#include <iostream>
#include <cstdlib>
#include <memory>

#include "AIDA_Proxy/AIDA_Proxy.h"

// Class declarations from CLHEP
#include "CLHEP/Random/RandGauss.h"
#include "CLHEP/Random/DRand48Engine.h"

#include <sstream>

int main( int, char** )
{

  // Creating a histogram
  pi_aida::Histogram1D h1("Gaussian Distribution", 100, 0, 100);

  // Filling the histogram with random data following a gaussian distribution
  DRand48Engine randomEngine;
  RandGauss rgauss( randomEngine, 45, 10 );
  for ( int i = 0; i < 10000; ++i ) {
    h1.fill( rgauss.fire() );
  }

  std::cout << "Histogram :" << std::endl;
  std::cout << "  Title : " << h1.title() << std::endl;
  std::cout << "  Entries : " << h1.entries() << std::endl;
  std::cout << "  Mean : " << h1.mean() << std::endl;
  std::cout << "  Rms : " << h1.rms() << std::endl;

  // Creating the function which is going to be fitted with the histogram data
  pi_aida::Function gaussFun("G");

  // set function initial parameters
  gaussFun.setParameter("mean" , 50.);
  gaussFun.setParameter("sigma", 10.);
  gaussFun.setParameter("amp"  , 50.);

  // Creating the fitter using lcg_minit
  pi_aida::Fitter fitter("Chi2","lcg_minuit");
  // Creating the fitter using old fortran minit
  //pi_aida::Fitter fitter("Chi2","minuit");

  // Performing the fit
  AIDA::IFitResult*  fitResult =  fitter.fit( h1, gaussFun );

  // check fit 
  if (fitResult) { 

    // Printing the fit results
    std::cout << "Fit result : chi2 / ndf : " << fitResult->quality() << " / " << fitResult->ndf() << std::endl;
    const std::vector<std::string>& parNames = fitResult->fittedParameterNames();
    const std::vector<double>& par = fitResult->fittedParameters();
    const std::vector<double>& epar = fitResult->errors();

    for ( unsigned int i = 0; i < par.size(); ++i ) {
      std::cout << parNames[i] << " = " << par[i] << " +/- " << epar[i] << std::endl;
    }

    // Add in the annotation of the histogram the fit result
    AIDA::IAnnotation& annotation = h1.annotation();
    for ( unsigned int i = 0; i < par.size(); ++i ) {
      std::ostringstream os;
      os << par[i] << " +/- " << epar[i];
      annotation.addItem( parNames[i], os.str() );
    }

    // Remove some existing annotation items
    annotation.removeItem( "Overflow" );
    annotation.removeItem( "Underflow" );
    annotation.removeItem( "Extra Entries" );
  }
  else { 
    std::cout << "\n>>>Error:    Fit failed ! " << std::endl; 
    return 1; 
  }

  return 0;
}