Bug 1884390 - Adjust Unsupported Error in Translations

This patch:
* Adds an option in `LocaleUtils` to fetch language names for a given locale.
* Adjusts Translations Unsupported Error to use this option.

app/src/main/java/org/mozilla/fenix/translations/TranslationsDialogBinding.kt

@@ -15,6 +15,7 @@ import mozilla.components.browser.state.store.BrowserStore
 import mozilla.components.concept.engine.translate.initialFromLanguage
 import mozilla.components.concept.engine.translate.initialToLanguage
 import mozilla.components.lib.state.helpers.AbstractBinding
+import mozilla.components.support.locale.LocaleManager
 import org.mozilla.fenix.utils.LocaleUtils
 import java.util.Locale
 
@@ -29,7 +30,7 @@ class TranslationsDialogBinding(
     private val getTranslatedPageTitle: (localizedFrom: String?, localizedTo: String?) -> String,
 ) : AbstractBinding<BrowserState>(browserStore) {
 
-    @Suppress("LongMethod")
+    @Suppress("LongMethod", "CyclomaticComplexMethod")
     override suspend fun onState(flow: Flow<BrowserState>) {
         // Browser level flows
         val browserFlow = flow.mapNotNull { state -> state }
@@ -132,11 +133,15 @@ class TranslationsDialogBinding(
 
                 // A session error may override a browser error
                 if (sessionTranslationsState.translationError != null) {
-                    var documentLangDisplayName: String? = null
-                    sessionTranslationsState.translationEngineState?.detectedLanguages?.documentLangTag?.let {
-                        val documentLanguage = Locale.forLanguageTag(it)
-                        documentLangDisplayName = LocaleUtils.getDisplayName(documentLanguage)
-                    }
+                    val documentLangDisplayName = sessionTranslationsState.translationEngineState
+                        ?.detectedLanguages?.documentLangTag?.let { docLangTag ->
+                            val documentLocale = Locale.forLanguageTag(docLangTag)
+                            val userLocale = state.browserState.locale ?: LocaleManager.getSystemDefault()
+                            LocaleUtils.getLocalizedDisplayName(
+                                userLocale = userLocale,
+                                languageLocale = documentLocale,
+                            )
+                        }
 
                     translationsDialogStore.dispatch(
                         TranslationsDialogAction.UpdateTranslationError(

app/src/main/java/org/mozilla/fenix/utils/LocaleUtils.kt

@@ -12,7 +12,14 @@ import java.util.Locale
 object LocaleUtils {
 
     /**
-     * Returns a name for the locale that is appropriate for display to the user.
+     * Returns a name for the locale that is appropriate for display to the user. The display name
+     * will be in the language of the specified locale.
+     *
+     * For example, in an any language locale, the German language locale or "de" would be
+     * presented as "Deutsch".
+     *
+     * @param locale The locale to determine a language name.
+     * @return A default title case display name in the locale's language.
      */
     fun getDisplayName(locale: Locale): String {
         val displayName = locale.getDisplayName(locale)
@@ -23,6 +30,27 @@ object LocaleUtils {
         return displayName
     }
 
+    /**
+     * Returns a name for the locale that is appropriate for display to the user based on the user's
+     * specified language.
+     *
+     * For example, in an an English language locale, the German language locale or "de" would be
+     * presented as "German".
+     *
+     * @param userLocale The locale the user is using.
+     * @param languageLocale The locale to localize the language name into the user's language.
+     *
+     * @return A default language name in the specified user's locale language.
+     */
+    fun getLocalizedDisplayName(userLocale: Locale, languageLocale: Locale): String {
+        val displayName = Locale.forLanguageTag(languageLocale.toLanguageTag()).getDisplayName(userLocale)
+        return if (userLocale == Locale.ENGLISH) {
+            LOCALE_TO_DISPLAY_ENGLISH_NAME_MAP[languageLocale.toString()] ?: displayName
+        } else {
+            displayName
+        }
+    }
+
     private val LOCALE_TO_DISPLAY_NATIVE_NAME_MAP: Map<String, String> = mapOf(
         "an" to "Aragonés",
         "anp" to "अंगिका",

app/src/test/java/org/mozilla/fenix/translations/TranslationsDialogReducerTest.kt

@@ -166,13 +166,13 @@ class TranslationsDialogReducerTest {
                 translationError = TranslationError.LanguageNotSupportedError(
                     null,
                 ),
-                documentLangDisplayName = "Deutsch",
+                documentLangDisplayName = "German",
             ),
         )
 
         assertTrue(updatedState.error is TranslationError.LanguageNotSupportedError)
         assertEquals(PositiveButtonType.Disabled, updatedState.positiveButtonType)
-        assertEquals(updatedState.documentLangDisplayName, "Deutsch")
+        assertEquals(updatedState.documentLangDisplayName, "German")
 
         val updatedStateTwo = TranslationsDialogReducer.reduce(
             translationsDialogState,

app/src/test/java/org/mozilla/fenix/utils/LocaleUtilsTest.kt

@@ -0,0 +1,32 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.fenix.utils
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mozilla.fenix.helpers.FenixRobolectricTestRunner
+import java.util.Locale
+
+@RunWith(FenixRobolectricTestRunner::class)
+class LocaleUtilsTest {
+
+    @Test
+    fun `WHEN using getDisplayName on a 'de' locale THEN get the expected default name`() {
+        val localizedLanguageName = LocaleUtils.getDisplayName(
+            locale = Locale("de"),
+        )
+        assertEquals("Deutsch", localizedLanguageName)
+    }
+
+    @Test
+    fun `WHEN using getLocalizedDisplayName with an 'en' locale on a 'de' locale THEN get the expected localized name`() {
+        val localizedLanguageName = LocaleUtils.getLocalizedDisplayName(
+            userLocale = Locale("en"),
+            languageLocale = Locale("de"),
+        )
+        assertEquals("German", localizedLanguageName)
+    }
+}