#!/usr/bin/python
#
# 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/>.
#

ANSIBLE_METADATA = {'metadata_version': '1.0',
                    'status': ['preview'],
                    'supported_by': 'core'}


DOCUMENTATION = """
---
module: nxos_system
extends_documentation_fragment: nxos
version_added: "2.3"
author: "Peter Sprygada (@privateip)"
short_description: Manage the system attributes on Cisco NXOS devices
description:
  - This module provides declarative management of node system attributes
    on Cisco NXOS devices.  It provides an option to configure host system
    parameters or remove those parameters from the device active
    configuration.
options:
  hostname:
    description:
      - Configure the device hostname parameter. This option takes an ASCII string value.
  domain_name:
    description:
      - Configures the default domain
        name suffix to be used when referencing this node by its
        FQDN.  This argument accepts either a list of domain names or
        a list of dicts that configure the domain name and VRF name.  See
        examples.
  domain_lookup:
    description:
      - Enables or disables the DNS
        lookup feature in Cisco NXOS.  This argument accepts boolean
        values.  When enabled, the system will try to resolve hostnames
        using DNS and when disabled, hostnames will not be resolved.
  domain_search:
    description:
      - Configures a list of domain
        name suffixes to search when performing DNS name resolution.
        This argument accepts either a list of domain names or
        a list of dicts that configure the domain name and VRF name.  See
        examples.
  name_servers:
    description:
      - List of DNS name servers by IP address to use to perform name resolution
        lookups.  This argument accepts either a list of DNS servers or
        a list of hashes that configure the name server and VRF name.  See
        examples.
  system_mtu:
    description:
      - Specifies the mtu, must be an integer.
  state:
    description:
      - State of the configuration
        values in the device's current active configuration.  When set
        to I(present), the values should be configured in the device active
        configuration and when set to I(absent) the values should not be
        in the device active configuration
    default: present
    choices: ['present', 'absent']
"""

EXAMPLES = """
- name: configure hostname and domain-name
  nxos_system:
    hostname: nxos01
    domain_name: test.example.com

- name: remove configuration
  nxos_system:
    state: absent

- name: configure DNS lookup sources
  nxos_system:
    lookup_source: Management1

- name: configure name servers
  nxos_system:
    name_servers:
      - 8.8.8.8
      - 8.8.4.4

- name: configure name servers with VRF support
  nxos_system:
    name_servers:
      - { server: 8.8.8.8, vrf: mgmt }
      - { server: 8.8.4.4, vrf: mgmt }
"""

RETURN = """
commands:
  description: The list of configuration mode commands to send to the device
  returned: always
  type: list
  sample:
    - hostname nxos01
    - ip domain-name test.example.com
"""
import re

from ansible.module_utils.nxos import get_config, load_config
from ansible.module_utils.nxos import nxos_argument_spec, check_args
from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.six import iteritems
from ansible.module_utils.netcfg import NetworkConfig
from ansible.module_utils.network_common import ComplexList

_CONFIGURED_VRFS = None

def has_vrf(module, vrf):
    global _CONFIGURED_VRFS
    if _CONFIGURED_VRFS is not None:
        return vrf in _CONFIGURED_VRFS
    config = get_config(module)
    _CONFIGURED_VRFS = re.findall('vrf context (\S+)', config)
    return vrf in _CONFIGURED_VRFS

def map_obj_to_commands(want, have, module):
    commands = list()
    state = module.params['state']

    needs_update = lambda x: want.get(x) and (want.get(x) != have.get(x))
    difference = lambda x,y,z: [item for item in x[z] if item not in y[z]]

    def remove(cmd, commands, vrf=None):
        if vrf:
            commands.append('vrf context %s' % vrf)
        commands.append(cmd)
        if vrf:
            commands.append('exit')

    def add(cmd, commands, vrf=None):
        if vrf:
            if not has_vrf(module, vrf):
                module.fail_json(msg='invalid vrf name %s' % vrf)
        return remove(cmd, commands, vrf)

    if state == 'absent':
        if have['hostname']:
            commands.append('no hostname')

        for item in have['domain_name']:
            cmd = 'no ip domain-name %s' % item['name']
            remove(cmd, commands, item['vrf'])

        for item in have['domain_search']:
            cmd = 'no ip domain-list %s' % item['name']
            remove(cmd, commands, item['vrf'])

        for item in have['name_servers']:
            cmd = 'no ip name-server %s' % item['server']
            remove(cmd, commands, item['vrf'])

        if have['system_mtu']:
            commands.append('no system jumbomtu')

    if state == 'present':
        if needs_update('hostname'):
            commands.append('hostname %s' % want['hostname'])

        if needs_update('domain_lookup'):
            cmd = 'ip domain-lookup'
            if want['domain_lookup'] is False:
                cmd = 'no %s' % cmd
            commands.append(cmd)

        if want['domain_name']:
            for item in difference(have, want, 'domain_name'):
                cmd = 'no ip domain-name %s' % item['name']
                remove(cmd, commands, item['vrf'])
            for item in difference(want, have, 'domain_name'):
                cmd = 'ip domain-name %s' % item['name']
                add(cmd, commands, item['vrf'])

        if want['domain_search']:
            for item in difference(have, want, 'domain_search'):
                cmd = 'no ip domain-list %s' % item['name']
                remove(cmd, commands, item['vrf'])
            for item in difference(want, have, 'domain_search'):
                cmd = 'ip domain-list %s' % item['name']
                add(cmd, commands, item['vrf'])

        if want['name_servers']:
            for item in difference(have, want, 'name_servers'):
                cmd = 'no ip name-server %s' %  item['server']
                remove(cmd, commands, item['vrf'])
            for item in difference(want, have, 'name_servers'):
                cmd = 'ip name-server %s' % item['server']
                add(cmd, commands, item['vrf'])

        if needs_update('system_mtu'):
            commands.append('system jumbomtu %s' % want['system_mtu'])

    return commands

def parse_hostname(config):
    match = re.search('^hostname (\S+)', config, re.M)
    if match:
        return match.group(1)

def parse_domain_name(config, vrf_config):
    objects = list()
    regex = re.compile('ip domain-name (\S+)')

    match = regex.search(config, re.M)
    if match:
        objects.append({'name': match.group(1), 'vrf': None})

    for vrf, cfg in iteritems(vrf_config):
        match = regex.search(cfg, re.M)
        if match:
            objects.append({'name': match.group(1), 'vrf': vrf})

    return objects

def parse_domain_search(config, vrf_config):
    objects = list()

    for item in re.findall('^ip domain-list (\S+)', config, re.M):
        objects.append({'name': item, 'vrf': None})

    for vrf, cfg in iteritems(vrf_config):
        for item in re.findall('ip domain-list (\S+)', cfg, re.M):
            objects.append({'name': item, 'vrf': vrf})

    return objects

def parse_name_servers(config, vrf_config):
    objects = list()

    match = re.search('^ip name-server (.+)$', config, re.M)
    if match:
        for addr in match.group(1).split(' '):
            objects.append({'server': addr, 'vrf': None})

    for vrf, cfg in iteritems(vrf_config):
        for item in re.findall('ip name-server (\S+)', cfg, re.M):
            for addr in match.group(1).split(' '):
                objects.append({'server': addr, 'vrf': vrf})

    return objects

def parse_system_mtu(config):
    match = re.search('^system jumbomtu (\d+)', config, re.M)
    if match:
        return int(match.group(1))

def map_config_to_obj(module):
    config = get_config(module)
    configobj = NetworkConfig(indent=2, contents=config)

    vrf_config = {}

    vrfs = re.findall('^vrf context (\S+)$', config, re.M)
    for vrf in vrfs:
        config_data = configobj.get_block_config(path=['vrf context %s' % vrf])
        vrf_config[vrf] = config_data

    return {
        'hostname': parse_hostname(config),
        'domain_lookup': 'no ip domain-lookup' not in config,
        'domain_name': parse_domain_name(config, vrf_config),
        'domain_search': parse_domain_search(config, vrf_config),
        'name_servers': parse_name_servers(config, vrf_config),
        'system_mtu': parse_system_mtu(config)
    }

def validate_system_mtu(value, module):
    if not 1500 <= value <= 9216:
        module.fail_json(msg='system_mtu must be between 1500 and 9216')

def map_params_to_obj(module):
    obj = {
        'hostname': module.params['hostname'],
        'domain_lookup': module.params['domain_lookup'],
        'system_mtu': module.params['system_mtu']
    }

    domain_name = ComplexList(dict(
        name=dict(key=True),
        vrf=dict()
    ), module)

    domain_search = ComplexList(dict(
        name=dict(key=True),
        vrf=dict()
    ), module)

    name_servers = ComplexList(dict(
        server=dict(key=True),
        vrf=dict()
    ), module)

    for arg, cast in [('domain_name', domain_name), ('domain_search', domain_search),
                      ('name_servers', name_servers)]:
        if module.params[arg] is not None:
            obj[arg] = cast(module.params[arg])
        else:
            obj[arg] = None

    return obj

def main():
    """ main entry point for module execution
    """
    argument_spec = dict(
        hostname=dict(),
        domain_lookup=dict(type='bool'),

        # { name: <str>, vrf: <str> }
        domain_name=dict(type='list'),

        # {name: <str>, vrf: <str> }
        domain_search=dict(type='list'),

        # { server: <str>; vrf: <str> }
        name_servers=dict(type='list'),

        system_mtu=dict(type='int'),

        state=dict(default='present', choices=['present', 'absent'])
    )

    argument_spec.update(nxos_argument_spec)

    module = AnsibleModule(argument_spec=argument_spec,
                           supports_check_mode=True)

    warnings = list()
    check_args(module, warnings)

    result = {'changed': False}
    if warnings:
        result['warnings'] = warnings

    want = map_params_to_obj(module)
    have = map_config_to_obj(module)

    commands = map_obj_to_commands(want, have, module)
    result['commands'] = commands

    if commands:
        if not module.check_mode:
            load_config(module, commands)
        result['changed'] = True

    module.exit_json(**result)

if __name__ == '__main__':
    main()
