#ifndef __JTOOLS__JMULTIPDF__
#define __JTOOLS__JMULTIPDF__

#include "JTools/JTransformableMultiFunction.hh"
#include "JTools/JTransformableMultiHistogram.hh"
#include "JTools/JHistogramMap.hh"
#include "JTools/JToolsToolkit.hh"
#include "JIO/JObjectBinaryIO.hh"


/**
 * \author mdejong
 */

namespace JTOOLS {}
namespace JPP { using namespace JTOOLS; }

namespace JTOOLS {

  using JIO::JObjectBinaryIO;

  
  /**
   * General purpose class for multi-dimensional probability density function (PDF).
   *
   * This class is a simple wrapper around the JTransformableMultiFunction class
   * to properly convert a multi-dimensional histogram to a multi-dimensional PDF.
   * In this, the histogram contents in each bin are divided by the summed weight 
   * of the multi-dimensional histogram and the width (c.q. area) of the multi-dimensional bin.
   */
  template<class JFunction_t,
	   class JMaplist_t,
           class JDistance_t = JDistance<typename JFunction_t::argument_type> >
  class JMultiPDF :
    public JTransformableMultiFunction<JFunction_t, JMaplist_t, JDistance_t>,
    public JObjectBinaryIO< JMultiPDF<JFunction_t, JMaplist_t, JDistance_t> >
  {
  public:

    typedef JTransformableMultiFunction<JFunction_t, 
					JMaplist_t,
					JDistance_t>                            transformablemultifunction_type;

    enum { NUMBER_OF_DIMENSIONS = transformablemultifunction_type::NUMBER_OF_DIMENSIONS };

    typedef JFunction_t                                                         function_type;

    typedef typename transformablemultifunction_type::value_type                value_type;
    typedef typename transformablemultifunction_type::argument_type             argument_type;
    typedef typename transformablemultifunction_type::supervisor_type           supervisor_type;

    typedef typename transformablemultifunction_type::abscissa_type             abscissa_type;
    typedef typename transformablemultifunction_type::ordinate_type             ordinate_type;
    typedef typename transformablemultifunction_type::result_type               result_type;

    typedef typename transformablemultifunction_type::const_iterator            const_iterator;
    typedef typename transformablemultifunction_type::const_reverse_iterator    const_reverse_iterator;
    typedef typename transformablemultifunction_type::iterator                  iterator;
    typedef typename transformablemultifunction_type::reverse_iterator          reverse_iterator;

    typedef typename transformablemultifunction_type::super_iterator            super_iterator;
    typedef typename transformablemultifunction_type::super_const_iterator      super_const_iterator;

    typedef JMultiMapTransformer<JMapLength<JMaplist_t>::value, argument_type>  transformer_type;
    typedef typename transformer_type::array_type                               array_type;

    using transformablemultifunction_type::insert;


    /**
     * Default constructor.
     */
    JMultiPDF()
    {}


    /**
     * Constructor.
     *
     * \param  input                multi-dimensional input
     */
    template<class T>
    JMultiPDF(const T& input) 
    {
      insert(input);

      this->compile();
    }

    
    /**
     * Insert multi-dimensional input.
     *
     * \param  input                multi-dimensional histogram
     */
    template<class JHistogram_t, class JHistogramMaplist_t, class JHistogramDistance_t>
    void insert(const JMultiHistogram<JHistogram_t, JHistogramMaplist_t, JHistogramDistance_t>& input)
    {
      this->insert(JMultiKey<0, argument_type>(), input, input.getIntegral());
    }

    
    /**
     * Insert multi-dimensional input.
     *
     * \param  input                multi-dimensional histogram
     */
    template<class JHistogram_t, class JHistogramMaplist_t, class JHistogramDistance_t>
    void insert(const JTransformableMultiHistogram<JHistogram_t, JHistogramMaplist_t, JHistogramDistance_t>& input)
    {
      this->transformer.reset(input.transformer->clone());

      this->insert(JMultiKey<0, argument_type>(), input, input.getIntegral());
    }

  protected:
    /**
     * Recursive method to insert multi-dimensional histogram at multi-dimensional key.
     *
     * \param  key                  multi-dimensional key
     * \param  input                multi-dimensional histogram
     * \param  weight               weight
     */
    template<unsigned int N,
	     class __JAbscissa_t,
	     class __JContents_t,
	     template<class, class, class> class __JMap_t,
	     class __JDistance_t>
    void insert(const JMultiKey<N, argument_type>&                                          key, 
		const JHistogramMap<__JAbscissa_t, __JContents_t, __JMap_t, __JDistance_t>& input,
		const double                                                                weight)
    {
      if (input.size() > 1) {

	for (typename JHistogramMap<__JAbscissa_t, __JContents_t, __JMap_t, __JDistance_t>::const_iterator j = input.begin(), i = j++; j != input.end(); ++i, ++j) {
	  
	  const argument_type x = 0.5 * (i->getX() + j->getX());
	  const double        w = weight * input.getDistance(i->getX(), j->getX());

	  insert(JMultiKey<N+1, argument_type>(key, x), i->getY(), w);
	}
      }
    }


    /**
     * Termination method to insert multi-dimensional histogram at multi-dimensional key.
     *
     * Convert one-dimensional histogram to PDF, normalise PDF with given weight and insert result at given multi-dimensional key.
     *
     * \param  key                  multi-dimensional key
     * \param  input                histogram
     * \param  weight               weight
     */
    template<class __JElement_t, 
	     template<class, class> class __JContainer_t,
	     class __JDistance_t>
    void insert(const JMultiKey<JMapLength<JMaplist_t>::value, argument_type>&   key, 
		const JHistogram1D<__JElement_t, __JContainer_t, __JDistance_t>& input, 
		const double                                                     weight)
    {
      JFunction_t buffer;
      
      makePDF(input, buffer);
      
      buffer.div(weight);

      transformablemultifunction_type::insert(key, buffer);
    }    
  };
  

  /**
   * Conversion of multi-dimensional histogram to multi-dimensional PDF.
   *
   * \param  input             multi-dimensional histogram
   * \param  output            multi-dimensional PDF
   */
  template<class JHistogram_t,
	   class JHistogramMaplist_t,
	   class JHistogramDistance_t,
	   class JFunction_t,
	   class JFunctionMaplist_t,
	   class JFunctionDistance_t>
  inline void makePDF(const JMultiHistogram<JHistogram_t, JHistogramMaplist_t, JHistogramDistance_t>& input, 
		      JMultiPDF<JFunction_t, JFunctionMaplist_t, JFunctionDistance_t>&                output)
  {
    output.insert(input);
  }
}

#endif