#ifndef SIM_HPP
#define SIM_HPP

#include <gsl/gsl_rng.h>
#include <complex>
#include <math.h>

#include "latlib/neigh.h"

#define EPSILONPHI 0.5

class sim : public o815::sim {
public:
  struct siteconf {
    complex<double> phi;
  };
  sim(o815 *_O815);
  siteconf* conf;
  unsigned int LSIZE2;
  double M;
  double m;
  neigh *nb;

private:
  void _makeSweep();
  void _newParas();
  gsl_rng* rangsl;
  int updatePhi (const int& x);
  double SofPhi(const int& x, const complex<double>& phix);
  double rhoPhi(const int& x, const complex<double>& phixCandidate);
};



sim::sim(o815 *_O815) : o815::sim( _O815, 
				   sizeof(siteconf)*
				   (_O815->comargs.lsize[0]*_O815->comargs.lsize[1]) ) {
  conf = (siteconf*)confMem;

  rangsl = gsl_rng_alloc(gsl_rng_ranlxs0);
  gsl_rng_set(rangsl, time(NULL));

  LSIZE2 = _O815->comargs.lsize[0] * _O815->comargs.lsize[1];

  nb = new neigh(2, _O815->comargs.lsize[0], _O815->comargs.lsize[1]);
}

void sim::_makeSweep() {  
  for (int ichecker=0; ichecker<2; ichecker++)
    for (int it=0; it<O815->comargs.lsize[0]; it++)
      for (int iy=(it+ichecker)%2; iy<O815->comargs.lsize[1]; iy+=2)
	updatePhi( it*O815->comargs.lsize[1] + iy );
}

void sim::_newParas() {
  m = (*O815->paraQ)["mass"];
  M = pow( (*O815->paraQ)["mass"], 2 ) + 4;
  *log << "SIM: Resetting fields." << endl << flush;

  for (int ix=0; ix<LSIZE2; ix++)
    conf[ix].phi = polar( 1., gsl_rng_uniform(rangsl) * 2*M_PI );
}

int sim::updatePhi(const int& x) {
  complex<double> phixCandidate = conf[x].phi +
    complex<double> ( 2*EPSILONPHI*( 0.5 - gsl_rng_uniform(rangsl) ), 
		      2*EPSILONPHI*( 0.5 - gsl_rng_uniform(rangsl) ) );
  
  if ( gsl_rng_uniform(rangsl) < rhoPhi(x, phixCandidate) ) {
    conf[x].phi = phixCandidate;
    return 1;
  }
  
  return 0;
}

double sim::rhoPhi(const int& x, const complex<double>& phixCandidate) {
  return exp( SofPhi(x, conf[x].phi) - SofPhi(x, phixCandidate) );
}

double sim::SofPhi(const int& x, const complex<double>& phix) {
  double sofphi = M * norm(phix);
  
  for (int nu=0; nu<4; nu++)
    sofphi -= 2 * real( conj(phix) * conf[ (*nb)[x*4+nu] ].phi );
  
  return sofphi;
}

#endif