// -------------------------------------------------------------------------
// -----                   CbmPVFinderIdeal source file                -----
// -----                  Created 28/11/05  by V. Friese               -----
// -------------------------------------------------------------------------
#include "CbmPVFinderIdeal.h"

#include "CbmVertex.h"

#include "CbmMCTrack.h"
#include "FairRootManager.h"

#include "TClonesArray.h"

#include <iostream>

using std::cout;
using std::endl;



// -----   Default constructor   -------------------------------------------
CbmPVFinderIdeal::CbmPVFinderIdeal() 
  : CbmPrimaryVertexFinder(),
    fMCTracks(NULL)
{
}
// -------------------------------------------------------------------------



// -----   Destructor   ----------------------------------------------------
CbmPVFinderIdeal::~CbmPVFinderIdeal() { }
// -------------------------------------------------------------------------



// -----   Public method Init   --------------------------------------------
void CbmPVFinderIdeal::Init() {

  // Get and check FairRootManager
  FairRootManager* ioman = FairRootManager::Instance();
  if (! ioman) {
    cout << "-E- CbmPVFinderIdeal::Init: "
	 << "RootManager not instantised!" << endl;
    return;
  }

  // Get MCTrack array
  fMCTracks  = (TClonesArray*) ioman->GetObject("MCTrack");
  if ( ! fMCTracks) {
    cout << "-E- CbmPVFinderIdeal::Init: No MCTrack array!"
	 << endl;
    return;
  }

}
// -------------------------------------------------------------------------



// -----   Public method FindPrimaryVertex   -------------------------------
Int_t CbmPVFinderIdeal::FindPrimaryVertex(TClonesArray* tracks,
					  CbmVertex* vertex) {

  if ( ! fMCTracks ) return 1;

  CbmMCTrack* mcTrack  = NULL;
  CbmMCTrack* refTrack = NULL;
  Int_t nPrim = 0;
  Int_t nTracks = fMCTracks->GetEntriesFast();

  for (Int_t iTrack=0; iTrack<nTracks; iTrack++) {
    mcTrack = (CbmMCTrack*) fMCTracks->At(iTrack);
    if ( ! mcTrack ) continue;
    if ( mcTrack->GetMotherId() != -1 ) continue;  // secondary
    nPrim++;
    refTrack = mcTrack;
  }

  Double_t x    = 0.;
  Double_t y    = 0.;
  Double_t z    = 0;
  Double_t chi2 = 0.;
  Int_t ndf     = 0;
  TMatrixFSym covMat(3);
  if (refTrack) {
    x = refTrack->GetStartX();
    y = refTrack->GetStartY();
    z = refTrack->GetStartZ();
  }
  else cout << "-W- CbmPVFinderIdeal::FindPrimaryVertex: "
	    << "No primary MCTracks found!" << endl;


  vertex->SetVertex(x, y, z, chi2, ndf, nPrim, covMat);
 
  return 0;
}
// -------------------------------------------------------------------------



ClassImp(CbmPVFinderIdeal)