import requests
import os
import json
import ipaddress
import time
def recreate_cache(ip_server:str):
  print("[VYDNS] Obtaining public IP using server '"+ip_server+"'")
  ip=""
  try:
    ip=requests.get(ip_server,timeout=10).text.strip()
    ipaddress.ip_address(ip)
  except Exception as e:
    print("[VYDNS] Error: counldn't obtain IP or IP isn't valid. Exception: "+str(e))
    exit()
  print("[VYDNS] "+ip)
  cache={"ip":ip}
  with open("cache.json","w") as f:
    json.dump(cache,f)
  print("[VYDNS] Succesfully obtained IP.")
  return ip
def obtain_ip(ip_server:str):
  print("[VYDNS] Obtaining public IP using server '"+ip_server+"'")
  ip=""
  try:
    ip=requests.get(ip_server,timeout=10).text.strip()
    ipaddress.ip_address(ip)
  except Exception as e:
    print("[VYDNS] Error: counldn't obtain IP or IP isn't valid. Exception: "+str(e))
    exit()
  print("[VYDNS] "+ip)
  print("[VYDNS] Succesfully obtained IP.")
  return ip
def update_ip(ip:str,dns_endpoint:str,domains:str,username:str,password:str):
  print("[VYDNS] Updating "+str(len(domains))+" domains:")
  for d in domains:
    print("[VYDNS] Updating '"+d+"' :")
    params={
      "system":"dyndns",
      "hostname":d,
      "myip":ip
    }
    r=requests.get(dns_endpoint,params=params,auth=(username,password),timeout=10)
    print(r.text)
    if "good" in r.text or "nochg" in r.text:
      print("[VYDNS] Update OK.")
    else:
      print("[VYDNS] Update failed.")
conffile={}
if os.path.exists("config.json"):
  conffile=json.load(open("config.json","r"))
else:
  print("[VYDNS] Error: config file doesn't exist.")
  exit()
if ("ip_server" not in conffile) or ("dns_endpoint" not in conffile) or ("username" not in conffile) or ("password" not in conffile) or ("domains" not in conffile) or ("delay" not in conffile):
  print("[VYDNS] Error: config file isn't formatted as expected.")
  exit()
if (conffile["ip_server"]=="") or (conffile["dns_endpoint"]=="") or (conffile["username"]=="") or (conffile["password"]=="") or (conffile["delay"]<=0):
  print("[VYDNS] Error: one of the key is empty or invalid.")
  exit()
if (conffile["domains"]==[]):
  print("[VYDNS] Error: no domains provided.")
  exit()
while True:
  obtained_ip=""
  if not os.path.exists("cache.json"):
    print("[VYDNS] Cache file doesn't exist, recreating it.")
    obtained_ip=recreate_cache(conffile["ip_server"])
    update_ip(obtained_ip,conffile["dns_endpoint"],conffile["domains"],conffile["username"],conffile["password"])
    print("[VYDNS] Sleeping for "+str(conffile["delay"])+" seconds.")
    time.sleep(conffile["delay"])
    continue
  else:
    print("[VYDNS] Cache file exist, obtaining current IP for comparaison.")
    obtained_ip=obtain_ip(conffile["ip_server"])
    with open("cache.json","r") as f:
      cachefile=json.load(f)
    if cachefile["ip"]==obtained_ip:
      print("[VYDNS] According to cache file, IP didn't change.")
      print("[VYDNS] Sleeping for "+str(conffile["delay"])+" seconds.")
      time.sleep(conffile["delay"])
      continue
    else:
      print("[VYDNS] According to cache file, IP did changed.")
      update_ip(obtained_ip,conffile["dns_endpoint"],conffile["domains"],conffile["username"],conffile["password"])
      cache={"ip":obtained_ip}
      with open("cache.json","w") as f:
        json.dump(cache,f)
      print("[VYDNS] Sleeping for "+str(conffile["delay"])+" seconds.")
      time.sleep(conffile["delay"])
      continue