import threading, uuid

_jobs = {}

@mcp.tool()
def start_batch_job(input_dir: str, output_dir: str = "", mode: str = "auto") -> dict:
    """Start a background job that de-identifies all DICOM/image files
    in a directory. Returns immediately with a job_id. Use get_job_status
    to check progress, do not wait synchronously.
    """
    job_id = uuid.uuid4().hex[:8]
    _jobs[job_id] = {"job_id": job_id, "state": "queued",
                     "processed": 0, "total": None,
                     "decisions": {}, "errors": []}
    threading.Thread(
        target=_batch_worker, args=(job_id, input_dir, output_dir),
        daemon=True,
    ).start()
    return {"status": "started", "job_id": job_id,
            "next_step": f"Call get_job_status with job_id '{job_id}'."}