feat: 假单列表全局2分钟打乱一次，全用户顺序一致

Co-authored-by: Cursor <cursoragent@cursor.com>

orders/services/fake_order_pool.py

@@ -4,15 +4,17 @@ from datetime import timedelta
 from decimal import Decimal
 
 from django.core.exceptions import ObjectDoesNotExist
+from django.db import transaction
 from django.utils import timezone
 from rest_framework.response import Response
 
 from backend.utils import fmt_datetime, pick_leixing_id
 from jituan.services.club_context import resolve_effective_club_id
 from jituan.services.dashou_exam import user_has_active_member
-from orders.models import FakeGrabOrder
+from orders.models import FakeGrabOrder, FakeGrabOrderShuffleState
 
 DEFAULT_DISPATCHER_AVATAR = 'beijing/morentouxiang.jpg'
+SHUFFLE_STATE_PK = 1
 
 
 def dashou_should_use_fake_pool(user):
@@ -46,6 +48,49 @@ def _random_display_time_str():
     return fmt_datetime(dt)
 
 
+def _resolve_shuffle_epoch():
+    """
+    全用户共用一条打乱状态（id=1）：
+    - 距上次打乱 >= IntervalSeconds：更新 LastShuffleTime，进入新打乱窗口
+    - 否则：沿用上次打乱时刻，本窗口内顺序不变
+    返回用于固定顺序的 epoch 时间戳；若应使用库表顺序则返回 None。
+    """
+    now = timezone.now()
+    with transaction.atomic():
+        state, created = FakeGrabOrderShuffleState.objects.select_for_update().get_or_create(
+            pk=SHUFFLE_STATE_PK,
+            defaults={
+                'LastShuffleTime': now - timedelta(days=1),
+                'IntervalSeconds': 120,
+            },
+        )
+        interval = max(1, int(state.IntervalSeconds or 120))
+        elapsed = (now - state.LastShuffleTime).total_seconds()
+        if created or elapsed >= interval:
+            state.LastShuffleTime = now
+            state.save(update_fields=['LastShuffleTime', 'UpdateTime'])
+            return int(state.LastShuffleTime.timestamp())
+        return None
+
+
+def _order_fake_rows(rows, shuffle_epoch):
+    """shuffle_epoch 有值：按全局 epoch 固定打乱；None：按库表 SortOrder/CreateTime。"""
+    items = list(rows)
+    if shuffle_epoch is None:
+        items.sort(
+            key=lambda r: (
+                -(r.SortOrder or 0),
+                r.CreateTime or timezone.datetime.min.replace(tzinfo=timezone.utc),
+                r.id or 0,
+            ),
+        )
+        return items
+    base = sorted(items, key=lambda r: (r.id or 0, r.OrderID or ''))
+    rng = random.Random(shuffle_epoch)
+    rng.shuffle(base)
+    return base
+
+
 def _format_fake_row(row, display_time=None):
     """字段与 DashouDingdanHuoquView 真实单列表保持一致。"""
     # 平台单用 tupian、商家单用 tupian + sj_avatar，统一默认头像
@@ -97,8 +142,8 @@ def build_fake_order_pool_response(request):
     if leixing_id is not None:
         qs = qs.filter(ProductTypeID=leixing_id)
 
-    rows = list(qs)
-    random.shuffle(rows)
+    shuffle_epoch = _resolve_shuffle_epoch()
+    rows = _order_fake_rows(qs, shuffle_epoch)
 
     total = len(rows)
     offset = (page - 1) * page_size