import re


DOMAIN_NAME_REGEX = r'^[a-zA-Z0-9._-]+$' # could be a FQDN, but also just a name


def validate_and_split_path_and_domain_name(path_or_dn: str) -> list[str] | None:
    """
    Splits a string along slashes and validates each fragment.

    Args:
        path_or_dn: Input string that may contain slashes (Some path, name, FQDN or a combination of them)

    Returns:
        List of validated fragments in original order, or None if validation fails
    """
    import re

    # Split the input by slashes
    fragments = [frag for frag in path_or_dn.strip().split('/')]

    # Validate each fragment contains only allowed characters
    validated_fragments = []

    for frag in fragments:
        if not re.match(DOMAIN_NAME_REGEX, frag):
            return None

        validated_fragments.append(frag)

    # Return the list of validated fragments or None if any failed validation
    # NOTE: validated_fragments could be falsy if input was empty or only slashes
    return validated_fragments if validated_fragments else None