from datetime import datetime, timedelta

from django.utils import timezone as dj_timezone
from rest_framework.fields import DateTimeField


def as_current_tz(dt: datetime):
    return dt.astimezone(dj_timezone.get_current_timezone())


def utc_now():
    return dj_timezone.now()


def local_now():
    return dj_timezone.localtime(dj_timezone.now())


def local_now_display(fmt='%Y-%m-%d %H:%M:%S'):
    return local_now().strftime(fmt)


def local_now_filename():
    return local_now().strftime('%Y%m%d-%H%M%S')


def local_now_date_display(fmt='%Y-%m-%d'):
    return local_now().strftime(fmt)


def local_zero_hour(fmt='%Y-%m-%d'):
    return datetime.strptime(local_now().strftime(fmt), fmt)


def local_monday():
    zero_hour_time = local_zero_hour()
    return zero_hour_time - timedelta(zero_hour_time.weekday())


def is_date_more_than(d1, d2, threshold='1d'):
    if d1 is None:
        return False
    if d2 is None:
        return True

    kwargs = {}
    if 'd' in threshold:
        kwargs['days'] = int(threshold[:-1])
    elif 'h' in threshold:
        kwargs['hours'] = int(threshold[:-1])
    elif 'm' in threshold:
        kwargs['minutes'] = int(threshold[:-1])
    else:
        raise ValueError('Invalid threshold format')

    delta = dj_timezone.timedelta(**kwargs)
    return d1 - d2 > delta


def contains_time_period(time_periods, ctime=None):
    """
    time_periods: [{"id": 1, "value": "00:00~07:30、10:00~13:00"}, {"id": 2, "value": "00:00~00:00"}]
    """
    if not time_periods:
        return None

    if ctime is None:
        ctime = local_now()
    current_time = ctime.strftime('%H:%M')
    today_time_period = next(filter(lambda x: str(x['id']) == local_now().strftime("%w"), time_periods))
    today_time_period = today_time_period['value']
    if not today_time_period:
        return False

    for time in today_time_period.split('、'):
        start, end = time.split('~')
        end = "24:00" if end == "00:00" else end
        if start <= current_time <= end:
            return True
    return False


_rest_dt_field = DateTimeField()
dt_parser = _rest_dt_field.to_internal_value
dt_formatter = _rest_dt_field.to_representation