add download service

backend/app/openings_downloader/services/storage_tracker.py

@@ -0,0 +1,58 @@
+from sqlalchemy import select, func
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from ..db_models import AnimeTheme
+from ..schemas import StorageStatsResponse
+from ..config import downloader_settings
+from ...db_models import Opening
+
+
+class StorageTrackerService:
+    """Service for tracking S3 storage usage from DB (without scanning S3)."""
+
+    def __init__(self, db: AsyncSession):
+        self.db = db
+
+    async def get_stats(self) -> StorageStatsResponse:
+        """Calculate storage stats from database."""
+
+        # Sum file sizes from downloaded themes
+        result = await self.db.execute(
+            select(func.coalesce(func.sum(AnimeTheme.file_size_bytes), 0))
+            .where(AnimeTheme.file_size_bytes.isnot(None))
+        )
+        used_bytes = result.scalar() or 0
+
+        # Count openings in the main Opening table
+        result = await self.db.execute(
+            select(func.count(Opening.id))
+        )
+        openings_count = result.scalar() or 0
+
+        limit_bytes = downloader_settings.s3_storage_limit_bytes
+        available_bytes = max(0, limit_bytes - used_bytes)
+        used_percent = (used_bytes / limit_bytes * 100) if limit_bytes > 0 else 0
+
+        return StorageStatsResponse(
+            used_bytes=used_bytes,
+            limit_bytes=limit_bytes,
+            used_percent=round(used_percent, 2),
+            available_bytes=available_bytes,
+            can_download=used_bytes < limit_bytes,
+            openings_count=openings_count,
+        )
+
+    async def get_estimated_queue_size(self) -> int:
+        """Get estimated size of pending downloads in queue."""
+        from ..db_models import DownloadTask, DownloadStatus
+
+        result = await self.db.execute(
+            select(func.coalesce(func.sum(DownloadTask.estimated_size_bytes), 0))
+            .where(DownloadTask.status.in_([
+                DownloadStatus.QUEUED,
+                DownloadStatus.DOWNLOADING,
+                DownloadStatus.CONVERTING,
+                DownloadStatus.UPLOADING,
+            ]))
+        )
+        return result.scalar() or 0