#include <helianthus.h>


#define ROWS 12
#define COLS 18


int map[ROWS][COLS][3];


int visit(int r, int c) {
  if (r < 0 || c < 0 || r >= ROWS || c >= COLS) return FALSE;

  if (map[r][c][2]) return randomFloat()*100 < 2;
  map[r][c][2] = TRUE;

  int ways[4] = {0, 1, 2, 3};
  for(int i = 0; i < 4; ++i) {
    int a = randomNumber(0, 3);
    int b = randomNumber(0, 3);
    int n = ways[a];
    ways[a] = ways[b];
    ways[b] = n;
  }

  for(int i = 0; i < 4; ++i) {
    switch(ways[i]) {
    case 0:
      if (visit(r, c-1)) map[r  ][c  ][0] = TRUE;
      break;
    case 1:
      if (visit(r, c+1)) map[r  ][c+1][0] = TRUE;
      break;
    case 2:
      if (visit(r-1, c)) map[r  ][c  ][1] = TRUE;
      break;
    case 3:
      if (visit(r+1, c)) map[r+1][c  ][1] = TRUE;
      break;
    }
  }

  return TRUE;
}


void generate() {
  for(int r = 0; r < ROWS; ++r)
    for(int c = 0; c < COLS; ++c)
      for(int i = 0; i < 3; ++i)
        map[r][c][i] = 0;
  visit(0, 0);
}



void init() {
  generate();
}


void draw() {
  double w = windowGetWidth();
  double h = windowGetHeight();

  if (keyWentDown("space")) generate();

  saveState();
  translate(w/2, h/2);
  zoom(w/(COLS + 1));
  translate(-COLS/2.0, -ROWS/2.0);

  strokeWidth(0.1);
  for(int r = 0; r < ROWS; ++r) {
    for(int c = 0; c < COLS; ++c) {
      if (!map[r][c][0]) line(c, r, c, r+1);
      if (!map[r][c][1]) line(c, r, c+1, r);
    }
  }
  line(COLS, 0, COLS, ROWS);
  line(0, ROWS, COLS, ROWS);

  restoreState();
}


int main() {
  windowSetVariableFrameRate();
  windowSetResizable(TRUE);
  windowSetInit(&init);
  windowSetDraw(&draw);
  windowRun();
}