Initial release — MediaTracker v1.0

Dockerized media library scanner for NAS drives.
Identifies movies and series from filenames, fetches posters
via the public IMDB suggestion API (no key required), and
exposes a dark-themed web UI with multilingual search support.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/scheduler.py

@@ -0,0 +1,95 @@
+"""
+scheduler.py — Background scan scheduler using APScheduler.
+"""
+
+import logging
+import threading
+
+from apscheduler.schedulers.background import BackgroundScheduler
+
+from config import Settings
+from scanner import (
+    create_scan_record,
+    has_any_scan_completed,
+    run_full_scan,
+    run_incremental_scan,
+)
+
+logger = logging.getLogger(__name__)
+
+_scheduler: BackgroundScheduler | None = None
+_scan_lock = threading.Lock()
+_active_scan_id: int | None = None
+
+
+def get_active_scan_id() -> int | None:
+    return _active_scan_id
+
+
+def is_scan_running() -> bool:
+    return _active_scan_id is not None
+
+
+def _run_scan_protected(scan_type: str, settings: Settings) -> int | None:
+    """Try to acquire lock and run a scan. Returns scan_id or None if already running."""
+    global _active_scan_id
+    if not _scan_lock.acquire(blocking=False):
+        logger.warning("Scan already in progress — skipping %s scan request", scan_type)
+        return None
+
+    scan_id = create_scan_record(scan_type)
+    _active_scan_id = scan_id
+    logger.info("Scan %s started (id=%d)", scan_type, scan_id)
+
+    def _run():
+        global _active_scan_id
+        try:
+            if scan_type == "full":
+                run_full_scan(settings, scan_id)
+            else:
+                run_incremental_scan(settings, scan_id)
+        finally:
+            _active_scan_id = None
+            _scan_lock.release()
+            logger.info("Scan %s finished (id=%d)", scan_type, scan_id)
+
+    thread = threading.Thread(target=_run, daemon=True, name=f"scan-{scan_type}-{scan_id}")
+    thread.start()
+    return scan_id
+
+
+def trigger_full_scan(settings: Settings) -> int | None:
+    return _run_scan_protected("full", settings)
+
+
+def trigger_incremental_scan(settings: Settings) -> int | None:
+    return _run_scan_protected("incremental", settings)
+
+
+def start_scheduler(settings: Settings) -> None:
+    global _scheduler
+
+    _scheduler = BackgroundScheduler(timezone="UTC")
+    _scheduler.add_job(
+        func=lambda: trigger_incremental_scan(settings),
+        trigger="interval",
+        hours=settings.scan_interval_hours,
+        id="incremental_scan",
+        replace_existing=True,
+    )
+    _scheduler.start()
+    logger.info(
+        "Scheduler started — incremental scan every %d hour(s)",
+        settings.scan_interval_hours,
+    )
+
+    # Trigger initial full scan if the database has never been scanned
+    if not has_any_scan_completed():
+        logger.info("No prior completed scan found — launching initial full scan")
+        trigger_full_scan(settings)
+
+
+def stop_scheduler() -> None:
+    if _scheduler and _scheduler.running:
+        _scheduler.shutdown(wait=False)
+        logger.info("Scheduler stopped")