#define B2DPi_cxx
#include "B2DPi.h"
#include <TH2.h>
#include <TStyle.h>
#include <TCanvas.h>

void setHistProp(TH1F* h, TString xtitle = " ", TString ytitle = " ")
{
  h->SetLineWidth(2);
  h->SetNdivisions(505,"X");
  h->SetNdivisions(505,"Y");
  h->SetXTitle(xtitle);
  h->SetYTitle(ytitle);
  h->GetXaxis()->SetTitleSize(0.05);
  h->GetYaxis()->SetTitleSize(0.05);
  h->GetXaxis()->SetLabelSize(0.05);
  h->GetYaxis()->SetLabelSize(0.05);
  h->GetXaxis()->SetTitleOffset(1.0);
  h->GetYaxis()->SetTitleOffset(1.0);
}



void B2DPi::Loop()
{
//   In a ROOT session, you can do:
//      Root > .L B2DPi.C
//      Root > B2DPi t
//      Root > t.GetEntry(12); // Fill t data members with entry number 12
//      Root > t.Show();       // Show values of entry 12
//      Root > t.Show(16);     // Read and show values of entry 16
//      Root > t.Loop();       // Loop on all entries
//

//     This is the loop skeleton where:
//    jentry is the global entry number in the chain
//    ientry is the entry number in the current Tree
//  Note that the argument to GetEntry must be:
//    jentry for TChain::GetEntry
//    ientry for TTree::GetEntry and TBranch::GetEntry
//
//       To read only selected branches, Insert statements like:
// METHOD1:
//    fChain->SetBranchStatus("*",0);  // disable all branches
//    fChain->SetBranchStatus("branchname",1);  // activate branchname
// METHOD2: replace line
//    fChain->GetEntry(jentry);       //read all branches
//by  b_branchname->GetEntry(ientry); //read only this branch
   if (fChain == 0) return;

   TFile *fout = new TFile("temp.root","RECREATE");
   TTree *newtree = fChain->CloneTree(0);

   Long64_t nentries = fChain->GetEntriesFast();

   TH1F *bmass = new TH1F("bmass","B#rightarrowD#pi Mass",60,5000,5600);
   TH1F *benergy = new TH1F("benergy","B#rightarrowD#pi Energy (GeV)",50,0,500);
   TH1F *bdecaytime = new TH1F("bdecaytime","B#rightarrowD#pi Decay Time (ps)",50,0,10);
   TH1F *bflightdist = new TH1F("bflightdist","B#rightarrowD#pi Flight Distance (mm)",50,0,50);

   cout << " Number of entries = " << nentries << endl;
   
   Long64_t nbytes = 0, nb = 0;
   //for (Long64_t jentry=0; jentry<nentries;jentry++) {
     for (Long64_t jentry=0; jentry<100;jentry++) {
      Long64_t ientry = LoadTree(jentry);
      if (ientry < 0) break;
      nb = fChain->GetEntry(jentry);   nbytes += nb;

      bmass->Fill(B_M);
      benergy->Fill(B_PE/1000.0);
      bdecaytime->Fill(B_TAU*1000);
      bflightdist->Fill(B_FD_OWNPV);

      newtree->Fill();
      

      // if (Cut(ientry) < 0) continue;
   }

   fout->Write();

   gStyle->SetPadLeftMargin(0.13);
   gStyle->SetPadBottomMargin(0.13);

   setHistProp(bmass, "Mass (GeV/c^{2})", "Number/10 MeV/c^{2}");
   setHistProp(benergy, "Energy (GeV)", "Number/10 GeV");
   setHistProp(bdecaytime, "Decay Time (ps)", "Number/0.2 ps");
   setHistProp(bflightdist, "Distance (mm)", "Number/mm");   


   TCanvas *c = new TCanvas("c","B Decay Properties",700,700);
   c->Divide(2,2);
   c->cd(1);
   bmass->Draw();
   c->cd(2);
   benergy->Draw();
   c->cd(3);
   bdecaytime->Draw();
   c->cd(4);
   bflightdist->Draw();
   


}