#ifndef __JAANET__JEVTWEIGHTGSEAGEN__
#define __JAANET__JEVTWEIGHTGSEAGEN__

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

#include "JLang/JException.hh"
#include "JLang/JClonable.hh"

#include "JAAnet/JHead.hh"
#include "JAAnet/JHeadToolkit.hh"
#include "JAAnet/JEvtWeight.hh"
#include "JAAnet/JEvtWeightFactorHelper.hh"
#include "JAAnet/JFlux.hh"


/**
 * \author bjung
 */

namespace JAANET {
  
  using JLANG::JClonable;
  using JLANG::JIndexOutOfRange;
  using JLANG::JNullPointerException;

  
  /**
   * Implementation of event weighting for GSeaGen data.
   */
  struct JEvtWeightGSeaGen :
    public JClonable<JEvtWeight, JEvtWeightGSeaGen>,
    public JEvtWeightFactorHelper<JFlux>
  {
    typedef JEvtWeightFactorHelper<JFlux>    JFluxHelper_t;
    
    
    /**
     * Default Constructor.
     */
    JEvtWeightGSeaGen() :
      JFluxHelper_t()
    {}


    /** 
     * Constructor.
     *
     * \param  header            header
     */    
    JEvtWeightGSeaGen(const JHead& header) :
      JFluxHelper_t()
    {
      configure(header);
    }


    /** 
     * Constructor.
     *
     * \param  header            header
     * \param  flux              flux
     */
    JEvtWeightGSeaGen(const JHead& header,
		      const JFlux& flux) :
      JFluxHelper_t()
    {
      configure(header);
      JFluxHelper_t::configure(flux);
    }
    

    /**
     * Copy constructor.
     *
     * \param  object           original object
     */
    JEvtWeightGSeaGen(const JEvtWeightGSeaGen& object)
    {
      this->norm = object.norm;
      
      if (object.is_valid()) {
	JFluxHelper_t::configure(*(object.get()));
      }
    }
    
    
    /**
     * Weight normalisation configuration.
     *
     * \param  header            header
     */
    void configure(const JHead& header) override
    {
      const double Nevents = header.genvol.numberOfEvents;
      const double dt      = (header.tgen.numberOfSeconds > 0.0 ?
			      header.tgen.numberOfSeconds : 1.0);
      
      if (check(header) && Nevents > 0.0 && dt > 0.0) {
	
        norm = 1.0 / Nevents / dt;
	
      } else {

	THROW(JValueOutOfRange, "JEvtWeightGSeaGen::configure(): Provided header is inconsistent with GSeaGen.");
      }
    }


    /**
     * Check whether header is consistent with this event weighter.
     *
     * \param  header            header
     * \return                   true if consistent; else false
     */
    bool check(const JHead& header) const override
    {
      return is_gseagen(header);
    }

    
    /**
     * Get weight of given event.
     *
     * \param  evt               event
     * \return                   weight        [Hz]
     */
    double getWeight(const Evt& evt) const override
    {
      if (is_valid() && evt.w.size() > 1) {
	
	return evt.w[1] * getFactor(evt) * norm;
	
      } else if (evt.w.size() > 2) {

	return evt.w[2] * norm;
	
      } else {

	if (!is_valid()) {
	  THROW(JNullPointerException, "JEvtWeightGSeaGen::getWeight(): Unspecified flux function.");
	} else {
	  THROW(JIndexOutOfRange,      "JEvtWeightGSeaGen::getWeight(): Empty " << (evt.w.size() < 3 ? "w2-" : "w3-") << "weight.");
	}
      }
    }
  };
}

#endif