import random

snake_segments = [
    {'x': 2, 'y': 0},
    {'x': 1, 'y': 0},
    {'x': 0, 'y': 0},
]

timer = 0

direction_queue = ['right']

grid_x_count = 20
grid_y_count = 15

food_position = {
    'x': random.randint(0, grid_x_count - 1),
    'y': random.randint(0, grid_y_count - 1),
}

def update(dt):
    global timer

    timer += dt
    if timer >= 0.15:
        timer = 0

        if len(direction_queue) > 1:
            direction_queue.pop(0)

        next_x_position = snake_segments[0]['x']
        next_y_position = snake_segments[0]['y']

        if direction_queue[0] == 'right':
            next_x_position += 1
            if next_x_position >= grid_x_count:
                next_x_position = 0

        elif direction_queue[0] == 'left':
            next_x_position -= 1
            if next_x_position < 0:
                next_x_position = grid_x_count - 1

        elif direction_queue[0] == 'down':
            next_y_position += 1
            if next_y_position >= grid_y_count:
                next_y_position = 0

        elif direction_queue[0] == 'up':
            next_y_position -= 1
            if next_y_position < 0:
                next_y_position = grid_y_count - 1

        snake_segments.insert(0, {'x': next_x_position, 'y': next_y_position})
        snake_segments.pop()

def on_key_down(key):
    if (key == keys.RIGHT
    and direction_queue[-1] != 'right'
    and direction_queue[-1] != 'left'):
        direction_queue.append('right')

    elif (key == keys.LEFT
    and direction_queue[-1] != 'left'
    and direction_queue[-1] != 'right'):
        direction_queue.append('left')

    elif (key == keys.DOWN
    and direction_queue[-1] != 'down'
    and direction_queue[-1] != 'up'):
        direction_queue.append('down')

    elif (key == keys.UP
    and direction_queue[-1] != 'up'
    and direction_queue[-1] != 'down'):
        direction_queue.append('up')

def draw():
    screen.fill((0, 0, 0))

    cell_size = 15

    screen.draw.filled_rect(
        Rect(
            0, 0,
            grid_x_count * cell_size, grid_y_count * cell_size
        ),
        color=(70, 70, 70)
    )

    for segment in snake_segments:
        screen.draw.filled_rect(
            Rect(
                segment['x'] * cell_size, segment['y'] * cell_size,
                cell_size - 1, cell_size - 1
            ),
            color=(165, 255, 81)
        )

    screen.draw.filled_rect(
        Rect(
            food_position['x'] * cell_size, food_position['y'] * cell_size,
            cell_size - 1, cell_size - 1
        ),
        color=(255, 76, 76)
    )