Invoicing: Configurable service date

src/pretix/base/invoicing/pdf.py

@@ -19,6 +19,7 @@
 # You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
 # <https://www.gnu.org/licenses/>.
 #
+import datetime
 import logging
 import math
 import re
@@ -526,6 +527,20 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
         textobject.textLine(self._normalize(self._upper(pgettext('invoice', 'Event'))))
         canvas.drawText(textobject)
 
+    def _date_range_in_header(self):
+        if self.invoice.event.has_subevents or not self.invoice.event.settings.show_dates_on_frontpage:
+            return None, None
+        tz = self.invoice.event.timezone
+        show_end_date = (
+            self.invoice.event.settings.show_date_to and
+            self.invoice.event.date_to and
+            self.invoice.event.date_to.astimezone(tz).date() != self.invoice.event.date_from.astimezone(tz).date()
+        )
+        if show_end_date:
+            return self.invoice.event.date_from.astimezone(tz).date(), self.invoice.event.date_to.astimezone(tz).date()
+        else:
+            return self.invoice.event.date_from.astimezone(tz).date(), None
+
     def _draw_event(self, canvas):
         def shorten(txt):
             txt = str(txt)
@@ -539,25 +554,17 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
                 p_size = p.wrap(self.event_width, self.event_height)
             return txt
 
-        if not self.invoice.event.has_subevents and self.invoice.event.settings.show_dates_on_frontpage:
-            tz = self.invoice.event.timezone
-            show_end_date = (
-                self.invoice.event.settings.show_date_to and
-                self.invoice.event.date_to and
-                self.invoice.event.date_to.astimezone(tz).date() != self.invoice.event.date_from.astimezone(tz).date()
+        d_from, d_to = self._date_range_in_header()
+        if d_from and d_to:
+            p_str = (
+                shorten(self.invoice.event.name) + '\n' +
+                pgettext('invoice', '{from_date}\nuntil {to_date}').format(
+                    from_date=date_format(d_from, "DATE_FORMAT"),
+                    to_date=date_format(d_to, "DATE_FORMAT"),
+                )
             )
-            if show_end_date:
-                p_str = (
-                    shorten(self.invoice.event.name) + '\n' +
-                    pgettext('invoice', '{from_date}\nuntil {to_date}').format(
-                        from_date=self.invoice.event.get_date_from_display(show_times=False),
-                        to_date=self.invoice.event.get_date_to_display(show_times=False)
-                    )
-                )
-            else:
-                p_str = (
-                    shorten(self.invoice.event.name) + '\n' + self.invoice.event.get_date_from_display(show_times=False)
-                )
+        elif d_from:
+            p_str = shorten(self.invoice.event.name) + '\n' + date_format(d_from, "DATE_FORMAT")
         else:
             p_str = shorten(self.invoice.event.name)
 
@@ -685,7 +692,14 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
         return story
 
     def _get_story(self, doc):
-        has_taxes = any(il.tax_value for il in self.invoice.lines.all()) or self.invoice.reverse_charge
+        all_lines = list(self.invoice.lines.all())
+        has_taxes = any(il.tax_value for il in all_lines) or self.invoice.reverse_charge
+        header_dates = self._date_range_in_header()
+        tz = self.invoice.event.timezone
+        has_multiple_service_dates = len(set(
+            (il.period_start, il.period_end) for il in all_lines
+        )) > 1
+        request_show_service_date = False
 
         story = [
             NextPageTemplate('FirstPage'),
@@ -729,15 +743,75 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
             )]
 
         def _group_key(line):
-            return (line.description, line.tax_rate, line.tax_name, line.net_value, line.gross_value, line.subevent_id,
-                    line.event_date_from, line.event_date_to)
+            return (line.description, line.tax_rate, line.tax_name, line.net_value, line.gross_value, line.subevent,
+                    line.period_start, line.period_end)
+
+        def day(dt: datetime.datetime) -> datetime.date:
+            if dt is None:
+                return None
+            return dt.astimezone(tz).date()
 
         total = Decimal('0.00')
-        for (description, tax_rate, tax_name, net_value, gross_value, *ignored), lines in addon_aware_groupby(
-            self.invoice.lines.all(),
+        for (description, tax_rate, tax_name, net_value, gross_value, subevent, period_start, period_end), lines in addon_aware_groupby(
+            all_lines,
             key=_group_key,
             is_addon=lambda l: l.description.startswith("  +"),
         ):
+            # Try to be clever and figure out when organizers would want to show the period. This heuristic is
+            # not perfect and the only "fully correct" way would be to include the period on every line always,
+            # however this will cause confusion (a) due to useless repetition of the same date all over the invoice
+            # (b) due to not respecting the show_date_to setting of events in cases where we could have respected it.
+            # Still, we want to show the date explicitly if its different to the event or invoice date.
+            period_start_day = day(period_start)
+            period_end_day = day(period_end)
+            if period_start and period_end and period_end_day != period_start_day:
+                # It's a multi-day period, such as the validity of the ticket or an event date period
+
+                if period_start_day == header_dates[0] and period_end_day == header_dates[1]:
+                    # This is the exact event period we already printed in the header, no need to repeat it.
+                    period_line = ""
+
+                elif (self.event.has_subevents and subevent and day(subevent.date_from) == period_start_day and
+                      day(subevent.date_to) == period_end_day):
+                    # For subevents, build_invoice already includes the date in the description in the event-default format.
+                    period_line = ""
+
+                else:
+                    period_line = f"{date_format(period_start_day, 'SHORT_DATE_FORMAT')} – {date_format(period_end_day, 'SHORT_DATE_FORMAT')}"
+
+            elif period_start or period_end:
+                # It's a single-day period
+
+                delivery_day = period_end_day or period_start_day
+                if delivery_day in header_dates:
+                    # This is the event date we already printed in the header, no need to repeat it.
+                    period_line = ""
+
+                elif self.event.has_subevents and subevent and delivery_day in (day(subevent.date_from), day(subevent.date_to)):
+                    # For subevents, build_invoice already includes the date in the description in the event-default format.
+                    period_line = ""
+
+                elif (delivery_day == self.invoice.date) and header_dates[0] is None:
+                    # This is a shop that doesn't show the date of the event in the header, and the period is the invoice
+                    # date. We assume that this is an 'everything is executed immediately' situation and do not want to
+                    # confuse with showing additional dates on the invoice. This is the case that is not guaranteed to be
+                    # correct in all cases and might need to change in the future. If customers have legal concerns, a
+                    # quick fix is including a sentence like "Delivery date is the invoice date unless otherwise indicated:"
+                    # in a custom text on the invoice.
+                    period_line = ""
+
+                else:
+                    period_line = date_format(delivery_day, 'SHORT_DATE_FORMAT')
+            else:
+                # No period known
+                period_line = ""
+
+            if not has_multiple_service_dates and period_line:
+                # Group together at the end of the invoice
+                request_show_service_date = period_line
+            elif period_line:
+                description += "\n" + period_line
+
             lines = list(lines)
             if has_taxes:
                 if len(lines) > 1:
@@ -746,6 +820,7 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
                         gross_price=money_filter(gross_value, self.invoice.event.currency),
                     )
                     description = description + "\n" + single_price_line
+
                 tdata.append((
                     FontFallbackParagraph(
                         self._clean_text(description, tags=['br']),
@@ -850,6 +925,12 @@ class ClassicInvoiceRenderer(BaseReportlabInvoiceRenderer):
 
         story.append(Spacer(1, 10 * mm))
 
+        if request_show_service_date:
+            story.append(FontFallbackParagraph(
+                self._normalize(pgettext('invoice', 'Invoice period: {daterange}').format(daterange=request_show_service_date)),
+                self.stylesheet['Normal']
+            ))
+
         if self.invoice.payment_provider_text:
             story.append(FontFallbackParagraph(
                 self._normalize(self.invoice.payment_provider_text),

src/pretix/base/migrations/0289_invoiceline_period.py

@@ -0,0 +1,78 @@
+# Generated by Django 4.2.17 on 2025-09-08 08:14
+from django.core.cache import cache
+from django.db import migrations
+
+
+def set_invoice_period(apps, schema_editor):
+    EventSettingsStore = apps.get_model("pretixbase", "Event_SettingsStore")
+    ev_seen = set()
+    insert_queue = []
+    flush_queue = []
+
+    def store():
+        EventSettingsStore.objects.bulk_create(
+            insert_queue,
+            update_conflicts=True,
+            update_fields=["value"],
+            unique_fields=["object", "key"],
+        )
+        cache.delete_many(flush_queue)
+        flush_queue.clear()
+        insert_queue.clear()
+
+    # Existing events that use pretix-zugferd and have explicitly disabled delivery dates
+    for setting in EventSettingsStore.objects.filter(key="zugferd_include_delivery_date", value="False"):
+        flush_queue.append("hierarkey_{}_{}".format("event", setting.object_id))
+        insert_queue.append(
+            EventSettingsStore(
+                object_id=setting.object_id,
+                key="invoice_period",
+                value="invoice_date",
+            )
+        )
+        ev_seen.add(setting.object_id)
+
+        if len(insert_queue) > 1000:
+            store()
+
+    # Existing events that previously hid their date on invoices
+    for setting in EventSettingsStore.objects.filter(key="show_dates_on_frontpage", value="False"):
+        if setting.object_id in ev_seen:
+            continue
+
+        flush_queue.append("hierarkey_{}_{}".format("event", setting.object_id))
+        insert_queue.append(
+            EventSettingsStore(
+                object_id=setting.object_id,
+                key="invoice_period",
+                value="auto_no_event",
+            )
+        )
+
+        if len(insert_queue) > 1000:
+            store()
+
+    store()
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("pretixbase", "0288_invoice_transmission"),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name="invoiceline",
+            old_name="event_date_to",
+            new_name="period_end",
+        ),
+        migrations.RenameField(
+            model_name="invoiceline",
+            old_name="event_date_from",
+            new_name="period_start",
+        ),
+        migrations.RunPython(
+            set_invoice_period,
+            migrations.RunPython.noop,
+        )
+    ]

src/pretix/base/models/invoices.py

@@ -33,6 +33,7 @@
 # License for the specific language governing permissions and limitations under the License.
 
 import string
+import warnings
 from decimal import Decimal
 
 import pycountry
@@ -404,10 +405,10 @@ class InvoiceLine(models.Model):
     :type tax_name: str
     :param subevent: The subevent this line refers to
     :type subevent: SubEvent
-    :param event_date_from: Event date of the (sub)event at the time the invoice was created
-    :type event_date_from: datetime
-    :param event_date_to: Event end date of the (sub)event at the time the invoice was created
-    :type event_date_to: datetime
+    :param period_start: Start if service period invoiced
+    :type period_start: datetime
+    :param period_end: End of service period invoiced
+    :type period_end: datetime
     :param event_location: Event location of the (sub)event at the time the invoice was created
     :type event_location: str
     :param item: The item this line refers to
@@ -426,8 +427,8 @@ class InvoiceLine(models.Model):
     tax_name = models.CharField(max_length=190)
     tax_code = models.CharField(max_length=190, null=True, blank=True)
     subevent = models.ForeignKey('SubEvent', null=True, blank=True, on_delete=models.PROTECT)
-    event_date_from = models.DateTimeField(null=True)
-    event_date_to = models.DateTimeField(null=True)
+    period_start = models.DateTimeField(null=True)
+    period_end = models.DateTimeField(null=True)
     event_location = models.TextField(null=True, blank=True)
     item = models.ForeignKey('Item', null=True, blank=True, on_delete=models.PROTECT)
     variation = models.ForeignKey('ItemVariation', null=True, blank=True, on_delete=models.PROTECT)
@@ -444,3 +445,35 @@ class InvoiceLine(models.Model):
 
     def __str__(self):
         return 'Line {} of invoice {}'.format(self.position, self.invoice)
+
+    @property
+    def event_date_from(self):
+        warnings.warn(
+            'InvoiceLine.event_date_from is deprecated, use period_start instead,',
+            category=DeprecationWarning,
+        )
+        return self.period_start
+
+    @event_date_from.setter
+    def event_date_from(self, value):
+        warnings.warn(
+            'InvoiceLine.event_date_from is deprecated, use period_start instead,',
+            category=DeprecationWarning,
+        )
+        self.period_start = value
+
+    @property
+    def event_date_to(self):
+        warnings.warn(
+            'InvoiceLine.event_date_to is deprecated, use period_end instead,',
+            category=DeprecationWarning,
+        )
+        return self.period_end
+
+    @event_date_to.setter
+    def event_date_to(self, value):
+        warnings.warn(
+            'InvoiceLine.event_date_to is deprecated, use period_end instead,',
+            category=DeprecationWarning,
+        )
+        self.period_to = value

src/pretix/base/services/invoices.py

@@ -82,6 +82,10 @@ def build_invoice(invoice: Invoice) -> Invoice:
 
     lp = invoice.order.payments.last()
 
+    min_period_start = None
+    max_period_end = None
+    now_dt = now()
+
     with (language(invoice.locale, invoice.event.settings.region)):
         invoice.invoice_from = invoice.event.settings.get('invoice_address_from')
         invoice.invoice_from_name = invoice.event.settings.get('invoice_address_from_name')
@@ -208,7 +212,9 @@ def build_invoice(invoice: Invoice) -> Invoice:
         positions = list(
             invoice.order.positions.select_related('addon_to', 'item', 'tax_rule', 'subevent', 'variation').annotate(
                 addon_c=Count('addons')
-            ).prefetch_related('answers', 'answers__options', 'answers__question').order_by('positionid', 'id')
+            ).prefetch_related(
+                'answers', 'answers__options', 'answers__question', 'granted_memberships',
+            ).order_by('positionid', 'id')
         )
 
         reverse_charge = False
@@ -267,6 +273,10 @@ def build_invoice(invoice: Invoice) -> Invoice:
                     location=_location_oneliner(location)
                 )
 
+            period_start, period_end = _service_period_for_position(invoice, p, now_dt)
+            min_period_start = min(min_period_start or period_start, period_start)
+            max_period_end = min(max_period_end or period_end, period_end)
+
             InvoiceLine.objects.create(
                 position=i,
                 invoice=invoice,
@@ -277,8 +287,8 @@ def build_invoice(invoice: Invoice) -> Invoice:
                 item=p.item,
                 variation=p.variation,
                 attendee_name=p.attendee_name if invoice.event.settings.invoice_attendee_name else None,
-                event_date_from=p.subevent.date_from if invoice.event.has_subevents else invoice.event.date_from,
-                event_date_to=p.subevent.date_to if invoice.event.has_subevents else invoice.event.date_to,
+                period_start=period_start,
+                period_end=period_end,
                 event_location=location if invoice.event.settings.invoice_event_location else None,
                 tax_rate=p.tax_rate,
                 tax_code=p.tax_code,
@@ -301,13 +311,29 @@ def build_invoice(invoice: Invoice) -> Invoice:
                 fee_title = _(fee.get_fee_type_display())
                 if fee.description:
                     fee_title += " - " + fee.description
+
+            if min_period_start and max_period_end:
+                # Consider fees to have the same service period as the products sold
+                period_start = min_period_start
+                period_end = max_period_end
+            else:
+                # Usually can only happen if everything except a cancellation fee is removed
+                if invoice.event.settings.invoice_period in ("auto", "auto_no_event", "event_date") and not invoice.event.has_subevents:
+                    # Non-series event, let's be backwards-compatible and tag everything with the event period
+                    period_start = invoice.event.date_from
+                    period_end = invoice.event.date_to
+                else:
+                    # We could try to work from the canceled positions, but it doesn't really make sense. A cancellation
+                    # fee is not "delivered" at the event date, it is rather effective right now.
+                    period_start = period_end = now()
+
             InvoiceLine.objects.create(
                 position=i + offset,
                 invoice=invoice,
                 description=fee_title,
                 gross_value=fee.value,
-                event_date_from=None if invoice.event.has_subevents else invoice.event.date_from,
-                event_date_to=None if invoice.event.has_subevents else invoice.event.date_to,
+                period_start=period_start,
+                period_end=period_end,
                 event_location=(
                     None if invoice.event.has_subevents
                     else (str(invoice.event.location)
@@ -351,6 +377,55 @@ def build_cancellation(invoice: Invoice):
     return invoice
 
 
+def _service_period_for_position(invoice, position, invoice_dt):
+    if invoice.event.settings.invoice_period in ("auto", "auto_no_event"):
+        if position.valid_from and position.valid_until:
+            period_start = position.valid_from
+            period_end = position.valid_until
+        elif position.valid_from:
+            period_start = position.valid_from
+            period_end = position.valid_from  # weird, but we have nothing else to base this on
+        elif position.valid_until:
+            period_start = min(invoice.order.datetime, position.valid_until)
+            period_end = position.valid_until
+        elif memberships := list(position.granted_memberships.all()):
+            period_start = min(m.date_start for m in memberships)
+            period_end = max(m.date_end for m in memberships)
+        elif invoice.event.has_subevents:
+            if position.subevent:
+                period_start = position.subevent.date_from
+                period_end = position.subevent.date_to
+            else:
+                # Currently impossible case, but might not be in the future and never makes
+                # sense to use the event date here
+                period_start = invoice_dt
+                period_end = invoice_dt
+        elif invoice.event.settings.invoice_period == "auto_no_event":
+            period_start = invoice_dt
+            period_end = invoice_dt
+        else:
+            period_start = invoice.event.date_from
+            period_end = invoice.event.date_to
+    elif invoice.event.settings.invoice_period == "order_date":
+        period_start = invoice.order.datetime
+        period_end = invoice.order.datetime
+    elif invoice.event.settings.invoice_period == "event_date":
+        if position.subevent:
+            period_start = position.subevent.date_from
+            period_end = position.subevent.date_to
+        else:
+            period_start = invoice.event.date_from
+            period_end = invoice.event.date_to
+    elif invoice.event.settings.invoice_period == "invoice_date":
+        period_start = period_end = invoice_dt
+    else:
+        raise ValueError(f"Invalid invoice period setting '{invoice.event.settings.invoice_period}'")
+
+    if not period_end:
+        period_end = period_start
+    return period_start, period_end
+
+
 def generate_cancellation(invoice: Invoice, trigger_pdf=True):
     if invoice.canceled:
         raise ValueError("Invoice should not be canceled twice.")
@@ -456,6 +531,12 @@ def build_preview_invoice_pdf(event):
     if not locale or locale == '__user__':
         locale = event.settings.locale
 
+    if event.settings.invoice_period in ("auto", "auto_no_event", "event_date"):
+        period_start = event.date_from
+        period_end = event.date_to or event.date_from
+    else:
+        period_start = period_end = timezone.now()
+
     with rolledback_transaction(), language(locale, event.settings.region):
         order = event.orders.create(
             status=Order.STATUS_PENDING, datetime=timezone.now(),
@@ -506,8 +587,8 @@ def build_preview_invoice_pdf(event):
                         invoice=invoice, description=_("Sample product {}").format(i + 1),
                         gross_value=tax.gross, tax_value=tax.tax,
                         tax_rate=tax.rate, tax_name=tax.name, tax_code=tax.code,
-                        event_date_from=event.date_from,
-                        event_date_to=event.date_to,
+                        period_start=period_start,
+                        period_end=period_end,
                         event_location=event.settings.invoice_event_location,
                     )
         else:
@@ -515,8 +596,8 @@ def build_preview_invoice_pdf(event):
                 InvoiceLine.objects.create(
                     invoice=invoice, description=_("Sample product A"),
                     gross_value=100, tax_value=0, tax_rate=0, tax_code=None,
-                    event_date_from=event.date_from,
-                    event_date_to=event.date_to,
+                    period_start=period_start,
+                    period_end=period_end,
                     event_location=event.settings.invoice_event_location,
                 )
 

src/pretix/base/settings.py

@@ -1098,6 +1098,35 @@ DEFAULTS = {
             help_text=_("Invoices will never be automatically generated for free orders.")
         )
     },
+    'invoice_period': {
+        'default': 'auto',
+        'type': str,
+        'form_class': forms.ChoiceField,
+        'serializer_class': serializers.ChoiceField,
+        'serializer_kwargs': dict(
+            choices=(
+                ('auto', _('Automatic based on ticket-specific validity, membership validity, event series date, or event date)')),
+                ('auto_no_event', _('Automatic, but prefer invoice date over event date')),
+                ('event_date', _('Event date')),
+                ('order_date', _('Order date')),
+                ('invoice_date', _('Invoice date')),
+            ),
+        ),
+        'form_kwargs': dict(
+            label=_("Date of service"),
+            widget=forms.RadioSelect,
+            choices=(
+                ('auto', _('Automatic based on ticket-specific validity, membership validity, event series date, or event date)')),
+                ('auto_no_event', _('Automatic, but prefer invoice date over event date')),
+                ('event_date', _('Event date')),
+                ('order_date', _('Order date')),
+                ('invoice_date', _('Invoice date')),
+            ),
+            help_text=_("This controls what dates are shown on the invoice, but is especially important for "
+                        "electronic invoicing."),
+            required=True,
+        )
+    },
     'invoice_reissue_after_modify': {
         'default': 'False',
         'type': bool,