import ipaddress
import re

_LABEL_RE = re.compile(r"^[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?$")


def normalize_hostname(value: str, allow_wildcard: bool = True) -> tuple[str, bool]:
    hostname = value.strip().rstrip(".").lower()
    wildcard = False

    if allow_wildcard and hostname.startswith("*."):
        wildcard = True
        hostname = hostname[2:]

    if not hostname or len(hostname) > 253:
        raise RuntimeError(f"Invalid hostname: {value!r}")

    for label in hostname.split("."):
        if not _LABEL_RE.match(label):
            raise RuntimeError(f"Invalid hostname: {value!r}")

    normalized = f"*.{hostname}" if wildcard else hostname
    return normalized, wildcard


def normalize_ipv4(value: str, label: str = "IP") -> str:
    try:
        addr = ipaddress.ip_address(value.strip())
    except ValueError as exc:
        raise RuntimeError(f"{label}: {value!r} is not a valid IP address") from exc

    if addr.version != 4:
        raise RuntimeError(f"{label}: only IPv4 is currently supported")

    return str(addr)