import pygame
from pygame.locals import *
import os
import sensor
import time

media_path = "./media"
images = {}

def load_image(filename, convert=False, alpha=False, reload=False):
    if filename in images and not reload:
        return images.get(filename)
    filepath = os.path.join(media_path, filename)
    image = pygame.image.load(filepath)
    if convert:
        if alpha:
            image.convert_alpha()
        else:
            image.convert()
    images[filename] = image
    return image

def blit_cursor(screen, cursor):
    cursrect = cursor.get_rect()
    cursrect.center = pygame.mouse.get_pos()
    screen.blit(cursor, cursrect.topleft)

def out(sensor, event):
    print "Ueber Button bewegt,", sensor
    
def clicked(sensor, event):
    print "Button geklickt", sensor, " - target:", sensor.target
    
class QuitButton(sensor.Sensor):
    def __init__(self, parent, surf, **kw):
        if not "name" in kw:
            kw["name"] = "Quitbutton"
        sensor.Sensor.__init__(self, parent=parent, **kw)
        self.surf_dict = self.split_surf(surf)
        self.target = self.surf_dict["normal"]
    
    def split_surf(self, surf):
        rect = surf.get_rect()
        halfheight = rect.height/2
        quit_buttons = {"normal":surf.subsurface(Rect(0, 0, rect.width, halfheight)),
                        "hover":surf.subsurface(Rect(0, rect.height-halfheight, rect.width, halfheight))}
        return quit_buttons
    
    def mouse_enter(self, sensor):
        self.target = self.surf_dict["hover"]
    def mouse_leave(self, sensor):
        self.target = self.surf_dict["normal"]
    def mouse_drag(self, sensor, event=None):
        self.move_offset(event.rel)
        
    def mouse_button_down(self, sensor, event=None):
        if event.button == 1:
            self.lift()
        if event.button == 3:
            pygame.quit()
            raise SystemExit

def main():
    pygame.init()

    clock = pygame.time.Clock()
    background = load_image("bg.jpg", convert=False)
    screen = pygame.display.set_mode(background.get_rect().size)
    cursor = load_image("cursor.gif", alpha=True)
    button = load_image("button.jpg")
    quit_button_surf= load_image("quit_button.gif")
    
    desktop = sensor.Sensor(name="main", rect=screen.get_rect())
    button_sensor = sensor.Sensor(parent=desktop, 
                                  name="button", 
                                  offset=(50, 50),
                                  target=button)
    button_sensor.mouse_button_down = clicked
    button_sensor.mouse_motion = out
    
    quit_button = QuitButton(parent=desktop, surf=quit_button_surf, offset=(200, 200))
    quit_button2 = QuitButton(parent=desktop, surf=quit_button_surf, 
                name="Quitbutton 2", offset=(100, 300))
    
    background.convert()
    pygame.mouse.set_visible(False)

    while True:
        #diff = pygame.mouse.get_rel()
        clock.tick(40)
        screen.blit(background, (0, 0))
        screen.blit(button, button_sensor.rect)
        for widget in desktop.collect_stack():
            if widget in (quit_button, quit_button2):
                screen.blit(widget.target, widget.rect)
        blit_cursor(screen, cursor)
        events = pygame.event.get()
        desktop.check(events)
        pygame.display.flip()
        for event in events:
            if event.type == QUIT:
                exit()
                
if __name__ == "__main__":
    main()