Optimize user account pages

counter/models.py

@@ -20,7 +20,7 @@ import random
 import string
 from datetime import date, datetime, timedelta
 from datetime import timezone as tz
-from typing import Tuple
+from typing import Self, Tuple
 
 from dict2xml import dict2xml
 from django.conf import settings
@@ -585,6 +585,23 @@ class Counter(models.Model):
         )["total"]
 
 
+class RefillingQuerySet(models.QuerySet):
+    def annotate_total(self) -> Self:
+        """Annotate the Queryset with the total amount.
+
+        The total is just the sum of the amounts for each row.
+        If no grouping is involved (like in most queries),
+        this is just the same as doing nothing and fetching the
+        `amount` attribute.
+
+        However, it may be useful when there is a `group by` clause
+        in the query, or when other models are queried and having
+        a common interface is helpful (e.g. `Selling.objects.annotate_total()`
+        and `Refilling.objects.annotate_total()` will both have the `total` field).
+        """
+        return self.annotate(total=Sum("amount"))
+
+
 class Refilling(models.Model):
     """Handle the refilling."""
 
@@ -613,6 +630,8 @@ class Refilling(models.Model):
     )
     is_validated = models.BooleanField(_("is validated"), default=False)
 
+    objects = RefillingQuerySet.as_manager()
+
     class Meta:
         verbose_name = _("refilling")
 
@@ -657,6 +676,15 @@ class Refilling(models.Model):
         super().delete(*args, **kwargs)
 
 
+class SellingQuerySet(models.QuerySet):
+    def annotate_total(self) -> Self:
+        """Annotate the Queryset with the total amount of the sales.
+
+        The total is considered as the sum of (unit_price * quantity).
+        """
+        return self.annotate(total=Sum(F("unit_price") * F("quantity")))
+
+
 class Selling(models.Model):
     """Handle the sellings."""
 
@@ -703,6 +731,8 @@ class Selling(models.Model):
     )
     is_validated = models.BooleanField(_("is validated"), default=False)
 
+    objects = SellingQuerySet.as_manager()
+
     class Meta:
         verbose_name = _("selling")