#include <iostream> 
 #include <vector>
 #include <limits>
 #include "TChain.h"
 #include "TCut.h"
 #include "TDirectory.h"
 #include "TH1F.h"
 #include "TH1.h"
 #include "TMath.h"
 #include "TFile.h"
 #include "TStopwatch.h"
 #include "TROOT.h"
 #include "TSystem.h"
 #include "TString.h"
 #include "TLatex.h"
 using namespace std;


void TMVAplot_RocCurve(){	
	
	TFile file_S("TMVAb_privateMCs_16Vars_40Epochs_Adam_tanh15_b1_sb.root");
	
	TH1* hist_eff_S = (TH1*)file_S.Get("TMVAb15_b1_sb/Method_PyKeras/PyKeras/MVA_PyKeras_effBvsS"); 

	int nBins = hist_eff_S->GetNbinsX(); cout << "nBins = " << nBins << endl;
	double x[nBins];
	double y_S[nBins];

	for (Int_t i=0; i<nBins; i++) {
		x[i] = (double)i/nBins;   
		y_S[i] = hist_eff_S->GetBinContent(i);
	}
	
//=============================================== C0 ===================================================================================

	TCanvas *c0 = new TCanvas("c0","c0",1200,800);
		
	    TGraph *grS = new TGraph(nBins,y_S,x); 
	    grS->SetLineWidth(2);         
	    grS->SetLineColor(kGreen+1); 
	    grS->GetXaxis()->SetTitle("Signal efficiency");
	    grS->GetYaxis()->SetTitle("Background rejection");   
	    grS->SetMinimum(0.0);  
		grS->SetMaximum(1.0); 

		TLine *line = new TLine(0,0,0.8,0.8); //1.0,1.0
  		line->SetLineColor(kBlack); line->SetLineWidth(2); line->SetLineStyle(5);

		float AUC, IS_t;
		
		IS_t = hist_eff_S->Integral(0,nBins,"width");  
		AUC = 1 - IS_t;
		
		auto legend0 = new TLegend(0.5,0.1,0.9,0.3);
			legend0->AddEntry(grS,  TString::Format("tH vs combined background, AUC=%.4f", AUC),"l");
	
	c0->cd();
	c0->SetGrid();	
 	grS->Draw(); 
 	legend0->Draw();
 	line->Draw();

}