Change app language flow to use Either type

mail-settings/data/src/main/kotlin/ch/protonmail/android/mailsettings/data/repository/AppLanguageRepositoryImpl.kt

@@ -20,6 +20,9 @@ package ch.protonmail.android.mailsettings.data.repository
 
 import androidx.appcompat.app.AppCompatDelegate
 import androidx.core.os.LocaleListCompat
+import arrow.core.Either
+import arrow.core.raise.either
+import ch.protonmail.android.mailcommon.domain.model.PreferencesError
 import ch.protonmail.android.mailcommon.domain.repository.AppLocaleRepository
 import ch.protonmail.android.mailsettings.domain.model.AppLanguage
 import ch.protonmail.android.mailsettings.domain.repository.AppLanguageRepository
@@ -30,31 +33,43 @@ import javax.inject.Inject
 class AppLanguageRepositoryImpl @Inject constructor(private val appLocaleRepository: AppLocaleRepository) :
     AppLanguageRepository {
 
-    private val languagePreferenceFlow = MutableSharedFlow<AppLanguage?>(replay = 1)
+    private val languagePreferenceFlow = MutableSharedFlow<Either<PreferencesError, AppLanguage?>>(replay = 1)
 
-    override fun observe(): Flow<AppLanguage?> {
-        val savedAppLocales = AppCompatDelegate.getApplicationLocales()
-        val languageTag = savedAppLocales[0]?.toLanguageTag()
+    init {
+        val result = either<PreferencesError, AppLanguage?> {
+            val savedAppLocales = AppCompatDelegate.getApplicationLocales()
+            val languageTag = savedAppLocales[0]?.toLanguageTag()
+            val appLanguage = AppLanguage.fromTag(languageTag)
+            appLanguage
+        }.mapLeft { _ -> PreferencesError }
 
-        languagePreferenceFlow.tryEmit(AppLanguage.fromTag(languageTag))
+        languagePreferenceFlow.tryEmit(result)
+    }
 
+    override fun observe(): Flow<Either<PreferencesError, AppLanguage?>> {
         return languagePreferenceFlow
     }
 
     override fun save(language: AppLanguage) {
         val locales = LocaleListCompat.forLanguageTags(language.langTag)
         AppCompatDelegate.setApplicationLocales(locales)
-        languagePreferenceFlow.tryEmit(language)
+        val result = either<PreferencesError, AppLanguage?> {
+            language
+        }.mapLeft { _ -> PreferencesError }
 
+        languagePreferenceFlow.tryEmit(result)
         appLocaleRepository.refresh()
     }
 
     override fun clear() {
         val emptyLocales = LocaleListCompat.getEmptyLocaleList()
         AppCompatDelegate.setApplicationLocales(emptyLocales)
-        languagePreferenceFlow.tryEmit(null)
 
+        val result = either<PreferencesError, AppLanguage?> {
+            null
+        }.mapLeft { _ -> PreferencesError }
+
+        languagePreferenceFlow.tryEmit(result)
         appLocaleRepository.refresh()
     }
-
-}
+}

mail-settings/domain/src/main/kotlin/ch/protonmail/android/mailsettings/domain/model/AppLanguage.kt

@@ -48,7 +48,7 @@ enum class AppLanguage(val langName: String, val langTag: String) {
     UKRAINIAN("Українська", "uk");
 
     companion object {
-        private val map = values().associateBy { it.langTag }
+        private val map = entries.associateBy { it.langTag }
         fun fromTag(tag: String?): AppLanguage? = map[tag]
     }
 }

mail-settings/domain/src/main/kotlin/ch/protonmail/android/mailsettings/domain/repository/AppLanguageRepository.kt

@@ -18,11 +18,13 @@
 
 package ch.protonmail.android.mailsettings.domain.repository
 
+import arrow.core.Either
+import ch.protonmail.android.mailcommon.domain.model.PreferencesError
 import ch.protonmail.android.mailsettings.domain.model.AppLanguage
 import kotlinx.coroutines.flow.Flow
 
 interface AppLanguageRepository {
-    fun observe(): Flow<AppLanguage?>
+    fun observe(): Flow<Either<PreferencesError, AppLanguage?>>
     fun save(language: AppLanguage)
     fun clear()
 }

mail-settings/domain/src/main/kotlin/ch/protonmail/android/mailsettings/domain/usecase/ObserveAppSettings.kt

@@ -45,14 +45,15 @@ class ObserveAppSettings @Inject constructor(
         appLanguageRepository.observe(),
         combinedContactsRepository.observe()
     ) { autoLockPref, alternativeRouting, customLanguage, combinedContacts ->
-        val hasAutoLock = autoLockPref.getOrElse { AutoLockPreference(isEnabled = false) }
+        val hasAutoLock = autoLockPref.getOrElse { AutoLockPreference(isEnabled = false) }.isEnabled
         val hasCombinedContacts = (combinedContacts as Either.Right<CombinedContactsPreference>).value.isEnabled
         val hasAlternativeRouting = (alternativeRouting as Either.Right<AlternativeRoutingPreference>).value.isEnabled
+        val customAppLanguage = customLanguage.getOrElse { null }?.langName
 
         AppSettings(
-            hasAutoLock = hasAutoLock.isEnabled,
+            hasAutoLock = hasAutoLock,
             hasAlternativeRouting = hasAlternativeRouting,
-            customAppLanguage = customLanguage?.langName,
+            customAppLanguage = customAppLanguage,
             hasCombinedContacts = hasCombinedContacts
         )
     }

mail-settings/presentation/src/main/kotlin/ch/protonmail/android/mailsettings/presentation/settings/language/LanguageSettingsState.kt

@@ -27,7 +27,7 @@ sealed class LanguageSettingsState {
         val languages: List<LanguageUiModel>
     ) : LanguageSettingsState()
 
-    object Loading : LanguageSettingsState()
+    data object Loading : LanguageSettingsState()
 }
 
 data class LanguageUiModel(

mail-settings/presentation/src/main/kotlin/ch/protonmail/android/mailsettings/presentation/settings/language/LanguageSettingsViewModel.kt

@@ -20,6 +20,7 @@ package ch.protonmail.android.mailsettings.presentation.settings.language
 
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
+import arrow.core.Either
 import ch.protonmail.android.mailsettings.domain.model.AppLanguage
 import ch.protonmail.android.mailsettings.domain.repository.AppLanguageRepository
 import ch.protonmail.android.mailsettings.presentation.settings.language.LanguageSettingsState.Loading
@@ -39,10 +40,19 @@ class LanguageSettingsViewModel @Inject constructor(
 
     val state: Flow<LanguageSettingsState> = languageRepository
         .observe()
-        .mapLatest { selectedLang ->
-            val languages = getAppLanguageUiModels(selectedLang).sortedBy { it.name }
-            val isSystemDefault = selectedLang == null
-            LanguageSettingsState.Data(isSystemDefault, languages)
+        .mapLatest { either ->
+            when (either) {
+                is Either.Right -> {
+                    val selectedLang = either.value
+                    val languages = getAppLanguageUiModels(selectedLang).sortedBy { it.name }
+                    val isSystemDefault = selectedLang == null
+                    LanguageSettingsState.Data(isSystemDefault, languages)
+                }
+                is Either.Left -> {
+                    val defaultLanguages = getAppLanguageUiModels(null).sortedBy { it.name }
+                    LanguageSettingsState.Data(isSystemDefault = true, languages = defaultLanguages)
+                }
+            }
         }
         .stateIn(
             viewModelScope,
@@ -58,7 +68,7 @@ class LanguageSettingsViewModel @Inject constructor(
         languageRepository.clear()
     }
 
-    private fun getAppLanguageUiModels(selectedAppLanguage: AppLanguage?) = AppLanguage.values().map {
+    private fun getAppLanguageUiModels(selectedAppLanguage: AppLanguage?) = AppLanguage.entries.map {
         LanguageUiModel(
             language = it,
             isSelected = it == selectedAppLanguage,