feat(fc-cleanup): audit lifecycle service functions (start/apply/cancel) + tests — Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/services/cleanup_service.py

@@ -12,12 +12,14 @@ re-exports from this module and then delete the wrapper.
 """
 from __future__ import annotations
 
+from datetime import UTC, datetime
 from pathlib import Path
+from typing import Any
 
-from sqlalchemy import func, select
+from sqlalchemy import func, select, update
 from sqlalchemy.orm import Session
 
-from ..models import Artist, ImageRecord, Tag
+from ..models import Artist, ImageRecord, LibraryAuditRun, Tag
 from ..models.series_page import SeriesPage
 from ..models.tag import image_tag
 
@@ -409,3 +411,98 @@ def delete_min_dimension_violations(
         session, image_ids=list(ids), images_root=images_root,
     )
     return result["images_deleted"]
+
+
+# ---------------------------------------------------------------------------
+# Audit lifecycle (transparency + single_color async scans).
+# ---------------------------------------------------------------------------
+
+
+class AuditAlreadyRunning(Exception):
+    """Another audit_run is currently in status='running' — wait or
+    cancel it before starting a new one. Surfaces as HTTP 409 in the
+    /api/cleanup/audit POST endpoint."""
+
+
+class AuditNotReady(Exception):
+    """apply_audit_run called on an audit whose status is not 'ready'."""
+
+
+class ConfirmTokenMismatch(Exception):
+    """Operator-supplied confirm token did not match server-recomputed token."""
+
+
+_VALID_RULES = ("transparency", "single_color")
+
+
+def start_audit_run(
+    session: Session, *, rule: str, params: dict[str, Any],
+) -> int:
+    """Create a LibraryAuditRun row in status='running' and dispatch the
+    scan_library_for_rule Celery task. Returns the new audit_id.
+
+    Concurrent-runs guard: raises AuditAlreadyRunning if any audit_run
+    has status='running'. Operator must cancel or wait."""
+    if rule not in _VALID_RULES:
+        raise ValueError(f"unknown rule {rule!r}; expected one of {_VALID_RULES}")
+    existing = session.execute(
+        select(LibraryAuditRun.id).where(LibraryAuditRun.status == "running")
+    ).scalar_one_or_none()
+    if existing is not None:
+        raise AuditAlreadyRunning(existing)
+    audit = LibraryAuditRun(
+        rule=rule,
+        params=params,
+        status="running",
+        scanned_count=0,
+        matched_count=0,
+        matched_ids=[],
+    )
+    session.add(audit)
+    session.flush()
+    audit_id = audit.id
+    # Dispatch after flush so audit_id is populated; commit happens in
+    # the API handler so the audit row + dispatch are visible together.
+    from ..tasks.library_audit import scan_library_for_rule
+    scan_library_for_rule.delay(audit_id)
+    return audit_id
+
+
+def apply_audit_run(
+    session: Session, *, audit_id: int, confirm_token: str, images_root: Path,
+) -> int:
+    """Delete all images in audit_run.matched_ids after confirming token.
+    Marks audit status='applied'. Routes through delete_images so files
+    + cascading FK rows are handled uniformly."""
+    audit = session.execute(
+        select(LibraryAuditRun).where(LibraryAuditRun.id == audit_id)
+    ).scalar_one_or_none()
+    if audit is None:
+        raise ValueError(f"audit_run {audit_id} not found")
+    if audit.status != "ready":
+        raise AuditNotReady(audit.status)
+    expected = f"apply-audit-{audit_id}"
+    if confirm_token != expected:
+        raise ConfirmTokenMismatch(expected)
+    ids = list(audit.matched_ids or [])
+    deleted = 0
+    if ids:
+        result = delete_images(session, image_ids=ids, images_root=images_root)
+        deleted = result["images_deleted"]
+    session.execute(
+        update(LibraryAuditRun)
+        .where(LibraryAuditRun.id == audit_id)
+        .values(status="applied", finished_at=datetime.now(UTC))
+    )
+    return deleted
+
+
+def cancel_audit_run(session: Session, *, audit_id: int) -> None:
+    """Flip a running audit_run to 'cancelled'. The scan task checks
+    for status=='cancelled' between batches and exits cleanly."""
+    session.execute(
+        update(LibraryAuditRun)
+        .where(LibraryAuditRun.id == audit_id)
+        .where(LibraryAuditRun.status == "running")
+        .values(status="cancelled", finished_at=datetime.now(UTC))
+    )