Remove dependency on survey.tileSources, instead use default Firebase…

… storage path: /offline-imagery/default.

ground/src/main/java/com/google/android/ground/Config.kt

@@ -55,13 +55,14 @@ object Config {
   const val MAX_MEDIA_UPLOAD_RETRY_COUNT = 5
 
   // TODO(#1730): Make sub-paths configurable and stop hardcoding here.
+  const val DEFAULT_MOG_TILE_URL = "/offline-imagery/default/"
   const val DEFAULT_MOG_MIN_ZOOM = 8
   const val DEFAULT_MOG_MAX_ZOOM = 14
 
-  fun getMogSources(path: String = "/offline-imagery/default/") =
+  fun getMogSources(path: String) =
     listOf(
       MogSource(
-        0 ..< DEFAULT_MOG_MIN_ZOOM,
+        0..<DEFAULT_MOG_MIN_ZOOM,
         "$path/$DEFAULT_MOG_MIN_ZOOM/overview.tif",
       ),
       MogSource(

ground/src/main/java/com/google/android/ground/model/Survey.kt

@@ -24,6 +24,7 @@ data class Survey(
   val title: String,
   val description: String,
   val jobMap: Map<String, Job>,
+  // TODO(#1730): Allow tile source configuration from a non-survey accessible source.
   val tileSources: List<TileSource> = listOf(),
   val acl: Map<String, String> = mapOf()
 ) {

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

@@ -33,15 +33,15 @@ import com.google.android.ground.ui.util.FileUtil
 import com.google.android.ground.util.ByteCount
 import com.google.android.ground.util.deleteIfEmpty
 import com.google.android.ground.util.rangeOf
-import java.io.File
-import javax.inject.Inject
-import javax.inject.Singleton
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.map
 import timber.log.Timber
+import java.io.File
+import javax.inject.Inject
+import javax.inject.Singleton
 
 /**
  * Corners of the viewport are scaled by this value when determining the name of downloaded areas.
@@ -51,8 +51,7 @@ const val AREA_NAME_SENSITIVITY = 0.5
 
 @Singleton
 class OfflineAreaRepository
-@Inject
-constructor(
+@Inject constructor(
   private val localOfflineAreaStore: LocalOfflineAreaStore,
   private val surveyRepository: SurveyRepository,
   private val fileUtil: FileUtil,
@@ -109,18 +108,16 @@ constructor(
 
   fun getOfflineTileSourcesFlow() =
     surveyRepository.activeSurveyFlow.combine(getOfflineAreaBounds()) { survey, bounds ->
-      applyBounds(survey?.tileSources, bounds)
+      applyBounds(getDefaultTileSources(), bounds)
     }
 
   private suspend fun applyBounds(
-    tileSources: List<TileSource>?,
-    bounds: List<Bounds>
+    tileSources: List<TileSource>?, bounds: List<Bounds>
   ): List<TileSource> =
     tileSources?.mapNotNull { tileSource -> toOfflineTileSource(tileSource, bounds) } ?: listOf()
 
   private suspend fun toOfflineTileSource(
-    tileSource: TileSource,
-    clipBounds: List<Bounds>
+    tileSource: TileSource, clipBounds: List<Bounds>
   ): TileSource? {
     if (tileSource.type != TileSource.Type.MOG_COLLECTION) return null
     return TileSource(
@@ -143,15 +140,15 @@ constructor(
     return MogClient(mogCollection, remoteStorageManager)
   }
 
-  private fun getMogSources(): List<MogSource> = Config.getMogSources(getFirstTileSourceUrl())
+  private fun getMogSources(): List<MogSource> =
+    Config.getMogSources(getDefaultTileSources().first().url)
 
   /**
-   * Returns the URL of the first tile source in the current survey, or throws an error if no survey
-   * is active or if no tile sources are defined.
+   * Returns the default configured tile sources.
+   *
    */
-  private fun getFirstTileSourceUrl() =
-    surveyRepository.activeSurvey?.tileSources?.firstOrNull()?.url
-      ?: error("Survey has no tile sources")
+  fun getDefaultTileSources(): List<TileSource> =
+    listOf(TileSource(url = Config.DEFAULT_MOG_TILE_URL, type = TileSource.Type.MOG_COLLECTION))
 
   suspend fun hasHiResImagery(bounds: Bounds): Boolean {
     val client = getMogClient()

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

@@ -22,12 +22,12 @@ import com.google.android.ground.repository.SurveyRepository
 import com.google.android.ground.ui.common.AbstractViewModel
 import com.google.android.ground.ui.common.Navigator
 import com.google.android.ground.ui.common.SharedViewModel
-import javax.inject.Inject
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.SharedFlow
 import kotlinx.coroutines.flow.asSharedFlow
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.launch
+import javax.inject.Inject
 
 @SharedViewModel
 class HomeScreenViewModel
@@ -40,8 +40,9 @@ internal constructor(
   private val _openDrawerRequests: MutableSharedFlow<Unit> = MutableSharedFlow()
   val openDrawerRequestsFlow: SharedFlow<Unit> = _openDrawerRequests.asSharedFlow()
 
+  // TODO(#1730): Allow tile source configuration from a non-survey accessible source.
   val showOfflineAreaMenuItem: LiveData<Boolean> =
-    surveyRepository.activeSurveyFlow.map { it?.tileSources?.isNotEmpty() ?: false }.asLiveData()
+    surveyRepository.activeSurveyFlow.map { true }.asLiveData()
 
   fun openNavDrawer() {
     viewModelScope.launch { _openDrawerRequests.emit(Unit) }

ground/src/main/java/com/google/android/ground/ui/offlineareas/selector/OfflineAreaSelectorViewModel.kt

@@ -37,9 +37,9 @@ import com.google.android.ground.ui.map.CameraPosition
 import com.google.android.ground.ui.map.MapType
 import com.google.android.ground.util.toMb
 import com.google.android.ground.util.toMbString
-import javax.inject.Inject
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.launch
+import javax.inject.Inject
 
 private const val MIN_DOWNLOAD_ZOOM_LEVEL = 9
 private const val MAX_AREA_DOWNLOAD_SIZE_MB = 50
@@ -90,7 +90,7 @@ internal constructor(
       )
 
   init {
-    remoteTileSources = surveyRepository.activeSurvey!!.tileSources
+    remoteTileSources = offlineAreaRepository.getDefaultTileSources()
   }
 
   fun onDownloadClick() {