//-----------------------------------------------------------
// File and Version Information:
// $Id$
//
// Description:
//      Implementation of class TpcClusterizerTask
//      see TpcClusterizerTask.hh for details
//
// Environment:
//      Software developed for the PANDA Detector at FAIR.
//
// Author List:
//      Sebastian Neubert    TUM            (original author)
//
//
//-----------------------------------------------------------

// Panda Headers ----------------------

// This Class' Header ------------------
#include "TpcClusterizerTask.h"

// C/C++ Headers ----------------------


// Collaborating Class Headers --------
#include "CbmRootManager.h"
#include "TClonesArray.h"
#include "TpcPoint.h"
#include "TpcGas.h"
#include "TRandom.h"
#include "TpcPrimaryCluster.h"
#include "LinearInterpolPolicy.h"

// Class Member definitions -----------


TpcClusterizerTask::TpcClusterizerTask()
  : CbmTask("TPC Clusterizer"), _persistence(kFALSE)
{
  _pointBranchName = "TpcPoint";
  _gas= new TpcGas("NEON-90_CO2-10_B2_PRES1013.asc",400);
  std::cout<<*_gas<<std::endl;
}


TpcClusterizerTask::~TpcClusterizerTask()
{}

InitStatus
TpcClusterizerTask::Init()
{
  //Get ROOT Manager
  CbmRootManager* ioman= CbmRootManager::Instance();

  if(ioman==0)
    {
      Error("TpcClusterizerTask::Init","RootManager not instantiated!");
      return kERROR;
    }
  
  // Get input collection
  _pointArray=(TClonesArray*) ioman->GetObject(_pointBranchName);
  
  if(_pointArray==0)
    {
      Error("TpcClusterizerTask::Init","Point-array not found!");
      return kERROR;
    }
  
  // create and register output array
  _primArray = new TClonesArray("TpcPrimaryCluster"); 
  ioman->Register("TpcPrimaryCluster","Tpc",_primArray,_persistence);

  return kSUCCESS;
}


void
TpcClusterizerTask::Exec(Option_t* opt)
{
  // Reset output Array
  if(_primArray==0) Fatal("TpcPrimCluster::Exec)","No PrimClusterArray");
  _primArray->Delete();

  TpcPoint* point;
  TpcPoint* theLastPoint;
  Int_t icluster=0;
  

  Int_t np=_pointArray->GetEntriesFast();
  if(np<2){
    Warning("TpcClusterizerTask::Exec","Not enough Hits in Tpc for Digitization (<2)");
    return;
  }

  theLastPoint= (TpcPoint*)_pointArray->At(0);

  for(int ip=1;ip<np;++ip){
    point=(TpcPoint*) _pointArray->At(ip);
    //point->Print();

    //check if hits ly on the same track
    if(point->GetTrackID()==theLastPoint->GetTrackID()){
      double dE=point->GetEnergyLoss()*1E9; //convert from GeV to eV

      //Step 0: calculate the overall ammount of charge, produced
      if(dE<0){
        Error("TpcClusterizerTask::Exec","Note: particle:: negative Energy loss!");
        continue;
      }
      unsigned int q_total =(unsigned int)floor(fabs(dE / _gas->W()));
      unsigned int q_cluster=0;
      unsigned int ncluster=0;
      //Step 1: Create Clusters

      //while still charge not used-up distribute charge into next cluster

      while(q_total>0){
        //roll dice for next clustersize
        q_cluster=_gas->GetRandomCS(gRandom->Uniform());
        if(q_cluster>q_total)q_cluster=q_total;
        q_total-=q_cluster;
        // create cluster
	Int_t size = _primArray->GetEntriesFast();
	new((*_primArray)[size]) TpcPrimaryCluster(point->GetTime(),
						   q_cluster,
						   TVector3(0,0,0),
						   point->GetTrackID(),
						   ip);
	
        ++ncluster;
     }// finish loop for cluster creation

      //Step 2: Distribute Clusters along track segment
      LinearInterpolPolicy().Interpolate(theLastPoint,point,_primArray,icluster,ncluster);
      icluster+=ncluster;
      }//end check for same track
    theLastPoint=point;
  } // finish loop over GHits

  std::cout<<"TpcClusterizer:: "<<_primArray->GetEntriesFast()<<" clusters created"<<std::endl;

  return;
}

ClassImp(TpcClusterizerTask)