// Copyright UShaderLab. All Rights Reserved.
//
// View / camera / screen intrinsics.

#include "ShaderLabIntrinsics.h"

#include "Materials/MaterialExpressionCameraPositionWS.h"
#include "Materials/MaterialExpressionCameraVectorWS.h"
#include "Materials/MaterialExpressionEyeAdaptation.h"
#include "Materials/MaterialExpressionIsFirstPerson.h"
#include "Materials/MaterialExpressionIsOrthographic.h"
#include "Materials/MaterialExpressionLightVector.h"
#include "Materials/MaterialExpressionMainDirectionalLight.h"
#include "Materials/MaterialExpressionPixelDepth.h"
#include "Materials/MaterialExpressionReflectionVectorWS.h"
#include "Materials/MaterialExpressionSceneTexelSize.h"
#include "Materials/MaterialExpressionScreenPosition.h"
#include "Materials/MaterialExpressionViewProperty.h"
#include "Materials/MaterialExpressionViewSize.h"
#include "Materials/MaterialExpressionWorldPosition.h"

void RegisterViewIntrinsics(FShaderLabIntrinsicRegistry& Registry)
{
	using namespace ShaderLabIntrinsic_Private;
	using EFreq = EShaderLabIntrinsicFrequency;

	AddSimple(Registry, TEXT("WorldPosition"), EFreq::Any, TEXT("float3"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionWorldPosition>(M); });
	AddSimple(Registry, TEXT("CameraPositionWS"), EFreq::Any, TEXT("float3"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionCameraPositionWS>(M); });
	AddSimple(Registry, TEXT("CameraVectorWS"), EFreq::Any, TEXT("float3"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionCameraVectorWS>(M); });
	AddSimple(Registry, TEXT("LightVector"), EFreq::Any, TEXT("float3"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionLightVector>(M); });
	AddSimple(Registry, TEXT("PixelDepth"), EFreq::PixelOnly, TEXT("float"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionPixelDepth>(M); });
	AddSimple(Registry, TEXT("ScreenPosition"), EFreq::PixelOnly, TEXT("float2"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionScreenPosition>(M); });
	AddSimple(Registry, TEXT("ReflectionVectorWS"), EFreq::PixelOnly, TEXT("float3"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionReflectionVectorWS>(M); });
	AddSimple(Registry, TEXT("ViewSize"), EFreq::Any, TEXT("float2"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionViewSize>(M); });
	AddSimple(Registry, TEXT("SceneTexelSize"), EFreq::Any, TEXT("float2"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionSceneTexelSize>(M); });
	AddSimple(Registry, TEXT("IsOrthographic"), EFreq::Any, TEXT("float"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionIsOrthographic>(M); });
	AddSimple(Registry, TEXT("EyeAdaptation"), EFreq::PixelOnly, TEXT("float"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionEyeAdaptation>(M); });
	AddSimple(Registry, TEXT("IsFirstPerson"), EFreq::Any, TEXT("float"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionIsFirstPerson>(M); });

	// MainDirectionalLight is multi-output (Illuminance, Direction) — one intrinsic per output pin.
	AddSimple(Registry, TEXT("MainDirectionalLightIlluminance"), EFreq::PixelOnly, TEXT("float3"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionMainDirectionalLight>(M); }, 0);
	AddSimple(Registry, TEXT("MainDirectionalLightDirection"), EFreq::PixelOnly, TEXT("float3"), [](UMaterial& M) { return MakeSimple<UMaterialExpressionMainDirectionalLight>(M); }, 1);

	// ViewProperty(Property) — Property is an EMaterialExposedViewProperty token.
	{
		FShaderLabIntrinsicDesc Desc;
		Desc.Name = FName(TEXT("ViewProperty"));
		Desc.ReturnType = TEXT("float4");
		Desc.Doc = TEXT("Property is an EMaterialExposedViewProperty token (e.g. MEVP_FieldOfView).");

		FShaderLabIntrinsicParam PropertyParam;
		PropertyParam.Name = TEXT("Property");
		// Safe: UShaderLabEditor depends on Engine, whose reflected enums register before any editor
		// code runs, and this executes lazily at first registry use (build/command/test time).
		PropertyParam.Enum = StaticEnum<EMaterialExposedViewProperty>();
		check(PropertyParam.Enum);
		Desc.Params = { MoveTemp(PropertyParam) };

		Desc.MakeNode = [](UMaterial& M, const TArray<FString>& Args, FString& OutError) -> UMaterialExpression*
		{
			UMaterialExpressionViewProperty* E = NewObject<UMaterialExpressionViewProperty>(&M);
			if (Args.Num() >= 1)
			{
				UEnum* Enum = StaticEnum<EMaterialExposedViewProperty>();
				check(Enum);
				const int64 Value = Enum->GetValueByNameString(Args[0]);
				if (Value == INDEX_NONE)
				{
					OutError = FString::Printf(TEXT("unknown view property '%s'"), *Args[0]);
					return nullptr;
				}
				E->Property = static_cast<EMaterialExposedViewProperty>(Value);
			}
			M.GetExpressionCollection().AddExpression(E);
			return E;
		};
		Registry.Register(MoveTemp(Desc));
	}
}