Make active survey reactive

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

@@ -38,8 +38,9 @@ constructor(
       return
     }
 
-    surveyRepository.activeSurvey =
-      surveyRepository.getOfflineSurvey(surveyId)
-        ?: makeSurveyAvailableOffline(surveyId) ?: error("Survey $surveyId not found in remote db")
+    surveyRepository.getOfflineSurvey(surveyId)
+      ?: makeSurveyAvailableOffline(surveyId) ?: error("Survey $surveyId not found in remote db")
+
+    surveyRepository.selectedSurveyId = surveyId
   }
 }

ground/src/main/java/com/google/android/ground/persistence/local/room/dao/SurveyDao.kt

@@ -29,4 +29,8 @@ interface SurveyDao : BaseDao<SurveyEntity> {
   @Transaction
   @Query("SELECT * FROM survey WHERE id = :id")
   suspend fun findSurveyById(id: String): SurveyEntityAndRelations?
+
+  @Transaction
+  @Query("SELECT * FROM survey WHERE id = :id")
+  fun survey(id: String): Flow<SurveyEntityAndRelations?>
 }

ground/src/main/java/com/google/android/ground/persistence/local/room/stores/RoomSurveyStore.kt

@@ -48,6 +48,8 @@ class RoomSurveyStore @Inject internal constructor() : LocalSurveyStore {
   override val surveys: Flow<List<Survey>>
     get() = surveyDao.getAll().map { surveyEntities -> surveyEntities.map { it.toModelObject() } }
 
+  override fun survey(id: String): Flow<Survey?> = surveyDao.survey(id).map { it?.toModelObject() }
+
   /**
    * Attempts to update persisted data associated with a [Survey] in the local database. If the
    * provided survey does not exist, inserts the given survey into the database.

ground/src/main/java/com/google/android/ground/persistence/local/stores/LocalSurveyStore.kt

@@ -23,6 +23,8 @@ interface LocalSurveyStore {
   /** Load surveys stored in local database. */
   val surveys: Flow<List<Survey>>
 
+  fun survey(id: String): Flow<Survey?>
+
   /** Load last active survey, if any. */
   suspend fun getSurveyById(id: String): Survey?
 

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

@@ -31,12 +31,13 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.SharedFlow
 import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.map
-import kotlinx.coroutines.flow.shareIn
+import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.withTimeoutOrNull
 import timber.log.Timber
 
@@ -57,22 +58,27 @@ constructor(
   private val networkManager: NetworkManager,
   @ApplicationScope private val externalScope: CoroutineScope
 ) {
-  private val _activeSurvey = MutableStateFlow<Survey?>(null)
+  private val _selectedSurveyIdFlow = MutableStateFlow<String?>(null)
+  var selectedSurveyId: String?
+    get() = _selectedSurveyIdFlow.value
+    set(value) {
+      _selectedSurveyIdFlow.value = value
+    }
 
-  val activeSurveyFlow: SharedFlow<Survey?> =
-    _activeSurvey.shareIn(externalScope, replay = 1, started = SharingStarted.Eagerly)
+  @OptIn(ExperimentalCoroutinesApi::class)
+  val activeSurveyFlow: StateFlow<Survey?> =
+    _selectedSurveyIdFlow
+      .flatMapLatest { id -> offlineSurvey(id) }
+      .stateIn(externalScope, SharingStarted.Lazily, null)
 
   /**
    * The currently active survey, or `null` if no survey is active. Updating this property causes
    * [lastActiveSurveyId] to be updated with the id of the specified survey, or `""` if the
    * specified survey is `null`.
    */
-  var activeSurvey: Survey?
-    get() = _activeSurvey.value
-    set(value) {
-      _activeSurvey.value = value
-      lastActiveSurveyId = value?.id ?: ""
-    }
+  var activeSurvey: Survey? = null
+    get() = activeSurveyFlow.value
+    private set
 
   val localSurveyListFlow: Flow<List<SurveyListItem>>
     get() = localSurveyStore.surveys.map { list -> list.map { it.toListItem(true) } }
@@ -89,6 +95,9 @@ constructor(
    */
   suspend fun getOfflineSurvey(surveyId: String): Survey? = localSurveyStore.getSurveyById(surveyId)
 
+  private fun offlineSurvey(id: String?): Flow<Survey?> =
+    if (id == null) flowOf(null) else localSurveyStore.survey(id)
+
   /**
    * Loads the survey with the specified id from remote and writes to local db. If the survey isn't
    * found or operation times out, then we return null and don't fetch the survey from local db.

ground/src/main/java/com/google/android/ground/ui/home/mapcontainer/HomeScreenMapContainerViewModel.kt

@@ -46,8 +46,8 @@ import kotlinx.coroutines.flow.SharedFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asSharedFlow
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.map
@@ -107,7 +107,8 @@ internal constructor(
     // TODO: Since we depend on survey stream from repo anyway, this transformation can be moved
     //  into the repository.
 
-    val activeSurvey = surveyRepository.activeSurveyFlow.distinctUntilChanged()
+    val activeSurvey = surveyRepository.activeSurveyFlow
+    viewModelScope.launch { activeSurvey.collect { Timber.e("Updated survey: $it") } }
 
     mapLoiFeatures =
       activeSurvey.flatMapLatest {
@@ -126,7 +127,9 @@ internal constructor(
           else loiRepository.getWithinBounds(survey, bounds)
         }
         .stateIn(viewModelScope, SharingStarted.Lazily, listOf())
-
+    viewModelScope.launch {
+      loisInViewport.collect { Timber.e("Updated loisInViewport: ${it.firstOrNull()}") }
+    }
     adHocLoiJobs =
       activeSurvey
         .combine(isZoomedInFlow) { survey, isZoomedIn -> Pair(survey, isZoomedIn) }
@@ -136,6 +139,9 @@ internal constructor(
             else survey.jobs.filter { it.canDataCollectorsAddLois }
           )
         }
+    viewModelScope.launch {
+      adHocLoiJobs.collect { Timber.e("Updated adHocLoiJobs: $adHocLoiJobs") }
+    }
   }
 
   override fun onMapCameraMoved(newCameraPosition: CameraPosition) {