Simple Collisions

import pygame
from pygame.locals import *

# Originally common.py
objs = []

# Originally configs.py
h = 500
w = 300
color_depth = 24
obj_width = 1

# Originally constants.py
# Colors
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
RED = (255, 0, 0)
GRAY = (186, 186, 186)
# Mouse
MAIN_BUTTON = 1
MIDDLE_BUTTON = 2
SECONDARY_BUTTON = 3
DRAG_AND_DROP = 2

# Originally contoller.py
def mouse(event):
    """Processes mouse events"""

    global clickPos
    global releasePos
    if event.type == MOUSEBUTTONUP:
        releasePos = pygame.mouse.get_pos()
        if event.button == MAIN_BUTTON:
            # Notice we are not handling drag and drops and considering
            # everything as a simple click.
            obj = collideAll(releasePos)
            if obj:
                obj.text = 'Hello World' if not obj.text else obj.text
            return MAIN_BUTTON
        elif event.button == MIDDLE_BUTTON:
            Circle(list(releasePos), 50)

    else:
        return False

clock = pygame.time.Clock()

def mainLoop():
    clock.tick(10)
    screen.fill(WHITE)
    for obj in objs:
        obj.draw()
    pygame.display.update()
    for event in pygame.event.get():
        mouse(event)
        if event.type == pygame.QUIT:
            pygame.quit()
            return None
    return True

# Originally objects.py
class Object:
    """Superclass for all objects.

    position - tuple
        Pair of screen coordinates.

    dimensions - list or array
        Pair of floats or integers representing width and height.
    """


    global objs

    def __init__(self, position, dimensions, color=BLACK):

        self.dimensions = dimensions
        self.position = position
        objs.append(self)

    def draw(self):
        """Should be defined in the subclass."""

        raise RuntimeError('draw() not defined for '+str(self))

class Circle(Object):
    """
    radius - integer

    density - float or integer
    """


    def __init__(self, position, radius, density=1, color=BLACK, text=None):

        Object.__init__(self, position, [radius, radius], color)
        self.color = color
        self.radius = radius
        self.text = text
        self.draw()

    def draw(self):

        pygame.draw.circle(
            screen,
            self.color,
            self.position,
            self.radius,
            obj_width
        )
        sendMsg(self.text, (self.position[0]-self.dimensions[0], self.position[1]-15))

# Originally graphics.py
pygame.init()
# The 0 below stands for "no flags"
screen = pygame.display.set_mode((w, h), 0, color_depth)

def sendMsg(msg, pos, font='monospace', fontsize=15, color=BLACK):

    myfont = pygame.font.SysFont(font, fontsize)
    label = myfont.render(msg, 1, color)
    screen.blit(label, pos)
    pygame.display.update()

def collideObject(position, obj):

    if ((position[0] >= obj.position[0]-obj.dimensions[0]) and (
            position[0] <= obj.position[0]+obj.dimensions[0])) and (
            (position[1] >= obj.position[1]-obj.dimensions[1]) and (
            position[1] <= obj.position[1]+obj.dimensions[1])):
        return obj
    else:
        return None

def collideAll(position, except_=None):

    for obj in objs:
        if not obj == except_:
            returnValue = collideObject(position, obj)
            if returnValue:
                return returnValue
    return None

screen.fill(WHITE)

# Originally __init__.py
try:
    while mainLoop():
        pass
except (KeyboardInterrupt, SystemExit):
    pass

raise SystemExit