#include "TCanvas.h"
#include "TPad.h"
#include "TMultiGraph.h"
#include "TGraph.h"
#include "TGraphErrors.h"
#include "TAxis.h"
#include "TLegend.h"
#include "TLatex.h"
#include "TROOT.h"

#include <cstdlib> 
void corona() {
	gStyle->SetOptFit();
	const char *datain = "C:/corona.txt";
	const char *dataout = "C:/root_v6.20.00/corona.pdf";

	TCanvas *c01 = new TCanvas("c01","multigraph",1280,1024);
	float offx=1.3;
	float offy=1.7;
	float margr=0.08;
	float w=3;
	float margl=0.12;
	gPad->SetLeftMargin(margl);
	gPad->SetRightMargin(margr);
	
	TDatime T0(2020, 3, 10, 0, 0, 0);
   int X0 = T0.Convert();
   gStyle->SetTimeOffset(X0);
   // Define the lowest histogram limit as 2020, February 24rd
   TDatime T1(2020, 2, 24, 0, 0, 0);
   int X1 = T1.Convert()-X0;
   // Define the highest histogram limit as 2020, June 7th
   TDatime T2(2020, 6, 7, 0, 0, 0);
   int X2 = T2.Convert(1)-X0;
	
	TGraphErrors *gamma = new TGraphErrors(datain,"%lg %lg");
	gamma->SetMarkerColor(kBlue);
	gamma->SetLineColor(kBlue);
	gamma->SetMarkerStyle(23);
	gamma->SetLineWidth(10);

	TF1 *fitspettro = new TF1("fitspettro", "gaus");
	gamma->Fit("fitspettro");
	fitspettro->SetRange(0.,100);
	fitspettro->Draw();
	gamma->Draw("L");
	
	fitspettro->SetTitle("Covid-19 cases");
	fitspettro->GetXaxis()->SetTitle("Day");
	fitspettro->GetYaxis()->SetTitle("Cases");
	fitspettro->GetYaxis()->SetTitleOffset(offy);
	fitspettro->GetXaxis()->SetTitleOffset(offx);
	fitspettro->GetXaxis()->SetTimeDisplay(1);
	fitspettro->GetXaxis()->SetTimeFormat("%m/%d");
	TLegend* leg = new TLegend(0.15, 0.7, .25, .75);
	leg->SetHeader("Legend");
	leg->SetNColumns(1);
	leg->AddEntry(gamma, "Data", "l");
	leg->AddEntry(fitspettro, "Fit", "l");  
	leg->Draw(); 
	gPad->Update();
	TPaveStats *stat = (TPaveStats*)gamma->GetListOfFunctions()->FindObject("stats");
	stat->SetTextColor(kBlue);
	stat->SetX1NDC(0.80); stat->SetX2NDC(0.98);
	stat->SetY1NDC(0.77); stat->SetY2NDC(0.92);
	c01->Print(dataout);
}