class StatePool:

    def GetInst(self, cls):
        if cls in self.__dict__.keys():
            return self.__dict__[cls];
        else:
            self.__dict__[cls] = cls();
            return self.__dict__[cls];

    def __init__(self):
        self.__dict__ = dict();

class HeroState:
    __pool__ = StatePool();
    def __init__(self, name = 'default_name'):
        self.name = name;

    @classmethod
    def GetInst(self, cls):
        return HeroState.__pool__.GetInst(cls);

class Standing(HeroState):
    def __str__(self):
        return 'Hero is Standing';

    def on_event(self, event):
        if event == 'go':
            return HeroState.GetInst(Moving);
        elif event == 'shoot':
            HeroState.GetInst(Shooting).prev = self
            return HeroState.GetInst(Shooting);
        else:
            return self;


class Moving(HeroState):
    def __str__(self):
        return 'Hero is Moving';

    def on_event(self, event):
        if event == 'shoot':
            HeroState.GetInst(Shooting).prev = self
            return HeroState.GetInst(Shooting);
        elif event == 'stop':
            return HeroState.GetInst(Standing);
        else:
            return self;

class Shooting(HeroState):
    def __init__(self):
        self.prev = HeroState.GetInst(Standing);

    def __str__(self):
        return 'Hero is Shooting';

    def on_event(self, event):
        return self.prev;



class Hero:
    def __init__(self):
        self.current_hero_state = HeroState.GetInst(Standing);

    def ProcessEvents(self):
        while True:
            print(self.current_hero_state.__str__())
            event = input('Enter event:')
            if event == 'exit':
                break;
            else:
                self.current_hero_state = self.current_hero_state.on_event(event);




hero = Hero();
hero.ProcessEvents();