// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.
#pragma once

#include "CoreMinimal.h"
#include "UObject/ObjectMacros.h"
#include "UObject/Object.h"
#include "GeometryCacheTrack.generated.h"

struct FGeometryCacheMeshData;

/** Base class for GeometryCache tracks, stores matrix animation data and implements functionality for it */
UCLASS(collapsecategories, hidecategories = Object, MinimalAPI, BlueprintType, config = Engine)
class UGeometryCacheTrack : public UObject
{
	GENERATED_UCLASS_BODY()

	virtual ~UGeometryCacheTrack();
	
	//~ Begin UObject Interface.
	virtual void Serialize(FArchive& Ar) override;
	virtual void GetResourceSizeEx(FResourceSizeEx& CumulativeResourceSize) override;
	//~ End UObject Interface
			
	/**
	* UpdateMatrixData
	*
	* @param Time - (Elapsed)Time to check against
	* @param bLooping - Whether or not the animation should be played on a loop
	* @param InOutMatrixSampleIndex - Hold the MatrixSampleIndex and will be updated if changed according to the Elapsed Time
	* @param OutWorldMatrix - Will hold the new WorldMatrix if the SampleIndex changed
	* @return const bool
	*/
	virtual const bool UpdateMatrixData(const float Time, const bool bLooping, int32& InOutMatrixSampleIndex, FMatrix& OutWorldMatrix);

	/**
	* UpdateMeshData
	*
	* * @param Time - (Elapsed)Time to check against
	* @param bLooping - Whether or not the animation should be played on a loop
	* @param InOutMeshSampleIndex - Hold the MeshSampleIndex and will be updated if changed according to the Elapsed Time
	* @param OutVertices - Will hold the new VertexData if the SampleIndex changed
	* @return const bool
	*/
	virtual const bool UpdateMeshData(const float Time, const bool bLooping, int32& InOutMeshSampleIndex, FGeometryCacheMeshData*& OutMeshData );

	/**
	* SetMatrixSamples, Set the Matrix animation Samples 
	*
	* @param Matrices - Array of Matrices
	* @param SampleTimes - Array of SampleTimes
	* @return void
	*/
	virtual void SetMatrixSamples(const TArray<FMatrix>& Matrices, const TArray<float>& SampleTimes);

	/**
	* GetMaxSampleTime, returns the time for the last sample can be considered as the total animation leght
	*
	* @return const float
	*/
	virtual const float GetMaxSampleTime() const;
	
	/**
	* GetNumMaterials, total number of materials inside this track (depends on batches)
	*
	* @return const uint32
	*/
	const uint32 GetNumMaterials() const { return NumMaterials; }

protected:
	/**
	* FindSampleIndexFromTime uses binary search to find the closest index to Time inside Samples
	*
	* @param SampleTimes - Array of Sample times used for the search
	* @param Time - Time for which the closest index has to be found
	* @param bLooping - Whether or not we should fmod Time according to the last entry in SampleTimes
	* @return const uint32
	*/
	const uint32 FindSampleIndexFromTime(const TArray<float>& SampleTimes, const float Time, const bool bLooping);

	/** Matrix sample data, both FMatrix and time*/
	TArray<FMatrix> MatrixSamples;	
	TArray<float> MatrixSampleTimes;

	/** Number of materials for this track*/
	uint32 NumMaterials;
};