ref: remove signals in favor of save() override

app/base/models/account.py

@@ -21,10 +21,10 @@ class Account(models.Model):
     def __str__(self):
         return f"{self.user}'s Konto"
 
-    # def change_balance(self, amount):
-    #     self.balance = self.balance - amount
-    #     self.save()
-    #     return True
+    def update_balance(self, amount: 'Decimal') -> None:
+        if amount:
+            self.balance += amount
+            self.save()
 
     # def lock(self):
     #     self.locked = True

app/base/models/booking.py

@@ -5,6 +5,7 @@ from django.urls import reverse
 
 from app.base.forms.fields import DateTimeField, TextField
 from app.base.forms.utils import datetime_now
+from app.base.models.transaction import Transaction
 
 from typing import TYPE_CHECKING
 if TYPE_CHECKING:
@@ -42,11 +43,14 @@ class Booking(models.Model):
             if self.end_time else '')
 
     def save(self, *args, **kwargs):
-        # update last_visit time of all involved persons
         prev = Booking.objects.get(pk=self.pk) if self.pk else None
 
         rv = super().save(*args, **kwargs)
 
+        # update Transaction
+        Transaction.upsertFromBooking(self)
+
+        # update last_visit time of all involved persons
         if prev and prev.user != self.user:
             prev.user.update_last_visit(None)
         if not prev or prev.user != self.user or \

app/base/models/person.py

@@ -59,6 +59,7 @@ class Person(models.Model):
         if self._state.adding:
             self.created = date.today()
             self.last_visit = date.today()
+            Account.objects.create(user=self)
         return super().save(*args, **kwargs)
 
     @property

app/base/models/transaction.py

@@ -38,4 +38,37 @@ class Transaction(models.Model):
     def save(self, *args, **kwargs):
         if self._state.adding:
             self.time_stamp = datetime_now()
+            self.account.update_balance(self.amount)
+        elif self.pk:  # basically an "else", but just to be sure
+            prev = Transaction.objects.get(pk=self.pk)
+            self.account.update_balance(self.amount - prev.amount)
+
         return super().save(*args, **kwargs)
+
+    def delete(self, *args, **kwargs):
+        self.account.update_balance(-self.amount)
+        return super().delete(*args, **kwargs)
+
+    @staticmethod
+    def upsertFromBooking(booking: 'Booking'):
+        amount = booking.calculated_price
+        should_exist = booking.end_time and amount
+        description = f'{booking.type.label} ({booking.duration or 0} Min)'
+
+        # Create or update existing Transaction
+        transaction = Transaction.objects.filter(booking=booking).first()
+        if transaction:
+            if should_exist:
+                transaction.amount = -amount
+                transaction.description = description
+                transaction.save()
+            else:
+                transaction.delete()
+
+        elif should_exist:
+            Transaction.objects.create(
+                account=booking.user.account,
+                amount=-amount,
+                description=description,
+                booking=booking,
+            )