class MenuState:
    def __init__(self, title, desc):
        self.title = title
        self.description = desc
        self.parent = None
        self.subs = []

    def add_submenu(self, menu):
        self.subs.append(menu)
        menu.parent = self

    def display_CLI(self):
        display_text = f'{self.title}\n'
        if self.parent != None:
            display_text += f'  b. Back'
        for i in range(0, len(self.subs)):
            sub = self.subs[i]
            display_text += f'  {i}. {sub.title}\n'
            display_text += f'    - {sub.description}\n'
        return display_text
    
    def nav_to_sub(self, sub_index):
        if sub_index <= len(self.subs):
            return self.subs[sub_index]
        else:
            return self
        
    def nav_to_parent(self):
        if self.parent != None:
            return self.parent
        else:
            return self


class LeafMenu(MenuState): 
    def __init__(self, title, desc):
        super.__init__(title, desc)
        self.subs = None
        self.actions = []

    def add_submenu(self, menu):
        return 
    
    def add_action(self, action):
        self.actions.append(action)
    
    def execute_action(self, act_index):
        if act_index <= len(self.actions):
            # what
            self.actions[act_index]()
        else:
            return