import shutil
from pathlib import Path

from fastapi import UploadFile

from backend.config import settings


def ensure_upload_dir() -> Path:
    target = Path(settings.upload_dir)
    target.mkdir(parents=True, exist_ok=True)
    return target


def save_upload(upload_file: UploadFile) -> Path:
    target_dir = ensure_upload_dir()
    target_path = target_dir / upload_file.filename
    with target_path.open("wb") as buffer:
        shutil.copyfileobj(upload_file.file, buffer)
    return target_path


def save_upload_for_job(job_id: int, seq: int, upload_file: UploadFile) -> Path:
    """Save file with unique path under upload_dir/job_id/ to avoid overwrites."""
    base = ensure_upload_dir() / str(job_id)
    base.mkdir(parents=True, exist_ok=True)
    name = upload_file.filename or "file"
    target_path = base / f"{seq}_{name}"
    with target_path.open("wb") as buffer:
        shutil.copyfileobj(upload_file.file, buffer)
    return target_path