Fix #5981: Option Screen goes blank when user select the preferred audio language as Hindi (#6012)

<!-- READ ME FIRST: Please fill in the explanation section below and
check off every point from the Essential Checklist! -->
## Explanation
Fix #5981

The current implementation of the Audio Langauge Selection UI relies on
the `AudioLanguage` enum to display a list of ausio langauges. This is
problematic because some audio languages are not supported in prod.

This PR changes the supported audio languages list to be displayed to be
derived from the supported `OppiaLanguage`s list. This means that the
list will vary for dev or prod depending on the definitions in
`supported_languages.textproto`.

An in-place migration has also been added in `TranslationController` to
help users who had previously selected a language that is now
unsupported due to configuration changes, recover gracefully.

## Essential Checklist
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this PR fixes part of an issue, prefix the title with "Fix part of
#bugnum: ...".)
- [x] Any changes to
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files have their rationale included in the PR explanation.
- [x] The PR follows the [style
guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android
Studio
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#undo-unnecessary-changes)).
- [x] The PR is made from a branch that's **not** called "develop" and
is up-to-date with "develop".
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## For UI-specific PRs only
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changes. -->
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- Add screenshots for portrait/landscape for both a tablet & phone of
the before & after UI changes
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(RTL) screenshots (see [RTL
guide](https://github.com/oppia/oppia-android/wiki/RTL-Guidelines))
- Add a video showing the full UX flow with a screen reader enabled (see
[accessibility
guide](https://github.com/oppia/oppia-android/wiki/Accessibility-A11y-Guide))
- For PRs introducing new UI elements or color changes, both light and
dark mode screenshots must be included
- Add a screenshot demonstrating that you ran affected Espresso tests
locally & that they're passing

|Before|After|
|---|---|

|https://github.com/user-attachments/assets/f69cb01b-2bf6-4b97-9990-97e0d3348b9b|
https://github.com/user-attachments/assets/fce3e8d7-61d7-49d3-8ea2-2271bc5900c9|

Author: adhiamboperes

app/src/main/java/org/oppia/android/app/onboarding/AudioLanguageFragmentPresenter.kt

@@ -175,7 +175,10 @@ class AudioLanguageFragmentPresenter @Inject constructor(
         when (result) {
           is AsyncResult.Success -> {
             if (parentScreen == ParentScreen.OPTIONS_SCREEN) {
-              updateAudioLanguage(getAudioLanguageFromOppiaLanguage(selectedLanguage))
+              updateAudioLanguage(
+                audioLanguageSelectionViewModel
+                  .getAudioLanguageFromOppiaLanguage(selectedLanguage)
+              )
             }
           }
           is AsyncResult.Failure ->
@@ -199,18 +202,6 @@ class AudioLanguageFragmentPresenter @Inject constructor(
     }
   }
 
-  private fun getAudioLanguageFromOppiaLanguage(oppiaLanguage: OppiaLanguage): AudioLanguage {
-    return when (oppiaLanguage) {
-      OppiaLanguage.UNRECOGNIZED, OppiaLanguage.LANGUAGE_UNSPECIFIED, OppiaLanguage.HINGLISH,
-      OppiaLanguage.PORTUGUESE, OppiaLanguage.SWAHILI -> AudioLanguage.AUDIO_LANGUAGE_UNSPECIFIED
-      OppiaLanguage.ARABIC -> AudioLanguage.ARABIC_LANGUAGE
-      OppiaLanguage.ENGLISH -> AudioLanguage.ENGLISH_AUDIO_LANGUAGE
-      OppiaLanguage.HINDI -> AudioLanguage.HINDI_AUDIO_LANGUAGE
-      OppiaLanguage.BRAZILIAN_PORTUGUESE -> AudioLanguage.BRAZILIAN_PORTUGUESE_LANGUAGE
-      OppiaLanguage.NIGERIAN_PIDGIN -> AudioLanguage.NIGERIAN_PIDGIN_LANGUAGE
-    }
-  }
-
   private fun hideNavigationViews(parentScreen: ParentScreen) {
     if (parentScreen == ParentScreen.OPTIONS_SCREEN) {
       binding.onboardingStepsCount?.visibility = View.GONE

app/src/main/java/org/oppia/android/app/options/AudioLanguageFragmentPresenterV1.kt

@@ -33,6 +33,7 @@ class AudioLanguageFragmentPresenterV1 @Inject constructor(
       audioLanguageSelectionViewModel.selectedLanguage.value = audioLanguage
       audioLanguageRecyclerView.apply {
         viewModel = audioLanguageSelectionViewModel
+        lifecycleOwner = fragment
         adapter = createRecyclerViewAdapter()
       }
     }.root

app/src/main/java/org/oppia/android/app/options/AudioLanguageSelectionViewModel.kt

@@ -52,22 +52,13 @@ class AudioLanguageSelectionViewModel @Inject constructor(
   /** The [AudioLanguage] currently selected in the radio button list. */
   val selectedLanguage = MutableLiveData<AudioLanguage>()
 
-  /** The list of [AudioLanguageItemViewModel]s which can be bound to a recycler view. */
-  val recyclerViewAudioLanguageList: List<AudioLanguageItemViewModel> by lazy {
-    val languages = AudioLanguage.values().filter { it !in IGNORED_AUDIO_LANGUAGES }
-    val sortedLanguages = languages.sortedWith(
-      compareBy<AudioLanguage> { it != AudioLanguage.ENGLISH_AUDIO_LANGUAGE }
-        .thenBy { appLanguageResourceHandler.computeLocalizedDisplayName(it) }
-    )
-    sortedLanguages.map(::createItemViewModel)
-  }
-
   /** Sets the list of audio languages supported by the app based on [OppiaLanguage]. */
-  val supportedOppiaLanguagesLiveData: LiveData<List<OppiaLanguage>> by lazy {
+  // TODO(#6020): Replace getSupportedAppLanguages with an audio languages specific API.
+  val supportedOppiaLanguagesLiveData: LiveData<List<OppiaLanguage>> =
     Transformations.map(
       translationController.getSupportedAppLanguages().toLiveData()
     ) { supportedLanguagesResult ->
-      return@map when (supportedLanguagesResult) {
+      when (supportedLanguagesResult) {
         is AsyncResult.Failure -> {
           oppiaLogger.e(
             "AudioLanguageFragment",
@@ -80,7 +71,22 @@ class AudioLanguageSelectionViewModel @Inject constructor(
         is AsyncResult.Success -> supportedLanguagesResult.value
       }
     }
-  }
+
+  /** The list of [AudioLanguageItemViewModel]s which can be bound to a recycler view. */
+  val recyclerViewAudioLanguageList: LiveData<List<AudioLanguageItemViewModel>> =
+    Transformations.map(supportedOppiaLanguagesLiveData) { languages ->
+      // Order starting with English in the list, then alphabetically by the localized name of the
+      // language to match what is done by the Android OS.
+      val sortedLanguages = languages.sortedWith(
+        compareBy<OppiaLanguage> { it != OppiaLanguage.ENGLISH }
+          .thenBy { appLanguageResourceHandler.computeLocalizedDisplayName(it) }
+      )
+
+      sortedLanguages
+        .map(::getAudioLanguageFromOppiaLanguage)
+        .filter { it !in IGNORED_AUDIO_LANGUAGES }
+        .map(::createItemViewModel)
+    }
 
   private val languagePreselectionProvider: DataProvider<OppiaLanguage> by lazy {
     translationController.getAudioLanguagePreselection(profileId)
@@ -91,6 +97,19 @@ class AudioLanguageSelectionViewModel @Inject constructor(
     this.profileId = profileId
   }
 
+  /** Maps an [OppiaLanguage] to an [AudioLanguage]. */
+  fun getAudioLanguageFromOppiaLanguage(oppiaLanguage: OppiaLanguage): AudioLanguage {
+    return when (oppiaLanguage) {
+      OppiaLanguage.UNRECOGNIZED, OppiaLanguage.LANGUAGE_UNSPECIFIED, OppiaLanguage.HINGLISH,
+      OppiaLanguage.PORTUGUESE, OppiaLanguage.SWAHILI -> AudioLanguage.AUDIO_LANGUAGE_UNSPECIFIED
+      OppiaLanguage.ARABIC -> AudioLanguage.ARABIC_LANGUAGE
+      OppiaLanguage.ENGLISH -> AudioLanguage.ENGLISH_AUDIO_LANGUAGE
+      OppiaLanguage.HINDI -> AudioLanguage.HINDI_AUDIO_LANGUAGE
+      OppiaLanguage.BRAZILIAN_PORTUGUESE -> AudioLanguage.BRAZILIAN_PORTUGUESE_LANGUAGE
+      OppiaLanguage.NIGERIAN_PIDGIN -> AudioLanguage.NIGERIAN_PIDGIN_LANGUAGE
+    }
+  }
+
   private fun createItemViewModel(language: AudioLanguage): AudioLanguageItemViewModel {
     return AudioLanguageItemViewModel(
       language,

app/src/main/res/layout-sw600dp/audio_language_fragment.xml

@@ -18,5 +18,5 @@
     android:paddingBottom="@dimen/audio_language_recycler_view_padding_bottom"
     android:scrollbars="none"
     app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
-    app:list="@{viewModel.recyclerViewAudioLanguageList}" />
+    app:data="@{viewModel.recyclerViewAudioLanguageList}" />
 </layout>

app/src/main/res/layout/audio_language_fragment.xml

@@ -22,7 +22,7 @@
       android:paddingBottom="@dimen/audio_language_recycler_view_padding_bottom"
       android:scrollbars="none"
       app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
-      app:list="@{viewModel.recyclerViewAudioLanguageList}" />
+      app:data="@{viewModel.recyclerViewAudioLanguageList}" />
 
     <View
       android:id="@+id/toolbar_shadow_view"

app/src/sharedTest/java/org/oppia/android/app/options/AudioLanguageFragmentTest.kt

@@ -133,6 +133,8 @@ import javax.inject.Singleton
 @LooperMode(LooperMode.Mode.PAUSED)
 @Config(application = AudioLanguageFragmentTest.TestApplication::class)
 class AudioLanguageFragmentTest {
+  // TODO(#6022): Add tests for validating that when an unsupported language was previously
+  //  selected, it goes back to English
   private companion object {
     private const val ENGLISH_BUTTON_INDEX = 0
     private const val NIGERIAN_PIDGIN_BUTTON_INDEX = 1

domain/src/main/java/org/oppia/android/domain/translation/TranslationController.kt

@@ -3,6 +3,7 @@ package org.oppia.android.domain.translation
 import com.google.protobuf.MessageLite
 import org.oppia.android.app.model.AppLanguageSelection
 import org.oppia.android.app.model.AudioTranslationLanguageSelection
+import org.oppia.android.app.model.AudioTranslationLanguageSelection.SelectionTypeCase
 import org.oppia.android.app.model.LanguageSupportDefinition
 import org.oppia.android.app.model.LanguageSupportDefinition.LanguageId.LanguageTypeCase.IETF_BCP47_ID
 import org.oppia.android.app.model.LanguageSupportDefinition.LanguageId.LanguageTypeCase.LANGUAGETYPE_NOT_SET
@@ -51,6 +52,7 @@ private const val AUDIO_TRANSLATION_CONTENT_LANG_RES_DATA_PROVIDER_ID =
   "audio_translation_content_language_resolution"
 private const val AUDIO_TRANSLATION_CONTENT_SELECTION_DATA_PROVIDER_ID =
   "audio_translation_content_selection"
+private const val SUPPORTED_AUDIO_LANGUAGES_DATA_PROVIDER_ID = "supported_audio_languages"
 private const val UPDATE_AUDIO_TRANSLATION_CONTENT_DATA_PROVIDER_ID =
   "update_audio_translation_content"
 private const val PROFILE_AUDIO_LANGUAGE_PROVIDER_ID = "profile_audio_language"
@@ -295,12 +297,29 @@ class TranslationController @Inject constructor(
   fun getAudioTranslationContentLocale(
     profileId: ProfileId
   ): DataProvider<OppiaLocale.ContentLocale> {
+    // TODO(#6020): Replace getSupportedAppLanguages with an audio languages specific API.
     val resolvedLanguageProvider =
       getAudioTranslationContentLanguageSelection(profileId).combineWith(
-        getAppLanguageSelection(profileId), AUDIO_TRANSLATION_CONTENT_LANG_RES_DATA_PROVIDER_ID
-      ) { audioLanguageSelection, appLanguageSelection ->
-        computeAudioTranslationContentLanguage(appLanguageSelection, audioLanguageSelection)
+        getSupportedAppLanguages(), SUPPORTED_AUDIO_LANGUAGES_DATA_PROVIDER_ID
+      ) { audioLanguageSelection, supportedAppLanguages ->
+        // Before a profile sets an audio language, LANGUAGE_UNSPECIFIED is always returned.
+        // In some cases, a language might not be supported but has a fallback configured.
+        if (audioLanguageSelection.selectedLanguage in supportedAppLanguages ||
+          audioLanguageSelection.selectionTypeCase == SelectionTypeCase.USE_APP_LANGUAGE ||
+          audioLanguageSelection.selectedLanguage == OppiaLanguage.LANGUAGE_UNSPECIFIED
+        ) {
+          audioLanguageSelection
+        } else {
+          AudioTranslationLanguageSelection.newBuilder()
+            .setSelectedLanguage(OppiaLanguage.ENGLISH)
+            .build()
+        }
       }
+        .combineWith(
+          getAppLanguageSelection(profileId), AUDIO_TRANSLATION_CONTENT_LANG_RES_DATA_PROVIDER_ID
+        ) { audioLanguageSelection, appLanguageSelection ->
+          computeAudioTranslationContentLanguage(appLanguageSelection, audioLanguageSelection)
+        }
     return getSystemLanguage().combineWithAsync(
       resolvedLanguageProvider, AUDIO_TRANSLATION_CONTENT_LOCALE_DATA_PROVIDER_ID
     ) { systemLanguage, resolutionStatus ->
@@ -435,10 +454,9 @@ class TranslationController @Inject constructor(
     audioLanguageSelection: AudioTranslationLanguageSelection
   ): LanguageResolutionStatus {
     return when (audioLanguageSelection.selectionTypeCase) {
-      AudioTranslationLanguageSelection.SelectionTypeCase.SELECTED_LANGUAGE ->
+      SelectionTypeCase.SELECTED_LANGUAGE ->
         LanguageResolutionStatus.Resolved(audioLanguageSelection.selectedLanguage)
-      AudioTranslationLanguageSelection.SelectionTypeCase.USE_APP_LANGUAGE,
-      AudioTranslationLanguageSelection.SelectionTypeCase.SELECTIONTYPE_NOT_SET, null ->
+      SelectionTypeCase.USE_APP_LANGUAGE, SelectionTypeCase.SELECTIONTYPE_NOT_SET, null ->
         computeAppLanguage(appLanguageSelection)
     }
   }

domain/src/test/java/org/oppia/android/domain/translation/TranslationControllerTest.kt

@@ -25,6 +25,7 @@ import org.oppia.android.app.model.OppiaLanguage.ARABIC
 import org.oppia.android.app.model.OppiaLanguage.BRAZILIAN_PORTUGUESE
 import org.oppia.android.app.model.OppiaLanguage.ENGLISH
 import org.oppia.android.app.model.OppiaLanguage.HINDI
+import org.oppia.android.app.model.OppiaLanguage.HINGLISH
 import org.oppia.android.app.model.OppiaLanguage.LANGUAGE_UNSPECIFIED
 import org.oppia.android.app.model.OppiaLanguage.NIGERIAN_PIDGIN
 import org.oppia.android.app.model.OppiaLanguage.PORTUGUESE
@@ -1149,6 +1150,21 @@ class TranslationControllerTest {
     assertThat(context.regionDefinition.region).isEqualTo(BRAZIL)
   }
 
+  @Test
+  fun testGetAudioLocale_updateLanguageToHinglish_returnsEnglishLocale() {
+    forceDefaultLocale(Locale.ROOT)
+    ensureAudioTranslationsLanguageIsUpdatedTo(PROFILE_ID_0, HINGLISH)
+
+    val localeProvider = translationController.getAudioTranslationContentLocale(PROFILE_ID_0)
+
+    val locale = monitorFactory.waitForNextSuccessfulResult(localeProvider)
+    val context = locale.localeContext
+    assertThat(context.usageMode).isEqualTo(AUDIO_TRANSLATIONS)
+    assertThat(context.languageDefinition.language).isEqualTo(ENGLISH)
+    // This region comes from the default locale.
+    assertThat(context.regionDefinition.region).isEqualTo(REGION_UNSPECIFIED)
+  }
+
   @Test
   fun testGetAudioLocale_updateLanguageToUseApp_returnsAppLanguage() {
     // First, initialize the language to Hindi before overwriting to use the app language.