import configparser
import os
import sys

import xml.etree.ElementTree as ET
from requests import get

BASE_URL = 'https://www.namesilo.com/api'
UPDATE_URL = '{base}/dnsUpdateRecord?version=1&type=xml&key={key}' \
    '&domain={domain}&rrid={rrid}&' \
    'rrhost={host}&rrvalue={new_value}&rrttl=7207'
LIST_URL = '{base}/dnsListRecords?version=1&type=xml&key={key}&domain={domain}'

EVERYDAY_IP_SERVICE = 'https://tool.everyday.in.th/ip?format=text'

'''Updater procedure
1. Getch a new public IP
2. Get a namesilo's DNS
3. check if 1 & 2 are different, then Update
'''


def get_public_ip():
    '''Get current public IP

    return IP or None
    '''
    res = get(EVERYDAY_IP_SERVICE)
    if res.status_code != 200:
        return None
    ip = res.text.strip().replace('::ffff:', '')
    return ip


def get_namesilo_dns(key, domain, target_host):
    res = get(LIST_URL.format(base=BASE_URL, key=key, domain=domain))
    if res.status_code != 200:
        return None
    tree = ET.fromstring(res.text.strip())
    for i in tree.iter('resource_record'):
        host = i.find('./host').text
        if host == target_host:
            return {
                'rrid': i.find('./record_id').text,
                'value': i.find('./value').text,
                'host': host,
            }
            break
    return {}


def update_namesilo_data(key, domain, rrid, subdomain, new_value):
    res = get(UPDATE_URL.format(
            base=BASE_URL,
            key=key,
            domain=domain,
            rrid=rrid,
            host=subdomain,
            new_value=new_value))
    if res.status_code != 200:
        return None
    return True


def main():
    config = configparser.ConfigParser()
    config.read('settings.conf')
    domain = config['default']['domain']
    subdomain = config['default']['subdomain']
    api_key = os.environ.get('NAMESILO_API', None)
    if not api_key:
        if 'namesilo_api' not in config['default']:
            print('NAMESILO_API not found.')
            sys.exit()
        api_key = config['default']['namesilo_api']
    print('KEY: {}...'.format(api_key[:3]))
    target = '{}.{}'.format(subdomain, domain)
    print('TARGET: {}'.format(target))
    public_ip = get_public_ip()
    print('PUBLIC IP: {}..'.format(public_ip[:-5]))
    namesilo_data = get_namesilo_dns(api_key, domain, target)
    if not namesilo_data:
        print('NAMESILO API service is down or target not found')
        sys.exit()

    curr_ip = namesilo_data['value']
    if curr_ip == public_ip:
        print('Current value is okay. No need to do anything')
        sys.exit()

    rrid = namesilo_data['rrid']
    result = update_namesilo_data(api_key, domain, rrid, subdomain, public_ip)
    if not result:
        print('Updating process failed.')
        sys.exit()

    print('Updated to a new IP: {} from {}'.format(public_ip, curr_ip))


if __name__ == '__main__':
    main()