#!/usr/bin/env python
#-*- coding:utf-8 -*-
import sys
import pygame

class Object:
    def __init__(self, img_path, screen):
        self.surface = pygame.image.load(img_path)
        self.rect = self.surface.get_rect()
        self.screen = screen
        self.box = screen.get_size()
        self._speed = 1
        self.speed = 1
        self.accel = .0
        self.control = {'type':1, 'target':None}
    def move(self, dirs=None):
        if not self.collided():
            if self.control['type'] == 1:
                if dirs[pygame.K_UP]:
                    self.rect = self.rect.move((0,-self.speed))
                if dirs[pygame.K_DOWN]:
                    self.rect = self.rect.move((0,self.speed))
                if dirs[pygame.K_LEFT]:
                    self.rect = self.rect.move((-self.speed,0))
                if dirs[pygame.K_RIGHT]:
                    self.rect = self.rect.move((self.speed,0))
            elif self.control['type'] == 2:
                target = self.control['target']
                if self.rect.top > target.rect.bottom:
                    self.rect = self.rect.move((0,-self.speed))
                if self.rect.bottom < target.rect.top:
                    self.rect = self.rect.move((0,self.speed))
                if self.rect.left > target.rect.right:
                    self.rect = self.rect.move((-self.speed,0))
                if self.rect.right < target.rect.left:
                    self.rect = self.rect.move((self.speed,0))
            self.speed += self.accel
        else: self.stop()
    def collided(self):
        if self.rect.right > self.box[0]:
            self.rect.right -= self._speed
            return True
        if self.rect.left < 0:
            self.rect.left += self._speed
            return True
        if self.rect.bottom > self.box[1]:
            self.rect.bottom -= self._speed
            return True
        if self.rect.top < 0:
            self.rect.top += self._speed
            return True
        return False
    def stop(self):
        self.speed = self._speed
    def update(self):
        self.screen.blit(self.surface, self.rect)

if __name__ == '__main__':
    pygame.init()
    screensize = 400, 300
    screen = pygame.display.set_mode(screensize)

    obj1 = Object("/usr/share/icons/hicolor/"\
                      "48x48/apps/gdu-emblem-raid0.png", screen)
    obj1.accel = 0.05

    obj2 = Object("/usr/share/icons/hicolor/"\
                      "48x48/apps/gdu-emblem-raid1.png", screen)

    obj2.rect.bottom += screensize[1]/2
    obj2.control['type'] = 2
    obj2.control['target'] = obj1
    while True:
        event = pygame.event.poll()
        if event.type == pygame.QUIT: sys.exit(0)
        key_status = pygame.key.get_pressed()
        if not any(key_status):
            obj1.stop()
        else:
            obj1.move(key_status)
        obj2.move()
        screen.fill((255,255,255))
        obj1.update()
        obj2.update()
        pygame.time.wait(30)
        pygame.display.flip()