#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <TRandom3.h>
#include <TH1D.h>
#include <TF1.h>
#include <TCanvas.h>
#include <RooFit.h>
#include <RooFFTConvPdf.h>
#include <RooDataHist.h>
#include <RooHistPdf.h>
#include <RooGaussian.h>
#include <RooRealVar.h>
#include <RooArgSet.h>
#include <RooArgList.h>

int main ( int n_args, const char** args )
{
	long n_sig5 = 1000;
	long n_sig3 = 1000;
	if ( n_args > 1 )  n_sig5 = atoi( args[1] );
	if ( n_args > 2 )  n_sig3 = atoi( args[2] );
	TRandom3* num_gen = new TRandom3( 0 );

	TH1D* hist_sig3 = new TH1D( "hist_sig3", "", 40, -20, 20 );
	hist_sig3 -> Sumw2( );
	for ( int i=0; i<n_sig3; i++ )
		hist_sig3 -> Fill( num_gen->Gaus(0,3) );

	TH1D* hist_sig5 = new TH1D( "hist_sig5", "", 40, -20, 20 );
	hist_sig5 -> Sumw2( );
	for ( int i=0; i<n_sig5; i++ )
		hist_sig5 -> Fill( num_gen->Gaus(0,5) );

	RooRealVar* function_range = new RooRealVar( "function_range", "", -20, 20 );
	RooDataHist* roohist_sig5 = new RooDataHist (
			"roohist_sig5", "roohist_sig5", *function_range, RooFit::Import(*hist_sig5) );
	RooDataHist* roohist_sig3 = new RooDataHist (
			"roohist_sig3", "roohist_sig3", *function_range, RooFit::Import(*hist_sig3) );
	RooHistPdf* roopdf_sig3 = new RooHistPdf (
			"roopdf_sig3", "sig3-pdf", *function_range, *roohist_sig3 );
	RooRealVar* g_mean = new RooRealVar( "g_mean", "", 0.0 );
	RooRealVar* g_sigma = new RooRealVar( "g_sigma", "", 2.5, 0.1, 6.0 );
	RooGaussian* g_smearing = new RooGaussian(
			"g_smearing", "gauss-fit", *function_range, *g_mean, *g_sigma );
	RooFFTConvPdf* conv_pdf = new RooFFTConvPdf(
			"conv_pdf", "conv-pdf", *function_range, *roopdf_sig3, *g_smearing );
	conv_pdf -> fitTo ( *roohist_sig5, RooFit::Save( ), RooFit::Range( -20, 20 ) );

	TF1* fit_func = conv_pdf->asTF(
			*function_range, RooArgList( *g_mean, *g_sigma ), *function_range );
	printf( "TF1 integral: %.5f\n", fit_func->Integral( -10, 10 ) );
	TCanvas* canvas = new TCanvas( );
	canvas -> cd( );
	hist_sig5 -> SetMarkerStyle( 21 );
	hist_sig5 -> SetMarkerColor( kBlack );
	hist_sig5 -> SetLineWidth( 1 );
	hist_sig5 -> SetLineColor( kBlack );
	hist_sig5 -> Draw( "ep" );
	hist_sig3 -> SetMarkerStyle( 21 );
	hist_sig3 -> SetMarkerColor( kAzure+2 );
	hist_sig3 -> SetLineWidth( 1 );
	hist_sig3 -> SetLineColor( kAzure+2 );
	hist_sig3 -> Draw( "hist same" );
	fit_func -> SetLineWidth( 2 );
	fit_func -> SetLineColor( kOrange+2 );
	//fit_func -> Draw( "same" );
	fit_func -> Draw( );
	canvas -> SaveAs( "plot_convfit.png" );

	delete roohist_sig5;
	delete roohist_sig3;
	delete roopdf_sig3;
	delete function_range;
	delete g_mean;
	delete g_sigma;
	delete hist_smearing;
	delete conv_pdf;
	delete hist_sig3;
	delete hist_sig5;

	return 0;
}