#include <fstream>
#include <iostream>

#include "space_wolff.hpp"
#include <GL/glut.h>

const unsigned D = 2;
typedef Model<double, D, Euclidean<double, D>, double> model;

class animation : public measurement<double, 2, Euclidean<double, D>, double> {
private:
  uint64_t t1;
  uint64_t t2;
  unsigned n;
  unsigned tmp;

public:
  animation(double L, unsigned w, int argc, char* argv[]) {
    t1 = 0;
    t2 = 0;
    n = 0;

    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(w, w);
    glutCreateWindow("wolff");
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(-L, L, -L, L);
  }

  void pre_cluster(const model&, unsigned, const Euclidean<double, D>&) override { tmp = 0; }

  void plain_site_transformed(const model&, const Spin<double, D, double>*,
                              const Spin<double, D, double>&) override {
    tmp++;
  }

  void post_cluster(const model& m) override {
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    for (const Spin<double, 2, double>* s : m.s) {
      glBegin(GL_POLYGON);
      unsigned n_points = 50;
      glColor3f(0.0f, 0.0f, 0.0f);
      for (unsigned i = 0; i < n_points; i++) {
        glVertex2d(m.s0.inverse().act(*s).x(0) + s->s * cos(2 * i * M_PI / n_points),
                   m.s0.inverse().act(*s).x(1) + s->s * sin(2 * i * M_PI / n_points));
      }
      glEnd();
    }
    glFlush();

    t1 += tmp;
    t2 += tmp * tmp;
    n++;
  }

  void clear() {
    t1 = 0;
    t2 = 0;
    n = 0;
  }

  double var() { return (t2 - t1 * t1 / (double)n) / (double)n; }
};

Gen<double, D, Euclidean<double, D>, double> eGen(double ε) {
  return [ε](model& M, Rng& rng) -> Transformation<double, D, Euclidean<double, D>, double>* {
    Vector<double, D> t;
    Matrix<double, D> m;

    double θ = rng.uniform((double)0.0, 2 * M_PI);
    m(0, 0) = -cos(2 * θ);
    m(1, 1) = cos(2 * θ);
    m(0, 1) = -2 * cos(θ) * sin(θ);
    m(1, 0) = -2 * cos(θ) * sin(θ);

    Spin<double, D, double>* s = rng.pick(M.s);
    t = s->x;
    for (unsigned j = 0; j < D; j++) {
      t(j) += rng.variate<double, std::normal_distribution>(0.0, ε);
    }

    Euclidean<double, D> g(t - m * t, m);
    return new SpinFlip<double, D, Euclidean<double, D>, double>(M, g, s);
  };
}

Gen<double, D, Euclidean<double, D>, double> mGen(double ε) {
  return [ε](model& M, Rng& rng) -> Transformation<double, D, Euclidean<double, D>, double>* {
    Matrix<double, D> m;

    Spin<double, D, double>* s1 = rng.pick(M.s);
    Spin<double, D, double>* s2 = rng.pick(M.s);

    while (s1 == s2) {
      s2 = rng.pick(M.s);
    }

    Vector<double, D> t1 = s1->x;
    Vector<double, D> t2 = s2->x;
    Vector<double, D> t12 = t1 - t2;
    Vector<double, D> t = (t1 + t2) / 2;

    double θ = atan2(t12[1], t12[0]) + rng.variate<double, std::normal_distribution>(0.0, ε);

    m(0, 0) = -cos(2 * θ);
    m(1, 1) = cos(2 * θ);
    m(0, 1) = -2 * cos(θ) * sin(θ);
    m(1, 0) = -2 * cos(θ) * sin(θ);

    Euclidean<double, D> g(t - m * t, m);
    return new PairFlip<double, D, Euclidean<double, D>, double>(M, g, s1, s2);
  };
}

Gen<double, D, Euclidean<double, D>, double> rGen(double ε) {
  return [ε](model& M, Rng& rng) -> Transformation<double, D, Euclidean<double, D>, double>* {
    Vector<double, D> t;
    Matrix<double, D> m;

    double θ = rng.uniform((double)0.0, 2 * M_PI);
    m(0, 0) = -cos(2 * θ);
    m(1, 1) = cos(2 * θ);
    m(0, 1) = -2 * cos(θ) * sin(θ);
    m(1, 0) = -2 * cos(θ) * sin(θ);

    Spin<double, D, double>* s = rng.pick(M.s);
    t = M.s0.t;
    for (unsigned j = 0; j < D; j++) {
      t(j) += rng.variate<double, std::normal_distribution>(0.0, ε);
    }

    Euclidean<double, D> g(t - m * t, m);
    return new SpinFlip<double, D, Euclidean<double, D>, double>(M, g, s);
  };
}

int main(int argc, char* argv[]) {
  const unsigned D = 2;

  double L = 32;
  unsigned N = 1000;
  double T = 2.0 / log(1.0 + sqrt(2.0));
  double H = 1.0;
  unsigned n = 25;

  double k = 1e2;
  double a = 0.1;

  int opt;

  while ((opt = getopt(argc, argv, "n:N:L:T:H:a:k:")) != -1) {
    switch (opt) {
    case 'n':
      n = (unsigned)atof(optarg);
      break;
    case 'N':
      N = (unsigned)atof(optarg);
      break;
    case 'L':
      L = atof(optarg);
      break;
    case 'T':
      T = atof(optarg);
      break;
    case 'H':
      H = atof(optarg);
      break;
    case 'a':
      a = atof(optarg);
      break;
    case 'k':
      k = atof(optarg);
      break;
    default:
      exit(1);
    }
  }

  std::function<double(const Spin<double, D, double>&, const Spin<double, D, double>&)> Z =
      [L, a, k](const Spin<double, D, double>& s1, const Spin<double, D, double>& s2) -> double {
    Vector<double, D> d = s1.x - s2.x;

    double σ = s1.s + s2.s;
    double δ = σ - sqrt(d.transpose() * d);

    if (δ > -a * σ) {
      return 0.5 * k * (2 * pow(a * σ, 2) - pow(δ, 2));
    } else if (δ > -2 * a * σ) {
      return 0.5 * k * pow(δ + 2 * a * σ, 2);
    } else {
      return 0;
    }
  };

  std::function<double(Spin<double, D, double>)> B = [L, H](Spin<double, D, double> s) -> double {
    return H * s.x.norm();
  };

  auto g1 = eGen(2);
  auto g2 = mGen(0.5);
  auto g3 = rGen(5);
  animation A(L, 750, argc, argv);
  model sphere(1.0, Z, B);

  Rng rng;

  sphere.s.resize(n);

  unsigned nx = floor(sqrt(n));
  for (unsigned i = 0; i < sphere.s.size(); i++) {
    Spin<double, 2, double>* ss = new Spin<double, 2, double>();
    ss->x = {(i / nx) * L / nx, (i % nx) * L / nx};
    ss->s = rng.uniform<double>(0.45, 0.45);
    sphere.s[i] = ss;
    sphere.dict.insert(ss);
  }

  sphere.wolff(T, {g1, g2, g3}, A, N);
  std::ofstream outfile;
  outfile.open("test.dat");

  /*
  for (signed i = -10; i <= 10; i++) {
    A.clear();
    double ε = pow(2, -4 + i / 2.0);
    auto gn = eGen(ε);
    sphere.wolff(T, gn, A, N);
    outfile << ε << " " << A.var() / sphere.s.size() << std::endl;
    std::cout << ε << " " << A.var() / sphere.s.size() << std::endl;
  }
  */

  outfile.close();

  std::ofstream snapfile;
  snapfile.open("sphere_snap.dat");

  for (Spin<double, D, double>* s : sphere.s) {
    Spin<double, D, double> rs = sphere.s0.inverse().act(*s);
    snapfile << rs.x.transpose() << "\n";
    delete s;
  }

  snapfile.close();

  return 0;
}