from typing import Callable
import random
from functools import wraps

from django.utils import timezone


def random_str(typename: str, randomlength: int = 16) -> Callable[[None], str]:
    """Parameter:
    ----------
    type: 'common' [A-Za-z0-9]; 'lower' [a-z0-9]"""
    common = "AaBbCcDdEeFfGgHhJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz0123456789"
    lower = "abcdefghijklmnopqrstuvwxyz0123456789"

    if typename == 'common':
        chars = common
    elif typename == 'lower':
        chars = lower
    else:
        raise ValueError

    def _do() -> str:
        length = len(chars) - 1
        ret = "".join([chars[random.randint(0, length)] for _ in range(randomlength)])
        return ret

    return _do


def create_random_unique_str(rand_func: Callable[[None], str]):
    time_string = None
    list_string = []

    def create_random(rand_func: Callable[[None], str]):
        timestr = timezone.now().timestamp()
        timestr = str(int(timestr))
        ranstr = rand_func()
        ret = timestr + ranstr
        return ret, timestr

    def get_unique_str():
        nonlocal time_string
        nonlocal list_string
        while True:
            ret, timestr = create_random(rand_func)
            if time_string != timestr:
                time_string = timestr
                list_string = [ret]
                return ret
            else:
                if ret not in list_string:
                    list_string.append(ret)
                    return ret

    def decrator_func(func):
        @wraps(func)
        def _do():
            return get_unique_str()
        return _do

    return decrator_func
    # return get_unique_str


@create_random_unique_str(random_str('common', 2))
def default_nickname() -> str:
    pass


@create_random_unique_str(random_str('lower', 1))
def default_version_unique_id() -> str:
    pass