import pygame
import sys
import random

# Initialize Pygame
pygame.init()

# Constants
WIDTH, HEIGHT = 800, 600
FPS = 60

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

# Player
player_width, player_height = 50, 50
player_x = WIDTH // 2 - player_width // 2
player_y = HEIGHT - player_height - 20
player_speed = 8

# Bullet
bullet_width, bullet_height = 5, 15
bullet_speed = 10
bullet_state = "ready"  # "ready" or "fire"
bullet_x, bullet_y = 0, 0

# Enemy
enemy_width, enemy_height = 50, 50
enemy_speed = 2
num_enemies = 5
enemies = []

for _ in range(num_enemies):
    enemy_x = random.randint(0, WIDTH - enemy_width)
    enemy_y = random.randint(50, 200)
    enemies.append([enemy_x, enemy_y])

# Set up the display
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption("Space Invaders")
clock = pygame.time.Clock()

def draw_player(x, y):
    pygame.draw.rect(screen, WHITE, [x, y, player_width, player_height])

def draw_bullet(x, y):
    pygame.draw.rect(screen, WHITE, [x, y, bullet_width, bullet_height])

def draw_enemy(x, y):
    pygame.draw.rect(screen, WHITE, [x, y, enemy_width, enemy_height])

def is_collision(enemy_x, enemy_y, bullet_x, bullet_y):
    distance = ((enemy_x - bullet_x)**2 + (enemy_y - bullet_y)**2)**0.5
    return distance < 27

def main():
    global player_x, bullet_x, bullet_y, bullet_state, bullet_speed, enemies

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()

        keys = pygame.key.get_pressed()
        if keys[pygame.K_LEFT] and player_x > 0:
            player_x -= player_speed
        if keys[pygame.K_RIGHT] and player_x < WIDTH - player_width:
            player_x += player_speed

        if keys[pygame.K_SPACE] and bullet_state == "ready":
            bullet_state = "fire"
            bullet_x = player_x + player_width // 2 - bullet_width // 2
            bullet_y = player_y

        # Move the bullet
        if bullet_state == "fire":
            bullet_y -= bullet_speed
            if bullet_y < 0:
                bullet_state = "ready"

        # Move the enemies
        for enemy in enemies:
            enemy[1] += enemy_speed
            if enemy[1] > HEIGHT:
                enemy[0] = random.randint(0, WIDTH - enemy_width)
                enemy[1] = random.randint(50, 200)

            # Check for collisions with bullet
            if is_collision(enemy[0], enemy[1], bullet_x, bullet_y):
                bullet_state = "ready"
                bullet_y = player_y
                enemy[0] = random.randint(0, WIDTH - enemy_width)
                enemy[1] = random.randint(50, 200)

        # Draw everything
        screen.fill(BLACK)
        draw_player(player_x, player_y)
        draw_bullet(bullet_x, bullet_y)
        for enemy in enemies:
            draw_enemy(enemy[0], enemy[1])

        # Update the display
        pygame.display.update()

        # Control the frame rate
        clock.tick(FPS)

if __name__ == "__main__":
    main()