#!/usr/bin/python3

import configparser
import copy
import json
import os
import smtplib
import subprocess
import sys
import time
from email.message import EmailMessage
from pprint import pprint

rundir=os.path.realpath(os.path.dirname(sys.argv[0]))
os.chdir(rundir)

sys.path.append(os.path.join(rundir,'sysbus/src'))
from sysbus import sysbus
from ovh import ovh


def load_conf():
    global zone_filename, log_filename
    global wan_hostname, zone_domain, zone_subdomain, zone_timeout
    global hosts_list, nat_list, pinhole_list
    global mail_from, mail_to, mail_ignore_list

    conf = configparser.ConfigParser(allow_no_value=True)
    conf.read('home.conf')

    zone_filename = conf['Files']['zonefile']
    log_filename = conf['Files']['logfile']

    wan_hostname = conf['Wan']['hostname'].lower()
    zone_domain = conf['Zone']['domain'].lower()
    zone_subdomain = conf['Zone']['subdomain'].lower()
    mail_from = conf['Mail']['from']
    mail_to   = conf['Mail']['to']
    mail_ignore_list = [ host.lower() for host in conf['MailIgnore'] ]
    mail_ignore_list = [ '.'.join([h, zone_subdomain]) if not h.endswith('.'+zone_subdomain) else h for h in mail_ignore_list ]

    hosts_list = [ host.lower() for host in conf['Hosts'] ]

    nat_list = {}
    for e in conf.items('PortsNat'):
        if e[1]:
            nat_list[e[0]] = e[1].split(',')
        else:
            nat_list[e[0]] = []

    pinhole_list = {}
    for e in conf.items('Firewall'):
        if e[1]:
            pinhole_list[e[0]] = e[1].split(',')
        else:
            pinhole_list[e[0]] = []
    zone_timeout = conf['Zone']['keep']
    if zone_timeout[-1] == 's':
        zone_timeout = int(zone_timeout[:-1])
    elif zone_timeout[-1] == 'm':
        zone_timeout = int(zone_timeout[:-1]) * 60
    elif zone_timeout[-1] == 'h':
        zone_timeout = int(zone_timeout[:-1]) * 3600
    elif zone_timeout[-1] == 'd':
        zone_timeout = int(zone_timeout[:-1]) * 86400
    else:
        zone_timeout = int(zone_timeout)


def ping(hostname):
    cmd = "ping -c1 -w3 %s" % hostname
    ret = subprocess.run(cmd.split(), stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    return 0 if ret.returncode else 1


def get_ipv6_hosts():
    r = sysbus.requete('Devices:get')

    ipv6_hosts = dict()
    for h in r['status']:
        if not 'IPv6Address' in h or not h['IPv6Address']:
            continue
        ns = {}
        for n in h['Names']:
            ns[n['Source']] = n['Name']
        hostname = h['Name']
        hostname = ns.get('mdns', hostname)
        hostname = ns.get('dhcp', hostname)
        hostname = ns.get('webui', hostname)
        hostname = hostname.lower()
        for a in h['IPv6Address']:
            if a['Scope'] != 'global' or a['Status'] != 'reachable':
                continue
            if not hostname in ipv6_hosts:
                ipv6_hosts[hostname] = []
            ipv6_hosts[hostname].append(a['Address'])
    return ipv6_hosts


def get_wan_addr():
    r = sysbus.requete('NMC:getWANStatus')
    wan = dict()
    wan['ipv4'] = r['data']['IPAddress']
    wan['ipv6'] = r['data']['IPv6Address']
    if wan['ipv4'] == '0.0.0.0':
        wan['ipv4'] = ''
    return wan


def full_name(host, domain):
    host = host.replace('_', '-')
    return '.'.join([host, domain])


def zone_add_entry(zone, prot, name, addr, stamp):
    #print('zone_add_entry: {} {} {} {}'.format(prot, name, addr, stamp))
    if not zone.get(prot):
        zone[prot] = {}
    if not zone[prot].get(name):
        zone[prot][name] = {}
    if not zone[prot][name].get(addr):
        zone[prot][name][addr] = { 'first': stamp }
    zone[prot][name][addr]['last'] = stamp


def populate_zone(zone, wan_hostname, wan_addr, hosts, hosts_list, hosts_nat, domain, stamp):

    wan_hostname = full_name(wan_hostname, domain)

    if not zone.get('A'):
        zone['A'] = {}
    if not zone.get('AAAA'):
        zone['AAAA'] = {}

    if wan_addr['ipv4'] != '':
        zone_add_entry(zone, 'A', wan_hostname, wan_addr['ipv4'], stamp)
        for host in hosts_nat:
            if hosts.get(host):
                zone_add_entry(zone, 'A', full_name(host, domain), wan_addr['ipv4'], stamp)

    if wan_addr['ipv6'] != '':
        zone_add_entry(zone, 'AAAA', wan_hostname, wan_addr['ipv6'], stamp)
        for host in hosts_list:
            for addr in hosts.get(host, []):
                zone_add_entry(zone, 'AAAA', full_name(host, domain), addr, stamp)

def process_zone(zone, stamp, grace_period):
    update = { 'add': [], 'delete': [] }
    for prot in zone:
        for name in zone[prot]:
            add = False
            for addr in zone[prot][name]:
                e = zone[prot][name][addr]
                if e['first'] == stamp:
                    update['add'].append([prot, name, addr])
                    add = True
            for addr in zone[prot][name]:
                e = zone[prot][name][addr]
                if add and e['last'] < stamp:
                    update['delete'].append([prot, name, addr])
                elif not add and stamp - e['last'] > grace_period:
                    update['delete'].append([prot, name, addr])

    if not update['add'] and not update['delete']:
        update = None
    return update


def read_zone_list(zone_filename):
    try:
        with open(zone_filename) as jsonfile:
            zone = json.load(jsonfile)
        return zone
    except FileNotFoundError:
        return {}


def write_zone_list(zone_filename, zone, update):
    zone = copy.deepcopy(zone)
    if update:
        for prot, name, addr in update['delete']:
            del zone[prot][name][addr]
            if not zone[prot][name]:
                del zone[prot][name]
    with open(zone_filename, 'w') as jsonfile:
        json.dump(zone, jsonfile, indent=2, sort_keys=True)


#def make_delete_zone_list(zone_list, prev_zone_list):
#    return make_update_zone_list(prev_zone_list, zone_list)
#
#
#def make_update_zone_list(zone_list, prev_zone_list):
#    update_zone_list = []
#    for entry in zone_list:
#        if not any(entry == x for x in prev_zone_list):
#            update_zone_list.append(entry)
#    return update_zone_list
#
#
#    for host,typefield,target in zone_list:
#        if not host in config:
#            config[host] = {}
#        if typefield in config[host]:
#            config[host][typefield] += '\n'+target
#        else:
#            config[host][typefield] = target
#    with open(zone_filename, 'w') as configfile:
#        config.write(configfile)


def log(msg):
    stamp = time.strftime("%Y-%m-%d %H:%M:%S")
    with open(log_filename, 'a') as logfile:
        for line in msg.split('\n'):
            logfile.write("%s - %s\n" % (stamp, msg))


def log_update_zone(update):
    op_str = { 'add': '', 'delete': '[DEL]' }

    for op in update:
        for prot, name, addr in update[op]:
            op = op_str.get(op, op)
            log('%5s %-20s %-6s %s' % (op, name, prot, addr))


def ovh_update_zone(domain, update):
    try:
        client = ovh.Client()

        for prot, name, addr in update['delete']:
            result = client.get('/domain/zone/%s/record' % domain,
                                fieldType=prot,
                                subDomain=name)
            for id in result:
                r = client.get('/domain/zone/%s/record/%d' % (domain, id))
                if r['fieldType'] == prot and r['target'] == addr:
                    print("OVH: delete entry for %s %s %s (#%s)" % (name, prot, addr, id))
                    client.delete('/domain/zone/%s/record/%d' % (domain, id))

        for prot, name, addr in update['add']:
            print("OVH: create entry for %s %s %s" % (name, prot, addr))
            client.post('/domain/zone/%s/record' % domain,
                    fieldType=prot,
                    subDomain=name,
                    target=addr,
                    ttl=60)

        print("OVH: Refresh zone %s" % domain)
        client.post('/domain/zone/%s/refresh' % domain)
        return True
    except:
        print('OVH update error\n')
        return False


def send_update_mail(mail_to, mail_from, zone_domain, update, mail_ignore_list, wan):
    okmail=False
    for op in update:
        for prot,name,addr in update[op]:
            if not name in mail_ignore_list:
                okmail = True
                break

    if not okmail:
        return

    print('Send email to %s' % mail_to)
    msg = EmailMessage()

    msg['Subject'] = "Livebox update in %s" % zone_domain
    msg['From'] = mail_from
    msg['To' ] = mail_to

    txt = "Livebox update\n\n"
    txt = txt + "WAN IPv4 : %s\n" % wan['ipv4']
    txt = txt + "WAN IPv6 : %s\n" % wan['ipv6']

    txt = txt + "\nZone %s has been updated:\n" % zone_domain

    for prot,name,addr in update['add']:
        txt = txt + "  %-20s %-4s %s\n" % (name,prot,addr)

    txt = txt + "\nRemoved entries:\n"

    for prot,name,addr in update['delete']:
        txt = txt + "  %-20s %-4s %s\n" % (name,prot,addr)

    txt = txt + '\n'

    msg.set_content(txt)

    s = smtplib.SMTP('localhost')
    s.send_message(msg)
    s.quit()
    #print(txt)


load_conf()

if not ping(wan_hostname):
    log("%s is down" % wan_hostname)
    sys.exit(0)

sysbus.load_conf()
r = sysbus.auth(False)
if not r:
    print('Error: cannot authenticate on livebox')
    sys.exit(1)

hosts = get_ipv6_hosts()
wan = get_wan_addr()

zone = read_zone_list(zone_filename)
stamp = int(time.time())
populate_zone(zone, wan_hostname, wan, hosts, hosts_list, nat_list, zone_subdomain, stamp)
update = process_zone(zone, stamp, zone_timeout)
if update:
    log_update_zone(update)

    success = ovh_update_zone(zone_domain, update)
    if success:
        send_update_mail(mail_to, mail_from, zone_domain, update, mail_ignore_list, wan)

write_zone_list(zone_filename, zone, update)