Implement payment backends and interaction

Advances #3 (closed)

aleksis/apps/tezor/models/invoice.py

 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
 from django.db import models
+from django.shortcuts import reverse
 from django.utils.translation import gettext_lazy as _
 
 from djmoney.models.fields import CurrencyField, MoneyField
@@ -45,9 +46,17 @@ class Invoice(BasePayment, PureDjangoModel):
     def get_purchased_items(self):
         return self.for_object.get_purchased_items()
 
+    def get_person(self):
+        if hasattr(self.for_object, "person"):
+            return self.for_object.person
+        elif hasattr(self.for_object, "get_person"):
+            return self.for_object.get_person()
+
+        return None
+
     class Meta:
         constraints = [
-            models.UniqueConstraint(fields=["transaction_id", "group"], name="number_uniq_per_group")
+            models.UniqueConstraint(fields=["number", "group"], name="number_uniq_per_group")
         ]
 
     @property
@@ -77,3 +86,9 @@ class Invoice(BasePayment, PureDjangoModel):
         })
 
         return TotalsTable(values)
+
+    def get_success_url(self):
+        return reverse("invoice_by_pk", kwargs={"pk": self.pk})
+
+    def get_failure_url(self):
+        return reverse("invoice_by_pk", kwargs={"pk": self.pk})