// ----------------------------------------------------------------------------
// $Id: root_readMultF.C,v 1.5 2001/09/20 01:46:35 toshi Exp $
// ----------------------------------------------------------------------------
//
// Run Fast MC interactively with Root
// read multi root files
//
//     04/26/2001 Toshi
//
// :: How to run ::
// 
// 1) to call the root, type   
//    
//     root
//
// 2)
//     root [0]  .x root_readMultiF.C
// 
// .. that's it.
//
// For example, if you like to run 300 events, type like
//     root [0]  .x root_readMultiF.C(300)
//

Int_t root_readMultF(Int_t nEvent=500) {

  gROOT->Reset();

  TString parfile_dir;
  parfile_dir += gSystem->Getenv("LCDROOT")   ;parfile_dir += "/";
  parfile_dir += "ParFiles/";

  // In order to refer to shareable libraries in this simple form,
  // include their paths in a .rootrc file.
  gSystem->Load("libLCDEvent");
  gSystem->Load("libLCDRootAppsUtil");
  gSystem->Load("libLCDFastMC");

  LCDEvent* event=new LCDEvent();

  //--->SetUp...
  TChain chain("T");
  // Please input your root file(s) here 
  // For example, using chain, so as to add one or more root files
  chain.Add("test.root");
  //chain.Add("test1.root");
  //chain.Add("test2.root");
  chain.SetBranchAddress("LCDEvent", &event);

  // Open detector parameter file
  Char_t* geomFile = 
    "SDMar01.par"; // SD
  //"LDMar01.par"; // LD
  TString s_geomFile(parfile_dir);
  s_geomFile += geomFile;
  FILE* m_geomfile =  fopen(s_geomFile.Data(),"r");
  LCDGetParameters gp(m_geomfile);
  fclose(m_geomfile);

  // Tracking smearing parameter file
  Char_t* smearFile = 
    "lookup_silicon.nobmcon";
  //"lookup_large.nobmcon";
  TString s_smearFile(parfile_dir);
  s_smearFile += smearFile;

  // Initialize FastMC
  LCDFastMC fmc(&gp,s_smearFile.Data(),event); 
  // If you don't want the Cluster merging
  //fmc.SetNoClusterMerge();

  // Define a histogram or two
  TH1F *ClsMult = new TH1F("ClsMult","Cluster Multiplicity",50, 0.0, 200.0);
  TH1F *ClsE    = new TH1F("ClsE","Cluster Energy",50, 0.0, 50.0);
  TH1F *TrkMult = new TH1F("TrkMult","Track Multiplicity",50, 0.0, 100.0);
  TH1F *TrkE    = new TH1F("TrkE","Track Energy",50, 0.0, 50.0);


  // Event loop
  Int_t iEvent;
  for (iEvent=0 ; iEvent < nEvent ; iEvent++) {
    if(!T.GetEvent(iEvent)) break;    // Read an event from root file(s)
    fmc.Doit();                        // Through FastMC
      
    // Look at CLusters. Can access them by the [] operator.
    Int_t nClusters = event->ClusterLst()->GetEntries();
    ClsMult->Fill(nClusters);
      
    for (Int_t iClus = 0; iClus < nClusters; iClus++) {
      LCDCluster* cls = (LCDCluster*)event->ClusterLst()->At(iClus);
      if (cls) {
	Double_t     eClus     = cls->GetEnergy();	
	// Histogram energies
	ClsE->Fill(eClus);
      }
    }
    
    // Look at tracks. Can access them by the [] operator.
    Int_t nTracks = event->Tracks()->GetEntries();
    TrkMult->Fill(nTracks);
    
    // Track loop    
    for (Int_t ntrk=0; ntrk<nTracks; ntrk++) {
      LCDTrack* trk = (LCDTrack*)event->Tracks()->At(ntrk);
      if(trk) {
	TVector3 tP3 = trk->GetMomentum();
	// Histogram energies
	TrkE->Fill(TMath::Sqrt(tP3.Mag2() + 0.1396*0.1396));
      }
	
    }

  }

  ClsMult->SetFillColor(4);
  ClsE->SetFillColor(4);
  TrkMult->SetFillColor(4);
  TrkE->SetFillColor(4);

  TCanvas *c1 = new TCanvas("c1", "c1", 600, 600);
  c1->Divide(2,2);
  c1->cd(1); ClsMult->Draw("B");
  c1->cd(2); ClsE->Draw("B");
  c1->cd(3); TrkMult->Draw("B");
  c1->cd(4); TrkE->Draw("B");

  return iEvent;
}