using namespace RooFit;
using namespace std;

void lambda_sig() {
    // Create a TChain to read the data from ROOT files
    TChain *chain = new TChain("tree");
    chain->Add("/home/g_vikas_raj/Downloads/root/SVD/splots_2/test_lambda/unbinned/ok/unbinned/lambda_draw_unb_all.root");

    // Define variables for the fit
    RooRealVar InvM("InvM", "M_{p^{+}#pi^{-}}", 1.1, 1.13,"GeV/c^{2}"); // Adjust the range accordingly
    RooRealVar isSignal("isSignal", "Signal Indicator", 0.0, 1.0);

    // Create a RooDataSet from the chain with the desired cuts
    RooDataSet data("data", "Dataset with isSignal == 1", chain, RooArgSet(InvM, isSignal), "isSignal==1");

     RooRealVar mean1("mean1", " mean1", 1.116321, 1.1105, 1.122); //1.116254
     RooRealVar sigma1("sigma1", "#sigma_{1}", 0.004981, 0., 0.01); //0.003077
     RooGaussian gauss1("gauss1", "gauss1", InvM, mean1, sigma1);
     
     
     RooRealVar r1("r1", "r1", 0.332,0.0,1.0); //0.424
     RooRealVar r2("r2", "r2", 0.2535,0.0,1.0); //0.3262
     RooFormulaVar sigmaL1("sigmaL1", "r1*sigma1",RooArgSet(r1, sigma1));
     RooFormulaVar sigmaR1("sigmaR1", "r2*sigma1",RooArgSet(r2, sigma1));
     RooBifurGauss Bgauss1("Bgauss1", "BGauss1", InvM, mean1, sigmaL1,sigmaR1);
     
     
     RooRealVar d("d", "d", -0.0004457,-0.01, 0.01); //-0.0003919
     RooRealVar r3("r3", "r3", 0.1222,0.0,1.0); // 0.1767
     RooRealVar r4("r4", "r4", 0.1029,0.0,1.0); // 0.1492
     
     RooFormulaVar mean2("mean2", "mean1+d",RooArgSet(mean1, d));
     RooFormulaVar sigmaL2("sigmaL2", "r3*sigma1",RooArgSet(r3, sigma1));
     RooFormulaVar sigmaR2("sigmaR2", "r4*sigma1",RooArgSet(r4, sigma1));
     RooBifurGauss Bgauss2("Bgauss2", "BGauss2", InvM, mean2, sigmaL2,sigmaR2);
     
     
     RooRealVar frac1("frac1", "frac1", 0.3815,0.0,1.0 ); //0.3815
     RooRealVar frac2("frac2", "frac2", 0.8635,0.0,1.0 ); //0.8635
     
     RooAddPdf model1("model1","Bgauss1 + Bgauss2 ",RooArgList(Bgauss1,Bgauss2),RooArgList(frac1));
     RooAddPdf signal("signal","model1 + gauss1",RooArgList(model1,gauss1),RooArgList(frac2));


    // Perform the fit
    RooFitResult *result = signal.fitTo(data, Save(true));

    // Save the fit result to a file
    //TFile outputFile("fit_result.root", "RECREATE");
    //result->Write();
    //outputFile.Close();

    // Plot the result
    RooPlot *frame = InvM.frame();
    data.plotOn(frame);
    signal.plotOn(frame);
    
    signal.paramOn(frame);

    TCanvas *canvas = new TCanvas("canvas", "canvas", 800, 600);
    frame->Draw();
    //canvas->SaveAs("fit_plot_4.png");
    
    double chisquare = frame->chiSquare();
    cout<<"chisquare = "<<chisquare<<endl; 
    cout<<"All done"<<endl;
}