#ifndef __JAANET__JDIFFUSEFLUXHELPER__
#define __JAANET__JDIFFUSEFLUXHELPER__

#include "km3net-dataformat/offline/Evt.hh"

#include "JAAnet/JEvtWeightFactor.hh"
#include "JAAnet/JDiffuseFlux.hh"
#include "JAAnet/JEvtWeightFactorHelper.hh"
#include "JAAnet/JFluxHelper.hh"


/**
 * \author bjung
 */

namespace JAANET {}
namespace JPP { using namespace JAANET; }

namespace JAANET {

  /**
   * Helper class for diffuse flux factor.
   */
  struct JDiffuseFluxHelper :
    public JFluxHelper
  {
    typedef typename JFluxHelper::pointer_type     pointer_type;
    
    
    /**
     * Default constructor.
     */
    JDiffuseFluxHelper()
    {}
    
    
    /**
     * Constructor.
     *
     * \param  flux              diffuse flux
     */
    JDiffuseFluxHelper(const pointer_type& flux) :
      JFluxHelper(flux)
    {}
    
    
    /**
     * Constructor.
     *
     * \param  flux              diffuse flux
     */
    JDiffuseFluxHelper(const JDiffuseFlux& flux)
    {
      configure(flux);
    }


    /**
     * Get reference to diffuse flux function.
     *
     * \return                   reference to diffuse flux function.
     */
    JDiffuseFlux& getDiffuseFlux() const
    {
      using namespace JPP;

      JEvtWeightFactor& factor = JEvtWeightFactorHelper::getFactor();

      JDiffuseFlux* p = dynamic_cast<JDiffuseFlux*>(&factor);

      if (p != NULL) {
	return *p;
      } else {
	THROW(JNullPointerException, "JDiffuseFluxHelper::getDiffuseFlux(): Cannot convert event-weight factor to diffuse flux function.");
      }
   }


    /**
     * Get flux for given particle PDG-identifier, energy and zenith-angle.
     *
     * \param  type              PDG particle type
     * \param  log10E            logarithmic neutrino energy [GeV]
     * \param  costh             cosine zenith angle
     * \return                   diffuse flux [GeV^-1 * m^-2 * sr^-1 * s^-1]
     */
    double getFactor(const int    type,
		     const double log10E,
		     const double costh) const
    {
      const JDiffuseFlux& flux = getDiffuseFlux();
      
      return flux(type, log10E, costh);
    }
    

    /**
     * Get flux for given particle PDG-identifier, energy and zenith-angle.
     *
     * \param  type              PDG particle type
     * \param  log10E            logarithmic neutrino energy [GeV]
     * \param  costh             cosine zenith angle
     * \return                   diffuse flux [GeV^-1 * m^-2 * sr^-1 * s^-1]
     */
    double getFlux(const int    type,
		   const double log10E,
		   const double costh) const
    {
      return getFactor(type, log10E, costh);
    }


    /**
     * Get flux for given particle PDG-identifier, energy and zenith-angle.
     *
     * \param  type              PDG particle type
     * \param  log10E            logarithmic neutrino energy [GeV]
     * \param  costh             cosine zenith angle
     * \return                   diffuse flux [GeV^-1 * m^-2 * sr^-1 * s^-1]
     */
    double operator()(const int    type,
		      const double log10E,
		      const double costh) const
    {
      return getFactor(type, log10E, costh);
    }
  };
}

#endif