// Copyright Epic Games, Inc. All Rights Reserved.
 
#include "BaseGizmos/GizmoElementArrow.h"
#include "BaseGizmos/GizmoElementBox.h"
#include "BaseGizmos/GizmoElementCone.h"
#include "BaseGizmos/GizmoElementCylinder.h"
#include "BaseGizmos/GizmoMath.h"
#include "BaseGizmos/GizmoRenderingUtil.h"
#include "InputState.h"
#include "Materials/MaterialInterface.h"

UGizmoElementArrow::UGizmoElementArrow()
{
	HeadType = EGizmoElementArrowHeadType::Cone;
	CylinderElement = NewObject<UGizmoElementCylinder>();
	ConeElement = NewObject<UGizmoElementCone>();
	BoxElement = nullptr;
}

void UGizmoElementArrow::Render(IToolsContextRenderAPI* RenderAPI, const FRenderTraversalState& RenderState)
{
	if (!IsVisible())
	{
		return;
	}

	const FSceneView* View = RenderAPI->GetSceneView();
	bool bVisibleViewDependent = GetViewDependentVisibility(View, RenderState.LocalToWorldTransform, Base);

	FRenderTraversalState RenderStateCopy = RenderState;

	if (bVisibleViewDependent)
	{
		FQuat AlignRot;
		if (GetViewAlignRot(View, RenderState.LocalToWorldTransform, Base, AlignRot))
		{
			RenderStateCopy.LocalToWorldTransform = FTransform(AlignRot, Base) * RenderState.LocalToWorldTransform;
		}
		else
		{
			RenderStateCopy.LocalToWorldTransform = FTransform(Base) * RenderState.LocalToWorldTransform;
		}

		UpdateRenderTraversalState(RenderStateCopy);

		check(CylinderElement);
		UGizmoElementBase* Element = Cast<UGizmoElementBase>(CylinderElement);
		Element->Render(RenderAPI, RenderStateCopy);

		if (HeadType == EGizmoElementArrowHeadType::Cone)
		{
			check(ConeElement);
			ConeElement->Render(RenderAPI, RenderStateCopy);
		}
		else // (HeadType == EGizmoElementArrowHeadType::Cube)
		{
			check(BoxElement);
			BoxElement->Render(RenderAPI, RenderStateCopy);
		}
	}

	CacheRenderState(RenderStateCopy.LocalToWorldTransform, bVisibleViewDependent);
}

FInputRayHit UGizmoElementArrow::LineTrace(const FVector RayOrigin, const FVector RayDirection)
{
	if (!IsHittableInView())
	{
		return FInputRayHit();
	}

	check(CylinderElement);
	FInputRayHit Hit = CylinderElement->LineTrace(RayOrigin, RayDirection);

	if (!Hit.bHit)
	{
		if (HeadType == EGizmoElementArrowHeadType::Cone)
		{
			check(ConeElement);
			Hit = ConeElement->LineTrace(RayOrigin, RayDirection);
		}
		else // (HeadType == EGizmoElementArrowHeadType::Cube)
		{
			check(BoxElement);
			Hit = BoxElement->LineTrace(RayOrigin, RayDirection);
		}
	}

	if (Hit.bHit)
	{
		Hit.SetHitObject(this);
		Hit.HitIdentifier = PartIdentifier;
	}

	return Hit;
}

FBoxSphereBounds UGizmoElementArrow::CalcBounds(const FTransform& LocalToWorld) const
{
	// @todo - implement box-sphere bounds calculation
	return FBoxSphereBounds();
}

void UGizmoElementArrow::SetBase(const FVector& InBase)
{
	Base = InBase;
	UpdateArrowBody();
	UpdateArrowHead();
}

FVector UGizmoElementArrow::GetBase() const
{
	return Base;
}

void UGizmoElementArrow::SetDirection(const FVector& InDirection)
{
	Direction = InDirection;
	Direction.Normalize();
	UpdateArrowBody();
	UpdateArrowHead();
}

FVector UGizmoElementArrow::GetDirection() const
{
	return Direction;
}

void UGizmoElementArrow::SetSideDirection(const FVector& InSideDirection)
{
	SideDirection = InSideDirection;
	SideDirection.Normalize();
	UpdateArrowHead();
}

FVector UGizmoElementArrow::GetSideDirection() const
{
	return SideDirection;
}

void UGizmoElementArrow::SetBodyLength(float InBodyLength)
{
	BodyLength = InBodyLength;
	UpdateArrowBody();
	UpdateArrowHead();
}

float UGizmoElementArrow::GetBodyLength() const
{
	return BodyLength;
}

void UGizmoElementArrow::SetBodyRadius(float InBodyRadius)
{
	BodyRadius = InBodyRadius;
	UpdateArrowBody();
	UpdateArrowHead();
}

float UGizmoElementArrow::GetBodyRadius() const
{
	return BodyRadius;
}

void UGizmoElementArrow::SetHeadLength(float InHeadLength)
{
	HeadLength = InHeadLength;
	UpdateArrowHead();
}

float UGizmoElementArrow::GetHeadLength() const
{
	return HeadLength;
}

void UGizmoElementArrow::SetHeadRadius(float InHeadRadius)
{
	HeadRadius = InHeadRadius;
	UpdateArrowHead();
}

float UGizmoElementArrow::GetHeadRadius() const
{
	return HeadRadius;
}

void UGizmoElementArrow::SetNumSides(int32 InNumSides)
{
	NumSides = InNumSides;
	UpdateArrowBody();
	UpdateArrowHead();
}

int32 UGizmoElementArrow::GetNumSides() const
{
	return NumSides;
}

void UGizmoElementArrow::SetHeadType(EGizmoElementArrowHeadType InHeadType)
{
	if (InHeadType != HeadType)
	{
		HeadType = InHeadType;

		if (HeadType == EGizmoElementArrowHeadType::Cone)
		{
			ConeElement = NewObject<UGizmoElementCone>();
			BoxElement = nullptr;
		}
		else // (HeadType == EGizmoElementArrowHeadType::Cube)
		{
			BoxElement = NewObject<UGizmoElementBox>();
			ConeElement = nullptr;
		}
		UpdateArrowHead();
	}
}

EGizmoElementArrowHeadType UGizmoElementArrow::GetHeadType() const
{
	return HeadType;
}

void UGizmoElementArrow::UpdateArrowBody()
{
	CylinderElement->SetBase(FVector::ZeroVector);
	CylinderElement->SetDirection(Direction);
	CylinderElement->SetHeight(BodyLength);
	CylinderElement->SetNumSides(NumSides);
	CylinderElement->SetRadius(BodyRadius);
}

void UGizmoElementArrow::UpdateArrowHead()
{
	if (HeadType == EGizmoElementArrowHeadType::Cone)
	{
		check(ConeElement);
		// head length is multiplied by 0.9f to prevent gap between body cylinder and head cone
		ConeElement->SetOrigin(Direction * (BodyLength + HeadLength * 0.9f)); 
		ConeElement->SetDirection(-Direction);
		ConeElement->SetHeight(HeadLength);
		ConeElement->SetRadius(HeadRadius);
		ConeElement->SetNumSides(NumSides);
		ConeElement->SetElementInteractionState(ElementInteractionState);
	}
	else // (HeadType == EGizmoElementArrowHeadType::Cube)
	{
		check(BoxElement);
		BoxElement->SetCenter(Direction * (BodyLength + HeadLength * 0.5f));
		BoxElement->SetUpDirection(Direction);
		BoxElement->SetSideDirection(SideDirection);
		BoxElement->SetDimensions(FVector(HeadLength, HeadLength, HeadLength));
		BoxElement->SetElementInteractionState(ElementInteractionState);
	}
}