feat: handle unsubscribe

src/adapter/postgres.py

@@ -361,6 +361,46 @@ class Postgres(DatabaseBase):
         result = await self.session.execute(q)
         return result.scalar_one_or_none()
 
+    async def update_subscription(self, subscription: domain.Subscription) -> domain.Subscription:
+        await self.session.flush()
+        await self.session.refresh(subscription, ['placement', 'subscriber'])
+        return subscription
+
+    async def get_active_subscriptions_by_subscriber_and_channel(
+        self, subscriber_id: uuid.UUID, channel_telegram_id: int
+    ) -> list[domain.Subscription]:
+        q = (
+            select(domain.Subscription)
+            .join(domain.Placement, domain.Subscription.placement_id == domain.Placement.id)
+            .join(domain.TargetChannel, domain.Placement.target_channel_id == domain.TargetChannel.id)
+            .where(
+                domain.Subscription.subscriber_id == subscriber_id,
+                domain.TargetChannel.telegram_id == channel_telegram_id,
+                domain.Subscription.status == domain.SubscriptionStatus.ACTIVE,
+            )
+            .options(selectinload(domain.Subscription.placement), selectinload(domain.Subscription.subscriber))
+        )
+        result = await self.session.execute(q)
+        return list(result.scalars().all())
+
+    async def get_active_subscription_by_subscriber_and_channel(
+        self, subscriber_id: uuid.UUID, channel_telegram_id: int
+    ) -> domain.Subscription | None:
+        """Получить активную подписку пользователя на канал (должна быть только одна благодаря UNIQUE constraint)."""
+        q = (
+            select(domain.Subscription)
+            .join(domain.Placement, domain.Subscription.placement_id == domain.Placement.id)
+            .join(domain.TargetChannel, domain.Placement.target_channel_id == domain.TargetChannel.id)
+            .where(
+                domain.Subscription.subscriber_id == subscriber_id,
+                domain.TargetChannel.telegram_id == channel_telegram_id,
+                domain.Subscription.status == domain.SubscriptionStatus.ACTIVE,
+            )
+            .options(selectinload(domain.Subscription.placement), selectinload(domain.Subscription.subscriber))
+        )
+        result = await self.session.execute(q)
+        return result.scalar_one_or_none()
+
     async def create_placement_views_history(
         self, history: domain.PlacementViewsHistory
     ) -> domain.PlacementViewsHistory: