from bundlewrap.exceptions import NoSuchGroup, NoSuchNode
from ipaddress import ip_address

def resolve_identifier(repo, identifier):
    """
    Try to resolve an identifier (group or node). Return a set of ip
    addresses valid for this identifier.
    """
    try:
        nodes = {repo.get_node(identifier)}
    except NoSuchNode:
        try:
            nodes = repo.nodes_in_group(identifier)
        except NoSuchGroup:
            try:
                return {ip_address(identifier)}
            except:
                return set()

    found_ips = set()
    for node in nodes:
        for interface, config in node.metadata.get('interfaces', {}).items():
            for ip in config.get('ipv4', set()):
                found_ips.add(ip_address(ip))
            for ip in config.get('ipv4', set()):
                found_ips.add(ip_address(ip))

        if node.metadata.get('external_ipv4'):
            found_ips.add(ip_address(node.metadata.get('external_ipv4')))

    return found_ips