[BWA-58] Define feature flag repo (#176)

app/src/main/kotlin/com/bitwarden/authenticator/data/platform/repository/FeatureFlagRepository.kt

@@ -0,0 +1,20 @@
+package com.bitwarden.authenticator.data.platform.repository
+
+import com.bitwarden.authenticator.data.platform.datasource.disk.model.FeatureFlagsConfiguration
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * Provides an API for observing the server config state.
+ */
+interface FeatureFlagRepository {
+
+    /**
+     * Emits updates that track [FeatureFlagsConfiguration].
+     */
+    val featureFlagConfigStateFlow: StateFlow<FeatureFlagsConfiguration?>
+
+    /**
+     * Gets the state [FeatureFlagsConfiguration].
+     */
+    suspend fun getFeatureFlagsConfiguration(): FeatureFlagsConfiguration
+}

app/src/main/kotlin/com/bitwarden/authenticator/data/platform/repository/FeatureFlagRepositoryImpl.kt

@@ -0,0 +1,47 @@
+package com.bitwarden.authenticator.data.platform.repository
+
+import com.bitwarden.authenticator.data.platform.datasource.disk.FeatureFlagDiskSource
+import com.bitwarden.authenticator.data.platform.datasource.disk.model.FeatureFlagsConfiguration
+import com.bitwarden.authenticator.data.platform.manager.DispatcherManager
+import com.bitwarden.authenticator.data.platform.manager.model.LocalFeatureFlag
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.serialization.json.JsonPrimitive
+
+/**
+ * Primary implementation of [FeatureFlagRepositoryImpl].
+ */
+class FeatureFlagRepositoryImpl(
+    private val featureFlagDiskSource: FeatureFlagDiskSource,
+    dispatcherManager: DispatcherManager,
+) : FeatureFlagRepository {
+
+    private val unconfinedScope = CoroutineScope(dispatcherManager.unconfined)
+
+    override val featureFlagConfigStateFlow: StateFlow<FeatureFlagsConfiguration?>
+        get() = featureFlagDiskSource
+            .featureFlagsConfigurationFlow
+            .stateIn(
+                scope = unconfinedScope,
+                started = SharingStarted.Eagerly,
+                initialValue = featureFlagDiskSource.featureFlagsConfiguration,
+            )
+
+    override suspend fun getFeatureFlagsConfiguration() =
+        featureFlagDiskSource.featureFlagsConfiguration
+            ?: initLocalFeatureFlagsConfiguration()
+
+    private fun initLocalFeatureFlagsConfiguration(): FeatureFlagsConfiguration {
+        val config = FeatureFlagsConfiguration(
+            mapOf(
+                LocalFeatureFlag.BitwardenAuthenticationEnabled.name to JsonPrimitive(
+                    LocalFeatureFlag.BitwardenAuthenticationEnabled.defaultValue
+                )
+            )
+        )
+        featureFlagDiskSource.featureFlagsConfiguration = config
+        return config
+    }
+}

app/src/main/kotlin/com/bitwarden/authenticator/data/platform/repository/di/PlatformRepositoryModule.kt

@@ -2,9 +2,12 @@ package com.bitwarden.authenticator.data.platform.repository.di
 
 import com.bitwarden.authenticator.data.auth.datasource.disk.AuthDiskSource
 import com.bitwarden.authenticator.data.authenticator.datasource.sdk.AuthenticatorSdkSource
+import com.bitwarden.authenticator.data.platform.datasource.disk.FeatureFlagDiskSource
 import com.bitwarden.authenticator.data.platform.datasource.disk.SettingsDiskSource
 import com.bitwarden.authenticator.data.platform.manager.BiometricsEncryptionManager
 import com.bitwarden.authenticator.data.platform.manager.DispatcherManager
+import com.bitwarden.authenticator.data.platform.repository.FeatureFlagRepository
+import com.bitwarden.authenticator.data.platform.repository.FeatureFlagRepositoryImpl
 import com.bitwarden.authenticator.data.platform.repository.SettingsRepository
 import com.bitwarden.authenticator.data.platform.repository.SettingsRepositoryImpl
 import dagger.Module
@@ -36,4 +39,15 @@ object PlatformRepositoryModule {
             biometricsEncryptionManager = biometricsEncryptionManager,
             authenticatorSdkSource = authenticatorSdkSource,
         )
+
+    @Provides
+    @Singleton
+    fun provideFeatureFlagRepo(
+        featureFlagDiskSource: FeatureFlagDiskSource,
+        dispatcherManager: DispatcherManager,
+    ): FeatureFlagRepository =
+        FeatureFlagRepositoryImpl(
+            featureFlagDiskSource = featureFlagDiskSource,
+            dispatcherManager = dispatcherManager,
+        )
 }

app/src/test/java/com/bitwarden/authenticator/data/platform/base/FakeDispatcherManager.kt

@@ -0,0 +1,37 @@
+package com.bitwarden.authenticator.data.platform.base
+
+import com.bitwarden.authenticator.data.platform.manager.DispatcherManager
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.MainCoroutineDispatcher
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.setMain
+
+/**
+ * A faked implementation of [DispatcherManager] that uses [UnconfinedTestDispatcher].
+ */
+@OptIn(ExperimentalCoroutinesApi::class)
+class FakeDispatcherManager(
+    override val default: CoroutineDispatcher = UnconfinedTestDispatcher(),
+    override val io: CoroutineDispatcher = UnconfinedTestDispatcher(),
+    override val unconfined: CoroutineDispatcher = UnconfinedTestDispatcher(),
+) : DispatcherManager {
+    override val main: MainCoroutineDispatcher = Dispatchers.Main
+
+    /**
+     * Updates the main dispatcher to use the provided [dispatcher]. Used in conjunction with
+     * [resetMain].
+     */
+    fun setMain(dispatcher: CoroutineDispatcher) {
+        Dispatchers.setMain(dispatcher)
+    }
+
+    /**
+     * Restores the main dispatcher to it's default state. Used in conjunction with [setMain].
+     */
+    fun resetMain() {
+        Dispatchers.resetMain()
+    }
+}

app/src/test/java/com/bitwarden/authenticator/data/platform/datasource/disk/util/FakeFeatureFlagDiskSource.kt

@@ -0,0 +1,27 @@
+package com.bitwarden.authenticator.data.platform.datasource.disk.util
+
+import com.bitwarden.authenticator.data.platform.datasource.disk.FeatureFlagDiskSource
+import com.bitwarden.authenticator.data.platform.datasource.disk.model.FeatureFlagsConfiguration
+import com.bitwarden.authenticator.data.platform.repository.util.bufferedMutableSharedFlow
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.onSubscription
+
+/**
+ * A faked implementation of [FeatureFlagDiskSource] for testing.
+ */
+class FakeFeatureFlagDiskSource : FeatureFlagDiskSource {
+
+    private var configuration: FeatureFlagsConfiguration? = null
+    private val mutableConfigurationFlow =
+        bufferedMutableSharedFlow<FeatureFlagsConfiguration?>(replay = 1)
+
+    override var featureFlagsConfiguration: FeatureFlagsConfiguration?
+        get() = configuration
+        set(value) {
+            configuration = value
+            mutableConfigurationFlow.tryEmit(value)
+        }
+    override val featureFlagsConfigurationFlow: Flow<FeatureFlagsConfiguration?>
+        get() = mutableConfigurationFlow
+            .onSubscription { emit(configuration) }
+}

app/src/test/java/com/bitwarden/authenticator/data/platform/repository/FeatureFlagRepositoryTest.kt

@@ -0,0 +1,53 @@
+package com.bitwarden.authenticator.data.platform.repository
+
+import app.cash.turbine.test
+import com.bitwarden.authenticator.data.platform.base.FakeDispatcherManager
+import com.bitwarden.authenticator.data.platform.datasource.disk.model.FeatureFlagsConfiguration
+import com.bitwarden.authenticator.data.platform.datasource.disk.util.FakeFeatureFlagDiskSource
+import com.bitwarden.authenticator.data.platform.manager.model.LocalFeatureFlag
+import kotlinx.coroutines.test.runTest
+import kotlinx.serialization.json.JsonPrimitive
+import org.junit.Test
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertNull
+
+class FeatureFlagRepositoryTest {
+
+    private val fakeFeatureFlagDiskSource = FakeFeatureFlagDiskSource()
+    private val featureFlagRepo = FeatureFlagRepositoryImpl(
+        featureFlagDiskSource = fakeFeatureFlagDiskSource,
+        dispatcherManager = FakeDispatcherManager(),
+    )
+
+    @Suppress("MaxLineLength")
+    @Test
+    fun `getFeatureFlagsConfiguration should init configuration with local flags when there is none in state`() =
+        runTest {
+            assertNull(fakeFeatureFlagDiskSource.featureFlagsConfiguration)
+
+            featureFlagRepo.getFeatureFlagsConfiguration()
+
+            assertEquals(
+                FEATURE_FLAGS_CONFIG,
+                fakeFeatureFlagDiskSource.featureFlagsConfiguration
+            )
+        }
+
+    @Test
+    fun `featureFlagsConfigurationFlow should react to feature flag configuration changes`() =
+        runTest {
+            featureFlagRepo.getFeatureFlagsConfiguration()
+
+            featureFlagRepo.featureFlagConfigStateFlow.test {
+                assertEquals(fakeFeatureFlagDiskSource.featureFlagsConfiguration, awaitItem())
+            }
+        }
+}
+
+private val FEATURE_FLAGS_CONFIG =
+    FeatureFlagsConfiguration(
+        featureFlags = mapOf(
+            LocalFeatureFlag.BitwardenAuthenticationEnabled.name to
+                JsonPrimitive(LocalFeatureFlag.BitwardenAuthenticationEnabled.defaultValue),
+        )
+    )