Discounts: Add applicability date ranges (Z#23151897) (#4927)

* Add event date fields, add preliminary range check

* Remove function, use filtered queryset for subevent id limit

* Improve and fix date range check

* Add formfields

* Add tests

* Improve tests

* Add new fields to API and documentation

* Add migration

* Change description according to suggestion

* Change discount apply signature, remove unnecessary query

* Rename new fields, simplify range check

* Rename fields in template

* Apply suggestions from code review

Co-authored-by: Raphael Michel <michel@rami.io>

---------

Co-authored-by: Raphael Michel <michel@rami.io>

src/pretix/base/migrations/0279_discount_event_date_from_discount_event_date_until.py

@@ -0,0 +1,23 @@
+# Generated by Django 4.2.19 on 2025-03-18 09:12
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('pretixbase', '0278_login_source_add_unique_together'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='discount',
+            name='subevent_date_from',
+            field=models.DateTimeField(blank=True, null=True),
+        ),
+        migrations.AddField(
+            model_name='discount',
+            name='subevent_date_until',
+            field=models.DateTimeField(blank=True, null=True),
+        ),
+    ]

src/pretix/base/models/discount.py

@@ -36,7 +36,9 @@ from django_scopes import ScopedManager
 from pretix.base.decimal import round_decimal
 from pretix.base.models.base import LoggedModel
 
-PositionInfo = namedtuple('PositionInfo', ['item_id', 'subevent_id', 'line_price_gross', 'is_addon_to', 'voucher_discount'])
+PositionInfo = namedtuple('PositionInfo',
+                          ['item_id', 'subevent_id', 'subevent_date_from', 'line_price_gross', 'is_addon_to',
+                           'voucher_discount'])
 
 
 class Discount(LoggedModel):
@@ -171,6 +173,17 @@ class Discount(LoggedModel):
                     "access to sold-out quota will still receive the discount."),
     )
 
+    subevent_date_from = models.DateTimeField(
+        verbose_name=pgettext_lazy("subevent", "Available for dates starting from"),
+        null=True,
+        blank=True,
+    )
+    subevent_date_until = models.DateTimeField(
+        verbose_name=pgettext_lazy("subevent", "Available for dates starting until"),
+        null=True,
+        blank=True,
+    )
+
     # more feature ideas:
     # - max_usages_per_order
     # - promote_to_user_if_almost_satisfied
@@ -355,11 +368,15 @@ class Discount(LoggedModel):
         # First, filter out everything not even covered by our product scope
         condition_candidates = [
             idx
-            for idx, (item_id, subevent_id, line_price_gross, is_addon_to, voucher_discount) in positions.items()
+            for idx, (item_id, subevent_id, subevent_date_from, line_price_gross, is_addon_to, voucher_discount) in
+            positions.items()
             if (
                 (self.condition_all_products or item_id in limit_products) and
                 (self.condition_apply_to_addons or not is_addon_to) and
                 (not self.condition_ignore_voucher_discounted or voucher_discount is None or voucher_discount == Decimal('0.00'))
+                and (not subevent_id or (
+                    self.subevent_date_from is None or subevent_date_from >= self.subevent_date_from)) and (
+                        self.subevent_date_until is None or subevent_date_from <= self.subevent_date_until)
             )
         ]
 
@@ -369,7 +386,8 @@ class Discount(LoggedModel):
             benefit_products = {p.pk for p in self.benefit_limit_products.all()}
             benefit_candidates = [
                 idx
-                for idx, (item_id, subevent_id, line_price_gross, is_addon_to, voucher_discount) in positions.items()
+                for idx, (item_id, subevent_id, subevent_date_from, line_price_gross, is_addon_to, voucher_discount) in
+                positions.items()
                 if (
                     item_id in benefit_products and
                     (self.benefit_apply_to_addons or not is_addon_to) and

src/pretix/base/services/cart.py

@@ -1398,7 +1398,8 @@ class CartManager:
             self.event,
             self._sales_channel.identifier,
             [
-                (cp.item_id, cp.subevent_id, cp.line_price_gross, bool(cp.addon_to), cp.is_bundled, cp.listed_price - cp.price_after_voucher)
+                (cp.item_id, cp.subevent_id, cp.subevent.date_from if cp.subevent_id else None, cp.line_price_gross,
+                 bool(cp.addon_to), cp.is_bundled, cp.listed_price - cp.price_after_voucher)
                 for cp in positions
             ]
         )

src/pretix/base/services/cross_selling.py

@@ -120,7 +120,8 @@ class CrossSellingService:
             self.event,
             self.sales_channel,
             [
-                (cp.item_id, cp.subevent_id, cp.line_price_gross, bool(cp.addon_to), cp.is_bundled,
+                (cp.item_id, cp.subevent_id, cp.subevent.date_from if cp.subevent_id else None, cp.line_price_gross,
+                 bool(cp.addon_to), cp.is_bundled,
                  cp.listed_price - cp.price_after_voucher)
                 for cp in self.cartpositions
             ],

src/pretix/base/services/orders.py

@@ -875,7 +875,8 @@ def _check_positions(event: Event, now_dt: datetime, time_machine_now_dt: dateti
         event,
         sales_channel.identifier,
         [
-            (cp.item_id, cp.subevent_id, cp.line_price_gross, bool(cp.addon_to), cp.is_bundled, cp.listed_price - cp.price_after_voucher)
+            (cp.item_id, cp.subevent_id, cp.subevent.date_from if cp.subevent_id else None, cp.line_price_gross,
+             bool(cp.addon_to), cp.is_bundled, cp.listed_price - cp.price_after_voucher)
             for cp in sorted_positions
         ]
     )

src/pretix/base/services/pricing.py

@@ -21,6 +21,7 @@
 #
 import re
 from collections import defaultdict
+from datetime import datetime
 from decimal import Decimal
 from typing import List, Optional, Tuple, Union
 
@@ -162,14 +163,14 @@ def get_line_price(price_after_voucher: Decimal, custom_price_input: Decimal, cu
 
 
 def apply_discounts(event: Event, sales_channel: Union[str, SalesChannel],
-                    positions: List[Tuple[int, Optional[int], Decimal, bool, bool, Decimal]],
+                    positions: List[Tuple[int, Optional[int], Optional[datetime], Decimal, bool, bool, Decimal]],
                     collect_potential_discounts: Optional[defaultdict]=None) -> List[Tuple[Decimal, Optional[Discount]]]:
     """
     Applies any dynamic discounts to a cart
 
     :param event: Event the cart belongs to
     :param sales_channel: Sales channel the cart was created with
-    :param positions: Tuple of the form ``(item_id, subevent_id, line_price_gross, is_addon_to, is_bundled, voucher_discount)``
+    :param positions: Tuple of the form ``(item_id, subevent_id, subevent_date_from, line_price_gross, is_addon_to, is_bundled, voucher_discount)``
     :param collect_potential_discounts: If a `defaultdict(list)` is supplied, all discounts that could be applied to the cart
     based on the "consumed" items, but lack matching "benefitting" items will be collected therein.
     The dict will contain a mapping from index in the `positions` list of the item that could be consumed, to a list
@@ -191,12 +192,14 @@ def apply_discounts(event: Event, sales_channel: Union[str, SalesChannel],
     ).prefetch_related('condition_limit_products', 'benefit_limit_products').order_by('position', 'pk')
     for discount in discount_qs:
         result = discount.apply({
-            idx: PositionInfo(item_id, subevent_id, line_price_gross, is_addon_to, voucher_discount)
-            for idx, (item_id, subevent_id, line_price_gross, is_addon_to, is_bundled, voucher_discount) in enumerate(positions)
+            idx: PositionInfo(item_id, subevent_id, subevent_date_from, line_price_gross, is_addon_to, voucher_discount)
+            for
+            idx, (item_id, subevent_id, subevent_date_from, line_price_gross, is_addon_to, is_bundled, voucher_discount)
+            in enumerate(positions)
             if not is_bundled and idx not in new_prices
         }, collect_potential_discounts)
         for k in result.keys():
             result[k] = (result[k], discount)
         new_prices.update(result)
 
-    return [new_prices.get(idx, (p[2], None)) for idx, p in enumerate(positions)]
+    return [new_prices.get(idx, (p[3], None)) for idx, p in enumerate(positions)]