"""Helpers para subidas temporales desde la app desktop."""
from __future__ import annotations

import os
import tempfile
from contextlib import contextmanager
from typing import Iterator

from fastapi import UploadFile


@contextmanager
def temp_upload_path(upload: UploadFile, *, suffix: str | None = None) -> Iterator[str]:
  """Guarda un UploadFile en disco temporal y lo elimina al salir."""
  ext = suffix
  if ext is None and upload.filename:
    _, ext = os.path.splitext(upload.filename)
  if not ext:
    ext = ".bin"

  fd, path = tempfile.mkstemp(suffix=ext)
  os.close(fd)
  try:
    upload.file.seek(0)
    with open(path, "wb") as handle:
      while True:
        chunk = upload.file.read(1024 * 1024)
        if not chunk:
          break
        handle.write(chunk)
    yield path
  finally:
    try:
      os.unlink(path)
    except OSError:
      pass