import time

import dns.exception
import dns.resolver
from dyn.tm.errors import DynectCreateError
from dyn.tm.session import DynectSession
from dyn.tm.zones import Node, Zone
from flask import current_app
from tld import get_tld


def get_dynect_session():
    dynect_session = DynectSession(
        current_app.config.get('ACME_DYN_CUSTOMER_NAME', ''),
        current_app.config.get('ACME_DYN_USERNAME', ''),
        current_app.config.get('ACME_DYN_PASSWORD', ''),
    )
    return dynect_session


def _has_dns_propagated(name, token):
    txt_records = []
    try:
        dns_resolver = dns.resolver.Resolver()
        dns_resolver.nameservers = ['8.8.8.8']
        dns_response = dns_resolver.query(name, 'TXT')
        for rdata in dns_response:
            for txt_record in rdata.strings:
                txt_records.append(txt_record.decode("utf-8"))
    except dns.exception.DNSException:
        return False

    for txt_record in txt_records:
        if txt_record == token:
            return True

    return False


def wait_for_dns_change(change_id, account_number=None):
    fqdn, token = change_id
    while True:
        status = _has_dns_propagated(fqdn, token)
        current_app.logger.debug("Record status for fqdn: {}: {}".format(fqdn, status))
        if status:
            break
        time.sleep(20)
    return


def create_txt_record(domain, token, account_number):
    get_dynect_session()
    zone_name = get_tld('http://' + domain)
    zone_parts = len(zone_name.split('.'))
    node_name = '.'.join(domain.split('.')[:-zone_parts])
    fqdn = "{0}.{1}".format(node_name, zone_name)
    zone = Zone(zone_name)
    try:
        zone.add_record(node_name, record_type='TXT', txtdata="\"{}\"".format(token), ttl=5)
    except DynectCreateError:
        delete_txt_record(None, None, domain, token)
        zone.add_record(node_name, record_type='TXT', txtdata="\"{}\"".format(token), ttl=5)
    node = zone.get_node(node_name)
    zone.publish()
    current_app.logger.debug("TXT record created: {0}".format(fqdn))
    change_id = (fqdn, token)
    return change_id


def delete_txt_record(change_id, account_number, domain, token):
    get_dynect_session()
    if not domain:
        current_app.logger.debug("delete_txt_record: No domain passed")
        return

    zone_name = get_tld('http://' + domain)
    zone_parts = len(zone_name.split('.'))
    node_name = '.'.join(domain.split('.')[:-zone_parts])
    fqdn = "{0}.{1}".format(node_name, zone_name)

    zone = Zone(zone_name)
    node = Node(zone_name, fqdn)
    all_txt_records = node.get_all_records_by_type('TXT')
    for txt_record in all_txt_records:
        if txt_record.txtdata == ("{}".format(token)):
            current_app.logger.debug("Deleting TXT record name: {0}".format(fqdn))
            txt_record.delete()
    zone.publish()