#!/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 = {'status': ['preview'],
                    'supported_by': 'community',
                    'version': '1.0'}

DOCUMENTATION = '''
---
module: nxos_overlay_global
extends_documentation_fragment: nxos
version_added: "2.2"
short_description: Configures anycast gateway MAC of the switch.
description:
    - Configures anycast gateway MAC of the switch.
author: Gabriele Gerbino (@GGabriele)
notes:
    - Default restores params default value
    - Supported MAC address format are "E.E.E", "EE-EE-EE-EE-EE-EE",
      "EE:EE:EE:EE:EE:EE" and "EEEE.EEEE.EEEE"
options:
    anycast_gateway_mac:
        description:
            - Anycast gateway mac of the switch.
        required: true
        default: null
'''

EXAMPLES = '''
- nxos_overlay_global:
    anycast_gateway_mac: "b.b.b"
    username: "{{ un }}"
    password: "{{ pwd }}"
    host: "{{ inventory_hostname }}"
'''

RETURN = '''
proposed:
    description: k/v pairs of parameters passed into module
    returned: verbose mode
    type: dict
    sample: {"asn": "65535", "router_id": "1.1.1.1", "vrf": "test"}
existing:
    description: k/v pairs of existing BGP configuration
    returned: verbose mode
    type: dict
    sample: {"asn": "65535", "bestpath_always_compare_med": false,
            "bestpath_aspath_multipath_relax": false,
            "bestpath_compare_neighborid": false,
            "bestpath_compare_routerid": false,
            "bestpath_cost_community_ignore": false,
            "bestpath_med_confed": false,
            "bestpath_med_missing_as_worst": false,
            "bestpath_med_non_deterministic": false, "cluster_id": "",
            "confederation_id": "", "confederation_peers": "",
            "graceful_restart": true, "graceful_restart_helper": false,
            "graceful_restart_timers_restart": "120",
            "graceful_restart_timers_stalepath_time": "300", "local_as": "",
            "log_neighbor_changes": false, "maxas_limit": "",
            "neighbor_down_fib_accelerate": false, "reconnect_interval": "60",
            "router_id": "11.11.11.11", "suppress_fib_pending": false,
            "timer_bestpath_limit": "", "timer_bgp_hold": "180",
            "timer_bgp_keepalive": "60", "vrf": "test"}
end_state:
    description: k/v pairs of BGP configuration after module execution
    returned: verbose mode
    type: dict
    sample: {"asn": "65535", "bestpath_always_compare_med": false,
            "bestpath_aspath_multipath_relax": false,
            "bestpath_compare_neighborid": false,
            "bestpath_compare_routerid": false,
            "bestpath_cost_community_ignore": false,
            "bestpath_med_confed": false,
            "bestpath_med_missing_as_worst": false,
            "bestpath_med_non_deterministic": false, "cluster_id": "",
            "confederation_id": "", "confederation_peers": "",
            "graceful_restart": true, "graceful_restart_helper": false,
            "graceful_restart_timers_restart": "120",
            "graceful_restart_timers_stalepath_time": "300", "local_as": "",
            "log_neighbor_changes": false, "maxas_limit": "",
            "neighbor_down_fib_accelerate": false, "reconnect_interval": "60",
            "router_id": "1.1.1.1",  "suppress_fib_pending": false,
            "timer_bestpath_limit": "", "timer_bgp_hold": "180",
            "timer_bgp_keepalive": "60", "vrf": "test"}
updates:
    description: commands sent to the device
    returned: always
    type: list
    sample: ["router bgp 65535", "vrf test", "router-id 1.1.1.1"]
changed:
    description: check to see if a change was made on the device
    returned: always
    type: boolean
    sample: true
'''

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.netcfg import CustomNetworkConfig

PARAM_TO_COMMAND_KEYMAP = {
    'anycast_gateway_mac': 'fabric forwarding anycast-gateway-mac',
}


def invoke(name, *args, **kwargs):
    func = globals().get(name)
    if func:
        return func(*args, **kwargs)


def get_value(arg, config, module):
    REGEX = re.compile(r'(?:{0}\s)(?P<value>.*)$'.format(PARAM_TO_COMMAND_KEYMAP[arg]), re.M)
    value = ''
    if PARAM_TO_COMMAND_KEYMAP[arg] in config:
        value = REGEX.search(config).group('value')
    return value


def get_existing(module, args):
    existing = {}
    config = str(get_config(module))

    for arg in args:
        existing[arg] = get_value(arg, config, module)
    return existing


def apply_key_map(key_map, table):
    new_dict = {}
    for key, value in table.items():
        new_key = key_map.get(key)
        if new_key:
            value = table.get(key)
            if value:
                new_dict[new_key] = value
            else:
                new_dict[new_key] = value
    return new_dict


def get_commands(module, existing, proposed, candidate):
    commands = list()
    proposed_commands = apply_key_map(PARAM_TO_COMMAND_KEYMAP, proposed)
    existing_commands = apply_key_map(PARAM_TO_COMMAND_KEYMAP, existing)

    for key, value in proposed_commands.items():
        if value == 'default':
            existing_value = existing_commands.get(key)
            if existing_value:
                commands.append('no {0} {1}'.format(key, existing_value))
        else:
            if 'anycast-gateway-mac' in key:
                value = normalize_mac(value, module)
            command = '{0} {1}'.format(key, value)
            commands.append(command)

    if commands:
        candidate.add(commands, parents=[])


def normalize_mac(proposed_mac, module):
    try:
        if '-' in proposed_mac:
            splitted_mac = proposed_mac.split('-')
            if len(splitted_mac) != 6:
                raise ValueError

            for octect in splitted_mac:
                if len(octect) != 2:
                    raise ValueError

        elif '.' in proposed_mac:
            splitted_mac = []
            splitted_dot_mac = proposed_mac.split('.')
            if len(splitted_dot_mac) != 3:
                raise ValueError

            for octect in splitted_dot_mac:
                if len(octect) > 4:
                    raise ValueError
                else:
                    octect_len = len(octect)
                    padding = 4 - octect_len
                    splitted_mac.append(octect.zfill(padding+1))

        elif ':' in proposed_mac:
            splitted_mac = proposed_mac.split(':')
            if len(splitted_mac) != 6:
                raise ValueError

            for octect in splitted_mac:
                if len(octect) != 2:
                    raise ValueError
        else:
            raise ValueError
    except ValueError:
        module.fail_json(msg='Invalid MAC address format',
                             proposed_mac=proposed_mac)

    joined_mac = ''.join(splitted_mac)
    mac = [joined_mac[i:i+4] for i in range(0, len(joined_mac), 4)]
    return '.'.join(mac).upper()


def main():
    argument_spec = dict(
        anycast_gateway_mac=dict(required=True, type='str'),
        m_facts=dict(required=False, default=False, type='bool'),
    )

    argument_spec.update(nxos_argument_spec)

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

    warnings = list()
    check_args(module, warnings)

    args =  [
        'anycast_gateway_mac'
    ]

    existing = invoke('get_existing', module, args)
    end_state = existing
    proposed = dict((k, v) for k, v in module.params.items()
                    if v is not None and k in args)

    result = {}
    candidate = CustomNetworkConfig(indent=3)
    invoke('get_commands', module, existing, proposed, candidate)

    if not module.check_mode:
        load_config(module, candidate)

    if module._verbosity > 0:
        end_state = invoke('get_existing', module, args)
        result['end_state'] = end_state
        result['existing'] = existing
        result['proposed'] = proposed

    result['warnings'] = True

    module.exit_json(**result)


if __name__ == '__main__':
    main()

