Add model MembershipPayment

aleksis/apps/vereinsmeier/models.py

+from decimal import Decimal
+
 from django.db import models
 from django.utils.translation import gettext_lazy as _
 
 from djmoney.models.fields import MoneyField
 from localflavor.generic.models import BICField, IBANField
+from payments import PurchasedItem
 
+from aleksis.apps.tezor.models.base import Client
+from aleksis.apps.tezor.models.invoice import Invoice, InvoiceGroup
 from aleksis.core.mixins import ExtensibleModel
 from aleksis.core.models import Group, Person
 
@@ -121,3 +126,63 @@ class Membership(ExtensibleModel):
     sepa_mandate = models.OneToOneField(
         SEPAMandate, verbose_name=_("Linked SEPA mandate"), null=True, on_delete=models.SET_NULL
     )
+
+
+class MembershipPayment(ExtensibleModel):
+
+    membership = models.ForeignKey(
+        Membership, verbose_name=_("Membership"), on_delete=models.CASCADE
+    )
+    due_date = models.DateField(verbose_name=_("Due date"))
+    begin = models.DateField(verbose_name=_("Start of payed membership"))
+    end = models.DateField(verbose_name=_("End of payed membership"))
+
+    fees = MoneyField(verbose_name=_("Membership fees"), default=0, max_digits=8, decimal_places=2)
+
+    def get_invoice(self):
+        # FIXME Maybe do not hard-code this
+        client, __ = Client.objects.get_or_create(name="Teckids e.V.")
+        group, __ = InvoiceGroup.objects.get_or_create(
+            name="Mitgliedsbeiträge und Spenden",
+            client=client,
+            defaults={
+                "template_name": "paweljong/invoice_pdf.html",
+            },
+        )
+
+        invoice, __ = Invoice.objects.get_or_create(
+            for_content_type=ContentType.objects.get_for_model(self),
+            for_object_id=self.pk,
+            defaults={
+                "group": group,
+                "number": f"MSP-{self.begin.strftime('%Y-%m-%d')}-{self.id}",
+                "currency": "EUR",
+                "total": self.fees,
+                "tax": 0,
+                "description": _("Membership fee of {}").format(self.membership.person),
+                "billing_first_name": self.membership.person.first_name,
+                "billing_last_name": self.membership.person.last_name,
+                "billing_address_1": f"{self.membersip.person.street} {self.membersip.person.housenumber}",
+                "billing_city": self.membersip.person.place,
+                "billing_postcode": self.person.membersip.postal_code,
+                "billing_email": self.membersip.person.email,
+            },
+        )
+
+        return invoice
+
+    def get_purchased_items(self):
+        # FIXME Maybe do not hard-code the tax rate and currency
+        # First, return main amount
+        yield PurchasedItem(
+            name="Membership fee",
+            quantity=1,
+            price=Decimal(self.event.cost),
+            currency="EUR",
+            sku="MEMBERSHIP",
+            tax_rate=0,
+        )
+
+    class Meta:
+        verbose_name = _("Membership payment")
+        verbose_name_plural = _("Membership payments")