#include <helianthus.h></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();

}