// Draw Longitudinal Shower Profile

#include "TH1D.h"
#include "TFile.h"
#include "THStack.h"
#include "TCanvas.h"
#include "TString.h"
#include "TLegend.h"

TCanvas* cmpE()
{
  // TString dataDir("/net/llrdata1.in2p3.fr/data/DATA/data.harpo/BH5D/");
  TString dataDir("./");

  TString dataFile[2];
  dataFile[0] = "gflash00.root";
  dataFile[1] = "gflash01.root";

  TFile* f[2];
  TH1D*  p[2];
  //  UInt_t col[] = { kRed, kBlue, kGreen, kViolet };
  UInt_t col[] = {kRed, kGreen, kBlue, kViolet};
  //  UInt_t mark[] = { 20, 32, 21, 22};
  UInt_t mark[] = {20, 21, 32, 22};
  //
  THStack* hs = new THStack("hs", "");

  for ( UInt_t i = 0; i < 2; i++ ) {
    TString tmp = dataDir + dataFile[i];
    f[i]        = TFile::Open(tmp);
    if ( ! f[i] ) return 0;
    p[i] = (TH1D*)(f[i])->Get("h0");
    // ShiftUp(p[i],0.0);
    // histogram
    p[i]->SetFillColor(col[i]);
    p[i]->SetLineStyle(i + 2);
    p[i]->SetLineColor(col[i]);
    p[i]->SetLineWidth(2);
    p[i]->SetMarkerStyle(mark[i]);
    p[i]->SetMarkerColor(col[i]);
    p[i]->SetMarkerSize(1.5);
    hs->Add(p[i]);
  }
  TCanvas* cst = new TCanvas("cst", "stacked hists", 10, 10, 800, 700);
  // gPad->SetGrid();
  hs->Draw("p,nostack");
  hs->SetTitle("Total Energy");
  hs->GetXaxis()->SetTitle("E/E_{tot} (%)");
  //  hs->GetYaxis()->SetTitle("No of events");

  cst->RedrawAxis();
  cst->Update();

  TLegend* legend = new TLegend(0.65, 0.84, 0.94, 0.94);
   legend->AddEntry(p[0],
     Form("full  - E %5.3f #sigma %5.3f",p[0]->GetMean(),p[0]->GetRMS()),"p");
  legend->AddEntry(p[1],
     Form("gflash - E %5.3f #sigma %5.3f",p[1]->GetMean(),p[1]->GetRMS()),"p");
  legend->Draw();
  cst->Update();

  // img->FromPad(c, 10, 10, 300, 200);

  // TImage *img = TImage::Create();

  // img->FromPad(cst);

  // img->WriteImage("hist0-640MeV-p.png");

  // for (UInt_t i = 0; i < 4; i++) {
  // f[i]->Close();
  // }
  return cst;
}