import pygame
import sys

# Initialize Pygame
pygame.init()

# Set screen dimensions
WIDTH, HEIGHT = 800, 600
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Bouncing Ball with Trail")

# Colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (255, 0, 0)

# Ball properties
ball_radius = 20
ball_color = RED
ball_position = [WIDTH // 2, HEIGHT // 2]  # Starting position of the ball
ball_speed = [5, 5]  # Movement speed of the ball
trail_length = 20  # Number of previous positions to draw as a trail
trail = []  # List to store previous positions of the ball

# Main loop
while True:
    # Event handling
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    # Update ball position
    ball_position[0] += ball_speed[0]
    ball_position[1] += ball_speed[1]

    # Check for collisions with walls
    if ball_position[0] + ball_radius >= WIDTH or ball_position[0] - ball_radius <= 0:
        ball_speed[0] = -ball_speed[0]
    if ball_position[1] + ball_radius >= HEIGHT or ball_position[1] - ball_radius <= 0:
        ball_speed[1] = -ball_speed[1]

    # Add current position to the trail
    trail.insert(0, (int(ball_position[0]), int(ball_position[1])))
    if len(trail) > trail_length:
        trail.pop()

    # Clear the screen
    screen.fill(BLACK)

    # Draw the trail
    for i, pos in enumerate(trail):
        alpha = int(255 * (1 - i / trail_length))
        pygame.draw.circle(screen, (ball_color[0], ball_color[1], ball_color[2], alpha), pos, ball_radius)

    # Draw the ball
    pygame.draw.circle(screen, ball_color, (int(ball_position[0]), int(ball_position[1])), ball_radius)

    # Update the display
    pygame.display.flip()

    # Control the frame rate
    pygame.time.Clock().tick(60)