#include <string>
#include <iostream>
#include <iomanip>

#include "TROOT.h"
#include "TFile.h"
#include "TH2D.h"
#include "TMath.h"
#include "TRandom.h"

#include "JTools/JHistogram1D_t.hh"
#include "JTools/JHistogramMap_t.hh"
#include "JTools/JMultiHistogram.hh"
#include "JTools/JCollection.hh"
#include "JTools/JMultiGrid.hh"
#include "JTools/JMultiSet.hh"
#include "JTools/JQuadrature.hh"
#include "JTools/JFunction1D_t.hh"
#include "JTools/JFunctionalMap_t.hh"
#include "JTools/JToolsToolkit.hh"
#include "JTools/JMultiPDF.hh"

#include "Jeep/JParser.hh"
#include "Jeep/JMessage.hh"


namespace {
  /**
   * Function g1.
   *
   * \param  x       x value
   * \return         function value
   */
  inline Double_t g1(const Double_t x)
  {
    return TMath::Gaus(x, 0.0, 1.0, kTRUE);
  }
  
  
  /**
   * Integral of g1.
   *
   * \param  x       x value
   * \return         integral value
   */
  inline Double_t G1(const Double_t x)
  {
    return 0.5 * (1.0 + TMath::Erf(sqrt(0.5)*x));
  }

  /**
   * Function g2.
   *
   * \param  x       x value
   * \param  y       y value
   * \return         function value
   */
  inline Double_t g2(const Double_t x, const Double_t y)
  {
    return g1(x) * g1(y);
  }
  
  
  /**
   * Integral of g2.
   *
   * \param  x       x value
   * \param  y       y value
   * \return         integral value
   */
  inline Double_t G2(const Double_t x, const Double_t y)
  {
    return G1(x) * G1(y);
  }
}


/**
 * \file
 *
 * Example program to test JTOOLS::JMultiHistogram.
 * \author mdejong
 */
int main(int argc, char **argv)
{
  using namespace std;

  string  outputFile;
  int     numberOfEvents;
  int     numberOfBins;
  bool    quadrature;
  bool    subtract;
  int     debug;

  try {

    JParser<> zap("Example program to test 2D histogram.");

    zap['o'] = make_field(outputFile)     = "histogram.root";
    zap['n'] = make_field(numberOfEvents);
    zap['N'] = make_field(numberOfBins);
    zap['Q'] = make_field(quadrature);
    zap['D'] = make_field(subtract);
    zap['d'] = make_field(debug)          = 3;

    zap(argc, argv);
  }
  catch(const exception &error) {
    FATAL(error.what() << endl);
  }


  if (numberOfEvents <= 0) {
    FATAL("No events." << endl);
  }

  using namespace JPP;

  const Int_t    nx    =  100;
  const Double_t xmin  = -3.0;
  const Double_t xmax  = +3.0;

  typedef JMultiHistogram<JHistogram1D_t,
			  JMapList<JHistogramMap_t> >  JHistogram2D_t;

  JHistogram2D_t histogram;
  

  // abscissa

  if (!quadrature)
    configure(histogram, make_grid(numberOfBins + 1, xmin, xmax));
  else
    configure(histogram, make_set(JGaussHermite(numberOfBins + 1)));

  
  // fill

  for (int i = 0; i != numberOfEvents; ++i) {

    const double x = gRandom->Gaus(0.0, 1.0);
    const double y = gRandom->Gaus(0.0, 1.0);

    histogram.fill(x, y, 1.0);
  }
  
  
  histogram.div((double) numberOfEvents);

  
  // interpolation based on function values

  JMultiPDF<JPolint2Function1D_t,
	    JMapList<JPolint2FunctionalMap> >         f2(histogram);


  // interpolation based on integral values

  accumulate(histogram);
  
  JMultiFunction<JPolint3Function1H_t,
		 JMapList<JPolint3FunctionalMapH> >   F2;

  copy(histogram, F2);

  F2.compile();


  TFile out(outputFile.c_str(), "recreate");

  TH2D h0("h0", NULL, nx, xmin, xmax, nx, xmin, xmax);
  TH2D h1("h1", NULL, nx, xmin, xmax, nx, xmin, xmax);
  TH2D h2("h2", NULL, nx, xmin, xmax, nx, xmin, xmax);

  
  for (int i = 1; i <= h0.GetXaxis()->GetNbins(); ++i) {
    for (int j = 1; j <= h0.GetYaxis()->GetNbins(); ++j) {
      
      const Double_t x = h0.GetXaxis()->GetBinCenter(i);
      const Double_t y = h0.GetYaxis()->GetBinCenter(j);
      
      h0.SetBinContent(i, j, g2(x,y));
      
      try {
	h1.SetBinContent(i, j, F2(x,y).fp.fp);
	h2.SetBinContent(i, j, f2(x,y));
      }
      catch(const exception& error) {
	//ERROR(error.what() << endl);
      }
    }
  }

  if (subtract) {
    h1.Add(&h0, -1.0);
    h2.Add(&h0, -1.0);
  }

  out.Write();
  out.Close();
}