#ifndef _OspTree_H__
#define _OspTree_H__

#include <stack>

#include "Mesh.h"
#include "Containers.h"
#include "Statistics.h"
#include "VssRay.h"
#include "RayInfo.h"
#include "gzstream.h"
#include "SubdivisionCandidate.h"


namespace GtpVisibilityPreprocessor {

class ViewCellLeaf;
class Plane3;
class AxisAlignedBox3;
class Ray;
class ViewCellsStatistics;
class ViewCellsManager;
class MergeCandidate;
class Beam;
class ViewCellsTree;
class Environment;
class VspInterior;
class VspLeaf;
class VspNode;
class KdNode;
class KdInterior;
class KdLeaf;
class OspTree;
class KdIntersectable;
class KdTree;
class VspTree;
class KdTreeStatistics;
class SubdivisionCandidate;


/** View space partition statistics.
*/
class OspTreeStatistics: public StatisticsBase
{
public:
	// total number of nodes
	int nodes;
	// number of splits
	int splits[3];
	
	// maximal reached depth
	int maxDepth;
	// minimal depth
	int minDepth;
	
	// max depth nodes
	int maxDepthNodes;
	// minimum depth nodes
	int minDepthNodes;
	// max depth nodes
	int minPvsNodes;
	// minimum area nodes
	int minProbabilityNodes;
	/// nodes termination because of max cost ratio;
	int maxCostNodes;
	// max number of objects per node
	int maxObjectRefs;
	int objectRefs;
	/// samples contributing to pvs
	int contributingSamples;
	/// sample contributions to pvs
	int sampleContributions;
	/// largest pvs
	int maxPvs;
	/// number of invalid leaves
	int invalidLeaves;
	/// accumulated number of rays refs
	int accumRays;
	/// potentially visible objects from this leaf
	int pvs;

	// accumulated depth (used to compute average)
	int accumDepth;

	// Constructor
	OspTreeStatistics() 
	{
		Reset();
	}

	int Nodes() const {return nodes;}
	int Interior() const { return nodes / 2; }
	int Leaves() const { return (nodes / 2) + 1; }
	
	// TODO: computation wrong
	double AvgDepth() const { return accumDepth / (double)Leaves();}; 
	

	void Reset() 
	{
		nodes = 0;
		for (int i = 0; i < 3; ++ i)
			splits[i] = 0;
		
		maxDepth = 0;
		minDepth = 99999;
		accumDepth = 0;
        pvs = 0;
		maxDepthNodes = 0;
		minPvsNodes = 0;
	
		minProbabilityNodes = 0;
		maxCostNodes = 0;

		contributingSamples = 0;
		sampleContributions = 0;

		maxPvs = 0;
		invalidLeaves = 0;
		objectRefs = 0;

		maxObjectRefs = 0;
	}


	void Print(ostream &app) const;

	friend ostream &operator<<(ostream &s, const OspTreeStatistics &stat) 
	{
		stat.Print(s);
		return s;
	} 
};


typedef map<KdNode *, KdIntersectable *> KdIntersectableMap;


/** View Space Partitioning tree.
*/
class OspTree 
{
	friend class ViewCellsParseHandlers;
	friend class HierarchyManager;

public:
	
	/** Additional data which is passed down the BSP tree during traversal.
	*/
	class OspTraversalData
	{  
	public:
		/// the current node
		KdLeaf *mNode;
		/// current depth
		int mDepth;
		/// rays piercing this node
		RayInfoContainer *mRays;
		/// the probability that this node contains view point
		float mProbability;
		/// the bounding box of the node
		AxisAlignedBox3 mBoundingBox;
		/// pvs size
		float mRenderCost;
		/// how often this branch has missed the max-cost ratio
		int mMaxCostMisses;
		// current axis
		int mAxis;
		// current priority
		float mPriority;


		OspTraversalData():
		mNode(NULL),
		mRays(NULL),
		mDepth(0),
		mRenderCost(0),
		mProbability(0.0),
		mMaxCostMisses(0), 
		mPriority(0),
		mAxis(0)
		{}
		
		OspTraversalData(KdLeaf *node, 
						 const int depth,
                         RayInfoContainer *rays,
						 const float rc,
						 const float p,
						 const AxisAlignedBox3 &box):
		mNode(node), 
		mDepth(depth),
		mRays(rays),
		mRenderCost(rc),
		mProbability(p),
		mBoundingBox(box),
		mMaxCostMisses(0),
		mPriority(0),
		mAxis(0)
		{}

		OspTraversalData(const int depth, 
			RayInfoContainer *rays,
			const AxisAlignedBox3 &box): 
		mNode(NULL), 
		mDepth(depth),
		mRays(rays),
		mRenderCost(0),
		mProbability(0),
		mMaxCostMisses(0),
		mAxis(0),
		mBoundingBox(box)
		{}

		/** Returns cost of the traversal data.
		*/
		float GetCost() const
		{
			//cout << mPriority << endl;
			return mPriority;
		}

		/// deletes contents and sets them to NULL
		void Clear()
		{
			DEL_PTR(mRays);
		}


		friend bool operator<(const OspTraversalData &a, const OspTraversalData &b)
		{
			return a.GetCost() < b.GetCost();
		}
    };

	/** Candidate for a view space split.
	*/
	class OspSubdivisionCandidate: public SubdivisionCandidate
	{  
	public:
		static OspTree* sOspTree;

		/// the current split plane
		AxisAlignedPlane mSplitPlane;
		/// parent data
		OspTraversalData mParentData;
		
		OspSubdivisionCandidate(const OspTraversalData &tData): mParentData(tData)
		{};

		int Type() const { return OBJECT_SPACE; }
	
		void EvalPriority()
		{
			sOspTree->EvalSubdivisionCandidate(*this);	
		}

		bool GlobalTerminationCriteriaMet() const
		{
			return sOspTree->GlobalTerminationCriteriaMet(mParentData);
		}


		OspSubdivisionCandidate(const AxisAlignedPlane &plane, const OspTraversalData &tData): 
		mSplitPlane(plane), mParentData(tData)
		{}
	};

	/** Struct for traversing line segment.
	*/
	struct LineTraversalData 
	{
		KdNode *mNode;
		Vector3 mExitPoint;
		
		float mMaxT;
    
		LineTraversalData () {}
		LineTraversalData (KdNode *n, const Vector3 &p, const float maxt):
		mNode(n), mExitPoint(p), mMaxT(maxt) {}
	};

	/** Default constructor creating an empty tree.
	*/ 
	OspTree();

	/** Copies tree from a kd tree.
	*/
	OspTree(const KdTree &kdTree);

	/** Default destructor.
	*/
	~OspTree();

	/** Returns tree statistics.
	*/
	const OspTreeStatistics &GetStatistics() const; 
  
	/** Returns bounding box of the specified node.
	*/
	AxisAlignedBox3 GetBoundingBox(KdNode *node) const;

	/** Returns list of leaves with pvs smaller than
		a certain threshold.
		@param onlyUnmailed if only the unmailed leaves should be considered
		@param maxPvs the maximal pvs of a leaf to be added (-1 means unlimited)
	*/
	
	void CollectLeaves(vector<KdLeaf *> &leaves) const;

	/** Returns bounding box of the whole tree (= bbox of root node)
	*/
	AxisAlignedBox3 GetBoundingBox()const;

	/** Returns root of the view space partitioning tree.
	*/
	KdNode *GetRoot() const;

	/** Collects the leaf view cells of the tree
		@param viewCells returns the view cells 
	*/
	void CollectViewCells(ViewCellContainer &viewCells, bool onlyValid) const;

	/** A ray is cast possible intersecting the tree.
		@param the ray that is cast.
		@returns the number of intersections with objects stored in the tree.
	*/
	int CastRay(Ray &ray);

	/** finds neighbouring leaves of this tree node.
	*/
	int FindNeighbors(KdLeaf *n, 
					  vector<VspLeaf *> &neighbors, 
					  const bool onlyUnmailed) const;

	/** Returns random leaf of BSP tree.
		@param halfspace defines the halfspace from which the leaf is taken.
	*/
	KdLeaf *GetRandomLeaf(const Plane3 &halfspace);

	/** Returns random leaf of BSP tree.
		@param onlyUnmailed if only unmailed leaves should be returned.
	*/
	KdLeaf *GetRandomLeaf(const bool onlyUnmailed = false);

	/** Returns epsilon of this tree.
	*/
	float GetEpsilon() const;

	/** Casts line segment into the tree.
		@param origin the origin of the line segment
		@param termination the end point of the line segment
		@returns view cells intersecting the line segment.
	*/
    int CastLineSegment(const Vector3 &origin,
						const Vector3 &termination,
						ViewCellContainer &viewcells);
		
	/** Sets pointer to view cells manager.
	*/
	void SetViewCellsManager(ViewCellsManager *vcm);

	/** Writes tree to output stream
	*/
	bool Export(OUT_STREAM &stream);

	/** Returns or creates a new intersectable for use in a kd based pvs.
		The OspTree is responsible for destruction of the intersectable.
	*/
	KdIntersectable *GetOrCreateKdIntersectable(KdNode *node);

	/** Collects rays stored in the leaves.
	*/
	void CollectRays(VssRayContainer &rays);

	/** Intersects box with the tree and returns the number of intersected boxes.
		@returns number of view cells found
	*/
	int ComputeBoxIntersections(const AxisAlignedBox3 &box, 
								ViewCellContainer &viewCells) const;


	/** Returns kd leaf the point pt lies in, starting from root.
	*/
	KdLeaf *GetLeaf(const Vector3 &pt, KdNode *root = NULL) const;


	ViewCellsTree *GetViewCellsTree() const { return mViewCellsTree; }

	void SetViewCellsTree(ViewCellsTree *vt) { mViewCellsTree = vt; }

	float EvalRenderCost(const VssRayContainer &myrays);
	float EvalLeafCost(const OspTraversalData &tData);

	/** Adds this objects to the kd leaf objects.
		@warning: Can corrupt the tree
	*/
	void InsertObjects(KdNode *node, const ObjectContainer &objects);

	/** Add the leaf to the pvs of the view cell.
	*/
	bool AddLeafToPvs(
		KdLeaf *leaf, 
		ViewCell *vc, 
		const float pdf, 
		float &contribution);

protected:

	// --------------------------------------------------------------
	// For sorting objects
	// --------------------------------------------------------------
	struct SortableEntry
	{
		/** There is a 3th "event" for rays which intersect a
			box in the middle. These "events" don't induce a change in
			pvs size, but may induce a change in view cell volume.
		*/
		enum EType 
		{
			BOX_MIN,
			BOX_MAX,
			BOX_INTERSECT
		};

		int mType;
		//int mPvs;
		float mPos;
		VssRay *mRay;
		
		Intersectable *mObject;

		SortableEntry() {}

		SortableEntry(const int type,
			//const float pvs, 
			const float pos,
			Intersectable *obj,
			VssRay *ray):
		mType(type), 
		//mPvs(pvs), 
		mPos(pos), 
		mObject(obj),
		mRay(ray)
		{}

		bool operator<(const SortableEntry &b) const 
		{
			return mPos < b.mPos;
		}
	};

 
	/** faster evaluation of split plane cost for kd axis aligned cells.
	*/
	float EvalLocalSplitCost(const OspTraversalData &data,
							 const AxisAlignedBox3 &box,
							 const int axis,
							 const float &position,
							 float &pFront,
							 float &pBack) const;

	/** Evaluates candidate for splitting.
	*/
	void EvalSubdivisionCandidate(OspSubdivisionCandidate &splitData);

	/** Computes priority of the traversal data and stores it in tData.
	*/
	void EvalPriority(OspTraversalData &tData) const;

	/** Evaluates render cost decrease of next split.
	*/
	float EvalRenderCostDecrease(const AxisAlignedPlane &candidatePlane,
								 const OspTraversalData &data,
								 float &normalizedOldRenderCost) const;


	/** Collects view cells in the subtree under root.
	*/
	void CollectViewCells(KdNode *root, 
						  bool onlyValid, 
						  ViewCellContainer &viewCells,
						  bool onlyUnmailed = false) const;

	/** Evaluates tree stats in the BSP tree leafs.
	*/
	void EvaluateLeafStats(const OspTraversalData &data);

	/** Subdivides node using a best split priority queue.
	    @param tQueue the best split priority queue
		@param splitCandidate the candidate for the next split
		@param globalCriteriaMet if the global termination criteria were already met
		@returns new root of the subtree
	*/
	KdNode *Subdivide(SplitQueue &tQueue,
					  SubdivisionCandidate *splitCandidate,
					  const bool globalCriteriaMet);
	
	/** Subdivides leaf.
		@param leaf the leaf to be subdivided
		
		@param polys the polygons to be split
		@param frontPolys returns the polygons in front of the split plane
		@param backPolys returns the polygons in the back of the split plane
		
		@param rays the polygons to be filtered
		@param frontRays returns the polygons in front of the split plane
		@param backRays returns the polygons in the back of the split plane

		@returns the root of the subdivision
	*/
	KdInterior *SubdivideNode(
		const AxisAlignedPlane &splitPlane,
		const OspTraversalData &tData,
		OspTraversalData &frontData,
		OspTraversalData &backData);

	void SplitObjects(KdLeaf *leaf,
					  const AxisAlignedPlane & splitPlane,
					  const ObjectContainer &objects,
					  ObjectContainer &front,
					  ObjectContainer &back);

	/** does some post processing on the objects in the new child leaves.
	*/
	void ProcessMultipleRefs(KdLeaf *leaf) const;

	/** Sorts split candidates for cost heuristics using axis aligned splits.
		@param node the current node
		@param axis the current split axis
	*/
	void SortSubdivisionCandidates(const OspTraversalData &data,
							 const int axis, 
							 float minBand, 
							 float maxBand);

	/** Computes best cost for axis aligned planes.
	*/
	float EvalLocalCostHeuristics(const OspTraversalData &tData,
		const AxisAlignedBox3 &box,
		const int axis,
		float &position,
		int &objectsFront,
		int &objectsBack);

	/** Subdivides the rays into front and back rays according to the split plane.
		
		@param plane the split plane
		@param rays contains the rays to be split. The rays are 
			   distributed into front and back rays.
		@param frontRays returns rays on the front side of the plane
		@param backRays returns rays on the back side of the plane
		
		@returns the number of splits
	*/
	int SplitRays(const AxisAlignedPlane &plane,
		RayInfoContainer &rays, 
		RayInfoContainer &frontRays, 
		RayInfoContainer &backRays) const;

	int FilterRays(KdLeaf *leaf, const RayInfoContainer &rays, RayInfoContainer &filteredRays);

	/** Adds the object to the pvs of the front and back leaf with a given classification.

		@param obj the object to be added
		@param cf the ray classification regarding the split plane
		@param frontPvs returns the PVS of the front partition
		@param backPvs returns the PVS of the back partition
	
	*/
	void UpdateObjPvsContri(Intersectable *obj, 
					 const int cf, 
					 float &frontPvs, 
					 float &backPvs, 
					 float &totalPvs) const;
	
	/** Returns true if tree can be terminated.
	*/
	bool LocalTerminationCriteriaMet(const OspTraversalData &data) const;

	/** Returns true if global tree can be terminated.
	*/
	bool GlobalTerminationCriteriaMet(const OspTraversalData &data) const;

	/** Selects an axis aligned for the next split.
		@returns cost for this split
	*/
	float SelectSplitPlane(
		const OspTraversalData &tData,
		AxisAlignedPlane &plane);
	
	/** Propagates valid flag up the tree.
	*/
	void PropagateUpValidity(KdNode *node);

	/** Writes the node to disk
		@note: should be implemented as visitor.
	*/
	void ExportNode(KdNode *node, OUT_STREAM &stream);

	/** Returns estimated memory usage of tree.
	*/
	float GetMemUsage() const;

	/** Evaluate the contributions of view cell volume of the left and the right view cell.
	*/
	void EvalRayContribution(
		KdLeaf *leaf,
		const VssRay &ray, 
		float &renderCost);
	
	void EvalViewCellContribution(
		KdLeaf *leaf, 
		ViewCell *viewCell,
		float &renderCost);

	/** Evaluates the influence on the pvs of the event.
		@param ve the visibility event
		@param pvsLeft updates the left pvs
		@param rightPvs updates the right pvs
	*/
	void EvalHeuristicsContribution(KdLeaf *leaf,
		const SortableEntry &ci,
		float &renderCost,
		ViewCellContainer &touchedViewCells);

	/** Prepares objects for the cost heuristics.
		@returns pvs size of the node
	*/
	float PrepareHeuristics(
		const OspTraversalData &tData, 
		ViewCellContainer &touchedViewCells);

	/** Prepares heuristics for a particular ray.
	*/
	void PrepareHeuristics(
		const VssRay &ray, 
		ViewCellContainer &touchedViewCells);

	/** Prepares construction for vsp and osp trees.
	*/
	void ComputeBoundingBox(const ObjectContainer &objects);

	void CollectDirtyCandidates(OspSubdivisionCandidate *sc,
		vector<SubdivisionCandidate *> &dirtyList);

	/** Collect view cells which see this kd leaf.
	*/
	void CollectViewCells(KdLeaf *leaf, 
		ViewCellContainer &viewCells);

	/** Rays will be clipped to the bounding box.
	*/
	void PreprocessRays(
		KdLeaf *root, 
		const VssRayContainer &sampleRays,
		RayInfoContainer &rays);

	/** Reads parameters from environment singleton.
	*/
	void ReadEnvironment();

	/** Returns true if the specified ray end points is inside the kd leaf.
		@param isTermination if origin or termination point should be checked
	*/
	bool EndPointInsideNode(KdLeaf *leaf, VssRay &ray, bool isTermination) const;

	void AddViewCellVolumeContri(
		ViewCell *vc, 
		float &frontVol, 
		float &backVol,
		float &frontAndBackVol) const;

	/** Classifies and mail view cell with respect to the heuristics contribution.
		Set view cell mail box according to it's influence on 
		front (0), back (1) and front / back node (2).
	*/
	void  MailViewCell(ViewCell *vc, const int cf) const;

	int ClassifyRay(VssRay *ray, KdLeaf *leaf, const AxisAlignedPlane &plane) const;

	void EvalSubdivisionStats(const SubdivisionCandidate &tData);

	void AddSubdivisionStats(const int viewCells,
		const float renderCostDecr,
		const float totalRenderCost);

	void EvalViewCellsForHeuristics(const VssRay &ray, 
		float &volLeft, 
		float &volRight);

	float EvalViewCellsVolume(KdLeaf *leaf, const RayInfoContainer &rays) const;
	
	int RemoveParentViewCellsPvs(KdLeaf *leaf, 
									  const RayInfoContainer &rays
									  ) const;

	int UpdateViewCellsPvs(KdLeaf *leaf, const RayInfoContainer &rays) const;
int CheckViewCellsPvs(KdLeaf *leaf, 
							   const RayInfoContainer &rays) const;
	bool AddViewCellToObjectPvs(
		Intersectable *obj,
		ViewCell *vc, 
		float &contribution,
		bool onlyMailed) const;

	int ClassifyRays(
		const RayInfoContainer &rays, 
		KdLeaf *leaf, 
		const AxisAlignedPlane &plane,
		RayInfoContainer &frontRays,
		RayInfoContainer &backRays) const;

	void CollectTouchedViewCells(
		const RayInfoContainer &rays, 
		ViewCellContainer &touchedViewCells) const;

	void AddObjectContribution(
		KdLeaf *leaf,
		Intersectable * obj,
		ViewCellContainer &touchedViewCells,
		float &renderCost);

	void SubtractObjectContribution(
		KdLeaf *leaf,
		Intersectable * obj,
		ViewCellContainer &touchedViewCells,
		float &renderCost);

	SubdivisionCandidate *PrepareConstruction(
		const VssRayContainer &sampleRays,
		const ObjectContainer &objects,
		RayInfoContainer &rays);


protected:
	
	/// pointer to the hierarchy of view cells
	ViewCellsTree *mViewCellsTree;

	VspTree *mVspTree;

	/// The view cells manager
	ViewCellsManager *mViewCellsManager;

	/// candidates for placing split planes during cost heuristics
	vector<SortableEntry> *mSubdivisionCandidates;

	/// Pointer to the root of the tree
	KdNode *mRoot;
		
	/// Statistics for the object space partition
	OspTreeStatistics mOspStats;
	
	/// box around the whole view domain
	AxisAlignedBox3 mBoundingBox;


	//-- local termination

	/// maximal possible depth
	int mTermMaxDepth;
	/// mininum probability
	float mTermMinProbability;
	/// minimal number of objects
	int mTermMinObjects;
	/// maximal contribution per ray
	float mTermMaxRayContribution;
	/// maximal acceptable cost ratio
	float mTermMaxCostRatio;
	/// tolerance value indicating how often the max cost ratio can be failed
	int mTermMissTolerance;


	//-- global criteria

	float mTermMinGlobalCostRatio;
	int mTermGlobalCostMissTolerance;
	int mGlobalCostMisses;

	/// maximal number of view cells
	int mTermMaxLeaves;
	/// maximal tree memory
	float mMaxMemory;
	/// the tree is out of memory
	bool mOutOfMemory;


	//-- split heuristics based parameters
	
	bool mUseCostHeuristics;
	/// balancing factor for PVS criterium
	float mCtDivCi;	
	/// if only driving axis should be used for split
	bool mOnlyDrivingAxis;
	
	/// current time stamp (used for keeping split history)
	int mTimeStamp;
	// if rays should be stored in leaves
	bool mStoreRays;

	/// epsilon for geometric comparisons
	float mEpsilon;

	/// subdivision stats output file
	ofstream  mSubdivisionStats;
	/// keeps track of cost during subdivision
	float mTotalCost;
	/// keeps track of overall pvs size during subdivision
	int mTotalPvsSize;
	/// number of currenly generated view cells
	int mCreatedLeaves;

	/// represents min and max band for sweep
	float mSplitBorder;

	/// weight between  render cost decrease and node render cost
	float mRenderCostDecreaseWeight;

	/// stores the kd node intersectables used for pvs
	KdIntersectableMap mKdIntersectables;


private:

	bool mCopyFromKdTree;
};


}

#endif