# Implementation of classic arcade game Pong

import simplegui
import random

# initialize globals - pos and vel encode vertical info for paddles
WIDTH = 600
HEIGHT = 400
BALL_RADIUS = 20
PAD_WIDTH = 8
PAD_HEIGHT = 80
HALF_PAD_WIDTH = PAD_WIDTH / 2
HALF_PAD_HEIGHT = PAD_HEIGHT / 2
PADDLE_VEL = 5
LEFT = False
RIGHT = True

paddle1_pos = HEIGHT/2
paddle2_pos = HEIGHT/2
paddle1_vel = 0
paddle2_vel = 0
score1 = 0
score2 = 0

# initialize ball_pos and ball_vel for new bal in middle of table
ball_pos = [WIDTH/2, HEIGHT/2]
ball_vel = [1, -1]

# if direction is RIGHT, the ball's velocity is upper right, else upper left
def spawn_ball(direction):
    global ball_pos, ball_vel # these are vectors stored as lists
    ball_pos = [WIDTH/2, HEIGHT/2]

    ball_vel[0] = -random.randrange(12,24) / 100
    if direction == True:
        ball_vel[0] = - ball_vel[0]
    ball_vel[1] = -random.randrange(60, 180) / 100

# define event handlers
def new_game():
    global paddle1_pos_top, paddle2_pos_bot, paddle1_vel, paddle2_vel
    global ball_pos, ball_vel # these are numbers
    global score1, score2  # these are ints
    ball_pos = [WIDTH/2, HEIGHT/2]
    paddle1_pos = [0, HEIGHT/2]
    paddle2_pos = [WIDTH, HEIGHT/2]
    score1 = 0
    score2 = 0
    spawn_ball(random.choice([LEFT, RIGHT]))

def draw(canvas):
    global score1, score2, paddle1_pos, paddle2_pos, ball_pos, ball_vel, direction


    # draw mid line and gutters
    canvas.draw_line([WIDTH / 2, 0],[WIDTH / 2, HEIGHT], 4, "Red")
    canvas.draw_line([PAD_WIDTH, 0],[PAD_WIDTH, HEIGHT], 4, "Red")
    canvas.draw_line([WIDTH - PAD_WIDTH, 0],[WIDTH - PAD_WIDTH, HEIGHT], 4, "Red")

    # draw ball
    canvas.draw_circle(ball_pos, 15, 12, "Blue", "Blue")
    # update paddle's vertical position, keep paddle on the screen
        #left player paddle
    if ((paddle1_pos <= HEIGHT - PAD_HEIGHT) and (paddle1_vel > 0)) or ((paddle1_pos >= 0) and (paddle1_vel < 0)):
        paddle1_pos += paddle1_vel
        #right player paddle
    elif ((paddle2_pos <= HEIGHT - PAD_HEIGHT) and (paddle2_vel > 0)) or ((paddle2_pos >= 0) and (paddle2_vel < 0)):
        paddle2_pos += paddle2_vel

    # draw paddles
    canvas.draw_line([0, paddle1_pos], [0, paddle1_pos + PAD_HEIGHT], PAD_WIDTH, "White")
    canvas.draw_line([WIDTH, paddle2_pos], [WIDTH, paddle2_pos + PAD_HEIGHT], PAD_WIDTH, "White")

    # determine whether paddle and ball collide
    # update ball
    ball_pos[0] += ball_vel[0]
    ball_pos[1] += ball_vel[1]

    #upper and lower wall collisions
    if ball_pos[1] <= 20:
        ball_vel[1] = - ball_vel[1]
    elif ball_pos[1] >= HEIGHT - 20:
        ball_vel[1] = - ball_vel[1]

    #Checking for collision of ball with paddles
        #checking left side for collision
    if ball_pos[0] <= HALF_PAD_WIDTH + BALL_RADIUS:
        if((ball_pos[1] > paddle1_pos + PAD_HEIGHT) and (ball_pos[1] < HEIGHT)):
            score2 += 1
            spawn_ball(RIGHT)
        elif ((ball_pos[1] < paddle1_pos) and (ball_pos[1] > 0)):
            score2 += 1
            spawn_ball(RIGHT)
        elif ((ball_pos[1] >= paddle1_pos) and (ball_pos[1] <= paddle1_pos + PAD_HEIGHT + 2)):
            ball_vel[0] = - ball_vel[0]
            ball_vel[0] += 0.1 * ball_vel[0]

        #checking right side for collision
    if ball_pos[0] >= WIDTH - HALF_PAD_WIDTH - BALL_RADIUS:
        if((ball_pos[1] > paddle2_pos + PAD_HEIGHT) and (ball_pos[1] < HEIGHT)):
            score1 += 1
            spawn_ball(LEFT)
        elif ((ball_pos[1] < paddle2_pos - PAD_HEIGHT) and (ball_pos[1] > 0)):
            score1 += 1
            spawn_ball(LEFT)
        elif ((ball_pos[1] >= paddle2_pos) and (ball_pos[1] <= paddle2_pos + PAD_HEIGHT + 2)):
            ball_vel[0] = - ball_vel[0]
            ball_vel[0] += 0.1 * ball_vel[0]

    # draw scores
    canvas.draw_text(str(score1), (440, 40), 40, "White")
    canvas.draw_text(str(score2), (140, 40), 40, "White")

def keydown(key):
    global paddle1_vel, paddle2_vel

    #left player paddle
    if key == simplegui.KEY_MAP["w"]:
        paddle1_vel = -PADDLE_VEL
    elif key == simplegui.KEY_MAP["s"]:
        paddle1_vel = PADDLE_VEL

    #right player paddle
    if key == simplegui.KEY_MAP["up"]:
        paddle2_vel = -PADDLE_VEL
    elif key == simplegui.KEY_MAP["down"]:
        paddle2_vel = PADDLE_VEL

def keyup(key):
    global paddle1_vel, paddle2_vel, paddle_vel
    #player1
    if key == simplegui.KEY_MAP["w"]:
        paddle1_vel = 0
    elif key == simplegui.KEY_MAP["s"]:
        paddle1_vel = 0

    #player2
    if key == simplegui.KEY_MAP["down"]:
        paddle2_vel = 0
    elif key == simplegui.KEY_MAP["up"]:
        paddle2_vel = 0

# create frame
frame = simplegui.create_frame("Pong", WIDTH, HEIGHT)
frame.add_button("Restart", new_game, 100)
frame.set_draw_handler(draw)
frame.set_keydown_handler(keydown)
frame.set_keyup_handler(keyup)


# start frame
new_game()
frame.start()