import pygame

pygame.init()

white = (255,255,255)
black = (0,0,0)
red = (255,0,0)

display_width = 800
display_height  = 600

gameDisplay = pygame.display.set_mode((display_width,display_height))
pygame.display.set_caption('Slither')

gameExit = False

lead_x = display_width/2
lead_y = display_height/2

lead_x_change = 0
lead_y_change = 0

clock = pygame.time.Clock()

block_size = 10
FPS = 30


while not gameExit:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            gameExit = True
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                lead_x_change = -block_size
                lead_y_change = 0
            elif event.key == pygame.K_RIGHT:
                lead_x_change = block_size
                lead_y_change = 0
            elif event.key == pygame.K_UP:
                lead_y_change = -block_size
                lead_x_change = 0
            elif event.key == pygame.K_DOWN:
                lead_y_change = block_size
                lead_x_change = 0

    if lead_x >= display_width or lead_x < 0 or lead_y >= display_height or lead_y < 0:
        gameExit = True

        

                
        

    lead_x += lead_x_change
    lead_y += lead_y_change
    gameDisplay.fill(white)
    pygame.draw.rect(gameDisplay, black, [lead_x,lead_y,block_size,block_size])
    pygame.display.update()

    clock.tick(FPS)
    

pygame.quit()
quit()