Move unspread fertilization entries on variety change

backend/apps/fertilizer/services.py

@@ -3,9 +3,10 @@ from decimal import Decimal
 from django.db import transaction
 from django.db.models import Sum
 
+from apps.materials.stock_service import create_reserves_for_plan
 from apps.materials.models import StockTransaction
 from apps.workrecords.services import sync_spreading_work_record
-from .models import FertilizationEntry, SpreadingSessionItem
+from .models import FertilizationEntry, FertilizationPlan, SpreadingSessionItem
 
 
 def sync_actual_bags_for_pairs(year, field_fertilizer_pairs):
@@ -56,3 +57,51 @@ def sync_stock_uses_for_spreading_session(session):
             fertilization_plan=None,
             spreading_item=item,
         )
+
+
+@transaction.atomic
+def move_unspread_entries_for_variety_change(change):
+    moved_count = 0
+    old_variety_id = change.old_variety_id
+    new_variety = change.new_variety
+    if old_variety_id is None or new_variety is None:
+        return 0
+
+    old_plans = (
+        FertilizationPlan.objects
+        .filter(
+            year=change.year,
+            variety_id=old_variety_id,
+            entries__field_id=change.field_id,
+            entries__actual_bags__isnull=True,
+        )
+        .distinct()
+        .prefetch_related('entries')
+    )
+
+    for old_plan in old_plans:
+        entries_to_move = list(
+            old_plan.entries.filter(
+                field_id=change.field_id,
+                actual_bags__isnull=True,
+            ).order_by('id')
+        )
+        if not entries_to_move:
+            continue
+
+        new_plan = FertilizationPlan.objects.create(
+            name=f'{change.year}年度 {new_variety.name} 施肥計画（品種変更移動）',
+            year=change.year,
+            variety=new_variety,
+            calc_settings=old_plan.calc_settings,
+        )
+
+        FertilizationEntry.objects.filter(
+            id__in=[entry.id for entry in entries_to_move]
+        ).update(plan=new_plan)
+
+        create_reserves_for_plan(old_plan)
+        create_reserves_for_plan(new_plan)
+        moved_count += len(entries_to_move)
+
+    return moved_count