#ifndef ROOT_TKDTree
#define ROOT_TKDTree

#ifndef ROOT_TObject
#include "TObject.h"
#endif

#include "TMath.h"


template <typename Index, typename Value> class TKDTree : public TObject
{
public:
	
  TKDTree();
  TKDTree(Index npoints, Index ndim, UInt_t bsize, Value **data);
  ~TKDTree();
  // Get indexes of left and right daughter nodes
  Int_t GetLeft(Int_t inode)  const    {return inode*2+1;}
  Int_t GetRight(Int_t inode) const    {return (inode+1)*2;}
  Int_t GetParent(Int_t inode) const  {return inode/2;}
  //  
  // getters
  Index*  GetPointsIndexes(Int_t node) const {
    if(node < fNnodes) return 0x0;
    Int_t offset = (node >= fCrossNode) ? (node-fCrossNode)*fBucketSize : fOffset+(node-fNnodes)*fBucketSize;
    return &fIndPoints[offset];
  }
  UChar_t GetNodeAxis(Int_t id) const {return (id < 0 || id >= fNnodes) ? 0 : fAxis[id];}
  Value   GetNodeValue(Int_t id) const {return (id < 0 || id >= fNnodes) ? 0 : fValue[id];}
  Int_t   GetNNodes() const {return fNnodes;}
  Value*  GetBoundaries();
  Value*  GetBoundary(const Int_t node);
  static  Int_t   GetIndex(Int_t row, Int_t collumn){return collumn+(1<<row);}
  static void GetCoord(Int_t index, Int_t &row, Int_t &collumn){for (row=0; index>=(16<<row);row+=4); for (; index>=(2<<row);row++);collumn= index-(1<<row);};
  Bool_t  FindNearestNeighbors(const Value *point, const Int_t kNN, Index *&i, Value *&d);
  Index   FindNode(const Value * point);
  void    FindPoint(Value * point, Index &index, Int_t &iter);
  void    FindInRangeA(Value * point, Value * delta, Index *res , Index &npoints,Index & iter, Int_t bnode);
  void    FindInRangeB(Value * point, Value * delta, Index *res , Index &npoints,Index & iter, Int_t bnode);
  void    FindBNodeA(Value * point, Value * delta, Int_t &inode);
  Bool_t  IsTerminal(Index inode) const {return (inode>=fNnodes);}
  Value   KOrdStat(Index ntotal, Value *a, Index k, Index *index) const;
  void    MakeBoundaries(Value *range = 0x0);
  void    SetData(Index npoints, Index ndim, UInt_t bsize, Value **data);
  void    Spread(Index ntotal, Value *a, Index *index, Value &min, Value &max) const;
  

 protected:
  void            Build();  // build tree
  
 private:
  TKDTree(const TKDTree &); // not implemented
  TKDTree<Index, Value>& operator=(const TKDTree<Index, Value>&); // not implemented
  void            CookBoundaries(const Int_t node, Bool_t left);
  
  
 protected:
  Bool_t  fDataOwner;  //! Toggle ownership of the data
  Int_t   fNnodes;     // size of node array
  Index   fNDim;       // number of dimensions
  Index   fNDimm;      // dummy 2*fNDim
  Index   fNpoints;    // number of multidimensional points
  Index   fBucketSize; // limit statistic for nodes 
  UChar_t *fAxis;      //[fNnodes] nodes cutting axis
  Value   *fValue;     //[fNnodes] nodes cutting value
  //
  Value	  *fRange;     //[fNDimm] range of data for each dimension
  Value   **fData;     //! data points
  Value	  *fBoundaries;//! nodes boundaries - check class doc
  
  // kNN related data
 protected:
  Int_t   fkNNdim;     //! current kNN arrays allocated dimension
  Index   *fkNN;       //! k nearest neighbors indexes
  Value   *fkNNdist;   //! k nearest neighbors distances
  Value   *fDistBuffer;//! working space for kNN
  Index   *fIndBuffer; //! working space for kNN
  
 private:
  Index   *fIndPoints; //! array of points indexes
  Int_t   fRowT0;      //! smallest terminal row
  Int_t   fCrossNode;  //! cross node
  Int_t   fOffset;     //! offset in fIndPoints
  
  ClassDef(TKDTree, 1)  // KD tree
};


typedef TKDTree<Int_t, Double_t> TKDTreeID;
typedef TKDTree<Int_t, Float_t> TKDTreeIF;

// Test functions:
TKDTreeIF *  TKDTreeTestBuild();



//_________________________________________________________________
template <typename  Index, typename Value>
void TKDTree<Index, Value>::FindBNodeA(Value *point, Value *delta, Int_t &inode){
  //
  // find the smallest node covering the full range - start
  //
  inode =0; 
  for (;inode<fNnodes;){
    if (TMath::Abs(point[fAxis[inode]] - fValue[inode])<delta[fAxis[inode]]) break;
    inode = (point[fAxis[inode]] < fValue[inode]) ? (inode*2)+1: (inode*2)+2;
  }
}

//_________________________________________________________________
template <typename  Index, typename Value>
Value* TKDTree<Index, Value>::GetBoundaries()
{
  // Get the boundaries
	if(!fBoundaries) MakeBoundaries();
	return fBoundaries;
}

//_________________________________________________________________
template <typename  Index, typename Value>
Value* TKDTree<Index, Value>::GetBoundary(const Int_t node)
{
  // Get a boundary
	if(!fBoundaries) MakeBoundaries();
	return &fBoundaries[node*2*fNDim];
}

#endif