feat: MFA Config Model (MfaConfiguration, MfaFactor)

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

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+/*
+ * 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.configuration
+
+/**
+ * Configuration class for Multi-Factor Authentication (MFA) enrollment and verification behavior.
+ *
+ * This class controls which MFA factors are available to users, whether enrollment is mandatory,
+ * and whether recovery codes are generated.
+ *
+ * @property allowedFactors List of MFA factors that users are permitted to enroll in.
+ *                          Defaults to [MfaFactor.Sms, MfaFactor.Totp].
+ * @property requireEnrollment Whether MFA enrollment is mandatory for all users.
+ *                             When true, users must enroll in at least one MFA factor.
+ *                             Defaults to false.
+ * @property enableRecoveryCodes Whether to generate and provide recovery codes to users
+ *                               after successful MFA enrollment. These codes can be used
+ *                               as a backup authentication method. Defaults to true.
+ */
+class MfaConfiguration(
+    val allowedFactors: List<MfaFactor> = listOf(MfaFactor.Sms, MfaFactor.Totp),
+    val requireEnrollment: Boolean = false,
+    val enableRecoveryCodes: Boolean = true
+) {
+    init {
+        require(allowedFactors.isNotEmpty()) {
+            "At least one MFA factor must be allowed"
+        }
+    }
+}

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

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+/*
+ * 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.configuration
+
+/**
+ * Represents the different Multi-Factor Authentication (MFA) factors that can be used
+ * for enrollment and verification.
+ */
+enum class MfaFactor {
+    /**
+     * SMS-based authentication factor.
+     * Users receive a verification code via text message to their registered phone number.
+     */
+    Sms,
+
+    /**
+     * Time-based One-Time Password (TOTP) authentication factor.
+     * Users generate verification codes using an authenticator app.
+     */
+    Totp
+}

auth/src/test/java/com/firebase/ui/auth/compose/configuration/MfaConfigurationTest.kt

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+/*
+ * 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.configuration
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+/**
+ * Unit tests for [MfaConfiguration] covering default values, custom configurations,
+ * and validation rules.
+ *
+ * @suppress Internal test class
+ */
+@RunWith(RobolectricTestRunner::class)
+@Config(manifest = Config.NONE)
+class MfaConfigurationTest {
+
+    // =============================================================================================
+    // Default Configuration Tests
+    // =============================================================================================
+
+    @Test
+    fun `MfaConfiguration with defaults uses correct values`() {
+        val config = MfaConfiguration()
+
+        assertThat(config.allowedFactors).containsExactly(MfaFactor.Sms, MfaFactor.Totp)
+        assertThat(config.requireEnrollment).isFalse()
+        assertThat(config.enableRecoveryCodes).isTrue()
+    }
+
+    @Test
+    fun `MfaConfiguration default allowedFactors includes both Sms and Totp`() {
+        val config = MfaConfiguration()
+
+        assertThat(config.allowedFactors).hasSize(2)
+        assertThat(config.allowedFactors).contains(MfaFactor.Sms)
+        assertThat(config.allowedFactors).contains(MfaFactor.Totp)
+    }
+
+    // =============================================================================================
+    // Custom Configuration Tests
+    // =============================================================================================
+
+    @Test
+    fun `MfaConfiguration with custom allowedFactors only Sms`() {
+        val config = MfaConfiguration(
+            allowedFactors = listOf(MfaFactor.Sms)
+        )
+
+        assertThat(config.allowedFactors).containsExactly(MfaFactor.Sms)
+        assertThat(config.allowedFactors).hasSize(1)
+    }
+
+    @Test
+    fun `MfaConfiguration with custom allowedFactors only Totp`() {
+        val config = MfaConfiguration(
+            allowedFactors = listOf(MfaFactor.Totp)
+        )
+
+        assertThat(config.allowedFactors).containsExactly(MfaFactor.Totp)
+        assertThat(config.allowedFactors).hasSize(1)
+    }
+
+    @Test
+    fun `MfaConfiguration with requireEnrollment enabled`() {
+        val config = MfaConfiguration(
+            requireEnrollment = true
+        )
+
+        assertThat(config.requireEnrollment).isTrue()
+    }
+
+    @Test
+    fun `MfaConfiguration with enableRecoveryCodes disabled`() {
+        val config = MfaConfiguration(
+            enableRecoveryCodes = false
+        )
+
+        assertThat(config.enableRecoveryCodes).isFalse()
+    }
+
+    @Test
+    fun `MfaConfiguration with all custom values`() {
+        val config = MfaConfiguration(
+            allowedFactors = listOf(MfaFactor.Sms),
+            requireEnrollment = true,
+            enableRecoveryCodes = false
+        )
+
+        assertThat(config.allowedFactors).containsExactly(MfaFactor.Sms)
+        assertThat(config.requireEnrollment).isTrue()
+        assertThat(config.enableRecoveryCodes).isFalse()
+    }
+
+    // =============================================================================================
+    // Validation Tests
+    // =============================================================================================
+
+    @Test
+    fun `MfaConfiguration throws when allowedFactors is empty`() {
+        try {
+            MfaConfiguration(
+                allowedFactors = emptyList()
+            )
+        } catch (e: Exception) {
+            assertThat(e).isInstanceOf(IllegalArgumentException::class.java)
+            assertThat(e.message).isEqualTo("At least one MFA factor must be allowed")
+        }
+    }
+
+    @Test
+    fun `MfaConfiguration allows both factors in any order`() {
+        val config1 = MfaConfiguration(
+            allowedFactors = listOf(MfaFactor.Sms, MfaFactor.Totp)
+        )
+        val config2 = MfaConfiguration(
+            allowedFactors = listOf(MfaFactor.Totp, MfaFactor.Sms)
+        )
+
+        assertThat(config1.allowedFactors).hasSize(2)
+        assertThat(config2.allowedFactors).hasSize(2)
+        assertThat(config1.allowedFactors).containsExactly(MfaFactor.Sms, MfaFactor.Totp)
+        assertThat(config2.allowedFactors).containsExactly(MfaFactor.Totp, MfaFactor.Sms)
+    }
+
+    // =============================================================================================
+    // MfaFactor Enum Tests
+    // =============================================================================================
+
+    @Test
+    fun `MfaFactor enum has exactly two values`() {
+        val factors = MfaFactor.entries
+
+        assertThat(factors).hasSize(2)
+        assertThat(factors).containsExactly(MfaFactor.Sms, MfaFactor.Totp)
+    }
+
+    @Test
+    fun `MfaFactor Sms has correct name`() {
+        assertThat(MfaFactor.Sms.name).isEqualTo("Sms")
+    }
+
+    @Test
+    fun `MfaFactor Totp has correct name`() {
+        assertThat(MfaFactor.Totp.name).isEqualTo("Totp")
+    }
+}