#include <TROOT.h>
#include <TTree.h>
#include <TH2.h>
#include <TGraphErrors.h>
#include <TFile.h>
#include <TF1.h>
#include <TCanvas.h>

#include <iostream>
#include <fstream>
using namespace std;

#include "tdiff_tgraph.cc"

#include "IsOuter.h"

TGraphErrors* GetPoints(TH2D *h);

//------------------------------------
// Copied from JEventProcessor_bcal_timing.cc
typedef struct{
	int event;
	int layer;
	int sector;
	int fADC_up;
	int fADC_dn;
	float Etot;
	float geometric_mean;
	float tup;
	float tdn;
	float tup_corrected;
	float tdn_corrected;
}HIT_t;
//------------------------------------

//-----------------
// tdiff_calibrate_tgraph
//-----------------
void tdiff_check_tgraph(void)
{

	TFile *f = new TFile("hd_root.root");
	f->cd();
	
	TTree *tree = (TTree*)gROOT->FindObject("tree");
	HIT_t hit;
	HIT_t *hitptr = &hit;
	TBranch *branch = tree->GetBranch("T");
	branch->SetAddress(hitptr);
	
	// Make histograms to hold tdiff vs. geometric mean
	// for each layer.
	TH2D *tdiff_vs_geomn[10+1];
	for(int ilayer=1; ilayer<=10 ; ilayer++){
		char hname[256];
		sprintf(hname, "tdiff_vs_geomn_lay%02d",ilayer);
		tdiff_vs_geomn[ilayer] = new TH2D(hname, "", 2000, 0.0, 4000.0, 100, -5.0, 5.0);
	}

	vector<float> tdiff_correcteds[10+1];
	vector<float> geomns[10+1];
	int Nentries = branch->GetEntries();
	for(int i=1; i<=Nentries; i++){
		tree->GetEntry(i);
		if(hit.layer<1 || hit.layer>10)continue; // bulletproof
		if(hit.tup_corrected<-100)continue;
		if(hit.tdn_corrected<-100)continue;
		float tdiff = hit.tup_corrected - hit.tdn_corrected;
		float geomn = hit.geometric_mean;
		float tdiff_corrected = tdiff - BCAL_tdiff(geomn, hit.layer);
		geomns[hit.layer].push_back(geomn);
		tdiff_correcteds[hit.layer].push_back(tdiff_corrected);
		
		tdiff_vs_geomn[hit.layer]->Fill(geomn, tdiff_corrected);
	}
	
	TCanvas *c1 = new TCanvas("c1");
	c1->SetTicks();
	c1->SetGrid();
	
	TH2D *axes = new TH2D("axes","", 100, 0.0, 3500.0, 100, -15.0, 15.0);
	axes->SetStats(0);
	axes->SetXTitle("fADC");
	axes->SetYTitle("t (ns)");

	// Open PDF file for plots
	c1->Print("tdiff_check_tgraph.ps[");

	// Loop over layers
	int Nlayers=0;
	TF1 *sigma_vs_geomn[10+1];
	for(int ilayer=1; ilayer<=10 ; ilayer++, Nlayers++){

		TGraph *g = new TGraph(geomns[ilayer].size(), &geomns[ilayer][0], &tdiff_correcteds[ilayer][0]);

		char title[256];
		sprintf(title, "#Deltat for layer %d", ilayer);
		axes->SetTitle(title);
		
		TGraphErrors *gres = GetPoints(tdiff_vs_geomn[ilayer]);
		
		axes->Draw();
		g->Draw("Psame");
		gres->Draw("same");

		cout<<"Number of points:"<<g->GetN()<<endl;

		c1->Update();
		c1->Print("tdiff_check_tgraph.ps");
		
		char fname[256];
		sprintf(fname, "tdiff_check_tgraph_layer%02d.png", ilayer);
		c1->SaveAs(fname);
		
		TF1 *fun = gres->GetFunction("fun");
		if(fun){
			char funname[256];
			sprintf(funname, "sigma_vs_geomn_lay%02d", ilayer);
			sigma_vs_geomn[ilayer] = (TF1*)fun->Clone(funname);
		}else{
			sigma_vs_geomn[ilayer] = NULL;
		}
	}
	
	// Close PDF file 
	c1->Print("tdiff_check_tgraph.ps]");
	
	cout<<"Plots written to \"tdiff_check_tgraph.ps\". Convert to PDF with:"<<endl;
	cout<<endl;
	cout<<"  ps2pdf tdiff_check_tgraph.ps"<<endl;
	cout<<endl;
	cout<<"attempting to run for you ...."<<endl;
	system("ps2pdf tdiff_check_tgraph.ps");
	cout<<endl;
	
	// Write resolution functions out as source code
	const char *ofname = "tdiff_res.cc";
	ofstream pout(ofname);
	pout<<"double BCAL_tdiff_res(double geometric_mean, int ilayer)"<<endl;
	pout<<"{"<<endl;
	pout<<"\tdouble &x = geometric_mean;"<<endl;
	pout<<"\tswitch(ilayer){"<<endl;
	string last_expr="1000.0";
	for(int ilayer=1; ilayer<=10; ilayer++){
		pout<<"\t\tcase "<<ilayer<<":"<<endl;
		if(sigma_vs_geomn[ilayer]){
			string expr = (sigma_vs_geomn[ilayer]->GetExpFormula("p")).Data();
			while(true){
				size_t pos=expr.find("(x^");
				if(pos!=string::npos){
					expr.replace(pos, 3, "pow(x,");
				}else{
					break;
				}
			}
			
			// Set resolution to 100ns for outer detectors,
			// effictively disabling them
			if(IsOuter(ilayer))expr = "100.0"; 

			pout<<"\t\t\t"<<"return "<<expr<<";"<<endl;
			pout<<"\t\t\t"<<"break;"<<endl;
			last_expr = expr;
		}
	}
	pout<<"\t\t\t"<<"return "<<last_expr<<";"<<endl;
	pout<<"\t}"<<endl;
	pout<<endl;
	pout<<"\treturn 1000.0;"<<endl;
	pout<<"}"<<endl;
	pout<<endl;
	pout<<endl;
	pout.close();

	cout<<"tdiff resolutions written to \""<<ofname<<"\""<<endl;
	cout<<"Done."<<endl;
}


//------------------
// GetPoints
//------------------
TGraphErrors* GetPoints(TH2D *h)
{
	int min_entries = 300;

	// Project onto the x-axis so we can find the limits for
	// for the projection on the y-axis based on number of events
	TH1D *h_px = h->ProjectionX("_px", 1);

	// Loop over (uneven) bins
	int Npoints = 0;
	vector<double> x;
	vector<double> y;
	vector<double> yerr;
	int Nbins = h->GetNbinsX();
	for(int start_bin=1; start_bin<=Nbins; ){

		// Find limits to give us min_entries entries
		int end_bin = start_bin;
		while(h_px->Integral(start_bin, end_bin)<min_entries && end_bin<Nbins){
			++end_bin;
		}
		
		// If only a few events are left, go ahead and include them here.
		if(end_bin<Nbins && h_px->Integral(end_bin, Nbins)<min_entries)end_bin=Nbins;

		// Project onto y-axis
		cout<<"projecting bins "<<start_bin<<" to "<<end_bin<<"  Nentries="<<h_px->Integral(start_bin, end_bin)<<endl;
		TH1D *h_py = h->ProjectionY("_py",start_bin, end_bin);

		if(h_py->Integral()>=20){
		
			// Fit to Gaussian
			h_py->Fit("gaus","0");
			//c1->Update();

			// Get fit results
			double sigma = h_py->GetFunction("gaus")->GetParameter(2);
			double sigma_err = h_py->GetFunction("gaus")->GetParError(2);

			// Find average fADC value for hits in this bin range
			double fADC = 0.0;
			double norm = 0.0;
			for(int bin=start_bin; bin<=end_bin; bin++){
				double weight = h_px->GetBinContent(bin);
				fADC += h_px->GetBinCenter(bin)*weight;
				norm += weight;
			}
			fADC /= norm;
			
			// Add floor term to error obtained from Gaussian fit
			double epsilon = 0.050; // ns
			sigma_err = sqrt(sigma_err*sigma_err + epsilon*epsilon);

			x.push_back(fADC);
			y.push_back(sigma);
			yerr.push_back(sigma_err);
			Npoints++;
		}

		// Increment for next iteration
		start_bin=end_bin+1;
	}
	
	TGraphErrors *g = new TGraphErrors(Npoints, &x[0], &y[0], 0, &yerr[0]);
	g->SetMarkerColor(kMagenta);
	g->SetLineColor(kMagenta);
	
	// Fit the graph. If there are less than 8 points, just fit to 
	// a flat line.
	TF1 *fun;
	if(Npoints<8){
		fun  = new TF1("fun", "[0]", 0.0, 800.0);
	}else{
		fun = new TF1("fun", "[0] + [1]/(pow(x,[2])+[3])", 0.0, 800.0);
		fun->SetParameter(0, 0.100);
		fun->SetParameter(1, 1000.0);
		fun->SetParameter(2, 1.0);
		fun->SetParameter(3, -3.0);
		
		//fun->SetParLimits(0, 0.0, 3.0);
	}
	
	fun->SetLineColor(kRed);
	g->Fit(fun);

	
	return g;
}