#ifndef __JPHYSICS__JCDFTABLE__
#define __JPHYSICS__JCDFTABLE__

#include "JIO/JSerialisable.hh"
#include "JIO/JObjectBinaryIO.hh"
#include "JLang/JException.hh"
#include "JLang/JSharedPointer.hh"
#include "JMath/JZero.hh"
#include "JTools/JArray.hh"
#include "JTools/JMultiKey.hh"
#include "JTools/JTransformableMultiFunction.hh"
#include "JTools/JTransformableMultiHistogram.hh"
#include "JTools/JConstantFunction1D.hh"
#include "JTools/JToolsToolkit.hh"
#include "JTools/JTransformableMultiHistogram.hh"
#include "JTools/JHistogramMap.hh"
#include "JPhysics/JPDFTransformer.hh"


/**
 * \author mdejong
 */

namespace JPHYSICS {}
namespace JPP { using namespace JPHYSICS; }

namespace JPHYSICS {

  using JIO::JSerialisable;
  using JIO::JReader;
  using JIO::JWriter;
  using JIO::JObjectBinaryIO;
  using JLANG::JException;
  using JTOOLS::JFunctional;
  using JTOOLS::JTransformableMultiFunction;
  using JTOOLS::JTransformableMultiHistogram;
  using JTOOLS::JMultiMap;
  using JTOOLS::JMultiKey;
  using JTOOLS::JArray;
  using JTOOLS::JHistogramMap;


  /**
   * Multi-dimensional CDF table for arrival time of Cherenkov light.
   * This class can be used to determine the number of photo-electrons as a function of
   * the values of the leading parameter values and to generate random photon arrival times.
   *
   * N.B. The transformation of the PDF is assumed to be linear.
   */
  template<class JFunction1D_t,
           class JMaplist_t,
           class JDistance_t = JTOOLS::JDistance<typename JFunction1D_t::argument_type> >
  class JCDFTable :
    public JSerialisable,
    public JObjectBinaryIO< JCDFTable<JFunction1D_t, JMaplist_t, JDistance_t> >,
    public JFunctional<>
  {
  public:

    typedef typename JFunction1D_t::argument_type                                       argument_type;
    typedef typename JFunction1D_t::result_type                                         result_type;
    typedef typename JFunction1D_t::value_type                                          value_type;

    typedef JTransformableMultiFunction<JFunction1D_t, JMaplist_t, JDistance_t>         transformablemultifunction_t;

    typedef typename transformablemultifunction_t::multimap_type                        multimap_type;
    typedef typename transformablemultifunction_t::transformer_type                     transformer_type;

    enum { NUMBER_OF_DIMENSIONS = transformablemultifunction_t::NUMBER_OF_DIMENSIONS };

    typedef JMultiKey<NUMBER_OF_DIMENSIONS - 1, argument_type>                          multikey_type;

    typedef JTOOLS::JConstantFunction1D<double, argument_type>                          JConstantFunction1D_t;
    typedef JTOOLS::JMultiFunction<JConstantFunction1D_t, JMaplist_t, JDistance_t>      JMultiQuantile_t;
    typedef JTOOLS::JMultiFunction<JFunction1D_t,         JMaplist_t, JDistance_t>      JMultiFunction_t;


    /**
     * Default constructor.
     */
    JCDFTable() :
      transformer(transformer_type::getClone())
    {}


    /**
     * Constructor.
     *
     * \param  input              multi-dimensional PDF
     * \param  eps                minimal step size for CDF
     */
    template<class __JFunction_t, class __JMaplist_t, class __JDistance_t>
    JCDFTable(const JTransformableMultiFunction<__JFunction_t, __JMaplist_t, __JDistance_t>& input,
	      const typename __JFunction_t::ordinate_type                                    eps = JMATH::zero) :
      transformer(transformer_type::getClone())
    {
      this->transformer.reset(input.transformer->clone());

      for (auto i = input.super_begin(); i != input.super_end(); ++i) {
	this->insert((*i).getKey(), (*i).getValue(), eps);
      }

      this->compile();
    }

    
    /**
     * Constructor.
     *
     * \param  input              multi-dimensional histogram
     * \param  eps                minimal step size for CDF
     */
    template<class JHistogram_t, class __JMaplist_t, class __JDistance_t>    
    JCDFTable(const JTransformableMultiHistogram<JHistogram_t, __JMaplist_t, __JDistance_t>& input,
	      const typename JHistogram_t::ordinate_type                                     eps = JMATH::zero) :
      transformer(transformer_type::getClone())
    {
      this->transformer.reset(input.transformer->clone());
      
      this->insert(JMultiKey<0, typename JHistogram_t::abscissa_type>(), input, eps);
      
      this->compile();
    }


    /**
     * Application of weight function.
     *
     * \param  transformer        function transformer
     */
    template<class JFunctionTransformer_t>
    void transform(const JFunctionTransformer_t& transformer)
    {
      for (typename JMultiQuantile_t::super_iterator i = intensity.super_begin(); i != intensity.super_end(); ++i) {

	const typename transformer_type::array_type array    = (*i).getKey();
        JConstantFunction1D_t&                      function = (*i).getValue();

	const double W1 = this->transformer->getWeight(array);
	const double W2 =       transformer .getWeight(array);

	const result_type y  = function(JMATH::zero);

	function = JConstantFunction1D_t(y * W1 / W2);
      }

      this->transformer.reset(transformer.clone());
      this->compile();
    }


    /**
     * Get number of photo-electrons.
     *
     * \param  args               comma separated argument list
     * \return                    number of photo-electrons
     */
    template<class ...Args>
    double getNPE(const Args& ...args) const
    {
      const JArray<NUMBER_OF_DIMENSIONS - 1, argument_type> buffer(args...);

      const double W   = transformer->getWeight(buffer);
      const double npe = intensity.evaluate(buffer.data());

      return W * npe;
    }


    /**
     * Generate arrival time.
     *
     * \param  args               comma seperated argument list (last value is random number between 0 and 1)
     * \return                    arrival time
     */
    template<class ...Args>
    double getTime(const Args& ...args) const
    {
      const JArray<NUMBER_OF_DIMENSIONS, argument_type> buffer(args...);

      const argument_type y = function.evaluate(buffer.data());

      return transformer->getXn(buffer, y);
    }


    /**
     * Read CDF from input.
     *
     * \param  in                 reader
     * \return                    reader
     */
    virtual JReader& read(JReader& in) override
    {
      in >> intensity;
      in >> function;

      JPDFTransformer<NUMBER_OF_DIMENSIONS - 1, argument_type> buffer;

      if (buffer.read(in))
	transformer.reset(buffer.clone());
      else
	transformer.reset(transformer_type::getClone());

      compile();

      intensity.setExceptionHandler(new typename JMultiQuantile_t::function_type::JDefaultResult(JMATH::zero));
      function .setExceptionHandler(new typename JMultiFunction_t::function_type::JDefaultResult(JMATH::zero));

      return in;
    }


    /**
     * Write CDF to output.
     *
     * \param  out                writer
     * \return                    writer
     */
    virtual JWriter& write(JWriter& out) const override 
    {
      out << intensity;
      out << function;

      return transformer->write(out);
    }


    JMultiQuantile_t                intensity;     // integrated PDF
    JMultiFunction_t                function;      // normalised CDF
    JLANG::JSharedPointer<transformer_type> transformer;


  protected:
    /**
     * Function compilation.
     */
    virtual void do_compile() override 
    {
      intensity.compile();
      function .compile();
    }


    /**
     * Insert value at given multidimensional key.
     *
     * \param  key                multi-dimensional key
     * \param  value              function or histogram
     * \param  eps                minimal step size for method JTOOLS::makeCDF
     */
    template<class JValue_t>
    void insert(const multikey_type&                   key,
		const JValue_t&                        value,
		const typename JValue_t::ordinate_type eps)
    {
      using namespace JPP;

      try {

	const typename transformer_type::array_type array(key);
	
	JFunction1D_t buffer;
	
	const argument_type z = transformer->getXn(array, 1.0) - transformer->getXn(array, 0.0);
	const result_type   V = makeCDF(value, buffer, eps);
	
	intensity.insert(key, JConstantFunction1D_t(z*V));
	function .insert(key, buffer);
      }	
      catch(const JException& error) {
	intensity.insert(key, JMATH::zero);
      }
    }


    /**
     * Insert multi-dimensional histogram at multi-dimensional key.
     *
     * \param  key                multidimensional key
     * \param  value              multidimensional histogram
     * \param  eps                minimal step size for CDF
     */
    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>& value,
		const __JContents_t                                                         eps)
    {
      if (value.getSize() > 1) {

	for (auto j = value.begin(), i = j++; j != value.end(); ++i, ++j) {
	  
	  const __JAbscissa_t x = 0.5 * (i->first + j->first);
	  
	  insert(JMultiKey<N+1, __JAbscissa_t>(key, x), i->second, eps);
	} 
      }
    }
  };
}

#endif