// Copyright Epic Games, Inc. All Rights Reserved.

#include "PreviewSceneCustomizations.h"
#include "Modules/ModuleManager.h"
#include "AssetRegistry/AssetData.h"
#include "IDetailPropertyRow.h"
#include "DetailLayoutBuilder.h"
#include "DetailCategoryBuilder.h"
#include "PropertyCustomizationHelpers.h"
#include "PersonaPreviewSceneDescription.h"
#include "PersonaPreviewSceneController.h"
#include "PersonaPreviewSceneDefaultController.h"
#include "PersonaPreviewSceneRefPoseController.h"
#include "PersonaPreviewSceneAnimationController.h"
#include "Engine/PreviewMeshCollection.h"
#include "Factories/PreviewMeshCollectionFactory.h"
#include "IPropertyUtilities.h"
#include "Preferences/PersonaOptions.h"
#include "Widgets/Input/SButton.h"
#include "Widgets/Text/STextBlock.h"
#include "Widgets/Input/SCheckBox.h"
#include "Widgets/Images/SImage.h"
#include "AssetToolsModule.h"
#include "IAssetTools.h"
#include "Animation/AnimBlueprint.h"
#include "Animation/Skeleton.h"
#include "UObject/UObjectIterator.h"
#include "Widgets/Input/SComboBox.h"
#include "PhysicsEngine/PhysicsAsset.h"
#include "Algo/Sort.h"
#include "ScopedTransaction.h"
#include "Features/IModularFeatures.h"
#include "AnimPreviewInstance.h"
#include "PersonaModule.h"
#include "PersonaPreviewSceneSkelMeshInstanceController.h"

#define LOCTEXT_NAMESPACE "PreviewSceneCustomizations"

// static list that contains available classes, so that we can only allow these classes
TArray<FTopLevelAssetPath> FPreviewSceneDescriptionCustomization::AvailableClassNameList;

FPreviewSceneDescriptionCustomization::FPreviewSceneDescriptionCustomization(const FString& InSkeletonName, const TSharedRef<class IPersonaToolkit>& InPersonaToolkit)
	: SkeletonName(InSkeletonName)
	, PersonaToolkit(InPersonaToolkit)
	, PreviewScene(StaticCastSharedRef<FAnimationEditorPreviewScene>(InPersonaToolkit->GetPreviewScene()))
	, EditableSkeleton(InPersonaToolkit->GetEditableSkeleton())
{
	// setup custom factory up-front so we can control its lifetime
	FactoryToUse = NewObject<UPreviewMeshCollectionFactory>();
	FactoryToUse->AddToRoot();

	// only first time
	if (AvailableClassNameList.Num() == 0)
	{
		for (TObjectIterator<UClass> ClassIt; ClassIt; ++ClassIt)
		{
			if (ClassIt->IsChildOf(UDataAsset::StaticClass()) && ClassIt->ImplementsInterface(UPreviewCollectionInterface::StaticClass()))
			{
				AvailableClassNameList.Add(ClassIt->GetClassPathName());
			}
		}
	}
}

FPreviewSceneDescriptionCustomization::~FPreviewSceneDescriptionCustomization()
{
	if (FactoryToUse)
	{
		FactoryToUse->RemoveFromRoot();
		FactoryToUse = nullptr;
	}

	if (const TSharedPtr<IPersonaToolkit> Toolkit = PersonaToolkit.Pin())
	{
		if (UAnimBlueprint* AnimBlueprint = Toolkit->GetAnimBlueprint())
		{
			AnimBlueprint->OnCompiled().RemoveAll(this);
		}
	}
}

void FPreviewSceneDescriptionCustomization::CustomizeDetails(IDetailLayoutBuilder& DetailBuilder)
{
	MyDetailLayout = &DetailBuilder;
	
	// allow customization by client asset editor
	PersonaToolkit.Pin()->CustomizeSceneSettings(DetailBuilder);

	// name label given to the context of this persona instance (usually the class name of the asset)
	const FName PersonaContextName = PersonaToolkit.Pin()->GetContext();

	//
	// Preview Controller section...
	//
	{
		TSharedRef<IPropertyHandle> PreviewControllerProperty = DetailBuilder.GetProperty(GET_MEMBER_NAME_CHECKED(UPersonaPreviewSceneDescription, PreviewController));
		PreviewControllerProperty->MarkHiddenByCustomization();
		
		TArray<UClass*> BuiltInPreviewControllers = {
			UPersonaPreviewSceneDefaultController::StaticClass(),
			UPersonaPreviewSceneRefPoseController::StaticClass(),
			UPersonaPreviewSceneAnimationController::StaticClass(),
			UPersonaPreviewSceneSkelMeshInstanceController::StaticClass() };
		TArray<UClass*> DynamicPreviewControllers;
		for (TObjectIterator<UClass> It; It; ++It)
		{
			UClass* CurrentClass = *It;
			if (CurrentClass->IsChildOf(UPersonaPreviewSceneController::StaticClass()) &&
				!(CurrentClass->HasAnyClassFlags(CLASS_Abstract)) &&
				!BuiltInPreviewControllers.Contains(CurrentClass))
			{
				DynamicPreviewControllers.Add(CurrentClass);
			}
		}

		Algo::SortBy(DynamicPreviewControllers, [](UClass* Cls) { return Cls->GetName(); });

		ControllerItems.Reset();
		for (UClass* ControllerClass : BuiltInPreviewControllers)
		{
			ControllerItems.Add(MakeShared<FPersonaModeComboEntry>(ControllerClass));
		}
		for (UClass* ControllerClass : DynamicPreviewControllers)
		{
			ControllerItems.Add(MakeShared<FPersonaModeComboEntry>(ControllerClass));
		}

		ControllerItems.RemoveAll([](const TSharedPtr<FPersonaModeComboEntry>& ControllerEntry)
			{
				return !GetMutableDefault<UPersonaOptions>()->IsAllowedClass(ControllerEntry->Class);
			});

		IDetailCategoryBuilder& AnimCategory = DetailBuilder.EditCategory("Animation");
		AnimCategory.AddCustomRow(PreviewControllerProperty->GetPropertyDisplayName())
		.NameContent()
		[
			PreviewControllerProperty->CreatePropertyNameWidget()
		]
		.ValueContent()
		.MinDesiredWidth(200.0f)
		[
			SNew(SComboBox<TSharedPtr<FPersonaModeComboEntry>>)
			.OptionsSource(&ControllerItems)
			.OnGenerateWidget(this, &FPreviewSceneDescriptionCustomization::MakeControllerComboEntryWidget)
			.OnSelectionChanged(this, &FPreviewSceneDescriptionCustomization::OnComboSelectionChanged)
			[
				SNew(STextBlock)
				.Text(this, &FPreviewSceneDescriptionCustomization::GetCurrentPreviewControllerText)
			]
		];

		// register PropertyValueChanged callbacks for all properties in the preview controller
		FSimpleDelegate PropertyChangedDelegate = FSimpleDelegate::CreateSP(this, &FPreviewSceneDescriptionCustomization::HandlePreviewControllerPropertyChanged);
		UPersonaPreviewSceneDescription* PersonaPreviewSceneDescription = PreviewScene.Pin()->GetPreviewSceneDescription();
		for (const FProperty* TestProperty : TFieldRange<FProperty>(PersonaPreviewSceneDescription->PreviewControllerInstance->GetClass()))
		{
			if (TestProperty->HasAnyPropertyFlags(CPF_Edit))
			{
				const bool bAdvancedDisplay = TestProperty->HasAnyPropertyFlags(CPF_AdvancedDisplay);
				const EPropertyLocation::Type PropertyLocation = bAdvancedDisplay ? EPropertyLocation::Advanced : EPropertyLocation::Common;

				IDetailPropertyRow* NewRow = PersonaPreviewSceneDescription->PreviewControllerInstance->AddPreviewControllerPropertyToDetails(PersonaToolkit.Pin().ToSharedRef(), DetailBuilder, AnimCategory, TestProperty, PropertyLocation);
				if (NewRow)
				{
					NewRow->GetPropertyHandle()->SetOnPropertyValueChanged(PropertyChangedDelegate);
				}
			}
		}
	}

	//
	// Preview Mesh section...
	//
	{
		TSharedRef<IPropertyHandle> SkeletalMeshProperty = DetailBuilder.GetProperty(GET_MEMBER_NAME_CHECKED(UPersonaPreviewSceneDescription, PreviewMesh));
		SkeletalMeshProperty->MarkHiddenByCustomization();
		
		FText PreviewMeshName;
		if (PersonaContextName == UAnimationAsset::StaticClass()->GetFName())
		{
			PreviewMeshName = FText::Format(LOCTEXT("PreviewMeshAnimation", "{0}\n(Animation)"), SkeletalMeshProperty->GetPropertyDisplayName());
		}
		else if(PersonaContextName == UAnimBlueprint::StaticClass()->GetFName())
		{
			PreviewMeshName = FText::Format(LOCTEXT("PreviewMeshAnimBlueprint", "{0}\n(Animation Blueprint)"), SkeletalMeshProperty->GetPropertyDisplayName());
		}
		else if(PersonaContextName == UPhysicsAsset::StaticClass()->GetFName())
		{
			PreviewMeshName = FText::Format(LOCTEXT("PreviewMeshPhysicsAsset", "{0}\n(Physics Asset)"), SkeletalMeshProperty->GetPropertyDisplayName());
		}
		else if(PersonaContextName == USkeleton::StaticClass()->GetFName())
		{
			PreviewMeshName = FText::Format(LOCTEXT("PreviewMeshSkeleton", "{0}\n(Skeleton)"), SkeletalMeshProperty->GetPropertyDisplayName());
		}
		else
		{
			PreviewMeshName = SkeletalMeshProperty->GetPropertyDisplayName();
		}

		const bool bCanUseDifferentSkeleton = PersonaToolkit.Pin()->CanPreviewMeshUseDifferentSkeleton();

		DetailBuilder.EditCategory("Mesh")
		.AddProperty(SkeletalMeshProperty)
		.CustomWidget()
		.OverrideResetToDefault(FResetToDefaultOverride::Create(
			TAttribute<bool>::CreateLambda([PreviewSceneWeakPtr = TWeakPtr<class FAnimationEditorPreviewScene>(PreviewScene)]()
			{
				if (PreviewSceneWeakPtr.IsValid())
				{
					return PreviewSceneWeakPtr.Pin()->GetPreviewMesh() != nullptr;
				}
				return false;
			}),
			FSimpleDelegate::CreateLambda([PreviewSceneWeakPtr = TWeakPtr<class FAnimationEditorPreviewScene>(PreviewScene)]()
			{
				if (PreviewSceneWeakPtr.IsValid())
				{
					PreviewSceneWeakPtr.Pin()->SetPreviewMesh(nullptr, false);
				}
			}))
		)
		.NameContent()
		[
			SNew(SVerticalBox)
			+SVerticalBox::Slot()
			.AutoHeight()
			[
				SkeletalMeshProperty->CreatePropertyNameWidget(PreviewMeshName)
			]
			+SVerticalBox::Slot()
			.AutoHeight()
			.HAlign(HAlign_Center)
			[
				SNew(SButton)
				.Text(LOCTEXT("ApplyToAsset", "Apply To Asset"))
				.ToolTipText(LOCTEXT("ApplyToAssetToolTip", "The preview mesh has changed, but it will not be able to be saved until it is applied to the asset. Click here to make the change to the preview mesh persistent."))
				.Visibility_Lambda([PersonaToolkitWeakPtr = TWeakPtr<class IPersonaToolkit>(PersonaToolkit)]()
				{
					if (PersonaToolkitWeakPtr.IsValid())
					{
						const TSharedPtr<IPersonaToolkit> PinnedPersonaToolkit = PersonaToolkitWeakPtr.Pin();
						USkeletalMesh* SkeletalMesh = PinnedPersonaToolkit->GetPreviewMesh();
						return (SkeletalMesh != PinnedPersonaToolkit->GetPreviewScene()->GetPreviewMesh()) ? EVisibility::Visible : EVisibility::Collapsed;
					}

					return EVisibility::Collapsed;
				})
				.OnClicked_Lambda([PersonaToolkitWeakPtr = TWeakPtr<class IPersonaToolkit>(PersonaToolkit)]()
				{
					if (PersonaToolkitWeakPtr.IsValid())
					{
						TSharedPtr<IPersonaToolkit> PinnedPersonaToolkit = PersonaToolkitWeakPtr.Pin();
						PinnedPersonaToolkit->SetPreviewMesh(PinnedPersonaToolkit->GetPreviewScene()->GetPreviewMesh(), true);
					}
					return FReply::Handled();
				})
			]
		]
		.ValueContent()
		.MaxDesiredWidth(250.0f)
		.MinDesiredWidth(250.0f)
		[
			SNew(SObjectPropertyEntryBox)
			.AllowedClass(USkeletalMesh::StaticClass())
			.PropertyHandle(SkeletalMeshProperty)
			.OnShouldFilterAsset(this, &FPreviewSceneDescriptionCustomization::HandleShouldFilterAsset, USkeletalMesh::GetSkeletonMemberName(), bCanUseDifferentSkeleton)
			.OnObjectChanged(this, &FPreviewSceneDescriptionCustomization::HandleMeshChanged)
			.ThumbnailPool(DetailBuilder.GetThumbnailPool())
		];
	}

	// Customize animation blueprint preview
	TSharedRef<IPropertyHandle> PreviewAnimationBlueprintProperty = DetailBuilder.GetProperty(GET_MEMBER_NAME_CHECKED(UPersonaPreviewSceneDescription, PreviewAnimationBlueprint));
	TSharedRef<IPropertyHandle> ApplicationMethodProperty = DetailBuilder.GetProperty(GET_MEMBER_NAME_CHECKED(UPersonaPreviewSceneDescription, ApplicationMethod));
	TSharedRef<IPropertyHandle> LinkedAnimGraphTagProperty = DetailBuilder.GetProperty(GET_MEMBER_NAME_CHECKED(UPersonaPreviewSceneDescription, LinkedAnimGraphTag));
	
	if (PersonaToolkit.Pin()->GetContext() == UAnimBlueprint::StaticClass()->GetFName())
	{
		DetailBuilder.EditCategory("Animation Blueprint")
		.AddProperty(PreviewAnimationBlueprintProperty)
		.CustomWidget()
		.NameContent()
		[
			SNew(SVerticalBox)
			+SVerticalBox::Slot()
			.AutoHeight()
			[
				PreviewAnimationBlueprintProperty->CreatePropertyNameWidget()
			]
		]
		.ValueContent()
		.MaxDesiredWidth(250.0f)
		.MinDesiredWidth(250.0f)
		[
			SNew(SObjectPropertyEntryBox)
			.AllowedClass(UAnimBlueprint::StaticClass())
			.PropertyHandle(PreviewAnimationBlueprintProperty)
			.OnShouldFilterAsset(this, &FPreviewSceneDescriptionCustomization::HandleShouldFilterAsset, FName("TargetSkeleton"), false)
			.OnObjectChanged(this, &FPreviewSceneDescriptionCustomization::HandlePreviewAnimBlueprintChanged)
			.ThumbnailPool(DetailBuilder.GetThumbnailPool())
		];

		ApplicationMethodProperty->SetOnPropertyValueChanged(FSimpleDelegate::CreateLambda([this]()
		{
			FScopedTransaction Transaction(LOCTEXT("SetAnimationBlueprintApplicationMethod", "Set Application Method"));

			TSharedPtr<IPersonaToolkit> PinnedPersonaToolkit = PersonaToolkit.Pin();
			TSharedRef<FAnimationEditorPreviewScene> LocalPreviewScene = StaticCastSharedRef<FAnimationEditorPreviewScene>(PinnedPersonaToolkit->GetPreviewScene());
			UPersonaPreviewSceneDescription* PersonaPreviewSceneDescription = LocalPreviewScene->GetPreviewSceneDescription();
			PinnedPersonaToolkit->GetAnimBlueprint()->SetPreviewAnimationBlueprintApplicationMethod(PersonaPreviewSceneDescription->ApplicationMethod);
			LocalPreviewScene->SetPreviewAnimationBlueprint(PersonaPreviewSceneDescription->PreviewAnimationBlueprint.Get(), PinnedPersonaToolkit->GetAnimBlueprint());
		}));

		DetailBuilder.EditCategory("Animation Blueprint")
		.AddProperty(ApplicationMethodProperty)
		.IsEnabled(MakeAttributeLambda([this]()
		{
			TSharedPtr<IPersonaToolkit> PinnedPersonaToolkit = PersonaToolkit.Pin();
			TSharedRef<FAnimationEditorPreviewScene> LocalPreviewScene = StaticCastSharedRef<FAnimationEditorPreviewScene>(PinnedPersonaToolkit->GetPreviewScene());
			UPersonaPreviewSceneDescription* PersonaPreviewSceneDescription = LocalPreviewScene->GetPreviewSceneDescription();
			
			return PersonaPreviewSceneDescription->PreviewAnimationBlueprint.IsValid();
		}));
	
		LinkedAnimGraphTagProperty->SetOnPropertyValueChanged(FSimpleDelegate::CreateLambda([this]()
		{
			FScopedTransaction Transaction(LOCTEXT("SetAnimationBlueprintTag", "Set Linked Anim Graph Tag"));

			TSharedPtr<IPersonaToolkit> PinnedPersonaToolkit = PersonaToolkit.Pin();
			TSharedRef<FAnimationEditorPreviewScene> LocalPreviewScene = StaticCastSharedRef<FAnimationEditorPreviewScene>(PinnedPersonaToolkit->GetPreviewScene());
			UPersonaPreviewSceneDescription* PersonaPreviewSceneDescription = LocalPreviewScene->GetPreviewSceneDescription();
			PinnedPersonaToolkit->GetAnimBlueprint()->SetPreviewAnimationBlueprintTag(PersonaPreviewSceneDescription->LinkedAnimGraphTag);
			LocalPreviewScene->SetPreviewAnimationBlueprint(PersonaPreviewSceneDescription->PreviewAnimationBlueprint.Get(), PinnedPersonaToolkit->GetAnimBlueprint());
		}));

		DetailBuilder.EditCategory("Animation Blueprint")
		.AddProperty(LinkedAnimGraphTagProperty)
		.IsEnabled(MakeAttributeLambda([this]()
		{
			TSharedPtr<IPersonaToolkit> PinnedPersonaToolkit = PersonaToolkit.Pin();
			TSharedRef<FAnimationEditorPreviewScene> LocalPreviewScene = StaticCastSharedRef<FAnimationEditorPreviewScene>(PinnedPersonaToolkit->GetPreviewScene());
			UPersonaPreviewSceneDescription* PersonaPreviewSceneDescription = LocalPreviewScene->GetPreviewSceneDescription();
			
			return PersonaPreviewSceneDescription->PreviewAnimationBlueprint.IsValid() && PersonaPreviewSceneDescription->ApplicationMethod == EPreviewAnimationBlueprintApplicationMethod::LinkedAnimGraph;
		}));
	}
	else
	{
		PreviewAnimationBlueprintProperty->MarkHiddenByCustomization();
		ApplicationMethodProperty->MarkHiddenByCustomization();
		LinkedAnimGraphTagProperty->MarkHiddenByCustomization();
	}

	//
	// Physics section...
	//
#if CHAOS_SIMULATION_DETAIL_VIEW_FACTORY_SELECTOR
	// Physics settings
	ClothSimulationFactoryList.Reset();
	const TArray<IClothingSimulationFactoryClassProvider*> ClassProviders = IModularFeatures::Get().GetModularFeatureImplementations<IClothingSimulationFactoryClassProvider>(IClothingSimulationFactoryClassProvider::FeatureName);
	for (const auto& ClassProvider : ClassProviders)
	{
		// Populate cloth factory list
		ClothSimulationFactoryList.Add(MakeShared<TSubclassOf<class UClothingSimulationFactory>>(ClassProvider->GetClothingSimulationFactoryClass()));
	}

	DetailBuilder.EditCategory("Physics")
	.AddCustomRow(LOCTEXT("PhysicsClothingSimulationFactory", "Clothing Simulation Factory Option"))
	.RowTag("PhysicsClothingSimulationFactory")
	.NameContent()
	[
		SNew(STextBlock)
		.Font(IDetailLayoutBuilder::GetDetailFont())
		.Text(LOCTEXT("PhysicsClothingSimulationFactory_Text", "Clothing Simulation Factory"))
		.ToolTipText(LOCTEXT("PhysicsClothingSimulationFactory_ToolTip", "Select the cloth simulation used to preview the scene."))
	]
	.ValueContent()
	.MinDesiredWidth(200.0f)
	[
		SNew(SComboBox<TSharedPtr<TSubclassOf<class UClothingSimulationFactory>>>)
		.OptionsSource(&ClothSimulationFactoryList)
		.OnGenerateWidget(this, &FPreviewSceneDescriptionCustomization::MakeClothingSimulationFactoryWidget)
		.OnSelectionChanged(this, &FPreviewSceneDescriptionCustomization::OnClothingSimulationFactorySelectionChanged)
		[
			SNew(STextBlock)
			.Text(this, &FPreviewSceneDescriptionCustomization::GetCurrentClothingSimulationFactoryText)
		]
	];
#endif  // #if CHAOS_SIMULATION_DETAIL_VIEW_FACTORY_SELECTOR

	//
	// Additional Meshes section...
	//
	{
		AdditionalMeshesProperty = DetailBuilder.GetProperty(GET_MEMBER_NAME_CHECKED(UPersonaPreviewSceneDescription, AdditionalMeshes));
		AdditionalMeshesProperty->SetOnPropertyResetToDefault(FSimpleDelegate::CreateSP(this, &FPreviewSceneDescriptionCustomization::OnResetAdditionalMeshes));
		
		// set the skeleton to use in our factory as we shouldn't be picking one here
		FactoryToUse->CurrentSkeleton = EditableSkeleton.IsValid() ? MakeWeakObjectPtr(const_cast<USkeleton*>(&EditableSkeleton.Pin()->GetSkeleton())) : nullptr;
		TArray<UFactory*> FactoriesToUse({ FactoryToUse });

		// bAllowPreviewMeshCollectionsToSelectFromDifferentSkeletons option
		DetailBuilder.EditCategory("Additional Meshes")
		.AddCustomRow(LOCTEXT("AdditionalMeshOption", "Additional Mesh Selection Option"))
		.NameContent()
		[
			SNew(STextBlock)
			.Font(IDetailLayoutBuilder::GetDetailFont())
			.Text(LOCTEXT("AdditionalMeshSelectionFromDifferentSkeletons", "Allow Different Skeletons"))
			.ToolTipText(LOCTEXT("AdditionalMeshSelectionFromDifferentSkeletons_ToolTip", "When selecting additional mesh, whether or not filter by the current skeleton."))
		]
		.ValueContent()
		[
			SNew(SCheckBox)
			.IsChecked(this, &FPreviewSceneDescriptionCustomization::HandleAllowDifferentSkeletonsIsChecked)
			.OnCheckStateChanged(this, &FPreviewSceneDescriptionCustomization::HandleAllowDifferentSkeletonsCheckedStateChanged)
		];
	
		// bAllowPreviewMeshCollectionsToSelectFromDifferentSkeletons option
		DetailBuilder.EditCategory("Additional Meshes")
		.AddCustomRow(LOCTEXT("AdditionalMeshOption_AnimBP", "Additional Mesh Anim Selection Option"))
		.NameContent()
		[
			SNew(STextBlock)
			.Font(IDetailLayoutBuilder::GetDetailFont())
			.Text(LOCTEXT("UseCustomAnimBP", "Allow Custom AnimBP Override"))
			.ToolTipText(LOCTEXT("UseCustomAnimBP_ToolTip", "When using preview collection, allow it to override custom AnimBP also."))
		]
		.ValueContent()
		[
			SNew(SCheckBox)
			.IsChecked(this, &FPreviewSceneDescriptionCustomization::HandleUseCustomAnimBPIsChecked)
			.OnCheckStateChanged(this, &FPreviewSceneDescriptionCustomization::HandleUseCustomAnimBPCheckedStateChanged)
		];

		FResetToDefaultOverride ResetToDefaultOverride = FResetToDefaultOverride::Create(
			FIsResetToDefaultVisible::CreateSP(this, &FPreviewSceneDescriptionCustomization::GetReplaceVisibility),
			FResetToDefaultHandler::CreateSP(this, &FPreviewSceneDescriptionCustomization::OnResetToBaseClicked)
		);

		DetailBuilder.EditCategory("Additional Meshes")
		.AddProperty(AdditionalMeshesProperty)
		.CustomWidget()
		.OverrideResetToDefault(ResetToDefaultOverride)
		.NameContent()
		[
			AdditionalMeshesProperty->CreatePropertyNameWidget()
		]
		.ValueContent()
		.MaxDesiredWidth(250.0f)
		.MinDesiredWidth(250.0f)
		[
			SNew(SHorizontalBox)
			+SHorizontalBox::Slot()
			.FillWidth(1.0f)
			[
				SNew(SObjectPropertyEntryBox)
				// searching uobject is too much for a scale of Fortnite
				// for now we just allow UDataAsset
				.AllowedClass(UDataAsset::StaticClass())
				.PropertyHandle(AdditionalMeshesProperty)
				.OnShouldFilterAsset(this, &FPreviewSceneDescriptionCustomization::HandleShouldFilterAdditionalMesh, true)
				.OnObjectChanged(this, &FPreviewSceneDescriptionCustomization::HandleAdditionalMeshesChanged, &DetailBuilder)
				.ThumbnailPool(DetailBuilder.GetThumbnailPool())
				.NewAssetFactories(FactoriesToUse)
			]
			+SHorizontalBox::Slot()
			.VAlign(VAlign_Center)
			.AutoWidth()
			.Padding(2.0f)
			[
				SNew(SButton)
				.Visibility(this, &FPreviewSceneDescriptionCustomization::GetSaveButtonVisibility, AdditionalMeshesProperty.ToSharedRef())
				.ButtonStyle(FAppStyle::Get(), "HoverHintOnly")
				.OnClicked(this, &FPreviewSceneDescriptionCustomization::OnSaveCollectionClicked, AdditionalMeshesProperty.ToSharedRef(), &DetailBuilder)
				.ContentPadding(4.0f)
				.ForegroundColor(FSlateColor::UseForeground())
				[
					SNew(SImage)
					.Image(FAppStyle::GetBrush("Persona.SavePreviewMeshCollection"))
					.ColorAndOpacity(FSlateColor::UseForeground())
				]
			]
		];

		FAssetData AdditionalMeshesAsset;
		AdditionalMeshesProperty->GetValue(AdditionalMeshesAsset);
		if (AdditionalMeshesAsset.IsValid())
		{
			TArray<UObject*> Objects;
			Objects.Add(AdditionalMeshesAsset.GetAsset());

			IDetailPropertyRow* PropertyRow = DetailBuilder.EditCategory("Additional Meshes")
			.AddExternalObjectProperty(Objects, "SkeletalMeshes");

			if (PropertyRow)
			{
				PropertyRow->ShouldAutoExpand(true);
			}
		}
	}
}

EVisibility FPreviewSceneDescriptionCustomization::GetSaveButtonVisibility(TSharedRef<IPropertyHandle> InAdditionalMeshesProperty) const
{
	FAssetData AdditionalMeshesAsset;
	InAdditionalMeshesProperty->GetValue(AdditionalMeshesAsset);
	UObject* Object = AdditionalMeshesAsset.GetAsset();

	return Object == nullptr || !Object->HasAnyFlags(RF_Transient) ? EVisibility::Collapsed : EVisibility::Visible;
}

FReply FPreviewSceneDescriptionCustomization::OnSaveCollectionClicked(TSharedRef<IPropertyHandle> InAdditionalMeshesProperty, IDetailLayoutBuilder* DetailLayoutBuilder)
{
	FAssetData AdditionalMeshesAsset;
	InAdditionalMeshesProperty->GetValue(AdditionalMeshesAsset);
	UPreviewMeshCollection* DefaultPreviewMeshCollection = CastChecked<UPreviewMeshCollection>(AdditionalMeshesAsset.GetAsset());
	if (DefaultPreviewMeshCollection)
	{
		IAssetTools& AssetTools = FModuleManager::GetModuleChecked<FAssetToolsModule>("AssetTools").Get();
		UPreviewMeshCollection* NewPreviewMeshCollection = Cast<UPreviewMeshCollection>(AssetTools.CreateAssetWithDialog(UPreviewMeshCollection::StaticClass(), FactoryToUse));
		if (NewPreviewMeshCollection)
		{
			NewPreviewMeshCollection->Skeleton = DefaultPreviewMeshCollection->Skeleton;
			NewPreviewMeshCollection->SkeletalMeshes = DefaultPreviewMeshCollection->SkeletalMeshes;
			InAdditionalMeshesProperty->SetValue(FAssetData(NewPreviewMeshCollection));
			PreviewScene.Pin()->SetAdditionalMeshes(NewPreviewMeshCollection);

			DetailLayoutBuilder->ForceRefreshDetails();
		}
	}

	return FReply::Handled();
}

bool FPreviewSceneDescriptionCustomization::HandleShouldFilterAdditionalMesh(const FAssetData& InAssetData, bool bCanUseDifferentSkeleton)
{
	// see if it's in valid class set
	bool bValidClass = false;

	// first to see if it's allowed class
	for (FTopLevelAssetPath ClassName: AvailableClassNameList)
	{
		if (ClassName == InAssetData.AssetClassPath)
		{
			bValidClass = true;
			break;
		}
	}

	// not valid class, filter it
	if (!bValidClass)
	{
		return true;
	}

	return HandleShouldFilterAsset(InAssetData, USkeletalMesh::GetSkeletonMemberName(), bCanUseDifferentSkeleton);
}

bool FPreviewSceneDescriptionCustomization::HandleShouldFilterAsset(const FAssetData& InAssetData, FName InTag, bool bCanUseDifferentSkeleton)
{
	if (bCanUseDifferentSkeleton && GetDefault<UPersonaOptions>()->bAllowPreviewMeshCollectionsToSelectFromDifferentSkeletons)
	{
		return false;
	}

	if(!PersonaToolkit.IsValid())
	{
		return false;
	}
	
	const USkeleton* Skeleton = PersonaToolkit.Pin()->GetSkeleton();
	const FString SkeletonTag = InAssetData.GetTagValueRef<FString>(InTag);
	if (Skeleton && Skeleton->IsCompatibleForEditor(SkeletonTag))
	{
		return false;
	}

	return true;
}

FText FPreviewSceneDescriptionCustomization::GetCurrentPreviewControllerText() const
{
	UPersonaPreviewSceneDescription* PersonaPreviewSceneDescription = PreviewScene.Pin()->GetPreviewSceneDescription();
	return PersonaPreviewSceneDescription->PreviewController->GetDisplayNameText();
}

TSharedRef<SWidget> FPreviewSceneDescriptionCustomization::MakeControllerComboEntryWidget(TSharedPtr<FPersonaModeComboEntry> InItem) const
{
	return
		SNew(STextBlock)
		.Text(InItem->Text);
}

void FPreviewSceneDescriptionCustomization::OnComboSelectionChanged(TSharedPtr<FPersonaModeComboEntry> InSelectedItem, ESelectInfo::Type SelectInfo)
{
	TSharedPtr<FAnimationEditorPreviewScene> PreviewScenePtr = PreviewScene.Pin();

	const FScopedTransaction Transaction(LOCTEXT("ChangePreviewSceneController", "Setting Preview Scene Controller"));
	UPersonaPreviewSceneDescription* PersonaPreviewSceneDescription = PreviewScenePtr->GetPreviewSceneDescription();
	PersonaPreviewSceneDescription->Modify();

	PersonaPreviewSceneDescription->SetPreviewController(InSelectedItem->Class, PreviewScenePtr.Get());

	MyDetailLayout->ForceRefreshDetails();
}

void FPreviewSceneDescriptionCustomization::HandlePreviewControllerPropertyChanged()
{
	ReinitializePreviewController();
}

void FPreviewSceneDescriptionCustomization::HandleMeshChanged(const FAssetData& InAssetData)   
{
	USkeletalMesh* NewPreviewMesh = Cast<USkeletalMesh>(InAssetData.GetAsset());
	PersonaToolkit.Pin()->SetPreviewMesh(NewPreviewMesh, false);
}

void FPreviewSceneDescriptionCustomization::HandlePreviewAnimBlueprintChanged(const FAssetData& InAssetData)
{
	UAnimBlueprint* NewAnimBlueprint = Cast<UAnimBlueprint>(InAssetData.GetAsset());
	PersonaToolkit.Pin()->SetPreviewAnimationBlueprint(NewAnimBlueprint);
}

void FPreviewSceneDescriptionCustomization::HandleAnimBlueprintCompiled(UBlueprint* Blueprint)
{
	// Only re-initialize controller if we are not debugging an external instance.
	// If we switch at this point then we will disconnect from the external instance
	const TSharedPtr<FAnimationEditorPreviewScene> AnimPreviewScene = PreviewScene.Pin();
	if(AnimPreviewScene->GetPreviewMeshComponent()->PreviewInstance == nullptr || AnimPreviewScene->GetPreviewMeshComponent()->PreviewInstance->GetDebugSkeletalMeshComponent() == nullptr)
	{
		UPersonaPreviewSceneDescription* PersonaPreviewSceneDescription = AnimPreviewScene->GetPreviewSceneDescription();
		PersonaPreviewSceneDescription->PreviewControllerInstance->UninitializeView(PersonaPreviewSceneDescription, AnimPreviewScene.Get());
		PersonaPreviewSceneDescription->PreviewControllerInstance->InitializeView(PersonaPreviewSceneDescription, AnimPreviewScene.Get());
	}
}

void FPreviewSceneDescriptionCustomization::HandleAdditionalMeshesChanged(const FAssetData& InAssetData, IDetailLayoutBuilder* DetailLayoutBuilder)
{
	UDataAsset* MeshCollection = Cast<UDataAsset>(InAssetData.GetAsset());
	if (!MeshCollection || MeshCollection->GetClass()->ImplementsInterface(UPreviewCollectionInterface::StaticClass()))
	{
		PreviewScene.Pin()->SetAdditionalMeshes(MeshCollection);
	}

	DataAssetToDisplay = MeshCollection;
	DetailLayoutBuilder->ForceRefreshDetails();
}

void FPreviewSceneDescriptionCustomization::HandleAllowDifferentSkeletonsCheckedStateChanged(ECheckBoxState CheckState)
{
	const FScopedTransaction Transaction(LOCTEXT("AllowDifferentSkeletons", "Setting Allow Different Skeletons"));
	UPersonaOptions* PersonaOptions = GetMutableDefault<UPersonaOptions>();
	PersonaOptions->Modify();
	
	PersonaOptions->bAllowPreviewMeshCollectionsToSelectFromDifferentSkeletons = (CheckState == ECheckBoxState::Checked);
}

ECheckBoxState FPreviewSceneDescriptionCustomization::HandleAllowDifferentSkeletonsIsChecked() const
{
	return GetDefault<UPersonaOptions>()->bAllowPreviewMeshCollectionsToSelectFromDifferentSkeletons? ECheckBoxState::Checked : ECheckBoxState::Unchecked;
}

void FPreviewSceneDescriptionCustomization::HandleUseCustomAnimBPCheckedStateChanged(ECheckBoxState CheckState)
{
	const FScopedTransaction Transaction(LOCTEXT("AllowDifferentSkeletons", "Setting Allow Different Skeletons"));
	UPersonaOptions* PersonaOptions = GetMutableDefault<UPersonaOptions>();
	PersonaOptions->Modify();	
	PersonaOptions->bAllowPreviewMeshCollectionsToUseCustomAnimBP = (CheckState == ECheckBoxState::Checked);

	if (PreviewScene.IsValid())
	{
		PreviewScene.Pin()->RefreshAdditionalMeshes(false);
	}
}

ECheckBoxState FPreviewSceneDescriptionCustomization::HandleUseCustomAnimBPIsChecked() const
{
	return GetDefault<UPersonaOptions>()->bAllowPreviewMeshCollectionsToUseCustomAnimBP? ECheckBoxState::Checked : ECheckBoxState::Unchecked;
}

void FPreviewSceneDescriptionCustomization::ReinitializePreviewController()
{
	TSharedPtr<FAnimationEditorPreviewScene> PreviewScenePtr = PreviewScene.Pin();
	UPersonaPreviewSceneDescription* PersonaPreviewSceneDescription = PreviewScenePtr->GetPreviewSceneDescription();
	
	PersonaPreviewSceneDescription->PreviewControllerInstance->UninitializeView(PersonaPreviewSceneDescription, PreviewScenePtr.Get());
	PersonaPreviewSceneDescription->PreviewControllerInstance->InitializeView(PersonaPreviewSceneDescription, PreviewScenePtr.Get());
}

bool FPreviewSceneDescriptionCustomization::GetReplaceVisibility(TSharedPtr<IPropertyHandle> PropertyHandle) const
{
	// Only show the replace button if the current material can be replaced
 	if (AdditionalMeshesProperty.IsValid())
 	{
 		FAssetData AdditionalMeshesAsset;
 		AdditionalMeshesProperty->GetValue(AdditionalMeshesAsset);
 		return AdditionalMeshesAsset.IsValid();
 	}

	return false;
}

/**
* Called when reset to base is clicked
*/
void FPreviewSceneDescriptionCustomization::OnResetToBaseClicked(TSharedPtr<IPropertyHandle> PropertyHandle)
{
	// Only allow reset to base if the current material can be replaced
 	if (AdditionalMeshesProperty.IsValid())
 	{
		FAssetData NullAsset;
		AdditionalMeshesProperty->SetValue(NullAsset);

		PreviewScene.Pin()->SetAdditionalMeshes(nullptr);
 	}
}

void FPreviewSceneDescriptionCustomization::OnResetAdditionalMeshes()
{	
	// this function resets the additional meshes property to null,
	// in the future if we serialize the default setting, this will
	// need to reset it to the default value, not just null.

	// Only allow reset to base if the current material can be replaced
	if (AdditionalMeshesProperty.IsValid())
	{
		FAssetData NullAsset;
		AdditionalMeshesProperty->SetValue(NullAsset);

		PreviewScene.Pin()->SetAdditionalMeshes(nullptr);
	}

	MyDetailLayout->ForceRefreshDetails();
}

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// 
// FPreviewMeshCollectionEntryCustomization
// 
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

void FPreviewMeshCollectionEntryCustomization::CustomizeHeader(TSharedRef<IPropertyHandle> PropertyHandle, FDetailWidgetRow& HeaderRow, IPropertyTypeCustomizationUtils& CustomizationUtils)
{
	// get the enclosing preview mesh collection to determine the skeleton we want
	TArray<UObject*> OuterObjects;
	PropertyHandle->GetOuterObjects(OuterObjects);

	check(OuterObjects.Num() > 0);
		
	if (OuterObjects[0] != nullptr)
	{
		FString SkeletonName = FAssetData(CastChecked<UPreviewMeshCollection>(OuterObjects[0])->Skeleton).GetExportTextName();
		USkeleton* Skeleton = CastChecked<UPreviewMeshCollection>(OuterObjects[0])->Skeleton;
		PropertyHandle->GetParentHandle()->SetOnPropertyValueChanged(FSimpleDelegate::CreateSP(this, &FPreviewMeshCollectionEntryCustomization::HandleMeshesArrayChanged, CustomizationUtils.GetPropertyUtilities()));

		TSharedPtr<IPropertyHandle> SkeletalMeshProperty = PropertyHandle->GetChildHandle(GET_MEMBER_NAME_CHECKED(FPreviewMeshCollectionEntry, SkeletalMesh));
		TSharedPtr<IPropertyHandle> AnimBlueprintProperty = PropertyHandle->GetChildHandle(GET_MEMBER_NAME_CHECKED(FPreviewMeshCollectionEntry, AnimBlueprint));
		if (SkeletalMeshProperty.IsValid() && AnimBlueprintProperty.IsValid())
		{
			HeaderRow.NameContent()
			[
				SkeletalMeshProperty->CreatePropertyNameWidget()
			]
			.ValueContent()
			.MaxDesiredWidth(250.0f)
			.MinDesiredWidth(250.0f)
			[
				SNew(SVerticalBox)
				+SVerticalBox::Slot()
				[
					SNew(SObjectPropertyEntryBox)
					.AllowedClass(USkeletalMesh::StaticClass())
					.PropertyHandle(SkeletalMeshProperty)
					.OnShouldFilterAsset(this, &FPreviewMeshCollectionEntryCustomization::HandleShouldFilterAsset, SkeletonName, Skeleton)
					.OnObjectChanged(this, &FPreviewMeshCollectionEntryCustomization::HandleMeshChanged)
					.ThumbnailPool(CustomizationUtils.GetThumbnailPool())
				]
				+SVerticalBox::Slot()
				[
					SNew(SObjectPropertyEntryBox)
					.AllowedClass(UAnimBlueprint::StaticClass())
					.PropertyHandle(AnimBlueprintProperty)
					.OnObjectChanged(this, &FPreviewMeshCollectionEntryCustomization::HandleMeshChanged)
					.ThumbnailPool(CustomizationUtils.GetThumbnailPool())
				]
			];
		}
	}
}

bool FPreviewMeshCollectionEntryCustomization::HandleShouldFilterAsset(const FAssetData& InAssetData, FString SkeletonName, USkeleton* Skeleton)
{
	if (GetDefault<UPersonaOptions>()->bAllowPreviewMeshCollectionsToSelectFromDifferentSkeletons)
	{
		return false;
	}

	if (Skeleton && Skeleton->IsCompatibleForEditor(InAssetData))
	{
		return false;
	}

	return true;
}

void FPreviewMeshCollectionEntryCustomization::HandleMeshChanged(const FAssetData& InAssetData)
{
	if (PreviewScene.IsValid())
	{
		// if mesh changes, don't override base mesh
		PreviewScene.Pin()->RefreshAdditionalMeshes(false);
	}
}

void FPreviewMeshCollectionEntryCustomization::HandleMeshesArrayChanged(TSharedPtr<IPropertyUtilities> PropertyUtilities)
{
	if (PreviewScene.IsValid())
	{
		// if additional mesh changes, allow it to override
		PreviewScene.Pin()->RefreshAdditionalMeshes(true);
		if (PropertyUtilities.IsValid())
		{
			PropertyUtilities->ForceRefresh();
		}
	}
}

#if CHAOS_SIMULATION_DETAIL_VIEW_FACTORY_SELECTOR
TSharedRef<SWidget> FPreviewSceneDescriptionCustomization::MakeClothingSimulationFactoryWidget(TSharedPtr<TSubclassOf<class UClothingSimulationFactory>> Item) const
{
	return SNew(STextBlock)
		.Text(*Item ? FText::FromName((*Item)->GetFName()) : LOCTEXT("PhysicsClothingSimulationFactory_NoneSelected", "None"))
		.Font(IDetailLayoutBuilder::GetDetailFont());
}

void FPreviewSceneDescriptionCustomization::OnClothingSimulationFactorySelectionChanged(TSharedPtr<TSubclassOf<class UClothingSimulationFactory>> Item, ESelectInfo::Type SelectInfo) const
{
	// Set new factory to the preview mesh component:
	if (const TSharedPtr<IPersonaToolkit> PersonaToolkitPin = PersonaToolkit.Pin())
	{
		if (UDebugSkelMeshComponent* const DebugSkelMeshComponent = PersonaToolkitPin->GetPreviewMeshComponent())
		{
			DebugSkelMeshComponent->UnregisterComponent();
			DebugSkelMeshComponent->ClothingSimulationFactory = *Item;
			DebugSkelMeshComponent->RegisterComponent();
		}
	}
}

FText FPreviewSceneDescriptionCustomization::GetCurrentClothingSimulationFactoryText() const
{
	TSubclassOf<class UClothingSimulationFactory> Item;
	if (const TSharedPtr<IPersonaToolkit> PersonaToolkitPin = PersonaToolkit.Pin())
	{
		if (const UDebugSkelMeshComponent* const DebugSkelMeshComponent = PersonaToolkitPin->GetPreviewMeshComponent())
		{
			Item = DebugSkelMeshComponent->ClothingSimulationFactory;
		}
	}
	return *Item ? FText::FromName((*Item)->GetFName()) : LOCTEXT("PhysicsClothingSimulationFactory_NoneSelected", "None");
}
#endif  // #if CHAOS_SIMULATION_DETAIL_VIEW_FACTORY_SELECTOR
#undef LOCTEXT_NAMESPACE