#ifndef __JAANET__JEVTWEIGHTHELPER__
#define __JAANET__JEVTWEIGHTHELPER__

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

#include "JLang/JSharedPointer.hh"

#include "JAAnet/JHead.hh"
#include "JAAnet/JEvtWeight.hh"


/**
 * \author mdejong
 */

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

namespace JAANET {
  
  using JLANG::JSharedPointer;


  /**
   * Helper class for event weighing.
   */
  struct JEvtWeightHelper :
    public JSharedPointer<JEvtWeight>,
    public JHead
  {
    using JSharedPointer<JEvtWeight>::is_valid;
    
    /**
     * Default constructor.
     */
    JEvtWeightHelper() :
      counter(0)
    {}


    /**
     * Constructor.
     *
     * \param  weighter          event weighter
     */
    JEvtWeightHelper(const JEvtWeight& weighter) :
      counter(0)
    {
      this->configure(weighter);
    }
    
    
    /**
     * Configuration.
     *
     * \param  weighter          event weighter
     */
    void configure(const JEvtWeight& weighter)
    {
      counter = 0;
      
      reset(weighter.clone());
    }


    /**
     * Check if a given header is consistent with this event weighter.
     * 
     * \param  header             header
     * \return                    true if header is consistent with this event weighter; else false.              
     */
    bool check(const JHead& header) const
    {
      return (is_valid() ? get()->check(header) : false);
    }
    
    
    /**
     * Add header.
     *
     * \param  header             header
     */
    void add(const JHead& header)
    {
      using namespace JPP;
      
      if (check(header)) {
	
	if (counter == 0) {
	  JHead::setHeader(header);
	} else {
	  JHead::add(header);
	}

	++counter;
	
	get()->configure(getHeader());
	
      } else {
	
	THROW(JNullPointerException, "JEvtWeightHelper::add(): headers do not match.");
      }
    }
    
    
    /**
     * Get weight of given event.
     *
     * \param  evt               event
     * \return                   weight [Hz]
     */
    double getWeight(const Evt& evt) const
    {
      using namespace JPP;
      
      if (is_valid()) {
	return get()->getWeight(evt);
      } else {
	THROW(JNullPointerException, "JEvtWeightHelper::getWeight(): Event weighter is null.");
      }
    }


    /**
     * Get event-weight normalisation.
     *
     * \return                   event-weight normalisation
     */
    double getNormalisation() const
    {
      using namespace JPP;
      
      if (is_valid()) {
	return get()->getNormalisation();
      } else {
	THROW(JNullPointerException, "JEvtWeightHelper::getWeightNormalisation(): Event weighter is null.");
      }
    }


    /**
     * Get event-weight normalisation.
     *
     * \param  evt               event
     * \return                   event-weight normalisation
     */
    double getNormalisation(const Evt& evt) const
    {
      using namespace JPP;
      
      if (is_valid()) {
	return get()->getNormalisation(evt);
      } else {
	THROW(JNullPointerException, "JEvtWeightHelper::getWeightNormalisation(): Event weighter is null.");
      }
    }
    
    
  private:
    int counter;
  };
}

#endif