refactor(assets): modular architecture + async two-phase scanner & background seeder (#12621)

app/assets/database/queries/asset.py

@@ -0,0 +1,140 @@
+import sqlalchemy as sa
+from sqlalchemy import select
+from sqlalchemy.dialects import sqlite
+from sqlalchemy.orm import Session
+
+from app.assets.database.models import Asset, AssetReference
+from app.assets.database.queries.common import MAX_BIND_PARAMS, calculate_rows_per_statement, iter_chunks
+
+
+def asset_exists_by_hash(
+    session: Session,
+    asset_hash: str,
+) -> bool:
+    """
+    Check if an asset with a given hash exists in database.
+    """
+    row = (
+        session.execute(
+            select(sa.literal(True))
+            .select_from(Asset)
+            .where(Asset.hash == asset_hash)
+            .limit(1)
+        )
+    ).first()
+    return row is not None
+
+
+def get_asset_by_hash(
+    session: Session,
+    asset_hash: str,
+) -> Asset | None:
+    return (
+        (session.execute(select(Asset).where(Asset.hash == asset_hash).limit(1)))
+        .scalars()
+        .first()
+    )
+
+
+def upsert_asset(
+    session: Session,
+    asset_hash: str,
+    size_bytes: int,
+    mime_type: str | None = None,
+) -> tuple[Asset, bool, bool]:
+    """Upsert an Asset by hash. Returns (asset, created, updated)."""
+    vals = {"hash": asset_hash, "size_bytes": int(size_bytes)}
+    if mime_type:
+        vals["mime_type"] = mime_type
+
+    ins = (
+        sqlite.insert(Asset)
+        .values(**vals)
+        .on_conflict_do_nothing(index_elements=[Asset.hash])
+    )
+    res = session.execute(ins)
+    created = int(res.rowcount or 0) > 0
+
+    asset = (
+        session.execute(select(Asset).where(Asset.hash == asset_hash).limit(1))
+        .scalars()
+        .first()
+    )
+    if not asset:
+        raise RuntimeError("Asset row not found after upsert.")
+
+    updated = False
+    if not created:
+        changed = False
+        if asset.size_bytes != int(size_bytes) and int(size_bytes) > 0:
+            asset.size_bytes = int(size_bytes)
+            changed = True
+        if mime_type and asset.mime_type != mime_type:
+            asset.mime_type = mime_type
+            changed = True
+        if changed:
+            updated = True
+
+    return asset, created, updated
+
+
+def bulk_insert_assets(
+    session: Session,
+    rows: list[dict],
+) -> None:
+    """Bulk insert Asset rows with ON CONFLICT DO NOTHING on hash."""
+    if not rows:
+        return
+    ins = sqlite.insert(Asset).on_conflict_do_nothing(index_elements=[Asset.hash])
+    for chunk in iter_chunks(rows, calculate_rows_per_statement(5)):
+        session.execute(ins, chunk)
+
+
+def get_existing_asset_ids(
+    session: Session,
+    asset_ids: list[str],
+) -> set[str]:
+    """Return the subset of asset_ids that exist in the database."""
+    if not asset_ids:
+        return set()
+    found: set[str] = set()
+    for chunk in iter_chunks(asset_ids, MAX_BIND_PARAMS):
+        rows = session.execute(
+            select(Asset.id).where(Asset.id.in_(chunk))
+        ).fetchall()
+        found.update(row[0] for row in rows)
+    return found
+
+
+def update_asset_hash_and_mime(
+    session: Session,
+    asset_id: str,
+    asset_hash: str | None = None,
+    mime_type: str | None = None,
+) -> bool:
+    """Update asset hash and/or mime_type. Returns True if asset was found."""
+    asset = session.get(Asset, asset_id)
+    if not asset:
+        return False
+    if asset_hash is not None:
+        asset.hash = asset_hash
+    if mime_type is not None:
+        asset.mime_type = mime_type
+    return True
+
+
+def reassign_asset_references(
+    session: Session,
+    from_asset_id: str,
+    to_asset_id: str,
+    reference_id: str,
+) -> None:
+    """Reassign a reference from one asset to another.
+
+    Used when merging a stub asset into an existing asset with the same hash.
+    """
+    ref = session.get(AssetReference, reference_id)
+    if ref and ref.asset_id == from_asset_id:
+        ref.asset_id = to_asset_id
+
+    session.flush()