#include <iostream>
#include <utility>
#include <array>
#include <memory>
#include "TRandom3.h"
#include "TStyle.h"
#include "TH1D.h"
#include "TCanvas.h"
#include "TPad.h"

template<typename T, typename... Args>
std::unique_ptr<T> make_unique(Args&&... args) {
    return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
}

std::unique_ptr<TH1D> genHisto(int idx) {
  static TRandom3 r;
  char name[8]; sprintf(name,"histo_%d",idx);
  std::unique_ptr<TH1D> histo = make_unique<TH1D>(name,"",100,-5,5);
  for (int i = 0; i < 1000; ++i)
    histo->Fill(r.Gaus());
  return histo;
}

std::pair< std::unique_ptr<TPad>,std::unique_ptr<TPad> > makeSubpads(int idx) {
  const double pad = 0.07;
  const double frac = 0.2;
  const double gap = 0.01;
  char tname[12]; sprintf(tname,"histo_%d_pad",idx);
  char bname[12]; sprintf(bname,"ratio_%d_pad",idx);
  std::unique_ptr<TPad> padT = make_unique<TPad>(tname, tname, 0.0,pad+frac+gap,1.0,1.0);
  std::unique_ptr<TPad> padB = make_unique<TPad>(bname, bname, 0.0,pad,1.0,frac+pad);
  return { std::move(padT), std::move(padB) };
}

void jwimberl () {

  // STYLE
  const double width = 800;
  const double height = 500;

  gStyle->SetOptStat(0);
  const int font = 133;
  gStyle->SetTextFont(font);
  gStyle->SetLabelFont(font,"x");
  gStyle->SetLabelFont(font,"y");
  gStyle->SetTitleFont(font);
  gStyle->SetTitleFont(font,"x");
  gStyle->SetTitleFont(font,"y");
  const double size = 20;
  gStyle->SetTextSize(size);
  gStyle->SetLabelSize(size,"x");
  gStyle->SetLabelSize(size,"y");
  gStyle->SetTitleSize(1.2*size,"x");
  gStyle->SetTitleSize(1.2*size,"y");

  // DATA
  const int N = 2;
  std::unique_ptr<TH1D> nomHisto = genHisto(0);
  std::array<std::unique_ptr<TH1D>,N> histos;
  std::array<std::unique_ptr<TH1D>,N> ratios;
  for (int i = 0 ; i < N; ++i) {
    histos[i] = genHisto(i+1);
    ratios[i] = std::unique_ptr<TH1D>(static_cast<TH1D*>(histos[i]->Clone()));
    ratios[i]->Divide(nomHisto.get());

    ratios[i]->GetYaxis()->SetNdivisions(603);
    ratios[i]->SetMinimum(0.0);
    ratios[i]->SetMinimum(3.0);
    ratios[i]->GetXaxis()->SetTitleOffset(12.0);
    ratios[i]->GetXaxis()->SetTitle("TEST LABEL");
  }

  // SIMPLE PLOT
  TCanvas csimple("csimple","csimple",width,height*N);
  csimple.Divide(1,N);
  for (int i = 0 ; i < N; ++i) {
    csimple.cd(i+1);
    histos[i]->Draw();
  }
  csimple.Print("csimple.png");
  csimple.Print("csimple.pdf");

  // COMPLEX PLOT
  TCanvas ccomplex("ccomplex","ccomplex",width,height*N);
  ccomplex.SetFillStyle(4000);
  ccomplex.Divide(1,N);
  std::array<std::pair<std::unique_ptr<TPad>,std::unique_ptr<TPad>>,N> pads;
  for (int i = 0 ; i < N; ++i) {
    ccomplex.cd(i+1);
    pads[i] = makeSubpads(i);
    pads[i].first->Draw();
    pads[i].second->Draw();
    pads[i].first->cd();
    histos[i]->Draw();
    pads[i].second->cd();
    ratios[i]->Draw();
  }
  ccomplex.Print("ccomplex.png");
  ccomplex.Print("ccomplex.pdf");
}