// $Id$
//
//    File: JEventProcessor_diphoton.cc
// Created: Sun Nov 23 11:01:46 EST 2014
// Creator: hdcdcops (on Linux gluon47.jlab.org 2.6.32-358.23.2.el6.x86_64 x86_64)
//

#include "JEventProcessor_diphoton.h"
using namespace jana;


// Routine used to create our JEventProcessor
#include <JANA/JApplication.h>
#include <JANA/JFactory.h>
extern "C"{
void InitPlugin(JApplication *app){
	InitJANAPlugin(app);
	app->AddProcessor(new JEventProcessor_diphoton());
}
} // "C"


//------------------
// JEventProcessor_diphoton (Constructor)
//------------------
JEventProcessor_diphoton::JEventProcessor_diphoton()
{

}

//------------------
// ~JEventProcessor_diphoton (Destructor)
//------------------
JEventProcessor_diphoton::~JEventProcessor_diphoton()
{

}

//------------------
// init
//------------------
jerror_t JEventProcessor_diphoton::init(void)
{
	// This is called once at program startup. If you are creating
	// and filling historgrams in this plugin, you should lock the
	// ROOT mutex like this:
	//
	// japp->RootWriteLock();
	//  ... fill historgrams or trees ...
	// japp->RootUnLock();
	//
	if(gDirectory->Get("InvMass") == NULL)
		hInvMass = new TH2I("InvMassVsnumTrackCand","Invariant Mass vs track cand; track candidates; diphoton inv mass",11,-0.5,10.5, 2000, 0, 1);
	if(gDirectory->Get("hInvMassVsNNeutral") == NULL)
		hInvMassVsNNeutral = new TH2I("InvMassVsnumNeutral","Invariant Mass vs N_Neutral; Number Of NeutralParticles; diphoton inv mass",11,-0.5,10.5, 2000, 0, 1);
	return NOERROR;
}

//------------------
// brun
//------------------
jerror_t JEventProcessor_diphoton::brun(JEventLoop *eventLoop, int runnumber)
{
	// This is called whenever the run number changes
	return NOERROR;
}

//------------------
// evnt
//------------------
jerror_t JEventProcessor_diphoton::evnt(JEventLoop *loop, int eventnumber)
{
	// This is called for every event. Use of common resources like writing
	// to a file or filling a histogram should be mutex protected. Using
	// loop->Get(...) to get reconstructed objects (and thereby activating the
	// reconstruction algorithm) should be done outside of any mutex lock
	// since multiple threads may call this method at the same time.
	// Here's an example:
	//
	// vector<const MyDataClass*> mydataclasses;
	// loop->Get(mydataclasses);
	//
	// japp->RootWriteLock();
	//  ... fill historgrams or trees ...
	// japp->RootUnLock();

	vector<const DNeutralParticle *> neutralParticleVector;
	vector<const DTrackCandidate *> trackCandidates;
	
	loop->Get(neutralParticleVector);
	loop->Get(trackCandidates);

	int nBCAL = 0;
	for(unsigned int i = 0 ; i < neutralParticleVector.size(); i++){
		if (neutralParticleVector[i]->dNeutralShower->dEnergy < 0.75) continue;
                if (neutralParticleVector[i]->dNeutralShower->dDetectorSystem == SYS_FCAL) nBCAL++;
	}

	for(unsigned int i = 0 ; i < neutralParticleVector.size(); i++){
		if (neutralParticleVector[i]->dNeutralShower->dDetectorSystem != SYS_FCAL) continue;
		if (neutralParticleVector[i]->dNeutralShower->dEnergy < 0.75) continue;
		const DNeutralParticleHypothesis * gamma1 = neutralParticleVector[i]->Get_Hypothesis(Gamma);
		for(unsigned int j = i+1 ; j < neutralParticleVector.size(); j++){
			if (neutralParticleVector[j]->dNeutralShower->dDetectorSystem != SYS_FCAL) continue;
			if (neutralParticleVector[j]->dNeutralShower->dEnergy < 0.75) continue;
			if (fabs((neutralParticleVector[i]->dNeutralShower->dSpacetimeVertex).T() - (neutralParticleVector[j]->dNeutralShower->dSpacetimeVertex).T()) > 5) continue;
			const DNeutralParticleHypothesis * gamma2 = neutralParticleVector[j]->Get_Hypothesis(Gamma);
			const DLorentzVector g1p4 = gamma1->lorentzMomentum();
			const DLorentzVector g2p4 = gamma2->lorentzMomentum();
			japp->RootWriteLock();
			hInvMass->Fill( trackCandidates.size(), (g1p4 + g2p4).M() );
			hInvMassVsNNeutral->Fill( nBCAL, (g1p4 + g2p4).M() );
			japp->RootUnLock();
		}
	}
	return NOERROR;
}

//------------------
// erun
//------------------
jerror_t JEventProcessor_diphoton::erun(void)
{
	// This is called whenever the run number changes, before it is
	// changed to give you a chance to clean up before processing
	// events from the next run number.
	return NOERROR;
}

//------------------
// fini
//------------------
jerror_t JEventProcessor_diphoton::fini(void)
{
	// Called before program exit after event processing is finished.
	return NOERROR;
}