[Code health] Migrate remaining business logic from SurveyRepository to a domain use case

app/src/main/java/com/google/android/ground/MainViewModel.kt

@@ -99,7 +99,6 @@ constructor(
   private fun onUserSignedOut(): MainUiState {
     // Scope of subscription is until view model is cleared. Dispose it manually otherwise, firebase
     // attempts to maintain a connection even after user has logged out and throws an error.
-    userRepository.clearUserPreferences()
 
     // TODO: Once multi-user login is supported, avoid clearing local db data. This is
     //  currently being done to prevent one user's data to be submitted as another user after
@@ -108,6 +107,7 @@ constructor(
     viewModelScope.launch {
       withContext(ioDispatcher) {
         surveyRepository.clearActiveSurvey()
+        userRepository.clearUserPreferences()
         localDatabase.clearAllTables()
       }
     }

app/src/main/java/com/google/android/ground/domain/usecases/survey/ReactivateLastSurveyUseCase.kt

@@ -29,14 +29,16 @@ constructor(
   private val surveyRepository: SurveyRepository,
 ) {
 
-  suspend operator fun invoke(): Boolean =
-    if (getLastActiveSurveyId().isEmpty()) {
-      false
-    } else if (surveyRepository.hasActiveSurvey()) {
-      true
-    } else {
-      activateSurvey(getLastActiveSurveyId())
+  suspend operator fun invoke(): Boolean {
+    if (surveyRepository.activeSurvey != null) {
+      // Skip if there is an active survey.
+      return true
     }
-
-  private fun getLastActiveSurveyId(): String = localValueStore.lastActiveSurveyId
+    val lastActiveSurveyId = localValueStore.lastActiveSurveyId
+    if (lastActiveSurveyId.isEmpty()) {
+      // Nothing to be re-activated.
+      return false
+    }
+    return activateSurvey(lastActiveSurveyId)
+  }
 }

app/src/main/java/com/google/android/ground/domain/usecases/survey/RemoveOfflineSurveyUseCase.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * 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
+ *
+ *     https://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.google.android.ground.domain.usecases.survey
+
+import com.google.android.ground.persistence.local.stores.LocalSurveyStore
+import com.google.android.ground.repository.SurveyRepository
+import javax.inject.Inject
+
+class RemoveOfflineSurveyUseCase
+@Inject
+constructor(
+  private val localSurveyStore: LocalSurveyStore,
+  private val surveyRepository: SurveyRepository,
+) {
+
+  /**
+   * Attempts to remove the locally synced survey. Also, deactivates it before removing, if it is
+   * active. Doesn't throw an error if it doesn't exist.
+   */
+  suspend operator fun invoke(surveyId: String) {
+    if (surveyRepository.isSurveyActive(surveyId)) {
+      surveyRepository.clearActiveSurvey()
+    }
+
+    val survey = localSurveyStore.getSurveyById(surveyId) ?: return
+    localSurveyStore.deleteSurvey(survey)
+  }
+}

app/src/main/java/com/google/android/ground/repository/SurveyRepository.kt

@@ -28,23 +28,16 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flowOf
-import kotlinx.coroutines.flow.launchIn
-import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.withTimeout
 
 private const val ACTIVATE_SURVEY_TIMEOUT_MILLS: Long = 3 * 1000
 
-/**
- * Coordinates persistence and retrieval of [Survey] instances from remote, local, and in memory
- * data stores. For more details on this pattern and overall architecture, see
- * https://developer.android.com/jetpack/docs/guide.
- */
+/** Maintains the state of currently active survey. */
 @OptIn(ExperimentalCoroutinesApi::class)
 @Singleton
 class SurveyRepository
@@ -66,13 +59,6 @@ constructor(
   val activeSurvey: Survey?
     get() = activeSurveyFlow.value
 
-  /** The id of the last activated survey. */
-  private var lastActiveSurveyId: String by localValueStore::lastActiveSurveyId
-
-  init {
-    activeSurveyFlow.filterNotNull().onEach { lastActiveSurveyId = it.id }.launchIn(externalScope)
-  }
-
   /**
    * Returns the survey with the specified id from the local db, or `null` if not available offline.
    */
@@ -99,24 +85,16 @@ constructor(
       }
     }
 
-    firebaseCrashLogger.setSelectedSurveyId(surveyId)
+    if (isSurveyActive(surveyId) || surveyId.isBlank()) {
+      firebaseCrashLogger.setSelectedSurveyId(surveyId)
+      localValueStore.lastActiveSurveyId = surveyId
+    }
   }
 
   suspend fun clearActiveSurvey() {
     activateSurvey("")
   }
 
-  fun hasActiveSurvey(): Boolean = activeSurvey != null
-
   fun isSurveyActive(surveyId: String): Boolean =
     surveyId.isNotBlank() && activeSurvey?.id == surveyId
-
-  /** Attempts to remove the locally synced survey. Doesn't throw an error if it doesn't exist. */
-  suspend fun removeOfflineSurvey(surveyId: String) {
-    val survey = localSurveyStore.getSurveyById(surveyId) ?: return
-    localSurveyStore.deleteSurvey(survey)
-    if (isSurveyActive(surveyId)) {
-      clearActiveSurvey()
-    }
-  }
 }

app/src/main/java/com/google/android/ground/ui/surveyselector/SurveySelectorViewModel.kt

@@ -20,8 +20,8 @@ import com.google.android.ground.coroutines.ApplicationScope
 import com.google.android.ground.coroutines.IoDispatcher
 import com.google.android.ground.domain.usecases.survey.ActivateSurveyUseCase
 import com.google.android.ground.domain.usecases.survey.ListAvailableSurveysUseCase
+import com.google.android.ground.domain.usecases.survey.RemoveOfflineSurveyUseCase
 import com.google.android.ground.model.SurveyListItem
-import com.google.android.ground.repository.SurveyRepository
 import com.google.android.ground.repository.UserRepository
 import com.google.android.ground.ui.common.AbstractViewModel
 import javax.inject.Inject
@@ -40,11 +40,11 @@ import timber.log.Timber
 class SurveySelectorViewModel
 @Inject
 internal constructor(
-  private val surveyRepository: SurveyRepository,
   private val activateSurveyUseCase: ActivateSurveyUseCase,
   @ApplicationScope private val externalScope: CoroutineScope,
   @IoDispatcher private val ioDispatcher: CoroutineDispatcher,
   private val listAvailableSurveysUseCase: ListAvailableSurveysUseCase,
+  private val remoteOfflineSurveyUseCase: RemoveOfflineSurveyUseCase,
   private val userRepository: UserRepository,
 ) : AbstractViewModel() {
 
@@ -108,7 +108,7 @@ internal constructor(
   }
 
   fun deleteSurvey(surveyId: String) {
-    externalScope.launch(ioDispatcher) { surveyRepository.removeOfflineSurvey(surveyId) }
+    externalScope.launch(ioDispatcher) { remoteOfflineSurveyUseCase(surveyId) }
   }
 
   fun signOut() {

app/src/test/java/com/google/android/ground/domain/usecases/survey/RemoveOfflineSurveyUseCaseTest.kt

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * 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
+ *
+ *     https://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.google.android.ground.domain.usecases.survey
+
+import app.cash.turbine.test
+import com.google.android.ground.BaseHiltTest
+import com.google.android.ground.FakeData.SURVEY
+import com.google.android.ground.persistence.local.stores.LocalSurveyStore
+import com.google.android.ground.repository.SurveyRepository
+import com.google.common.truth.Truth.assertThat
+import dagger.hilt.android.testing.HiltAndroidTest
+import javax.inject.Inject
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.advanceUntilIdle
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+
+@OptIn(ExperimentalCoroutinesApi::class)
+@HiltAndroidTest
+@RunWith(RobolectricTestRunner::class)
+class RemoveOfflineSurveyUseCaseTest : BaseHiltTest() {
+  @Inject lateinit var activateSurvey: ActivateSurveyUseCase
+  @Inject lateinit var localSurveyStore: LocalSurveyStore
+  @Inject lateinit var removeOfflineSurveyUseCase: RemoveOfflineSurveyUseCase
+  @Inject lateinit var surveyRepository: SurveyRepository
+
+  @Test
+  fun `should delete local copy`() = runWithTestDispatcher {
+    localSurveyStore.insertOrUpdateSurvey(SURVEY)
+
+    removeOfflineSurveyUseCase(SURVEY.id)
+
+    localSurveyStore.surveys.test { assertThat(expectMostRecentItem()).isEmpty() }
+  }
+
+  @Test
+  fun `should not throw if local copy missing`() = runWithTestDispatcher {
+    removeOfflineSurveyUseCase(SURVEY.id)
+
+    localSurveyStore.surveys.test { assertThat(expectMostRecentItem()).isEmpty() }
+  }
+
+  @Test
+  fun `when active survey is same, should deactivate as well`() = runWithTestDispatcher {
+    localSurveyStore.insertOrUpdateSurvey(SURVEY)
+    activateSurvey(SURVEY.id)
+
+    removeOfflineSurveyUseCase(SURVEY.id)
+
+    assertThat(surveyRepository.activeSurvey).isNull()
+  }
+
+  @Test
+  fun `when active survey is different, should not deactivate`() = runWithTestDispatcher {
+    val survey1 = SURVEY.copy(id = "active survey id", jobMap = emptyMap())
+    val survey2 = SURVEY.copy(id = "inactive survey id", jobMap = emptyMap())
+    localSurveyStore.insertOrUpdateSurvey(survey1)
+    localSurveyStore.insertOrUpdateSurvey(survey2)
+    activateSurvey(survey1.id)
+    advanceUntilIdle()
+
+    removeOfflineSurveyUseCase(survey2.id)
+    advanceUntilIdle()
+
+    // Verify that active survey isn't cleared or de-activated
+    assertThat(surveyRepository.activeSurvey).isEqualTo(survey1)
+    localSurveyStore.surveys.test { assertThat(expectMostRecentItem()).isEqualTo(listOf(survey1)) }
+  }
+}

app/src/test/java/com/google/android/ground/repository/SurveyRepositoryTest.kt

@@ -64,44 +64,4 @@ class SurveyRepositoryTest : BaseHiltTest() {
     surveyRepository.activeSurveyFlow.test { assertThat(expectMostRecentItem()).isNull() }
     assertThat(surveyRepository.activeSurvey).isNull()
   }
-
-  @Test
-  fun `removeOfflineSurvey - should delete local copy`() = runWithTestDispatcher {
-    localSurveyStore.insertOrUpdateSurvey(SURVEY)
-
-    surveyRepository.removeOfflineSurvey(SURVEY.id)
-
-    localSurveyStore.surveys.test { assertThat(expectMostRecentItem()).isEmpty() }
-  }
-
-  @Test
-  fun `removeOfflineSurvey - when active survey is same, should deactivate as well`() =
-    runWithTestDispatcher {
-      localSurveyStore.insertOrUpdateSurvey(SURVEY)
-      activateSurvey(SURVEY.id)
-
-      surveyRepository.removeOfflineSurvey(SURVEY.id)
-
-      assertThat(surveyRepository.activeSurvey).isNull()
-    }
-
-  @Test
-  fun `removeOfflineSurvey - when active survey is different, should not deactivate`() =
-    runWithTestDispatcher {
-      val survey1 = SURVEY.copy(id = "active survey id", jobMap = emptyMap())
-      val survey2 = SURVEY.copy(id = "inactive survey id", jobMap = emptyMap())
-      localSurveyStore.insertOrUpdateSurvey(survey1)
-      localSurveyStore.insertOrUpdateSurvey(survey2)
-      activateSurvey(survey1.id)
-      advanceUntilIdle()
-
-      surveyRepository.removeOfflineSurvey(survey2.id)
-      advanceUntilIdle()
-
-      // Verify that active survey isn't cleared or de-activated
-      assertThat(surveyRepository.activeSurvey).isEqualTo(survey1)
-      localSurveyStore.surveys.test {
-        assertThat(expectMostRecentItem()).isEqualTo(listOf(survey1))
-      }
-    }
 }

app/src/test/java/com/google/android/ground/ui/surveyselector/SurveySelectorFragmentTest.kt

@@ -43,6 +43,7 @@ import com.google.android.ground.FakeData
 import com.google.android.ground.R
 import com.google.android.ground.domain.usecases.survey.ActivateSurveyUseCase
 import com.google.android.ground.domain.usecases.survey.ListAvailableSurveysUseCase
+import com.google.android.ground.domain.usecases.survey.RemoveOfflineSurveyUseCase
 import com.google.android.ground.launchFragmentInHiltContainer
 import com.google.android.ground.launchFragmentWithNavController
 import com.google.android.ground.model.SurveyListItem
@@ -81,6 +82,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
   @BindValue @Mock lateinit var userRepository: UserRepository
   @BindValue @Mock lateinit var activateSurvey: ActivateSurveyUseCase
   @BindValue @Mock lateinit var listAvailableSurveysUseCase: ListAvailableSurveysUseCase
+  @BindValue @Mock lateinit var removeOfflineSurveyUseCase: RemoveOfflineSurveyUseCase
   @Inject lateinit var fakeAuthenticationManager: FakeAuthenticationManager
 
   private lateinit var fragment: SurveySelectorFragment
@@ -257,7 +259,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
     advanceUntilIdle()
 
     // Assert survey is deleted
-    verify(surveyRepository).removeOfflineSurvey(TEST_SURVEY_2.id)
+    verify(removeOfflineSurveyUseCase).invoke(TEST_SURVEY_2.id)
   }
 
   @Test