#!/usr/bin/env python

## imports
import json
import requests
import os, sys
import logging
import logging.handlers
from dotenv import load_dotenv

my_logger = logging.getLogger('MyLogger')
my_logger.setLevel(logging.DEBUG)

handler = logging.handlers.SysLogHandler(address = '/dev/log')
formatter = logging.Formatter("dyndns-update: %(message)s")
handler.setFormatter(formatter)

my_logger.addHandler(handler)


env_path = os.path.abspath ( os.path.join ( os.curdir, os.path.relpath('.env') ) )
load_dotenv(verbose=True, dotenv_path=env_path)

## constants

PDNS_API_BASE = os.getenv("PDNS_API_BASE")
PDNS_TOKEN = os.getenv("PDNS_TOKEN")
TMPFILE = '/tmp/lastIP'

def get_ip():
    r = requests.get('http://ipinfo.io')
    return (r.json()['ip'])

def set_record(zone, name, type, record):
  payload = {
    'rrsets': [
      {
        'name': name,
        'type': type,
        'ttl': 30,
        'changetype': "REPLACE",
        'records': [ record ]
      }
    ]
  }
  p = requests.patch(PDNS_API_BASE + 'zones/' + zone, headers={'X-API-KEY': PDNS_TOKEN}, json=payload)
  return  (p.status_code)


if len(sys.argv) > 2:
    if os.path.exists(TMPFILE):
        with open(TMPFILE) as file:
            try:
                lastIP=file.read()
            except:
                my_logger.critical('error reading ' + TMPFILE)
    else:
        lastIP = ''

    currentIP = get_ip()

    if lastIP == currentIP:
        my_logger.debug ('IP has not changed since last call')
        exit()

    record = {
        'disabled': False,
        'content': currentIP
        }

    if (set_record  (sys.argv[1], sys.argv[2]+'.', 'A', record) == 204):
        my_logger.debug('IP of ' + sys.argv[2] + ' successfully changed to ' + currentIP)

    with open(TMPFILE, 'w') as file:
        file.write(currentIP)

else:
  print('Updates IP record of NAME in ZONE to current IP from ipinfo.io\n\nUsage:\n' + sys.argv[0] + ' ZONE NAME')