main.bzl

load("loop.bzl", "loop")
load("lib.bzl", "newlib")

WIDTH = 20
HEIGHT = 20
UPDATE_EVERY_N_LOOPS = 4

def reset_game(lib):
    lib.set("position", [(0, 0)])
    lib.set("direction", "s")
    lib.set("old_direction", "s")
    lib.set("iteration", 0)
    lib.set("ate_food", True)
    lib.set("food", (10, 10))

def update(lib):
    dir = lib.get("direction")
    pos = lib.get("position")
    x, y = pos[0]
    if dir == "a":
        x = x-1
        if x < 0:
            x = WIDTH - 1
    if dir == "d":
        x = x + 1
        if x >= WIDTH:
            x = 0
    if dir == "w":
        y = y - 1
        if y < 0:
            y = HEIGHT - 1
    if dir == "s":
        y = y + 1
        if y >= HEIGHT:
            y = 0

    food_x, food_y = lib.get("food")
    if x == food_x and y == food_y:
        lib.set("food", (lib.random(0, WIDTH), lib.random(0, HEIGHT)))
    else:
        pos.pop()

    alive = True
    for body_x, body_y in pos:
        if body_x == x and body_y == y:
            alive = False

    if alive:
        pos.insert(0, (x, y))
        lib.set("position", pos)
        lib.set("old_direction", dir)
    else:
        reset_game(lib)

def core_loop(lib):
    c = lib.read()
    old_dir = lib.get("old_direction")

    if c == "w" and old_dir != "s":
        lib.set("direction", c)
    if c == "s" and old_dir != "w":
        lib.set("direction", c)
    if c == "a" and old_dir != "d":
        lib.set("direction", c)
    if c == "d" and old_dir != "a":
        lib.set("direction", c)

    iteration = lib.get("iteration")
    if iteration % UPDATE_EVERY_N_LOOPS == 0:
        update(lib)
    lib.set("iteration", iteration + 1)

    for x in range(WIDTH):
        for y in range(HEIGHT):
            lib.set_px(x, y, "⬛")

    food_x, food_y = lib.get("food")
    lib.set_px(food_x, food_y, "🍎")

    for player_x, player_y in lib.get("position"):
        lib.set_px(player_x, player_y, "🟩")

    lib.flush()

def _main(repo_ctx):
    lib = newlib(repo_ctx, struct(
        w = WIDTH,
        h = HEIGHT,
    ))
    reset_game(lib)
    loop(core_loop, lib)

main = repository_rule(
    _main
)