// Copyright 1998-2015 Epic Games, Inc. All Rights Reserved.
#pragma once

#include "DynamicMeshBuilder.h"
#include "Stats.h"

DECLARE_STATS_GROUP(TEXT("GeometryCache"), STATGROUP_GeometryCache, STATCAT_Advanced);
DECLARE_CYCLE_STAT(TEXT("MeshTime"), STAT_GeometryCacheSceneProxy_GetMeshElements, STATGROUP_GeometryCache );
DECLARE_DWORD_COUNTER_STAT(TEXT("Triangle Count"), STAT_GeometryCacheSceneProxy_TriangleCount, STATGROUP_GeometryCache);
DECLARE_DWORD_COUNTER_STAT(TEXT("Section Count"), STAT_GeometryCacheSceneProxy_MeshBatchCount, STATGROUP_GeometryCache);

/** Resource array to pass  */
class GEOMETRYCACHE_API FGeomCacheVertexResourceArray : public FResourceArrayInterface
{
public:
	FGeomCacheVertexResourceArray(void* InData, uint32 InSize);

	virtual const void* GetResourceData() const override;
	virtual uint32 GetResourceDataSize() const override;
	virtual void Discard() override;
	virtual bool IsStatic() const override;
	virtual bool GetAllowCPUAccess() const override;
	virtual void SetAllowCPUAccess(bool bInNeedsCPUAccess) override;

private:
	void* Data;
	uint32 Size;
};

/** Vertex Buffer */
class GEOMETRYCACHE_API FGeomCacheVertexBuffer : public FVertexBuffer
{
public:
	TArray<FDynamicMeshVertex> Vertices;

	virtual void InitRHI() override;

	void UpdateRHI();
};

/** Index Buffer */
class GEOMETRYCACHE_API FGeomCacheIndexBuffer : public FIndexBuffer
{
public:
	TArray<int32> Indices;

	virtual void InitRHI() override;

	void UpdateRHI();
};

/** Vertex Factory */
class GEOMETRYCACHE_API FGeomCacheVertexFactory : public FLocalVertexFactory
{
public:

	FGeomCacheVertexFactory();

	/** Init function that should only be called on render thread. */
	void Init_RenderThread(const FGeomCacheVertexBuffer* VertexBuffer);

	/** Init function that can be called on any thread, and will do the right thing (enqueue command if called on main thread) */
	void Init(const FGeomCacheVertexBuffer* VertexBuffer);
};

class GEOMETRYCACHE_API FGeomCacheTrackProxy
{
public:
	/** MeshData storing information used for rendering this Track */
	FGeometryCacheMeshData* MeshData;

	/** Material applied to this Track */
	TArray<UMaterialInterface*> Materials;
	/** Vertex buffer for this Track */
	FGeomCacheVertexBuffer VertexBuffer;
	/** Index buffer for this Track */
	FGeomCacheIndexBuffer IndexBuffer;
	/** Vertex factory for this Track */
	FGeomCacheVertexFactory VertexFactory;
	/** World Matrix for this Track */
	FMatrix WorldMatrix;
};

/** Procedural mesh scene proxy */
class GEOMETRYCACHE_API FGeometryCacheSceneProxy : public FPrimitiveSceneProxy
{
public:
	// QQ interfaces/comments
	FGeometryCacheSceneProxy(class UGeometryCacheComponent* Component);

	virtual ~FGeometryCacheSceneProxy();

	virtual void GetDynamicMeshElements(const TArray<const FSceneView*>& Views, const FSceneViewFamily& ViewFamily, uint32 VisibilityMap, FMeshElementCollector& Collector) const override;

	virtual FPrimitiveViewRelevance GetViewRelevance(const FSceneView* View);

	virtual bool CanBeOccluded() const override;

	virtual uint32 GetMemoryFootprint(void) const;

	uint32 GetAllocatedSize(void) const;

	/** Update world matrix for specific section */
	void UpdateSectionWorldMatrix(const int32 SectionIndex, const FMatrix& WorldMatrix);
	/** Update vertex buffer for specific section */
	void UpdateSectionVertexBuffer(const int32 SectionIndex, FGeometryCacheMeshData* MeshData );
	/** Update index buffer for specific section */
	void UpdateSectionIndexBuffer(const int32 SectionIndex, const TArray<int32>& Indices);

	/** Clears the Sections array*/
	void ClearSections();
	
private:	
	FMaterialRelevance MaterialRelevance;

	/** Array of Track Proxies */
	TArray<FGeomCacheTrackProxy*> Sections;
};