feat(sml): create an extended UserSetting integer ValueSelector

The new `USMLIntValueSelector` extends the existing `UFGUserSetting_IntSelector` adding the ability
for users to specify an enum to auto populate the values.

Author: RebeccaStevens

Mods/SML/Config/AccessTransformers.ini

@@ -5,5 +5,6 @@ Friend=(Class="UFGUserSetting", FriendClass="USMLSessionSetting")
 Friend=(Class="UFGUnlockScannableObject", FriendClass="UModContentRegistry")
 Friend=(Class="AFGSchematicManager", FriendClass="UModContentRegistry")
 Friend=(Class="UFGResearchTreeProgressionDependency", FriendClass="UModContentRegistry")
+Friend=(Class="UFGUserSetting_IntSelector", FriendClass="USMLIntValueSelector")
 ; CSS populates this at build time (presumably with CachePlaylistSongDurations) but we don't have an implementation - make editable so it can be set manually. See GH Issue #372
 EditAnywhere=(Class="/Script/FactoryGame.SongData", Property="CachedMaximumSongDuration")

Mods/SML/Source/SML/Public/Settings/SMLIntValueSelector.h

@@ -0,0 +1,76 @@
+#pragma once
+
+#include "Algo/Reverse.h"
+#include "CoreMinimal.h"
+#include "Settings/FGUserSetting.h"
+
+#include "SMLIntValueSelector.generated.h"
+
+UCLASS(Blueprintable,
+       DefaultToInstanced,
+       EditInlineNew,
+       AutoExpandCategories = "Value",
+       meta = (DisplayName = "Integer Selector (Extended)"))
+class SML_API USMLIntValueSelector : public UFGUserSetting_IntSelector {
+  GENERATED_BODY()
+
+#if WITH_EDITORONLY_DATA
+ protected:
+  /**
+   * Auto populate the integer selection values from this enum class's values.
+   */
+  UPROPERTY(BlueprintReadOnly, EditDefaultsOnly, Category = "Value")
+  class UEnum* EnumClass;
+
+  /**
+   * If true, the enum values will be displayed in reverse order.
+   */
+  UPROPERTY(BlueprintReadOnly,
+            EditDefaultsOnly,
+            Category = "Value",
+            meta = (EditCondition = "EnumClass != nullptr", EditConditionHides))
+  bool bReverseEnumOrder;
+
+  void PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent) {
+    Super::PostEditChangeProperty(PropertyChangedEvent);
+    if (PropertyChangedEvent.GetPropertyName() == GET_MEMBER_NAME_CHECKED(USMLIntValueSelector, EnumClass) ||
+        PropertyChangedEvent.GetPropertyName() == GET_MEMBER_NAME_CHECKED(USMLIntValueSelector, bReverseEnumOrder)) {
+      PopulateIntegerSelectionValues();
+    }
+  }
+
+ private:
+  void PopulateIntegerSelectionValues() {
+    if (EnumClass == nullptr) {
+      // Don't auto empty the values - the user may still want them.
+      return;
+    }
+    IntegerSelectionValues.Empty();
+    int32 EnumCount = EnumClass->ContainsExistingMax() ? EnumClass->NumEnums() - 1 : EnumClass->NumEnums();
+    IntegerSelectionValues.Reserve(EnumCount);
+    for (int32 EnumIndex = 0; EnumIndex < EnumCount; ++EnumIndex) {
+      IntegerSelectionValues.Add(FIntegerSelection(EnumClass->GetDisplayNameTextByIndex(EnumIndex), EnumIndex));
+    }
+    if (bReverseEnumOrder) {
+      Algo::Reverse(IntegerSelectionValues);
+    }
+  }
+#endif
+
+#if WITH_EDITOR
+ protected:
+  bool CanEditChange(const FProperty* InProperty) const override {
+    const bool ParentVal = Super::CanEditChange(InProperty);
+    if (!ParentVal) {
+      return false;
+    }
+
+    if (InProperty->GetFName() == GET_MEMBER_NAME_CHECKED(USMLIntValueSelector, IntegerSelectionValues)) {
+      // Allow editing when the enum class is null.
+      return EnumClass == nullptr;
+    }
+
+    return true;
+  }
+#endif
+};