<String, MultiFactorAssertion> multiFactorAssertionMap = new HashMap<>();
+
   MultiFactor getAppMultiFactor(@NonNull GeneratedAndroidFirebaseAuth.PigeonFirebaseApp app)
       throws FirebaseNoSignedInUserException {
     final FirebaseUser currentUser = FlutterFirebaseAuthUser.getCurrentUserFromPigeon(app);
@@ -89,6 +91,37 @@ public void enrollPhone(
             });
   }
 
+  @Override
+  public void enrollTotp(
+      @NonNull GeneratedAndroidFirebaseAuth.PigeonFirebaseApp app,
+      @NonNull String assertionId,
+      @Nullable String displayName,
+      @NonNull GeneratedAndroidFirebaseAuth.Result<Void> result) {
+    final MultiFactor multiFactor;
+    try {
+      multiFactor = getAppMultiFactor(app);
+    } catch (FirebaseNoSignedInUserException e) {
+      result.error(e);
+      return;
+    }
+
+    final MultiFactorAssertion multiFactorAssertion = multiFactorAssertionMap.get(assertionId);
+
+    assert multiFactorAssertion != null;
+    multiFactor
+        .enroll(multiFactorAssertion, displayName)
+        .addOnCompleteListener(
+            task -> {
+              if (task.isSuccessful()) {
+                result.success(null);
+              } else {
+                result.error(
+                    FlutterFirebaseAuthPluginException.parserExceptionToFlutter(
+                        task.getException()));
+              }
+            });
+  }
+
   @Override
   public void getSession(
       @NonNull GeneratedAndroidFirebaseAuth.PigeonFirebaseApp app,
@@ -176,7 +209,8 @@ public void getEnrolledFactors(
   @Override
   public void resolveSignIn(
       @NonNull String resolverId,
-      @NonNull GeneratedAndroidFirebaseAuth.PigeonPhoneMultiFactorAssertion assertion,
+      @Nullable GeneratedAndroidFirebaseAuth.PigeonPhoneMultiFactorAssertion assertion,
+      @Nullable String totpAssertionId,
       @NonNull
           GeneratedAndroidFirebaseAuth.Result<GeneratedAndroidFirebaseAuth.PigeonUserCredential>
               result) {
@@ -189,11 +223,16 @@ public void resolveSignIn(
       return;
     }
 
-    PhoneAuthCredential credential =
-        PhoneAuthProvider.getCredential(
-            assertion.getVerificationId(), assertion.getVerificationCode());
+    MultiFactorAssertion multiFactorAssertion;
 
-    MultiFactorAssertion multiFactorAssertion = PhoneMultiFactorGenerator.getAssertion(credential);
+    if (assertion != null) {
+      PhoneAuthCredential credential =
+          PhoneAuthProvider.getCredential(
+              assertion.getVerificationId(), assertion.getVerificationCode());
+      multiFactorAssertion = PhoneMultiFactorGenerator.getAssertion(credential);
+    } else {
+      multiFactorAssertion = multiFactorAssertionMap.get(totpAssertionId);
+    }
 
     resolver
         .resolveSignIn(multiFactorAssertion)

packages/firebase_auth/firebase_auth/android/src/main/java/io/flutter/plugins/firebase/auth/FlutterFirebaseTotpMultiFactor.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2023, the Chromium project authors.  Please see the AUTHORS file
+ * for details. All rights reserved. Use of this source code is governed by a
+ * BSD-style license that can be found in the LICENSE file.
+ */
+
+package io.flutter.plugins.firebase.auth;
+
+import androidx.annotation.NonNull;
+import com.google.firebase.auth.MultiFactorSession;
+import com.google.firebase.auth.TotpMultiFactorAssertion;
+import com.google.firebase.auth.TotpMultiFactorGenerator;
+import com.google.firebase.auth.TotpSecret;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+
+public class FlutterFirebaseTotpMultiFactor
+    implements GeneratedAndroidFirebaseAuth.MultiFactorTotpHostApi {
+
+  // Map an app id to a map of user id to a TotpSecret object.
+  static final Map<String, TotpSecret> multiFactorSecret = new HashMap<>();
+
+  @Override
+  public void generateSecret(
+      @NonNull String sessionId,
+      @NonNull
+          GeneratedAndroidFirebaseAuth.Result<GeneratedAndroidFirebaseAuth.PigeonTotpSecret>
+              result) {
+    MultiFactorSession multiFactorSession =
+        FlutterFirebaseMultiFactor.multiFactorSessionMap.get(sessionId);
+
+    assert multiFactorSession != null;
+    TotpMultiFactorGenerator.generateSecret(multiFactorSession)
+        .addOnCompleteListener(
+            task -> {
+              if (task.isSuccessful()) {
+                TotpSecret secret = task.getResult();
+                multiFactorSecret.put(secret.getSharedSecretKey(), secret);
+                result.success(
+                    new GeneratedAndroidFirebaseAuth.PigeonTotpSecret.Builder()
+                        .setCodeIntervalSeconds((long) secret.getCodeIntervalSeconds())
+                        .setCodeLength((long) secret.getCodeLength())
+                        .setSecretKey(secret.getSharedSecretKey())
+                        .setHashingAlgorithm(secret.getHashAlgorithm())
+                        .setEnrollmentCompletionDeadline(secret.getEnrollmentCompletionDeadline())
+                        .build());
+              } else {
+                result.error(
+                    FlutterFirebaseAuthPluginException.parserExceptionToFlutter(
+                        task.getException()));
+              }
+            });
+  }
+
+  @Override
+  public void getAssertionForEnrollment(
+      @NonNull String secretKey,
+      @NonNull String oneTimePassword,
+      @NonNull GeneratedAndroidFirebaseAuth.Result<String> result) {
+    final TotpSecret secret = multiFactorSecret.get(secretKey);
+
+    assert secret != null;
+    TotpMultiFactorAssertion assertion =
+        TotpMultiFactorGenerator.getAssertionForEnrollment(secret, oneTimePassword);
+    String assertionId = UUID.randomUUID().toString();
+    FlutterFirebaseMultiFactor.multiFactorAssertionMap.put(assertionId, assertion);
+    result.success(assertionId);
+  }
+
+  @Override
+  public void getAssertionForSignIn(
+      @NonNull String enrollmentId,
+      @NonNull String oneTimePassword,
+      @NonNull GeneratedAndroidFirebaseAuth.Result<String> result) {
+    TotpMultiFactorAssertion assertion =
+        TotpMultiFactorGenerator.getAssertionForSignIn(enrollmentId, oneTimePassword);
+    String assertionId = UUID.randomUUID().toString();
+    FlutterFirebaseMultiFactor.multiFactorAssertionMap.put(assertionId, assertion);
+    result.success(assertionId);
+  }
+}

packages/firebase_auth/firebase_auth/android/src/main/java/io/flutter/plugins/firebase/auth/FlutterFirebaseTotpSecret.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2023, the Chromium project authors.  Please see the AUTHORS file
+ * for details. All rights reserved. Use of this source code is governed by a
+ * BSD-style license that can be found in the LICENSE file.
+ */
+
+package io.flutter.plugins.firebase.auth;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import com.google.firebase.auth.TotpSecret;
+
+public class FlutterFirebaseTotpSecret
+    implements GeneratedAndroidFirebaseAuth.MultiFactorTotpSecretHostApi {
+
+  @Override
+  public void generateQrCodeUrl(
+      @NonNull String secretKey,
+      @Nullable String accountName,
+      @Nullable String issuer,
+      @NonNull GeneratedAndroidFirebaseAuth.Result<String> result) {
+    final TotpSecret secret = FlutterFirebaseTotpMultiFactor.multiFactorSecret.get(secretKey);
+
+    assert secret != null;
+    if (accountName == null || issuer == null) {
+      result.success(secret.generateQrCodeUrl());
+      return;
+    }
+    result.success(secret.generateQrCodeUrl(accountName, issuer));
+  }
+
+  @Override
+  public void openInOtpApp(
+      @NonNull String secretKey,
+      @NonNull String qrCodeUrl,
+      @NonNull GeneratedAndroidFirebaseAuth.Result<Void> result) {
+    final TotpSecret secret = FlutterFirebaseTotpMultiFactor.multiFactorSecret.get(secretKey);
+    assert secret != null;
+    secret.openInOtpApp(qrCodeUrl);
+    result.success(null);
+  }
+}