/**************************************************************************
 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * 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.                  *
 **************************************************************************/

/* $Id$ */

///////////////////////////////////////////////////////////////////////////////
//                                                                           //
//  fast TPC cluster simulation                                              //
//                                                                          //
///////////////////////////////////////////////////////////////////////////////

#include <TParticle.h>

#include "AliRunLoader.h"
#include "AliRun.h"
#include "AliMC.h"
#include "AliTPC.h"
#include "AliTPCParam.h"
#include "AliTPCClustersArray.h"
#include "AliTPCClustersRow.h"
#include "AliTPCcluster.h"
#include "AliComplexCluster.h"
#include "AliTPCFast.h"
#include "AliLog.h"

ClassImp(AliTPCFast)


//_____________________________________________________________________________
void AliTPCFast::Hits2Clusters(AliRunLoader* runLoader) const
{
  //--------------------------------------------------------
  // TPC simple cluster generator from hits
  // obtained from the TPC Fast Simulator
  // The point errors are taken from the parametrization
  //--------------------------------------------------------

  //-----------------------------------------------------------------
  // Origin: Marek Kowalski  IFJ, Krakow, Marek.Kowalski@ifj.edu.pl
  //-----------------------------------------------------------------
  // Adopted to Marian's cluster data structure by I.Belikov, CERN,
  // Jouri.Belikov@cern.ch
  //----------------------------------------------------------------
  
  /////////////////////////////////////////////////////////////////////////////
  //
  //---------------------------------------------------------------------
  //   ALICE TPC Cluster Parameters
  //--------------------------------------------------------------------
       
  

  // Cluster width in rphi
  const Float_t kACrphi=0.18322;
  const Float_t kBCrphi=0.59551e-3;
  const Float_t kCCrphi=0.60952e-1;
  // Cluster width in z
  const Float_t kACz=0.19081;
  const Float_t kBCz=0.55938e-3;
  const Float_t kCCz=0.30428;


  AliLoader* loader = runLoader->GetLoader("TPCLoader");
  if (!loader) {
    AliError("No TPC loader found");
    return;
  }
  if (!runLoader->GetAliRun()) runLoader->LoadgAlice();
  AliRun* aliRun = runLoader->GetAliRun();
  if (!aliRun) {
    AliError("Couldn't get AliRun object");
    return;
  }
  AliTPC* tpc = (AliTPC*) aliRun->GetDetector("TPC");
  if (!tpc) {
    AliError("Couldn't get TPC detector");
    return;
  }
  AliTPCParam* param = tpc->GetParam();
  if (!param) {
    AliError("No TPC parameters available");
    return;
  }

  //if(fDefaults == 0) SetDefaults();

  Float_t sigmaRphi,sigmaZ,clRphi,clZ;
  //
  TParticle *particle; // pointer to a given particle
  AliTPChit *tpcHit; // pointer to a sigle TPC hit
  Int_t sector;
  Int_t ipart;
  Float_t xyz[5];
  Float_t pl,pt,tanth,rpad,ratio;
  Float_t cph,sph;
  
  //---------------------------------------------------------------
  //  Get the access to the tracks 
  //---------------------------------------------------------------
  
  TTree *tH = loader->TreeH();
  if (tH == 0x0)
    AliFatal("Can not find TreeH in folder");

  tpc->SetTreeAddress();
  
  Stat_t ntracks = tH->GetEntries();

  //Switch to the output file
  
  if (loader->TreeR() == 0x0) loader->MakeTree("R");
  
  AliDebug(1,Form("param->GetTitle() = %s",param->GetTitle()));
  
  runLoader->CdGAFile();
  //param->Write(param->GetTitle());

  AliTPCClustersArray carray;
  carray.Setup(param);
  carray.SetClusterType("AliTPCcluster");
  carray.MakeTree(loader->TreeR());

  Int_t nclusters=0; //cluster counter
  
  //------------------------------------------------------------
  // Loop over all sectors (72 sectors for 20 deg
  // segmentation for both lower and upper sectors)
  // Sectors 0-35 are lower sectors, 0-17 z>0, 17-35 z<0
  // Sectors 36-71 are upper sectors, 36-53 z>0, 54-71 z<0
  //
  // First cluster for sector 0 starts at "0"
  //------------------------------------------------------------
   
  for(Int_t isec=0;isec<param->GetNSector();isec++){
    //MI change
    param->AdjustCosSin(isec,cph,sph);
    
    //------------------------------------------------------------
    // Loop over tracks
    //------------------------------------------------------------
    
    for(Int_t track=0;track<ntracks;track++){
      tpc->ResetHits();
      tH->GetEvent(track);
      //
      //  Get number of the TPC hits
      //     
       tpcHit = (AliTPChit*)tpc->FirstHit(-1);

      // Loop over hits
      //
       while(tpcHit){
 
	 if (tpcHit->fQ == 0.) {
           tpcHit = (AliTPChit*) tpc->NextHit();
           continue; //information about track (I.Belikov)
	 }
	sector=tpcHit->fSector; // sector number

       if(sector != isec){
	 tpcHit = (AliTPChit*) tpc->NextHit();
	 continue; 
       }
	ipart=tpcHit->Track();
	particle=aliRun->GetMCApp()->Particle(ipart);
	pl=particle->Pz();
	pt=particle->Pt();
	if(pt < 1.e-9) pt=1.e-9;
	tanth=pl/pt;
	tanth = TMath::Abs(tanth);
	rpad=TMath::Sqrt(tpcHit->X()*tpcHit->X() + tpcHit->Y()*tpcHit->Y());
	ratio=0.001*rpad/pt; // pt must be in MeV/c - historical reason

	//   space-point resolutions
	
	sigmaRphi=AliTPCcluster::SigmaY2(rpad,tanth,pt);
	sigmaZ   =AliTPCcluster::SigmaZ2(rpad,tanth   );
	
	//   cluster widths
	
	clRphi=kACrphi-kBCrphi*rpad*tanth+kCCrphi*ratio*ratio;
	clZ=kACz-kBCz*rpad*tanth+kCCz*tanth*tanth;
	
	// temporary protection
	
	if(sigmaRphi < 0.) sigmaRphi=0.4e-3;
	if(sigmaZ < 0.) sigmaZ=0.4e-3;
	if(clRphi < 0.) clRphi=2.5e-3;
	if(clZ < 0.) clZ=2.5e-5;
	
	//
	
	//
	// smearing --> rotate to the 1 (13) or to the 25 (49) sector,
	// then the inaccuracy in a X-Y plane is only along Y (pad row)!
	//
        Float_t xprim= tpcHit->X()*cph + tpcHit->Y()*sph;
	Float_t yprim=-tpcHit->X()*sph + tpcHit->Y()*cph;
	xyz[0]=gRandom->Gaus(yprim,TMath::Sqrt(sigmaRphi));   // y
          Float_t alpha=(isec < param->GetNInnerSector()) ?
	  param->GetInnerAngle() : param->GetOuterAngle();
          Float_t ymax=xprim*TMath::Tan(0.5*alpha);
          if (TMath::Abs(xyz[0])>ymax) xyz[0]=yprim; 
	xyz[1]=gRandom->Gaus(tpcHit->Z(),TMath::Sqrt(sigmaZ)); // z
          if (TMath::Abs(xyz[1])>param->GetZLength()) xyz[1]=tpcHit->Z(); 
	xyz[2]=sigmaRphi;                                     // fSigmaY2
	xyz[3]=sigmaZ;                                        // fSigmaZ2
	xyz[4]=tpcHit->fQ;                                    // q

        AliTPCClustersRow *clrow=carray.GetRow(sector,tpcHit->fPadRow);
        if (!clrow) clrow=carray.CreateRow(sector,tpcHit->fPadRow);	

        Int_t tracks[3]={tpcHit->Track(), -1, -1};
	AliTPCcluster cluster(tracks,xyz);

        clrow->InsertCluster(&cluster); nclusters++;

        tpcHit = (AliTPChit*)tpc->NextHit();
        

      } // end of loop over hits

    }   // end of loop over tracks

    Int_t nrows=param->GetNRow(isec);
    for (Int_t irow=0; irow<nrows; irow++) {
        AliTPCClustersRow *clrow=carray.GetRow(isec,irow);
        if (!clrow) continue;
        carray.StoreRow(isec,irow);
        carray.ClearRow(isec,irow);
    }

  } // end of loop over sectors  

  //  cerr<<"Number of made clusters : "<<nclusters<<"                        \n";
  loader->WriteRecPoints("OVERWRITE");
  
  
} // end of function

//_________________________________________________________________
void AliTPCFast::Hits2ExactClustersSector(AliRunLoader* runLoader,
					  AliTPCClustersArray* clustersArray,
					  Int_t isec) const
{
  //--------------------------------------------------------
  //calculate exact cross point of track and given pad row
  //resulting values are expressed in "digit" coordinata
  //--------------------------------------------------------

  //-----------------------------------------------------------------
  // Origin: Marian Ivanov  GSI Darmstadt, m.ivanov@gsi.de
  //-----------------------------------------------------------------
  //
  if (clustersArray==0){    
    return;
  }
  AliLoader* loader = runLoader->GetLoader("TPCLoader");
  if (!loader) {
    AliError("No TPC loader found");
    return;
  }
  if (!runLoader->GetAliRun()) runLoader->LoadgAlice();
  AliRun* aliRun = runLoader->GetAliRun();
  if (!aliRun) {
    AliError("Couldn't get AliRun object");
    return;
  }
  AliTPC* tpc = (AliTPC*) aliRun->GetDetector("TPC");
  if (!tpc) {
    AliError("Couldn't get TPC detector");
    return;
  }
  AliTPCParam* param = tpc->GetParam();
  if (!param) {
    AliError("No TPC parameters available");
    return;
  }
  //
  TParticle *particle; // pointer to a given particle
  AliTPChit *tpcHit; // pointer to a sigle TPC hit
  //  Int_t sector,nhits;
  Int_t ipart;
  const Int_t kcmaxhits=30000;
  TVector * xxxx = new TVector(kcmaxhits*4);
  TVector & xxx = *xxxx;
  Int_t maxhits = kcmaxhits;
  //construct array for each padrow
  for (Int_t i=0; i<param->GetNRow(isec);i++) 
    clustersArray->CreateRow(isec,i);
  
  //---------------------------------------------------------------
  //  Get the access to the tracks 
  //---------------------------------------------------------------
  
  TTree *tH = loader->TreeH();
  if (tH == 0x0)
    AliFatal("Can not find TreeH in folder");

  tpc->SetTreeAddress();

  Stat_t ntracks = tH->GetEntries();
  Int_t npart = aliRun->GetMCApp()->GetNtrack();
  //MI change
  TBranch * branch=0;
  if (tpc->GetHitType()>1) branch = tH->GetBranch("TPC2");
  else branch = tH->GetBranch("TPC");

  //------------------------------------------------------------
  // Loop over tracks
  //------------------------------------------------------------

  for(Int_t track=0;track<ntracks;track++){ 
    Bool_t isInSector=kTRUE;
    tpc->ResetHits();
     isInSector = tpc->TrackInVolume(isec,track);
    if (!isInSector) continue;
    //MI change
    branch->GetEntry(track); // get next track
    //
    //  Get number of the TPC hits and a pointer
    //  to the particles
    // Loop over hits
    //
    Int_t currentIndex=0;
    Int_t lastrow=-1;  //last writen row

    //M.I. changes

    tpcHit = (AliTPChit*)tpc->FirstHit(-1);
    while(tpcHit){
      
      Int_t sector=tpcHit->fSector; // sector number
      if(sector != isec){
	tpcHit = (AliTPChit*) tpc->NextHit();
	continue; 
      }

      ipart=tpcHit->Track();
      if (ipart<npart) particle=aliRun->GetMCApp()->Particle(ipart);
      
      //find row number

      Float_t  x[3]={tpcHit->X(),tpcHit->Y(),tpcHit->Z()};
      Int_t    index[3]={1,isec,0};
      Int_t    currentrow = param->GetPadRow(x,index) ;	
      if (currentrow<0) {tpcHit = (AliTPChit*)tpc->NextHit(); continue;}
      if (lastrow<0) lastrow=currentrow;
      if (currentrow==lastrow){
	if ( currentIndex>=maxhits){
	  maxhits+=kcmaxhits;
	  xxx.ResizeTo(4*maxhits);
	}     
	xxx(currentIndex*4)=x[0];
	xxx(currentIndex*4+1)=x[1];
	xxx(currentIndex*4+2)=x[2];	
	xxx(currentIndex*4+3)=tpcHit->fQ;
	currentIndex++;	
      }
      else 
	if (currentIndex>2){
	  Float_t sumx=0;
	  Float_t sumx2=0;
	  Float_t sumx3=0;
	  Float_t sumx4=0;
	  Float_t sumy=0;
	  Float_t sumxy=0;
	  Float_t sumx2y=0;
	  Float_t sumz=0;
	  Float_t sumxz=0;
	  Float_t sumx2z=0;
	  Float_t sumq=0;
	  for (Int_t index=0;index<currentIndex;index++){
	    Float_t x,x2,x3,x4;
	    x=x2=x3=x4=xxx(index*4);
	    x2*=x;
	    x3*=x2;
	    x4*=x3;
	    sumx+=x;
	    sumx2+=x2;
	    sumx3+=x3;
	    sumx4+=x4;
	    sumy+=xxx(index*4+1);
	    sumxy+=xxx(index*4+1)*x;
	    sumx2y+=xxx(index*4+1)*x2;
	    sumz+=xxx(index*4+2);
	    sumxz+=xxx(index*4+2)*x;
	    sumx2z+=xxx(index*4+2)*x2;	 
	    sumq+=xxx(index*4+3);
	  }
	  Float_t centralPad = (param->GetNPads(isec,lastrow)-1)/2;
	  Float_t det=currentIndex*(sumx2*sumx4-sumx3*sumx3)-sumx*(sumx*sumx4-sumx2*sumx3)+
	    sumx2*(sumx*sumx3-sumx2*sumx2);
	  
	  Float_t detay=sumy*(sumx2*sumx4-sumx3*sumx3)-sumx*(sumxy*sumx4-sumx2y*sumx3)+
	    sumx2*(sumxy*sumx3-sumx2y*sumx2);
	  Float_t detaz=sumz*(sumx2*sumx4-sumx3*sumx3)-sumx*(sumxz*sumx4-sumx2z*sumx3)+
	    sumx2*(sumxz*sumx3-sumx2z*sumx2);
	  
	  Float_t detby=currentIndex*(sumxy*sumx4-sumx2y*sumx3)-sumy*(sumx*sumx4-sumx2*sumx3)+
	    sumx2*(sumx*sumx2y-sumx2*sumxy);
	  Float_t detbz=currentIndex*(sumxz*sumx4-sumx2z*sumx3)-sumz*(sumx*sumx4-sumx2*sumx3)+
	    sumx2*(sumx*sumx2z-sumx2*sumxz);
	  
	  if (TMath::Abs(det)<0.00001){
	     tpcHit = (AliTPChit*)tpc->NextHit();
	    continue;
	  }
	
	  Float_t y=detay/det+centralPad;
	  Float_t z=detaz/det;	
	  Float_t by=detby/det; //y angle
	  Float_t bz=detbz/det; //z angle
	  sumy/=Float_t(currentIndex);
	  sumz/=Float_t(currentIndex);

	  AliTPCClustersRow * row = (clustersArray->GetRow(isec,lastrow));
	  if (row!=0) {
	    AliComplexCluster* cl = new((AliComplexCluster*)row->Append()) AliComplexCluster ;
	    //	  AliComplexCluster cl;
	    cl->fX=z;
	    cl->fY=y;
	    cl->fQ=sumq;
	    cl->fSigmaX2=bz;
	    cl->fSigmaY2=by;
	    cl->fTracks[0]=ipart;
	  }
	  currentIndex=0;
	  lastrow=currentrow;
	} //end of calculating cluster for given row
	
	
      tpcHit = (AliTPChit*)tpc->NextHit();
    } // end of loop over hits
  }   // end of loop over tracks 
  //write padrows to tree 
  for (Int_t ii=0; ii<param->GetNRow(isec);ii++) {
    clustersArray->StoreRow(isec,ii);    
    clustersArray->ClearRow(isec,ii);        
  }
  xxxx->Delete();
 
}


void AliTPCFast::FindTrackHitsIntersection(AliRunLoader* runLoader,
					   AliTPCClustersArray* clustersArray) const
{

  //
  //fill clones array with intersection of current point with the
  //middle of the row
  AliLoader* loader = runLoader->GetLoader("TPCLoader");
  if (!loader) {
    AliError("No TPC loader found");
    return;
  }
  if (!runLoader->GetAliRun()) runLoader->LoadgAlice();
  AliRun* aliRun = runLoader->GetAliRun();
  if (!aliRun) {
    AliError("Couldn't get AliRun object");
    return;
  }
  AliTPC* tpc = (AliTPC*) aliRun->GetDetector("TPC");
  if (!tpc) {
    AliError("Couldn't get TPC detector");
    return;
  }
  AliTPCParam* param = tpc->GetParam();
  if (!param) {
    AliError("No TPC parameters available");
    return;
  }

  Int_t sector;
  Int_t ipart;
  
  const Int_t kcmaxhits=30000;
  TVector * xxxx = new TVector(kcmaxhits*4);
  TVector & xxx = *xxxx;
  Int_t maxhits = kcmaxhits;
      
  //
  AliTPChit * tpcHit=0;
  tpcHit = (AliTPChit*)tpc->FirstHit2(-1);
  Int_t currentIndex=0;
  Int_t lastrow=-1;  //last writen row

  while (tpcHit){
    if (tpcHit==0) continue;
    sector=tpcHit->fSector; // sector number
    ipart=tpcHit->Track();
    
    //find row number
    
    Float_t  x[3]={tpcHit->X(),tpcHit->Y(),tpcHit->Z()};
    Int_t    index[3]={1,sector,0};
    Int_t    currentrow = param->GetPadRow(x,index) ;	
    if (currentrow<0) continue;
    if (lastrow<0) lastrow=currentrow;
    if (currentrow==lastrow){
      if ( currentIndex>=maxhits){
	maxhits+=kcmaxhits;
	xxx.ResizeTo(4*maxhits);
      }     
      xxx(currentIndex*4)=x[0];
      xxx(currentIndex*4+1)=x[1];
      xxx(currentIndex*4+2)=x[2];	
      xxx(currentIndex*4+3)=tpcHit->fQ;
      currentIndex++;	
    }
    else 
      if (currentIndex>2){
	Float_t sumx=0;
	Float_t sumx2=0;
	Float_t sumx3=0;
	Float_t sumx4=0;
	Float_t sumy=0;
	Float_t sumxy=0;
	Float_t sumx2y=0;
	Float_t sumz=0;
	Float_t sumxz=0;
	Float_t sumx2z=0;
	Float_t sumq=0;
	for (Int_t index=0;index<currentIndex;index++){
	  Float_t x,x2,x3,x4;
	  x=x2=x3=x4=xxx(index*4);
	  x2*=x;
	  x3*=x2;
	  x4*=x3;
	  sumx+=x;
	  sumx2+=x2;
	  sumx3+=x3;
	  sumx4+=x4;
	  sumy+=xxx(index*4+1);
	  sumxy+=xxx(index*4+1)*x;
	  sumx2y+=xxx(index*4+1)*x2;
	  sumz+=xxx(index*4+2);
	  sumxz+=xxx(index*4+2)*x;
	  sumx2z+=xxx(index*4+2)*x2;	 
	  sumq+=xxx(index*4+3);
	}
	Float_t centralPad = (param->GetNPads(sector,lastrow)-1)/2;
	Float_t det=currentIndex*(sumx2*sumx4-sumx3*sumx3)-sumx*(sumx*sumx4-sumx2*sumx3)+
	  sumx2*(sumx*sumx3-sumx2*sumx2);
	
	Float_t detay=sumy*(sumx2*sumx4-sumx3*sumx3)-sumx*(sumxy*sumx4-sumx2y*sumx3)+
	  sumx2*(sumxy*sumx3-sumx2y*sumx2);
	Float_t detaz=sumz*(sumx2*sumx4-sumx3*sumx3)-sumx*(sumxz*sumx4-sumx2z*sumx3)+
	  sumx2*(sumxz*sumx3-sumx2z*sumx2);
	
	Float_t detby=currentIndex*(sumxy*sumx4-sumx2y*sumx3)-sumy*(sumx*sumx4-sumx2*sumx3)+
	  sumx2*(sumx*sumx2y-sumx2*sumxy);
	Float_t detbz=currentIndex*(sumxz*sumx4-sumx2z*sumx3)-sumz*(sumx*sumx4-sumx2*sumx3)+
	  sumx2*(sumx*sumx2z-sumx2*sumxz);
	
	Float_t y=detay/det+centralPad;
	Float_t z=detaz/det;	
	Float_t by=detby/det; //y angle
	Float_t bz=detbz/det; //z angle
	sumy/=Float_t(currentIndex);
	sumz/=Float_t(currentIndex);
	
	AliComplexCluster cl;
	cl.fX=z;
	cl.fY=y;
	cl.fQ=sumq;
	cl.fSigmaX2=bz;
	cl.fSigmaY2=by;
	cl.fTracks[0]=ipart;
	
	AliTPCClustersRow * row = (clustersArray->GetRow(sector,lastrow));
	if (row!=0) row->InsertCluster(&cl);
	currentIndex=0;
	lastrow=currentrow;
      } //end of calculating cluster for given row
        	
  } // end of loop over hits
  xxxx->Delete();

}