#include <stdio.h>
#include <iostream>


//===============================
// * EGamma crystal ball function
//===============================
double Func_EGMCrystalBall (double *x,  double *par)
{
	double funcVal=0;
	
	
	// + List of parameters
	//---------------------
	double  sigmaLeft  = 2.776;
	double  sigmaRight = 2.0;
	double  mean       = 90.0-2.178;
	double  alpha      = 1.791;
	double  tailLeft   = 1.0;
	double  slope      = -0.303;
	
	// + List of variables
	//--------------------
	double  zLeft  = (x[0] - mean) / sigmaLeft;
	double  zRight = (x[0] - mean) / sigmaRight;
	
	
	if (tailLeft >= 0 )
	{
		if (zLeft > 0)
		{
			funcVal = exp (-0.5*zRight*zRight);
		}
		else
		{
			if (zLeft > -alpha)
			{
				funcVal = exp(-0.5*zLeft*zLeft);
			}
			else
			{
				double a = exp (-0.5*alpha*alpha);
				double b = exp (slope * (zLeft+alpha));
				
				funcVal = a * b;
			}
		}
	}
	else
	{
		//// rather fit high tail for n < 0
		if (zRight < 0)
		{
			funcVal= exp (-0.5*zLeft*zLeft);
		}
		else if (zRight < alpha)
		{
			funcVal= exp(-0.5*zRight*zRight);
		}
		else
		{
			double a = pow(slope/alpha, slope) * exp(-0.5*alpha*alpha);
			double b = slope/alpha - alpha;
			funcVal= a/pow(b+zRight, slope);
		}
	}
	
	return 100*funcVal;
}






// + Charaterize function
//=======================
// * Style functions
void Characterize_Function (TF1 *func, int colour_func)
{
	func -> SetTitle                     ("");
	func -> GetXaxis() -> SetTitle       ("M(ee) [GeV]");
	func -> GetXaxis() -> SetTitleSize   (0.035);
	func -> GetXaxis() -> SetTitleOffset (1.6);
	func -> GetXaxis() -> SetLabelSize   (0.025);
	func -> GetXaxis() -> SetLabelOffset (0.03);
	func -> GetXaxis() -> SetNdivisions  (10, 0);
	func -> GetYaxis() -> SetTitle       ("Number of events");
	func -> GetYaxis() -> SetTitleSize   (0.035);
	func -> GetYaxis() -> SetLabelSize   (0.025);
	func -> GetYaxis() -> SetTitleOffset (1.2);
	func -> SetLineWidth   (2);
	func -> SetLineColor   (colour_func);
	func -> SetMarkerColor (colour_func);
	func -> SetMarkerStyle (20);
	func -> SetMarkerSize  (1);
}






//================
// * Main function
//================
void CodeTest_EGMCrystalBall ()
{
	system ("mkdir -p /home/longhoa/ROOT_Work/Task_Test/Output/Plot_TestFunction/");
	
	gStyle -> SetOptStat (0);
	gStyle -> SetOptFit  (0);
	
	
	// + Define the function to be drawn
	//----------------------------------
	// * Draw function
	TF1 *func_draw = new TF1("func_draw", Func_EGMCrystalBall, 60, 120, 0);
	
	
	// + Charaterize the objects
	//--------------------------
	// * Function
	//func_draw -> SetLineWidth  (2);
	//func_draw -> SetLineColor  (kAzure);
	Characterize_Function (func_draw, (int)kAzure);
	
	
	// + Draw everything onto a canvas
	//--------------------------------
	// * Canvas
	TCanvas *canvas = new TCanvas (Form("canvas1"), "", 600, 600);
	canvas -> cd ();
	// * Pad
	TPad *pad = new TPad (Form("pad1"), "", 0.0, 0.0, 1.0, 1.0);
	pad -> SetTopMargin    (0.050);
	pad -> SetBottomMargin (0.120);
	pad -> SetLeftMargin   (0.120);
	pad -> SetRightMargin  (0.050);
	pad -> SetGrid         (1, 1);
	pad -> Draw ();
	pad -> cd();
	// * Draw main stuff
	func_draw -> Draw ();
	// * Draw legend
	TLegend *legend = new TLegend (0.320, 0.870, 0.750, 0.920);
	legend -> SetTextSize (0.030);
	//legend -> SetNColumns (3);
	//legend -> AddEntry (func,     "Data", "ep");
	//legend -> AddEntry (func_fit, "Fit",  "l");
	legend -> AddEntry (func_draw, "Egamma Crystal Ball",  "l");
	legend -> Draw ("same");
	// * Draw title
	//TLatex *tex1 = new TLatex();
	//tex1 -> SetNDC      ();
	//tex1 -> SetTextFont (42);
	//tex1 -> SetTextSize (0.032);
	//tex1 -> DrawLatex   (0.075, 0.940, Form("Signal: Landau x Gaussian (#bf{%ld})", nSignal));
	// * Print information
	TLatex *tex11 = new TLatex();
	tex11 -> SetNDC       ();
	tex11 -> SetTextFont (42);
	tex11 -> SetTextSize  (0.028);
	tex11 -> SetTextAlign (13);
	//tex11 -> DrawLatex (0.770, 0.800, Form("#bf{Fit parameters - Signal}"));
	//tex11 -> DrawLatex (0.770, 0.750, Form("#bullet Width = %.2f (#color[%d]{5} ) #pm %.2f", width_v, kAzure, width_e));
	//tex11 -> DrawLatex (0.770, 0.700, Form("#bullet MIP = %.2f (#color[%d]{40} ) #pm %.2f", mip_v, kAzure, mip_e));
	//tex11 -> DrawLatex (0.770, 0.650, Form("#bullet Area = %.0f (#color[%d]{%ld} ) #pm %.0f", area1_v, kAzure, nSignal, area1_e));
	//tex11 -> DrawLatex (0.770, 0.600, Form("#bullet sigma = %.2f (#color[%d]{4} ) #pm %.2f", gsig1_v, kAzure, gsig1_e));
	//tex11 -> DrawLatex (0.770, 0.500, Form("#bf{Fit quality}"));
	//tex11 -> DrawLatex (0.770, 0.450, Form("#bullet #chi^{2}/ndf = %.1f/%d = %.2f", chi1, ndf1, con1));
	
	
	// + Save to file
	//---------------
	canvas -> SaveAs (Form("/home/longhoa/ROOT_Work/Task_Test/Output/Plot_TestFunction/function_EGammaCrystalBall.png"));
	
}