feat(recurring-transaction): update unpaid transactions info when recurring transaction is updated

app/apps/api/serializers/transactions.py

@@ -120,6 +120,11 @@ class RecurringTransactionSerializer(serializers.ModelSerializer):
         instance.create_upcoming_transactions()
         return instance
 
+    def update(self, instance, validated_data):
+        instance = super().update(instance, validated_data)
+        instance.update_unpaid_transactions()
+        return instance
+
 
 class TransactionSerializer(serializers.ModelSerializer):
     category = TransactionCategoryField(required=False)

app/apps/transactions/forms.py

@@ -767,5 +767,7 @@ class RecurringTransactionForm(forms.ModelForm):
         instance = super().save(**kwargs)
         if is_new:
             instance.create_upcoming_transactions()
+        else:
+            instance.update_unpaid_transactions()
 
         return instance

app/apps/transactions/models.py

@@ -540,3 +540,33 @@ class RecurringTransaction(models.Model):
             recurring_transaction.save(
                 update_fields=["last_generated_date", "last_generated_reference_date"]
             )
+
+    def update_unpaid_transactions(self):
+        """
+        Updates all unpaid transactions associated with this RecurringTransaction.
+
+        Only unpaid transactions (`is_paid=False`) are modified. Updates fields like
+        amount, description, category, notes, and many-to-many relationships (tags, entities).
+        """
+        unpaid_transactions = self.transactions.filter(is_paid=False)
+
+        for existing_transaction in unpaid_transactions:
+            # Update fields based on RecurringTransaction
+            existing_transaction.amount = self.amount
+            existing_transaction.description = self.description
+            existing_transaction.category = self.category
+            existing_transaction.notes = self.notes
+
+            # Update many-to-many relationships
+            existing_transaction.tags.set(self.tags.all())
+            existing_transaction.entities.set(self.entities.all())
+
+            # Save updated transaction
+            existing_transaction.save()
+
+    def delete_unpaid_transactions(self):
+        """
+        Deletes all unpaid transactions associated with this RecurringTransaction.
+        """
+        today = timezone.localdate(timezone.now())
+        self.transactions.filter(is_paid=False, date__gt=today).delete()