feat: MFA Screens

Author: Lyokone

auth/src/main/java/com/firebase/ui/auth/compose/FirebaseAuthUI.kt

@@ -163,7 +163,18 @@ class FirebaseAuthUI private constructor(
         val firebaseAuthFlow = callbackFlow {
             // Set initial state based on current auth state
             val initialState = auth.currentUser?.let { user ->
-                AuthState.Success(result = null, user = user, isNewUser = false)
+                // Check if email verification is required
+                if (!user.isEmailVerified &&
+                    user.email != null &&
+                    user.providerData.any { it.providerId == "password" }
+                ) {
+                    AuthState.RequiresEmailVerification(
+                        user = user,
+                        email = user.email!!
+                    )
+                } else {
+                    AuthState.Success(result = null, user = user, isNewUser = false)
+                }
             } ?: AuthState.Idle
 
             trySend(initialState)

auth/src/main/java/com/firebase/ui/auth/compose/configuration/string_provider/AuthUIStringProvider.kt

@@ -319,4 +319,24 @@ interface AuthUIStringProvider {
 
     /** Helper text for recovery codes */
     val mfaStepShowRecoveryCodesHelper: String
+
+    // MFA Enrollment Screen Titles
+    /** Title for MFA phone number enrollment screen (top app bar) */
+    val mfaEnrollmentEnterPhoneNumber: String
+
+    /** Title for MFA SMS verification screen (top app bar) */
+    val mfaEnrollmentVerifySmsCode: String
+
+    // MFA Error Messages
+    /** Error message when MFA enrollment requires recent authentication */
+    val mfaErrorRecentLoginRequired: String
+
+    /** Error message when MFA enrollment fails due to invalid verification code */
+    val mfaErrorInvalidVerificationCode: String
+
+    /** Error message when MFA enrollment fails due to network issues */
+    val mfaErrorNetwork: String
+
+    /** Generic error message for MFA enrollment failures */
+    val mfaErrorGeneric: String
 }

auth/src/main/java/com/firebase/ui/auth/compose/configuration/string_provider/DefaultAuthUIStringProvider.kt

@@ -303,4 +303,20 @@ class DefaultAuthUIStringProvider(
         get() = localizedContext.getString(R.string.fui_mfa_step_verify_factor_generic_helper)
     override val mfaStepShowRecoveryCodesHelper: String
         get() = localizedContext.getString(R.string.fui_mfa_step_show_recovery_codes_helper)
+
+    // MFA Enrollment Screen Titles
+    override val mfaEnrollmentEnterPhoneNumber: String
+        get() = localizedContext.getString(R.string.fui_mfa_enrollment_enter_phone_number)
+    override val mfaEnrollmentVerifySmsCode: String
+        get() = localizedContext.getString(R.string.fui_mfa_enrollment_verify_sms_code)
+
+    // MFA Error Messages
+    override val mfaErrorRecentLoginRequired: String
+        get() = localizedContext.getString(R.string.fui_mfa_error_recent_login_required)
+    override val mfaErrorInvalidVerificationCode: String
+        get() = localizedContext.getString(R.string.fui_mfa_error_invalid_verification_code)
+    override val mfaErrorNetwork: String
+        get() = localizedContext.getString(R.string.fui_mfa_error_network)
+    override val mfaErrorGeneric: String
+        get() = localizedContext.getString(R.string.fui_mfa_error_generic)
 }

auth/src/main/java/com/firebase/ui/auth/compose/mfa/MfaChallengeContentState.kt

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2025 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.firebase.ui.auth.compose.mfa
+
+import com.firebase.ui.auth.compose.configuration.MfaFactor
+
+/**
+ * State class containing all the necessary information to render a custom UI for the
+ * Multi-Factor Authentication (MFA) challenge flow during sign-in.
+ *
+ * This class is passed to the content slot of the MfaChallengeScreen composable, providing
+ * access to the current factor, user input values, callbacks for actions, and loading/error states.
+ *
+ * The challenge flow is simpler than enrollment as the user has already configured their MFA:
+ * 1. User enters their verification code (SMS or TOTP)
+ * 2. System verifies the code and completes sign-in
+ *
+ * ```kotlin
+ * MfaChallengeScreen(resolver, onSuccess, onCancel, onError) { state ->
+ *     Column {
+ *         Text("Enter your ${state.factorType} code")
+ *         TextField(
+ *             value = state.verificationCode,
+ *             onValueChange = state.onVerificationCodeChange
+ *         )
+ *         if (state.canResend) {
+ *             TextButton(onClick = state.onResendCodeClick) {
+ *                 Text("Resend code")
+ *             }
+ *         }
+ *         Button(
+ *             onClick = state.onVerifyClick,
+ *             enabled = !state.isLoading && state.isValid
+ *         ) {
+ *             Text("Verify")
+ *         }
+ *     }
+ * }
+ * ```
+ *
+ * @property factorType The type of MFA factor being challenged (SMS or TOTP)
+ * @property maskedPhoneNumber For SMS factors, the masked phone number (e.g., "+1••••••890")
+ * @property isLoading `true` when verification is in progress. Use this to show loading indicators.
+ * @property error An optional error message to display to the user. Will be `null` if there's no error.
+ * @property verificationCode The current value of the verification code input field.
+ * @property resendTimer The number of seconds remaining before the "Resend" action is available. Will be 0 when resend is allowed.
+ * @property onVerificationCodeChange Callback invoked when the verification code input changes.
+ * @property onVerifyClick Callback to verify the entered code and complete sign-in.
+ * @property onResendCodeClick For SMS only: Callback to resend the verification code. `null` for TOTP.
+ * @property onCancelClick Callback to cancel the MFA challenge and return to sign-in.
+ *
+ * @since 10.0.0
+ */
+data class MfaChallengeContentState(
+    /** The type of MFA factor being challenged (SMS or TOTP). */
+    val factorType: MfaFactor,
+
+    /** For SMS: the masked phone number. For TOTP: null. */
+    val maskedPhoneNumber: String? = null,
+
+    /** `true` when verification is in progress. Use to show loading indicators. */
+    val isLoading: Boolean = false,
+
+    /** Optional error message to display. `null` if no error. */
+    val error: String? = null,
+
+    /** The current value of the verification code input field. */
+    val verificationCode: String = "",
+
+    /** The number of seconds remaining before resend is available. 0 when ready. */
+    val resendTimer: Int = 0,
+
+    /** Callback invoked when the verification code input changes. */
+    val onVerificationCodeChange: (String) -> Unit = {},
+
+    /** Callback to verify the code and complete sign-in. */
+    val onVerifyClick: () -> Unit = {},
+
+    /** For SMS only: Callback to resend the code. `null` for TOTP. */
+    val onResendCodeClick: (() -> Unit)? = null,
+
+    /** Callback to cancel the challenge and return to sign-in. */
+    val onCancelClick: () -> Unit = {}
+) {
+    /**
+     * Returns true if the current state is valid for verification.
+     * The code must be 6 digits long.
+     */
+    val isValid: Boolean
+        get() = verificationCode.length == 6 && verificationCode.all { it.isDigit() }
+
+    /**
+     * Returns true if there is an error in the current state.
+     */
+    val hasError: Boolean
+        get() = !error.isNullOrBlank()
+
+    /**
+     * Returns true if the resend action is available (SMS only).
+     */
+    val canResend: Boolean
+        get() = factorType == MfaFactor.Sms && onResendCodeClick != null
+}

auth/src/main/java/com/firebase/ui/auth/compose/mfa/MfaEnrollmentContentState.kt

@@ -16,6 +16,7 @@ package com.firebase.ui.auth.compose.mfa
 
 import com.firebase.ui.auth.compose.configuration.MfaFactor
 import com.firebase.ui.auth.compose.data.CountryData
+import com.google.firebase.auth.MultiFactorInfo
 
 /**
  * State class containing all the necessary information to render a custom UI for the
@@ -66,6 +67,7 @@ import com.firebase.ui.auth.compose.data.CountryData
  * @property onVerificationCodeChange (Step: [MfaEnrollmentStep.VerifyFactor]) Callback invoked when the verification code input changes. Receives the new code string.
  * @property onVerifyClick (Step: [MfaEnrollmentStep.VerifyFactor]) Callback to verify the entered code and finalize MFA enrollment.
  * @property selectedFactor (Step: [MfaEnrollmentStep.VerifyFactor]) The MFA factor being verified (SMS or TOTP). Use this to customize UI messages.
+ * @property resendTimer (Step: [MfaEnrollmentStep.VerifyFactor], SMS only) The number of seconds remaining before the "Resend" action is available. Will be 0 when resend is allowed.
  * @property onResendCodeClick (Step: [MfaEnrollmentStep.VerifyFactor], SMS only) Callback to resend the SMS verification code. Will be `null` for TOTP verification.
  *
  * @property recoveryCodes (Step: [MfaEnrollmentStep.ShowRecoveryCodes]) A list of one-time backup codes the user should save. Only present if [com.firebase.ui.auth.compose.configuration.MfaConfiguration.enableRecoveryCodes] is `true`.
@@ -89,8 +91,12 @@ data class MfaEnrollmentContentState(
     // SelectFactor step
     val availableFactors: List<MfaFactor> = emptyList(),
 
+    val enrolledFactors: List<MultiFactorInfo> = emptyList(),
+
     val onFactorSelected: (MfaFactor) -> Unit = {},
 
+    val onUnenrollFactor: (MultiFactorInfo) -> Unit = {},
+
     val onSkipClick: (() -> Unit)? = null,
 
     // ConfigureSms step
@@ -120,6 +126,8 @@ data class MfaEnrollmentContentState(
 
     val selectedFactor: MfaFactor? = null,
 
+    val resendTimer: Int = 0,
+
     val onResendCodeClick: (() -> Unit)? = null,
 
     // ShowRecoveryCodes step

auth/src/main/java/com/firebase/ui/auth/compose/mfa/MfaErrorMapper.kt

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2025 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the
+ * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.firebase.ui.auth.compose.mfa
+
+import com.firebase.ui.auth.compose.configuration.string_provider.AuthUIStringProvider
+import com.google.firebase.FirebaseNetworkException
+import com.google.firebase.auth.FirebaseAuthInvalidCredentialsException
+import com.google.firebase.auth.FirebaseAuthRecentLoginRequiredException
+import java.io.IOException
+
+/**
+ * Maps Firebase Auth exceptions to localized error messages for MFA enrollment.
+ *
+ * @param stringProvider Provider for localized strings
+ * @return Localized error message appropriate for the exception type
+ */
+fun Exception.toMfaErrorMessage(stringProvider: AuthUIStringProvider): String {
+    return when (this) {
+        is FirebaseAuthRecentLoginRequiredException ->
+            stringProvider.mfaErrorRecentLoginRequired
+        is FirebaseAuthInvalidCredentialsException ->
+            stringProvider.mfaErrorInvalidVerificationCode
+        is IOException, is FirebaseNetworkException ->
+            stringProvider.mfaErrorNetwork
+        else -> stringProvider.mfaErrorGeneric
+    }
+}