# Create a simple box sprite
# Draw three instances of the sprite and make them bounce up and down

# Task: instead of just dislaying boxes, use the ball.gif image from the website
#       You'll want to go back to the first tutorial to do this
#       Uh-oh... one of the balls disappears.  Why?  Fix it.
# Task: Increase the screen size to 400 x 400
#       Make sure the balls still bounce off the bottom!
# Task: make each box start at a random location
#       You can set the position of a box on creation
# Challenge: can you make the balls bounce at an angle?

import sys, os, pygame
from pygame.locals import *

class Box(pygame.sprite.Sprite):
    def __init__(self, color, initial_position):
        pygame.sprite.Sprite.__init__(self)
      
        self.image = pygame.Surface([15, 15])
        self.image.fill(color)

        # Make our top-left corner the passed-in location.
        self.rect = self.image.get_rect()
        self.rect.topleft = initial_position

        self.going_down = True # Start going downwards
        self.next_update_time = 0 # update() hasn't been called yet.

    def update(self, current_time, bottom):
        # update every 1/100th of a second
        if self.next_update_time < current_time:
            # If we're at the top or bottom of the screen, switch directions.
            if self.rect.bottom == bottom - 1:
                self.going_down = False
            elif self.rect.top == 0:
                self.going_down = True
     
            # Move our position up or down by one pixel
            if self.going_down:
                self.rect.top += 1
            else: self.rect.top -= 1

            self.next_update_time = current_time + 10
            

pygame.init()
screen = pygame.display.set_mode([150, 150])

boxes = [] # create a list of box sprites
boxes.append(Box([255, 0, 0], [0, 0])) # Make a red box in the top left
boxes.append(Box([0, 255, 0], [0, 60])) # Make a green box mid-screen
boxes.append(Box([0, 0, 255], [0, 120])) # Make a blue box at the bottom of the creen

def input(events):
   for event in events:
      if event.type == QUIT:
         return False
   return True
         
going = True

while going:
    screen.fill([200, 15, 30]) # set background color

    time = pygame.time.get_ticks()

    for b in boxes: # loop over the boxes
        b.update(time, 150) # update the position of the box
        screen.blit(b.image, b.rect) # blit each

    going = input(pygame.event.get())
    pygame.display.update() # update the screen
pygame.quit()