def mask_mobile(value: str | None) -> str:
    if not value:
        return ""
    if len(value) < 7:
        return "***"
    return f"{value[:3]}****{value[-4:]}"


def mask_email(value: str | None) -> str:
    if not value or "@" not in value:
        return ""
    name, _, domain = value.partition("@")
    if not name or not domain:
        return ""
    return f"{name[:1]}***@{domain}"


def mask_id_card(value: str | None) -> str:
    if not value:
        return ""
    if len(value) < 8:
        return "***"
    return f"{value[:4]}**********{value[-4:]}"