import "libc.hff";

def W = 60, H = 40;

typedef Board [(W * H)/8]u8;
static board Board = {};

fn get(b *Board, x uint, y uint) bool {
   x %= W; y %= H;
   let idx = x + (y * W);
   return b.[idx / 8] & (1 << (idx % 8)) != 0;
}

fn set(b *Board, x uint, y uint, set bool) void {
   x %= W; y %= H;
   let idx = x + (y * W);
   b.[idx / 8] &= ~(1 << (idx % 8));
   if set {
      b.[idx / 8] |= (1 << (idx % 8));
   }
}

fn next(b *Board) void {
   let temp Board = *b;
   for let y = 0; y < H; ++y {
      for let x = 0; x < W; ++x {
         defmacro C(ox,oy) [ (as(int)get(&temp, x + ox, y + oy)) ]
         let n = C(-1,-1) + C(0,-1) + C(1,-1)
               + C(-1, 0)      +      C(1, 0)
               + C(-1, 1) + C(0, 1) + C(1, 1);

         set(b, x, y, get(&temp, x, y) ? n == 3 : n == 2 or n == 3);
      }
   }
}

fn draw(b *Board) void {
   printf("\x1B[H\n");
   printf("\n");
   for let y = 0; y < H; ++y {
      printf(" ");
      for let x = 0; x < W; ++x {
         if get(b, x, y) {
            printf("W");
         } else {
            printf(" ");
         }
      }
      printf(" \n");
   }
}

extern fn time(*void) int;
fn init(b *Board) void {
   let rnd u32 = time(#null);
   for let y = 0; y < H; ++y {
      for let x = 0; x < W; ++x {
         set(b, x, y, as(bool)((rnd >> 31) & 1));
         rnd = (rnd * 134775813) + 1;
      }
   }
}

extern fn usleep(u32) void;
extern fn main() void {
   init(&board);
   do {
      draw(&board);
      usleep(100);
      next(&board);
   } while #t;
}