// $Id$
//
//    File: DCustomAction_DeltaPhi.cc
// Created: Wed Dec 21 13:24:54 EST 2016
// Creator: jrsteven (on Linux ifarm1402.jlab.org 3.10.0-327.el7.x86_64 x86_64)
//

#include "DCustomAction_DeltaPhi.h"

void DCustomAction_DeltaPhi::Initialize(JEventLoop* locEventLoop)
{
	//Optional: Create histograms and/or modify member variables.
	//Create any histograms/trees/etc. within a ROOT lock. 
		//This is so that when running multithreaded, only one thread is writing to the ROOT file at a time. 
	//NEVER: Get anything from the JEventLoop while in a lock: May deadlock

	//CREATE THE HISTOGRAMS
	//Since we are creating histograms, the contents of gDirectory will be modified: must use JANA-wide ROOT lock
	japp->RootWriteLock(); //ACQUIRE ROOT LOCK!!
	{
		// Optional: Useful utility functions.
		locEventLoop->GetSingle(dAnalysisUtilities);

		//Required: Create a folder in the ROOT output file that will contain all of the output ROOT objects (if any) for this action.
			//If another thread has already created the folder, it just changes to it. 
		CreateAndChangeTo_ActionDirectory();
		dHist_DeltaPhi = GetOrCreate_Histogram<TH1I>("DeltaPhi", ";#Delta#phi (degrees)", 360, 0., 360.0);
	}
	japp->RootUnLock(); //RELEASE ROOT LOCK!!
}

bool DCustomAction_DeltaPhi::Perform_Action(JEventLoop* locEventLoop, const DParticleCombo* locParticleCombo)
{
	//Write custom code to perform an action on the INPUT DParticleCombo (DParticleCombo)
	//NEVER: Grab DParticleCombo or DAnalysisResults objects (of any tag!) from the JEventLoop within this function
	//NEVER: Grab objects that are created post-kinfit (e.g. DKinFitResults, etc.) from the JEventLoop if Get_UseKinFitResultsFlag() == false: CAN CAUSE INFINITE DEPENDENCY LOOP
	//NEVER: Get anything from the JEventLoop while in a lock: May deadlock

	auto locParticles = locParticleCombo->Get_FinalParticles_Measured(Get_Reaction(), d_AllCharges);

	double locDeltaPhi = (locParticles[0]->lorentzMomentum().Phi() - locParticles[1]->lorentzMomentum().Phi())*180./TMath::Pi();
	if(locDeltaPhi > 360.) locDeltaPhi -= 360.;
	if(locDeltaPhi < 0.) locDeltaPhi += 360.;

	//Optional: FILL HISTOGRAMS
	//Since we are filling histograms local to this action, it will not interfere with other ROOT operations: can use action-wide ROOT lock
	//Note, the mutex is unique to this DReaction + action_string combo: actions of same class with different hists will have a different mutex
	Lock_Action(); //ACQUIRE ROOT LOCK!!
	{
		// Fill any histograms here
		dHist_DeltaPhi->Fill(locDeltaPhi);
	}
	Unlock_Action(); //RELEASE ROOT LOCK!!

	// Cut on deltaPhi angle
	if(fabs(locDeltaPhi - 180.) > dDeltaPhiCut)
		return false;

	// Cut on extra showers
	vector<const DNeutralShower*> locUnusedNeutralShowers;
	dAnalysisUtilities->Get_UnusedNeutralShowers(locEventLoop, locParticleCombo, locUnusedNeutralShowers);

	if(locUnusedNeutralShowers.size() > 2)
		return false;

	// Remove low angle protons since these are too high in -t
	if(locParticles[1]->lorentzMomentum().Theta()*180./TMath::Pi() < 20.)
		return false;

	return true; //return false if you want to use this action to apply a cut (and it fails the cut!)
}