from typing import List

from .net_cidr_cidr_info import cidr_info
from .net_ipv4 import format_ipv4, parse_ipv4


def cidr_hosts(cidr: str, max_count: int) -> List[str]:
    """Every usable host address of an IPv4 block, in order, for a sweep.

    The limit is required, not optional: a typo of /8 for /28 is sixteen
    million addresses, and the caller should hear about it before allocating
    them.
    """
    if isinstance(max_count, bool) or not isinstance(max_count, int) or max_count < 1:
        raise ValueError("maxCount must be a whole number of at least 1, received %r" % (max_count,))
    info = cidr_info(cidr)
    if info.host_count > max_count:
        raise ValueError("%s has %d hosts, more than maxCount %d" % (info.cidr, info.host_count, max_count))
    first = parse_ipv4(info.first_host)
    return [format_ipv4(first + i) for i in range(info.host_count)]