Update snapshots with sum db columns

nummi/main/models.py

@@ -4,7 +4,7 @@ import uuid
 
 from django.conf import settings
 from django.core.validators import FileExtensionValidator
-from django.db import models
+from django.db import models, transaction
 from django.forms import ModelForm
 from django.urls import reverse
 from django.utils.translation import gettext as _
@@ -64,9 +64,7 @@ class Account(CustomModel):
 class AccountModel(CustomModel):
     account = models.ForeignKey(
         Account,
-        on_delete=models.SET_NULL,
-        blank=True,
-        null=True,
+        on_delete=models.CASCADE,
         verbose_name=_("Account"),
     )
 
@@ -117,6 +115,20 @@ class Snapshot(AccountModel):
     start_value = models.DecimalField(
         max_digits=12, decimal_places=2, default=0, verbose_name=_("Start value")
     )
+    diff = models.DecimalField(
+        max_digits=12,
+        decimal_places=2,
+        default=0,
+        verbose_name=_("Difference"),
+        editable=False,
+    )
+    sum = models.DecimalField(
+        max_digits=12,
+        decimal_places=2,
+        default=0,
+        verbose_name=_("Transaction difference"),
+        editable=False,
+    )
     file = models.FileField(
         upload_to=snapshot_path,
         validators=[FileExtensionValidator(["pdf"])],
@@ -135,8 +147,18 @@ class Snapshot(AccountModel):
             if _prever.file and _prever.file != self.file:
                 pathlib.Path(_prever.file.path).unlink(missing_ok=True)
 
+        with transaction.atomic():
+            for trans in self.transaction_set.all():
+                trans.save()
+
+        self.diff = self.value - self.start_value
+        self.sum = self.transaction_set.aggregate(sum=models.Sum("value")).get("sum", 0)
         super().save(*args, **kwargs)
 
+    def update_sum(self):
+        self.sum = self.transaction_set.aggregate(sum=models.Sum("value")).get("sum", 0)
+        super().save()
+
     def delete(self, *args, only_super=False, **kwargs):
         if self.file:
             self.file.delete()
@@ -147,24 +169,6 @@ class Snapshot(AccountModel):
     def get_delete_url(self):
         return reverse("del_snapshot", kwargs={"pk": self.pk})
 
-    @property
-    def pos(self):
-        return (
-            self.transactions.filter(value__gt=0).aggregate(sum=models.Sum("value"))[
-                "sum"
-            ]
-            or 0
-        )
-
-    @property
-    def neg(self):
-        return (
-            self.transactions.filter(value__lt=0).aggregate(sum=models.Sum("value"))[
-                "sum"
-            ]
-            or 0
-        )
-
     class Meta:
         ordering = ["-date"]
         verbose_name = _("Statement")
@@ -209,6 +213,7 @@ class Transaction(CustomModel):
 
     def save(self, *args, **kwargs):
         self.account = self.snapshot.account
+        self.snapshot.update_sum()
         super().save(*args, **kwargs)
 
     def __str__(self):