#include "SHERPA/PerturbativePhysics/Shower_Handler.H"

#include "PDF/Main/ISR_Handler.H"
#include "ATOOLS/Org/Run_Parameter.H"
#include "ATOOLS/Org/Settings.H"
#include "ATOOLS/Org/Library_Loader.H"
#include "ATOOLS/Org/Exception.H"
#include "ATOOLS/Org/Message.H"
#include "ATOOLS/Org/Scoped_Settings.H"

using namespace SHERPA;
using namespace ATOOLS;

Shower_Handler::Shower_Handler(MODEL::Model_Base *const model,
                               PDF::ISR_Handler *const isr,
                               const int isrtype):
  p_shower(NULL), p_isr(isr)
{
  Settings& s = Settings::GetMainSettings();
  m_name = s["SHOWER_GENERATOR"].Get<std::string>();
  p_shower = PDF::Shower_Getter::GetObject
    (m_name,PDF::Shower_Key(model,p_isr,isrtype));
  if (p_shower==NULL && m_name!="None" &&
      s_loader->LoadLibrary("Sherpa"+m_name)) {
    p_shower = PDF::Shower_Getter::GetObject
      (m_name,PDF::Shower_Key(model,p_isr,isrtype));
  }
  if (p_shower==NULL) msg_Info()<<METHOD<<"(): No shower selected."<<std::endl;
}


Shower_Handler::~Shower_Handler() 
{
  if (p_shower) delete p_shower;
}

void Shower_Handler::FillBlobs(ATOOLS::Blob_List * _bloblist) 
{
  if (p_shower && p_shower->ExtractPartons(_bloblist)) {
    Blob * showerblob = _bloblist->FindLast(btp::Shower);
    if (!showerblob->MomentumConserved()) {
      msg_Debugging()<<"Error in "<<METHOD<<": "
		     <<"shower violates four-momentum conservation "
		     <<showerblob->CheckMomentumConservation()<<":\n"
		     <<(*showerblob);
      Vec4D extra = showerblob->CheckMomentumConservation();
      if (showerblob->InParticle(0)->Flav()==Flavour(kf_instanton) &&
	  extra.PSpat2()<1.e-8) {
	for (size_t i=1;i<3;i++) {
	  showerblob->InParticle(i)->
	    SetMomentum(showerblob->InParticle(i)->Momentum()-extra/2.);
	}
      }
    }
    return;
  }
  THROW(fatal_error,"Internal error");
}

void Shower_Handler::FillDecayBlobs(ATOOLS::Blob_List * _bloblist) 
{
  if (p_shower && p_shower->ExtractPartons(_bloblist)) return;
  THROW(fatal_error,"Internal error");
}

void Shower_Handler::CleanUp() 
{
  if (p_shower) p_shower->CleanUp();
}

void Shower_Handler::SetRemnants(REMNANTS::Remnant_Handler* remnants)
{
  if (p_shower)
    p_shower->SetRemnants(remnants);
}