######################################################
# To Do: How can we refactor code to make that faster?
######################################################

def func(moderator_ids):
    Post.objects.filter(user__pk__in=moderator_ids) \
    .update(updated_at=timezone.now())

#
######################################################


######################################################
# To Do: What problems can we encounter with? How can you impove the code?
######################################################

# problem #1: what if paypal request fails?
# problem #2: race condition
def withdraw(user_id, amount):
    balance = UserBalance.objects.get(user_id=user_id)

    pp_result = send_request_to_paypal(balance.paypal_id, amount)
    if not pp_result.all_ok:
        raise FokkenPaypal(':(')

    (
        UserBalance.objects.filter(user_id=user_id)
        .update(amount=F('amount') - amount)
    )

#
######################################################


######################################################
# To Do:
# 1. Write a code of model `Webinar`, that contains the fields:
# - title
# - is_published
# - starts_at
#
# 2. Please, write a code of the function `get_nearest_webinar`. The function returns a published webinar that starts in the near future.
# 3. Write a code of the function `count_published_webinars`. That returns a number of published webinars.
# 4. How you could change the code if the count of published webinars is displayed on the really visited page?
#
# P.S.: If you need use additional classes you are welcome.
######################################################


class Webinar(models.Model):
    title = models.TextField()
    is_published = models.BooleanField(default=False)
    starts_at = models.DatetimeField()


# should be Webinar's method but whatever
def get_nearest_webinar():
    return (
        Webinar.objects.filter(is_published=True, starts_at__gt=timezone.now())
        .order_by('starts_at')
        .first()
    )

@lru_cache  # for the really visited page. Or use django cache
def count_published_webinars():
    return Webinar.objects.filter(is_published=True).count()

#
######################################################


######################################################
# Please, add the processing of probably exceptions and logging:
######################################################
#

log = logging.getLogger()

@login_required()
def disable_subscription(request):
    account = get_object_or_404(Account, user=request.user)

    if request.method == 'POST':
        if request.POST.get('do_disable'):
            account.switch_to_free()
            log.info(f'account pk:{account.pk} set free')
            return HttpResponseRedirect(reverse('app:my_account'))

        # I assume if there is no do_disable or do_disable=False that means
        # some one os hacky hacky so who cares

    return render(request, 'theme/disable_subscription.html')

#
######################################################


######################################################
# There is a really visited site. Many uWSGI workers. What problem will you probably encounter?
# What changes may you suggest?
######################################################
#

def increment_views(webinar_id):
    # oh no, race condition! Lets fix it, lol!
    (
        Webinar.objects.filter(pk=webinar_id)
        .update(views_count=F('views_count') + 1)
    )
    #...
#
######################################################