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

#include "EditNormalsTool.h"
#include "InteractiveToolManager.h"
#include "ToolBuilderUtil.h"

#include "ToolSetupUtil.h"
#include "ModelingToolTargetUtil.h"

#include "DynamicMesh/DynamicMesh3.h"
#include "BaseBehaviors/MultiClickSequenceInputBehavior.h"
#include "Selection/SelectClickedAction.h"

#include "MeshDescriptionToDynamicMesh.h"
#include "DynamicMeshToMeshDescription.h"

#include "InteractiveGizmoManager.h"

#include "AssetUtils/MeshDescriptionUtil.h"
#include "Engine/StaticMesh.h"
#include "Components/StaticMeshComponent.h"

#include "TargetInterfaces/PrimitiveComponentBackedTarget.h"
#include "ModelingToolTargetUtil.h"

using namespace UE::Geometry;

#define LOCTEXT_NAMESPACE "UEditNormalsTool"

/*
 * ToolBuilder
 */


UMultiSelectionMeshEditingTool* UEditNormalsToolBuilder::CreateNewTool(const FToolBuilderState& SceneState) const
{
	return NewObject<UEditNormalsTool>(SceneState.ToolManager);
}




/*
 * Tool
 */

UEditNormalsToolProperties::UEditNormalsToolProperties()
{
	bFixInconsistentNormals = false;
	bInvertNormals = false;
	bRecomputeNormals = true;
	NormalCalculationMethod = ENormalCalculationMethod::AreaAngleWeighting;
	SplitNormalMethod = ESplitNormalMethod::UseExistingTopology;
	SharpEdgeAngleThreshold = 60;
	bAllowSharpVertices = false;
}

UEditNormalsAdvancedProperties::UEditNormalsAdvancedProperties()
{
}


UEditNormalsTool::UEditNormalsTool()
{
}


void UEditNormalsTool::Setup()
{
	UInteractiveTool::Setup();

	// hide input StaticMeshComponent
	for (int32 ComponentIdx = 0, NumTargets = Targets.Num(); ComponentIdx < NumTargets; ComponentIdx++)
	{
		UE::ToolTarget::HideSourceObject(Targets[ComponentIdx]);
	}

	BasicProperties = NewObject<UEditNormalsToolProperties>(this, TEXT("Mesh Normals Settings"));
	BasicProperties->RestoreProperties(this);
	AddToolPropertySource(BasicProperties);

	AdvancedProperties = NewObject<UEditNormalsAdvancedProperties>(this, TEXT("Advanced Settings"));
	AdvancedProperties->RestoreProperties(this);
	AddToolPropertySource(AdvancedProperties);

	// initialize the PreviewMesh+BackgroundCompute object
	UpdateNumPreviews();

	
	
	for (UMeshOpPreviewWithBackgroundCompute* Preview : Previews)
	{
		Preview->InvalidateResult();
	}

	SetToolDisplayName(LOCTEXT("ToolName", "Edit Normals"));
	GetToolManager()->DisplayMessage(
		LOCTEXT("OnStartTool", "Configure or Recalculate Normals on a Mesh (disables autogenerated Normals)"),
		EToolMessageLevel::UserNotification);
}


void UEditNormalsTool::UpdateNumPreviews()
{
	int32 CurrentNumPreview = Previews.Num();
	int32 TargetNumPreview = Targets.Num();
	if (TargetNumPreview < CurrentNumPreview)
	{
		for (int32 PreviewIdx = CurrentNumPreview - 1; PreviewIdx >= TargetNumPreview; PreviewIdx--)
		{
			Previews[PreviewIdx]->Cancel();
		}
		Previews.SetNum(TargetNumPreview);
		OriginalDynamicMeshes.SetNum(TargetNumPreview);
	}
	else
	{
		OriginalDynamicMeshes.SetNum(TargetNumPreview);
		for (int32 PreviewIdx = CurrentNumPreview; PreviewIdx < TargetNumPreview; PreviewIdx++)
		{
			UEditNormalsOperatorFactory *OpFactory = NewObject<UEditNormalsOperatorFactory>();
			OpFactory->Tool = this;
			OpFactory->ComponentIndex = PreviewIdx;
			OriginalDynamicMeshes[PreviewIdx] = MakeShared<FDynamicMesh3, ESPMode::ThreadSafe>();
			FMeshDescriptionToDynamicMesh Converter;
			Converter.Convert(UE::ToolTarget::GetMeshDescription(Targets[PreviewIdx]), *OriginalDynamicMeshes[PreviewIdx]);

			UMeshOpPreviewWithBackgroundCompute* Preview = Previews.Add_GetRef(NewObject<UMeshOpPreviewWithBackgroundCompute>(OpFactory, "Preview"));
			Preview->Setup(GetTargetWorld(), OpFactory);
			ToolSetupUtil::ApplyRenderingConfigurationToPreview(Preview->PreviewMesh, Targets[PreviewIdx]);
			Preview->PreviewMesh->SetTangentsMode(EDynamicMeshComponentTangentsMode::AutoCalculated);

			const FComponentMaterialSet MaterialSet = UE::ToolTarget::GetMaterialSet(Targets[PreviewIdx]);
			Preview->ConfigureMaterials(MaterialSet.Materials,
				ToolSetupUtil::GetDefaultWorkingMaterial(GetToolManager())
			);

			Preview->SetVisibility(true);
		}
	}
}


void UEditNormalsTool::OnShutdown(EToolShutdownType ShutdownType)
{
	BasicProperties->SaveProperties(this);
	AdvancedProperties->SaveProperties(this);

	// Restore (unhide) the source meshes
	for (int32 ComponentIdx = 0, NumTargets = Targets.Num(); ComponentIdx < NumTargets; ComponentIdx++)
	{
		UE::ToolTarget::ShowSourceObject(Targets[ComponentIdx]);
	}

	TArray<FDynamicMeshOpResult> Results;
	for (UMeshOpPreviewWithBackgroundCompute* Preview : Previews)
	{
		Results.Add(Preview->Shutdown());
	}
	if (ShutdownType == EToolShutdownType::Accept)
	{
		GenerateAsset(Results);
	}
}

TUniquePtr<FDynamicMeshOperator> UEditNormalsOperatorFactory::MakeNewOperator()
{
	TUniquePtr<FEditNormalsOp> NormalsOp = MakeUnique<FEditNormalsOp>();
	NormalsOp->bFixInconsistentNormals = Tool->BasicProperties->bFixInconsistentNormals;
	NormalsOp->bInvertNormals = Tool->BasicProperties->bInvertNormals;
	NormalsOp->bRecomputeNormals = Tool->BasicProperties->bRecomputeNormals;
	NormalsOp->SplitNormalMethod = Tool->BasicProperties->SplitNormalMethod;
	NormalsOp->bAllowSharpVertices = Tool->BasicProperties->bAllowSharpVertices;
	NormalsOp->NormalCalculationMethod = Tool->BasicProperties->NormalCalculationMethod;
	NormalsOp->NormalSplitThreshold = Tool->BasicProperties->SharpEdgeAngleThreshold;

	const FTransform LocalToWorld = (FTransform) UE::ToolTarget::GetLocalToWorldTransform(Tool->Targets[ComponentIndex]);
	NormalsOp->OriginalMesh = Tool->OriginalDynamicMeshes[ComponentIndex];
	
	NormalsOp->SetTransform(LocalToWorld);

	return NormalsOp;
}



void UEditNormalsTool::Render(IToolsContextRenderAPI* RenderAPI)
{
}

void UEditNormalsTool::OnTick(float DeltaTime)
{
	for (UMeshOpPreviewWithBackgroundCompute* Preview : Previews)
	{
		Preview->Tick(DeltaTime);
	}
}



#if WITH_EDITOR
void UEditNormalsTool::PostEditChangeProperty(FPropertyChangedEvent& PropertyChangedEvent)
{
	UpdateNumPreviews();
	for (UMeshOpPreviewWithBackgroundCompute* Preview : Previews)
	{
		Preview->InvalidateResult();
	}
}
#endif

void UEditNormalsTool::OnPropertyModified(UObject* PropertySet, FProperty* Property)
{
	UpdateNumPreviews();
	for (UMeshOpPreviewWithBackgroundCompute* Preview : Previews)
	{
		Preview->InvalidateResult();
	}
}



bool UEditNormalsTool::HasAccept() const
{
	return true;
}

bool UEditNormalsTool::CanAccept() const
{
	for (UMeshOpPreviewWithBackgroundCompute* Preview : Previews)
	{
		if (!Preview->HaveValidResult())
		{
			return false;
		}
	}
	return Super::CanAccept();
}


void UEditNormalsTool::GenerateAsset(const TArray<FDynamicMeshOpResult>& Results)
{
	GetToolManager()->BeginUndoTransaction(LOCTEXT("EditNormalsToolTransactionName", "Edit Normals Tool"));

	check(Results.Num() == Targets.Num());
	
	for (int32 ComponentIdx = 0; ComponentIdx < Targets.Num(); ComponentIdx++)
	{
		// disable auto-generated normals StaticMesh build setting
		UStaticMeshComponent* StaticMeshComponent = Cast<UStaticMeshComponent>(UE::ToolTarget::GetTargetComponent(Targets[ComponentIdx]));
		if (StaticMeshComponent != nullptr)
		{
			UStaticMesh* StaticMesh = StaticMeshComponent->GetStaticMesh();
			if (ensure(StaticMesh != nullptr))
			{
				StaticMesh->Modify();
				UE::MeshDescription::FStaticMeshBuildSettingChange SettingsChange;
				SettingsChange.AutoGeneratedNormals = UE::MeshDescription::EBuildSettingBoolChange::Disable;
				UE::MeshDescription::ConfigureBuildSettings(StaticMesh, 0, SettingsChange);
			}
		}

		const FDynamicMesh3* NewDynamicMesh = Results[ComponentIdx].Mesh.Get();
		if (NewDynamicMesh)
		{
			if (bool bTopologyChanged = BasicProperties->WillTopologyChange())
			{
				// Tool may have changed the topology of the normal overlay (according to the specified tool properties), so we can't simply update the target mesh.
				// Passing in bTopologyChanged = true will trigger the slower Convert function rather than the fast Update function.
				UE::ToolTarget::CommitMeshDescriptionUpdateViaDynamicMesh(Targets[ComponentIdx], *NewDynamicMesh, bTopologyChanged);
			}
			else
			{
				// The tool didn't change the overlay topology so there's a chance we can do a fast path Update of the normal attributes.
				// This function will still check if there is a mismatch between the dynamic mesh and target mesh in terms of triangles/vertices, and
				// if so it will do the full conversion.
				constexpr bool bUpdateTangents = false;
				UE::ToolTarget::CommitDynamicMeshNormalsUpdate(Targets[ComponentIdx], NewDynamicMesh, bUpdateTangents);
			}
		}
	}

	GetToolManager()->EndUndoTransaction();
}




#undef LOCTEXT_NAMESPACE