using namespace RooFit;


void Fit_weights() {



 //Defining Fit Model
// --- Observable ---
RooRealVar mes("mB","m_{B} (GeV/c^{2})",6.00,6.500) ;
RooRealVar s12("s12","s12 [GeV/c^{2}]^{2}",0.,50.) ;
RooRealVar s23("s23","s23 [GeV/c^{2}]^{2}",0.,50.) ;

RooRealVar eventweight("weight","weight",0.0,1.0);
//RooRealVar eventweight("weight","weight",2);



// Partially Reconstructed, using CONVOLUTION //

RooRealVar m0("m0","m_0 (GeV/c^{2})",6.1,6,6.5) ;
RooRealVar slope("slope","slope",-25,-50,10) ;
RooGaussian myGaus("resolution","gauss model",mes,RooFit::RooConst(0.0),RooFit::RooConst(0.021385));
RooArgusBG bkgArg("bkgArg","Argus Bkg",mes,m0,slope);

 RooFFTConvPdf PartReco( "PartReco", "", mes, bkgArg, myGaus );
 PartReco.setBufferFraction(0.5);

//RooFFTConvPdf PartReco2( "PartReco2", "", mes, bkgArg, myGaus );
// PartReco2.setBufferFraction(0.3);
//RooFFTConvPdf PartReco3( "PartReco3", "", mes, bkgArg, myGaus );
 //PartReco3.setBufferFraction(0.3);



// Combine altogether

RooRealVar Nsig("Nsig","signal evts",3000,0,2000000);
RooRealVar Ncomb("Ncomb","comb bkg evts",1000,0,100000);

 // extended likelihood PDFs:

//RooExtendPdf sige("sige","sige",signal,Nsig) ;
//RooExtendPdf Combe("Ext Comb","Ext Comb",Comb,Ncomb) ;
RooExtendPdf PartRecoSum("PartRecoSum"," ",PartReco,Ncomb);

//Combine:
//RooAddPdf sum("sum","g+p1",RooArgList(sige,Combe));
// Signal only: to be used for the matched Monte Carlo

RooAddPdf sum("sum","PartReco",RooArgList(PartRecoSum));

 // ********* READING DATA from NTUPLE and filling RooDataSet object ****** \\

TFile *f = TFile::Open("tree1.root");
TTree *treedata = (TTree*)f->Get("DecayTree");


 RooDataSet *dataTemp = new RooDataSet("dataTemp","dataTemp",RooArgSet(mes,s12,s23));


 Double_t Bmass,s12_DTF,s23_DTF;

    Bool_t B_L0HadronDecision_TOS1;
    Bool_t B_L0Global_TIS1;
    Bool_t B_Hlt1TrackAllL0Decision_TOS1;
    Bool_t B_Hlt2Topo2BodyBBDTDecision_TOS1;
    Bool_t B_Hlt2Topo3BodyBBDTDecision_TOS1;
    Bool_t B_Hlt2Topo4BodyBBDTDecision_TOS1;

    Double_t BDT;
    Double_t effpid;

    Bool_t Muon1,Muon2,Muon3;


    treedata->SetBranchAddress("B_L0HadronDecision_TOS",&B_L0HadronDecision_TOS1);
    treedata->SetBranchAddress("B_L0Global_TIS",&B_L0Global_TIS1);
    treedata->SetBranchAddress("B_Hlt1TrackAllL0Decision_TOS",&B_Hlt1TrackAllL0Decision_TOS1);
    treedata->SetBranchAddress("B_Hlt2Topo2BodyBBDTDecision_TOS",&B_Hlt2Topo2BodyBBDTDecision_TOS1);
    treedata->SetBranchAddress("B_Hlt2Topo3BodyBBDTDecision_TOS",&B_Hlt2Topo3BodyBBDTDecision_TOS1);
   treedata->SetBranchAddress("B_M",&Bmass);
   treedata->SetBranchAddress("s12_DTF",&s12_DTF);
   treedata->SetBranchAddress("s23_DTF",&s23_DTF);
    treedata->SetBranchAddress("BDT_KKpi2011_total",&BDT);

    treedata->SetBranchAddress("EffPidStrip2",&effpid);

   treedata->SetBranchAddress("d1_isMuon",&Muon1);
   treedata->SetBranchAddress("d2_isMuon",&Muon2);
   treedata->SetBranchAddress("d3_isMuon",&Muon3);

Long64_t nentries = treedata->GetEntries();


 cout<<"Entries data: "<<nentries<<endl;


 for (Long64_t i=0;i<nentries;i++) {
   treedata->GetEntry(i);

    if (i%100000 == 0) {
      cout << "Finished processing " << i << " events." << endl;
    }

      if ((B_L0HadronDecision_TOS1 == 1 || B_L0Global_TIS1 == 1) && (B_Hlt1TrackAllL0Decision_TOS1>0) && (B_Hlt2Topo2BodyBBDTDecision_TOS1>0 || B_Hlt2Topo3BodyBBDTDecision_TOS1>0 || B_Hlt2Topo4BodyBBDTDecision_TOS1>0) && (Bmass > 6000) && (Bmass < 6500) && (BDT > 0.04)) {

     if ((Muon1 == 0) && (Muon2 == 0) && (Muon3 == 0)) {

     mes = Bmass*0.001;
     s12 = s12_DTF;
     s23 = s23_DTF;
     eventweight = effpid;		
     dataTemp->add(RooArgSet(mes,s12,s23));

/*
    if (Bmass > 6200) {
         eventweight = effpid;		
    } else {
         eventweight = 2;
    }
*/
}
}

 }

dataTemp->addColumn(eventweight)

RooDataSet *wdata = new RooDataSet("wdata", "wdata",*dataTemp->get(),RooFit::Import(*dataTemp),RooFit::WeightVar("eventweight"));


cout << "Dataset cloned." << endl;

// CALLING THE FITTER:

mes.setRange("partreco",6,6.5);
 
RooFitResult* fitRes = sum.fitTo(*wdata, RooFit::Save(true),RooFit::SumW2Error(kTRUE),RooFit::Strategy(2),RooFit::Range("partreco"));

cout << "Fit Result successful" << endl;


// PLOTTING THE RESULTS (FUNCTION, FITTED FUNCTION PARAMETERS AND DATA)

RooPlot* xframe2 = mes.frame(100);
wdata->plotOn(xframe2,RooFit::DataError(RooAbsData::SumW2));
//sum.plotOn(xframe2);
//sum.paramOn(xframe2,wdata);
  xframe2->GetXaxis()->SetTitleSize(0.06);
  xframe2->GetXaxis()->SetLabelSize(0.05);
  xframe2->GetXaxis()->SetTitleFont(62);
  xframe2->GetXaxis()->SetLabelFont(62);
  xframe2->GetXaxis()->CenterTitle();
  xframe2->GetYaxis()->SetTitleSize(0.06);
  xframe2->GetYaxis()->SetLabelSize(0.05);
  xframe2->GetYaxis()->SetTitleFont(62);
  xframe2->GetYaxis()->SetLabelFont(62);
  xframe2->GetYaxis()->CenterTitle();
  xframe2->GetYaxis()->SetTitle("Entries");
 xframe2->SetTitle("");
xframe2->Draw();


}