avoid creating additional subtypes that are the same as a resource subtype

app/src/main/java/helium314/keyboard/latin/settings/SettingsSubtype.kt

@@ -14,11 +14,13 @@ import helium314.keyboard.latin.utils.LayoutType.Companion.toExtraValue
 import helium314.keyboard.latin.utils.Log
 import helium314.keyboard.latin.utils.ScriptUtils
 import helium314.keyboard.latin.utils.ScriptUtils.script
+import helium314.keyboard.latin.utils.SubtypeSettings
 import helium314.keyboard.latin.utils.SubtypeUtilsAdditional
 import helium314.keyboard.latin.utils.locale
 import java.util.Locale
 
 // some kind of intermediate between the string stored in preferences and an InputMethodSubtype
+// todo: consider using a hashMap or sortedMap instead of a string if we run into comparison issues once again
 data class SettingsSubtype(val locale: Locale, val extraValues: String) {
 
     fun toPref() = locale.toLanguageTag() + Separators.SET + extraValues
@@ -70,6 +72,8 @@ data class SettingsSubtype(val locale: Locale, val extraValues: String) {
         prefs.getString(Settings.PREF_ADDITIONAL_SUBTYPES, Defaults.PREF_ADDITIONAL_SUBTYPES)!!
             .split(Separators.SETS).contains(toPref())
 
+    fun isSameAsDefault() = SubtypeSettings.getResourceSubtypesForLocale(locale).any { it.toSettingsSubtype() == this.toPref().toSettingsSubtype() }
+
     companion object {
         fun String.toSettingsSubtype(): SettingsSubtype =
             SettingsSubtype(

app/src/main/java/helium314/keyboard/latin/utils/SubtypeSettings.kt

@@ -124,6 +124,10 @@ object SubtypeSettings {
 
     fun getAvailableSubtypeLocales(): List<Locale> = resourceSubtypesByLocale.keys.toList()
 
+    /**
+     * Update subtypes that contain the layout. If new name is null (layout deleted) and the
+     * subtype is now identical to a resource subtype, remove the subtype from additional subtypes.
+     */
     fun onRenameLayout(type: LayoutType, from: String, to: String?, context: Context) {
         val prefs = context.prefs()
         listOf(
@@ -131,10 +135,19 @@ object SubtypeSettings {
             Settings.PREF_ENABLED_SUBTYPES to Defaults.PREF_ENABLED_SUBTYPES,
             Settings.PREF_SELECTED_SUBTYPE to Defaults.PREF_SELECTED_SUBTYPE
         ).forEach { (key, default) ->
-            val new = prefs.getString(key, default)!!.split(Separators.SETS).mapTo(mutableSetOf()) {
+            val new = prefs.getString(key, default)!!.split(Separators.SETS).mapNotNullTo(mutableSetOf()) {
                 val subtype = it.toSettingsSubtype()
                 if (subtype.layoutName(type) == from) {
-                    if (to == null) subtype.withoutLayout(type).toPref()
+                    if (to == null) {
+                        val defaultLayout = if (type !== LayoutType.MAIN) null
+                            // if we just delete a main layout, we may end up with something like Hindi (QWERTY)
+                            // so better replace it with a default layout for that locale
+                            else resourceSubtypesByLocale[subtype.locale]?.first()?.mainLayoutName()
+                        val newSubtype = if (defaultLayout == null) subtype.withoutLayout(type)
+                            else subtype.withLayout(type, defaultLayout)
+                        if (newSubtype.isSameAsDefault() && key == Settings.PREF_ADDITIONAL_SUBTYPES) null
+                        else subtype.withoutLayout(type).toPref()
+                    }
                     else subtype.withLayout(type, to).toPref()
                 }
                 else subtype.toPref()

app/src/main/java/helium314/keyboard/latin/utils/SubtypeUtilsAdditional.kt

@@ -70,7 +70,7 @@ object SubtypeUtilsAdditional {
         val additionalSubtypes = SubtypeSettings.createSettingsSubtypes(prefs.getString(Settings.PREF_ADDITIONAL_SUBTYPES, Defaults.PREF_ADDITIONAL_SUBTYPES)!!)
             .toMutableList()
         additionalSubtypes.remove(from)
-        if (SubtypeSettings.getResourceSubtypesForLocale(to.locale).none { it.toSettingsSubtype() == to }) {
+        if (!to.isSameAsDefault()) {
             // We only add the "to" subtype if it's not equal to a resource subtype.
             // This means we make additional subtype disappear as magically as it was added if all settings are default.
             // If we don't do this, enabling the base subtype will result in the additional subtype being enabled,

app/src/main/java/helium314/keyboard/settings/screens/SubtypeScreen.kt

@@ -388,8 +388,13 @@ private fun MainLayoutRow(
                     title = { Text(stringResource(R.string.delete_layout, LayoutUtilsCustom.getDisplayName(it))) },
                     content = { if (others) Text(stringResource(R.string.layout_in_use)) },
                     onConfirmed = {
-                        if (it == currentSubtype.mainLayoutName())
+                        if (it == currentSubtype.mainLayoutName()) {
-                            setCurrentSubtype(currentSubtype.withoutLayout(LayoutType.MAIN))
+                            // similar to what is done in SubtypeSettings.onRenameLayout
+                            val defaultLayout = SubtypeSettings.getResourceSubtypesForLocale(currentSubtype.locale).firstOrNull()?.mainLayoutName()
+                            val newSubtype = if (defaultLayout == null) currentSubtype.withoutLayout(LayoutType.MAIN)
+                                else currentSubtype.withLayout(LayoutType.MAIN, defaultLayout)
+                            setCurrentSubtype(newSubtype)
+                        }
                         LayoutUtilsCustom.deleteLayout(it, LayoutType.MAIN, ctx)
                         (ctx.getActivity() as? SettingsActivity)?.prefChanged()
                     }