import pygame
import sys

DIMENSION = 8
SQ_SIZE = 800 // DIMENSION
MAX_FPS = 20
IMAGES = {}

# Load images
for i in range(1, 13):
    filename = 'images/b{}'.format(i)
    img = pygame.image.load(filename)
    IMAGES[filename] = img

for i in range(1, 13):
    filename = 'images/w{}'.format(i)
    img = pygame.image.load(filename)
    IMAGES[filename] = img

# Set up some colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (255, 0, 0)

# Set up the board
board = [[0] * DIMENSION for _ in range(DIMENSION)]
create_board(board)

# Set up some variables
valid_moves = []
player_clicks = []
game_over = False

# Set up the clock
clock = pygame.time.Clock()

def on_board(pos):
    """
    Check if a position is on the board.
    """
    (row, col) = pos
    return 0 <= row < DIM