text: import copy
  import hashlib
  import json
  import logging
  import string
  from collections import Counter
  from datetime import datetime, time, timedelta
  from decimal import Decimal
  from typing import Any, Dict, List, Union
  
  import dateutil
  import pycountry
  import pytz
  from django.conf import settings
  from django.db import models, transaction
  from django.db.models import (
      Case, Exists, F, Max, OuterRef, Q, Subquery, Sum, Value, When,
  )
  from django.db.models.functions import Coalesce, Greatest
  from django.db.models.signals import post_delete
  from django.dispatch import receiver
  from django.urls import reverse
  from django.utils.crypto import get_random_string
  from django.utils.encoding import escape_uri_path
  from django.utils.formats import date_format
  from django.utils.functional import cached_property
  from django.utils.timezone import make_aware, now
  from django.utils.translation import gettext_lazy as _, pgettext_lazy
  from django_countries.fields import Country
  from django_scopes import ScopedManager, scopes_disabled
  from i18nfield.strings import LazyI18nString
  from jsonfallback.fields import FallbackJSONField
  from phonenumber_field.modelfields import PhoneNumberField
  from phonenumber_field.phonenumber import PhoneNumber
  from phonenumbers import NumberParseException
  
  from pretix.base.banlist import banned
  from pretix.base.decimal import round_decimal
  from pretix.base.email import get_email_context
  from pretix.base.i18n import language
  from pretix.base.models import User
  from pretix.base.reldate import RelativeDateWrapper
  from pretix.base.services.locking import NoLockManager
  from pretix.base.settings import PERSON_NAME_SCHEMES
  from pretix.base.signals import order_gracefully_delete
  
  from ...helpers.countries import CachedCountries, FastCountryField
  from .base import LockModel, LoggedModel
  from .event import Event, SubEvent
  from .items import Item, ItemVariation, Question, QuestionOption, Quota
  
  logger = logging.getLogger(__name__)
  
  
  def generate_secret():
      return get_random_string(length=16, allowed_chars=string.ascii_lowercase + string.digits)
  
  
  def generate_position_secret():
      raise TypeError("Function no longer exists, use secret generators")
  
  
  class Order(LockModel, LoggedModel):
      """
      An order is created when a user clicks 'buy' on his cart. It holds
      several OrderPositions and is connected to a user. It has an
      expiration date: If items run out of capacity, orders which are over
      their expiration date might be canceled.
  
      An order -- like all objects -- has an ID, which is globally unique,
      but also a code, which is shorter and easier to memorize, but only
      unique within a single conference.
  
      :param code: In addition to the ID, which is globally unique, every
                   order has an order code, which is shorter and easier to
                   memorize, but is only unique within a single conference.
      :type code: str
      :param status: The status of this order. One of:
  
          * ``STATUS_PENDING``
          * ``STATUS_PAID``
          * ``STATUS_EXPIRED``
          * ``STATUS_CANCELED``
  
      :param event: The event this order belongs to
      :type event: Event
      :param email: The email of the person who ordered this
      :type email: str
      :param phone: The phone number of the person who ordered this
      :type phone: str
      :param testmode: Whether this is a test mode order
      :type testmode: bool
      :param locale: The locale of this order
      :type locale: str
      :param secret: A secret string that is required to modify the order
      :type secret: str
      :param datetime: The datetime of the order placement
      :type datetime: datetime
      :param expires: The date until this order has to be paid to guarantee the fulfillment
      :type expires: datetime
      :param total: The total amount of the order, including the payment fee
      :type total: decimal.Decimal
      :param comment: An internal comment that will only be visible to staff, and never displayed to the user
      :type comment: str
      :param download_reminder_sent: A field to indicate whether a download reminder has been sent.
      :type download_reminder_sent: boolean
      :param require_approval: If set to ``True``, this order is pending approval by an organizer
      :type require_approval: bool
      :param meta_info: Additional meta information on the order, JSON-encoded.
      :type meta_info: str
      :param sales_channel: Identifier of the sales channel this order was created through.
      :type sales_channel: str
      """
  
      STATUS_PENDING = "n"
      STATUS_PAID = "p"
      STATUS_EXPIRED = "e"
      STATUS_CANCELED = "c"
      STATUS_REFUNDED = "c"  # deprecated
      STATUS_CHOICE = (
          (STATUS_PENDING, _("pending")),
          (STATUS_PAID, _("paid")),
          (STATUS_EXPIRED, _("expired")),
          (STATUS_CANCELED, _("canceled")),
      )
  
      code = models.CharField(
          max_length=16,
          verbose_name=_("Order code"),
          db_index=True
      )
      status = models.CharField(
          max_length=3,
          choices=STATUS_CHOICE,
          verbose_name=_("Status"),
          db_index=True
      )
      testmode = models.BooleanField(default=False)
      event = models.ForeignKey(
          Event,
          verbose_name=_("Event"),
          related_name="orders",
          on_delete=models.CASCADE
      )
      email = models.EmailField(
          null=True, blank=True,
          verbose_name=_('E-mail')
      )
      phone = PhoneNumberField(
          null=True, blank=True,
          verbose_name=_('Phone number'),
      )
      locale = models.CharField(
          null=True, blank=True, max_length=32,
          verbose_name=_('Locale')
      )
      secret = models.CharField(max_length=32, default=generate_secret)
      datetime = models.DateTimeField(
          verbose_name=_("Date"), db_index=True
      )
      cancellation_date = models.DateTimeField(
          null=True, blank=True
      )
      expires = models.DateTimeField(
          verbose_name=_("Expiration date")
      )
      total = models.DecimalField(
          decimal_places=2, max_digits=10,
          verbose_name=_("Total amount")
      )
      comment = models.TextField(
          blank=True, verbose_name=_("Comment"),
          help_text=_("The text entered in this field will not be visible to the user and is available for your "
                      "convenience.")
      )
      checkin_attention = models.BooleanField(
          verbose_name=_('Requires special attention'),
          default=False,
          help_text=_('If you set this, the check-in app will show a visible warning that tickets of this order require '
                      'special attention. This will not show any details or custom message, so you need to brief your '
                      'check-in staff how to handle these cases.')
      )
      expiry_reminder_sent = models.BooleanField(
          default=False
      )
  
      download_reminder_sent = models.BooleanField(
          default=False
      )
      meta_info = models.TextField(
          verbose_name=_("Meta information"),
          null=True, blank=True
      )
      last_modified = models.DateTimeField(
          auto_now=True, db_index=True
      )
      require_approval = models.BooleanField(
          default=False
      )
      sales_channel = models.CharField(max_length=190, default="web")
      email_known_to_work = models.BooleanField(
          default=False,
          verbose_name=_('E-mail address verified')
      )
  
      objects = ScopedManager(organizer='event__organizer')
  
      class Meta:
          verbose_name = _("Order")
          verbose_name_plural = _("Orders")
          ordering = ("-datetime",)
  
      def __str__(self):
          return self.full_code
  
      def gracefully_delete(self, user=None, auth=None):
          from . import GiftCard, GiftCardTransaction, Voucher
  
          if not self.testmode:
              raise TypeError("Only test mode orders can be deleted.")
          self.event.log_action(
              'pretix.event.order.deleted', user=user, auth=auth,
              data={
                  'code': self.code,
              }
          )
  
          order_gracefully_delete.send(self.event, order=self)
  
          if self.status != Order.STATUS_CANCELED:
              for position in self.positions.all():
                  if position.voucher:
                      Voucher.objects.filter(pk=position.voucher.pk).update(redeemed=Greatest(0, F('redeemed') - 1))
  
          GiftCardTransaction.objects.filter(payment__in=self.payments.all()).update(payment=None)
          GiftCardTransaction.objects.filter(refund__in=self.refunds.all()).update(refund=None)
          GiftCardTransaction.objects.filter(order=self).update(order=None)
          GiftCard.objects.filter(issued_in__in=self.positions.all()).update(issued_in=None)
          OrderPosition.all.filter(order=self, addon_to__isnull=False).delete()
          OrderPosition.all.filter(order=self).delete()
          OrderFee.all.filter(order=self).delete()
          self.refunds.all().delete()
          self.payments.all().delete()
          self.event.cache.delete('complain_testmode_orders')
          self.delete()
  
      def email_confirm_hash(self):
          return hashlib.sha256(settings.SECRET_KEY.encode() + self.secret.encode()).hexdigest()[:9]
  
      @property
      def fees(self):
          """
          Related manager for all non-canceled fees. Use ``all_fees`` instead if you want
          canceled positions as well.
          """
          return self.all_fees(manager='objects')
  
      @cached_property
      @scopes_disabled()
      def count_positions(self):
          if hasattr(self, 'pcnt'):
              return self.pcnt or 0
          return self.positions.count()
  
      @property
      def positions(self):
          """
          Related manager for all non-canceled positions. Use ``all_positions`` instead if you want
          canceled positions as well.
          """
          return self.all_positions(manager='objects')
  
      @cached_property
      def meta_info_data(self):
          if not self.meta_info:
              return {}
          try:
              return json.loads(self.meta_info)
          except TypeError:
              return None
  
      @property
      @scopes_disabled()
      def payment_refund_sum(self):
          payment_sum = self.payments.filter(
              state__in=(OrderPayment.PAYMENT_STATE_CONFIRMED, OrderPayment.PAYMENT_STATE_REFUNDED)
          ).aggregate(s=Sum('amount'))['s'] or Decimal('0.00')
          refund_sum = self.refunds.filter(
              state__in=(OrderRefund.REFUND_STATE_DONE, OrderRefund.REFUND_STATE_TRANSIT,
                         OrderRefund.REFUND_STATE_CREATED)
          ).aggregate(s=Sum('amount'))['s'] or Decimal('0.00')
          return payment_sum - refund_sum
  
      @property
      @scopes_disabled()
      def pending_sum(self):
          total = self.total
          if self.status == Order.STATUS_CANCELED:
              total = Decimal('0.00')
          payment_sum = self.payments.filter(
              state__in=(OrderPayment.PAYMENT_STATE_CONFIRMED, OrderPayment.PAYMENT_STATE_REFUNDED)
          ).aggregate(s=Sum('amount'))['s'] or Decimal('0.00')
          refund_sum = self.refunds.filter(
              state__in=(OrderRefund.REFUND_STATE_DONE, OrderRefund.REFUND_STATE_TRANSIT,
                         OrderRefund.REFUND_STATE_CREATED)
          ).aggregate(s=Sum('amount'))['s'] or Decimal('0.00')
          return total - payment_sum + refund_sum
  
      @classmethod
      def annotate_overpayments(cls, qs, results=True, refunds=True, sums=False):
          payment_sum = OrderPayment.objects.filter(
              state__in=(OrderPayment.PAYMENT_STATE_CONFIRMED, OrderPayment.PAYMENT_STATE_REFUNDED),
              order=OuterRef('pk')
          ).order_by().values('order').annotate(s=Sum('amount')).values('s')
          refund_sum = OrderRefund.objects.filter(
              state__in=(OrderRefund.REFUND_STATE_DONE, OrderRefund.REFUND_STATE_TRANSIT,
                         OrderRefund.REFUND_STATE_CREATED),
              order=OuterRef('pk')
          ).order_by().values('order').annotate(s=Sum('amount')).values('s')
          external_refund = OrderRefund.objects.filter(
              state=OrderRefund.REFUND_STATE_EXTERNAL,
              order=OuterRef('pk')
          )
          pending_refund = OrderRefund.objects.filter(
              state__in=(OrderRefund.REFUND_STATE_CREATED, OrderRefund.REFUND_STATE_TRANSIT),
              order=OuterRef('pk')
          )
          payment_sum_sq = Subquery(payment_sum, output_field=models.DecimalField(decimal_places=2, max_digits=10))
          refund_sum_sq = Subquery(refund_sum, output_field=models.DecimalField(decimal_places=2, max_digits=10))
          if sums:
              qs = qs.annotate(
                  payment_sum=payment_sum_sq,
                  refund_sum=refund_sum_sq,
              )
              qs = qs.annotate(
                  computed_payment_refund_sum=Coalesce(payment_sum_sq, 0) - Coalesce(refund_sum_sq, 0),
              )
  
          qs = qs.annotate(
              pending_sum_t=F('total') - Coalesce(payment_sum_sq, 0) + Coalesce(refund_sum_sq, 0),
              pending_sum_rc=-1 * Coalesce(payment_sum_sq, 0) + Coalesce(refund_sum_sq, 0),
          )
          if refunds:
              qs = qs.annotate(
                  has_external_refund=Exists(external_refund),
                  has_pending_refund=Exists(pending_refund),
              )
          if results:
              qs = qs.annotate(
                  is_overpaid=Case(
                      When(~Q(status=Order.STATUS_CANCELED) & Q(pending_sum_t__lt=-1e-8),
                           then=Value('1')),
                      When(Q(status=Order.STATUS_CANCELED) & Q(pending_sum_rc__lt=-1e-8),
                           then=Value('1')),
                      default=Value('0'),
                      output_field=models.IntegerField()
                  ),
                  is_pending_with_full_payment=Case(
                      When(Q(status__in=(Order.STATUS_EXPIRED, Order.STATUS_PENDING)) & Q(pending_sum_t__lte=1e-8)
                           & Q(require_approval=False),
                           then=Value('1')),
                      default=Value('0'),
                      output_field=models.IntegerField()
                  ),
                  is_underpaid=Case(
                      When(Q(status=Order.STATUS_PAID) & Q(pending_sum_t__gt=1e-8),
                           then=Value('1')),
                      default=Value('0'),
                      output_field=models.IntegerField()
                  )
              )
          return qs
  
      @property
      def full_code(self):
          """
          An order code which is unique among all events of a single organizer,
          built by concatenating the event slug and the order code.
          """
          return '{event}-{code}'.format(event=self.event.slug.upper(), code=self.code)
  
      @property
      def changable(self):
          return self.status in (Order.STATUS_PAID, Order.STATUS_PENDING)
  
      def save(self, **kwargs):
          if 'update_fields' in kwargs and 'last_modified' not in kwargs['update_fields']:
              kwargs['update_fields'] = list(kwargs['update_fields']) + ['last_modified']
          if not self.code:
              self.assign_code()
          if not self.datetime:
              self.datetime = now()
          if not self.expires:
              self.set_expires()
          super().save(**kwargs)
  
      def touch(self):
          self.save(update_fields=['last_modified'])
  
      def set_expires(self, now_dt=None, subevents=None):
          now_dt = now_dt or now()
          tz = pytz.timezone(self.event.settings.timezone)
          mode = self.event.settings.get('payment_term_mode')
          if mode == 'days':
              exp_by_date = now_dt.astimezone(tz) + timedelta(days=self.event.settings.get('payment_term_days', as_type=int))
              exp_by_date = exp_by_date.astimezone(tz).replace(hour=23, minute=59, second=59, microsecond=0)
              if self.event.settings.get('payment_term_weekdays'):
                  if exp_by_date.weekday() == 5:
                      exp_by_date += timedelta(days=2)
                  elif exp_by_date.weekday() == 6:
                      exp_by_date += timedelta(days=1)
          elif mode == 'minutes':
              exp_by_date = now_dt.astimezone(tz) + timedelta(minutes=self.event.settings.get('payment_term_minutes', as_type=int))
          else:
              raise ValueError("'payment_term_mode' has an invalid value '{}'.".format(mode))
  
          self.expires = exp_by_date
  
          term_last = self.event.settings.get('payment_term_last', as_type=RelativeDateWrapper)
          if term_last:
              if self.event.has_subevents and subevents:
                  terms = [
                      term_last.datetime(se).date()
                      for se in subevents
                  ]
                  if not terms:
                      return
                  term_last = min(terms)
              else:
                  term_last = term_last.datetime(self.event).date()
              term_last = make_aware(datetime.combine(
                  term_last,
                  time(hour=23, minute=59, second=59)
              ), tz)
              if term_last < self.expires:
                  self.expires = term_last
  
      @cached_property
      def tax_total(self):
          return (self.positions.aggregate(s=Sum('tax_value'))['s'] or 0) + (self.fees.aggregate(s=Sum('tax_value'))['s'] or 0)
  
      @property
      def net_total(self):
          return self.total - self.tax_total
  
      def cancel_allowed(self):
          return (
              self.status in (Order.STATUS_PENDING, Order.STATUS_PAID, Order.STATUS_EXPIRED) and self.count_positions
          )
  
      @cached_property
      def user_change_deadline(self):
          until = self.event.settings.get('change_allow_user_until', as_type=RelativeDateWrapper)
          if until:
              if self.event.has_subevents:
                  terms = [
                      until.datetime(se)
                      for se in self.event.subevents.filter(id__in=self.positions.values_list('subevent', flat=True))
                  ]
                  return min(terms) if terms else None
              else:
                  return until.datetime(self.event)
  
      @cached_property
      def user_cancel_deadline(self):
          if self.status == Order.STATUS_PAID and self.total != Decimal('0.00'):
              until = self.event.settings.get('cancel_allow_user_paid_until', as_type=RelativeDateWrapper)
          else:
              until = self.event.settings.get('cancel_allow_user_until', as_type=RelativeDateWrapper)
          if until:
              if self.event.has_subevents:
                  terms = [
                      until.datetime(se)
                      for se in self.event.subevents.filter(id__in=self.positions.values_list('subevent', flat=True))
                  ]
                  return min(terms) if terms else None
              else:
                  return until.datetime(self.event)
  
      @cached_property
      def user_cancel_fee(self):
          fee = Decimal('0.00')
          if self.event.settings.cancel_allow_user_paid_keep_fees:
              fee += self.fees.filter(
                  fee_type__in=(OrderFee.FEE_TYPE_PAYMENT, OrderFee.FEE_TYPE_SHIPPING, OrderFee.FEE_TYPE_SERVICE,
                                OrderFee.FEE_TYPE_CANCELLATION)
              ).aggregate(
                  s=Sum('value')
              )['s'] or 0
          if self.event.settings.cancel_allow_user_paid_keep_percentage:
              fee += self.event.settings.cancel_allow_user_paid_keep_percentage / Decimal('100.0') * (self.total - fee)
          if self.event.settings.cancel_allow_user_paid_keep:
              fee += self.event.settings.cancel_allow_user_paid_keep
          return round_decimal(fee, self.event.currency)
  
      @property
      @scopes_disabled()
      def user_change_allowed(self) -> bool:
          """
          Returns whether or not this order can be canceled by the user.
          """
          from .checkin import Checkin
  
          if self.status not in (Order.STATUS_PENDING, Order.STATUS_PAID) or not self.count_positions:
              return False
  
          if self.cancellation_requests.exists():
              return False
  
          if self.require_approval:
              return False
  
          positions = list(
              self.positions.all().annotate(
                  has_variations=Exists(ItemVariation.objects.filter(item_id=OuterRef('item_id'))),
                  has_checkin=Exists(Checkin.objects.filter(position_id=OuterRef('pk')))
              ).select_related('item').prefetch_related('issued_gift_cards')
          )
          cancelable = all([op.item.allow_cancel and not op.has_checkin for op in positions])
          if not cancelable or not positions:
              return False
          for op in positions:
              if op.issued_gift_cards.all():
                  return False
          if self.user_change_deadline and now() > self.user_change_deadline:
              return False
  
          return self.event.settings.change_allow_user_variation and any([op.has_variations for op in positions])
  
      @property
      @scopes_disabled()
      def user_cancel_allowed(self) -> bool:
          """
          Returns whether or not this order can be canceled by the user.
          """
          from .checkin import Checkin
  
          if self.cancellation_requests.exists() or not self.cancel_allowed():
              return False
          positions = list(
              self.positions.all().annotate(
                  has_checkin=Exists(Checkin.objects.filter(position_id=OuterRef('pk')))
              ).select_related('item').prefetch_related('issued_gift_cards')
          )
          cancelable = all([op.item.allow_cancel and not op.has_checkin for op in positions])
          if not cancelable or not positions:
              return False
          for op in positions:
              for gc in op.issued_gift_cards.all():
                  if gc.value != op.price:
                      return False
          if self.user_cancel_deadline and now() > self.user_cancel_deadline:
              return False
          if self.status == Order.STATUS_PENDING:
              return self.event.settings.cancel_allow_user
          elif self.status == Order.STATUS_PAID:
              if self.total == Decimal('0.00'):
                  return self.event.settings.cancel_allow_user
              return self.event.settings.cancel_allow_user_paid
          return False
  
      def propose_auto_refunds(self, amount: Decimal, payments: list=None):
          # Algorithm to choose which payments are to be refunded to create the least hassle
          payments = payments or self.payments.filter(state=OrderPayment.PAYMENT_STATE_CONFIRMED)
          for p in payments:
              if p.payment_provider:
                  p.full_refund_possible = p.payment_provider.payment_refund_supported(p)
                  p.partial_refund_possible = p.payment_provider.payment_partial_refund_supported(p)
                  p.propose_refund = Decimal('0.00')
                  p.available_amount = p.amount - p.refunded_amount
              else:
                  p.full_refund_possible = False
                  p.partial_refund_possible = False
                  p.propose_refund = Decimal('0.00')
                  p.available_amount = Decimal('0.00')
  
          unused_payments = set(p for p in payments if p.full_refund_possible or p.partial_refund_possible)
          to_refund = amount
          proposals = {}
  
          while to_refund and unused_payments:
              bigger = sorted([
                  p for p in unused_payments
                  if p.available_amount > to_refund
                  and p.partial_refund_possible
              ], key=lambda p: p.available_amount)
              same = [
                  p for p in unused_payments
                  if p.available_amount == to_refund
                  and (p.full_refund_possible or p.partial_refund_possible)
              ]
              smaller = sorted([
                  p for p in unused_payments
                  if p.available_amount < to_refund
                  and (p.full_refund_possible or p.partial_refund_possible)
              ], key=lambda p: p.available_amount, reverse=True)
              if same:
                  payment = same[0]
                  proposals[payment] = payment.available_amount
                  to_refund -= payment.available_amount
                  unused_payments.remove(payment)
              elif bigger:
                  payment = bigger[0]
                  proposals[payment] = to_refund
                  to_refund -= to_refund
                  unused_payments.remove(payment)
              elif smaller:
                  payment = smaller[0]
                  proposals[payment] = payment.available_amount
                  to_refund -= payment.available_amount
                  unused_payments.remove(payment)
              else:
                  break
          return proposals
  
      @staticmethod
      def normalize_code(code, is_fallback=False):
          d = {
              '2': 'Z',
              '4': 'A',
              '5': 'S',
              '6': 'G',
          }
          if is_fallback:
              d['8'] = 'B'
              # 8 has been removed from the character set only in 2021, which means there are a lot of order codes
              # with an 8 in it around. We only want to replace this when this is used in a fallback.
          tr = str.maketrans(d)
          return code.upper().translate(tr)
  
      def assign_code(self):
          # This omits some character pairs completely because they are hard to read even on screens (1/I and O/0)
          # and includes only one of two characters for some pairs because they are sometimes hard to distinguish in
          # handwriting (2/Z, 4/A, 5/S, 6/G, 8/B). This allows for better detection e.g. in incoming wire transfers that
          # might include OCR'd handwritten text
          charset = list('ABCDEFGHJKLMNPQRSTUVWXYZ379')
          iteration = 0
          length = settings.ENTROPY['order_code']
          while True:
              code = get_random_string(length=length, allowed_chars=charset)
              iteration += 1
  
              if banned(code):
                  continue
  
              if self.testmode:
                  # Subtle way to recognize test orders while debugging: They all contain a 0 at the second place,
                  # even though zeros are not used outside test mode.
                  code = code[0] + "0" + code[2:]
  
              if not Order.objects.filter(event__organizer=self.event.organizer, code=code).exists():
                  self.code = code
                  return
  
              if iteration > 20:
                  # Safeguard: If we don't find an unused and non-banlisted code within 20 iterations, we increase
                  # the length.
                  length += 1
                  iteration = 0
  
      @property
      def can_modify_answers(self) -> bool:
          """
          ``True`` if the user can change the question answers / attendee names that are
          related to the order. This checks order status and modification deadlines. It also
          returns ``False`` if there are no questions that can be answered.
          """
          from .checkin import Checkin
  
          if self.status not in (Order.STATUS_PENDING, Order.STATUS_PAID, Order.STATUS_EXPIRED):
              return False
  
          modify_deadline = self.event.settings.get('last_order_modification_date', as_type=RelativeDateWrapper)
          if self.event.has_subevents and modify_deadline:
              dates = [
                  modify_deadline.datetime(se)
                  for se in self.event.subevents.filter(id__in=self.positions.values_list('subevent', flat=True))
              ]
              modify_deadline = min(dates) if dates else None
          elif modify_deadline:
              modify_deadline = modify_deadline.datetime(self.event)
  
          if modify_deadline is not None and now() > modify_deadline:
              return False
  
          positions = list(
              self.positions.all().annotate(
                  has_checkin=Exists(Checkin.objects.filter(position_id=OuterRef('pk')))
              ).select_related('item').prefetch_related('item__questions')
          )
          if not self.event.settings.allow_modifications_after_checkin:
              for cp in positions:
                  if cp.has_checkin:
                      return False
  
          if self.event.settings.get('invoice_address_asked', as_type=bool):
              return True
          ask_names = self.event.settings.get('attendee_names_asked', as_type=bool)
          for cp in positions:
              if (cp.item.admission and ask_names) or cp.item.questions.all():
                  return True
  
          return False  # nothing there to modify
  
      @property
      def is_expired_by_time(self):
          return (
              self.status == Order.STATUS_PENDING and self.expires < now()
              and not self.event.settings.get('payment_term_expire_automatically')
          )
  
      @property
      def ticket_download_date(self):
          """
          Returns the first date the tickets for this order can be downloaded or ``None`` if there is no
          restriction.
          """
          dl_date = self.event.settings.get('ticket_download_date', as_type=RelativeDateWrapper)
          if dl_date:
              if self.event.has_subevents:
                  dates = [
                      dl_date.datetime(se)
                      for se in self.event.subevents.filter(id__in=self.positions.values_list('subevent', flat=True))
                  ]
                  dl_date = min(dates) if dates else None
              else:
                  dl_date = dl_date.datetime(self.event)
          return dl_date
  
      @property
      def ticket_download_available(self):
          return self.event.settings.ticket_download and (
              self.event.settings.ticket_download_date is None
              or now() > self.ticket_download_date
          ) and (
              self.status == Order.STATUS_PAID
              or (
                  (self.event.settings.ticket_download_pending or self.total == Decimal("0.00")) and
                  self.status == Order.STATUS_PENDING and
                  not self.require_approval
              )
          )
  
      @property
      def payment_term_last(self):
          tz = pytz.timezone(self.event.settings.timezone)
          term_last = self.event.settings.get('payment_term_last', as_type=RelativeDateWrapper)
          if term_last:
              if self.event.has_subevents:
                  terms = [
                      term_last.datetime(se).date()
                      for se in self.event.subevents.filter(id__in=self.positions.values_list('subevent', flat=True))
                  ]
                  if terms:
                      term_last = min(terms)
                  else:
                      term_last = None
              else:
                  term_last = term_last.datetime(self.event).date()
              term_last = make_aware(datetime.combine(
                  term_last,
                  time(hour=23, minute=59, second=59)
              ), tz)
          return term_last
  
      def _can_be_paid(self, count_waitinglist=True, ignore_date=False, force=False) -> Union[bool, str]:
          error_messages = {
              'late_lastdate': _("The payment can not be accepted as the last date of payments configured in the "
                                 "payment settings is over."),
              'late': _("The payment can not be accepted as the order is expired and you configured that no late "
                        "payments should be accepted in the payment settings."),
              'require_approval': _('This order is not yet approved by the event organizer.')
          }
          if not force:
              if self.require_approval:
                  return error_messages['require_approval']
              term_last = self.payment_term_last
              if term_last and not ignore_date:
                  if now() > term_last:
                      return error_messages['late_lastdate']
  
          if self.status == self.STATUS_PENDING:
              return True
          if not self.event.settings.get('payment_term_accept_late') and not ignore_date and not force:
              return error_messages['late']
  
          return self._is_still_available(count_waitinglist=count_waitinglist, force=force)
  
      def _is_still_available(self, now_dt: datetime=None, count_waitinglist=True, force=False,
                              check_voucher_usage=False) -> Union[bool, str]:
          error_messages = {
              'unavailable': _('The ordered product "{item}" is no longer available.'),
              'seat_unavailable': _('The seat "{seat}" is no longer available.'),
              'voucher_budget': _('The voucher "{voucher}" no longer has sufficient budget.'),
              'voucher_usages': _('The voucher "{voucher}" has been used in the meantime.'),
          }
          now_dt = now_dt or now()
          positions = self.positions.all().select_related('item', 'variation', 'seat', 'voucher')
          quota_cache = {}
          v_budget = {}
          v_usage = Counter()
          try:
              for i, op in enumerate(positions):
                  if op.seat:
                      if not op.seat.is_available(ignore_orderpos=op):
                          raise Quota.QuotaExceededException(error_messages['seat_unavailable'].format(seat=op.seat))
                  if force:
                      continue
  
                  if op.voucher and op.voucher.budget is not None and op.price_before_voucher is not None:
                      if op.voucher not in v_budget:
                          v_budget[op.voucher] = op.voucher.budget - op.voucher.budget_used()
                      disc = op.price_before_voucher - op.price
                      if disc > v_budget[op.voucher]:
                          raise Quota.QuotaExceededException(error_messages['voucher_budget'].format(
                              voucher=op.voucher.code
                          ))
                      v_budget[op.voucher] -= disc
  
                  if op.voucher and check_voucher_usage:
                      v_usage[op.voucher.pk] += 1
                      if v_usage[op.voucher.pk] + op.voucher.redeemed > op.voucher.max_usages:
                          raise Quota.QuotaExceededException(error_messages['voucher_usages'].format(
                              voucher=op.voucher.code
                          ))
  
                  quotas = list(op.quotas)
                  if len(quotas) == 0:
                      raise Quota.QuotaExceededException(error_messages['unavailable'].format(
                          item=str(op.item) + (' - ' + str(op.variation) if op.variation else '')
                      ))
  
                  for quota in quotas:
                      if quota.id not in quota_cache:
                          quota_cache[quota.id] = quota
                          quota.cached_availability = quota.availability(now_dt, count_waitinglist=count_waitinglist)[1]
                      else:
                          # Use cached version
                          quota = quota_cache[quota.id]
                      if quota.cached_availability is not None:
                          quota.cached_availability -= 1
                          if quota.cached_availability < 0:
                              # This quota is sold out/currently unavailable, so do not sell this at all
                              raise Quota.QuotaExceededException(error_messages['unavailable'].format(
                                  item=str(op.item) + (' - ' + str(op.variation) if op.variation else '')
                              ))
          except Quota.QuotaExceededException as e:
              return str(e)
          return True
  
      def send_mail(self, subject: str, template: Union[str, LazyI18nString],
                    context: Dict[str, Any]=None, log_entry_type: str='pretix.event.order.email.sent',
                    user: User=None, headers: dict=None, sender: str=None, invoices: list=None,
                    auth=None, attach_tickets=False, position: 'OrderPosition'=None, auto_email=True,
                    attach_ical=False):
          """
          Sends an email to the user that placed this order. Basically, this method does two things:
  
          * Call ``pretix.base.services.mail.mail`` with useful values for the ``event``, ``locale``, ``recipient`` and
            ``order`` parameters.
  
          * Create a ``LogEntry`` with the email contents.
  
          :param subject: Subject of the email
          :param template: LazyI18nString or template filename, see ``pretix.base.services.mail.mail`` for more details
          :param context: Dictionary to use for rendering the template
          :param log_entry_type: Key to be used for the log entry
          :param user: Administrative user who triggered this mail to be sent
          :param headers: Dictionary with additional mail headers
          :param sender: Custom email sender.
          :param attach_tickets: Attach tickets of this order, if they are existing and ready to download
          :param attach_ical: Attach relevant ICS files
          :param position: An order position this refers to. If given, no invoices will be attached, the tickets will
                           only be attached for this position and child positions, the link will only point to the
                           position and the attendee email will be used if available.
          """
          from pretix.base.services.mail import (
              SendMailException, TolerantDict, mail, render_mail,
          )
  
          if not self.email:
              return
  
          for k, v in self.event.meta_data.items():
              context['meta_' + k] = v
  
          with language(self.locale, self.event.settings.region):
              recipient = self.email
              if position and position.attendee_email:
                  recipient = position.attendee_email
  
              try:
                  email_content = render_mail(template, context)
                  subject = subject.format_map(TolerantDict(context))
                  mail(
                      recipient, subject, template, context,
                      self.event, self.locale, self, headers=headers, sender=sender,
                      invoices=invoices, attach_tickets=attach_tickets,
                      position=position, auto_email=auto_email, attach_ical=attach_ical
                  )
              except SendMailException:
                  raise
              else:
                  self.log_action(
                      log_entry_type,
                      user=user,
                      auth=auth,
                      data={
                          'subject': subject,
                          'message': email_content,
                          'position': position.positionid if position else None,
                          'recipient': recipient,
                          'invoices': [i.pk for i in invoices] if invoices else [],
                          'attach_tickets': attach_tickets,
                          'attach_ical': attach_ical,
                      }
                  )
  
      def resend_link(self, user=None, auth=None):
          with language(self.locale, self.event.settings.region):
              email_template = self.event.settings.mail_text_resend_link
              email_context = get_email_context(event=self.event, order=self)
              email_subject = _('Your order: %(code)s') % {'code': self.code}
              self.send_mail(
                  email_subject, email_template, email_context,
                  'pretix.event.order.email.resend', user=user, auth=auth,
                  attach_tickets=True,
              )
  
      @property
      def positions_with_tickets(self):
          for op in self.positions.select_related('item'):
              if not op.generate_ticket:
                  continue
              yield op
  
  
  def answerfile_name(instance, filename: str) -> str:
      secret = get_random_string(length=32, allowed_chars=string.ascii_letters + string.digits)
      event = (instance.cartposition if instance.cartposition else instance.orderposition.order).event
      return 'cachedfiles/answers/{org}/{ev}/{secret}.{filename}'.format(
          org=event.organizer.slug,
          ev=event.slug,
          secret=secret,
          filename=escape_uri_path(filename),
      )
  
  
  class QuestionAnswer(models.Model):
      """
      The answer to a Question, connected to an OrderPosition or CartPosition.
  
      :param orderposition: The order position this is related to, or null if this is
                            related to a cart position.
      :type orderposition: OrderPosition
      :param cartposition: The cart position this is related to, or null if this is related
                           to an order position.
      :type cartposition: CartPosition
      :param question: The question this is an answer for
      :type question: Question
      :param answer: The actual answer data
      :type answer: str
      """
      orderposition = models.ForeignKey(
          'OrderPosition', null=True, blank=True,
          related_name='answers', on_delete=models.CASCADE
      )
      cartposition = models.ForeignKey(
          'CartPosition', null=True, blank=True,
          related_name='answers', on_delete=models.CASCADE
      )
      question = models.ForeignKey(
          Question, related_name='answers', on_delete=models.CASCADE
      )
      options = models.ManyToManyField(
          QuestionOption, related_name='answers', blank=True
      )
      answer = models.TextField()
      file = models.FileField(
          null=True, blank=True, upload_to=answerfile_name,
          max_length=255
      )
  
      objects = ScopedManager(organizer='question__event__organizer')
  
      @property
      def backend_file_url(self):
          if self.file:
              if self.orderposition:
                  return reverse('control:event.order.download.answer', kwargs={
                      'code': self.orderposition.order.code,
                      'event': self.orderposition.order.event.slug,
                      'organizer': self.orderposition.order.event.organizer.slug,
                      'answer': self.pk,
                  })
          return ""
  
      @property
      def frontend_file_url(self):
          from pretix.multidomain.urlreverse import eventreverse
  
          if self.file:
              if self.orderposition:
                  url = eventreverse(self.orderposition.order.event, 'presale:event.order.download.answer', kwargs={
                      'order': self.orderposition.order.code,
                      'secret': self.orderposition.order.secret,
                      'answer': self.pk,
                  })
              else:
                  url = eventreverse(self.cartposition.event, 'presale:event.cart.download.answer', kwargs={
                      'answer': self.pk,
                  })
  
              return url
          return ""
  
      @property
      def is_image(self):
          return any(self.file.name.lower().endswith(e) for e in ('.jpg', '.png', '.gif', '.tiff', '.bmp', '.jpeg'))
  
      @property
      def file_name(self):
          return self.file.name.split('.', 1)[-1]
  
      def __str__(self):
          if self.question.type == Question.TYPE_BOOLEAN and self.answer == "True":
              return str(_("Yes"))
          elif self.question.type == Question.TYPE_BOOLEAN and self.answer == "False":
              return str(_("No"))
          elif self.question.type == Question.TYPE_FILE:
              return str(_("<file>"))
          elif self.question.type == Question.TYPE_DATETIME and self.answer:
              try:
                  d = dateutil.parser.parse(self.answer)
                  if self.orderposition:
                      tz = pytz.timezone(self.orderposition.order.event.settings.timezone)
                      d = d.astimezone(tz)
                  return date_format(d, "SHORT_DATETIME_FORMAT")
              except ValueError:
                  return self.answer
          elif self.question.type == Question.TYPE_DATE and self.answer:
              try:
                  d = dateutil.parser.parse(self.answer)
                  return date_format(d, "SHORT_DATE_FORMAT")
              except ValueError:
                  return self.answer
          elif self.question.type == Question.TYPE_TIME and self.answer:
              try:
                  d = dateutil.parser.parse(self.answer)
                  return date_format(d, "TIME_FORMAT")
              except ValueError:
                  return self.answer
          elif self.question.type == Question.TYPE_COUNTRYCODE and self.answer:
              return Country(self.answer).name or self.answer
          elif self.question.type == Question.TYPE_PHONENUMBER and self.answer:
              try:
                  return PhoneNumber.from_string(self.answer).as_international
              except NumberParseException:
                  return self.answer
          else:
              return self.answer
  
      def save(self, *args, **kwargs):
          if self.orderposition and self.cartposition:
              raise ValueError('QuestionAnswer cannot be linked to an order and a cart position at the same time.')
          if self.orderposition:
              self.orderposition.order.touch()
          super().save(*args, **kwargs)
  
      def delete(self, **kwargs):
          if self.orderposition:
              self.orderposition.order.touch()
          super().delete(**kwargs)
  
  
  class AbstractPosition(models.Model):
      """
      A position can either be one line of an order or an item placed in a cart.
  
      :param subevent: The date in the event series, if event series are enabled
      :type subevent: SubEvent
      :param item: The selected item
      :type item: Item
      :param variation: The selected ItemVariation or null, if the item has no variations
      :type variation: ItemVariation
      :param datetime: The datetime this item was put into the cart
      :type datetime: datetime
      :param expires: The date until this item is guaranteed to be reserved
      :type expires: datetime
      :param price: The price of this item
      :type price: decimal.Decimal
      :param attendee_name_parts: The parts of the attendee's name, if entered.
      :type attendee_name_parts: str
      :param attendee_name_cached: The concatenated version of the attendee's name, if entered.
      :type attendee_name_cached: str
      :param attendee_email: The attendee's email, if entered.
      :type attendee_email: str
      :param voucher: A voucher that has been applied to this sale
      :type voucher: Voucher
      :param meta_info: Additional meta information on the position, JSON-encoded.
      :type meta_info: str
      :param seat: Seat, if reserved seating is used.
      :type seat: Seat
      """
      subevent = models.ForeignKey(
          SubEvent,
          null=True, blank=True,
          on_delete=models.PROTECT,
          verbose_name=pgettext_lazy("subevent", "Date"),
      )
      item = models.ForeignKey(
          Item,
          verbose_name=_("Item"),
          on_delete=models.PROTECT
      )
      variation = models.ForeignKey(
          ItemVariation,
          null=True, blank=True,
          verbose_name=_("Variation"),
          on_delete=models.PROTECT
      )
      price_before_voucher = models.DecimalField(
          decimal_places=2, max_digits=10, null=True,
      )
      price = models.DecimalField(
          decimal_places=2, max_digits=10,
          verbose_name=_("Price")
      )
      attendee_name_cached = models.CharField(
          max_length=255,
          verbose_name=_("Attendee name"),
          blank=True, null=True,
          help_text=_("Empty, if this product is not an admission ticket")
      )
      attendee_name_parts = FallbackJSONField(
          blank=True, default=dict
      )
      attendee_email = models.EmailField(
          verbose_name=_("Attendee email"),
          blank=True, null=True,
          help_text=_("Empty, if this product is not an admission ticket")
      )
      voucher = models.ForeignKey(
          'Voucher', null=True, blank=True, on_delete=models.PROTECT
      )
      addon_to = models.ForeignKey(
          'self', null=True, blank=True, on_delete=models.PROTECT, related_name='addons'
      )
      meta_info = models.TextField(
          verbose_name=_("Meta information"),
          null=True, blank=True
      )
      seat = models.ForeignKey(
          'Seat', null=True, blank=True, on_delete=models.PROTECT
      )
  
      company = models.CharField(max_length=255, blank=True, verbose_name=_('Company name'), null=True)
      street = models.TextField(verbose_name=_('Address'), blank=True, null=True)
      zipcode = models.CharField(max_length=30, verbose_name=_('ZIP code'), blank=True, null=True)
      city = models.CharField(max_length=255, verbose_name=_('City'), blank=True, null=True)
      country = FastCountryField(verbose_name=_('Country'), blank=True, blank_label=_('Select country'), null=True)
      state = models.CharField(max_length=255, verbose_name=pgettext_lazy('address', 'State'), blank=True, null=True)
  
      class Meta:
          abstract = True
  
      @property
      def meta_info_data(self):
          if self.meta_info:
              return json.loads(self.meta_info)
          else:
              return {}
  
      @meta_info_data.setter
      def meta_info_data(self, d):
          self.meta_info = json.dumps(d)
  
      def cache_answers(self, all=True):
          """
          Creates two properties on the object.
          (1) answ: a dictionary of question.id → answer string
          (2) questions: a list of Question objects, extended by an 'answer' property
          """
          self.answ = {}
          for a in getattr(self, 'answerlist', self.answers.all()):  # use prefetch_related cache from get_cart
              self.answ[a.question_id] = a
  
          # We need to clone our question objects, otherwise we will override the cached
          # answers of other items in the same cart if the question objects have been
          # selected via prefetch_related
          if not all:
              if hasattr(self.item, 'questions_to_ask'):
                  questions = list(copy.copy(q) for q in self.item.questions_to_ask)
              else:
                  questions = list(copy.copy(q) for q in self.item.questions.filter(ask_during_checkin=False,
                                                                                    hidden=False))
          else:
              questions = list(copy.copy(q) for q in self.item.questions.all())
  
          question_cache = {
              q.pk: q for q in questions
          }
  
          def question_is_visible(parentid, qvals):
              if parentid not in question_cache:
                  return False
              parentq = question_cache[parentid]
              if parentq.dependency_question_id and not question_is_visible(parentq.dependency_question_id, parentq.dependency_values):
                  return False
              if parentid not in self.answ:
                  return False
              return (
                  ('True' in qvals and self.answ[parentid].answer == 'True')
                  or ('False' in qvals and self.answ[parentid].answer == 'False')
                  or (any(qval in [o.identifier for o in self.answ[parentid].options.all()] for qval in qvals))
              )
  
          self.questions = []
          for q in questions:
              if q.id in self.answ:
                  q.answer = self.answ[q.id]
                  q.answer.question = q  # cache object
              else:
                  q.answer = ""
              if not q.dependency_question_id or question_is_visible(q.dependency_question_id, q.dependency_values):
                  self.questions.append(q)
  
      @property
      def net_price(self):
          return self.price - self.tax_value
  
      @property
      def quotas(self):
          return (self.item.quotas.filter(subevent=self.subevent)
                  if self.variation is None
                  else self.variation.quotas.filter(subevent=self.subevent))
  
      def save(self, *args, **kwargs):
          update_fields = kwargs.get('update_fields', [])
          if 'attendee_name_parts' in update_fields:
              update_fields.append('attendee_name_cached')
          self.attendee_name_cached = self.attendee_name
          if self.attendee_name_parts is None:
              self.attendee_name_parts = {}
          super().save(*args, **kwargs)
  
      @property
      def attendee_name(self):
          if not self.attendee_name_parts:
              return None
          if '_legacy' in self.attendee_name_parts:
              return self.attendee_name_parts['_legacy']
          if '_scheme' in self.attendee_name_parts:
              scheme = PERSON_NAME_SCHEMES[self.attendee_name_parts['_scheme']]
          else:
              scheme = PERSON_NAME_SCHEMES[self.event.settings.name_scheme]
          return scheme['concatenation'](self.attendee_name_parts).strip()
  
      @property
      def state_name(self):
          sd = pycountry.subdivisions.get(code='{}-{}'.format(self.country, self.state))
          if sd:
              return sd.name
          return self.state
  
      @property
      def state_for_address(self):
          from pretix.base.settings import COUNTRIES_WITH_STATE_IN_ADDRESS
          if not self.state or str(self.country) not in COUNTRIES_WITH_STATE_IN_ADDRESS:
              return ""
          if COUNTRIES_WITH_STATE_IN_ADDRESS[str(self.country)][1] == 'long':
              return self.state_name
          return self.state
  
      def address_format(self):
          lines = [
              self.attendee_name,
              self.company,
              self.street,
              (self.zipcode or '') + ' ' + (self.city or '') + ' ' + (self.state_for_address or ''),
              self.country.name
          ]
          lines = [r.strip() for r in lines if r]
          return '\n'.join(lines).strip()
  
  
  class OrderPayment(models.Model):
      """
      Represents a payment or payment attempt for an order.
  
  
      :param id: A globally unique ID for this payment
      :type id:
      :param local_id: An ID of this payment, counting from one for every order independently.
      :type local_id: int
      :param state: The state of the payment, one of ``created``, ``pending``, ``confirmed``, ``failed``,
        ``canceled``, or ``refunded``.
      :type state: str
      :param amount: The payment amount
      :type amount: Decimal
      :param order: The order that is paid
      :type order: Order
      :param created: The creation time of this record
      :type created: datetime
      :param payment_date: The completion time of this payment
      :type payment_date: datetime
      :param provider: The payment provider in use
      :type provider: str
      :param info: Provider-specific meta information (in JSON format)
      :type info: str
      :param fee: The ``OrderFee`` object used to track the fee for this order.
      :type fee: pretix.base.models.OrderFee
      """
      PAYMENT_STATE_CREATED = 'created'
      PAYMENT_STATE_PENDING = 'pending'
      PAYMENT_STATE_CONFIRMED = 'confirmed'
      PAYMENT_STATE_FAILED = 'failed'
      PAYMENT_STATE_CANCELED = 'canceled'
      PAYMENT_STATE_REFUNDED = 'refunded'
  
      PAYMENT_STATES = (
          (PAYMENT_STATE_CREATED, pgettext_lazy('payment_state', 'created')),
          (PAYMENT_STATE_PENDING, pgettext_lazy('payment_state', 'pending')),
          (PAYMENT_STATE_CONFIRMED, pgettext_lazy('payment_state', 'confirmed')),
          (PAYMENT_STATE_CANCELED, pgettext_lazy('payment_state', 'canceled')),
          (PAYMENT_STATE_FAILED, pgettext_lazy('payment_state', 'failed')),
          (PAYMENT_STATE_REFUNDED, pgettext_lazy('payment_state', 'refunded')),
      )
      local_id = models.PositiveIntegerField()
      state = models.CharField(
          max_length=190, choices=PAYMENT_STATES
      )
      amount = models.DecimalField(
          decimal_places=2, max_digits=10,
          verbose_name=_("Amount")
      )
      order = models.ForeignKey(
          Order,
          verbose_name=_("Order"),
          related_name='payments',
          on_delete=models.PROTECT
      )
      created = models.DateTimeField(
          auto_now_add=True
      )
      payment_date = models.DateTimeField(
          null=True, blank=True
      )
      provider = models.CharField(
          null=True, blank=True,
          max_length=255,
          verbose_name=_("Payment provider")
      )
      info = models.TextField(
          verbose_name=_("Payment information"),
          null=True, blank=True
      )
      fee = models.ForeignKey(
          'OrderFee',
          null=True, blank=True, related_name='payments', on_delete=models.SET_NULL
      )
      migrated = models.BooleanField(default=False)
  
      objects = ScopedManager(organizer='order__event__organizer')
  
      class Meta:
          ordering = ('local_id',)
  
      def __str__(self):
          return self.full_id
  
      @property
      def info_data(self):
          """
          This property allows convenient access to the data stored in the ``info``
          attribute by automatically encoding and decoding the content as JSON.
          """
          return json.loads(self.info) if self.info else {}
  
      @info_data.setter
      def info_data(self, d):
          self.info = json.dumps(d, sort_keys=True)
  
      @cached_property
      def payment_provider(self):
          """
          Cached access to an instance of the payment provider in use.
          """
          return self.order.event.get_payment_providers(cached=True).get(self.provider)
  
      @transaction.atomic()
      def _mark_paid(self, force, count_waitinglist, user, auth, ignore_date=False, overpaid=False):
          from pretix.base.signals import order_paid
          can_be_paid = self.order._can_be_paid(count_waitinglist=count_waitinglist, ignore_date=ignore_date, force=force)
          if can_be_paid is not True:
              self.order.log_action('pretix.event.order.quotaexceeded', {
                  'message': can_be_paid
              }, user=user, auth=auth)
              raise Quota.QuotaExceededException(can_be_paid)
          self.order.status = Order.STATUS_PAID
          self.order.save(update_fields=['status'])
  
          self.order.log_action('pretix.event.order.paid', {
              'provider': self.provider,
              'info': self.info,
              'date': self.payment_date,
              'force': force
          }, user=user, auth=auth)
  
          if overpaid:
              self.order.log_action('pretix.event.order.overpaid', {}, user=user, auth=auth)
          order_paid.send(self.order.event, order=self.order)
  
      def fail(self, info=None, user=None, auth=None):
          """
          Marks the order as failed and sets info to ``info``, but only if the order is in ``created`` or ``pending``
          state. This is equivalent to setting ``state`` to ``OrderPayment.PAYMENT_STATE_FAILED`` and logging a failure,
          but it adds strong database logging since we do not want to report a failure for an order that has just
          been marked as paid.
          """
          with transaction.atomic():
              locked_instance = OrderPayment.objects.select_for_update().get(pk=self.pk)
              if locked_instance.state not in (OrderPayment.PAYMENT_STATE_CREATED, OrderPayment.PAYMENT_STATE_PENDING):
                  # Race condition detected, this payment is already confirmed
                  logger.info('Failed payment {} but ignored due to likely race condition.'.format(
                      self.full_id,
                  ))
                  return
  
              if isinstance(info, str):
                  locked_instance.info = info
              elif info:
                  locked_instance.info_data = info
              locked_instance.state = OrderPayment.PAYMENT_STATE_FAILED
              locked_instance.save(update_fields=['state', 'info'])
  
          self.refresh_from_db()
          self.order.log_action('pretix.event.order.payment.failed', {
              'local_id': self.local_id,
              'provider': self.provider,
              'info': info,
          }, user=user, auth=auth)
  
      def confirm(self, count_waitinglist=True, send_mail=True, force=False, user=None, auth=None, mail_text='',
                  ignore_date=False, lock=True, payment_date=None):
          """
          Marks the payment as complete. If possible, this also marks the order as paid if no further
          payment is required
  
          :param count_waitinglist: Whether, when calculating quota, people on the waiting list should be taken into
                                    consideration (default: ``True``).
          :type count_waitinglist: boolean
          :param force: Whether this payment should be marked as paid even if no remaining
                        quota is available (default: ``False``).
          :param ignore_date: Whether this order should be marked as paid even when the last date of payments is over.
          :type force: boolean
          :param send_mail: Whether an email should be sent to the user about this event (default: ``True``).
          :type send_mail: boolean
          :param user: The user who performed the change
          :param auth: The API auth token that performed the change
          :param mail_text: Additional text to be included in the email
          :type mail_text: str
          :raises Quota.QuotaExceededException: if the quota is exceeded and ``force`` is ``False``
          """
          from pretix.base.services.invoices import (
              generate_invoice, invoice_qualified,
          )
  
          with transaction.atomic():
              locked_instance = OrderPayment.objects.select_for_update().get(pk=self.pk)
              if locked_instance.state == self.PAYMENT_STATE_CONFIRMED:
                  # Race condition detected, this payment is already confirmed
                  logger.info('Confirmed payment {} but ignored due to likely race condition.'.format(
                      self.full_id,
                  ))
                  return
  
              locked_instance.state = self.PAYMENT_STATE_CONFIRMED
              locked_instance.payment_date = payment_date or now()
              locked_instance.info = self.info  # required for backwards compatibility
              locked_instance.save(update_fields=['state', 'payment_date', 'info'])
  
              # Do a cheap manual "refresh from db" on non-complex fields
              for field in self._meta.concrete_fields:
                  if not field.is_relation:
                      setattr(self, field.attname, getattr(locked_instance, field.attname))
  
          self.refresh_from_db()
  
          self.order.log_action('pretix.event.order.payment.confirmed', {
              'local_id': self.local_id,
              'provider': self.provider,
          }, user=user, auth=auth)
  
          if self.order.status in (Order.STATUS_PAID, Order.STATUS_CANCELED):
              logger.info('Confirmed payment {} but order is in status {}.'.format(self.full_id, self.order.status))
              return
  
          payment_sum = self.order.payments.filter(
              state__in=(self.PAYMENT_STATE_CONFIRMED, self.PAYMENT_STATE_REFUNDED)
          ).aggregate(s=Sum('amount'))['s'] or Decimal('0.00')
          refund_sum = self.order.refunds.filter(
              state__in=(OrderRefund.REFUND_STATE_DONE, OrderRefund.REFUND_STATE_TRANSIT,
                         OrderRefund.REFUND_STATE_CREATED)
          ).aggregate(s=Sum('amount'))['s'] or Decimal('0.00')
          if payment_sum - refund_sum < self.order.total:
              logger.info('Confirmed payment {} but payment sum is {} and refund sum is {}.'.format(
                  self.full_id, payment_sum, refund_sum
              ))
              return
  
          if (self.order.status == Order.STATUS_PENDING and self.order.expires > now() + timedelta(hours=12)) or not lock:
              # Performance optimization. In this case, there's really no reason to lock everything and an atomic
              # database transaction is more than enough.
              lockfn = NoLockManager
          else:
              lockfn = self.order.event.lock
  
          with lockfn():
              self._mark_paid(force, count_waitinglist, user, auth, overpaid=payment_sum - refund_sum > self.order.total,
                              ignore_date=ignore_date)
  
          invoice = None
          if invoice_qualified(self.order):
              invoices = self.order.invoices.filter(is_cancellation=False).count()
              cancellations = self.order.invoices.filter(is_cancellation=True).count()
              gen_invoice = (
                  (invoices == 0 and self.order.event.settings.get('invoice_generate') in ('True', 'paid')) or
                  0 < invoices <= cancellations
              )
              if gen_invoice:
                  invoice = generate_invoice(
                      self.order,
                      trigger_pdf=not send_mail or not self.order.event.settings.invoice_email_attachment
                  )
  
          if send_mail and self.order.sales_channel in self.order.event.settings.mail_sales_channel_placed_paid:
              self._send_paid_mail(invoice, user, mail_text)
              if self.order.event.settings.mail_send_order_paid_attendee:
                  for p in self.order.positions.all():
                      if p.addon_to_id is None and p.attendee_email and p.attendee_email != self.order.email:
                          self._send_paid_mail_attendee(p, user)
  
      def _send_paid_mail_attendee(self, position, user):
          from pretix.base.services.mail import SendMailException
  
          with language(self.order.locale, self.order.event.settings.region):
              email_template = self.order.event.settings.mail_text_order_paid_attendee
              email_context = get_email_context(event=self.order.event, order=self.order, position=position)
              email_subject = _('Event registration confirmed: %(code)s') % {'code': self.order.code}
              try:
                  self.order.send_mail(
                      email_subject, email_template, email_context,
                      'pretix.event.order.email.order_paid', user,
                      invoices=[], position=position,
                      attach_tickets=True,
                      attach_ical=self.order.event.settings.mail_attach_ical
                  )
              except SendMailException:
                  logger.exception('Order paid email could not be sent')
  
      def _send_paid_mail(self, invoice, user, mail_text):
          from pretix.base.services.mail import SendMailException
  
          with language(self.order.locale, self.order.event.settings.region):
              email_template = self.order.event.settings.mail_text_order_paid
              email_context = get_email_context(event=self.order.event, order=self.order, payment_info=mail_text)
              email_subject = _('Payment received for your order: %(code)s') % {'code': self.order.code}
              try:
                  self.order.send_mail(
                      email_subject, email_template, email_context,
                      'pretix.event.order.email.order_paid', user,
                      invoices=[invoice] if invoice and self.order.event.settings.invoice_email_attachment else [],
                      attach_tickets=True,
                      attach_ical=self.order.event.settings.mail_attach_ical
                  )
              except SendMailException:
                  logger.exception('Order paid email could not be sent')
  
      @property
      def refunded_amount(self):
          """
          The sum of all refund amounts in ``done``, ``transit``, or ``created`` states associated
          with this payment.
          """
          return self.refunds.filter(
              state__in=(OrderRefund.REFUND_STATE_DONE, OrderRefund.REFUND_STATE_TRANSIT,
                         OrderRefund.REFUND_STATE_CREATED)
          ).aggregate(s=Sum('amount'))['s'] or Decimal('0.00')
  
      @property
      def full_id(self):
          """
          The full human-readable ID of this payment, constructed by the order code and the ``local_id``
          field with ``-P-`` in between.
          :return:
          """
          return '{}-P-{}'.format(self.order.code, self.local_id)
  
      def save(self, *args, **kwargs):
          if not self.local_id:
              self.local_id = (self.order.payments.aggregate(m=Max('local_id'))['m'] or 0) + 1
          super().save(*args, **kwargs)
  
      def create_external_refund(self, amount=None, execution_date=None, info='{}'):
          """
          This should be called to create an OrderRefund object when a refund has triggered
          by an external source, e.g. when a credit card payment has been refunded by the
          credit card provider.
  
          :param amount: Amount to refund. If not given, the full payment amount will be used.
          :type amount: Decimal
          :param execution_date: Date of the refund. Defaults to the current time.
          :type execution_date: datetime
          :param info: Additional information, defaults to ``"{}"``.
          :type info: str
          :return: OrderRefund
          """
          r = self.order.refunds.create(
              state=OrderRefund.REFUND_STATE_EXTERNAL,
              source=OrderRefund.REFUND_SOURCE_EXTERNAL,
              amount=amount if amount is not None else self.amount,
              order=self.order,
              payment=self,
              execution_date=execution_date or now(),
              provider=self.provider,
              info=info
          )
          self.order.log_action('pretix.event.order.refund.created.externally', {
              'local_id': r.local_id,
              'provider': r.provider,
          })
  
          if self.order.pending_sum + r.amount == Decimal('0.00'):
              self.refund.done()
  
          return r
  
  
  class OrderRefund(models.Model):
      """
      Represents a refund or refund attempt for an order.
  
      :param id: A globally unique ID for this refund
      :type id:
      :param local_id: An ID of this refund, counting from one for every order independently.
      :type local_id: int
      :param state: The state of the refund, one of ``created``, ``transit``, ``external``, ``canceled``,
        ``failed``, or ``done``.
      :type state: str
      :param source: How this refund was started, one of ``buyer``, ``admin``, or ``external``.
      :param amount: The refund amount
      :type amount: Decimal
      :param order: The order that is refunded
      :type order: Order
      :param created: The creation time of this record
      :type created: datetime
      :param execution_date: The completion time of this refund
      :type execution_date: datetime
      :param provider: The payment provider in use
      :type provider: str
      :param info: Provider-specific meta information in JSON format
      :type info: dict
      """
      # REFUND_STATE_REQUESTED = 'requested'
      # REFUND_STATE_APPROVED = 'approved'
      REFUND_STATE_EXTERNAL = 'external'
      REFUND_STATE_TRANSIT = 'transit'
      REFUND_STATE_DONE = 'done'
      # REFUND_STATE_REJECTED = 'rejected'
      REFUND_STATE_CANCELED = 'canceled'
      REFUND_STATE_CREATED = 'created'
      REFUND_STATE_FAILED = 'failed'
  
      REFUND_STATES = (
          # (REFUND_STATE_REQUESTED, pgettext_lazy('refund_state', 'requested')),
          # (REFUND_STATE_APPROVED, pgettext_lazy('refund_state', 'approved')),
          (REFUND_STATE_EXTERNAL, pgettext_lazy('refund_state', 'started externally')),
          (REFUND_STATE_CREATED, pgettext_lazy('refund_state', 'created')),
          (REFUND_STATE_TRANSIT, pgettext_lazy('refund_state', 'in transit')),
          (REFUND_STATE_DONE, pgettext_lazy('refund_state', 'done')),
          (REFUND_STATE_FAILED, pgettext_lazy('refund_state', 'failed')),
          # (REFUND_STATE_REJECTED, pgettext_lazy('refund_state', 'rejected')),
          (REFUND_STATE_CANCELED, pgettext_lazy('refund_state', 'canceled')),
      )
  
      REFUND_SOURCE_BUYER = 'buyer'
      REFUND_SOURCE_ADMIN = 'admin'
      REFUND_SOURCE_EXTERNAL = 'external'
  
      REFUND_SOURCES = (
          (REFUND_SOURCE_ADMIN, pgettext_lazy('refund_source', 'Organizer')),
          (REFUND_SOURCE_BUYER, pgettext_lazy('refund_source', 'Customer')),
          (REFUND_SOURCE_EXTERNAL, pgettext_lazy('refund_source', 'External')),
      )
  
      local_id = models.PositiveIntegerField()
      state = models.CharField(
          max_length=190, choices=REFUND_STATES
      )
      source = models.CharField(
          max_length=190, choices=REFUND_SOURCES
      )
      amount = models.DecimalField(
          decimal_places=2, max_digits=10,
          verbose_name=_("Amount")
      )
      order = models.ForeignKey(
          Order,
          verbose_name=_("Order"),
          related_name='refunds',
          on_delete=models.PROTECT
      )
      payment = models.ForeignKey(
          OrderPayment,
          null=True, blank=True,
          related_name='refunds',
          on_delete=models.PROTECT
      )
      created = models.DateTimeField(
          auto_now_add=True
      )
      execution_date = models.DateTimeField(
          null=True, blank=True
      )
      provider = models.CharField(
          null=True, blank=True,
          max_length=255,
          verbose_name=_("Payment provider")
      )
      comment = models.TextField(
          verbose_name=_("Refund reason"),
          help_text=_('May be shown to the end user or used e.g. as part of a payment reference.'),
          null=True, blank=True
      )
      info = models.TextField(
          verbose_name=_("Payment information"),
          null=True, blank=True
      )
  
      objects = ScopedManager(organizer='order__event__organizer')
  
      class Meta:
          ordering = ('local_id',)
  
      def __str__(self):
          return self.full_id
  
      @property
      def info_data(self):
          """
          This property allows convenient access to the data stored in the ``info``
          attribute by automatically encoding and decoding the content as JSON.
          """
          return json.loads(self.info) if self.info else {}
  
      @info_data.setter
      def info_data(self, d):
          self.info = json.dumps(d, sort_keys=True)
  
      @cached_property
      def payment_provider(self):
          """
          Cached access to an instance of the payment provider in use.
          """
          return self.order.event.get_payment_providers().get(self.provider)
  
      @transaction.atomic
      def done(self, user=None, auth=None):
          """
          Marks the refund as complete. This does not modify the state of the order.
  
          :param user: The user who performed the change
          :param auth: The API auth token that performed the change
          """
          self.state = self.REFUND_STATE_DONE
          self.execution_date = self.execution_date or now()
          self.save()
  
          self.order.log_action('pretix.event.order.refund.done', {
              'local_id': self.local_id,
              'provider': self.provider,
          }, user=user, auth=auth)
  
          if self.payment and self.payment.refunded_amount >= self.payment.amount:
              self.payment.state = OrderPayment.PAYMENT_STATE_REFUNDED
              self.payment.save(update_fields=['state'])
  
      @property
      def full_id(self):
          """
          The full human-readable ID of this refund, constructed by the order code and the ``local_id``
          field with ``-R-`` in between.
          :return:
          """
          return '{}-R-{}'.format(self.order.code, self.local_id)
  
      def save(self, *args, **kwargs):
          if not self.local_id:
              self.local_id = (self.order.refunds.aggregate(m=Max('local_id'))['m'] or 0) + 1
          super().save(*args, **kwargs)
  
  
  class ActivePositionManager(ScopedManager(organizer='order__event__organizer').__class__):
      def get_queryset(self):
          return super().get_queryset().filter(canceled=False)
  
  
  class OrderFee(models.Model):
      """
      An OrderFee object represents a fee that is added to the order total independently of
      the actual positions. This might for example be a payment or a shipping fee.
  
      The default ``OrderFee.objects`` manager only contains fees that are not ``canceled``. If
      you ant all objects, you need to use ``OrderFee.all`` instead.
  
      :param value: Gross price of this fee
      :type value: Decimal
      :param order: Order this fee is charged with
      :type order: Order
      :param fee_type: The type of the fee, currently ``payment``, ``shipping``, ``service``, ``giftcard``, or ``other``.
      :type fee_type: str
      :param description: A human-readable description of the fee
      :type description: str
      :param internal_type: An internal string to group fees by, e.g. the identifier string of a payment provider
      :type internal_type: str
      :param tax_rate: The tax rate applied to this fee
      :type tax_rate: Decimal
      :param tax_rule: The tax rule applied to this fee
      :type tax_rule: TaxRule
      :param tax_value: The tax amount included in the price
      :type tax_value: Decimal
      :param canceled: True, if this position is canceled and should no longer be regarded
      :type canceled: bool
      """
      FEE_TYPE_PAYMENT = "payment"
      FEE_TYPE_SHIPPING = "shipping"
      FEE_TYPE_SERVICE = "service"
      FEE_TYPE_CANCELLATION = "cancellation"
      FEE_TYPE_OTHER = "other"
      FEE_TYPE_GIFTCARD = "giftcard"
      FEE_TYPES = (
          (FEE_TYPE_PAYMENT, _("Payment fee")),
          (FEE_TYPE_SHIPPING, _("Shipping fee")),
          (FEE_TYPE_SERVICE, _("Service fee")),
          (FEE_TYPE_CANCELLATION, _("Cancellation fee")),
          (FEE_TYPE_OTHER, _("Other fees")),
          (FEE_TYPE_GIFTCARD, _("Gift card")),
      )
  
      value = models.DecimalField(
          decimal_places=2, max_digits=10,
          verbose_name=_("Value")
      )
      order = models.ForeignKey(
          Order,
          verbose_name=_("Order"),
          related_name='all_fees',
          on_delete=models.PROTECT
      )
      fee_type = models.CharField(
          max_length=100, choices=FEE_TYPES
      )
      description = models.CharField(max_length=190, blank=True)
      internal_type = models.CharField(max_length=255, blank=True)
      tax_rate = models.DecimalField(
          max_digits=7, decimal_places=2,
          verbose_name=_('Tax rate')
      )
      tax_rule = models.ForeignKey(
          'TaxRule',
          on_delete=models.PROTECT,
          null=True, blank=True
      )
      tax_value = models.DecimalField(
          max_digits=10, decimal_places=2,
          verbose_name=_('Tax value')
      )
      canceled = models.BooleanField(default=False)
  
      all = ScopedManager(organizer='order__event__organizer')
      objects = ActivePositionManager()
  
      @property
      def net_value(self):
          return self.value - self.tax_value
  
      def __str__(self):
          if self.description:
              return '{} - {}'.format(self.get_fee_type_display(), self.description)
          else:
              return self.get_fee_type_display()
  
      def __repr__(self):
          return '<OrderFee: type %s, value %d>' % (
              self.fee_type, self.value
          )
  
      def _calculate_tax(self, tax_rule=None):
          if tax_rule:
              self.tax_rule = tax_rule
  
          try:
              ia = self.order.invoice_address
          except InvoiceAddress.DoesNotExist:
              ia = None
  
          if not self.tax_rule and self.fee_type == "payment" and self.order.event.settings.tax_rate_default:
              self.tax_rule = self.order.event.settings.tax_rate_default
  
          if self.tax_rule:
              tax = self.tax_rule.tax(self.value, base_price_is='gross', invoice_address=ia, force_fixed_gross_price=True)
              self.tax_rate = tax.rate
              self.tax_value = tax.tax
          else:
              self.tax_value = Decimal('0.00')
              self.tax_rate = Decimal('0.00')
  
      def save(self, *args, **kwargs):
          if self.tax_rule and not self.tax_rule.rate and not self.tax_rule.pk:
              self.tax_rule = None
  
          if self.tax_rate is None:
              self._calculate_tax()
          self.order.touch()
          return super().save(*args, **kwargs)
  
      def delete(self, **kwargs):
          self.order.touch()
          super().delete(**kwargs)
  
  
  class OrderPosition(AbstractPosition):
      """
      An OrderPosition is one line of an order, representing one ordered item
      of a specified type (or variation). This has all properties of
      AbstractPosition.
  
      The default ``OrderPosition.objects`` manager only contains fees that are not ``canceled``. If
      you ant all objects, you need to use ``OrderPosition.all`` instead.
  
      :param order: The order this position is a part of
      :type order: Order
      :param positionid: A local ID of this position, counted for each order individually
      :type positionid: int
      :param tax_rate: The tax rate applied to this position
      :type tax_rate: Decimal
      :param tax_rule: The tax rule applied to this position
      :type tax_rule: TaxRule
      :param tax_value: The tax amount included in the price
      :type tax_value: Decimal
      :param secret: The secret used for ticket QR codes
      :type secret: str
      :param canceled: True, if this position is canceled and should no longer be regarded
      :type canceled: bool
      :param pseudonymization_id: The QR code content for lead scanning
      :type pseudonymization_id: str
      """
      positionid = models.PositiveIntegerField(default=1)
      order = models.ForeignKey(
          Order,
          verbose_name=_("Order"),
          related_name='all_positions',
          on_delete=models.PROTECT
      )
      tax_rate = models.DecimalField(
          max_digits=7, decimal_places=2,
          verbose_name=_('Tax rate')
      )
      tax_rule = models.ForeignKey(
          'TaxRule',
          on_delete=models.PROTECT,
          null=True, blank=True
      )
      tax_value = models.DecimalField(
          max_digits=10, decimal_places=2,
          verbose_name=_('Tax value')
      )
      secret = models.CharField(max_length=255, null=False, blank=False, db_index=True)
      web_secret = models.CharField(max_length=32, default=generate_secret, db_index=True)
      pseudonymization_id = models.CharField(
          max_length=16,
          unique=True,
          db_index=True
      )
      canceled = models.BooleanField(default=False)
  
      all = ScopedManager(organizer='order__event__organizer')
      objects = ActivePositionManager()
  
      class Meta:
          verbose_name = _("Order position")
          verbose_name_plural = _("Order positions")
          ordering = ("positionid", "id")
  
      @cached_property
      def sort_key(self):
          return self.addon_to.positionid if self.addon_to else self.positionid, self.addon_to_id or 0
  
      @property
      def generate_ticket(self):
          if self.item.generate_tickets is not None:
              return self.item.generate_tickets
          return (
              (self.order.event.settings.ticket_download_addons or not self.addon_to_id) and
              (self.event.settings.ticket_download_nonadm or self.item.admission)
          )
  
      @classmethod
      def transform_cart_positions(cls, cp: List, order) -> list:
          from . import Voucher
  
          ops = []
          cp_mapping = {}
          # The sorting key ensures that all addons come directly after the position they refer to
          for i, cartpos in enumerate(sorted(cp, key=lambda c: (c.addon_to_id or c.pk, c.addon_to_id or 0))):
              op = OrderPosition(order=order)
              for f in AbstractPosition._meta.fields:
                  if f.name == 'addon_to':
                      setattr(op, f.name, cp_mapping.get(cartpos.addon_to_id))
                  else:
                      setattr(op, f.name, getattr(cartpos, f.name))
              op._calculate_tax()
              op.positionid = i + 1
              op.save()
              cp_mapping[cartpos.pk] = op
              for answ in cartpos.answers.all():
                  answ.orderposition = op
                  answ.cartposition = None
                  answ.save()
              if cartpos.voucher:
                  Voucher.objects.filter(pk=cartpos.voucher.pk).update(redeemed=F('redeemed') + 1)
                  cartpos.voucher.log_action('pretix.voucher.redeemed', {
                      'order_code': order.code
                  })
  
          # Delete afterwards. Deleting in between might cause deletion of things related to add-ons
          # due to the deletion cascade.
          for cartpos in cp:
              if cartpos.pk:
                  cartpos.addons.all().delete()
                  cartpos.delete()
          return ops
  
      def __str__(self):
          if self.variation:
              return '#{} – {} – {}'.format(
                  self.positionid, str(self.item), str(self.variation)
              )
          return '#{} – {}'.format(self.positionid, str(self.item))
  
      def __repr__(self):
          return '<OrderPosition: item %d, variation %d for order %s>' % (
              self.item.id, self.variation.id if self.variation else 0, self.order_id
          )
  
      def _calculate_tax(self, tax_rule=None):
          self.tax_rule = tax_rule or self.item.tax_rule
          try:
              ia = self.order.invoice_address
          except InvoiceAddress.DoesNotExist:
              ia = None
          if self.tax_rule:
              tax = self.tax_rule.tax(self.price, invoice_address=ia, base_price_is='gross', force_fixed_gross_price=True)
              self.tax_rate = tax.rate
              self.tax_value = tax.tax
              if tax.gross != self.price:
                  raise ValueError('Invalid tax calculation')
          else:
              self.tax_value = Decimal('0.00')
              self.tax_rate = Decimal('0.00')
  
      def save(self, *args, **kwargs):
          from pretix.base.secrets import assign_ticket_secret
  
          if self.tax_rate is None:
              self._calculate_tax()
  
          self.order.touch()
          if not self.pk:
              while not self.secret or OrderPosition.all.filter(
                  secret=self.secret, order__event__organizer_id=self.order.event.organizer_id
              ).exists():
                  assign_ticket_secret(
                      event=self.order.event, position=self, force_invalidate=True, save=False
                  )
  
          if not self.pseudonymization_id:
              self.assign_pseudonymization_id()
  
          return super().save(*args, **kwargs)
  
      @scopes_disabled()
      def assign_pseudonymization_id(self):
          # This omits some character pairs completely because they are hard to read even on screens (1/I and O/0)
          # and includes only one of two characters for some pairs because they are sometimes hard to distinguish in
          # handwriting (2/Z, 4/A, 5/S, 6/G). This allows for better detection e.g. in incoming wire transfers that
          # might include OCR'd handwritten text
          charset = list('ABCDEFGHJKLMNPQRSTUVWXYZ3789')
          while True:
              code = get_random_string(length=10, allowed_chars=charset)
              with scopes_disabled():
                  if not OrderPosition.all.filter(pseudonymization_id=code).exists():
                      self.pseudonymization_id = code
                      return
  
      @property
      def event(self):
          return self.order.event
  
      def send_mail(self, subject: str, template: Union[str, LazyI18nString],
                    context: Dict[str, Any]=None, log_entry_type: str='pretix.event.order.email.sent',
                    user: User=None, headers: dict=None, sender: str=None, invoices: list=None,
                    auth=None, attach_tickets=False):
          """
          Sends an email to the attendee. Basically, this method does two things:
  
          * Call ``pretix.base.services.mail.mail`` with useful values for the ``event``, ``locale``, ``recipient`` and
            ``order`` parameters.
  
          * Create a ``LogEntry`` with the email contents.
  
          :param subject: Subject of the email
          :param template: LazyI18nString or template filename, see ``pretix.base.services.mail.mail`` for more details
          :param context: Dictionary to use for rendering the template
          :param log_entry_type: Key to be used for the log entry
          :param user: Administrative user who triggered this mail to be sent
          :param headers: Dictionary with additional mail headers
          :param sender: Custom email sender.
          :param attach_tickets: Attach tickets of this order, if they are existing and ready to download
          """
          from pretix.base.services.mail import (
              SendMailException, mail, render_mail,
          )
  
          if not self.attendee_email:
              return
  
          for k, v in self.event.meta_data.items():
              context['meta_' + k] = v
  
          with language(self.order.locale, self.order.event.settings.region):
              recipient = self.attendee_email
              try:
                  email_content = render_mail(template, context)
                  mail(
                      recipient, subject, template, context,
                      self.event, self.order.locale, order=self.order, headers=headers, sender=sender,
                      position=self,
                      invoices=invoices, attach_tickets=attach_tickets
                  )
              except SendMailException:
                  raise
              else:
                  self.order.log_action(
                      log_entry_type,
                      user=user,
                      auth=auth,
                      data={
                          'subject': subject,
                          'message': email_content,
                          'recipient': recipient,
                          'invoices': [i.pk for i in invoices] if invoices else [],
                          'attach_tickets': attach_tickets,
                      }
                  )
  
      def resend_link(self, user=None, auth=None):
  
          with language(self.order.locale, self.order.event.settings.region):
              email_template = self.event.settings.mail_text_resend_link
              email_context = get_email_context(event=self.order.event, order=self.order, position=self)
              email_subject = _('Your event registration: %(code)s') % {'code': self.order.code}
              self.send_mail(
                  email_subject, email_template, email_context,
                  'pretix.event.order.email.resend', user=user, auth=auth,
                  attach_tickets=True
              )
  
  
  class CartPosition(AbstractPosition):
      """
      A cart position is similar to an order line, except that it is not
      yet part of a binding order but just placed by some user in his or
      her cart. It therefore normally has a much shorter expiration time
      than an ordered position, but still blocks an item in the quota pool
      as we do not want to throw out users while they're clicking through
      the checkout process. This has all properties of AbstractPosition.
  
      :param event: The event this belongs to
      :type event: Event
      :param cart_id: The user session that contains this cart position
      :type cart_id: str
      """
      event = models.ForeignKey(
          Event,
          verbose_name=_("Event"),
          on_delete=models.CASCADE
      )
      cart_id = models.CharField(
          max_length=255, null=True, blank=True, db_index=True,
          verbose_name=_("Cart ID (e.g. session key)")
      )
      datetime = models.DateTimeField(
          verbose_name=_("Date"),
          auto_now_add=True
      )
      expires = models.DateTimeField(
          verbose_name=_("Expiration date"),
          db_index=True
      )
      includes_tax = models.BooleanField(
          default=True
      )
      override_tax_rate = models.DecimalField(
          max_digits=10, decimal_places=2,
          null=True, blank=True
      )
      is_bundled = models.BooleanField(default=False)
  
      objects = ScopedManager(organizer='event__organizer')
  
      class Meta:
          verbose_name = _("Cart position")
          verbose_name_plural = _("Cart positions")
  
      def __repr__(self):
          return '<CartPosition: item %d, variation %d for cart %s>' % (
              self.item.id, self.variation.id if self.variation else 0, self.cart_id
          )
  
      @property
      def tax_rate(self):
          if self.includes_tax:
              if self.override_tax_rate is not None:
                  return self.override_tax_rate
              return self.item.tax(self.price, base_price_is='gross').rate
          else:
              return Decimal('0.00')
  
      @property
      def tax_value(self):
          if self.includes_tax:
              return self.item.tax(self.price, override_tax_rate=self.override_tax_rate, base_price_is='gross').tax
          else:
              return Decimal('0.00')
  
  
  class InvoiceAddress(models.Model):
      last_modified = models.DateTimeField(auto_now=True)
      order = models.OneToOneField(Order, null=True, blank=True, related_name='invoice_address', on_delete=models.CASCADE)
      is_business = models.BooleanField(default=False, verbose_name=_('Business customer'))
      company = models.CharField(max_length=255, blank=True, verbose_name=_('Company name'))
      name_cached = models.CharField(max_length=255, verbose_name=_('Full name'), blank=True)
      name_parts = FallbackJSONField(default=dict)
      street = models.TextField(verbose_name=_('Address'), blank=False)
      zipcode = models.CharField(max_length=30, verbose_name=_('ZIP code'), blank=False)
      city = models.CharField(max_length=255, verbose_name=_('City'), blank=False)
      country_old = models.CharField(max_length=255, verbose_name=_('Country'), blank=False)
      country = FastCountryField(verbose_name=_('Country'), blank=False, blank_label=_('Select country'),
                                 countries=CachedCountries)
      state = models.CharField(max_length=255, verbose_name=pgettext_lazy('address', 'State'), blank=True)
      vat_id = models.CharField(max_length=255, blank=True, verbose_name=_('VAT ID'),
                                help_text=_('Only for business customers within the EU.'))
      vat_id_validated = models.BooleanField(default=False)
      custom_field = models.CharField(max_length=255, null=True, blank=True)
      internal_reference = models.TextField(
          verbose_name=_('Internal reference'),
          help_text=_('This reference will be printed on your invoice for your convenience.'),
          blank=True,
      )
      beneficiary = models.TextField(
          verbose_name=_('Beneficiary'),
          blank=True
      )
  
      objects = ScopedManager(organizer='order__event__organizer')
  
      def save(self, **kwargs):
          if self.order:
              self.order.touch()
  
          if self.name_parts:
              self.name_cached = self.name
          else:
              self.name_cached = ""
              self.name_parts = {}
          super().save(**kwargs)
  
      @property
      def is_empty(self):
          return (
              not self.name_cached and not self.company and not self.street and not self.zipcode and not self.city
              and not self.internal_reference and not self.beneficiary
          )
  
      @property
      def state_name(self):
          sd = pycountry.subdivisions.get(code='{}-{}'.format(self.country, self.state))
          if sd:
              return sd.name
          return self.state
  
      @property
      def state_for_address(self):
          from pretix.base.settings import COUNTRIES_WITH_STATE_IN_ADDRESS
          if not self.state or str(self.country) not in COUNTRIES_WITH_STATE_IN_ADDRESS:
              return ""
          if COUNTRIES_WITH_STATE_IN_ADDRESS[str(self.country)][1] == 'long':
              return self.state_name
          return self.state
  
      @property
      def name(self):
          if not self.name_parts:
              return ""
          if '_legacy' in self.name_parts:
              return self.name_parts['_legacy']
          if '_scheme' in self.name_parts:
              scheme = PERSON_NAME_SCHEMES[self.name_parts['_scheme']]
          else:
              raise TypeError("Invalid name given.")
          return scheme['concatenation'](self.name_parts).strip()
  
  
  def cachedticket_name(instance, filename: str) -> str:
      secret = get_random_string(length=16, allowed_chars=string.ascii_letters + string.digits)
      return 'tickets/{org}/{ev}/{code}-{no}-{prov}-{secret}.dat'.format(
          org=instance.order_position.order.event.organizer.slug,
          ev=instance.order_position.order.event.slug,
          prov=instance.provider,
          no=instance.order_position.positionid,
          code=instance.order_position.order.code,
          secret=secret,
      )
  
  
  def cachedcombinedticket_name(instance, filename: str) -> str:
      secret = get_random_string(length=16, allowed_chars=string.ascii_letters + string.digits)
      return 'tickets/{org}/{ev}/{code}-{prov}-{secret}.dat'.format(
          org=instance.order.event.organizer.slug,
          ev=instance.order.event.slug,
          prov=instance.provider,
          code=instance.order.code,
          secret=secret
      )
  
  
  class CachedTicket(models.Model):
      order_position = models.ForeignKey(OrderPosition, on_delete=models.CASCADE)
      provider = models.CharField(max_length=255)
      type = models.CharField(max_length=255)
      extension = models.CharField(max_length=255)
      file = models.FileField(null=True, blank=True, upload_to=cachedticket_name, max_length=255)
      created = models.DateTimeField(auto_now_add=True)
  
  
  class CachedCombinedTicket(models.Model):
      order = models.ForeignKey(Order, on_delete=models.CASCADE)
      provider = models.CharField(max_length=255)
      type = models.CharField(max_length=255)
      extension = models.CharField(max_length=255)
      file = models.FileField(null=True, blank=True, upload_to=cachedcombinedticket_name, max_length=255)
      created = models.DateTimeField(auto_now_add=True)
  
  
  class CancellationRequest(models.Model):
      order = models.ForeignKey(Order, on_delete=models.CASCADE, related_name='cancellation_requests')
      created = models.DateTimeField(auto_now_add=True)
      cancellation_fee = models.DecimalField(max_digits=10, decimal_places=2)
      refund_as_giftcard = models.BooleanField(default=False)
  
  
  class RevokedTicketSecret(models.Model):
      event = models.ForeignKey(Event, on_delete=models.CASCADE, related_name='revoked_secrets')
      position = models.ForeignKey(
          OrderPosition,
          on_delete=models.SET_NULL,
          related_name='revoked_secrets',
          null=True,
      )
      secret = models.TextField(db_index=True)
      created = models.DateTimeField(auto_now_add=True)
  
  
  @receiver(post_delete, sender=CachedTicket)
  def cachedticket_delete(sender, instance, **kwargs):
      if instance.file:
          # Pass false so FileField doesn't save the model.
          instance.file.delete(False)
  
  
  @receiver(post_delete, sender=CachedCombinedTicket)
  def cachedcombinedticket_delete(sender, instance, **kwargs):
      if instance.file:
          # Pass false so FileField doesn't save the model.
          instance.file.delete(False)
  
  
  @receiver(post_delete, sender=QuestionAnswer)
  def answer_delete(sender, instance, **kwargs):
      if instance.file:
          # Pass false so FileField doesn't save the model.
          instance.file.delete(False)
  