#!/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_snmp_host
extends_documentation_fragment:
- cisco.nxos.nxos
short_description: Manages SNMP host configuration.
description:
- Manages SNMP host configuration parameters.
version_added: 1.0.0
author:
- Jason Edelman (@jedelman8)
- Gabriele Gerbino (@GGabriele)
notes:
- Tested against NXOSv 7.3.(0)D1(1) on VIRL
- C(state=absent) removes the host configuration if it is configured.
options:
  snmp_host:
    description:
    - IP address of hostname of target host.
    required: true
    type: str
  version:
    description:
    - SNMP version. If this is not specified, v1 is used.
    choices:
    - v1
    - v2c
    - v3
    type: str
  v3:
    description:
    - Use this when verion is v3. SNMPv3 Security level.
    choices:
    - noauth
    - auth
    - priv
    type: str
  community:
    description:
    - Community string or v3 username.
    type: str
  udp:
    description:
    - UDP port number (0-65535).
    default: 162
    type: str
  snmp_type:
    description:
    - type of message to send to host. If this is not specified, trap type is used.
    choices:
    - trap
    - inform
    type: str
  vrf:
    description:
    - VRF to use to source traffic to source. If state = absent, the vrf is removed.
    type: str
  vrf_filter:
    description:
    - Name of VRF to filter. If state = absent, the vrf is removed from the filter.
    type: str
  src_intf:
    description:
    - Source interface. Must be fully qualified interface name. If state = absent,
      the interface is removed.
    type: str
  state:
    description:
    - Manage the state of the resource. If state = present, the host is added to the
      configuration. If only vrf and/or vrf_filter and/or src_intf are given, they
      will be added to the existing host configuration. If state = absent, the host
      is removed if community parameter is given. It is possible to remove only vrf
      and/or src_int and/or vrf_filter by providing only those parameters and no community
      parameter.
    default: present
    choices:
    - present
    - absent
    type: str
"""

EXAMPLES = """
# ensure snmp host is configured
- cisco.nxos.nxos_snmp_host:
    snmp_host: 192.0.2.3
    community: TESTING
    state: present
"""

RETURN = """
commands:
    description: commands sent to the device
    returned: always
    type: list
    sample: ["snmp-server host 192.0.2.3 filter-vrf another_test_vrf"]
"""


import re
from ansible_collections.cisco.nxos.plugins.module_utils.network.nxos.nxos import (
    load_config,
    run_commands,
)
from ansible_collections.cisco.nxos.plugins.module_utils.network.nxos.nxos import (
    nxos_argument_spec,
)
from ansible.module_utils.basic import AnsibleModule


def execute_show_command(command, module):
    command = {"command": command, "output": "json"}

    return run_commands(module, command)


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] = str(value)
            else:
                new_dict[new_key] = value
    return new_dict


def flatten_list(command_lists):
    flat_command_list = []
    for command in command_lists:
        if isinstance(command, list):
            flat_command_list.extend(command)
        else:
            flat_command_list.append(command)
    return flat_command_list


def get_snmp_host(host, udp, module):
    body = execute_show_command("show snmp host", module)

    host_map = {
        "port": "udp",
        "version": "version",
        "level": "v3",
        "type": "snmp_type",
        "secname": "community",
    }

    host_map_5k = {
        "port": "udp",
        "version": "version",
        "sec_level": "v3",
        "notif_type": "snmp_type",
        "commun_or_user": "community",
    }

    resource = {}

    if body:
        try:
            resource_table = body[0]["TABLE_host"]["ROW_host"]

            if isinstance(resource_table, dict):
                resource_table = [resource_table]

            for each in resource_table:
                key = str(each["host"]) + "_" + str(each["port"]).strip()
                src = each.get("src_intf")
                host_resource = apply_key_map(host_map, each)

                if src:
                    host_resource["src_intf"] = src
                    if re.search(r"interface:", src):
                        host_resource["src_intf"] = src.split(":")[1].strip()

                vrf_filt = each.get("TABLE_vrf_filters")
                if vrf_filt:
                    vrf_filter = (
                        vrf_filt["ROW_vrf_filters"]["vrf_filter"]
                        .split(":")[1]
                        .split(",")
                    )
                    filters = [vrf.strip() for vrf in vrf_filter]
                    host_resource["vrf_filter"] = filters

                vrf = each.get("vrf")
                if vrf:
                    host_resource["vrf"] = vrf.split(":")[1].strip()
                resource[key] = host_resource
        except KeyError:
            # Handle the 5K case
            try:
                resource_table = body[0]["TABLE_hosts"]["ROW_hosts"]

                if isinstance(resource_table, dict):
                    resource_table = [resource_table]

                for each in resource_table:
                    key = (
                        str(each["address"]) + "_" + str(each["port"]).strip()
                    )
                    src = each.get("src_intf")
                    host_resource = apply_key_map(host_map_5k, each)

                    if src:
                        host_resource["src_intf"] = src
                        if re.search(r"interface:", src):
                            host_resource["src_intf"] = src.split(":")[
                                1
                            ].strip()

                    vrf = each.get("use_vrf_name")
                    if vrf:
                        host_resource["vrf"] = vrf.strip()

                    vrf_filt = each.get("TABLE_filter_vrf")
                    if vrf_filt:
                        vrf_filter = vrf_filt["ROW_filter_vrf"][
                            "filter_vrf_name"
                        ].split(",")
                        filters = [vrf.strip() for vrf in vrf_filter]
                        host_resource["vrf_filter"] = filters

                    resource[key] = host_resource
            except (KeyError, AttributeError, TypeError):
                return resource
        except (AttributeError, TypeError):
            return resource

        find = resource.get(host + "_" + udp)

        if find:
            fix_find = {}
            for (key, value) in find.items():
                if isinstance(value, str):
                    fix_find[key] = value.strip()
                else:
                    fix_find[key] = value
            return fix_find

    return {}


def remove_snmp_host(host, udp, existing):
    commands = []
    if existing["version"] == "v3":
        existing["version"] = "3"
        command = "no snmp-server host {0} {snmp_type} version \
                    {version} {v3} {community} udp-port {1}".format(
            host, udp, **existing
        )

    elif existing["version"] == "v2c":
        existing["version"] = "2c"
        command = "no snmp-server host {0} {snmp_type} version \
                    {version} {community} udp-port {1}".format(
            host, udp, **existing
        )

    elif existing["version"] == "v1":
        existing["version"] = "1"
        command = "no snmp-server host {0} {snmp_type} version \
                    {version} {community} udp-port {1}".format(
            host, udp, **existing
        )

    if command:
        commands.append(command)
    return commands


def remove_vrf(host, udp, proposed, existing):
    commands = []
    if existing.get("vrf"):
        commands.append(
            "no snmp-server host {0} use-vrf \
                    {1} udp-port {2}".format(
                host, proposed.get("vrf"), udp
            )
        )
    return commands


def remove_filter(host, udp, proposed, existing):
    commands = []
    if existing.get("vrf_filter"):
        if proposed.get("vrf_filter") in existing.get("vrf_filter"):
            commands.append(
                "no snmp-server host {0} filter-vrf \
                    {1} udp-port {2}".format(
                    host, proposed.get("vrf_filter"), udp
                )
            )
    return commands


def remove_src(host, udp, proposed, existing):
    commands = []
    if existing.get("src_intf"):
        commands.append(
            "no snmp-server host {0} source-interface \
                    {1} udp-port {2}".format(
                host, proposed.get("src_intf"), udp
            )
        )
    return commands


def config_snmp_host(delta, udp, proposed, existing, module):
    commands = []
    command_builder = []
    host = proposed["snmp_host"]
    cmd = "snmp-server host {0}".format(proposed["snmp_host"])

    snmp_type = delta.get("snmp_type")
    version = delta.get("version")
    ver = delta.get("v3")
    community = delta.get("community")

    command_builder.append(cmd)
    if any([snmp_type, version, ver, community]):
        type_string = snmp_type or existing.get("type")
        if type_string:
            command_builder.append(type_string)

        version = version or existing.get("version")
        if version:
            if version == "v1":
                vn = "1"
            elif version == "v2c":
                vn = "2c"
            elif version == "v3":
                vn = "3"

            version_string = "version {0}".format(vn)
            command_builder.append(version_string)

        if ver:
            ver_string = ver or existing.get("v3")
            command_builder.append(ver_string)

        if community:
            community_string = community or existing.get("community")
            command_builder.append(community_string)

        udp_string = " udp-port {0}".format(udp)
        command_builder.append(udp_string)

        cmd = " ".join(command_builder)

        commands.append(cmd)

    CMDS = {
        "vrf_filter": "snmp-server host {0} filter-vrf {vrf_filter} udp-port {1}",
        "vrf": "snmp-server host {0} use-vrf {vrf} udp-port {1}",
        "src_intf": "snmp-server host {0} source-interface {src_intf} udp-port {1}",
    }

    for key in delta:
        command = CMDS.get(key)
        if command:
            cmd = command.format(host, udp, **delta)
            commands.append(cmd)
    return commands


def main():
    argument_spec = dict(
        snmp_host=dict(required=True, type="str"),
        community=dict(type="str"),
        udp=dict(type="str", default="162"),
        version=dict(choices=["v1", "v2c", "v3"]),
        src_intf=dict(type="str"),
        v3=dict(choices=["noauth", "auth", "priv"]),
        vrf_filter=dict(type="str"),
        vrf=dict(type="str"),
        snmp_type=dict(choices=["trap", "inform"]),
        state=dict(choices=["absent", "present"], default="present"),
    )

    argument_spec.update(nxos_argument_spec)

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

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

    snmp_host = module.params["snmp_host"]
    community = module.params["community"]
    udp = module.params["udp"]
    version = module.params["version"]
    src_intf = module.params["src_intf"]
    v3 = module.params["v3"]
    vrf_filter = module.params["vrf_filter"]
    vrf = module.params["vrf"]
    snmp_type = module.params["snmp_type"]
    state = module.params["state"]

    existing = get_snmp_host(snmp_host, udp, module)

    if version is None:
        if existing:
            version = existing.get("version")
        else:
            version = "v1"

    if snmp_type is None:
        if existing:
            snmp_type = existing.get("snmp_type")
        else:
            snmp_type = "trap"

    if v3 is None:
        if version == "v3" and existing:
            v3 = existing.get("v3")

    if snmp_type == "inform" and version == "v1":
        module.fail_json(msg="inform requires snmp v2c or v3")

    if (version == "v1" or version == "v2c") and v3:
        module.fail_json(
            msg='param: "v3" should not be used when '
            "using version v1 or v2c"
        )

    if not any([vrf_filter, vrf, src_intf]):
        if not all([snmp_type, version, community, udp]):
            module.fail_json(
                msg="when not configuring options like "
                "vrf_filter, vrf, and src_intf,"
                "the following params are required: "
                "type, version, community"
            )

    if version == "v3" and v3 is None:
        module.fail_json(
            msg="when using version=v3, the param v3 "
            "(options: auth, noauth, priv) is also required"
        )

    # existing returns the list of vrfs configured for a given host
    # checking to see if the proposed is in the list
    store = existing.get("vrf_filter")
    if existing and store:
        if vrf_filter not in existing["vrf_filter"]:
            existing["vrf_filter"] = None
        else:
            existing["vrf_filter"] = vrf_filter
    commands = []

    args = dict(
        community=community,
        snmp_host=snmp_host,
        udp=udp,
        version=version,
        src_intf=src_intf,
        vrf_filter=vrf_filter,
        v3=v3,
        vrf=vrf,
        snmp_type=snmp_type,
    )
    proposed = dict((k, v) for k, v in args.items() if v is not None)

    if state == "absent" and existing:
        if proposed.get("community"):
            commands.append(remove_snmp_host(snmp_host, udp, existing))
        else:
            if proposed.get("src_intf"):
                commands.append(remove_src(snmp_host, udp, proposed, existing))
            if proposed.get("vrf"):
                commands.append(remove_vrf(snmp_host, udp, proposed, existing))
            if proposed.get("vrf_filter"):
                commands.append(
                    remove_filter(snmp_host, udp, proposed, existing)
                )

    elif state == "present":
        delta = dict(set(proposed.items()).difference(existing.items()))
        if delta:
            command = config_snmp_host(delta, udp, proposed, existing, module)
            commands.append(command)

    cmds = flatten_list(commands)
    if cmds:
        results["changed"] = True
        if not module.check_mode:
            load_config(module, cmds)

        if "configure" in cmds:
            cmds.pop(0)
        results["commands"] = cmds

    module.exit_json(**results)


if __name__ == "__main__":
    main()
