# Space Asteroids game for a Raspberry Pi
# Uses Pygame Zero and gpio zero
# Save as space-asteroids.py with the image files in the images sub-directory
# Run using pgzrun space-asteroids.py
# For more details see https://www.penguintutor.com/space-asteroids 
# Version 1.2 (new GPIO port allocations)
from gpiozero import Button, LED
import random

WIDTH = 600
HEIGHT = 500

PIN_LEFT = 4    
PIN_MISSILE = 3 
PIN_RIGHT = 2 
PIN_LED = 14
button_left = Button(PIN_LEFT)
button_missile = Button(PIN_MISSILE)
button_right = Button(PIN_RIGHT)

# The Launcher
launcher = Actor('launcher')
launcher.pos = int(WIDTH/2),HEIGHT-50
launcher_speed = 2

# The Asteroid
ASTEROID_SIZE = 50,46
asteroid = Actor('asteroid')
asteroid.pos = (random.randint(ASTEROID_SIZE[0]/2, WIDTH-(ASTEROID_SIZE[0]/2)), ASTEROID_SIZE[1])
asteroid_speed = 1

# The missile
MISSILE_SIZE = 20,43
missile = Actor('missile')
# initially set missile position in top corner
missile.pos = 0,0
missile_speed = 10
# Status 0 = not fired, 1 = fired
missile_status = 0

# The LED output
led = LED(PIN_LED)

# Status 0 = stop, 1 = playing game
game_status = 0
game_score = 0

def draw():
    if game_status == 0:
        screen.draw.text("Press ENTER to start", (100, 300), color="white", fontsize=32)
    if game_status == 1:
        screen.clear()
        # display score
        screen.draw.text("Score: " + str(game_score), (WIDTH-100, 50), color="blue", fontsize=24)
        launcher.draw()
        # Each draw loop move asteroid down 1 position
        move_asteroid()
        asteroid.draw()
        # If missile launched move missile up and show
        if missile_status > 0 :
            move_missile()
            missile.draw()
        # Detect if missile / asteroid has hit etc
        detect_hits()
    
def update():
    global game_status, game_score, missile_status, asteroid_speed
    if game_status == 0:
        if keyboard.RETURN:
            game_status = 1
            asteroid.pos = (random.randint(ASTEROID_SIZE[0]/2, WIDTH-(ASTEROID_SIZE[0]/2)), ASTEROID_SIZE[1])
            game_score = 0
            asteroid_speed = 1
    elif game_status == 1:
        # Keyboard movement
        if keyboard.right or button_right.is_pressed :
            move_launcher(launcher_speed)
        if keyboard.left or button_left.is_pressed :
            move_launcher(-1 * launcher_speed)
        # If missile not fired then it can be fired
        if missile_status == 0:
            if keyboard.space or button_missile.is_pressed :
                # set position to location of launcher
                missile.pos = (launcher.x, HEIGHT - 50)
                # set it fired
                missile_status = 1


# Move launcher allowing, prevent overrunning
def move_launcher(distance):
    newpos = launcher.x + distance
    if (newpos < 50):
        newpos = 50
    elif (newpos > WIDTH-50):
        newpos = WIDTH-50
    launcher.x = newpos


# Move asteroid position and check for hits
def move_asteroid():
    global game_status
    # Move position down 
    asteroid.pos = (asteroid.x, asteroid.y+asteroid_speed)

# If missile launched then move it up appropriate distance 
def move_missile():
    global missile_status
    # Only move / draw if missile is fired
    if missile_status > 0:
        missile.pos = (missile.x, missile.y - missile_speed)
        # Near top and not collided so stop missile
        if missile.y < 10:
            missile_status = 0

# Check for hits between asteroid and ground / missile
def detect_hits():
    global game_status, game_score, missile_status, asteroid_speed
    # Check if we have hit the ground (game over)
    if asteroid.y >= HEIGHT-(ASTEROID_SIZE[1]/2):
        screen.draw.text("Game Over", (100, 100), color="red", fontsize=32)
        # Stop the game
        game_status = 0
    # check if missile has hit asteroid
    if missile_status == 1 and asteroid.collidepoint(missile.pos):
        # When hit asteroid add point and start new
        hit_asteroid()
        missile_status = 0
        # increase asteroid_speed
        asteroid_speed += 1
        game_score += 1

    
# When hit reset the asteroid position
def hit_asteroid():
    # Set new position
    asteroid.pos = (random.randint(ASTEROID_SIZE[0]/2, WIDTH-(ASTEROID_SIZE[0]/2)), ASTEROID_SIZE[1])
    led.on()
    clock.schedule_unique(led.off, 0.5)