#!/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/>.
#
from __future__ import absolute_import, division, print_function


__metaclass__ = type


DOCUMENTATION = """
module: nxos_overlay_global
extends_documentation_fragment:
- cisco.nxos.nxos
short_description: Configures anycast gateway MAC of the switch.
description:
- Configures anycast gateway MAC of the switch.
version_added: 1.0.0
author: Gabriele Gerbino (@GGabriele)
notes:
- Tested against NXOSv 7.3.(0)D1(1) on VIRL
- Unsupported for Cisco MDS
- 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
    type: str
"""

EXAMPLES = """
- cisco.nxos.nxos_overlay_global:
    anycast_gateway_mac: b.b.b
"""

RETURN = """
commands:
    description: commands sent to the device
    returned: always
    type: list
    sample: ["fabric forwarding anycast-gateway-mac 000B.000B.000B"]
"""

import re

from ansible.module_utils.basic import AnsibleModule
from ansible_collections.ansible.netcommon.plugins.module_utils.network.common.config import (
    CustomNetworkConfig,
)

from ansible_collections.cisco.nxos.plugins.module_utils.network.nxos.nxos import (
    get_config,
    load_config,
)


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


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

    for arg in args:
        command = PARAM_TO_COMMAND_KEYMAP[arg]
        has_command = re.findall(r"(?:{0}\s)(?P<value>.*)$".format(command), config, re.M)
        value = ""
        if has_command:
            value = has_command[0]
        existing[arg] = value

    return existing


def apply_key_map(key_map, table):
    new_dict = {}
    for key, value in table.items():
        new_key = key_map.get(key)
        if value:
            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, proposed in proposed_commands.items():
        existing_value = existing_commands.get(key)
        if proposed == "default" and existing_value:
            commands.append("no {0} {1}".format(key, existing_value))
        elif "anycast-gateway-mac" in key and proposed != "default":
            proposed = normalize_mac(proposed, module)
            existing_value = normalize_mac(existing_value, module)
            if proposed != existing_value:
                command = "{0} {1}".format(key, proposed)
                commands.append(command)
    if commands:
        candidate.add(commands, parents=[])


def normalize_mac(proposed_mac, module):
    if proposed_mac is None:
        return ""
    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)
    # fmt: off
    mac = [joined_mac[i: i + 4] for i in range(0, len(joined_mac), 4)]
    # fmt: on
    return ".".join(mac).upper()


def main():
    argument_spec = dict(anycast_gateway_mac=dict(required=True, type="str"))

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

    warnings = list()
    result = {"changed": False, "commands": [], "warnings": warnings}

    args = PARAM_TO_COMMAND_KEYMAP.keys()

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

    candidate = CustomNetworkConfig(indent=3)
    get_commands(module, existing, proposed, candidate)

    if candidate:
        candidate = candidate.items_text()
        result["commands"] = candidate

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

    module.exit_json(**result)


if __name__ == "__main__":
    main()