Add support for reserved seating (#1228)

* Initial work on seating

* Add seat guids

* Add product_list_top

* CartAdd: Ignore item when a seat is passed

* Cart display

* product_list_top → render_seating_plan

* Render seating plan in voucher redemption

* Fix failing tests

* Add tests for extending cart positions with seats

* Add subevent_forms to docs

* Update schema, migrations

* Dealing with expired orders

* steps to order change

* Change order positions

* Allow to add seats

* tests for ocm

* Fix things after rebase

* Seating plans API

* Add more tests for cart behaviour

* Widget support

* Adjust widget tests

* Re-enable CSP

* Update schema

* Api: position.seat

* Add guid to word list

* API: (sub)event.seating_plan

* Vali fixes

* Fix api

* Fix reference in test

* Fix test for real

src/pretix/base/models/__init__.py

@@ -24,6 +24,7 @@ from .orders import (
 from .organizer import (
     Organizer, Organizer_SettingsStore, Team, TeamAPIToken, TeamInvite,
 )
+from .seating import Seat, SeatCategoryMapping, SeatingPlan
 from .tax import TaxRule
 from .vouchers import Voucher
 from .waitinglist import WaitingListEntry

src/pretix/base/models/event.py

@@ -336,6 +336,8 @@ class Event(EventMixin, LoggedModel):
         verbose_name=_('Event series'),
         default=False
     )
+    seating_plan = models.ForeignKey('SeatingPlan', on_delete=models.PROTECT, null=True, blank=True,
+                                     related_name='events')
 
     objects = ScopedManager(organizer='organizer')
 
@@ -348,6 +350,26 @@ class Event(EventMixin, LoggedModel):
     def __str__(self):
         return str(self.name)
 
+    @property
+    def free_seats(self):
+        from .orders import CartPosition, Order, OrderPosition
+        return self.seats.annotate(
+            has_order=Exists(
+                OrderPosition.objects.filter(
+                    order__event=self,
+                    seat_id=OuterRef('pk'),
+                    order__status__in=[Order.STATUS_PENDING, Order.STATUS_PAID]
+                )
+            ),
+            has_cart=Exists(
+                CartPosition.objects.filter(
+                    event=self,
+                    seat_id=OuterRef('pk'),
+                    expires__gte=now()
+                )
+            )
+        ).filter(has_order=False, has_cart=False, blocked=False)
+
     @property
     def presale_has_ended(self):
         if self.has_subevents:
@@ -531,6 +553,24 @@ class Event(EventMixin, LoggedModel):
             for i in items:
                 cl.limit_products.add(item_map[i.pk])
 
+        if other.seating_plan:
+            if other.seating_plan.organizer_id == self.organizer_id:
+                self.seating_plan = other.seating_plan
+            else:
+                self.organizer.seating_plans.create(name=other.seating_plan.name, layout=other.seating_plan.layout)
+            self.save()
+
+        for m in other.seat_category_mappings.filter(subevent__isnull=True):
+            m.pk = None
+            m.event = self
+            m.product = item_map[m.product_id]
+            m.save()
+
+        for s in other.seats.filter(subevent__isnull=True):
+            s.pk = None
+            s.event = self
+            s.save()
+
         for s in other.settings._objects.all():
             s.object = self
             s.pk = None
@@ -874,6 +914,8 @@ class SubEvent(EventMixin, LoggedModel):
         null=True, blank=True,
         verbose_name=_("Frontpage text")
     )
+    seating_plan = models.ForeignKey('SeatingPlan', on_delete=models.PROTECT, null=True, blank=True,
+                                     related_name='subevents')
 
     items = models.ManyToManyField('Item', through='SubEventItem')
     variations = models.ManyToManyField('ItemVariation', through='SubEventItemVariation')
@@ -888,6 +930,28 @@ class SubEvent(EventMixin, LoggedModel):
     def __str__(self):
         return '{} - {}'.format(self.name, self.get_date_range_display())
 
+    @property
+    def free_seats(self):
+        from .orders import CartPosition, Order, OrderPosition
+        return self.seats.annotate(
+            has_order=Exists(
+                OrderPosition.objects.filter(
+                    order__event_id=self.event_id,
+                    subevent=self,
+                    seat_id=OuterRef('pk'),
+                    order__status__in=[Order.STATUS_PENDING, Order.STATUS_PAID]
+                )
+            ),
+            has_cart=Exists(
+                CartPosition.objects.filter(
+                    event_id=self.event_id,
+                    subevent=self,
+                    seat_id=OuterRef('pk'),
+                    expires__gte=now()
+                )
+            )
+        ).filter(has_order=False, has_cart=False, blocked=False)
+
     @cached_property
     def settings(self):
         return self.event.settings

src/pretix/base/models/orders.py

@@ -630,7 +630,7 @@ class Order(LockModel, LoggedModel):
             ), tz)
         return term_last
 
-    def _can_be_paid(self, count_waitinglist=True, ignore_date=False) -> Union[bool, str]:
+    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."),
@@ -638,29 +638,37 @@ class Order(LockModel, LoggedModel):
                       "payments should be accepted in the payment settings."),
             'require_approval': _('This order is not yet approved by the event organizer.')
         }
-        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 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:
+        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)
+        return self._is_still_available(count_waitinglist=count_waitinglist, force=force)
 
-    def _is_still_available(self, now_dt: datetime=None, count_waitinglist=True) -> Union[bool, str]:
+    def _is_still_available(self, now_dt: datetime=None, count_waitinglist=True, force=False) -> Union[bool, str]:
         error_messages = {
             'unavailable': _('The ordered product "{item}" is no longer available.'),
+            'seat_unavailable': _('The seat "{seat}" is no longer available.'),
         }
         now_dt = now_dt or now()
-        positions = self.positions.all().select_related('item', 'variation')
+        positions = self.positions.all().select_related('item', 'variation', 'seat')
         quota_cache = {}
         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
+
                 quotas = list(op.quotas)
                 if len(quotas) == 0:
                     raise Quota.QuotaExceededException(error_messages['unavailable'].format(
@@ -938,6 +946,8 @@ class AbstractPosition(models.Model):
     :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,
@@ -984,6 +994,9 @@ class AbstractPosition(models.Model):
         verbose_name=_("Meta information"),
         null=True, blank=True
     )
+    seat = models.ForeignKey(
+        'Seat', null=True, blank=True, on_delete=models.PROTECT
+    )
 
     class Meta:
         abstract = True
@@ -1183,8 +1196,8 @@ class OrderPayment(models.Model):
 
     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)
-        if not force and can_be_paid is not True:
+        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)

src/pretix/base/models/seating.py

@@ -0,0 +1,111 @@
+import json
+from collections import namedtuple
+
+import jsonschema
+from django.contrib.staticfiles import finders
+from django.core.exceptions import ValidationError
+from django.db import models
+from django.utils.deconstruct import deconstructible
+from django.utils.timezone import now
+from django.utils.translation import ugettext_lazy as _
+
+from pretix.base.models import Event, Item, LoggedModel, Organizer, SubEvent
+
+
+@deconstructible
+class SeatingPlanLayoutValidator:
+    def __call__(self, value):
+        if not isinstance(value, dict):
+            try:
+                val = json.loads(value)
+            except ValueError:
+                raise ValidationError(_('Your layout file is not a valid JSON file.'))
+        else:
+            val = value
+        with open(finders.find('seating/seating-plan.schema.json'), 'r') as f:
+            schema = json.loads(f.read())
+        try:
+            jsonschema.validate(val, schema)
+        except jsonschema.ValidationError as e:
+            raise ValidationError(_('Your layout file is not a valid seating plan. Error message: {}').format(str(e)))
+
+
+class SeatingPlan(LoggedModel):
+    """
+    Represents an abstract seating plan, without relation to any event.
+    """
+    name = models.CharField(max_length=190, verbose_name=_('Name'))
+    organizer = models.ForeignKey(Organizer, related_name='seating_plans', on_delete=models.CASCADE)
+    layout = models.TextField(validators=[SeatingPlanLayoutValidator()])
+
+    Category = namedtuple('Categrory', 'name')
+    RawSeat = namedtuple('Seat', 'name guid number row category')
+
+    def __str__(self):
+        return self.name
+
+    @property
+    def layout_data(self):
+        return json.loads(self.layout)
+
+    @layout_data.setter
+    def layout_data(self, v):
+        self.layout = json.dumps(v)
+
+    def get_categories(self):
+        return [
+            self.Category(name=c['name'])
+            for c in self.layout_data['categories']
+        ]
+
+    def iter_all_seats(self):
+        for z in self.layout_data['zones']:
+            for r in z['rows']:
+                for s in r['seats']:
+                    yield self.RawSeat(
+                        number=s['seat_number'],
+                        guid=s['seat_guid'],
+                        name='{} {}'.format(r['row_number'], s['seat_number']),  # TODO: Zone? Variable scheme?
+                        row=r['row_number'],
+                        category=s['category']
+                    )
+
+
+class SeatCategoryMapping(models.Model):
+    """
+    Input seating plans have abstract "categories", such as "Balcony seat", etc. This model maps them to actual
+    pretix product on a per-(sub)event level.
+    """
+    event = models.ForeignKey(Event, related_name='seat_category_mappings', on_delete=models.CASCADE)
+    subevent = models.ForeignKey(SubEvent, null=True, blank=True, related_name='seat_category_mappings', on_delete=models.CASCADE)
+    layout_category = models.CharField(max_length=190)
+    product = models.ForeignKey(Item, related_name='seat_category_mappings', on_delete=models.CASCADE)
+
+
+class Seat(models.Model):
+    """
+    This model is used to represent every single specific seat within an (sub)event that can be selected. It's mainly
+    used for internal bookkeeping and not to be modified by users directly.
+    """
+    event = models.ForeignKey(Event, related_name='seats', on_delete=models.CASCADE)
+    subevent = models.ForeignKey(SubEvent, null=True, blank=True, related_name='seats', on_delete=models.CASCADE)
+    name = models.CharField(max_length=190)
+    seat_guid = models.CharField(max_length=190, db_index=True)
+    product = models.ForeignKey('Item', null=True, blank=True, related_name='seats', on_delete=models.CASCADE)
+    blocked = models.BooleanField(default=False)
+
+    def __str__(self):
+        return self.name
+
+    def is_available(self, ignore_cart=None, ignore_orderpos=None):
+        from .orders import Order
+
+        if self.blocked:
+            return False
+        opqs = self.orderposition_set.filter(order__status__in=[Order.STATUS_PENDING, Order.STATUS_PAID])
+        cpqs = self.cartposition_set.filter(expires__gte=now())
+        if ignore_cart:
+            cpqs = cpqs.exclude(pk=ignore_cart.pk)
+        if ignore_orderpos:
+            opqs = opqs.exclude(pk=ignore_orderpos.pk)
+        return not opqs.exists() and not cpqs.exists()

src/pretix/base/models/vouchers.py

@@ -10,6 +10,8 @@ from django.utils.timezone import now
 from django.utils.translation import pgettext_lazy, ugettext_lazy as _
 from django_scopes import ScopedManager, scopes_disabled
 
+from pretix.base.models import SeatCategoryMapping
+
 from ..decimal import round_decimal
 from .base import LoggedModel
 from .event import Event, SubEvent
@@ -395,3 +397,11 @@ class Voucher(LoggedModel):
         """
 
         return Order.objects.filter(all_positions__voucher__in=[self]).distinct()
+
+    def seating_available(self):
+        kwargs = {}
+        if self.subevent:
+            kwargs['subevent'] = self.subevent
+        if self.quota_id:
+            return SeatCategoryMapping.objects.filter(product__quotas__pk=self.quota_id, **kwargs).exists()
+        return self.item.seat_category_mappings.filter(**kwargs).exists()