#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <time.h>

#include "alryslib.c"


double round_value(double value, int digits)
{
  int p = pow(10, digits);
  return (int)floor(value * p) / (double)p;
}

double local_search(double *steps, int size, int start, int stop, int digits)
{
  int i, j, k, kmax;
  double v, s, smax, cmax, backup, first, delta;

  smax = score(steps, size);

  for(k = start; k < stop; k += 2)
  {
    steps[k] = round_value(steps[k], digits);
  }

  first = -pow(10, -digits + 1);
  delta = pow(10, -digits);

  for(i = 0; i < 20; ++i)
  {
    kmax = -1;
    cmax = -1.0;
    for(k = start; k < stop; k += 2)
    {
      backup = steps[k];
      for(j = 0; j < 21; ++j)
      {
        v = first + j * delta;

        steps[k] = backup + v;
        s = score(steps, size);
        if(smax < s)
        {
          smax = s;
          kmax = k;
          cmax = backup + v;
        }
      }
      steps[k] = backup;
    }
    if(kmax < 0) break;
    steps[kmax] = cmax;
  }

  return score(steps, size);
}

double random_walk(double *steps, int size, int digits)
{
  int k, l;
  double v, delta;

  delta = pow(10, -digits);

  k = rand() % ((size - 8)/ 4 - 2);
  l = rand() % 11;
  v = (rand() % 3 - 1) * delta * l;
  steps[8 + k * 4] += v;
  v = (rand() % 3 - 1) * delta * l;
  steps[10 + k * 4] += v;
  ++k;
  v = (rand() % 3 - 1) * delta * l;
  steps[8 + k * 4] += v;
  v = (rand() % 3 - 1) * delta * l;
  steps[10 + k * 4] += v;

  return local_search(steps, size, MAX(8 + k * 4 - 8, 8), MIN(size - 4, 8 + k * 4 + 8), digits);
}

int main(int argc, char *argv[])
{
  FILE *fp;
  char *end;
  long digits;
  int size;
  double delta, t, s, sbest, snext, scale;
  double steps[1024], next[1024], best[1024];

  errno = 0;
  digits = (argc == 3) ? strtol(argv[1], &end, 10) : -1;
  if(errno != 0 || end == argv[1] || digits < 2 || digits > 4)
  {
    fprintf(stderr, "Usage: explore [2-4] input_file\n");
    return EXIT_FAILURE;
  }

  if((fp = fopen(argv[2], "r")) == NULL)
  {
    fprintf(stderr, "Cannot open input file.\n");
    return EXIT_FAILURE;
  }

  input(fp, steps, &size);

  srand(time(NULL));

  memcpy(best, steps, size * 8);
  sbest = score(best, size);

  fprintf(stderr, "%f\n", sbest);

  s = sbest;
  t = 1.0;

  scale = pow(10, digits + 3);

  while(t > 0.1)
  {
    t *= 0.999;

    memcpy(next, steps, size * 8);
    snext = random_walk(next, size, digits);

    if(sbest < snext)
    {
      sbest = snext;
      fprintf(stderr, "%f\n", sbest);
      memcpy(best, next, size * 8);
    }

    delta = snext - s;
    if(delta >= 0 || rand() < RAND_MAX * exp(delta / t * scale))
    {
      s = snext;
      memcpy(steps, next, size * 8);
    }
  }

  fprintf(stderr, "-> %f\n", sbest);

  output(best, size);

  return EXIT_SUCCESS;
}