#define Analysis_cxx
#include "Analysis.h"
#include <TH2.h>
#include <TStyle.h>
#include <TCanvas.h>

void Analysis::Loop()
{

   if (fChain == 0) return;

   Long64_t nentries = fChain->GetEntriesFast();
   cout<<"Number of entries to analyse =\t"<<nentries<<endl;
   Long64_t nbytes = 0, nb = 0;
   //Define Histograms here(Outside the loop)
   TH1F *histo_njet = new TH1F("histo_njet", "NumberOfJets", 10, 0, 10);
   TH1F *histo_jetpt = new TH1F("histo_jetpt", "Transverse momentum of all jets", 100, 0, 2000);
    TH1F *histo_leadingjetpt = new TH1F("histo_leadingjetpt", "Transverse momentum of leading jet", 100, 0, 2000);
    TH1F *histo_subleadingjetpt = new TH1F("histo_subleadingjetpt", "Transverse momentum of sub leading jet", 100, 0, 2000);
    TH1F *hist_mjj  = new TH1F("hist_mjj", "Invariant mass", 100, 0, 10000);

   //Here the Event loop starts
   for (Long64_t jentry=0; jentry<nentries;jentry++)
     {
       Long64_t ientry = LoadTree(jentry);
       if (ientry < 0) break;
       nb = fChain->GetEntry(jentry);   nbytes += nb;

       if(jentry%50000==0)cout<<"Number of events analysed  =\t"<<jentry<<endl;

       //Fill histograms inside event loop(It will fill histogram event by event)
       histo_njet->Fill(njets);
       
       // Loop Over Jets
       for (Int_t j = 0; j< jet_E->size(); j++)
	 {
	   histo_jetpt->Fill(jet_pt->at(j));
	 }      
      
       //For leading  & subleading jets
       
       if (jet_pt->size()<2)continue;//crosscheck
       

       histo_leadingjetpt->Fill(jet_pt->at(0));
       histo_subleadingjetpt->Fill(jet_pt->at(1));
	
       

       //To calculate all the kinematics of leading/subleading jets: We use Lorentz Factor
       TLorentzVector LeadJet;
       TLorentzVector SubLeadJet;
       TLorentzVector JetSum;

       LeadJet->SetPtEtaPhiE(jet_pt->at(0), jet_eta->at(0), jet_phi->at(0), jet_E->at(0));
       SubLeadJet->SetPtEtaPhiE(jet_pt->at(1), jet_eta->at(1), jet_phi->at(1), jet_E->at(1));
       JetSum=LeadJet+SubLeadJet;//Dijet

 
       //Calculate Dijet Kinematics here
       hist_mjj->Fill(JetSum.M());
       
     }//event loop

   //Plotting/Saving outside event loop

   TFile Outfile("Output.root","RECREATE");
   histo_njet->Write(); 
   histo_jetpt->Write(); 
   histo_leadingjetpt->Write();
   histo_subleadingjetpt->Write();
   hist_mjj->Write();
   Outfile.Close();  


// select postscript output type
   // type = 111   portrait  ps
   // type = 112   landscape ps
   // type = 113   eps
   TCanvas c1("c1","canvas",800,600);
   TPostScript ps("myfile.ps",112);
   ps.Range(16,24);
   //Picture 1 on Page 1
   //   ps->NewPage();
   histo_njet->Draw();
   c1.Update();
   //Picture 2 on Page 2
   // ps->NewPage();
   histo_jetpt->Draw();
   c1.Update();
   //Picture 3 on Page 3
   //ps->NewPage();
   histo_leadingjetpt->Draw();
   c1.Update();
   //Picture 4 on Page 4
   //ps->NewPage();
   histo_subleadingjetpt->Draw();
   c1.Update();
   //Picture 5 on Page 5
   //ps->NewPage();
   hist_mjj->Draw();
   c1.Update();
   ps.Close();
   
   
}