feat: deals viewer mode and links for viewers

services/status.py

@@ -1,8 +1,8 @@
 from typing import Optional
 
-from sqlalchemy import select, and_, func
+from sqlalchemy import select, and_, func, exists, or_
 
-from models import CardStatus, Card
+from models import CardStatus, Card, CardStatusHistory
 from schemas.status import *
 from services.base import BaseService
 
@@ -106,6 +106,18 @@ class StatusService(BaseService):
         statuses[-2].is_finishing = True
         statuses[-1].is_finishing = False
 
+    async def _status_has_history(self, status_id: int) -> bool:
+        stmt = (
+            select(exists(CardStatusHistory))
+            .where(
+                or_(
+                    CardStatusHistory.to_status_id == status_id,
+                    CardStatusHistory.from_status_id == status_id,
+                )
+            )
+        )
+        return (await self.session.scalars(stmt)).first()
+
     async def delete_status(self, status_id: int) -> DeleteStatusResponse:
         status = await self._get_status_by_id(status_id)
         if not status:
@@ -119,7 +131,8 @@ class StatusService(BaseService):
             await self._set_finishing_flag_to_prev_status(status)
 
         count_deals = await self._count_deals(status_id)
-        if count_deals == 0:
+        exist_in_history = await self._status_has_history(status_id)
+        if count_deals == 0 and not exist_in_history:
             await self.session.delete(status)
         else:
             status.is_deleted = True