#
# 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_system
extends_documentation_fragment:
- cisco.nxos.nxos
author: Peter Sprygada (@privateip)
short_description: Manage the system attributes on Cisco NXOS devices
notes:
- Unsupported for Cisco MDS
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.
version_added: 1.0.0
options:
  hostname:
    description:
    - Configure the device hostname parameter. This option takes an ASCII string value
      or keyword 'default'
    type: str
  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 or keyword 'default'. See
      examples.
    type: list
    elements: raw
  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.
    type: bool
  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 or keyword 'default'. See
      examples.
    type: list
    elements: raw
  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 or keyword 'default'. See examples.
    type: list
    elements: raw
  system_mtu:
    description:
    - Specifies the mtu, must be an integer or keyword 'default'.
    type: 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
    choices:
    - present
    - absent
    type: str
"""

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

- name: remove configuration
  cisco.nxos.nxos_system:
    state: absent

- name: configure name servers
  cisco.nxos.nxos_system:
    name_servers:
    - 8.8.8.8
    - 8.8.4.4

- name: configure name servers with VRF support
  cisco.nxos.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.basic import AnsibleModule
from ansible.module_utils.six import iteritems
from ansible_collections.ansible.netcommon.plugins.module_utils.network.common.config import (
    NetworkConfig,
)
from ansible_collections.ansible.netcommon.plugins.module_utils.network.common.utils import (
    ComplexList,
)

from ansible_collections.cisco.nxos.plugins.module_utils.network.nxos.nxos 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 context (\S+)", config)
    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))

    def difference(x, y, z):
        return [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"):
            if want["hostname"] == "default":
                if have["hostname"]:
                    commands.append("no hostname")
            else:
                commands.append("hostname %s" % want["hostname"])

        if want.get("domain_lookup") is not None:
            if have.get("domain_lookup") != want.get("domain_lookup"):
                cmd = "ip domain-lookup"
                if want["domain_lookup"] is False:
                    cmd = "no %s" % cmd
                commands.append(cmd)

        if want["domain_name"]:
            if want.get("domain_name")[0]["name"] == "default":
                if have["domain_name"]:
                    for item in have["domain_name"]:
                        cmd = "no ip domain-name %s" % item["name"]
                        remove(cmd, commands, item["vrf"])
            else:
                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"]:
            if want.get("domain_search")[0]["name"] == "default":
                if have["domain_search"]:
                    for item in have["domain_search"]:
                        cmd = "no ip domain-list %s" % item["name"]
                        remove(cmd, commands, item["vrf"])
            else:
                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"]:
            if want.get("name_servers")[0]["server"] == "default":
                if have["name_servers"]:
                    for item in have["name_servers"]:
                        cmd = "no ip name-server %s" % item["server"]
                        remove(cmd, commands, item["vrf"])
            else:
                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"):
            if want["system_mtu"] == "default":
                if have["system_mtu"]:
                    commands.append("no system jumbomtu")
            else:
                commands.append("system jumbomtu %s" % want["system_mtu"])

    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, vrf_config):
    objects = list()
    match = re.search(r"^ip domain-name (\S+)", config, re.M)
    if match:
        objects.append({"name": match.group(1), "vrf": None})

    for vrf, cfg in iteritems(vrf_config):
        match = re.search(r"ip domain-name (\S+)", 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(r"^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(r"ip domain-list (\S+)", cfg, re.M):
            objects.append({"name": item, "vrf": vrf})

    return objects


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

    match = re.search("^ip name-server (.+)$", config, re.M)
    if match and "use-vrf" not in match.group(1):
        for addr in match.group(1).split(" "):
            objects.append({"server": addr, "vrf": None})

    for vrf, cfg in iteritems(vrf_config):
        vrf_match = re.search("ip name-server (.+)", cfg, re.M)
        if vrf_match:
            for addr in vrf_match.group(1).split(" "):
                objects.append({"server": addr, "vrf": vrf})

    return objects


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


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

    vrf_config = {}

    vrfs = re.findall(r"^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, vrfs),
        "system_mtu": parse_system_mtu(config),
    }


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", elements="raw"),
        # {name: <str>, vrf: <str> }
        domain_search=dict(type="list", elements="raw"),
        # { server: <str>; vrf: <str> }
        name_servers=dict(type="list", elements="raw"),
        system_mtu=dict(type="str"),
        state=dict(default="present", choices=["present", "absent"]),
    )

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

    warnings = list()

    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()