import pygame
import sys
import random

# Initialize Pygame
pygame.init()

# Constants
WIDTH, HEIGHT = 800, 600
FPS = 50
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)

# Paddle Constants
PADDLE_WIDTH, PADDLE_HEIGHT = 15, 100
PADDLE_SPEED = 10

# Ball Constants
BALL_SIZE = 20
BALL_SPEED_X = 5
BALL_SPEED_Y = 5

# Create game window
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Pong")
clock = pygame.time.Clock()

# Paddle Class
class Paddle(pygame.sprite.Sprite):
    def __init__(self, x, y):
        super().__init__()
        self.image = pygame.Surface((PADDLE_WIDTH, PADDLE_HEIGHT))
        self.image.fill(WHITE)
        self.rect = self.image.get_rect(center=(x, y))

    def update(self, keys):
        if keys[pygame.K_w] and self.rect.top > 0:
            self.rect.y -= PADDLE_SPEED
        if keys[pygame.K_s] and self.rect.bottom < HEIGHT:
            self.rect.y += PADDLE_SPEED

# Ball Class
class Ball(pygame.sprite.Sprite):
    def __init__(self):
        super().__init__()
        self.image = pygame.Surface((BALL_SIZE, BALL_SIZE), pygame.SRCALPHA)
        pygame.draw.circle(self.image, WHITE, (BALL_SIZE // 2, BALL_SIZE // 2), BALL_SIZE // 2)
        self.rect = self.image.get_rect(center=(WIDTH // 2, HEIGHT // 2))
        self.speed_x = BALL_SPEED_X * random.choice([-1, 1])
        self.speed_y = BALL_SPEED_Y * random.choice([-1, 1])

    def update(self):
        self.rect.x += self.speed_x
        self.rect.y += self.speed_y

        # Ball bouncing off walls
        if self.rect.top <= 0 or self.rect.bottom >= HEIGHT:
            self.speed_y = -self.speed_y

# Create sprites
all_sprites = pygame.sprite.Group()
paddles = pygame.sprite.Group()
balls = pygame.sprite.Group()

# Create paddles
left_paddle = Paddle(20, HEIGHT // 2)
right_paddle = Paddle(WIDTH - 20, HEIGHT // 2)
all_sprites.add(left_paddle, right_paddle)
paddles.add(left_paddle, right_paddle)

# Create ball
ball = Ball()
all_sprites.add(ball)
balls.add(ball)

# Score
score_left = 0
score_right = 0

# Font for displaying score
font = pygame.font.Font(None, 36)

# Game loop
running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    keys = pygame.key.get_pressed()
    left_paddle.update(keys)
    right_paddle.update(keys)

    balls.update()

    # Ball bouncing off paddles
    if pygame.sprite.spritecollide(left_paddle, balls, False):
        ball.speed_x = -ball.speed_x
    elif pygame.sprite.spritecollide(right_paddle, balls, False):
        ball.speed_x = -ball.speed_x

    # Ball missed by left paddle
    if ball.rect.left <= 0:
        ball.rect.center = (WIDTH // 2, HEIGHT // 2)
        ball.speed_x = BALL_SPEED_X
        ball.speed_y = BALL_SPEED_Y
        score_right += 1

    # Ball missed by right paddle
    elif ball.rect.right >= WIDTH:
        ball.rect.center = (WIDTH // 2, HEIGHT // 2)
        ball.speed_x = -BALL_SPEED_X
        ball.speed_y = BALL_SPEED_Y
        score_left += 1

    # Draw everything
    screen.fill(BLACK)
    pygame.draw.line(screen, WHITE, (WIDTH // 2, 0), (WIDTH // 2, HEIGHT), 2)

    # Draw score
    score_text = font.render(f"{score_left} - {score_right}", True, WHITE)
    screen.blit(score_text, (WIDTH // 2 - 50, 20))

    all_sprites.draw(screen)

    # Update display
    pygame.display.flip()

    # Cap the frame rate
    clock.tick(FPS)

# Quit the game
pygame.quit()
sys.exit()