// ================================================================
// $Id$
// ****************************************************************
// 
// Initial coding by
/**
   @author Jiri Bittner
*/

#ifndef __VSSTREE_H__
#define __VSSTREE_H__

// Standard headers
#include <iomanip>
#include <vector>
#include <functional>
#include <stack>


// User headers
#include "VssRay.h"
#include "AxisAlignedBox3.h"
#include "Statistics.h"
#include "Ray.h"

namespace GtpVisibilityPreprocessor {

#define USE_KDNODE_VECTORS 1
#define _RSS_STATISTICS
#define _RSS_TRAVERSAL_STATISTICS



// --------------------------------------------------------------
// Static statistics for kd-tree search
// --------------------------------------------------------------
class VssStatistics :
  public StatisticsBase
{
public:  
  // total number of nodes
  int nodes;
  // number of splits along each of the axes
  int splits[7];
  // totals number of rays
  int rays;
  // initial size of the pvs
  int initialPvsSize;
  // total number of query domains
  int queryDomains;
  // total number of ray references
  int rayRefs;

  // max depth nodes
  int maxDepthNodes;
  // max depth nodes
  int minPvsNodes;
  int minRaysNodes;
  // max ray contribution nodes
  int maxRayContribNodes;
  // max depth nodes
  int minSizeNodes;
  int maxCostRatioNodes;

  // max number of rays per node
  int maxRayRefs;
  // number of dynamically added ray refs
  int addedRayRefs;
  // number of dynamically removed ray refs
  int removedRayRefs;
  
  // Constructor
  VssStatistics() {
    Reset();
  }

  int Nodes() const {return nodes;}
  int Interior() const { return nodes/2; }
  int Leaves() const { return (nodes/2) + 1; }

  void Reset() {
    nodes = 0;
    for (int i=0; i<7; i++)
      splits[i] = 0;
    rays = queryDomains = 0;
    rayRefs = 0;
    maxDepthNodes = 0;
    minPvsNodes = 0;
    minRaysNodes = 0;
    maxRayRefs = 0;
    addedRayRefs = removedRayRefs = 0;
	initialPvsSize = 0;
	maxRayContribNodes = 0;
	minSizeNodes = 0;
	maxCostRatioNodes = 0;
  }

  
  void
  Print(ostream &app) const;

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




class VssTreeInterior;


// --------------------------------------------------------------
// KD-tree node - abstract class
// --------------------------------------------------------------
class VssTreeNode
{
public:

#define USE_FIXEDPOINT_T 0

  struct RayInfo
  {
	// pointer to the actual ray
	VssRay *mRay;
	
	// endpoints  - do we need them?
#if USE_FIXEDPOINT_T
	short mMinT, mMaxT;
#else
	float mMinT, mMaxT;
#endif
	
	RayInfo():mRay(NULL) {}
	
	RayInfo(VssRay *r):mRay(r), mMinT(0),
#if USE_FIXEDPOINT_T
#define FIXEDPOINT_ONE 0x7FFE
					   //			  mMaxT(0xFFFF)
					   mMaxT(FIXEDPOINT_ONE)
#else
	  mMaxT(1.0f)
#endif
	{}
	
	RayInfo(VssRay *r,
			const float _min,
			const float _max
			):mRay(r) {
	  SetMinT(_min);
	  SetMaxT(_max);
	}
	
	RayInfo(VssRay *r,
			const short _min,
			const float _max
			):mRay(r), mMinT(_min) {
	  SetMaxT(_max);
	}
	
	RayInfo(VssRay *r,
			const float _min,
			const short _max
			):mRay(r), mMaxT(_max) {
	  SetMinT(_min);
	}

	enum {
	  SOURCE_RAY = 0,
	  TERMINATION_RAY,
	  PASSING_RAY,
	  CONTAINED_RAY
	};
	
	int GetRayClass() const {
		
	  bool startsBefore = GetMinT() > 0.0f;
	  bool terminatesAfter = GetMaxT() < 1.0f;
		
	  if (startsBefore && terminatesAfter)
		return PASSING_RAY;

	  if (!startsBefore && !terminatesAfter)
		return CONTAINED_RAY;
		
	  if (!startsBefore)
		return SOURCE_RAY;
		
	  return TERMINATION_RAY;
	}
	
	friend bool operator<(const RayInfo &a, const RayInfo &b) {
	  return a.mRay < b.mRay;
	}
  
	
	float ExtrapOrigin(const int axis) const {
	  return mRay->GetOrigin(axis) + GetMinT()*mRay->GetDir(axis);
	}
	
	float ExtrapTermination(const int axis) const {
	  return mRay->GetOrigin(axis) + GetMaxT()*mRay->GetDir(axis);
	}

	Vector3 Extrap(const float t) const {
	  return mRay->Extrap(t);
	}
	
#if USE_FIXEDPOINT_T
	float GetMinT () const { return mMinT/(float)(FIXEDPOINT_ONE); }
	float GetMaxT () const { return mMaxT/(float)(FIXEDPOINT_ONE); }
	
	void SetMinT (const float t) {
	  mMinT = (short) (t*(float)(FIXEDPOINT_ONE));
	}
	
	void SetMaxT (const float t) {
	  mMaxT = (short) (t*(float)(FIXEDPOINT_ONE));
	  mMaxT++;
	  //      if (mMaxT!=0xFFFF)
	  //	mMaxT++;
	}
#else
	float GetMinT () const { return mMinT; }
	float GetMaxT () const { return mMaxT; }
	
	void SetMinT (const float t) { mMinT = t; }
	void SetMaxT (const float t) { mMaxT = t; }
#endif 


	int ComputeRayIntersection(const int axis,
							   const float position,
							   float &t
							   ) const {
		
#if 1
	  // intersect the ray with the plane
	  float denom = mRay->GetDir(axis);
    
	  if (fabs(denom) < 1e-20)
		//if (denom == 0.0f)
		return (mRay->GetOrigin(axis) > position) ? 1 : -1;
    
	  t = (position - mRay->GetOrigin(axis))/denom;

	  if (t < GetMinT())
		return (denom > 0) ? 1 : -1;

	  if (t > GetMaxT())
		return (denom > 0) ? -1 : 1;

	  return 0;
#else
	  // subbdivision based only on the origin
	  t = 0;
	  float rpos = mRay->GetOrigin(axis);
	  return (rpos < position) ? -1 : 1;

#endif
	}


  };

  void GetSampleData(const bool isTerminaton, 
				  Vector3 &pt, 
				  Intersectable **obj,
				  KdNode **node) const;

  typedef vector<RayInfo> RayInfoContainer;
	
  enum { EInterior, ELeaf };

  /////////////////////////////////
  // The actual data goes here
  
  // link to the parent
  VssTreeInterior *parent;

  enum {SPLIT_X=0, SPLIT_Y, SPLIT_Z, SPLIT_DIRX, SPLIT_DIRY, SPLIT_DIRZ};
  
  // splitting axis
  char axis;
	
  // depth
  unsigned char depth;
  
  //  short depth;
  //
  /////////////////////////////////
  
  inline VssTreeNode(VssTreeInterior *p);

  
  virtual ~VssTreeNode() {};
  virtual int Type() const  = 0;
  

  bool IsLeaf() const { return axis == -1; }
  
  virtual void Print(ostream &s) const = 0;

  virtual int GetAccessTime() {
    return 0x7FFFFFF;
  }

  
	
};

// --------------------------------------------------------------
// KD-tree node - interior node
// --------------------------------------------------------------
class VssTreeInterior :
  public VssTreeNode
{
public:
  // plane in local modelling coordinates
  float position;

  // pointers to children
  VssTreeNode *back, *front;

  // the bbox of the node
  AxisAlignedBox3 bbox;

  // the bbox of the node
  AxisAlignedBox3 dirBBox;
  
  // data for caching
  long accesses;
  long lastAccessTime;
  
  VssTreeInterior(VssTreeInterior *p):VssTreeNode(p),
									  back(NULL),
									  front(NULL),
									  accesses(0),
									  lastAccessTime(-1)
  { }

  virtual int GetAccessTime() {
    return lastAccessTime;
  }

  void SetupChildLinks(VssTreeNode *b, VssTreeNode *f) {
    back = b;
    front = f;
    b->parent = f->parent = this;
  }

  void ReplaceChildLink(VssTreeNode *oldChild, VssTreeNode *newChild) {
    if (back == oldChild)
      back = newChild;
    else
      front = newChild;
  }

  virtual int Type() const  { return EInterior; }
  
  virtual ~VssTreeInterior() {
    if (back)
      delete back;
    if (front)
      delete front;
  }
  
  virtual void Print(ostream &s) const {
    if (axis == 0)
      s<<"x ";
    else
      if (axis == 1)
		s<<"y ";
      else
		s<<"z ";
    s<<position<<" ";
    back->Print(s);
    front->Print(s);
  }

  
	
  int ComputeRayIntersection(const RayInfo &rayData,
							 float &t
							 ) {
	return rayData.ComputeRayIntersection(axis, position, t);
  }

};


// --------------------------------------------------------------
// KD-tree node - leaf node
// --------------------------------------------------------------
class VssTreeLeaf :
  public VssTreeNode
{
private:
  int mPvsSize;
public:
  static int mailID;
  int mailbox;
  
  RayInfoContainer rays;
  int mPassingRays;
	
  bool mValidPvs;
  float mEntropyImportance;
  
	
  VssTreeLeaf(VssTreeInterior *p,
			  const int nRays
			  ):VssTreeNode(p), rays(), mPvsSize(0), mPassingRays(0), mValidPvs(false) {
    rays.reserve(nRays);
  }
  
  virtual ~VssTreeLeaf() { }

  virtual int Type() const  { return ELeaf; }

  virtual void Print(ostream &s) const {
    s<<endl<<"L: r="<<(int)rays.size()<<endl;
  };
  
  void AddRay(const RayInfo &data) {
	mValidPvs = false;
    rays.push_back(data);
    data.mRay->Ref();
	if (data.GetRayClass() == RayInfo::PASSING_RAY)
	  mPassingRays++;
  }
	
  int GetPvsSize() const {
	return mPvsSize;
  }

  void SetPvsSize(const int s) {
	mPvsSize = s;
	mValidPvs = true;
  }

  void
  UpdatePvsSize();

  float
  ComputePvsEntropy();
  
  float
  ComputeRayLengthEntropy();
  
  float
  ComputeRayTerminationEntropy();
  
  void
  ComputeEntropyImportance();

  void Mail() { mailbox = mailID; }
  static void NewMail() { mailID++; }
  bool Mailed() const { return mailbox == mailID; }
  
  bool Mailed(const int mail) {
    return mailbox >= mailID + mail;
  }

  float GetAvgRayContribution() const {
	return GetPvsSize()/((float)rays.size() + Limits::Small);
  }

  float GetImportance() const;
  
  float GetSqrRayContribution() const {
	return sqr(GetPvsSize()/((float)rays.size() + Limits::Small));
  }
  
  // comparator for the 
  struct less_contribution : public
  binary_function<const VssTreeLeaf *, const VssTreeLeaf *, bool> {
	
	bool operator()(const VssTreeLeaf * a, const VssTreeLeaf *b) {
	  return a->GetAvgRayContribution() < b->GetAvgRayContribution();
	}
  };
  
  struct greater_contribution : public
  binary_function<const VssTreeLeaf *, const VssTreeLeaf *, bool> {
	
	bool operator()(const VssTreeLeaf * a, const VssTreeLeaf *b) {
	  return a->GetAvgRayContribution() > b->GetAvgRayContribution();
	}
  };
  
  friend bool GreaterContribution(const VssTreeLeaf * a, const VssTreeLeaf *b) {
	return a->GetAvgRayContribution() > b->GetAvgRayContribution();
  }
  
};

// Inline functions
inline
VssTreeNode::VssTreeNode(VssTreeInterior *p):
  parent(p), axis(-1), depth(p ? p->depth + 1 : 0) {}



// ---------------------------------------------------------------
// Main LSDS search class
// ---------------------------------------------------------------
class VssTree
{
  struct TraversalData
  {  
    VssTreeNode *node;
    AxisAlignedBox3 bbox;
    int depth;
    float priority;
    
    TraversalData() {}

    TraversalData(VssTreeNode *n, const float p):
      node(n), priority(p)
    {}

    TraversalData(VssTreeNode *n,
				  const AxisAlignedBox3 &b,
				  const int d):
      node(n), bbox(b), depth(d) {}
    
		
    // comparator for the 
    struct less_priority : public
    binary_function<const TraversalData, const TraversalData, bool> {
			
      bool operator()(const TraversalData a, const TraversalData b) {
		return a.priority < b.priority;
      }
      
    };

    //    ~TraversalData() {}
    //    TraversalData(const TraversalData &s):node(s.node), bbox(s.bbox), depth(s.depth) {}
    
    friend bool operator<(const TraversalData &a,
						  const TraversalData &b) {
      //      return a.node->queries.size() < b.node->queries.size();
      VssTreeLeaf *leafa = (VssTreeLeaf *) a.node;
      VssTreeLeaf *leafb = (VssTreeLeaf *) b.node;
#if 0
	  return
		leafa->rays.size()*a.bbox.GetVolume()
		<
		leafb->rays.size()*b.bbox.GetVolume();
#endif
#if 0
	  return
		leafa->GetPvsSize()*a.bbox.GetVolume()
		<
		leafb->GetPvsSize()*b.bbox.GetVolume();
#endif
#if 0
	  return
		leafa->GetPvsSize()
		<
		leafb->GetPvsSize();
#endif
#if 0
	  return
		leafa->GetPvsSize()/(leafa->rays.size()+1)
		>
		leafb->GetPvsSize()/(leafb->rays.size()+1);
#endif
#if 1
	  return
		leafa->GetPvsSize()*leafa->rays.size()
		<
		leafb->GetPvsSize()*leafb->rays.size();
#endif
    }
  };
  
  // simplified data for ray traversal only...

  struct RayTraversalData {
    
    VssTreeNode::RayInfo rayData;
    VssTreeNode *node;
    
    RayTraversalData() {}
    RayTraversalData(VssTreeNode *n,
					 const VssTreeNode::RayInfo &data):
      rayData(data), node(n) {}
  };
	
public:
  /////////////////////////////
  // The core pointer
  VssTreeNode *root;
  
  /////////////////////////////
  // Basic properties

  // total number of nodes of the tree
  int nodes;
  // axis aligned bounding box of the scene
  AxisAlignedBox3 bbox;

  // axis aligned bounding box of directions
  AxisAlignedBox3 dirBBox;
  
  /////////////////////////////
  // Construction parameters

  // epsilon used for the construction
  float epsilon;

  // ratio between traversal and intersection costs
  float ct_div_ci;
  // max depth of the tree
  int termMaxDepth;
  // minimal ratio of the volume of the cell and the query volume
  float termMinSize;

  // minimal pvs per node to still get subdivided
  int termMinPvs;

  // minimal ray number per node to still get subdivided
  int termMinRays;
	
  // maximal cost ration to subdivide a node
  float termMaxCostRatio;
	
  // maximal contribution per ray to subdivide the node
  float termMaxRayContribution;

	
  // randomized construction
  bool randomize;
  
  // type of the splitting to use fo rthe tree construction
  enum {ESplitRegular, ESplitHeuristic, ESplitHybrid };
  int splitType;

  bool mSplitUseOnlyDrivingAxis;
  
  // use ray space subdivision instead of view space subdivision
  bool mUseRss;

  // interleave directional and spatial splits based on their costs
  // if false directional splits are only performed after spatial splits
  bool mInterleaveDirSplits;

  // depth at which directional splits are performed if mInterleaveDirSplits is false
  int mDirSplitDepth;
  
  // maximal size of the box on which the refdir splitting can be performed
  // (relative to the scene bbox
  float refDirBoxMaxSize;
  
  // maximum alovable memory in MB
  float maxTotalMemory;

  // maximum alovable memory for static kd tree in MB
  float maxStaticMemory;

  // this is used during the construction depending
  // on the type of the tree and queries...
  float maxMemory;


  // minimal acess time for collapse
  int accessTimeThreshold;

  // minimal depth at which to perform collapse
  int minCollapseDepth;

  
  // reusable array of split candidates
  vector<SortableEntry> *splitCandidates;
  /////////////////////////////

  VssStatistics stat;
	
  
  VssTree();
  virtual ~VssTree();

  virtual void
  Construct(
			VssRayContainer &rays,
			AxisAlignedBox3 *forcedBoundingBox = NULL
			);
	
  // incemental construction
  virtual void UpdateRays(VssRayContainer &remove,
						  VssRayContainer &add
						  );

  virtual void AddRays(
					   VssRayContainer &add
					   )
  {
	VssRayContainer remove;
	UpdateRays(remove, add);
  }

  
	
  VssTreeNode *
  Locate(const Vector3 &v);
	
  VssTreeNode *
  SubdivideNode(VssTreeLeaf *leaf,
				const AxisAlignedBox3 &box,
				AxisAlignedBox3 &backBox,
				AxisAlignedBox3 &frontBox
				);
	
  VssTreeNode *
  Subdivide(const TraversalData &tdata);
	
  int
  SelectPlane(VssTreeLeaf *leaf,
			  const AxisAlignedBox3 &box,
			  float &position,
			  int &raysBack,
			  int &raysFront,
			  int &pvsBack,
			  int &pvsFront
			  );

  void
  SortSubdivisionCandidates(
					  VssTreeLeaf *node,
					  const int axis
					  );
	
  
  // return memory usage in MB
  float GetMemUsage() const {
    return 
      (sizeof(VssTree) +
       stat.Leaves()*sizeof(VssTreeLeaf) +
       stat.Interior()*sizeof(VssTreeInterior) +
       stat.rayRefs*sizeof(VssTreeNode::RayInfo))/(1024.0f*1024.0f);
  }
	
  float GetRayMemUsage() const {
    return 
      stat.rays*(sizeof(VssRay))/(1024.0f*1024.0f);
  }
  

  float
  BestCostRatio(
				VssTreeLeaf *node,
				int &axis,
				float &position,
				int &raysBack,
				int &raysFront,
				int &pvsBack,
				int &pvsFront
				);
	
  float
  EvalCostRatio(
				VssTreeLeaf *node,
				const int axis,
				const float position,
				int &raysBack,
				int &raysFront,
				int &pvsBack,
				int &pvsFront
				);

  float
  EvalCostRatioHeuristic(
						 VssTreeLeaf *node,
						 const int axis,
						 float &position,
						 int &raysBack,
						 int &raysFront,
						 int &pvsBack,
						 int &pvsFront
						 );

  float
  GetCostRatio(
			   VssTreeLeaf *leaf,
			   const int axis,
			   const float position,
			   const int raysBack,
			   const int raysFront,
			   const int pvsBack,
			   const int pvsFront
			   );

  AxisAlignedBox3 GetBBox(const VssTreeNode *node) const {
    if (node->parent == NULL)
      return bbox;

    if (!node->IsLeaf())
      return ((VssTreeInterior *)node)->bbox;

    if (node->parent->axis >= 3)
      return node->parent->bbox;
      
    AxisAlignedBox3 box(node->parent->bbox);
    if (node->parent->front == node)
      box.SetMin(node->parent->axis, node->parent->position);
    else
      box.SetMax(node->parent->axis, node->parent->position);
    return box;
  }

  AxisAlignedBox3 GetDirBBox(const VssTreeNode *node) const {

    if (node->parent == NULL)
      return dirBBox;
    
    if (!node->IsLeaf() )
      return ((VssTreeInterior *)node)->dirBBox;

    if (node->parent->axis < 3)
      return node->parent->dirBBox;
    
    AxisAlignedBox3 dBBox(node->parent->dirBBox);

    if (node->parent->front == node)
      dBBox.SetMin(node->parent->axis - 3, node->parent->position);
    else
      dBBox.SetMax(node->parent->axis - 3, node->parent->position);
    return dBBox;
  }
  
  int
  ReleaseMemory(const int time);

  int
  CollapseSubtree(VssTreeNode *node, const int time);

  void
  CountAccess(VssTreeInterior *node, const long time) {
    node->accesses++;
    node->lastAccessTime = time;
  }

  VssTreeNode *
  SubdivideLeaf(
				VssTreeLeaf *leaf
				);

  void
  RemoveRay(VssRay *ray,
			vector<VssTreeLeaf *> *affectedLeaves,
			const bool removeAllScheduledRays
			);

  //  void
  //  AddRay(VssRay *ray);
  void
  AddRay(VssTreeNode::RayInfo &info);
  
  void
  TraverseInternalNode(
					   RayTraversalData &data,
					   stack<RayTraversalData> &tstack);

  void
  EvaluateLeafStats(const TraversalData &data);


  int
  GetRootPvsSize() const {
	return GetPvsSize(bbox);
  }
  
  int
  GetPvsSize(const AxisAlignedBox3 &box) const;

  void
  GetRayContributionStatistics(
							   float &minRayContribution,
							   float &maxRayContribution,
							   float &avgRayContribution
							   );

  int
  GenerateRays(const float ratioPerLeaf,
			   SimpleRayContainer &rays);

  int
  GenerateRays(const int numberOfRays,
			   const int numberOfLeaves,
			   SimpleRayContainer &rays);
		
  float
  GetAvgPvsSize();

  int
  UpdateSubdivision();

  bool
  TerminationCriteriaSatisfied(VssTreeLeaf *leaf);

  void
  CollectLeaves(vector<VssTreeLeaf *> &leaves);

  bool
  ClipRay(
		  VssTreeNode::RayInfo &rayInfo,
		  const AxisAlignedBox3 &box
		  );

  VssTreeNode *GetRoot() const { return root; }

  bool
  ValidLeaf(VssTreeLeaf *leaf) const;

  void
  GenerateLeafRays(VssTreeLeaf *leaf,
				   const int numberOfRays,
				   SimpleRayContainer &rays);

  int
  CollectRays(VssRayContainer &rays,
			  const int number);

  int
  CollectRays(VssRayContainer &rays);
  
};

};

#endif // __LSDS_KDTREE_H__