#ifndef _ViewCellsManager_H__
#define _ViewCellsManager_H__

#include "Ray.h"
#include "VssRay.h"
#include "Containers.h"

class ViewCell;
class Intersectable;
class RenderSimulator;
class Mesh;
struct Triangle3;
class SimulationStatistics;
class BspTree;
class KdTree;
class VspKdTree;
class VspBspTree;
class KdNode;
class KdLeaf;
class VspKdTree;
class AxisAlignedBox3;
class BspLeaf;

/**
	Manages different higher order operations on the view cells.
*/
class ViewCellsManager
{

public:
	
	/// view cell container types
	enum {BSP, KD, VSP_KD, VSP_BSP};

	/** Constructor taking the maximal number of samples used for construction
	*/
	ViewCellsManager(const int constructionSamples);

	ViewCellsManager();

	~ViewCellsManager();

	/** Constructs view cell container with a given number of samples.
	*/
	virtual int Construct(const ObjectContainer &objects, 
						  const VssRayContainer &rays,
						  AxisAlignedBox3 *sceneBbox = NULL) = 0;

	/** Computes sample contributions of the rays to the view cells PVS.
	
		@param rays bundle of rays used to find intersections with view cells and 
		adding the contribution
		@param castRays true if ray should be cast to gain the information, false if rays
		already hold the view cells intersection information and need not be recast.
		@param sampleContributions returns the number of sample contributions
		@param contributingSamples returns the number of contributingSamples
	*/
	void  ComputeSampleContributions(const RayContainer &rays, 
									 int &sampleContributions,
									 int &contributingSamples,
									 const bool castRays = true);


	/** Computes sample contribution of a simgle ray to the view cells PVS.
		@param ray finds intersections with view cells and holds the contribution
		@param castRay true if ray should be cast to gain the information, false if ray
		is already holding the information and need not be recast.

		@returns number of sample contributions
	*/
	virtual int ComputeSampleContributions(Ray &ray, const bool castRay = true) = 0;

	/** Prints out statistics of the view cells.
	*/
	virtual void PrintStatistics(ostream &s) const = 0;

	/** Post processes view cells givem´a number of rays.
	*/
	virtual int PostProcess(const ObjectContainer &objects, 
							const RayContainer &rays) = 0;

	/** Show visualization of the view cells.
	*/
	virtual void Visualize(const ObjectContainer &objects,
						   const RayContainer &sampleRays) = 0;

	/** type of the view cell container.
	*/
	virtual int GetType() const = 0;

	/** Simulates rendering with the given view cell partition.
		@returns render time statistics
	*/
	SimulationStatistics SimulateRendering() const;

	/** Load the input viewcells. The input viewcells should be given as a collection
		of meshes. Each mesh is assume to form a bounded polyhedron defining the interior of
		the viewcell. The method then builds a BSP tree of these view cells.
		
		@param filename file to load
		@return true on success
    */
    bool LoadViewCells(const string filename);

	/** Constructs view cell from base triangle. The ViewCell is extruded along the normal vector.
		@param the base triangle
		@param the height of the newly created view cell
	*/
	ViewCell *ExtrudeViewCell(const Triangle3 &baseTri, const float height) const;

	/** Merges two view cells.
		@note the piercing rays of the front and back will be ordered	
		@returns new view cell based on the merging.
	*/
	ViewCell *MergeViewCells(ViewCell &front, ViewCell &back) const;
	
	/** Generates view cell of type specified by this manager
	*/
	virtual ViewCell *GenerateViewCell(Mesh *mesh = NULL) const;

	/** Adds a new view cell to the list of predefined view cells.
	*/
	void AddViewCell(ViewCell *viewCell);

	/** Derive view cells from objects.
	*/
	void DeriveViewCells(const ObjectContainer &objects, 
						 ViewCellContainer &viewCells, 
						 const int maxViewCells) const;

	/** Sets maximal number of samples used for the 
		construction of the view cells.
	*/
	void SetVisualizationSamples(const int visSamples);

	/** Sets maximal number of samples used for the visualization of the view cells.
	*/
	void SetConstructionSamples(const int constructionSamples);

	/** Sets maximal number of samples used for the post processing of the view cells.
	*/
	void SetPostProcessSamples(const int postProcessingSamples);

	/** See set.
	*/
	int GetVisualizationSamples() const;

	/** See set.
	*/
	int GetConstructionSamples() const;

	/** See set.
	*/
	int GetPostProcessSamples() const;

	/** Returns true if view cells wer already constructed.
	*/
	virtual bool ViewCellsConstructed() const = 0;
		

protected:
	
	

	/** Initialises the render time simulator.
	*/
	void InitRenderSimulator();
	/////////////////////

	
	/// the view cell corresponding to unbounded space
	ViewCell *mUnbounded;

	/// Simulates rendering
	RenderSimulator *mRenderSimulator;

	/// Loaded view cells
	ViewCellContainer mViewCells;

	/// maximum number of samples taken for construction of the view cells
	int mConstructionSamples;
	int mPostProcessSamples;
	int mVisualizationSamples;

	//-- thresholds used for view cells merge
	int mMinPvsDif;
	int mMinPvs;
	int mMaxPvs;
};



/**
	Manages different higher order operations on the view cells.
*/
class BspViewCellsManager: public ViewCellsManager
{

public:

	BspViewCellsManager(BspTree *tree, int constructionSamples);

	int Construct(const ObjectContainer &objects, 
				  const VssRayContainer &rays,
				  AxisAlignedBox3 *sceneBbox);

	int ComputeSampleContributions(Ray &ray, const bool castRay = false);

	int PostProcess(const ObjectContainer &objects, 
					const RayContainer &rays);

	void Visualize(const ObjectContainer &objects,
				   const RayContainer &sampleRays);

	int GetType() const;
	
	ViewCell *GenerateViewCell(Mesh *mesh = NULL) const;

	bool ViewCellsConstructed() const;

	void PrintStatistics(ostream &s) const;

protected:

	/** Merges view cells front and back leaf view cell.
	*/
	bool MergeBspLeafViewCells(BspLeaf *front, BspLeaf *back) const;

	/** Returns true if front and back leaf should be merged.
	*/
	bool ShouldMerge(BspLeaf *front, BspLeaf *back) const;

	/// the BSP tree.
	BspTree *mBspTree;


private:


	/** Exports visualization of the BSP splits.
	*/
	void ExportSplits(const ObjectContainer &objects, const RayContainer &sampleRays);

	/** Exports visualization of the BSP PVS.
	*/
	void ExportBspPvs(const ObjectContainer &objects, const RayContainer &sampleRays);

};

/**
	Manages different higher order operations on the KD type view cells.
*/
class KdViewCellsManager: public ViewCellsManager
{

public:

	KdViewCellsManager(KdTree *tree);

	int Construct(const ObjectContainer &objects, 
				  const VssRayContainer &rays,
				  AxisAlignedBox3 *sceneBbox);

	int CastRay(const Ray &ray);

	int PostProcess(const ObjectContainer &objects, 
					const RayContainer &rays);

	void Visualize(const ObjectContainer &objects,
				   const RayContainer &sampleRays);

	int GetType() const;

	bool ViewCellsConstructed() const;


	/** Prints out statistics of this approach.
	*/
	virtual void PrintStatistics(ostream &s) const;

protected:

	 KdNode *GetNodeForPvs(KdLeaf *leaf);

	 int ComputeSampleContributions(Ray &ray, const bool castRay = true);

	 /// the BSP tree.
	 KdTree *mKdTree;

	 /// depth of the KD tree nodes with represent the view cells
	 int mKdPvsDepth;
};

/**
	Manages different higher order operations on the view cells 
	for vsp kd tree view cells.
*/
class VspKdViewCellsManager: public ViewCellsManager
{

public:

	VspKdViewCellsManager(VspKdTree *vspKdTree, int constructionSamples);

	int Construct(const ObjectContainer &objects, 
				  const VssRayContainer &rays,
				  AxisAlignedBox3 *sceneBbox);

	int ComputeSampleContributions(Ray &ray, const bool castRay = true);

	int PostProcess(const ObjectContainer &objects, 
					const RayContainer &rays);

	void Visualize(const ObjectContainer &objects,
				   const RayContainer &sampleRays);

	int GetType() const;
	
	bool ViewCellsConstructed() const;

	virtual void PrintStatistics(ostream &s) const;

protected:

	/// the BSP tree.
	VspKdTree *mVspKdTree;
};



/**
	Manages different higher order operations on the view cells.
*/
class VspBspViewCellsManager: public ViewCellsManager
{

public:

	VspBspViewCellsManager(VspBspTree *tree, int constructionSamples);

	int Construct(const ObjectContainer &objects, 
				  const VssRayContainer &rays,
				  AxisAlignedBox3 *sceneBbox);

	int ComputeSampleContributions(Ray &ray, const bool castRay = false);

	int PostProcess(const ObjectContainer &objects, 
					const RayContainer &rays);

	void Visualize(const ObjectContainer &objects,
				   const RayContainer &sampleRays);

	int GetType() const;
	
	ViewCell *GenerateViewCell(Mesh *mesh = NULL) const;

	bool ViewCellsConstructed() const;

	void PrintStatistics(ostream &s) const;

protected:

	/** Merges view cells front and back leaf view cell.
	*/
	bool MergeVspBspLeafViewCells(BspLeaf *front, BspLeaf *back) const;

	/** Returns true if front and back leaf should be merged.
	*/
	bool ShouldMerge(BspLeaf *front, BspLeaf *back) const;

	/// the view space partition BSP tree.
	VspBspTree *mVspBspTree;


private:


	/** Exports visualization of the BSP splits.
	*/
	void ExportSplits(const ObjectContainer &objects, const RayContainer &sampleRays);

	/** Exports visualization of the BSP PVS.
	*/
	void ExportBspPvs(const ObjectContainer &objects, const RayContainer &sampleRays);

};

#endif