#!/usr/bin/python

# Copyright (c) 2016, Loic Blot <loic.blot@unix-experience.fr>
# Sponsored by Infopro Digital. http://www.infopro-digital.com/
# Sponsored by E.T.A.I. http://www.etai.fr/
# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
# SPDX-License-Identifier: GPL-3.0-or-later

from __future__ import annotations

DOCUMENTATION = r"""
module: omapi_host
short_description: Setup OMAPI hosts
description: Manage OMAPI hosts into compatible DHCPd servers.
requirements:
  - pypureomapi
author:
  - Loic Blot (@nerzhul)
extends_documentation_fragment:
  - community.general.attributes
attributes:
  check_mode:
    support: none
  diff_mode:
    support: none
options:
  state:
    description:
      - Create or remove OMAPI host.
    type: str
    required: true
    choices: [absent, present]
  hostname:
    description:
      - Sets the host lease hostname (mandatory if O(state=present)).
    type: str
    aliases: [name]
  host:
    description:
      - Sets OMAPI server host to interact with.
    type: str
    default: localhost
  port:
    description:
      - Sets the OMAPI server port to interact with.
    type: int
    default: 7911
  key_name:
    description:
      - Sets the TSIG key name for authenticating against OMAPI server.
    type: str
    required: true
  key:
    description:
      - Sets the TSIG key content for authenticating against OMAPI server.
    type: str
    required: true
  macaddr:
    description:
      - Sets the lease host MAC address.
    type: str
    required: true
  ip:
    description:
      - Sets the lease host IP address.
    type: str
  statements:
    description:
      - Attach a list of OMAPI DHCP statements with host lease (without ending semicolon).
    type: list
    elements: str
    default: []
  ddns:
    description:
      - Enable dynamic DNS updates for this host.
    type: bool
    default: false
"""
EXAMPLES = r"""
- name: Add a host using OMAPI
  community.general.omapi_host:
    key_name: defomapi
    key: +bFQtBCta6j2vWkjPkNFtgA==
    host: 10.98.4.55
    macaddr: 44:dd:ab:dd:11:44
    name: server01
    ip: 192.168.88.99
    ddns: true
    statements:
      - filename "pxelinux.0"
      - next-server 1.1.1.1
    state: present

- name: Remove a host using OMAPI
  community.general.omapi_host:
    key_name: defomapi
    key: +bFQtBCta6j2vWkjPkNFtgA==
    host: 10.1.1.1
    macaddr: 00:66:ab:dd:11:44
    state: absent
"""

RETURN = r"""
lease:
  description: Dictionary containing host information.
  returned: success
  type: complex
  contains:
    ip-address:
      description: IP address, if there is.
      returned: success
      type: str
      sample: '192.168.1.5'
    hardware-address:
      description: MAC address.
      returned: success
      type: str
      sample: '00:11:22:33:44:55'
    hardware-type:
      description: Hardware type, generally V(1).
      returned: success
      type: int
      sample: 1
    name:
      description: Hostname.
      returned: success
      type: str
      sample: 'mydesktop'
"""

import binascii
import socket
import struct
import traceback

PUREOMAPI_IMP_ERR = None
try:
    from pypureomapi import Omapi, OmapiMessage, OmapiError, OmapiErrorNotFound
    from pypureomapi import pack_ip, unpack_ip, pack_mac, unpack_mac
    from pypureomapi import OMAPI_OP_STATUS, OMAPI_OP_UPDATE

    pureomapi_found = True
except ImportError:
    PUREOMAPI_IMP_ERR = traceback.format_exc()
    pureomapi_found = False

from ansible.module_utils.basic import AnsibleModule, missing_required_lib
from ansible.module_utils.common.text.converters import to_bytes, to_native, to_text


class OmapiHostManager:
    def __init__(self, module):
        self.module = module
        self.omapi = None
        self.connect()

    def connect(self):
        try:
            self.omapi = Omapi(
                self.module.params["host"],
                self.module.params["port"],
                to_bytes(self.module.params["key_name"]),
                self.module.params["key"],
            )
        except binascii.Error:
            self.module.fail_json(msg="Unable to open OMAPI connection. 'key' is not a valid base64 key.")
        except OmapiError as e:
            self.module.fail_json(
                msg=f"Unable to open OMAPI connection. Ensure 'host', 'port', 'key' and 'key_name' are valid. Exception was: {e}"
            )
        except socket.error as e:
            self.module.fail_json(msg=f"Unable to connect to OMAPI server: {e}")

    def get_host(self, macaddr):
        msg = OmapiMessage.open(to_bytes("host", errors="surrogate_or_strict"))
        msg.obj.append((to_bytes("hardware-address", errors="surrogate_or_strict"), pack_mac(macaddr)))
        msg.obj.append((to_bytes("hardware-type", errors="surrogate_or_strict"), struct.pack("!I", 1)))
        response = self.omapi.query_server(msg)
        if response.opcode != OMAPI_OP_UPDATE:
            return None
        return response

    @staticmethod
    def unpack_facts(obj):
        result = {}
        for k, v in dict(obj).items():
            result[to_text(k)] = v

        if "hardware-address" in result:
            result["hardware-address"] = to_native(unpack_mac(result["hardware-address"]))

        if "ip-address" in result:
            result["ip-address"] = to_native(unpack_ip(result["ip-address"]))

        if "hardware-type" in result:
            result["hardware-type"] = struct.unpack("!I", result["hardware-type"])

        return result

    def setup_host(self):
        if self.module.params["hostname"] is None or len(self.module.params["hostname"]) == 0:
            self.module.fail_json(msg="name attribute could not be empty when adding or modifying host.")

        msg = None
        host_response = self.get_host(self.module.params["macaddr"])
        # If host was not found using macaddr, add create message
        if host_response is None:
            msg = OmapiMessage.open(to_bytes("host", errors="surrogate_or_strict"))
            msg.message.append((to_bytes("create"), struct.pack("!I", 1)))
            msg.message.append((to_bytes("exclusive"), struct.pack("!I", 1)))
            msg.obj.append((to_bytes("hardware-address"), pack_mac(self.module.params["macaddr"])))
            msg.obj.append((to_bytes("hardware-type"), struct.pack("!I", 1)))
            msg.obj.append((to_bytes("name"), to_bytes(self.module.params["hostname"])))
            if self.module.params["ip"] is not None:
                msg.obj.append(
                    (to_bytes("ip-address", errors="surrogate_or_strict"), pack_ip(self.module.params["ip"]))
                )

            stmt_join = ""
            if self.module.params["ddns"]:
                stmt_join += f'ddns-hostname "{self.module.params["hostname"]}"; '

            try:
                if len(self.module.params["statements"]) > 0:
                    stmt_join += "; ".join(self.module.params["statements"])
                    stmt_join += "; "
            except TypeError as e:
                self.module.fail_json(msg=f"Invalid statements found: {e}")

            if len(stmt_join) > 0:
                msg.obj.append((to_bytes("statements"), to_bytes(stmt_join)))

            try:
                response = self.omapi.query_server(msg)
                if response.opcode != OMAPI_OP_UPDATE:
                    self.module.fail_json(
                        msg="Failed to add host, ensure authentication and host parameters are valid."
                    )
                self.module.exit_json(changed=True, lease=self.unpack_facts(response.obj))
            except OmapiError as e:
                self.module.fail_json(msg=f"OMAPI error: {e}")
        # Forge update message
        else:
            response_obj = self.unpack_facts(host_response.obj)
            fields_to_update = {}

            if "ip-address" not in response_obj or response_obj["ip-address"] != self.module.params["ip"]:
                fields_to_update["ip-address"] = pack_ip(self.module.params["ip"])

            # Name cannot be changed
            if "name" not in response_obj or response_obj["name"] != self.module.params["hostname"]:
                self.module.fail_json(
                    msg=(
                        f"Changing hostname is not supported. Old was {response_obj['name']}, "
                        f"new is {self.module.params['hostname']}. Please delete host and add new."
                    )
                )

            """
            # It seems statements are not returned by OMAPI, then we cannot modify them at this moment.
            if 'statements' not in response_obj and len(self.module.params['statements']) > 0 or \
                response_obj['statements'] != self.module.params['statements']:
                with open('/tmp/omapi', 'w') as fb:
                    for (k,v) in iteritems(response_obj):
                        fb.writelines('statements: %s %s\n' % (k, v))
            """
            if len(fields_to_update) == 0:
                self.module.exit_json(changed=False, lease=response_obj)
            else:
                msg = OmapiMessage.update(host_response.handle)
                msg.update_object(fields_to_update)

            try:
                response = self.omapi.query_server(msg)
                if response.opcode != OMAPI_OP_STATUS:
                    self.module.fail_json(
                        msg="Failed to modify host, ensure authentication and host parameters are valid."
                    )
                self.module.exit_json(changed=True)
            except OmapiError as e:
                self.module.fail_json(msg=f"OMAPI error: {e}")

    def remove_host(self):
        try:
            self.omapi.del_host(self.module.params["macaddr"])
            self.module.exit_json(changed=True)
        except OmapiErrorNotFound:
            self.module.exit_json()
        except OmapiError as e:
            self.module.fail_json(msg=f"OMAPI error: {e}")


def main():
    module = AnsibleModule(
        argument_spec=dict(
            state=dict(type="str", required=True, choices=["absent", "present"]),
            host=dict(type="str", default="localhost"),
            port=dict(type="int", default=7911),
            key_name=dict(type="str", required=True),
            key=dict(type="str", required=True, no_log=True),
            macaddr=dict(type="str", required=True),
            hostname=dict(type="str", aliases=["name"]),
            ip=dict(type="str"),
            ddns=dict(type="bool", default=False),
            statements=dict(type="list", elements="str", default=[]),
        ),
        supports_check_mode=False,
    )

    if not pureomapi_found:
        module.fail_json(msg=missing_required_lib("pypureomapi"), exception=PUREOMAPI_IMP_ERR)

    if module.params["key"] is None or len(module.params["key"]) == 0:
        module.fail_json(msg="'key' parameter cannot be empty.")

    if module.params["key_name"] is None or len(module.params["key_name"]) == 0:
        module.fail_json(msg="'key_name' parameter cannot be empty.")

    host_manager = OmapiHostManager(module)
    try:
        if module.params["state"] == "present":
            host_manager.setup_host()
        elif module.params["state"] == "absent":
            host_manager.remove_host()
    except ValueError as e:
        module.fail_json(msg=f"OMAPI input value error: {e}")


if __name__ == "__main__":
    main()