feat: fetch views manually and worker

src/usecase/views/fetch_views_manually.py

@@ -0,0 +1,65 @@
+import datetime
+import logging
+from typing import TYPE_CHECKING
+
+from src import domain, dto
+
+if TYPE_CHECKING:
+    from .. import Usecase
+
+log = logging.getLogger(__name__)
+
+
+async def fetch_views_manually(self: 'Usecase', input: dto.FetchViewsInputManually) -> dto.FetchViewsManuallyOutput:
+    async with self.database.transaction():
+        purchase = await self.database.get_purchase(input.user_id, input.purchase_id)
+        if not purchase:
+            raise domain.PurchaseNotFound(input.purchase_id)
+
+        if not purchase.ad_post_url:
+            return dto.FetchViewsManuallyOutput(
+                purchase_id=purchase.id,
+                views_count=None,
+                views_availability=domain.PostViewsAvailability.UNAVAILABLE,
+                fetched_at=datetime.datetime.now(datetime.UTC),
+                error_message='No ad_post_url specified',
+            )
+
+        views_count = await self.telegram_parser.get_post_views(purchase.ad_post_url)
+        fetched_at = datetime.datetime.now(datetime.UTC)
+
+        if views_count:
+            purchase.views_count = views_count
+            purchase.views_availability = domain.PostViewsAvailability.AVAILABLE
+            purchase.last_views_fetch_at = fetched_at
+            await self.database.update_purchase(purchase)
+
+            snapshot = domain.ViewsSnapshot(
+                purchase_id=purchase.id,
+                views_count=views_count,
+                fetched_at=fetched_at,
+            )
+            await self.database.create_views_snapshot(snapshot)
+
+            log.info('Views fetched for purchase %s: %d', purchase.id, views_count)
+
+            return dto.FetchViewsManuallyOutput(
+                purchase_id=purchase.id,
+                views_count=views_count,
+                views_availability=domain.PostViewsAvailability.AVAILABLE,
+                fetched_at=fetched_at,
+            )
+
+        purchase.views_availability = domain.PostViewsAvailability.UNAVAILABLE
+        purchase.last_views_fetch_at = fetched_at
+        await self.database.update_purchase(purchase)
+
+        log.warning('Failed to fetch views for purchase %s', purchase.id)
+
+        return dto.FetchViewsManuallyOutput(
+            purchase_id=purchase.id,
+            views_count=None,
+            views_availability=domain.PostViewsAvailability.UNAVAILABLE,
+            fetched_at=fetched_at,
+            error_message='Failed to fetch views from Telegram API',
+        )