/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    itkMovingHistogramMorphologicalGradientImageFilter.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even 
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef __itkMovingHistogramMorphologicalGradientImageFilter_h
#define __itkMovingHistogramMorphologicalGradientImageFilter_h

#include "itkMovingHistogramImageFilter.h"
#include <map>

namespace itk {

namespace Function {
template <class TInputPixel>
class MorphologicalGradientHistogram
{
public:
  MorphologicalGradientHistogram()
    {
    m_UseVectorBasedAlgorithm = UseVectorBasedAlgorithm();
    if( m_UseVectorBasedAlgorithm )
      { initVector(); }
    }
  ~MorphologicalGradientHistogram(){}

  MorphologicalGradientHistogram * Clone() const
    {
    MorphologicalGradientHistogram * result = new MorphologicalGradientHistogram();
    result->m_Map = this->m_Map;
    result->m_Vector = this->m_Vector;
    result->m_Min = this->m_Min;
    result->m_Max = this->m_Max;
    result->m_Count = this->m_Count;
    return result;
    }

  inline void AddBoundary() {}

  inline void RemoveBoundary() {}

  inline void AddPixel( const TInputPixel &p )
    {
    if( m_UseVectorBasedAlgorithm )
      { AddPixelVector( p ); }
    else
      { AddPixelMap( p ); }
    }

  inline void RemovePixel( const TInputPixel &p )
    {
    if( m_UseVectorBasedAlgorithm )
      { RemovePixelVector( p ); }
    else
      { RemovePixelMap( p ); }
    }

  inline TInputPixel GetValue( const TInputPixel & )
    {
    if( m_UseVectorBasedAlgorithm )
      { return GetValueVector(); }
    else
      { return GetValueMap(); }
    }


  static inline bool UseVectorBasedAlgorithm()
    {
    // bool, short and char are acceptable for vector based algorithm: they do not require
    // too much memory. Other types are not usable with that algorithm
    return typeid(TInputPixel) == typeid(unsigned char)
        || typeid(TInputPixel) == typeid(signed char)
        || typeid(TInputPixel) == typeid(unsigned short)
        || typeid(TInputPixel) == typeid(signed short)
        || typeid(TInputPixel) == typeid(bool);
    }

  bool m_UseVectorBasedAlgorithm;
  
  //
  // the map based algorithm
  //

  typedef std::map< TInputPixel, unsigned long > MapType;

  inline void AddPixelMap( const TInputPixel &p )
    { m_Map[ p ]++; }

  inline void RemovePixelMap( const TInputPixel &p )
    { m_Map[ p ]--; }

  inline TInputPixel GetValueMap()
    {
    // clean the map
    typename MapType::iterator mapIt = m_Map.begin();
    while( mapIt != m_Map.end() )
      {
      if( mapIt->second == 0 )
        { 
        // this value must be removed from the histogram
        // The value must be stored and the iterator updated before removing the value
        // or the iterator is invalidated.
        TInputPixel toErase = mapIt->first;
        mapIt++;
        m_Map.erase(toErase);
        }
      else
        {
        mapIt++;
        }
      }

    // and return the value
    if( !m_Map.empty() )
      { return m_Map.rbegin()->first - m_Map.begin()->first; }
    return 0;
    }

  MapType m_Map;


  //
  // the vector based algorithm
  //

  inline void initVector()
    {
    // initialize members need for the vector based algorithm
    m_Vector.resize( static_cast<int>( NumericTraits< TInputPixel >::max() - NumericTraits< TInputPixel >::NonpositiveMin() + 1 ), 0 );
    m_Max = NumericTraits< TInputPixel >::NonpositiveMin();
    m_Min = NumericTraits< TInputPixel >::max();
    m_Count = 0;
    }

  inline void AddPixelVector( const TInputPixel &p )
    {
    m_Vector[ static_cast<int>( p - NumericTraits< TInputPixel >::NonpositiveMin() ) ]++;
    if( p > m_Max )
      { m_Max = p; }
    if( p < m_Min )
      { m_Min = p; }
    m_Count++;
    }

  inline void RemovePixelVector( const TInputPixel &p )
    {
    m_Vector[ static_cast<int>( p - NumericTraits< TInputPixel >::NonpositiveMin() ) ]--;
    m_Count--;
    if( m_Count > 0 )
      {
      while( m_Vector[ static_cast<int>( m_Max - NumericTraits< TInputPixel >::NonpositiveMin() ) ] == 0 )
        { m_Max--; }
      while( m_Vector[ static_cast<int>( m_Min - NumericTraits< TInputPixel >::NonpositiveMin() ) ] == 0 )
        { m_Min++; }
      }
    else
      {
      m_Max = NumericTraits< TInputPixel >::NonpositiveMin();
      m_Min = NumericTraits< TInputPixel >::max();
      }
    }

  inline TInputPixel GetValueVector()
    {
    if( m_Count > 0 )
      { return m_Max - m_Min; }
    else
      { return NumericTraits< TInputPixel >::Zero; }
    }

  std::vector<unsigned long> m_Vector;
  TInputPixel                m_Min;
  TInputPixel                m_Max;
  unsigned long              m_Count;


};
} // end namespace Function

/**
 * \class MovingHistogramMorphologicalGradientImageFilter
 * \brief Morphological gradients enhance the variation of pixel
 * intensity in a given neighborhood.
 *
 * Morphological gradient is described in Chapter 3.8.1 of Pierre
 * Soille's book  "Morphological Image Analysis: Principles and
 * Applications", Second Edition, Springer, 2003.
 * 
 * \author Gaetan Lehmann. Biologie du Developpement et de la Reproduction, INRA de Jouy-en-Josas, France.
 *
 * \ingroup ImageEnhancement  MathematicalMorphologyImageFilters
 */


template<class TInputImage, class TOutputImage, class TKernel>
class ITK_EXPORT MovingHistogramMorphologicalGradientImageFilter : 
    public MovingHistogramImageFilter<TInputImage, TOutputImage, TKernel,
      typename  Function::MorphologicalGradientHistogram< typename TInputImage::PixelType > >
{
public:
  /** Standard class typedefs. */
  typedef MovingHistogramMorphologicalGradientImageFilter Self;
  typedef MovingHistogramImageFilter<TInputImage, TOutputImage, TKernel,
      typename  Function::MorphologicalGradientHistogram< typename TInputImage::PixelType > >  Superclass;
  typedef SmartPointer<Self>        Pointer;
  typedef SmartPointer<const Self>  ConstPointer;
  
  /** Standard New method. */
  itkNewMacro(Self);  

  /** Runtime information support. */
  itkTypeMacro(MovingHistogramMorphologicalGradientImageFilter, 
               ImageToImageFilter);
  
  /** Image related typedefs. */
  typedef TInputImage                                 InputImageType;
  typedef TOutputImage                                OutputImageType;
  typedef typename TInputImage::RegionType            RegionType;
  typedef typename TInputImage::SizeType              SizeType;
  typedef typename TInputImage::IndexType             IndexType;
  typedef typename TInputImage::PixelType             PixelType;
  typedef typename TInputImage::OffsetType            OffsetType;
  typedef typename Superclass::OutputImageRegionType  OutputImageRegionType;
  typedef typename TOutputImage::PixelType            OutputPixelType;

  typedef Function::MorphologicalGradientHistogram< PixelType > HistogramType;


  /** Image related typedefs. */
  itkStaticConstMacro(ImageDimension, unsigned int,
                      TInputImage::ImageDimension);
                      

  /** Return true if the vector based algorithm is used, and
   * false if the map based algorithm is used */
  static bool GetUseVectorBasedAlgorithm()
    { return Function::MorphologicalGradientHistogram< ITK_TYPENAME TInputImage::PixelType >::UseVectorBasedAlgorithm(); }
  
protected:
  MovingHistogramMorphologicalGradientImageFilter() {};
  ~MovingHistogramMorphologicalGradientImageFilter() {};


private:
  MovingHistogramMorphologicalGradientImageFilter(const Self&); //purposely not implemented
  void operator=(const Self&); //purposely not implemented

}; // end of class

} // end namespace itk
  
#endif