// general
#include "TH1.h"
#include "TH2F.h"
#include "TFile.h"
#include "TTree.h"
#include "TCanvas.h"
#include "TSystem.h"
#include "TF1.h"
#include "TKey.h"
#include "TH1F.h"
#include "TStyle.h"
#include "TProfile.h"
#include "TLegend.h"
#include "TLine.h"
#include "TArrow.h"
#include "TLatex.h"
#include "TGraph.h"
#include "TGraphErrors.h"
#include "TFormula.h"
#include "TAxis.h"
#include "TRandom3.h"
#include "TMath.h"
#include "THStack.h"

#include <cmath>
#include <iostream>
#include <stdio.h>
#include <fstream>
#include <sstream>
#include <vector>
#include <algorithm>
void ReBin(TH1F * &h);
void ReBin(TH1F * &h, TAxis * &ax);
void ReBin(TH1F * &h, TAxis * &ax,int entries_);
void ReBinTTbar(TH1F * &h);
void rebin(TH1F * &h);

void Rebin2()
{
  using namespace std;
//CLASS , CLASS
//  setTDRStyle();
  gStyle->SetOptStat(0);

	TString fileName = "filein.root";
        TFile *target = new TFile("fileout_Bin.root","recreate" );
	TFile *file = TFile::Open(fileName);

	if (!file) abort();

   TFile *first_source = TFile::Open(fileName);
  TString path ((char *) strstr (target->GetPath (), ":"));
  path.Remove (0, 2);
	    
   TAxis *axis ;
   TH1F * ht = (TH1F*) file->Get("MVA_MLP_TT");
   int entries = ht->GetEntries();
   ReBinTTbar(ht);
   cout<<" OK, done with the TTJets......"<<endl; 
   TFile *taxisFile;
   taxisFile = new TFile ("TT_axis.root", "recreate");
   axis = ht->GetXaxis();
   taxisFile->cd ();
   axis->Write();
   taxisFile->Write ();
   ht->Write();
cout<<"  before  "<<axis->GetNbins()<<"  "<<ht->GetNbinsX()<<endl;
   taxisFile->Close ();
   target->cd();
   ht->Write();


  first_source->cd (path);
   
  TDirectory *current_sourcedir = gDirectory;
  //gain time, do not add the objects in the list in memory
  Bool_t status = TH1::AddDirectoryStatus ();
  TH1::AddDirectory (kFALSE);

  // loop over all keys in this directory
  TChain *globChain = 0;
  TIter nextkey (current_sourcedir->GetListOfKeys ());
 TKey *key, *oldkey = 0;
  while ((key = (TKey *) nextkey ())) {

    //keep only the highest cycle number for each key
    if (oldkey && !strcmp (oldkey->GetName (), key->GetName ()))
      continue;

    first_source->cd (path);
    TObject *obj = key->ReadObj ();
   
    TLegend *legend_c1 = new TLegend (0.35, 0.90, 0.80, 0.70);
    

    if (obj->IsA ()->InheritsFrom ("TH1F")) {
      TH1F *h1 = (TH1F *) obj;
      string name=h1->GetName();

   if (name!="MVA_MLP_TT"){
        ReBin(h1,axis,entries);
	target->cd();
        h1->Write();
   }

}
}
        target->Write();
	target->Close();


}

void ReBinTTbar(TH1F * &h){
float binContent[100];
binContent{100}=0;

TH1F *histo;
histo=h;

int count_new_bins=0;
int last_big_bin=0;
int merge_up_to_this_bin=0;
for (int nbbs=0;nbbs<int(h->GetNbinsX());nbbs++){
}
for  (unsigned int nb = 0;nb<int(h->GetNbinsX());nb++){
//if more than 10 entries, is just fine

float  small_bins=0;	
if ( h->GetBinContent(nb)>10 && h->GetBinContent(nb-1)<10 && h->GetBinLowEdge(nb-1)<0){
merge_up_to_this_bin=nb-1;
}

	
if (h->GetBinContent(nb)<10 && h->GetBinLowEdge(nb)>0){
last_big_bin=nb-1;
break;
}
}

for (int k=0;k<merge_up_to_this_bin+1;k++){
small_bins+=h->GetBinContent(k);
}


for  (unsigned int n_big = merge_up_to_this_bin+1;n_big<last_big_bin+1;n_big++){

count_new_bins++;
binContent[count_new_bins] = float(h->GetBinContent(n_big));
}

binContent[1]+=small_bins;


for  (unsigned int n_small = last_big_bin+1;n_small<int(h->GetNbinsX());n_small++){
binContent[count_new_bins+1]+= float(h->GetBinContent(n_small));
	}



TH1F *histo_binned;
histo_binned = new TH1F("","",count_new_bins-1,0,2);

histo_binned->SetName(h->GetName());
histo_binned->SetTitle(h->GetTitle());
//merge the 1-rst

 histo_binned->SetBinContent(merge_up_to_this_bin+1,small_bins);
 for (unsigned int nbb=1;nbb<count_new_bins+1;nbb++){
 histo_binned->SetBinContent(nbb,binContent[nbb]);
 cout<<" Filling the new histo  "<<nbb<<" content "<<binContent[nbb]<<"  low edge   "<<h->GetBinLowEdge(nbb)<<endl;
 }
histo_binned->Sumw2();
h=histo_binned;
}


void ReBin(TH1F * &h, TAxis * &axis_,int entries){

TH1F *histo;
histo=h;


cout<<"  now  "<<axis_->GetNbins()<<endl;
TH1F *histo_binned = new TH1F(h->GetName(),h->GetTitle(),axis_->GetNbins(), axis_->GetXbins ()->fArray );

vector <float > values;
values.clear();

Double_t *xbins = new Double_t[entries+1];
Int_t k=0;

for (Int_t i=1;i<=axis_->GetNbins();i++) {

	Int_t y = (Int_t)h->GetBinContent(i);
	if (y <=0) continue;
	Double_t dx = axis_->GetBinWidth(i)/y;
	Double_t xmin = axis_->GetBinLowEdge(i);
	for (Int_t j=0;j<y;j++) {
		xbins[k] = xmin +j*dx;
	         values.push_back(xbins[k]);
		//printf("xbins[%d]= %g\n",k,xbins[k]);
		k++;
	}

}

for (int k=0;k<values.size();k++){
	histo_binned->Fill(values[k]);
}

h=histo_binned;

cout<<h->GetName()<<"  "<<h->GetNbinsX()<<"  "<<histo_binned->GetNbinsX()<<"  "<<axis_->GetNbins()<<"  "<<axis_->GetXbins ()->fArray<<endl;
      //new rebinned histogram should have about 10 entries per bin
      //   hnew->FillRandom("gaus",10*nentries);
      //      hnew->Draw();

}