#! /usr/bin/env python
'''
An example of using the collision_resolver module

Pops up a window populated by randomly placed little squares.
You control the big square with the direction keys.
'''

from random import randint
import pygame
from pygame.locals import *

RESOLUTION = (600,400)
green = (5,255,5)
avatar = None
avatarGroup = None
sceen = None
background = None
origBackground = None
screen = None

def main():
    clock = pygame.time.Clock()

    prepare()
    while True:
        clock.tick(2)
        retval = iterate()
        if not retval:
            return

def prepare():
    global screen
    pygame.init()
    screen = pygame.display.set_mode(RESOLUTION)
    Start()

def iterate():
    avatar.moveState[0] = randint(-9,9)
    avatar.moveState[1] = randint(-9,9)

    for ev in pygame.event.get():
        if ev.type == QUIT:
            return False
        if ev.type == KEYDOWN and ev.key == K_ESCAPE:
            return False

    #clear
    avatarGroup.clear( screen, background )

    #update
    avatarGroup.update()

    #draw
    avatarGroup.draw(screen)
    pygame.display.update()

    return True

def Start():
    global avatar, avatarGroup, background, origBackground, screen
    background = pygame.Surface( RESOLUTION )
    off_black = (40,10,0)
    background.fill( off_black )

    # avatar will be a green square in the center of the screen
    avatar = Avatar()

    fixedBackgroundSprites = pygame.sprite.Group()
    for block in GenerateRandomBlocks(30, RESOLUTION):
        if not block.rect.colliderect(avatar.rect):
            fixedBackgroundSprites.add( block )
    fixedBackgroundSprites.draw( background )

    avatar.collidables = fixedBackgroundSprites

    avatarGroup = pygame.sprite.Group()
    avatarGroup.add( avatar )

    screen.blit( background, (0,0) )
    pygame.display.flip()
    origBackground = background.copy()


class Avatar(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = pygame.Surface( (100,100) )
        self.image.fill( green )
        self.rect = self.image.get_rect()
        self.rect.center = (RESOLUTION[0]/2, RESOLUTION[1]/2)
        self.moveState = [0,0]
        self.collidables = None

    def update(self):
        if self.moveState[0] or self.moveState[1]:
            screen = pygame.display.get_surface()
            screen.blit( origBackground, (0,0) )
        self.rect.move_ip(*self.moveState)
        
class SimpleSprite(pygame.sprite.Sprite):
    def __init__(self, surface):
        pygame.sprite.Sprite.__init__(self)
        self.image = surface
        self.rect = self.image.get_rect()

def GenerateRandomBlocks( howMany, positionBounds ):
    lowerColorBound = (100,100,100)
    upperColorBound = (200,200,200)

    lowerXBound, lowerYBound = 0,0
    upperXBound, upperYBound = positionBounds

    lowerWidthBound, lowerHeightBound = 30,30
    upperWidthBound, upperHeightBound = 60,60

    for i in range(howMany):
        color = [ randint(lowerColorBound[i],upperColorBound[i])
                  for i in range(3) ]
        pos = [ randint(lowerXBound, upperXBound),
                randint(lowerYBound,upperYBound) ]
        size = [ randint(lowerWidthBound, upperWidthBound),
                 randint(lowerHeightBound, upperHeightBound) ]

        s = SimpleSprite( pygame.Surface(size) )
        s.image.fill( color )
        s.rect.topleft = pos
        yield s
    
if __name__ == '__main__':
    main()