// $Id$

//_______________________________________________________________________
/////////////////////////////////////////////////////////////////////////
//
// class AliJetParticlesReaderKine
//
// Reader for Kinematics
//
// loizides@ikf.uni-frankfurt.de
//
/////////////////////////////////////////////////////////////////////////

#include <Riostream.h>
#include <TString.h>
#include <TParticle.h>
#include <AliRunLoader.h>
#include <AliStack.h>

#include "AliJetParticle.h"
#include "AliJetEventParticles.h"
#include "AliJetParticlesReaderKine.h"

ClassImp(AliJetParticlesReaderKine)


/**********************************************************/

AliJetParticlesReaderKine::AliJetParticlesReaderKine() :
  AliJetParticlesReader(),
  fFileName("galice.root"),
  fRunLoader(0),
  fNeutral(kTRUE),fCharged(kTRUE),fEM(kTRUE),
  fUseTracks(kFALSE)
{
  //constructor
}

/**********************************************************/


AliJetParticlesReaderKine::AliJetParticlesReaderKine(TString& fname) :
  AliJetParticlesReader(),
  fFileName(fname),
  fRunLoader(0),
  fNeutral(kTRUE),fCharged(kTRUE),fEM(kTRUE),
  fUseTracks(kFALSE)
{
  //constructor
}

/**********************************************************/

AliJetParticlesReaderKine::AliJetParticlesReaderKine(TObjArray* dirs, const Char_t *filename):
  AliJetParticlesReader(dirs),
  fFileName(filename),
  fRunLoader(0),
  fNeutral(kTRUE),fCharged(kTRUE),fEM(kTRUE),
  fUseTracks(kFALSE)
{
  //constructor
}

/**********************************************************/

AliJetParticlesReaderKine::~AliJetParticlesReaderKine()
{
  //destructor
  if(fRunLoader) delete fRunLoader;
}

/**********************************************************/

void AliJetParticlesReaderKine::Rewind()
{
  //Rewinds to the beginning
  if(fRunLoader) delete fRunLoader;
  fRunLoader = 0;
  fCurrentDir = 0;
  fNEventsRead= 0;  
}

/**********************************************************/

Int_t AliJetParticlesReaderKine::ReadNext()
{
  //Reads Kinematics Tree

  if((!fOwner) || (fEventParticles == 0)) 
    fEventParticles = new AliJetEventParticles();

  while(fCurrentDir < GetNumberOfDirs())
    { 
      if (!OpenFile(fCurrentDir))
      { 
	fCurrentDir++;
	continue;
      }
    
      if (fCurrentEvent == fRunLoader->GetNumberOfEvents())
	{
	  //read next directory
	  delete fRunLoader; //close current session
	  fRunLoader = 0;    //assure pointer is null
	  fCurrentDir++;     //go to next dir
	  continue; 
	}
     
      //Info("ReadNext","Reading Event %d",fCurrentEvent);

      fRunLoader->GetEvent(fCurrentEvent);
      AliStack* stack = fRunLoader->Stack();
      if (!stack)
	{
	  Error("ReadNext","Can not get stack for event %d",fCurrentEvent);
	  continue;
	}

      //get vertex
      const TParticle *kv = stack->Particle(0);
      if(kv) {
	fEventParticles->SetVertex(kv->Vx(),kv->Vy(),kv->Vz());
      }

      Int_t npart = stack->GetNprimary();
      if(fUseTracks)
	npart = stack->GetNtrack();

      fEventParticles->Reset(npart);
      for (Int_t i = 0;i<npart; i++)
	{
	  TParticle *p = stack->Particle(i);
	  if(!p) continue;
	  Int_t child1 = p->GetFirstDaughter();
	  //Int_t child2 = p->GetLastDaughter();	
	  //Int_t mother = p->GetFirstMother();	   
	  if((child1>=0) && (child1<npart)) continue; 
	  //cout << child1 << " " << child2 << " " << mother << endl;

	  if(IsAcceptedParticle(p)) //put particle in event
	    fEventParticles->AddParticle(p,i); 
	}
      fCurrentEvent++;
      fCurrentDir++;
      fNEventsRead++;
      return kTRUE;
    }
      //end of loop over directories specified in fDirs Obj Array
  return kFALSE;
}

/**********************************************************/

Int_t AliJetParticlesReaderKine::OpenFile(Int_t n)
{
  //opens file with kine tree

  const TString& dirname = GetDirName(n);
  if (dirname == "")
    { 
      Error("OpenNextFile","Can not get directory name with index %d",n);
      return kFALSE;
    }

  TString filename = dirname +"/"+ fFileName;
  if(fRunLoader) delete fRunLoader;
  fRunLoader = AliRunLoader::Open(filename.Data()); 

  if (fRunLoader == 0)
    {
      Error("OpenNextFile","Can't open session from file %s",filename.Data());
      return kFALSE;
    }
  
  if (fRunLoader->GetNumberOfEvents() <= 0)
    {
      Error("OpenNextFile","There is no events in this directory.");
      delete fRunLoader;
      fRunLoader = 0;
      return kFALSE;
    }
  
  if (fRunLoader->LoadKinematics())
    {
      Error("OpenNextFile","Error occured while loading kinematics.");
      return kFALSE;
    }
  
  fCurrentEvent = 0;
  return kTRUE;
}