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 +359,9 @@ 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
+            extra_fields.append("tax_date")
         if not self.due_date:
             self.due_date = self.issue_date + datetime.timedelta(
                 days=self.get_due_delta()
@@ -415,7 +422,7 @@ def render_amount(self, amount: int | Decimal) -> str:
     @cached_property
     def exchange_rate_czk(self) -> Decimal:
         """Exchange rate from currency to CZK."""
-        return ExchangeRates.get(self.get_currency_display(), self.issue_date)
+        return ExchangeRates.get(self.get_currency_display(), self.tax_date)
 
     @cached_property
     def bank_account(self) -> BankAccountInfo:
@@ -424,7 +431,7 @@ def bank_account(self) -> BankAccountInfo:
     @cached_property
     def exchange_rate_eur(self) -> Decimal:
         """Exchange rate from currency to EUR."""
-        return ExchangeRates.get("EUR", self.issue_date) / self.exchange_rate_czk
+        return ExchangeRates.get("EUR", self.tax_date) / self.exchange_rate_czk
 
     @cached_property
     def total_items_amount(self) -> Decimal:
@@ -699,6 +706,7 @@ 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 +718,7 @@ def duplicate(  # noqa: PLR0913
             discount=self.discount,
             vat_rate=self.vat_rate,
             currency=self.currency,
+            tax_date=cast("datetime.date", tax_date),
             parent=self,
             prepaid=prepaid,
             extra=extra if extra is not None else self.extra,
@@ -863,7 +872,7 @@ def save(  # type: ignore[override]
                     self.unit_price = ExchangeRates.convert_from_eur(
                         self.package.price,
                         self.invoice.get_currency_display(),
-                        self.invoice.issue_date,
+                        self.invoice.tax_date,
                     )
                 extra_fields.append("unit_price")
             if not self.description:

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/invoices/tests.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from datetime import date, timedelta
 from decimal import Decimal
 from pathlib import Path
 from typing import cast
@@ -48,6 +49,8 @@ def create_invoice_base(  # noqa: PLR0913
         vat: str = "",
         kind: InvoiceKind = InvoiceKind.INVOICE,
         currency: Currency = Currency.EUR,
+        tax_date: date | None = None,
+        due_date: date | None = None,
     ) -> Invoice:
         return Invoice.objects.create(
             customer=self.create_customer(vat=vat),
@@ -58,6 +61,8 @@ def create_invoice_base(  # noqa: PLR0913
             category=InvoiceCategory.HOSTING,
             customer_reference=customer_reference,
             currency=currency,
+            tax_date=tax_date,
+            due_date=due_date,
         )
 
     def create_invoice_package(
@@ -85,6 +90,8 @@ def create_invoice(  # noqa: PLR0913
         customer_note: str = "",
         vat: str = "",
         kind: InvoiceKind = InvoiceKind.INVOICE,
+        tax_date: date | None = None,
+        due_date: date | None = None,
     ) -> Invoice:
         invoice = self.create_invoice_base(
             discount=discount,
@@ -93,6 +100,8 @@ def create_invoice(  # noqa: PLR0913
             customer_note=customer_note,
             vat=vat,
             kind=kind,
+            tax_date=tax_date,
+            due_date=due_date,
         )
         invoice.invoiceitem_set.create(
             description="Test item",
@@ -112,6 +121,18 @@ def validate_invoice(self, invoice: Invoice) -> None:
         xml_doc = etree.parse(invoice.xml_path)
         S3_SCHEMA.assertValid(xml_doc)
 
+    def test_dates(self) -> None:
+        invoice = self.create_invoice(vat="CZ8003280318")
+        self.assertEqual(invoice.tax_date, invoice.issue_date)
+        self.assertEqual(invoice.due_date, invoice.issue_date + timedelta(days=14))
+        tax_date = date(2020, 10, 10)
+        due_date = date(3030, 10, 10)
+        invoice = self.create_invoice(
+            vat="CZ8003280318", tax_date=tax_date, due_date=due_date
+        )
+        self.assertEqual(invoice.tax_date, tax_date)
+        self.assertEqual(invoice.due_date, due_date)
+
     def test_total(self) -> None:
         invoice = self.create_invoice(vat="CZ8003280318")
         self.assertEqual(invoice.total_amount, 100)

weblate_web/payments/backends.py

@@ -19,6 +19,7 @@
 
 from __future__ import annotations
 
+import datetime
 import re
 from decimal import Decimal
 from hashlib import sha256
@@ -31,6 +32,7 @@
 from django.db import transaction
 from django.shortcuts import redirect
 from django.utils.http import http_date
+from django.utils.timezone import make_aware
 from django.utils.translation import get_language, gettext, gettext_lazy
 
 from .models import Payment
@@ -386,6 +388,7 @@ 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.date(),
                 )
         else:
             category = InvoiceCategory.HOSTING
@@ -396,6 +399,7 @@ 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.date(),
                 currency=Currency.EUR,
                 prepaid=not proforma,
                 category=category,
@@ -536,7 +540,7 @@ def get_instructions(self) -> list[tuple[StrOrPromise, str]]:
         return instructions
 
     @classmethod
-    def fetch_payments(cls, from_date: str | None = None) -> None:  # noqa: C901, PLR0915
+    def fetch_payments(cls, from_date: str | None = None) -> None:  # noqa: C901, PLR0915, PLR0912
         from weblate_web.invoices.models import Invoice, InvoiceKind  # noqa: PLC0415
 
         tokens: list[str]
@@ -621,10 +625,23 @@ def fetch_payments(cls, from_date: str | None = None) -> None:  # noqa: C901, PL
                         continue
 
                     print(f"{invoice.number}: received payment")
+
                     # Instantionate backend (does SELECT FOR UPDATE)
                     backend = payment.get_payment_backend()
+
+                    # Sync payment date with the actual payment
+                    if backend.payment.created.date() != entry["date"]:
+                        # Make timezone aware datetime out of date object
+                        backend.payment.created = make_aware(
+                            datetime.datetime.combine(entry["date"], datetime.time.min)
+                        )
+                        # Saved later via backend.success()
+
                     # Store transaction details
                     backend.payment.details["transaction"] = entry
+                    # Saved later via backend.success()
+
+                    # Complete processing and save updated payment
                     backend.success()
                     processed = True
                     break