utils.py

"""Utils."""

import argparse
from pathlib import Path
from typing import Optional


def existing_file_path(value: str, allow_none=False) -> Optional[Path]:
    if not value or value.lower() == "none":
        if allow_none:
            return None
        else:
            raise argparse.ArgumentTypeError("`none` is not allowed here.")

    path = Path(value)

    if path.is_dir():
        raise argparse.ArgumentTypeError(f"{value} is a directory. A file is required.")

    elif not path.is_file():
        raise argparse.ArgumentTypeError(f"{value} does not exist.")

    return path