Fix crash on SubmitDataUseCase

app/src/main/java/org/groundplatform/android/repository/SubmissionRepository.kt

@@ -70,16 +70,27 @@ constructor(
     } ?: run { Timber.w("Job not found for survey $surveyId and LOI $locationOfInterestId") }
   }
 
-  override suspend fun getDraftSubmission(
-    draftSubmissionId: String,
+  override suspend fun getDraftSubmission(survey: Survey): DraftSubmission? {
+    val draftId = localValueStore.draftSubmissionId
+    val draft =
+      if (draftId.isNullOrEmpty()) null
+      else localSubmissionStore.getDraftSubmission(draftSubmissionId = draftId, survey = survey)
+    if (draft != null && draft.surveyId != survey.id) {
+      Timber.e("Skipping draft submission, survey id doesn't match")
+      return null
+    }
+    return draft
+  }
+
+  override suspend fun getDraftSubmissionForSession(
     survey: Survey,
+    jobId: String,
+    loiId: String?,
   ): DraftSubmission? =
-    localSubmissionStore.getDraftSubmission(draftSubmissionId = draftSubmissionId, survey = survey)
+    getDraftSubmission(survey)?.takeIf { it.jobId == jobId && it.loiId == loiId }
 
   override suspend fun countDraftSubmissions() = localSubmissionStore.countDraftSubmissions()
 
-  override fun getDraftSubmissionsId() = localValueStore.draftSubmissionId ?: ""
-
   override suspend fun saveDraftSubmission(
     jobId: String,
     loiId: String?,

app/src/main/java/org/groundplatform/android/ui/datacollection/DataCollectionInitializer.kt

@@ -25,10 +25,18 @@ import org.groundplatform.android.ui.common.LocationOfInterestHelper
 import org.groundplatform.android.ui.datacollection.DataCollectionInitializer.Companion.TASK_POSITION_ID
 import org.groundplatform.domain.model.Survey
 import org.groundplatform.domain.model.job.Job
+import org.groundplatform.domain.model.submission.TaskData
+import org.groundplatform.domain.model.submission.ValueDelta
 import org.groundplatform.domain.model.task.Task
 import org.groundplatform.domain.repository.LocationOfInterestRepositoryInterface
+import org.groundplatform.domain.repository.SubmissionRepositoryInterface
 import org.groundplatform.domain.repository.SurveyRepositoryInterface
 
+data class DataCollectionInitializerResult(
+  val uiState: DataCollectionUiState,
+  val collectedData: Map<Task, TaskData> = emptyMap(),
+)
+
 /**
  * DataCollectionInitializer
  *
@@ -38,7 +46,8 @@ import org.groundplatform.domain.repository.SurveyRepositoryInterface
  * - Load active survey (with timeout).
  * - Resolve job by id.
  * - Pick displayable tasks (exclude Add-LOI when LOI exists).
- * - Choose initial task id from SavedStateHandle (if valid) or first task.
+ * - Restore the data collected so far from the draft of an interrupted session, if any.
+ * - Choose initial task id from SavedStateHandle or the draft (if valid), or first task.
  * - Compute a simple [TaskPosition] from list order.
  * - Resolve a user-visible LOI name (typed for Add-LOI, formatted for existing LOI).
  */
@@ -47,31 +56,33 @@ class DataCollectionInitializer
 constructor(
   private val locationOfInterestHelper: LocationOfInterestHelper,
   private val locationOfInterestRepository: LocationOfInterestRepositoryInterface,
+  private val submissionRepository: SubmissionRepositoryInterface,
   private val surveyRepository: SurveyRepositoryInterface,
 ) {
 
   /**
-   * Computes the initial [DataCollectionUiState] without building any sequence.
+   * Computes the initial [DataCollectionInitializerResult] without building any sequence.
    *
    * Reads from [savedStateHandle]:
    * - [TASK_POSITION_ID]: previously visited task id (optional).
-   * - [TASK_LOI_NAME_KEY]: user-typed LOI name for Add-LOI flows (optional).
    */
   suspend fun initialize(
     savedStateHandle: SavedStateHandle,
     jobId: String,
     loiId: String?,
     loiName: String?,
-  ): DataCollectionUiState =
+  ): DataCollectionInitializerResult =
     try {
       val survey = loadSurveyOrThrow()
       val job = resolveJobOrThrow(survey, jobId)
       val tasks = pickTasks(job, loiId)
       if (tasks.isEmpty()) throw DataCollectionException.NoValidTasks
 
+      val draft = submissionRepository.getDraftSubmissionForSession(survey, jobId, loiId)
+
       val savedTaskId: String? = savedStateHandle[TASK_POSITION_ID]
       val currentTaskId =
-        resolveInitialTaskId(tasks, savedTaskId)
+        resolveInitialTaskId(tasks, savedTaskId, draft?.currentTaskId)
           ?: throw DataCollectionException.Wrapped(
             DataCollectionErrorCode.INITIAL_TASK_RESOLUTION_FAILED,
             IllegalStateException("No valid initial task id"),
@@ -89,21 +100,24 @@ constructor(
 
       val loiName = computeLoiName(survey.id, loiId, loiName)
 
-      DataCollectionUiState.Ready(
-        surveyId = survey.id,
-        job = job,
-        loiName = loiName,
-        tasks = tasks,
-        isAddLoiFlow = loiId == null,
-        currentTaskId = currentTaskId,
-        position = position,
+      DataCollectionInitializerResult(
+        DataCollectionUiState.Ready(
+          surveyId = survey.id,
+          job = job,
+          loiName = loiName,
+          tasks = tasks,
+          isAddLoiFlow = loiId == null,
+          currentTaskId = currentTaskId,
+          position = position,
+        ),
+        collectedData = restoreData(tasks, draft?.deltas.orEmpty()),
       )
     } catch (e: DataCollectionException) {
-      DataCollectionUiState.Error(e.code, e)
+      DataCollectionInitializerResult(DataCollectionUiState.Error(e.code, e))
     } catch (c: CancellationException) {
       throw c
     } catch (t: Throwable) {
-      DataCollectionUiState.Error(mapThrowableToCode(t), t)
+      DataCollectionInitializerResult(DataCollectionUiState.Error(mapThrowableToCode(t), t))
     }
 
   private suspend fun loadSurveyOrThrow(): Survey =
@@ -122,14 +136,21 @@ constructor(
   private fun pickTasks(job: Job, loiId: String?): List<Task> =
     if (loiId == null) job.tasksSorted else job.tasksSorted.filterNot { it.isAddLoiTask }
 
+  private fun restoreData(tasks: List<Task>, deltas: List<ValueDelta>): Map<Task, TaskData> {
+    val deltaMap = deltas.associateBy { it.taskId to it.taskType }
+    return tasks
+      .mapNotNull { task -> deltaMap[task.id to task.type]?.newTaskData?.let { task to it } }
+      .toMap()
+  }
+
   /**
    * Choose initial task:
-   * - Use [saved] if it exists within [tasks].
+   * - Use the first of [candidates] which exists within [tasks].
    * - Otherwise, first task in list.
    */
-  private fun resolveInitialTaskId(tasks: List<Task>, saved: String?): String? {
+  private fun resolveInitialTaskId(tasks: List<Task>, vararg candidates: String?): String? {
     val validIds = tasks.map { it.id }.toSet()
-    return saved?.takeIf { it in validIds } ?: tasks.firstOrNull()?.id
+    return candidates.filterNotNull().firstOrNull { it in validIds } ?: tasks.firstOrNull()?.id
   }
 
   /**

app/src/main/java/org/groundplatform/android/ui/datacollection/DataCollectionViewModel.kt

@@ -32,7 +32,6 @@ import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
-import org.groundplatform.android.data.local.room.converter.SubmissionDeltasConverter
 import org.groundplatform.android.data.uuid.OfflineUuidGenerator
 import org.groundplatform.android.di.coroutines.ApplicationScope
 import org.groundplatform.android.di.coroutines.IoDispatcher
@@ -51,7 +50,6 @@ import org.groundplatform.android.ui.datacollection.tasks.point.DropPinTaskViewM
 import org.groundplatform.android.ui.datacollection.tasks.polygon.DrawAreaTaskViewModel
 import org.groundplatform.android.ui.datacollection.tasks.text.TextTaskViewModel
 import org.groundplatform.android.ui.datacollection.tasks.time.TimeTaskViewModel
-import org.groundplatform.domain.model.job.Job
 import org.groundplatform.domain.model.submission.TaskData
 import org.groundplatform.domain.model.submission.ValueDelta
 import org.groundplatform.domain.model.submission.isNotNullOrEmpty
@@ -108,8 +106,6 @@ internal constructor(
   private val _loiNameDraft = MutableStateFlow("")
   val loiNameDraft: StateFlow<String> = _loiNameDraft
 
-  private var shouldLoadFromDraft: Boolean = savedStateHandle[TASK_SHOULD_LOAD_FROM_DRAFT] ?: false
-
   private val jobId: String = requireNotNull(savedStateHandle[TASK_JOB_ID_KEY])
   private val loiId: String? = savedStateHandle[TASK_LOI_ID_KEY]
 
@@ -129,20 +125,32 @@ internal constructor(
           getTypedLoiNameOrEmpty(),
         )
 
-      if (initResult is DataCollectionUiState.Ready) {
-        if (shouldLoadFromDraft) {
-          initializeDraftValues(initResult.job, initResult.tasks)
+      _uiState.value =
+        when (val state = initResult.uiState) {
+          is DataCollectionUiState.Ready -> {
+            taskDataHandler.setData(initResult.collectedData)
+            taskSequenceHandler = TaskSequenceHandler(state.tasks, taskDataHandler)
+            setupSession(state)
+          }
+          is DataCollectionUiState.Error -> {
+            Timber.e(state.cause, "Initialization failed code=%s", state.code)
+            state
+          }
+          else -> {
+            state
+          }
         }
-        taskSequenceHandler = TaskSequenceHandler(initResult.tasks, taskDataHandler)
-      }
-
-      if (initResult is DataCollectionUiState.Error) {
-        Timber.e(initResult.cause, "Initialization failed code=%s", initResult.code)
-      }
-      _uiState.value = initResult
     }
   }
 
+  private fun setupSession(state: DataCollectionUiState.Ready): DataCollectionUiState.Ready {
+    val taskId = taskSequenceHandler.getResumeTask(state.currentTaskId)
+    if (taskId == state.currentTaskId) return state
+
+    Timber.w("No data restored for task %s; resuming at %s", state.currentTaskId, taskId)
+    return state.withTask(taskId)
+  }
+
   private fun setLoiName(name: String) {
     savedStateHandle[TASK_LOI_NAME_KEY] = name
     _uiState.update { state ->
@@ -410,11 +418,9 @@ internal constructor(
     val validIds = taskSequenceHandler.getValidTasks().map { it.id }.toSet()
     val safeId = if (taskId in validIds) taskId else validIds.first()
 
-    savedStateHandle[TASK_POSITION_ID] = safeId
+    val newState = st.withTask(safeId)
     saveDraft(safeId)
-
-    val newPos = taskSequenceHandler.getTaskPosition(safeId)
-    _uiState.value = st.copy(currentTaskId = safeId, position = newPos)
+    _uiState.value = newState
   }
 
   private fun getDeltas(): List<ValueDelta> {
@@ -464,33 +470,6 @@ internal constructor(
     return block(s)
   }
 
-  private fun initializeDraftValues(job: Job, tasks: List<Task>) {
-    val serialized: String? = savedStateHandle[TASK_DRAFT_VALUES]
-    if (serialized.isNullOrBlank()) {
-      Timber.w("No draft values found; skipping load")
-      return
-    }
-
-    val parsed =
-      try {
-        SubmissionDeltasConverter.fromString(job, serialized)
-      } catch (e: Exception) {
-        Timber.e(e, "Failed to parse draft submission")
-        emptyList()
-      }
-
-    val deltaMap = parsed.associateBy { it.taskId to it.taskType }
-
-    val draftValues =
-      tasks
-        .mapNotNull { task -> deltaMap[task.id to task.type]?.newTaskData?.let { task to it } }
-        .toMap()
-
-    if (draftValues.isNotEmpty()) {
-      taskDataHandler.setData(draftValues)
-    }
-  }
-
   private inline fun validateOrShow(taskVm: AbstractTaskViewModel, onValid: () -> Unit) {
     val error = taskVm.validate()
     if (error != null) {
@@ -505,13 +484,16 @@ internal constructor(
       .map { (it as? DataCollectionUiState.Ready)?.currentTaskId == taskId }
       .distinctUntilChanged()
 
+  private fun DataCollectionUiState.Ready.withTask(taskId: String): DataCollectionUiState.Ready {
+    savedStateHandle[TASK_POSITION_ID] = taskId
+    return copy(currentTaskId = taskId, position = taskSequenceHandler.getTaskPosition(taskId))
+  }
+
   companion object {
     private const val TASK_JOB_ID_KEY = "jobId"
     private const val TASK_LOI_ID_KEY = "locationOfInterestId"
     private const val TASK_LOI_NAME_KEY = "locationOfInterestName"
     private const val TASK_POSITION_ID = "currentTaskId"
-    private const val TASK_DRAFT_VALUES = "draftValues"
-    private const val TASK_SHOULD_LOAD_FROM_DRAFT = "shouldLoadFromDraft"
 
     fun getViewModelClass(taskType: Task.Type): Class<out AbstractTaskViewModel> =
       when (taskType) {

app/src/main/java/org/groundplatform/android/ui/datacollection/TaskSequenceHandler.kt

@@ -82,6 +82,21 @@ class TaskSequenceHandler(
     return validTasks
   }
 
+  /**
+   * Returns the task ID to resume. Ensures sequences never skip past tasks with required answers,
+   * so incomplete answers get recollected instead of omitted.
+   */
+  fun getResumeTask(taskId: String): String {
+    validateTaskId(taskId)
+    val sequence = getValidTasks()
+    val target = sequence.firstOrNull { it.id == taskId } ?: sequence.first()
+    val unanswered =
+      sequence
+        .takeWhile { it != target }
+        .firstOrNull { (it.isRequired || it.isAddLoiTask) && taskDataHandler.getData(it) == null }
+    return (unanswered ?: target).id
+  }
+
   /** Resets the local cache of the task list. */
   fun invalidateCache() {
     isTaskListReady = false

app/src/main/java/org/groundplatform/android/ui/home/HomeScreenFragment.kt

@@ -33,7 +33,6 @@ import dagger.hilt.android.AndroidEntryPoint
 import javax.inject.Inject
 import kotlinx.coroutines.launch
 import org.groundplatform.android.R
-import org.groundplatform.android.data.local.room.converter.SubmissionDeltasConverter
 import org.groundplatform.android.databinding.HomeScreenFragBinding
 import org.groundplatform.android.ui.common.AbstractFragment
 import org.groundplatform.android.ui.common.BackPressListener
@@ -152,9 +151,6 @@ class HomeScreenFragment : AbstractFragment(), BackPressListener {
               draft.loiId,
               draft.loiName ?: "",
               draft.jobId,
-              true,
-              SubmissionDeltasConverter.toString(draft.deltas),
-              draft.currentTaskId ?: "",
             )
           )
 

app/src/main/java/org/groundplatform/android/ui/home/HomeScreenViewModel.kt

@@ -48,7 +48,6 @@ import org.groundplatform.domain.repository.OfflineAreaRepositoryInterface
 import org.groundplatform.domain.repository.SubmissionRepositoryInterface
 import org.groundplatform.domain.repository.SurveyRepositoryInterface
 import org.groundplatform.domain.repository.UserRepositoryInterface
-import timber.log.Timber
 
 data class HomeDrawerState(val user: User, val survey: Survey?, val appVersion: String)
 
@@ -129,24 +128,10 @@ internal constructor(
 
   /** Attempts to return draft submission for the currently active active survey. */
   suspend fun getDraftSubmission(): DraftSubmission? {
-    val draftId = submissionRepository.getDraftSubmissionsId()
-    val survey = surveyRepository.activeSurveyFlow.first()
-
-    if (survey == null || draftId.isEmpty()) {
-      // No active survey or draft submission.
-      return null
-    }
-
-    val draft = submissionRepository.getDraftSubmission(draftId, survey) ?: return null
-
-    if (draft.surveyId != survey.id) {
-      Timber.e("Skipping draft submission, survey id doesn't match")
-      return null
-    }
-
     // TODO: Check whether the previous user id matches with current user or not.
     // Issue URL: https://github.com/google/ground-android/issues/2903
-    return draft
+    val survey = surveyRepository.activeSurveyFlow.first() ?: return null
+    return submissionRepository.getDraftSubmission(survey)
   }
 
   fun openNavDrawer() {

app/src/main/java/org/groundplatform/android/ui/home/mapcontainer/HomeScreenMapContainerFragment.kt

@@ -192,9 +192,6 @@ class HomeScreenMapContainerFragment : AbstractMapContainerFragment() {
               cardUiData.loi.id,
               cardUiData.loi.properties[LOI_NAME_PROPERTY] as? String?,
               cardUiData.loi.job.id,
-              false,
-              null,
-              "",
             )
           )
       is AdHocDataCollectionButtonData ->
@@ -204,9 +201,6 @@ class HomeScreenMapContainerFragment : AbstractMapContainerFragment() {
               null,
               null,
               cardUiData.job.id,
-              false,
-              null,
-              "",
             )
           )
     }