Fix oppia#3327: Create app layer mechanism for saving checkpoints. (o…

…ppia#3402)

* add controller and tests

* NIT

* added tests for constant

* moved enum to a different file

* fixed lint

* fixed comments

* saving

* added mech to save checkpoints

* lint fix

* added module to UI-tests

* added exploration storage module to ui tests

* nit

* added module in missed files

* lint fix

* fixed saving

* added app layer saving mechanism

* added app layer saving mechanism

* lint fix

* fix lint in domain layer

* lint fix

* nit changes

* lint fix

* implemented dialog boxes

* lint fix

* added tests for saving checkpoints

* nit changes

* lint fix

* nit changes

* lint fix

* lint fix

* fixed failing test

* imporved approach and added tests

* nit changes

* nit changes

* fixed function names

* fixed failing domain tests and some nits

* completed saving approach

* added more tests and fixed failing tests

* checkpointing disabled by default

* fix

* nit

* added more tests

* added default value to boolean

* improved mechanism to save checkpoints

* nit changes

* nit

* completed app layer implementation

* nit

* fixed failing test

* nit changes

* suppressed ExperimantalCoroutinesApi warning

* added more tests

* nit

* nit

* nit

* nit

* nit

* nit

* nit

* removed commit

* added more tests

* removed visibleForTesting

* nit

* Revert "removed visibleForTesting"

This reverts commit 7963300.

* added TODO for the issue

* removed git add .

* nit

* nit

* added missing module in develop

* nit

* nit

* reverted changes back in StateDeck.kt

* fixed failing tests

* fixed failing test

* fixed failing tests

* added more tests

* nit

* added tests and exempted ui files

* nit

* nit

* changed approach to stop exploration and nit changes

* nit

* nit

* changed approach to stop exploration and nits

* lint fix

* nit

* nits in comments

* nit

* applied suggestion in stateDeck

* nit

* nit

* nit

* nit

* fixed dialog box

* disabled checkpointing, it was enabled for testing locally

app/src/main/java/org/oppia/android/app/home/RouteToExplorationListener.kt

@@ -7,6 +7,7 @@ interface RouteToExplorationListener {
  topicId: String,
  storyId: String,
  explorationId: String,
- backflowScreen: Int?
+ backflowScreen: Int?,
+ isCheckpointingEnabled: Boolean
  )
 }

app/src/main/java/org/oppia/android/app/home/recentlyplayed/RecentlyPlayedActivity.kt

@@ -42,7 +42,8 @@ class RecentlyPlayedActivity : InjectableAppCompatActivity(), RouteToExploration
  topicId: String,
  storyId: String,
  explorationId: String,
- backflowScreen: Int?
+ backflowScreen: Int?,
+ isCheckpointingEnabled: Boolean
  ) {
  startActivity(
  ExplorationActivity.createExplorationActivityIntent(
@@ -51,7 +52,8 @@ class RecentlyPlayedActivity : InjectableAppCompatActivity(), RouteToExploration
  topicId,
  storyId,
  explorationId,
- backflowScreen
+ backflowScreen,
+ isCheckpointingEnabled
  )
  )
  }

app/src/main/java/org/oppia/android/app/home/recentlyplayed/RecentlyPlayedFragmentPresenter.kt

@@ -242,7 +242,8 @@ class RecentlyPlayedFragmentPresenter @Inject constructor(
  topicId,
  storyId,
  explorationId,
- /* backflowScreen = */ null
+ /* backflowScreen = */ null,
+ isCheckpointingEnabled = false
  )
  activity.finish()
  }

app/src/main/java/org/oppia/android/app/player/exploration/ExplorationActivity.kt

@@ -16,18 +16,16 @@ import org.oppia.android.app.model.State
 import org.oppia.android.app.player.audio.AudioButtonListener
 import org.oppia.android.app.player.state.listener.RouteToHintsAndSolutionListener
 import org.oppia.android.app.player.state.listener.StateKeyboardButtonListener
-import org.oppia.android.app.player.stopplaying.StopExplorationDialogFragment
-import org.oppia.android.app.player.stopplaying.StopStatePlayingSessionListener
+import org.oppia.android.app.player.stopplaying.StopStatePlayingSessionWithSavedProgressListener
 import org.oppia.android.app.topic.conceptcard.ConceptCardListener
 import javax.inject.Inject
 
-private const val TAG_STOP_EXPLORATION_DIALOG = "STOP_EXPLORATION_DIALOG"
 const val TAG_HINTS_AND_SOLUTION_DIALOG = "HINTS_AND_SOLUTION_DIALOG"
 
 /** The starting point for exploration. */
 class ExplorationActivity :
  InjectableAppCompatActivity(),
- StopStatePlayingSessionListener,
+ StopStatePlayingSessionWithSavedProgressListener,
  StateKeyboardButtonListener,
  AudioButtonListener,
  HintsAndSolutionListener,
@@ -46,6 +44,7 @@ class ExplorationActivity :
  private lateinit var explorationId: String
  private lateinit var state: State
  private var backflowScreen: Int? = null
+ private var isCheckpointingEnabled: Boolean = false
 
  override fun onCreate(savedInstanceState: Bundle?) {
  super.onCreate(savedInstanceState)
@@ -55,13 +54,16 @@ class ExplorationActivity :
  storyId = intent.getStringExtra(EXPLORATION_ACTIVITY_STORY_ID_ARGUMENT_KEY)
  explorationId = intent.getStringExtra(EXPLORATION_ACTIVITY_EXPLORATION_ID_ARGUMENT_KEY)
  backflowScreen = intent.getIntExtra(EXPLORATION_ACTIVITY_BACKFLOW_SCREEN_KEY, -1)
+ isCheckpointingEnabled =
+ intent.getBooleanExtra(EXPLORATION_ACTIVITY_IS_CHECKPOINTING_ENABLED_KEY, false)
  explorationActivityPresenter.handleOnCreate(
  this,
  internalProfileId,
  topicId,
  storyId,
  explorationId,
- backflowScreen
+ backflowScreen,
+ isCheckpointingEnabled
  )
  }
 
@@ -77,40 +79,39 @@ class ExplorationActivity :
  "ExplorationActivity.exploration_id"
  const val EXPLORATION_ACTIVITY_BACKFLOW_SCREEN_KEY =
  "ExplorationActivity.backflow_screen"
+ const val EXPLORATION_ACTIVITY_IS_CHECKPOINTING_ENABLED_KEY =
+ "ExplorationActivity.is_checkpointing_enabled_key"
 
  fun createExplorationActivityIntent(
  context: Context,
  profileId: Int,
  topicId: String,
  storyId: String,
  explorationId: String,
- backflowScreen: Int?
+ backflowScreen: Int?,
+ isCheckpointingEnabled: Boolean
  ): Intent {
  val intent = Intent(context, ExplorationActivity::class.java)
  intent.putExtra(EXPLORATION_ACTIVITY_PROFILE_ID_ARGUMENT_KEY, profileId)
  intent.putExtra(EXPLORATION_ACTIVITY_TOPIC_ID_ARGUMENT_KEY, topicId)
  intent.putExtra(EXPLORATION_ACTIVITY_STORY_ID_ARGUMENT_KEY, storyId)
  intent.putExtra(EXPLORATION_ACTIVITY_EXPLORATION_ID_ARGUMENT_KEY, explorationId)
  intent.putExtra(EXPLORATION_ACTIVITY_BACKFLOW_SCREEN_KEY, backflowScreen)
+ intent.putExtra(EXPLORATION_ACTIVITY_IS_CHECKPOINTING_ENABLED_KEY, isCheckpointingEnabled)
  return intent
  }
  }
 
  override fun onBackPressed() {
- showStopExplorationDialogFragment()
+ explorationActivityPresenter.backButtonPressed()
  }
 
- private fun showStopExplorationDialogFragment() {
- val previousFragment = supportFragmentManager.findFragmentByTag(TAG_STOP_EXPLORATION_DIALOG)
- if (previousFragment != null) {
- supportFragmentManager.beginTransaction().remove(previousFragment).commitNow()
- }
- val dialogFragment = StopExplorationDialogFragment.newInstance()
- dialogFragment.showNow(supportFragmentManager, TAG_STOP_EXPLORATION_DIALOG)
+ override fun deleteCurrentProgressAndStopSession() {
+ explorationActivityPresenter.deleteCurrentProgressAndStopExploration()
  }
 
- override fun stopSession() {
- explorationActivityPresenter.stopExploration()
+ override fun deleteOldestProgressAndStopSession() {
+ explorationActivityPresenter.deleteOldestSavedProgressAndStopExploration()
  }
 
  override fun onCreateOptionsMenu(menu: Menu?): Boolean {

app/src/main/java/org/oppia/android/app/player/exploration/ExplorationActivityPresenter.kt

@@ -14,9 +14,13 @@ import androidx.lifecycle.Transformations
 import org.oppia.android.R
 import org.oppia.android.app.activity.ActivityScope
 import org.oppia.android.app.help.HelpActivity
+import org.oppia.android.app.model.CheckpointState
 import org.oppia.android.app.model.Exploration
+import org.oppia.android.app.model.ProfileId
 import org.oppia.android.app.model.ReadingTextSize
 import org.oppia.android.app.options.OptionsActivity
+import org.oppia.android.app.player.stopplaying.ProgressDatabaseFullDialogFragment
+import org.oppia.android.app.player.stopplaying.UnsavedExplorationDialogFragment
 import org.oppia.android.app.topic.TopicActivity
 import org.oppia.android.app.utility.FontScaleConfigurationUtil
 import org.oppia.android.app.viewmodel.ViewModelProvider
@@ -27,8 +31,11 @@ import org.oppia.android.util.data.AsyncResult
 import org.oppia.android.util.data.DataProviders.Companion.toLiveData
 import javax.inject.Inject
 
-const val TAG_EXPLORATION_FRAGMENT = "TAG_EXPLORATION_FRAGMENT"
-const val TAG_EXPLORATION_MANAGER_FRAGMENT = "TAG_EXPLORATION_MANAGER_FRAGMENT"
+private const val TAG_UNSAVED_EXPLORATION_DIALOG = "UNSAVED_EXPLORATION_DIALOG"
+private const val TAG_STOP_EXPLORATION_DIALOG = "STOP_EXPLORATION_DIALOG"
+private const val TAG_PROGRESS_DATABASE_FULL_DIALOG = "PROGRESS_DATABASE_FULL_DIALOG"
+private const val TAG_EXPLORATION_FRAGMENT = "TAG_EXPLORATION_FRAGMENT"
+private const val TAG_EXPLORATION_MANAGER_FRAGMENT = "TAG_EXPLORATION_MANAGER_FRAGMENT"
 const val TAG_HINTS_AND_SOLUTION_EXPLORATION_MANAGER = "HINTS_AND_SOLUTION_EXPLORATION_MANAGER"
 
 /** The Presenter for [ExplorationActivity]. */
@@ -49,6 +56,11 @@ class ExplorationActivityPresenter @Inject constructor(
  private lateinit var context: Context
  private var backflowScreen: Int? = null
 
+ private var isCheckpointingEnabled: Boolean = false
+
+ private lateinit var oldestCheckpointExplorationId: String
+ private lateinit var oldestCheckpointExplorationTitle: String
+
  enum class ParentActivityForExploration(val value: Int) {
  BACKFLOW_SCREEN_LESSONS(0),
  BACKFLOW_SCREEN_STORY(1);
@@ -64,7 +76,8 @@ class ExplorationActivityPresenter @Inject constructor(
  topicId: String,
  storyId: String,
  explorationId: String,
- backflowScreen: Int?
+ backflowScreen: Int?,
+ isCheckpointingEnabled: Boolean
  ) {
  val binding = DataBindingUtil.setContentView<ExplorationActivityBinding>(
  activity,
@@ -98,6 +111,11 @@ class ExplorationActivityPresenter @Inject constructor(
  this.explorationId = explorationId
  this.context = context
  this.backflowScreen = backflowScreen
+ this.isCheckpointingEnabled = isCheckpointingEnabled
+
+ // Retrieve oldest saved checkpoint details.
+ subscribeToOldestSavedExplorationDetails()
+
  if (getExplorationManagerFragment() == null) {
  val explorationManagerFragment = ExplorationManagerFragment()
  val args = Bundle()
@@ -195,6 +213,29 @@ class ExplorationActivityPresenter @Inject constructor(
  ) as HintsAndSolutionExplorationManagerFragment?
  }
 
+ /** Deletes the saved progress for the current exploration and then stops the exploration. */
+ fun deleteCurrentProgressAndStopExploration() {
+ explorationDataController.deleteExplorationProgressById(
+ ProfileId.newBuilder().setInternalId(internalProfileId).build(),
+ explorationId
+ )
+ stopExploration()
+ }
+
+ /** Deletes the oldest saved checkpoint and then stops the exploration. */
+ fun deleteOldestSavedProgressAndStopExploration() {
+ // If oldestCheckpointExplorationId is not initialized, it means that there was an error while
+ // retrieving the oldest saved checkpoint details. In this case, the exploration is exited
+ // without deleting the any checkpoints.
+ oldestCheckpointExplorationId.let {
+ explorationDataController.deleteExplorationProgressById(
+ ProfileId.newBuilder().setInternalId(internalProfileId).build(),
+ oldestCheckpointExplorationId
+ )
+ }
+ stopExploration()
+ }
+
  fun stopExploration() {
  fontScaleConfigurationUtil.adjustFontScale(activity, ReadingTextSize.MEDIUM_TEXT_SIZE.name)
  explorationDataController.stopPlayingExploration()
@@ -227,6 +268,25 @@ class ExplorationActivityPresenter @Inject constructor(
  }
  }
 
+ /**
+ * Shows an appropriate dialog box or exits the exploration directly without showing any dialog
+ * box when back button is pressed. This function shows [UnsavedExplorationDialogFragment] if
+ * checkpointing is not enabled otherwise it either exits the exploration or shows
+ * [ProgressDatabaseFullDialogFragment] depending upon the state of the saved checkpoint for the
+ * current exploration.
+ */
+ fun backButtonPressed() {
+ // If checkpointing is not enabled, show StopExplorationDialogFragment to exit the exploration,
+ // this is expected to happen if the exploration is marked as completed.
+ if (!isCheckpointingEnabled) {
+ showUnsavedExplorationDialogFragment()
+ return
+ }
+ // If checkpointing is enabled, get the current checkpoint state to show an appropriate dialog
+ // fragment.
+ showDialogFragmentBasedOnCurrentCheckpointState()
+ }
+
  fun dismissConceptCard() {
  getExplorationFragment()?.dismissConceptCard()
  }
@@ -299,4 +359,107 @@ class ExplorationActivityPresenter @Inject constructor(
  ) as ExplorationFragment
  explorationFragment.revealSolution()
  }
+
+ private fun showProgressDatabaseFullDialogFragment() {
+ val previousFragment = activity.supportFragmentManager.findFragmentByTag(
+ TAG_PROGRESS_DATABASE_FULL_DIALOG
+ )
+ if (previousFragment != null) {
+ activity.supportFragmentManager.beginTransaction().remove(previousFragment).commitNow()
+ }
+ // If any one of oldestCheckpointExplorationId or oldestCheckpointExplorationTitle is not
+ // initialized, it means that there was an error while retrieving the oldest saved checkpoint
+ // details. In that case the exploration will be exited without deleting the any checkpoints.
+ if (
+ !::oldestCheckpointExplorationId.isInitialized ||
+ !::oldestCheckpointExplorationTitle.isInitialized
+ ) {
+ stopExploration()
+ return
+ }
+
+ val dialogFragment =
+ ProgressDatabaseFullDialogFragment.newInstance(oldestCheckpointExplorationTitle)
+ dialogFragment.showNow(
+ activity.supportFragmentManager,
+ TAG_PROGRESS_DATABASE_FULL_DIALOG
+ )
+ }
+
+ private fun showUnsavedExplorationDialogFragment() {
+ val previousFragment =
+ activity.supportFragmentManager.findFragmentByTag(TAG_UNSAVED_EXPLORATION_DIALOG)
+ if (previousFragment != null) {
+ activity.supportFragmentManager.beginTransaction().remove(previousFragment).commitNow()
+ }
+ val dialogFragment = UnsavedExplorationDialogFragment.newInstance()
+ dialogFragment.showNow(
+ activity.supportFragmentManager,
+ TAG_UNSAVED_EXPLORATION_DIALOG
+ )
+ }
+
+ /**
+ * Listens to the result of [ExplorationDataController.getOldestExplorationDetailsDataProvider].
+ *
+ * If the result is success it updates the value of the variables oldestCheckpointExplorationId
+ * and oldestCheckpointExplorationTitle. If the result fails, it does not initializes the
+ * variables oldestCheckpointExplorationId and oldestCheckpointExplorationTitle with any value.
+ *
+ * Since this function is kicked off before any other save operation, therefore it is expected
+ * to complete before any following save operation completes.
+ *
+ * If operations fails or this function does not get enough time to complete, user is not blocked
+ * instead the flow of the application proceeds as if the checkpoints were not found. In that case,
+ * the variables oldestCheckpointExplorationId and oldestCheckpointExplorationTitle are not
+ * initialized and they remain uninitialized.
+ */
+ private fun subscribeToOldestSavedExplorationDetails() {
+ explorationDataController.getOldestExplorationDetailsDataProvider(
+ ProfileId.newBuilder().setInternalId(internalProfileId).build()
+ ).toLiveData().observe(
+ activity,
+ Observer {
+ if (it.isSuccess()) {
+ oldestCheckpointExplorationId = it.getOrThrow().explorationId
+ oldestCheckpointExplorationTitle = it.getOrThrow().explorationTitle
+ } else if (it.isFailure()) {
+ oppiaLogger.e(
+ "ExplorationActivity",
+ "Failed to retrieve oldest saved checkpoint details.",
+ it.getErrorOrNull()
+ )
+ }
+ }
+ )
+ }
+
+ /**
+ * Checks the checkpointState for the current exploration and shows an appropriate dialog
+ * fragment.
+ *
+ * If the checkpointState is equal to CHECKPOINT_SAVED_DATABASE_NOT_EXCEEDED_LIMIT,
+ * exploration will be stopped without showing any dialogFragment. If the checkpointState is equal
+ * to CHECKPOINT_SAVED_DATABASE_EXCEEDED_LIMIT, [ProgressDatabaseFullDialogFragment] will be
+ * displayed to the user. Otherwise, the dialog fragment [UnsavedExplorationDialogFragment] will
+ * be displayed to the user.
+ */
+ private fun showDialogFragmentBasedOnCurrentCheckpointState() {
+ val checkpointState = getExplorationFragment()?.getExplorationCheckpointState()
+
+ // Show UnsavedExplorationDialogFragment if checkpoint state could not be retrieved.
+ if (checkpointState == null) {
+ showUnsavedExplorationDialogFragment()
+ } else {
+ when (checkpointState) {
+ CheckpointState.CHECKPOINT_SAVED_DATABASE_NOT_EXCEEDED_LIMIT -> {
+ stopExploration()
+ }
+ CheckpointState.CHECKPOINT_SAVED_DATABASE_EXCEEDED_LIMIT -> {
+ showProgressDatabaseFullDialogFragment()
+ }
+ else -> showUnsavedExplorationDialogFragment()
+ }
+ }
+ }
 }

app/src/main/java/org/oppia/android/app/player/state/StateFragmentPresenter.kt

@@ -32,7 +32,7 @@ import org.oppia.android.app.player.state.ConfettiConfig.LARGE_CONFETTI_BURST
 import org.oppia.android.app.player.state.ConfettiConfig.MEDIUM_CONFETTI_BURST
 import org.oppia.android.app.player.state.ConfettiConfig.MINI_CONFETTI_BURST
 import org.oppia.android.app.player.state.listener.RouteToHintsAndSolutionListener
-import org.oppia.android.app.player.stopplaying.StopStatePlayingSessionListener
+import org.oppia.android.app.player.stopplaying.StopStatePlayingSessionWithSavedProgressListener
 import org.oppia.android.app.topic.conceptcard.ConceptCardFragment.Companion.CONCEPT_CARD_DIALOG_FRAGMENT_TAG
 import org.oppia.android.app.utility.SplitScreenManager
 import org.oppia.android.app.viewmodel.ViewModelProvider
@@ -179,7 +179,8 @@ class StateFragmentPresenter @Inject constructor(
  fun onReturnToTopicButtonClicked() {
  hideKeyboard()
  markExplorationCompleted()
- (activity as StopStatePlayingSessionListener).stopSession()
+ (activity as StopStatePlayingSessionWithSavedProgressListener)
+ .deleteCurrentProgressAndStopSession()
  }
 
  private fun showOrHideAudioByState(state: State) {