//*-- Author : B. Spruck
//*-- Modified : 2 Now 2005
//_HADES_CLASS_DESCRIPTION 
////////////////////////////////////////////////////////////////////////
//
// HHypPPEpEmGammaAlg
//
// work in progress
//
////////////////////////////////////////////////////////////////////////

using namespace std;

#include <stdlib.h>
#include <iostream>
#include "hhypPPEpEmGammaAlg.h"
#include "hypinfodef.h"

ClassImp(HHypPPEpEmGammaAlg)

HHypPPEpEmGammaAlg::HHypPPEpEmGammaAlg(Char_t *name_i, Option_t par[])
  :HHypBaseAlgorithm(name_i,par) {
}

HHypPPEpEmGammaAlg::~HHypPPEpEmGammaAlg() {
}

Bool_t HHypPPEpEmGammaAlg::execute()
{
  if (!beam) {
    cerr << algoName << " needs beam particle! " << endl;
    return kFALSE;
  }
  // Resetting the list and start looping over the combinations
  // Loop is only done over the VALID combinations
  mylist->CombIteratorReset();
  while (mylist->CombIterator()) {
    
    // Getting the particles 
    TLorentzVector proton1 = mylist->getTLorentzVector("p", 1);
    TLorentzVector proton2 = mylist->getTLorentzVector("p", 2);
    TLorentzVector ep = mylist->getTLorentzVector("e+", 1);
    TLorentzVector em = mylist->getTLorentzVector("e-", 1);
    
    if (mylist->getIterStatus() == kTRUE) {
      
      // calculating missing mass
      TLorentzVector miss4 = (*beam) - (proton1 + proton2 + ep + em);
      TLorentzVector pp_miss = (*beam) - (proton1 + proton2);
      TLorentzVector epem_invmass = (ep + em);
      
      // NOW I HAVE TO DO THE SELECTION!!!!
      // Here I set all combinations unvalid which do not fulfill 
      // the requirement
      
      if (miss4.M2() < lower_gamma_cut) {   // [MeV]
	mylist->removeComb();
	// cout << "lower removed " << miss4.M2() << endl;
      }
      else if (miss4.M2() > upper_gamma_cut) {  // [MeV]
	mylist->removeComb();
	// cout << "upper removed " << miss4.M2() << endl;
      }
      // else cout <<  "keep " << miss4.M2() << endl;
      
      // Remove unphysical events here:
      // This wont work with missing mass==0
      //			if (pp_miss.M2() < epem_invmass.M2()){
      //				mylist->removeComb();
      //			}
    }                           //END getIterStatus() == kTRUE
  }                             //END Iterator
  if (exitIdx > -1)
    return kTRUE;
  return kFALSE;
}

Bool_t HHypPPEpEmGammaAlg::init()
{
  pParams->registerCut("PPEpEmGamma_LOWER_CUT");
  pParams->registerCut("PPEpEmGamma_UPPER_CUT");
  
  return kTRUE;
}

Bool_t HHypPPEpEmGammaAlg::reinit()
{
  //Here, we set/reset the Gamma ("Restmass") cut for this run
  //Resolution could be run-dependent!
  
  if (!pParams->getCut("PPEpEmGamma_UPPER_CUT", upper_gamma_cut)) {
    upper_gamma_cut=23000.0;
    std::cout << "HHypPPEpEmGammaAlg::init: GAMMA_UPPER_CUT not found" << std::endl;
    std::cout << "using hardcoded GAMMA_UPPER_CUT" << std::endl;
    //    return kFALSE;
  }
  
  if (!pParams->getCut("PPEpEmGamma_LOWER_CUT", lower_gamma_cut)) {
    lower_gamma_cut=-23000.0;
    std::cout << "HHypPPEpEmGammaAlg::init: GAMMA_LOWER_CUT not found" << std::endl;
    std::cout << "using hardcoded GAMMA_LOWER_CUT" << std::endl;
    //    return kFALSE;
  }
  
  std::cout << "GAMMA_LOWER_CUT is: " << lower_gamma_cut << std::endl;
  std::cout << "GAMMA_UPPER_CUT is: " << upper_gamma_cut << std::endl;
  
  return kTRUE;
}

Bool_t HHypPPEpEmGammaAlg::finalize()
{
  return kTRUE;
}