#include "TFile.h"
#include "TTree.h"
#include "TCanvas.h"
#include "TH1F.h"
#include <iostream>

using namespace std;

void readEvents(){
  
  //TASK 1*************************************************************
  //Load the file

  //Get the tree(called POOLCollectionTree) from the file

  //Get entries of the file

  //Here, YOU print the number of entries the file found
  

  //TASK 2**************************************************************
  // create local variables for the tree's branches
  // We need Float_t type for LooseMuonsPhi1, LooseMuonsPt1, LooseMuonsEta2, LooseMuonsPhi2,LooseMuonsPt2
  UInt_t NLooseMuons;
  Float_t LooseMuonsEta1;
  Float_t LooseMuonsPhi1;
  Float_t LooseMuonsPt1;
 
  //Here YOU define a Float_t for LooseMuon objects
 

  //Task 3**************************************************************  
  // set the tree's braches to the local variables
  tree->SetBranchAddress("NLooseMuon", &NLooseMuons);
  tree->SetBranchAddress("LooseMuonEta1", &LooseMuonsEta1);
  tree->SetBranchAddress("LooseMuonPhi1", &LooseMuonsPhi1);
  tree->SetBranchAddress("LooseMuonPt1", &LooseMuonsPt1);

  //Here YOU set a tree's branch to LooseMuonPt, Eta, Phi
  

  //Task 4**************************************************************
  //declare some histograms
  //declare a histogram called muPt, with 50 bins, and range from 0 to 200
  TH1F *muPt = new TH1F("muPt", ";p_{T} [GeV/c];Events", 50, 0, 200);

  //declare a histogram called muEta, with 50 bins and range -3 to 3
  TH1F *muEta = new TH1F("muEta", ";#eta;Events", 50, -3, 3);

  //declare a histogram called muPhi with 50 bins and range from -4 to 4
  TH1F *muPhi = new TH1F("muPhi", ";#phi;Events", 50, -4, 4);
 
  //declare a histogram called muE with 50 bins and range from 0 to 200
  TH1F *muE = new TH1F("muE", ";Energy;Events", 50, 0, 200);
  
  // Here, YOUdeclare a histogram called Zmass with 50 bins and range from 0 to 200


  // Here, YOU declare a histogram called ZmassBkg with 50 bins and range from 0 to 200
  

  // loop over each entry (event) in the tree
  for( int entry=0; entry<10000; entry++ ){
    //Task A**************************************************************

    
    // check that the event is read properly


    //Task B**************************************************************    
    // only look at events containing at least 2 leptons
    
    // require the leptons to be greater than 20 GeV
  
    //here YOU require LooseMuonsPt2 > 20 GeV
    
    // make a LorentzVector from the muon
    

    //here YOU define a LorentzVector for Muons2
    
    // print out the details of an electron every so often
    
    //Task C***********************************************************
    // fill our histograms

   
    //Here, YOU define the Z boson vector as a sum of the 2 muon vectors

    //Fill the Zmass and ZmassBkg histograms 
    
  }//THIS IS THE END OF OUR ENTRIES LOOP
  

  //Task 5
  // Here, YOU draw the Zmass distribution

  
  // make a ROOT output file to store your histograms
  TFile *outFile = new TFile("histograms.root", "recreate");
  muPt->Write();
  muEta->Write();
  muPhi->Write();
  muE->Write();

  //Here, YOU write the Zmass and  ZmassBkg histogram


}// END OF readEventsLoop