"""Seed configured header matches on otherwise unconfigured mailing lists."""

from json import loads

from mailman.interfaces.mailinglist import IHeaderMatchList


RULES = loads({{ mailman_empty_list_header_matches | to_json | to_json }})


def apply(mlist):
    """Add all configured rules if *mlist* has no header matches."""
    header_matches = IHeaderMatchList(mlist)
    existing_count = len(header_matches)
    if existing_count:
        print('SKIPPED {} existing_header_matches={}'.format(
            mlist.fqdn_listname, existing_count))
        return

    for rule in RULES:
        header_matches.append(
            rule['header'],
            rule['pattern'],
            chain=rule.get('action'),
            tag=rule.get('tag'))

    print('CHANGED {} added_header_matches={}'.format(
        mlist.fqdn_listname, len(RULES)))