#ifndef __JAANET__JEVTWEIGHTFACTORHELPER__
#define __JAANET__JEVTWEIGHTFACTORHELPER__

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

#include "JLang/JSharedPointer.hh"

#include "JAAnet/JEvtWeightFactor.hh"
#include "JAAnet/JFlux.hh"
#include "JAAnet/JDiffuseFlux.hh"


/**
 * \author bjung
 */

namespace JAANET {
  
  using JLANG::JSharedPointer;
  using JLANG::JNullPointerException;
  
  
  /**
   * Helper class for event-weight factor.
   *
   * The template argument corresponds to the desired event-weight factor class.
   * This class must contain the method `getFactor(const Evt&)`.
   */
  template<class JEvtWeightFactor_t>
  struct JEvtWeightFactorHelper :
    public JSharedPointer<JEvtWeightFactor_t>
  {
    using JSharedPointer<JEvtWeightFactor_t>::is_valid;
    using JSharedPointer<JEvtWeightFactor_t>::reset;
    using JSharedPointer<JEvtWeightFactor_t>::get;    

    
    /**
     * Default constructor.
     */
    JEvtWeightFactorHelper()
    {}
    
    
    /**
     * Constructor.
     *
     * \param  factor            event-weight factor
     */
    JEvtWeightFactorHelper(const JEvtWeightFactor_t& factor)
    {
      configure(factor);
    }
    
    
    /**
     * Configure event-weight factor.
     *
     * \param  factor            event-weight factor
     */
    void configure(const JEvtWeightFactor_t& factor)
    {
      JEvtWeightFactor_t* p = dynamic_cast<JEvtWeightFactor_t*>(factor.clone());

      if (p != NULL) {
	reset(p);
      } else {
	THROW(JNullPointerException, "JEvtWeightFactorHelper::configure(): Invalid downcast to class derived from JEvtWeightFactor.");
      }
    }

    
    /**
     * Get weight-factor of given event.
     *
     * \param  evt               event
     * \return                   event-weight factor
     */
    double getFactor(const Evt& evt) const
    {
      if (is_valid()) {
	return get()->getFactor(evt);
      } else {
	THROW(JNullPointerException, "JEvtWeightFactorHelper::getFactor(): Unspecified event-weighting factor.");
      }
    }
  };


  /**
   * Explicit emplate specialization of event-weight factor helper for diffuse flux objects.
   */
  template<>
  struct JEvtWeightFactorHelper<JDiffuseFlux> :
    public JSharedPointer<JDiffuseFlux>
  {
    using JSharedPointer<JDiffuseFlux>::is_valid;

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


    /**
     * Constructor.
     *
     * \param  diffuseFlux       diffuse flux function
     */
    JEvtWeightFactorHelper(const JDiffuseFlux& diffuseFlux)
    {
      configure(diffuseFlux);
    }


    /**
     * Configure oscillation probability function.
     *
     * \param  diffuseFlux       diffuse flux function
     */    
    void configure(const JDiffuseFlux& diffuseFlux)
    {
      JDiffuseFlux* p = dynamic_cast<JDiffuseFlux*>(diffuseFlux.clone());

      if (p != NULL) {
	reset(p);
      } else {
	THROW(JNullPointerException, "JEvtWeightFactorHelper<JDiffuseFlux>::configure(): Invalid downcast from JEvtWeightFactor to JDiffuseFlux.");
      }      
    }


    /**
     * Get diffuse flux corresponding to given neutrino type, 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
    {
      if (is_valid()) {
	return get()->getFactor(type, log10E, costh);
      } else {
	THROW(JNullPointerException, "JEvtWeightFactorHelper<JDiffuseFlux>::dNdEdOmega(): Unspecified diffuse flux function.");
      }
    }


    /**
     * Get diffuse flux corresponding to given neutrino type, energy and zenith angle.
     *
     * \param  evt               event
     * \return                   diffuse flux [GeV^-1 * m^-2 * sr^-1 * s^-1]
     */
    double getFactor(const Evt& evt) const
    {
      if (is_valid()) {
	return get()->getFactor(evt);
      } else {
	THROW(JNullPointerException, "JEvtWeightFactorHelper<JDiffuseFlux>::getFactor(): Unspecified diffuse flux function.");
      }
    }
  };
  
  
  /** Type definition of event-weight factor helper for flux functions.*/
  typedef JEvtWeightFactorHelper<JFlux>          JFluxHelper;

  /** Type definition of event-weight factor helper for diffuse flux objects. */  
  typedef JEvtWeightFactorHelper<JDiffuseFlux>   JDiffuseFluxHelper;
}

#endif