Draft remote / local survey list

ground/src/main/java/com/google/android/ground/persistence/remote/RemoteDataStore.kt

@@ -21,13 +21,15 @@ import com.google.android.ground.model.User
 import com.google.android.ground.model.locationofinterest.LocationOfInterest
 import com.google.android.ground.model.mutation.Mutation
 import com.google.android.ground.model.submission.Submission
+import kotlinx.coroutines.flow.Flow
 
 /**
  * Defines API for accessing data in a remote data store. Implementations must ensure all
  * subscriptions are run in a background thread (i.e., not the Android main thread).
  */
 interface RemoteDataStore {
-  suspend fun loadSurveySummaries(user: User): List<Survey>
+  // TODO: Refactor SurveyItem into model class SurveyListItem and return from here.
+  fun getSurveyList(user: User): Flow<List<Survey>>
 
   /**
    * Loads the survey with the specified id from the remote data store. Returns `null` if the survey

ground/src/main/java/com/google/android/ground/persistence/remote/firebase/FirestoreDataStore.kt

@@ -32,6 +32,9 @@ import com.google.firebase.messaging.ktx.messaging
 import javax.inject.Inject
 import javax.inject.Singleton
 import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.emitAll
+import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.tasks.await
 import kotlinx.coroutines.withContext
 import timber.log.Timber
@@ -64,8 +67,9 @@ internal constructor(
   override suspend fun loadTermsOfService(): TermsOfService? =
     withContext(ioDispatcher) { db().termsOfService().terms().get() }
 
-  override suspend fun loadSurveySummaries(user: User): List<Survey> =
-    withContext(ioDispatcher) { db().surveys().getReadable(user) }
+  override fun getSurveyList(user: User): Flow<List<Survey>> = flow {
+    emitAll(db().surveys().getReadable(user))
+  }
 
   override suspend fun loadLocationsOfInterest(survey: Survey) =
     db().surveys().survey(survey.id).lois().locationsOfInterest(survey)

ground/src/main/java/com/google/android/ground/persistence/remote/firebase/schema/SurveysCollectionReference.kt

@@ -21,8 +21,10 @@ import com.google.android.ground.model.Survey
 import com.google.android.ground.model.User
 import com.google.android.ground.persistence.remote.firebase.base.FluentCollectionReference
 import com.google.firebase.firestore.CollectionReference
-import com.google.firebase.firestore.DocumentSnapshot
 import com.google.firebase.firestore.FieldPath
+import com.google.firebase.firestore.snapshots
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
 
 private const val ACL_FIELD = "acl"
 
@@ -31,9 +33,8 @@ class SurveysCollectionReference internal constructor(ref: CollectionReference)
 
   fun survey(id: String) = SurveyDocumentReference(reference().document(id))
 
-  suspend fun getReadable(user: User): List<Survey> =
-    runQuery(reference().whereIn(FieldPath.of(ACL_FIELD, user.email), Role.valueStrings())) {
-      doc: DocumentSnapshot ->
-      SurveyConverter.toSurvey(doc)
+  fun getReadable(user: User): Flow<List<Survey>> =
+    reference().whereIn(FieldPath.of(ACL_FIELD, user.email), Role.valueStrings()).snapshots().map {
+      it.documents.map { doc -> SurveyConverter.toSurvey(doc) }
     }
 }

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

@@ -22,25 +22,27 @@ import com.google.android.ground.persistence.local.LocalValueStore
 import com.google.android.ground.persistence.local.stores.LocalSurveyStore
 import com.google.android.ground.persistence.remote.RemoteDataStore
 import com.google.android.ground.rx.annotations.Cold
+import com.google.android.ground.system.NetworkManager
+import com.google.android.ground.system.NetworkStatus
 import io.reactivex.Flowable
 import java8.util.Optional
 import javax.inject.Inject
 import javax.inject.Singleton
 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.asFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.shareIn
 import kotlinx.coroutines.rx2.asFlowable
-import kotlinx.coroutines.withTimeout
 import kotlinx.coroutines.withTimeoutOrNull
 import timber.log.Timber
 
 private const val LOAD_REMOTE_SURVEY_TIMEOUT_MILLS: Long = 15 * 1000
-private const val LOAD_REMOTE_SURVEY_SUMMARIES_TIMEOUT_MILLIS: Long = 30 * 1000
 
 /**
  * Coordinates persistence and retrieval of [Survey] instances from remote, local, and in memory
@@ -54,6 +56,7 @@ constructor(
   private val localSurveyStore: LocalSurveyStore,
   private val remoteDataStore: RemoteDataStore,
   private val localValueStore: LocalValueStore,
+  private val networkManager: NetworkManager,
   @ApplicationScope private val externalScope: CoroutineScope
 ) {
   private val _activeSurvey = MutableStateFlow<Survey?>(null)
@@ -82,7 +85,7 @@ constructor(
   val activeSurveyFlowable: @Cold Flowable<Optional<Survey>> =
     activeSurveyFlow.map { if (it == null) Optional.empty() else Optional.of(it) }.asFlowable()
 
-  val offlineSurveys: Flow<List<Survey>>
+  val localSurveysFlow: Flow<List<Survey>>
     get() = localSurveyStore.surveys
 
   var lastActiveSurveyId: String by localValueStore::lastActiveSurveyId
@@ -114,20 +117,27 @@ constructor(
   fun clearActiveSurvey() {
     activeSurvey = null
   }
+  //  offlineSurveys.any { it.id == survey.id }
+  fun getSurveyList(user: User): Flow<List<Pair<Survey, Boolean>>> =
+    @OptIn(ExperimentalCoroutinesApi::class)
+    networkManager.networkStatusFlow.flatMapLatest { networkStatus ->
+      if (networkStatus == NetworkStatus.AVAILABLE) {
+        getRemoteSurveyList(user)
+      } else {
+        getLocalSurveyList(user)
+      }
+    }
 
-  suspend fun getSurveySummaries(user: User): Flow<List<Survey>> =
-    try {
-      val surveys =
-        withTimeout(LOAD_REMOTE_SURVEY_SUMMARIES_TIMEOUT_MILLIS) {
-          Timber.d("Loading survey list from remote")
-          remoteDataStore.loadSurveySummaries(user)
-        }
-      listOf(surveys).asFlow()
-    } catch (e: Throwable) {
-      Timber.d(e, "Failed to load survey list from remote")
-      offlineSurveys
+  private fun getRemoteSurveyList(user: User): Flow<List<Pair<Survey, Boolean>>> =
+    remoteDataStore.getSurveyList(user).combine(localSurveysFlow) { remoteSurveys, localSurveys ->
+      remoteSurveys.map { remoteSurvey ->
+        Pair(remoteSurvey, localSurveys.any { it.id == remoteSurvey.id })
+      }
     }
 
+  private fun getLocalSurveyList(user: User): Flow<List<Pair<Survey, Boolean>>> =
+    localSurveysFlow.map { localSurveys -> localSurveys.map { survey -> Pair(survey, true) } }
+
   /** 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.getSurveyByIdSuspend(surveyId)

ground/src/main/java/com/google/android/ground/system/NetworkManager.kt

@@ -17,15 +17,49 @@ package com.google.android.ground.system
 
 import android.content.Context
 import android.net.ConnectivityManager
+import android.net.Network
+import android.net.NetworkCapabilities.NET_CAPABILITY_INTERNET
+import android.net.NetworkRequest
 import androidx.annotation.RequiresPermission
 import dagger.hilt.android.qualifiers.ApplicationContext
 import java.net.ConnectException
 import javax.inject.Inject
 import javax.inject.Singleton
+import kotlinx.coroutines.channels.awaitClose
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.callbackFlow
 
+enum class NetworkStatus {
+  AVAILABLE,
+  UNAVAILABLE
+}
 /** Abstracts access to network state. */
 @Singleton
 class NetworkManager @Inject constructor(@ApplicationContext private val context: Context) {
+  val networkStatusFlow = initNetworkStatusFlow()
+
+  fun initNetworkStatusFlow(): Flow<NetworkStatus> {
+    val connectivityManager = context.getSystemService(ConnectivityManager::class.java)
+    return callbackFlow {
+      val callback =
+        object : ConnectivityManager.NetworkCallback() {
+          override fun onAvailable(network: Network) {
+            trySend(NetworkStatus.AVAILABLE)
+          }
+
+          override fun onLost(network: Network) {
+            trySend(NetworkStatus.UNAVAILABLE)
+          }
+        }
+
+      val request = NetworkRequest.Builder().addCapability(NET_CAPABILITY_INTERNET).build()
+      // Emit initial state.
+      trySend(if (isNetworkConnected()) NetworkStatus.AVAILABLE else NetworkStatus.UNAVAILABLE)
+      connectivityManager.registerNetworkCallback(request, callback)
+
+      awaitClose { connectivityManager.unregisterNetworkCallback(callback) }
+    }
+  }
 
   /** Returns true iff the device has internet connectivity, false otherwise. */
   @RequiresPermission("android.permission.ACCESS_NETWORK_STATE")

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

@@ -32,9 +32,9 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.flatMapMerge
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.flow.onStart
 import kotlinx.coroutines.launch
 
 /** Represents view state and behaviors of the survey selector dialog. */
@@ -56,7 +56,7 @@ internal constructor(
 
   init {
     surveySummaries =
-      createSurveySummaries().onEach {
+      getSurveyList().onEach {
         if (it.isEmpty()) {
           setNotFound()
         } else {
@@ -67,29 +67,26 @@ internal constructor(
 
   /** Returns a flow of locally stored surveys. */
   private fun offlineSurveys(): Flow<List<Survey>> =
-    surveyRepository.offlineSurveys.onEach { setLoading() }
-
-  /** Returns a flow of remotely stored surveys. */
-  private suspend fun allSurveys(): Flow<List<Survey>> =
-    surveyRepository.getSurveySummaries(authManager.currentUser).onEach { setLoading() }
+    surveyRepository.localSurveysFlow.onEach { setLoading() }
 
   /** Returns a flow of [SurveyItem] to be displayed to the user. */
-  private fun createSurveySummaries(): Flow<List<SurveyItem>> =
-    offlineSurveys().flatMapMerge { offlineSurveys: List<Survey> ->
-      allSurveys().map { allSurveys: List<Survey> ->
-        allSurveys
-          .map { createSurveyItem(it, offlineSurveys) }
+  private fun getSurveyList(): Flow<List<SurveyItem>> =
+    surveyRepository
+      .getSurveyList(authManager.currentUser)
+      .onStart { setLoading() }
+      .map { surveys: List<Pair<Survey, Boolean>> ->
+        surveys
+          .map { createSurveyItem(it.first, it.second) }
           .sortedBy { it.surveyTitle }
           .sortedByDescending { it.isAvailableOffline }
       }
-    }
 
-  private fun createSurveyItem(survey: Survey, localSurveys: List<Survey>): SurveyItem =
+  private fun createSurveyItem(survey: Survey, isAvailableOffline: Boolean): SurveyItem =
     SurveyItem(
       surveyId = survey.id,
       surveyTitle = survey.title,
       surveyDescription = survey.description,
-      isAvailableOffline = localSurveys.any { it.id == survey.id }
+      isAvailableOffline = isAvailableOffline
     )
 
   /** Triggers the specified survey to be loaded and activated. */

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

@@ -79,7 +79,7 @@ class SurveyRepositoryTest : BaseHiltTest() {
     advanceUntilIdle()
 
     // Verify survey is deleted
-    surveyRepository.offlineSurveys.test { assertThat(expectMostRecentItem()).isEmpty() }
+    surveyRepository.localSurveysFlow.test { assertThat(expectMostRecentItem()).isEmpty() }
     // Verify survey deactivated
     assertThat(surveyRepository.activeSurvey).isNull()
   }
@@ -103,7 +103,7 @@ class SurveyRepositoryTest : BaseHiltTest() {
     // Verify active survey isn't cleared
     assertThat(surveyRepository.activeSurvey).isEqualTo(survey1)
     // Verify survey is deleted
-    surveyRepository.offlineSurveys.test {
+    surveyRepository.localSurveysFlow.test {
       assertThat(expectMostRecentItem()).isEqualTo(listOf(survey1))
     }
   }

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

@@ -77,7 +77,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
 
   @Test
   fun created_surveysAvailable_whenNoSurveySynced() {
-    setAllSurveys(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
+    setSurveyList(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
     setOfflineSurveys(listOf())
     setUpFragment()
 
@@ -99,7 +99,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
 
   @Test
   fun created_surveysAvailable_whenOneSurveySynced() {
-    setAllSurveys(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
+    setSurveyList(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
     setOfflineSurveys(listOf(TEST_SURVEY_2))
     setUpFragment()
 
@@ -121,7 +121,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
 
   @Test
   fun click_activatesSurvey() = runWithTestDispatcher {
-    setAllSurveys(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
+    setSurveyList(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
     setOfflineSurveys(listOf())
     setUpFragment()
 
@@ -138,7 +138,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
 
   @Test
   fun shouldExitAppOnBackPress_defaultFalse() {
-    setAllSurveys(listOf())
+    setSurveyList(listOf())
     setOfflineSurveys(listOf())
     setUpFragment()
 
@@ -148,7 +148,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
 
   @Test
   fun shouldExitAppOnBackPress_whenArgIsPresent() {
-    setAllSurveys(listOf())
+    setSurveyList(listOf())
     setOfflineSurveys(listOf())
     setUpFragment(bundleOf(Pair("shouldExitApp", true)))
 
@@ -158,7 +158,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
 
   @Test
   fun `hide sign out button when survey list is not empty`() {
-    setAllSurveys(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
+    setSurveyList(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
     setOfflineSurveys(listOf())
     setUpFragment()
 
@@ -167,7 +167,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
 
   @Test
   fun `show sign out button when survey list is empty`() {
-    setAllSurveys(listOf())
+    setSurveyList(listOf())
     setOfflineSurveys(listOf())
     setUpFragment()
 
@@ -177,7 +177,7 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
 
   @Test
   fun `remove offline survey on menu item click`() = runWithTestDispatcher {
-    setAllSurveys(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
+    setSurveyList(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
     setOfflineSurveys(listOf(TEST_SURVEY_1, TEST_SURVEY_2))
     setUpFragment()
 
@@ -210,13 +210,13 @@ class SurveySelectorFragmentTest : BaseHiltTest() {
     }
   }
 
-  private fun setAllSurveys(surveys: List<Survey>) = runWithTestDispatcher {
-    whenever(surveyRepository.getSurveySummaries(FakeData.USER))
+  private fun setSurveyList(surveys: List<Pair<Survey, Boolean>>) = runWithTestDispatcher {
+    whenever(surveyRepository.getSurveyList(FakeData.USER))
       .thenReturn(listOf(surveys).asFlow())
   }
 
   private fun setOfflineSurveys(surveys: List<Survey>) {
-    whenever(surveyRepository.offlineSurveys).thenReturn(listOf(surveys).asFlow())
+    whenever(surveyRepository.localSurveysFlow).thenReturn(listOf(surveys).asFlow())
   }
 
   private fun getViewHolder(index: Int): SurveyListAdapter.ViewHolder {

sharedTest/src/main/kotlin/com/sharedtest/persistence/remote/FakeRemoteDataStore.kt

@@ -22,6 +22,8 @@ import com.google.android.ground.model.locationofinterest.LocationOfInterest
 import com.google.android.ground.model.mutation.Mutation
 import com.google.android.ground.model.submission.Submission
 import com.google.android.ground.persistence.remote.RemoteDataStore
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flowOf
 import javax.inject.Inject
 import javax.inject.Singleton
 
@@ -38,7 +40,7 @@ class FakeRemoteDataStore @Inject internal constructor() : RemoteDataStore {
 
   private val subscribedSurveyIds = mutableSetOf<String>()
 
-  override suspend fun loadSurveySummaries(user: User): List<Survey> = surveys
+  override suspend fun getSurveyList(user: User): Flow<List<Survey>> = flowOf(surveys)
 
   override suspend fun loadSurvey(surveyId: String): Survey? = onLoadSurvey.invoke(surveyId)