feat(invoice): separate date of taxable supply

Needed for accounting reasons.

Author: nijel

weblate_web/invoices/migrations/0021_invoice_tax_date.py

@@ -0,0 +1,21 @@
+# Generated by Django 5.2.8 on 2025-12-10 14:44
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("invoices", "0020_invoice_customer_note"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="invoice",
+            name="tax_date",
+            field=models.DateField(
+                blank=True,
+                help_text="Date of taxable supply, keep blank for issue date",
+                null=True,
+            ),
+        ),
+    ]

weblate_web/invoices/migrations/0022_set_tax_date.py

@@ -0,0 +1,19 @@
+# Generated by Django 5.2.8 on 2025-12-10 14:45
+
+from django.db import migrations
+from django.db.models import F
+
+
+def migrate(apps, schema_editor) -> None:
+    Invoice = apps.get_model("invoices", "Invoice")
+    Invoice.objects.filter(tax_date=None).update(tax_date=F("issue_date"))
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("invoices", "0021_invoice_tax_date"),
+    ]
+
+    operations = [
+        migrations.RunPython(migrate, migrations.RunPython.noop, elidable=True),
+    ]

weblate_web/invoices/migrations/0023_alter_invoice_tax_date.py

@@ -0,0 +1,20 @@
+# Generated by Django 5.2.8 on 2025-12-10 14:55
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("invoices", "0022_set_tax_date"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="invoice",
+            name="tax_date",
+            field=models.DateField(
+                blank=True,
+                help_text="Date of taxable supply, keep blank for issue date",
+            ),
+        ),
+    ]

weblate_web/invoices/models.py

@@ -285,6 +285,10 @@ class Invoice(models.Model):  # noqa: PLR0904
         blank=True,
         help_text="Due date / Quote validity, keep blank unless specific terms are needed",
     )
+    tax_date = models.DateField(
+        blank=True,
+        help_text="Date of taxable supply, keep blank for issue date",
+    )
 
     kind = models.IntegerField(choices=InvoiceKind)
     category = models.IntegerField(
@@ -355,6 +359,8 @@ def save(  # type: ignore[override]
         if self.extra is None:
             self.extra = {}
         extra_fields: list[str] = []
+        if not self.tax_date:
+            self.tax_date = self.issue_date
         if not self.due_date:
             self.due_date = self.issue_date + datetime.timedelta(
                 days=self.get_due_delta()
@@ -699,6 +705,7 @@ def duplicate(  # noqa: PLR0913
         extra: dict[str, int] | None = None,
         customer_reference: str | None = None,
         customer_note: str | None = None,
+        tax_date: datetime.date | None = None,
     ) -> Invoice:
         """Create a final invoice from draft/proforma upon payment."""
         invoice = Invoice.objects.create(
@@ -710,6 +717,7 @@ def duplicate(  # noqa: PLR0913
             discount=self.discount,
             vat_rate=self.vat_rate,
             currency=self.currency,
+            tax_date=tax_date,
             parent=self,
             prepaid=prepaid,
             extra=extra if extra is not None else self.extra,

weblate_web/invoices/templates/invoice-template.html

@@ -247,7 +247,7 @@ <h2>Issued by</h2>
             <th>Contact</th>
           </tr>
           <tr>
-            <td>{{ invoice.issue_date|date }}</td>
+            <td>{{ invoice.tax_date|date }}</td>
             <td>21668027</td>
             <td>Michal Čihař</td>
             <td>C 52324/KSUL Krajský soud v Ústí nad Labem</td>

weblate_web/payments/backends.py

@@ -386,6 +386,7 @@ def generate_invoice(self, *, proforma: bool = False) -> None:
                 invoice = self.payment.draft_invoice.duplicate(
                     kind=invoice_kind,
                     prepaid=not proforma,
+                    tax_date=self.payment.created,
                 )
         else:
             category = InvoiceCategory.HOSTING
@@ -396,6 +397,7 @@ def generate_invoice(self, *, proforma: bool = False) -> None:
                 kind=invoice_kind,
                 customer=self.payment.customer,
                 vat_rate=self.payment.customer.vat_rate,
+                tax_date=self.payment.created,
                 currency=Currency.EUR,
                 prepaid=not proforma,
                 category=category,
@@ -623,6 +625,8 @@ def fetch_payments(cls, from_date: str | None = None) -> None:  # noqa: C901, PL
                     print(f"{invoice.number}: received payment")
                     # Instantionate backend (does SELECT FOR UPDATE)
                     backend = payment.get_payment_backend()
+                    # Sync payment date with the actual payment
+                    backend.payment.created = entry["date"]
                     # Store transaction details
                     backend.payment.details["transaction"] = entry
                     backend.success()