import os
from time import sleep

clear = lambda: os.system('clear') if os.name == 'posix' else os.system('cls')
tab='\n'+' '*4

def excp_handler(function):
    def wrapper(*args, **kwargs):
        try:
            function(*args, **kwargs)
        except Exception:
            print("Lee atentamente las instrucciones e intenta nuevamente")
            sleep(3)
    return wrapper

def opcs_default():
    print("""    v) Volver
    s) Salir""")

def enter_continue():
    input("\n\tPresiona Enter para continuar\n")

@excp_handler
def run_func(func):
    print(tab, func.__doc__, '\n')
    func()
    enter_continue()

def user_input(i):
    try:
        selection = input("\n    Ingresa una opción: ")
        if selection in 'sSvV':
            return selection.lower()
        selection = int(selection)
        if 0 < selection <= i:
            clear()
            return selection
        else:
            raise Exception
    except Exception:
        print("Debes ingresar una opción válida")
        sleep(2)
        return 0

def print_challenges(exercises):
    ex = exercises()
    i = 0
    funcs = list(vars(exercises))[1:-3]
    while i < len(funcs):
        print(f"{i+1}) ".rjust(8), end='')
        print(vars(exercises).get(funcs[i]).__doc__)
        i+=1
    opcs_default()
    return i, ex