#!/usr/bin/python

### Configuration ###

postgresql_dsn = "dbname=dynette user=dynette password=myPassword"
conf_file = '/etc/bind/named.conf.local'    # Include this filename in '/etc/bind/named.conf'
zone_dir  = '/var/lib/bind/'                # Do not forget the trailing '/'
subs_urls = ['https://dyndns.yunohost.org']  # 127.0.0.1 if you install subscribe server locally
ns0       = 'ns0.yunohost.org'          # Name servers
ns1       = 'ns1.yunohost.org'
rname     = 'hostmaster@yunohost.org' # Responsible person (https://tools.ietf.org/html/rfc1035#section-3.3.13)

allowed_operations = {
            '.'                  : ['A', 'AAAA', 'TXT', 'MX'],
            '*.'                 : ['A', 'AAAA'],
            'pubsub.'            : ['A', 'AAAA', 'CNAME'],
            'muc.'               : ['A', 'AAAA', 'CNAME'],
            'vjud.'              : ['A', 'AAAA', 'CNAME'],
            '_xmpp-client._tcp.' : ['SRV'],
            '_xmpp-server._tcp.' : ['SRV'],
            'mail._domainkey.'   : ['TXT'],
            '_dmarc.'            : ['TXT']
}


### Script ###

import os
import json
import psycopg2
from urllib import urlopen


# Get master key
master_key_path = os.path.join(os.path.dirname(__file__), 'master.key')
master_key = open(master_key_path).read().rstrip()

# Bind configuration
lines = ['// Generated by Dynette CRON']

with psycopg2.connect(postgresql_dsn) as postgresql_connection:
    with postgresql_connection.cursor() as psql:
        # Loop through Dynette servers
        for url in subs_urls:

            lines.extend([
                    'key dynette. {',
                    '       algorithm hmac-md5;',
                    '       secret "'+ master_key +'";',
                    '};',
            ])

            # Get available DynDNS domains
            domains = json.loads(str(urlopen(url +'/domains').read()))
            for domain in domains:

                # Create zone database if not present
                if not os.path.exists(zone_dir + domain +'.db'):
                    db_lines = [
                        '$ORIGIN .',
                        '$TTL 10 ; 10 seconds',
                        domain+'.   IN SOA  '+ ns0 +'. '+ rname +'. (',
                        '                                18         ; serial',
                        '                                10800      ; refresh (3 hours)',
                        '                                3600       ; retry (1 hour)',
                        '                                604800     ; expire (1 week)',
                        '                                10         ; minimum (10 seconds)',
                        '                                )',
                        '$TTL 3600       ; 1 hour',
                        '                        NS      '+ ns0 +'.',
                        '                        NS      '+ ns1 +'.',
                        '',
                        '$ORIGIN '+ domain +'.',
                    ]
                    with open(zone_dir + domain +'.db', 'w') as zone:
                        for line in db_lines:
                            zone.write(line + '\n')

                lines.extend([
                        'zone "'+ domain +'" {',
                        '   type master;',
                        '   file "'+ zone_dir + domain +'.db"; ',
                        '   update-policy {',
                        '       grant dynette. wildcard *.'+ domain +'. ANY;',
                ])

                # Get registered sub-domains
                result = json.loads(str(urlopen(url +'/all/'+ domain).read()))
                for entry in result:
                    for subd, type in allowed_operations.items():
                        if subd == '.': subd = ''
                        lines.append('       grant '+ entry['subdomain'] +'. name '+ subd + entry['subdomain'] +'. ' + ' '.join(type) +';')

                lines.extend([
                        '   };',
                        '};'
                        '',
                ])

                for entry in result:
                    lines.extend([
                        'key '+ entry['subdomain'] +'. {',
                        '       algorithm ' + entry['key_algo'] + ';',
                        '       secret "'+ entry['public_key'] +'";',
                        '};',
                    ])

        # look in the job queue if we have tasks to handle
        need_rewrite = False
        need_bind9_cache_flush = False

        # DataMapper convert table names to lower cases and add a "s" at the
        # end
        # consume all available tasks at once to merge them and avoir doing
        # useless jobs
        for task in psql.execute("SELECT task FROM jobqueues ORDER BY id ASC;"):
            task = task[0]
            if task == "conf_rewrite":
                need_rewrite = True
            elif task == "bind9_cache_flush":
                need_bind9_cache_flush = True

        # we have consume all the jobs, flush it
        # because we are in a SQL transaction we won't have situation where a
        # job could be added just after we read them all
        psql.execute("DELETE FROM jobqueues;")

        # update bind9 zone
        if need_rewrite:
            # Backup old Bind configuration file.
            os.system('cp '+ conf_file +' '+ conf_file +'.back')

            # Write Bind configuration file.
            with open(conf_file, 'w') as zone:
                zone.write('\n'.join(lines) + '\n')

            # Restore ownership
            os.system('chown -R bind:bind '+ zone_dir +' '+ conf_file)

            # Reload Bind
            if os.system('/usr/sbin/rndc reload') == 0:
                exit(0)
            else:
                os.system('cp '+ conf_file +' '+ conf_file +'.bad')
                os.system('cp '+ conf_file +'.back '+ conf_file)
                os.system('/usr/sbin/rndc reload')
                print("An error occured ! Please check daemon.log and your conf.bad")
                exit(1)

        # flush bind9 cache (mostly because we got a hmac-sha512 key migration
        if need_bind9_cache_flush:
            os.system('/usr/sbin/rndc flush')
            os.system('/usr/sbin/rndc reload')