from decouple import config
import datetime
import logging
import MySQLdb as m
import dns.resolver

def read_config():
    zones_str = config('ZONES', default='example.com')
    zones = zones_str.split(',')
    dbhost = config('DB_HOST', 'localhost')
    dbport = int(config('DB_PORT', '3306'))
    dbdb = config('DB_DB', 'pdns')
    dbuser = config('DB_USER', 'test')
    dbpass = config('DB_PASS', 'testpass')
    master = config('DNS_MASTER', 'wile')
    return (zones,dbhost, dbport, dbuser, dbpass, dbdb, master)


def main():
    (zones, host, port, username, password, database, myname) = read_config()
    db = m.connect(host, username, password, database)
    for zone in zones:
        logging.debug(f"checking zone {zone}")
        # try to resolve dnskey.{zone} on all nameservers
        # dammit, my testserver is running on a weird port
        r = dns.resolver.Resolver()
        ns_str = config('NAMESERVERS', 'localhost:10053')
        nsarr = ns_str.split(',')
        expected = None
        for ns in nsarr:
            try:
                answer = r.resolve(qname=zone, rdtype='DNSKEY', tcp=False, search=ns)
                if not expected:
                    expected = answer.rrset.to_text()
                    expected = expected[expected.find('IN ')]
                else:
                    answer_text = answer.rrset.to_text()
                    answer_text = answer_text[answer_text.find('IN ')]
                    if answer_text != expected:
                        logging.debug(f"'{answer_text}' differs from '{expected}', bumping SOA record for {zone}")
                        # I'm very confident this is more complicated than it needs to be...
                        db.query(f"""SELECT id,content FROM records WHERE type='SOA' AND name='{zone}'""")
                        result = db.store_result()
                        row = result.fetch_row()
                        (id,content) = row[0]
                        carr = content.split()
                        newdatestr = datetime.datetime.today().strftime("%Y%m%d01")
                        if newdatestr[:8] == carr[2][:8]:
                            count = int(carr[2][8:])
                            newcount = count + 1
                            newdatestr = f"{newdatestr[:8]}{newcount:02d}"
                        carr[2] = newdatestr
                        db.query(f"""UPDATE records SET content = '{' '.join(carr)}' WHERE id={id}""")
                        db.commit()
            except:
                logging.error(f"{zone} has no DNSKEY")

if __name__ == "__main__":
    logging.basicConfig(format='%(asctime)s %(name)-12s %(levelname)-8s %(message)s',
                    datefmt='%Y-%m-%d %H:%M:%S',
                    filename=config('LOG_FILENAME', './dnssec-fix.log'),
                    level=config('LOG_LEVEL', 'DEBUG'))

    main()