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



def init_menus():
    main_menu = MenuState("NOS0S\nselect an option", "NOS0S MAIN")
    net = MenuState("net attacks", "tools to attack network devices")
    main_menu.add_submenu(net)
    return main_menu



def main():
    main_menu = init_menus()
    current_menu = main_menu
    while current_menu != None:
        print(current_menu.display_CLI())
        res = input('> ')
        if res == 'q':
            break
        elif res == 'b':
            current_menu = current_menu.nav_to_parent()
        else:
            try:
                selection = int(res)
                current_menu = current_menu.nav_to_sub(selection)
            except:
                print("Invalid input. Please try again.")


    
if __name__ == '__main__':
    main()