fix - improve excel reapopnse on transaction

apps/herd/management/commands/rebuild_herd_livestock_counts.py

@@ -0,0 +1,57 @@
+from collections import defaultdict
+
+from django.core.management.base import BaseCommand
+from django.db import transaction
+from django.db.models.aggregates import Count
+
+from apps.herd.models import Herd
+from apps.livestock.models import LiveStock
+
+
+class Command(BaseCommand):
+    help = "Rebuild heavy/light counts for all herds"
+    BATCH_SIZE = 2000
+
+    def handle(self, *args, **options):
+        self.stdout.write("🔄 Rebuilding herd livestock counts...")
+
+        self.stdout.write("📊 Aggregating livestock data...")
+        livestock_stats = (
+            LiveStock.objects
+            .filter(archive=False, herd__isnull=False)
+            .values('herd_id', 'weight_type')
+            .annotate(cnt=Count('id'))
+        )
+
+        herd_map = defaultdict(lambda: {"H": 0, "L": 0})
+
+        for row in livestock_stats:
+            herd_map[row['herd_id']][row['weight_type']] = row['cnt']
+
+        self.stdout.write(f"✅ Aggregated {len(herd_map)} herds")
+
+        self.stdout.write("✍️ Updating herds in batches...")
+
+        herd_ids = list(herd_map.keys())
+
+        for i in range(0, len(herd_ids), self.BATCH_SIZE):
+            batch_ids = herd_ids[i:i + self.BATCH_SIZE]
+
+            herds = Herd.objects.filter(id__in=batch_ids)
+
+            for herd in herds:
+                counts = herd_map.get(herd.id, {})
+                herd.heavy_livestock_number = counts.get("H", 0)
+                herd.light_livestock_number = counts.get("L", 0)
+
+            with transaction.atomic():
+                Herd.objects.bulk_update(
+                    herds,
+                    ['heavy_livestock_number', 'light_livestock_number']
+                )
+
+            self.stdout.write(
+                f"✔ Updated {i + len(batch_ids)} / {len(herd_ids)} herds"
+            )
+
+            self.stdout.write("🎉 Herd livestock counts rebuilt successfully.")