Some optimizations to trade_offers to reduce loading times

trades/models.py

@@ -1,11 +1,39 @@
 from django.db import models
 from django.core.exceptions import ValidationError
-from django.db.models import Q
+from django.db.models import Q, Count, Prefetch, F, Sum
 import hashlib
 from cards.models import Card
 from accounts.models import FriendCode
+class TradeOfferManager(models.Manager):
+
+    def get_queryset(self):
+        queryset = super().get_queryset().select_related("initiated_by", "initiated_by__user")
+        queryset = queryset.prefetch_related(
+            Prefetch(
+                "trade_offer_want_cards",
+                queryset=TradeOfferWantCard.objects.select_related("card").annotate(
+                    total_quantity=Sum("quantity"),
+                    total_accepted=Sum("qty_accepted")
+                ).order_by("total_quantity", "id")
+            ),
+            Prefetch(
+                "trade_offer_have_cards",
+                queryset=TradeOfferHaveCard.objects.select_related("card").annotate(
+                    total_quantity=Sum("quantity"),
+                    total_accepted=Sum("qty_accepted")
+                ).order_by("total_quantity", "id")
+            ),
+            Prefetch(
+                "acceptances",
+                queryset=TradeAcceptance.objects.select_related("accepted_by", "accepted_by__user", "requested_card", "offered_card")
+            ),
+        ).order_by("-updated_at")
+        return queryset
+
 
 class TradeOffer(models.Model):
+    objects = TradeOfferManager()
+
     id = models.AutoField(primary_key=True)
     is_closed = models.BooleanField(default=False, db_index=True)
     hash = models.CharField(max_length=9, editable=False)