"""
Sample Python/Pygame Programs
Simpson College Computer Science
http://programarcadegames.com/
http://simpson.edu/computer-science/

Explanation video: http://youtu.be/qbEEcQXw8aw
"""

import pygame
import random

# Define some colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED = (255, 0, 0)


class Block(pygame.sprite.Sprite):
    """
    This class represents the ball
    It derives from the "Sprite" class in Pygame
    """
    def __init__(self, color, width, height):
        """ Constructor. Pass in the color of the block,
        and its x and y position. """
        # Call the parent class (Sprite) constructor
        super().__init__()

        # Create an image of the block, and fill it with a color.
        # This could also be an image loaded from the disk.
        self.image = pygame.Surface([width, height])
        self.image.fill(color)

        # Fetch the rectangle object that has the dimensions of the image
        # image.
        # Update the position of this object by setting the values
        # of rect.x and rect.y
        self.rect = self.image.get_rect()

    def reset_pos(self):
        """ Reset position to the top of the screen, at a random x location.
        Called by update() or the main program loop if there is a collision.
        """
        self.rect.y = random.randrange(-300, -20)
        self.rect.x = random.randrange(0, screen_width)

    def update(self):
        """ Called each frame. """

        # Move block down one pixel
        self.rect.y += 1

        # If block is too far down, reset to top of screen.
        if self.rect.y > 410:
            self.reset_pos()


class Player(Block):
    """ The player class derives from Block, but overrides the 'update'
    functionality with new a movement function that will move the block
    with the mouse. """
    def update(self):
        # Get the current mouse position. This returns the position
        # as a list of two numbers.
        pos = pygame.mouse.get_pos()

        # Fetch the x and y out of the list,
        # just like we'd fetch letters out of a string.
        # Set the player object to the mouse location
        self.rect.x = pos[0]
        self.rect.y = pos[1]

# Initialize Pygame
pygame.init()

# Set the height and width of the screen
screen_width = 700
screen_height = 400
screen = pygame.display.set_mode([screen_width, screen_height])

# This is a list of 'sprites.' Each block in the program is
# added to this list. The list is managed by a class called 'Group.'
block_list = pygame.sprite.Group()

# This is a list of every sprite. All blocks and the player block as well.
all_sprites_list = pygame.sprite.Group()

for i in range(50):
    # This represents a block
    block = Block(BLACK, 20, 15)

    # Set a random location for the block
    block.rect.x = random.randrange(screen_width)
    block.rect.y = random.randrange(screen_height)

    # Add the block to the list of objects
    block_list.add(block)
    all_sprites_list.add(block)

# Create a red player block
player = Player(RED, 20, 15)
all_sprites_list.add(player)

# Loop until the user clicks the close button.
done = False

# Used to manage how fast the screen updates
clock = pygame.time.Clock()

score = 0

# -------- Main Program Loop -----------
while not done:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            done = True

    # Clear the screen
    screen.fill(WHITE)

    # Calls update() method on every sprite in the list
    all_sprites_list.update()

    # See if the player block has collided with anything.
    blocks_hit_list = pygame.sprite.spritecollide(player, block_list, False)

    # Check the list of collisions.
    for block in blocks_hit_list:
        score += 1
        print(score)

        # Reset block to the top of the screen to fall again.
        block.reset_pos()

    # Draw all the spites
    all_sprites_list.draw(screen)

    # Limit to 20 frames per second
    clock.tick(20)

    # Go ahead and update the screen with what we've drawn.
    pygame.display.flip()

pygame.quit()