package main

import "core:fmt"
import "core:math/rand"
import "core:strings"
import "core:time"

WIDTH :: 64
HEIGHT :: 64
AREA :: WIDTH * HEIGHT
state: [AREA]bool

main :: proc() {
	fmt.print("\e[2J") // clear screen
	for i in 0 ..< AREA do state[i] = bool(rand.uint32() & 1)
	for {
		print_board()
		update_board()
		time.sleep(time.Millisecond * 50)
	}
}

print_board :: proc() {
	fmt.print("\e[u") // reset cursor
	for y := 0; y < HEIGHT; y += 2 {
		line := strings.builder_make()
		defer strings.builder_destroy(&line)

		for x in 0 ..< WIDTH {
			top := state[x + y * WIDTH]
			bot := state[x + (y + 1) * WIDTH]
			c: rune
			switch {
			case top && bot:
				c = '█'
			case top && !bot:
				c = '▀'
			case !top && bot:
				c = '▄'
			case:
				c = ' '
			}
			strings.write_rune(&line, c)
		}
		fmt.println(strings.to_string(line))
	}
}

update_board :: proc() {
	new_state: [AREA]bool = ---
	for x in 0 ..< WIDTH {
		for y in 0 ..< HEIGHT {
			count := 0
			for dx in -1 ..= 1 {
				px := (x + dx + WIDTH) % WIDTH
				for dy in -1 ..= 1 {
					py := (y + dy + HEIGHT) % HEIGHT
					if state[px + py * WIDTH] do count += 1
				}
			}
			cell := state[x + y * WIDTH]
			new_cell := (count == 3 && !cell) || (cell && count < 5 && count > 2)
			new_state[x + y * WIDTH] = new_cell
		}
	}
	for i in 0 ..< AREA {
		state[i] = new_state[i]
	}
}