#!/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: eos_system
author: Peter Sprygada (@privateip)
short_description: Manage the system attributes on Arista EOS devices
description:
- This module provides declarative management of node system attributes on Arista
  EOS devices.  It provides an option to configure host system parameters or remove
  those parameters from the device active configuration.
version_added: 1.0.0
notes:
- Tested against Arista EOS 4.24.6F
options:
  hostname:
    description:
    - Configure the device hostname parameter. This option takes an ASCII string value.
    type: str
  domain_name:
    description:
    - Configure the IP domain name on the remote device to the provided value. Value
      should be in the dotted name form and will be appended to the C(hostname) to
      create a fully-qualified domain name.
    type: str
  domain_list:
    description:
    - Provides the list of domain suffixes to append to the hostname for the purpose
      of doing name resolution. This argument accepts a list of names and will be
      reconciled with the current active configuration on the running node.
    aliases:
    - domain_search
    type: list
    elements: str
  lookup_source:
    description:
    - Provides one or more source interfaces to use for performing DNS lookups.  The
      interface provided in C(lookup_source) can only exist in a single VRF.  This
      argument accepts either a list of interface names or a list of hashes that configure
      the interface name and VRF name.  See examples.
    elements: raw
    type: list
  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.
    type: list
    elements: str
  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
    type: str
    choices:
    - present
    - absent
"""

EXAMPLES = """
- name: configure hostname and domain-name
  arista.eos.eos_system:
    hostname: eos01
    domain_name: test.example.com

- name: remove configuration
  arista.eos.eos_system:
    state: absent

- name: configure DNS lookup sources
  arista.eos.eos_system:
    lookup_source: Management1

- name: configure DNS lookup sources with VRF support
  arista.eos.eos_system:
    lookup_source:
      - interface: Management1
        vrf: mgmt
      - interface: Ethernet1
        vrf: myvrf

- name: configure name servers
  arista.eos.eos_system:
    name_servers:
      - 8.8.8.8
      - 8.8.4.4

- name: configure name servers with VRF support
  arista.eos.eos_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 eos01
    - dns domain test.example.com
session_name:
  description: The EOS config session name used to load the configuration
  returned: changed
  type: str
  sample: ansible_1479315771
"""
import re

from ansible.module_utils.basic import AnsibleModule
from ansible_collections.ansible.netcommon.plugins.module_utils.network.common.utils import (
    ComplexList,
)

from ansible_collections.arista.eos.plugins.module_utils.network.eos.eos import (
    get_config,
    load_config,
)


_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(r"vrf instance (\S+)", config)
    _CONFIGURED_VRFS.append("default")
    return vrf in _CONFIGURED_VRFS


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

    def needs_update(x):
        return want.get(x) and (want.get(x) != have.get(x))

    if state == "absent":
        if have["domain_name"]:
            commands.append("no dns domain")

        if have["hostname"] != "localhost":
            commands.append("no hostname")

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

        if needs_update("domain_name"):
            commands.append("dns domain %s" % want["domain_name"])

        if want["domain_list"]:
            # handle domain_list items to be removed
            for item in set(have["domain_list"]).difference(
                want["domain_list"],
            ):
                commands.append("no ip domain-list %s" % item)

            # handle domain_list items to be added
            for item in set(want["domain_list"]).difference(
                have["domain_list"],
            ):
                commands.append("ip domain-list %s" % item)

        if want["lookup_source"]:
            # handle lookup_source items to be removed
            for item in have["lookup_source"]:
                if item not in want["lookup_source"]:
                    if item["vrf"]:
                        if not has_vrf(module, item["vrf"]):
                            module.fail_json(
                                msg="vrf %s is not configured" % item["vrf"],
                            )
                        values = (item["vrf"], item["interface"])
                        commands.append(
                            "no ip domain lookup vrf %s source-interface %s" % values,
                        )
                    else:
                        commands.append(
                            "no ip domain lookup source-interface %s" % item["interface"],
                        )

            # handle lookup_source items to be added
            for item in want["lookup_source"]:
                if item not in have["lookup_source"]:
                    if item["vrf"]:
                        if not has_vrf(module, item["vrf"]):
                            module.fail_json(
                                msg="vrf %s is not configured" % item["vrf"],
                            )
                        values = (item["vrf"], item["interface"])
                        commands.append(
                            "ip domain lookup vrf %s source-interface %s" % values,
                        )
                    else:
                        commands.append(
                            "ip domain lookup source-interface %s" % item["interface"],
                        )

        if want["name_servers"]:
            # handle name_servers items to be removed.  Order does matter here
            # since name servers can only be in one vrf at a time
            for item in have["name_servers"]:
                if item not in want["name_servers"]:
                    if not has_vrf(module, item["vrf"]):
                        module.fail_json(
                            msg="vrf %s is not configured" % item["vrf"],
                        )
                    if item["vrf"] not in ("default", None):
                        values = (item["vrf"], item["server"])
                        commands.append("no ip name-server vrf %s %s" % values)
                    else:
                        commands.append(
                            "no ip name-server %s" % item["server"],
                        )

            # handle name_servers items to be added
            for item in want["name_servers"]:
                if item not in have["name_servers"]:
                    if not has_vrf(module, item["vrf"]):
                        module.fail_json(
                            msg="vrf %s is not configured" % item["vrf"],
                        )
                    if item["vrf"] not in ("default", None):
                        values = (item["vrf"], item["server"])
                        commands.append("ip name-server vrf %s %s" % values)
                    else:
                        commands.append("ip name-server %s" % item["server"])

    return commands


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


def parse_domain_name(config):
    match = re.search(r"^dns domain (\S+)", config, re.M)
    if match:
        return match.group(1)


def parse_lookup_source(config):
    objects = list()
    regex = r"ip domain lookup (?:vrf (\S+) )*source-interface (\S+)"
    for vrf, intf in re.findall(regex, config, re.M):
        if len(vrf) == 0:
            vrf = None
        objects.append({"interface": intf, "vrf": vrf})
    return objects


def parse_name_servers(config):
    objects = list()
    for vrf, addr in re.findall(
        r"ip name-server vrf (\S+) (\S+)",
        config,
        re.M,
    ):
        objects.append({"server": addr, "vrf": vrf})
    return objects


def map_config_to_obj(module):
    config = get_config(module)
    return {
        "hostname": parse_hostname(config),
        "domain_name": parse_domain_name(config),
        "domain_list": re.findall(r"^ip domain-list (\S+)", config, re.M),
        "lookup_source": parse_lookup_source(config),
        "name_servers": parse_name_servers(config),
    }


def map_params_to_obj(module):
    obj = {
        "hostname": module.params["hostname"],
        "domain_name": module.params["domain_name"],
        "domain_list": module.params["domain_list"],
    }

    lookup_source = ComplexList(
        dict(interface=dict(key=True), vrf=dict()),
        module,
    )

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

    for arg, cast in [
        ("lookup_source", lookup_source),
        ("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_name=dict(),
        domain_list=dict(
            type="list",
            aliases=["domain_search"],
            elements="str",
        ),
        # { interface: <str>, vrf: <str> }
        lookup_source=dict(type="list", elements="raw"),
        # { server: <str>; vrf: <str> }
        name_servers=dict(type="list", elements="str"),
        state=dict(default="present", choices=["present", "absent"]),
    )

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

    result = {"changed": False}

    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:
        commit = not module.check_mode
        response = load_config(module, commands, commit=commit)
        if response.get("diff") and module._diff:
            result["diff"] = {"prepared": response.get("diff")}
        result["session_name"] = response.get("session")
        result["changed"] = True

    module.exit_json(**result)


if __name__ == "__main__":
    main()