#include <fstream>
#include <getopt.h>

#include "randutils/randutils.hpp"

#define WOLFF_USE_FINITE_STATES
#include "wolff/lib/wolff_models/ising.hpp"

using namespace wolff;

class sample : public measurement<ising_t, ising_t, graph<>> {
private:
  typedef struct _dat {
    int e;
    int m;
  } dat;
  std::ofstream e_file;
  dat e;

public:
  sample(const wolff::system<ising_t, ising_t, graph<>>& s, unsigned D, unsigned L, double T,
         double H) {
    e_file.open("sample_" + std::to_string(D) + "_" + std::to_string(L) + "_" + std::to_string(T) +
                    "_" + std::to_string(H) + ".bin",
                std::ios::out | std::ios::binary | std::ios::app);
    e.e = -s.ne;
    e.m = s.nv;
  }

  ~sample() { e_file.close(); }

  void ghost_bond_visited(const system<ising_t, ising_t, graph<>>&, const typename graph<>::vertex&,
                          const ising_t& s_old, const ising_t& s_new, double dE) override {
    e.m += s_new - s_old;
  }

  void plain_bond_visited(const wolff::system<ising_t, ising_t, graph<>>& s,
                          const typename graph<>::halfedge& ed, const ising_t& si_new,
                          double dE) override {
    e.e -= 2 * (si_new * s.s[ed.neighbor.ind]);
  }

  void post_cluster(unsigned n, unsigned,
                    const wolff::system<ising_t, ising_t, graph<>>&) override {
    e_file.write((char*)&e, 2 * sizeof(int));
  }
};

int main(int argc, char* argv[]) {

  // set defaults
  unsigned N = (unsigned)1e4;
  unsigned D = 2;
  unsigned L = 128;
  double T = 2 / log(1 + sqrt(2));
  double H = 0;

  int opt;

  // take command line arguments
  while ((opt = getopt(argc, argv, "N:D:L:T:H:")) != -1) {
    switch (opt) {
    case 'N': // number of steps
      N = (unsigned)atof(optarg);
      break;
    case 'D': // dimension
      D = atoi(optarg);
      break;
    case 'L': // linear size
      L = atoi(optarg);
      break;
    case 'T': // temperature
      T = atof(optarg);
      break;
    case 'H': // field
      H = atof(optarg);
      break;
    default:
      exit(EXIT_FAILURE);
    }
  }

  // define the spin-spin coupling
  std::function<double(const ising_t&, const ising_t&)> Z =
      [](const ising_t& s1, const ising_t& s2) -> double { return (double)(s1 * s2); };

  // define the spin-field coupling
  std::function<double(const ising_t&)> B = [=](const ising_t& s) -> double { return H * s; };

  // initialize the lattice
  graph<> G(D, L);

  // initialize the system
  wolff::system<ising_t, ising_t, graph<>> S(G, T, Z, B);

  // initialize the random number generator
  randutils::auto_seed_128 seeds;
  std::mt19937 rng{seeds};

  // define function that generates self-inverse rotations
  std::function<ising_t(std::mt19937&, const wolff::system<ising_t, ising_t, graph<>>&,
                        const graph<>::vertex&)>
      gen_r = gen_ising<graph<>>;

  // initailze the measurement object
  sample A(S, D, L, T, H);

  // run wolff N times
  S.run_wolff(N, gen_r, A, rng);

  // exit
  return 0;
}