#ifndef __PVS_H
#define __PVS_H

#include <map>

class KdNode;
class BspNode;
class Ray;
class Intersectable;


template<typename T>
struct LtSample {
    bool operator()(const T a, const T b) const
    {
		return a < b;
	} 
};

//typedef std::map<T *, PvsData<T>, LtSample<T>> PvsMap<T>;

template<typename T> 
struct PvsData {
  int mVisibleSamples;
  PvsData<T>() {}
  PvsData<T>(const int samples): mVisibleSamples(samples) {}
};

template<typename T>
class Pvs
{
public:
    Pvs(): mSamples(0), mEntries() {}
	int mSamples;

	int Compress() {return 0;}
	int GetSize() {return (int)mEntries.size();}
	bool Empty() {return mEntries.size() == 0;}
	void Merge(const Pvs<T> &a, const Pvs<T> &b);

	PvsData<T> *Find(T sample);
	int AddSample(T sample);

	void GetData(const int index,
	       T &entry,
	       PvsData<T> &data);
	std::map<T, PvsData<T>, LtSample<T> > mEntries;
};

template <typename T>
void Pvs<T>::Merge(const Pvs<T> &a, const Pvs<T> &b)
{
	//std::merge(a.mEntries.begin(), a.mEntries.end(), 
	//	       b.mEntries.begin(), b.mEntries.end(), mEntries.begin());
}

template <typename T>
PvsData<T> *Pvs<T>::Find(T sample)
{
  std::map<T, PvsData<T>, LtSample<T> >::iterator i = mEntries.find(sample);
  if (i != mEntries.end()) {
    return &(*i).second;
  } else
    return NULL;
}

template <typename T>
void Pvs<T>::GetData(const int index,
	       T &entry,
	       PvsData<T> &data)
{
  std::map<T, PvsData<T>, LtSample<T> >::iterator i = mEntries.begin();
  for (int k = 0; k != index && i != mEntries.end(); i++, k++);

  entry = (*i).first;
  data = (*i).second;
}

template <typename T>
int Pvs<T>::AddSample(T sample)
{
	int result;
	PvsData<T> *data = Find(sample);

	if (data) 
	{
		data->mVisibleSamples ++;
		result = 0;
	
	} 
	else 
	{
		mEntries[sample] = PvsData<T>(1);
		result = 1;
	}

	return  result;
}

/** Class instantiating the Pvs template for kd tree nodes.
*/
class KdPvs: public Pvs<KdNode *>
{
	int Compress();
};

typedef std::map<KdNode *, PvsData<KdNode *>, LtSample<KdNode *> > KdPvsMap;
typedef std::map<Intersectable *, PvsData<Intersectable *>, LtSample<Intersectable *> > ViewCellPvsMap;
typedef PvsData<Intersectable *> ViewCellPvsData;
typedef PvsData<KdNode *> KdPvsData;
//typedef Pvs<KdNode *> KdPvs;
typedef Pvs<Intersectable *> ViewCellPvs;

#endif