class Subscription(models.Model):

    CHOICES_MOUNTH = (
        ('1', '1 month'),
        ('2', '2 month'),
        ('3', '3 month'),
    )

    user = models.ForeignKey(Patient, on_delete=models.SET_NULL, null = True)
    subscription_date = models.DateTimeField("Дата оформления подписки", default=datetime.now(), db_index=True)
    duration = models.CharField(max_length=12, choices=CHOICES_MOUNTH , default="1 month")
    cost = models.IntegerField('Стоимость услуги')
    subscription_end_date = models.DateTimeField("Конец подписки", default=datetime.now(), db_index=True)
    status = models.BooleanField("Статуc подписки : ", default = False)

    def __str__(self):
        return self.duration

class HistoryBalance(models.Model):
    amount = models.IntegerField('Сумма операции')
    current_amount = models.IntegerField('Сумма текущего счёта')
    write_off = models.BooleanField('Снята ли блокировка с текущей суммы', default=False)
    billing_account = models.ForeignKey(BillingAccount, verbose_name= 'Пользовател', on_delete=models.CASCADE)
    datetime_create = models.DateTimeField('Дата создания операции',default=datetime.now(), db_index=True)


class BillingAccount(models.Model):
    user = models.ForeignKey(Patient, on_delete=models.SET_NULL, null = True)
    datetime_create = models.DateTimeField('Дата создания аккаунта',default=datetime.now(), db_index=True)
    amount = models.IntegerField('Cумма на счету', default=0, null=False)


    def paymant_operation(self, amount):
        history = HistoryBalance.objects.create(
            current_amount = self.amount,
            amount = amount,
            write_off = True,
            billing_account = self
        )
        self.amount = self.amount - amount
        self.save()
    def check_status_amount(pacient_id):
        """Проверка суммы для списания со счёта !"""
        block_amount = Block_amount.objects.filter(write_off = False, billing_account__user = pacient_id)
        return block_amount.exists()

    def block_amount(self, amount):
        """Блокирование суммы для дальнейшего списания"""
        Block_amount.objects.create(billing_account = self, amount = amount, write_off = False)

    def take_away_block_amount(self, id):
        """отмена заблокированной суммы !"""
        block_amount = Block_amount.objects.get(id = id)
        block_amount.write_off = True
        block_amount.save()

    def get_summ_in_account(self):
        return self.amount

class Block_amount(models.Model):
    amount = models.IntegerField('Сумма для блокировки аккаунта')
    write_off = models.BooleanField('Снята ли блокировка с текущей суммы', default=False)
    billing_account = models.ForeignKey(BillingAccount, verbose_name= 'Пользовател с заблокированной суммой', on_delete=models.CASCADE)
    datetime_block = models.DateTimeField('Дата создания аккаунта',default=datetime.now(), db_index=True)

@receiver(post_save, sender=Patient)
def save_or_create_account(sender, instance, created, **kwargs):
    if created:
        BillingAcount.objects.create(user=instance)
    else:
        try:
            instance.billingacount.save()
        except ObjectDoesNotExist:
            BillingAcount.objects.create(user=instance)