#!/usr/bin/python
# -*- coding: UTF-8 -*-

# Copyright (c) 2016, Adfinis SyGroup AG
# Tobias Rueetschi <tobias.ruetschi@adfinis-sygroup.ch>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
#


from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.univention_umc import (
    umc_module_for_add,
    umc_module_for_edit,
    ldap_search,
    base_dn,
)


DOCUMENTATION = '''
---
module: udm_dns_zone
version_added: "2.2"
author: "Tobias Rueetschi (@2-B)"
short_description: Manage dns zones on a univention corporate server
description:
    - "This module allows to manage dns zones on a univention corporate server (UCS).
       It uses the python API of the UCS to create a new object or edit it."
requirements:
    - Python >= 2.6
options:
    state:
        required: false
        default: "present"
        choices: [ present, absent ]
        description:
            - Whether the dns zone is present or not.
    type:
        required: true
        choices: [ forward_zone, reverse_zone ]
        description:
            - Define if the zone is a forward or reverse DNS zone.
    zone:
        required: true
        description:
            - DNS zone name, e.g. C(example.com).
    nameserver:
        required: false
        description:
            - List of appropriate name servers. Required if C(state=present).
    interfaces:
        required: false
        description:
            - List of interface IP addresses, on which the server should
              response this zone. Required if C(state=present).

    refresh:
        required: false
        default: 3600
        description:
            - Interval before the zone should be refreshed.
    retry:
        required: false
        default: 1800
        description:
            - Interval that should elapse before a failed refresh should be retried.
    expire:
        required: false
        default: 604800
        description:
            - Specifies the upper limit on the time interval that can elapse before the zone is no longer authoritative.
    ttl:
        required: false
        default: 600
        description:
            - Minimum TTL field that should be exported with any RR from this zone.

    contact:
        required: false
        default: ''
        description:
            - Contact person in the SOA record.
    mx:
        required: false
        default: []
        description:
            - List of MX servers. (Must declared as A or AAAA records).
'''


EXAMPLES = '''
# Create a DNS zone on a UCS
- udm_dns_zone: zone=example.com
                type=forward_zone
                nameserver=['ucs.example.com']
                interfaces=['192.168.1.1']
'''


RETURN = '''# '''


def convert_time(time):
    """Convert a time in seconds into the biggest unit"""
    units = [
        (24 * 60 * 60 , 'days'),
        (60 * 60      , 'hours'),
        (60           , 'minutes'),
        (1            , 'seconds'),
    ]

    if time == 0:
        return ('0', 'seconds')
    for unit in units:
        if time >= unit[0]:
            return ('{}'.format(time // unit[0]), unit[1])


def main():
    module = AnsibleModule(
        argument_spec = dict(
            type        = dict(required=True,
                               type='str'),
            zone        = dict(required=True,
                               aliases=['name'],
                               type='str'),
            nameserver  = dict(default=[],
                               type='list'),
            interfaces  = dict(default=[],
                               type='list'),
            refresh     = dict(default=3600,
                               type='int'),
            retry       = dict(default=1800,
                               type='int'),
            expire      = dict(default=604800,
                               type='int'),
            ttl         = dict(default=600,
                               type='int'),
            contact     = dict(default='',
                               type='str'),
            mx          = dict(default=[],
                               type='list'),
            state       = dict(default='present',
                               choices=['present', 'absent'],
                               type='str')
        ),
        supports_check_mode=True,
        required_if = ([
            ('state', 'present', ['nameserver', 'interfaces'])
        ])
    )
    type        = module.params['type']
    zone        = module.params['zone']
    nameserver  = module.params['nameserver']
    interfaces  = module.params['interfaces']
    refresh     = module.params['refresh']
    retry       = module.params['retry']
    expire      = module.params['expire']
    ttl         = module.params['ttl']
    contact     = module.params['contact']
    mx          = module.params['mx']
    state       = module.params['state']
    changed     = False

    obj = list(ldap_search(
        '(&(objectClass=dNSZone)(zoneName={}))'.format(zone),
        attr=['dNSZone']
    ))

    exists = bool(len(obj))
    container = 'cn=dns,{}'.format(base_dn())
    dn = 'zoneName={},{}'.format(zone, container)
    if contact == '':
        contact = 'root@{}.'.format(zone)

    if state == 'present':
        try:
            if not exists:
                obj = umc_module_for_add('dns/{}'.format(type), container)
            else:
                obj = umc_module_for_edit('dns/{}'.format(type), dn)
            obj['zone']         = zone
            obj['nameserver']   = nameserver
            obj['a']            = interfaces
            obj['refresh']      = convert_time(refresh)
            obj['retry']        = convert_time(retry)
            obj['expire']       = convert_time(expire)
            obj['ttl']          = convert_time(ttl)
            obj['contact']      = contact
            obj['mx']           = mx
            diff = obj.diff()
            if exists:
                for k in obj.keys():
                    if obj.hasChanged(k):
                        changed = True
            else:
                changed = True
            if not module.check_mode:
                if not exists:
                    obj.create()
                elif changed:
                    obj.modify()
        except Exception as e:
            module.fail_json(
                msg='Creating/editing dns zone {} failed: {}'.format(zone, e)
            )

    if state == 'absent' and exists:
        try:
            obj = umc_module_for_edit('dns/{}'.format(type), dn)
            if not module.check_mode:
                obj.remove()
            changed = True
        except Exception as e:
            module.fail_json(
                msg='Removing dns zone {} failed: {}'.format(zone, e)
            )

    module.exit_json(
        changed=changed,
        diff=diff,
        zone=zone
    )


if __name__ == '__main__':
    main()