// @(#) $Id: AliHLTTPCCATrackletSelector.cxx 27042 2008-07-02 12:06:02Z richterm $
// **************************************************************************
// This file is property of and copyright by the ALICE HLT Project          *
// ALICE Experiment at CERN, All rights reserved.                           *
//                                                                          *
// Primary Authors: Sergey Gorbunov <sergey.gorbunov@kip.uni-heidelberg.de> *
//                  Ivan Kisel <kisel@kip.uni-heidelberg.de>                *
//                  for The ALICE HLT Project.                              *
//                                                                          *
// Permission to use, copy, modify and distribute this software and its     *
// documentation strictly for non-commercial purposes is hereby granted     *
// without fee, provided that the above copyright notice appears in all     *
// copies and that both the copyright notice and this permission notice     *
// appear in the supporting documentation. The authors make no claims       *
// about the suitability of this software for any purpose. It is            *
// provided "as is" without express or implied warranty.                    *
//                                                                          *
//***************************************************************************


#include "AliHLTTPCCATrackletSelector.h"
#include "AliHLTTPCCATrack.h"
#include "AliHLTTPCCATracker.h"
#include "AliHLTTPCCATrackParam.h"
#include "AliHLTTPCCATracklet.h"
#include "AliHLTTPCCAMath.h"

GPUd() void AliHLTTPCCATrackletSelector::Thread
( int nBlocks, int nThreads, int iBlock, int iThread, int iSync,
  AliHLTTPCCASharedMemory &s, AliHLTTPCCATracker &tracker )
{
  // select best tracklets and kill clones

  if ( iSync == 0 ) {
    if ( iThread == 0 ) {
      if ( iBlock == 0 ) {
        CAMath::AtomicExch( tracker.NTracks(), 0 );
        CAMath::AtomicExch( tracker.NTrackHits(), 0 );
      }
      s.fNTracklets = *tracker.NTracklets();
      s.fNThreadsTotal = nThreads * nBlocks;
      s.fItr0 = nThreads * iBlock;
    }
  } else if ( iSync == 1 ) {
    AliHLTTPCCATrack tout;
    int trackHits[160];

    for ( int itr = s.fItr0 + iThread; itr < s.fNTracklets; itr += s.fNThreadsTotal ) {

      AliHLTTPCCATracklet &tracklet = tracker.Tracklets()[itr];

      int tNHits = tracklet.NHits();
      if ( tNHits <= 0 ) continue;

      const int kMaxRowGap = 4;
      const float kMaxShared = .1;

      int firstRow = tracklet.FirstRow();
      int lastRow = tracklet.LastRow();

      tout.SetNHits( 0 );
      int kind = 0;
      if ( 0 ) {
        if ( tNHits >= 10 && 1. / .5 >= CAMath::Abs( tracklet.Param().QPt() ) ) { //SG!!!
          kind = 1;
        }
      }

      int w = ( kind << 29 ) + ( tNHits << 16 ) + itr;

      //int w = (tNHits<<16)+itr;
      //int nRows = tracker.Param().NRows();
      int gap = 0;
      int nShared = 0;
      //std::cout<<" store tracklet: "<<firstRow<<" "<<lastRow<<std::endl;
      for ( int irow = firstRow; irow <= lastRow; irow++ ) {
        gap++;
        int ih = tracklet.RowHit( irow );
        if ( ih >= 0 ) {
          int ihTot = tracker.Row( irow ).FirstHit() + ih;
          bool own = ( tracker.HitWeights()[ihTot] <= w );
          bool sharedOK = ( ( tout.NHits() < 0 ) || ( nShared < tout.NHits() * kMaxShared ) );
          if ( own || sharedOK ) {//SG!!!
            gap = 0;
            int th = AliHLTTPCCATracker::IRowIHit2ID( irow, ih );
            trackHits[tout.NHits()] = th;
            tout.SetNHits( tout.NHits() + 1 );
            if ( !own ) nShared++;
          }
        }

        if ( gap > kMaxRowGap || irow == lastRow ) { // store
          if ( tout.NHits() >= 10 ) { //SG!!!
            int itrout = CAMath::AtomicAdd( tracker.NTracks(), 1 );
            tout.SetFirstHitID( CAMath::AtomicAdd( tracker.NTrackHits(), tout.NHits() ) );
            tout.SetParam( tracklet.Param() );
            tout.SetAlive( 1 );
            tracker.Tracks()[itrout] = tout;
            for ( int jh = 0; jh < tout.NHits(); jh++ ) {
              tracker.TrackHits()[tout.FirstHitID() + jh] = trackHits[jh];
            }
          }
          tout.SetNHits( 0 );
          gap = 0;
          nShared = 0;
        }
      }
    }
  }
}