"""utils."""

from os import path
from uuid import uuid4

from backfill.constants import MOUNT_PATH


def generate_local_filepath(key: str, default_extension: str = ".csv") -> str:
    """Return a local filepath to save an s3 file to."""
    _, extension = path.splitext(key)
    if not extension:
        extension = default_extension
    filename = f"{uuid4()}{extension}"

    return path.join(MOUNT_PATH, filename)