# (c) 2016 Red Hat Inc.
# (c) 2017 Ansible Project
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import absolute_import, division, print_function

__metaclass__ = type

DOCUMENTATION = """
author: Ansible Networking Team
connection: netconf
short_description: Provides a persistent connection using the netconf protocol
description:
- This connection plugin provides a connection to remote devices over the SSH NETCONF
  subsystem.  This connection plugin is typically used by network devices for sending
  and receiving RPC calls over NETCONF.
- Note this connection plugin requires ncclient to be installed on the local Ansible
  controller.
version_added: 1.0.0
requirements:
- ncclient
options:
  host:
    description:
    - Specifies the remote device FQDN or IP address to establish the SSH connection
      to.
    default: inventory_hostname
    vars:
    - name: ansible_host
  port:
    type: int
    description:
    - Specifies the port on the remote device that listens for connections when establishing
      the SSH connection.
    default: 830
    ini:
    - section: defaults
      key: remote_port
    env:
    - name: ANSIBLE_REMOTE_PORT
    vars:
    - name: ansible_port
  network_os:
    description:
    - Configures the device platform network operating system.  This value is used
      to load a device specific netconf plugin.  If this option is not configured
      (or set to C(auto)), then Ansible will attempt to guess the correct network_os
      to use. If it can not guess a network_os correctly it will use C(default).
    vars:
    - name: ansible_network_os
  remote_user:
    description:
    - The username used to authenticate to the remote device when the SSH connection
      is first established.  If the remote_user is not specified, the connection will
      use the username of the logged in user.
    - Can be configured from the CLI via the C(--user) or C(-u) options.
    ini:
    - section: defaults
      key: remote_user
    env:
    - name: ANSIBLE_REMOTE_USER
    vars:
    - name: ansible_user
  password:
    description:
    - Configures the user password used to authenticate to the remote device when
      first establishing the SSH connection.
    vars:
    - name: ansible_password
    - name: ansible_ssh_pass
    - name: ansible_ssh_password
    - name: ansible_netconf_password
  private_key_file:
    description:
    - The private SSH key or certificate file used to authenticate to the remote device
      when first establishing the SSH connection.
    ini:
    - section: defaults
      key: private_key_file
    env:
    - name: ANSIBLE_PRIVATE_KEY_FILE
    vars:
    - name: ansible_private_key_file
  look_for_keys:
    default: true
    description:
    - Enables looking for ssh keys in the usual locations for ssh keys (e.g. :file:`~/.ssh/id_*`).
    env:
    - name: ANSIBLE_PARAMIKO_LOOK_FOR_KEYS
    ini:
    - section: paramiko_connection
      key: look_for_keys
    type: boolean
  host_key_checking:
    description: Set this to "False" if you want to avoid host key checking by the
      underlying tools Ansible uses to connect to the host
    type: boolean
    default: true
    env:
    - name: ANSIBLE_HOST_KEY_CHECKING
    - name: ANSIBLE_SSH_HOST_KEY_CHECKING
    - name: ANSIBLE_NETCONF_HOST_KEY_CHECKING
    ini:
    - section: defaults
      key: host_key_checking
    - section: paramiko_connection
      key: host_key_checking
    vars:
    - name: ansible_host_key_checking
    - name: ansible_ssh_host_key_checking
    - name: ansible_netconf_host_key_checking
  persistent_connect_timeout:
    type: int
    description:
    - Configures, in seconds, the amount of time to wait when trying to initially
      establish a persistent connection.  If this value expires before the connection
      to the remote device is completed, the connection will fail.
    default: 30
    ini:
    - section: persistent_connection
      key: connect_timeout
    env:
    - name: ANSIBLE_PERSISTENT_CONNECT_TIMEOUT
    vars:
    - name: ansible_connect_timeout
  persistent_command_timeout:
    type: int
    description:
    - Configures, in seconds, the amount of time to wait for a command to return from
      the remote device.  If this timer is exceeded before the command returns, the
      connection plugin will raise an exception and close.
    default: 30
    ini:
    - section: persistent_connection
      key: command_timeout
    env:
    - name: ANSIBLE_PERSISTENT_COMMAND_TIMEOUT
    vars:
    - name: ansible_command_timeout
  netconf_ssh_config:
    description:
    - This variable is used to enable bastion/jump host with netconf connection. If
      set to True the bastion/jump host ssh settings should be present in ~/.ssh/config
      file, alternatively it can be set to custom ssh configuration file path to read
      the bastion/jump host settings.
    ini:
    - section: netconf_connection
      key: ssh_config
    env:
    - name: ANSIBLE_NETCONF_SSH_CONFIG
    vars:
    - name: ansible_netconf_ssh_config
  persistent_log_messages:
    type: boolean
    description:
    - This flag will enable logging the command executed and response received from
      target device in the ansible log file. For this option to work 'log_path' ansible
      configuration option is required to be set to a file path with write access.
    - Be sure to fully understand the security implications of enabling this option
      as it could create a security vulnerability by logging sensitive information
      in log file.
    default: false
    ini:
    - section: persistent_connection
      key: log_messages
    env:
    - name: ANSIBLE_PERSISTENT_LOG_MESSAGES
    vars:
    - name: ansible_persistent_log_messages
"""

import os
import logging
import json

from ansible.errors import AnsibleConnectionFailure, AnsibleError
from ansible.module_utils._text import to_bytes, to_native, to_text
from ansible.module_utils.basic import missing_required_lib
from ansible.module_utils.parsing.convert_bool import (
    BOOLEANS_TRUE,
    BOOLEANS_FALSE,
)
from ansible.plugins.loader import netconf_loader
from ansible.plugins.connection import NetworkConnectionBase, ensure_connect

try:
    from ncclient import manager
    from ncclient.operations import RPCError
    from ncclient.transport.errors import (
        AuthenticationError,
        SSHUnknownHostError,
    )
    from ncclient.xml_ import to_ele, to_xml

    HAS_NCCLIENT = True
    NCCLIENT_IMP_ERR = None
except (
    ImportError,
    AttributeError,
) as err:  # paramiko and gssapi are incompatible and raise AttributeError not ImportError
    HAS_NCCLIENT = False
    NCCLIENT_IMP_ERR = err

logging.getLogger("ncclient").setLevel(logging.INFO)


class Connection(NetworkConnectionBase):
    """NetConf connections"""

    transport = "ansible.netcommon.netconf"
    has_pipelining = False

    def __init__(self, play_context, new_stdin, *args, **kwargs):
        super(Connection, self).__init__(
            play_context, new_stdin, *args, **kwargs
        )

        # If network_os is not specified then set the network os to auto
        # This will be used to trigger the use of guess_network_os when connecting.
        self._network_os = self._network_os or "auto"

        self.netconf = netconf_loader.get(self._network_os, self)
        if self.netconf:
            self._sub_plugin = {
                "type": "netconf",
                "name": self.netconf._load_name,
                "obj": self.netconf,
            }
            self.queue_message(
                "vvvv",
                "loaded netconf plugin %s from path %s for network_os %s"
                % (
                    self.netconf._load_name,
                    self.netconf._original_path,
                    self._network_os,
                ),
            )
        else:
            self.netconf = netconf_loader.get("default", self)
            self._sub_plugin = {
                "type": "netconf",
                "name": "default",
                "obj": self.netconf,
            }
            self.queue_message(
                "display",
                "unable to load netconf plugin for network_os %s, falling back to default plugin"
                % self._network_os,
            )

        self.queue_message("log", "network_os is set to %s" % self._network_os)
        self._manager = None
        self.key_filename = None
        self._ssh_config = None

    def exec_command(self, cmd, in_data=None, sudoable=True):
        """Sends the request to the node and returns the reply
        The method accepts two forms of request.  The first form is as a byte
        string that represents xml string be send over netconf session.
        The second form is a json-rpc (2.0) byte string.
        """
        if self._manager:
            # to_ele operates on native strings
            request = to_ele(to_native(cmd, errors="surrogate_or_strict"))

            if request is None:
                return "unable to parse request"

            try:
                reply = self._manager.rpc(request)
            except RPCError as exc:
                error = self.internal_error(
                    data=to_text(to_xml(exc.xml), errors="surrogate_or_strict")
                )
                return json.dumps(error)

            return reply.data_xml
        else:
            return super(Connection, self).exec_command(cmd, in_data, sudoable)

    @property
    @ensure_connect
    def manager(self):
        return self._manager

    def _connect(self):
        if not HAS_NCCLIENT:
            raise AnsibleError(
                "%s: %s"
                % (
                    missing_required_lib("ncclient"),
                    to_native(NCCLIENT_IMP_ERR),
                )
            )

        self.queue_message("log", "ssh connection done, starting ncclient")

        allow_agent = True
        if self._play_context.password is not None:
            allow_agent = False
        setattr(self._play_context, "allow_agent", allow_agent)

        self.key_filename = (
            self._play_context.private_key_file
            or self.get_option("private_key_file")
        )
        if self.key_filename:
            self.key_filename = str(os.path.expanduser(self.key_filename))

        self._ssh_config = self.get_option("netconf_ssh_config")
        if self._ssh_config in BOOLEANS_TRUE:
            self._ssh_config = True
        elif self._ssh_config in BOOLEANS_FALSE:
            self._ssh_config = None

        # Try to guess the network_os if the network_os is set to auto
        if self._network_os == "auto":
            for cls in netconf_loader.all(class_only=True):
                network_os = cls.guess_network_os(self)
                if network_os:
                    self.queue_message(
                        "vvv", "discovered network_os %s" % network_os
                    )
                    self._network_os = network_os

        # If we have tried to detect the network_os but were unable to i.e. network_os is still 'auto'
        # then use default as the network_os

        if self._network_os == "auto":
            # Network os not discovered. Set it to default
            self.queue_message(
                "vvv",
                "Unable to discover network_os. Falling back to default.",
            )
            self._network_os = "default"
        try:
            ncclient_device_handler = self.netconf.get_option(
                "ncclient_device_handler"
            )
        except KeyError:
            ncclient_device_handler = "default"
        self.queue_message(
            "vvv",
            "identified ncclient device handler: %s."
            % ncclient_device_handler,
        )
        device_params = {"name": ncclient_device_handler}

        try:
            port = self._play_context.port or 830
            self.queue_message(
                "vvv",
                "ESTABLISH NETCONF SSH CONNECTION FOR USER: %s on PORT %s TO %s WITH SSH_CONFIG = %s"
                % (
                    self._play_context.remote_user,
                    port,
                    self._play_context.remote_addr,
                    self._ssh_config,
                ),
            )
            self._manager = manager.connect(
                host=self._play_context.remote_addr,
                port=port,
                username=self._play_context.remote_user,
                password=self._play_context.password,
                key_filename=self.key_filename,
                hostkey_verify=self.get_option("host_key_checking"),
                look_for_keys=self.get_option("look_for_keys"),
                device_params=device_params,
                allow_agent=self._play_context.allow_agent,
                timeout=self.get_option("persistent_connect_timeout"),
                ssh_config=self._ssh_config,
            )

            self._manager._timeout = self.get_option(
                "persistent_command_timeout"
            )
        except SSHUnknownHostError as exc:
            raise AnsibleConnectionFailure(to_native(exc))
        except AuthenticationError as exc:
            if str(exc).startswith("FileNotFoundError"):
                raise AnsibleError(
                    "Encountered FileNotFoundError in ncclient connect. Does {0} exist?".format(
                        self.key_filename
                    )
                )
            raise
        except ImportError:
            raise AnsibleError(
                "connection=netconf is not supported on {0}".format(
                    self._network_os
                )
            )

        if not self._manager.connected:
            return 1, b"", b"not connected"

        self.queue_message(
            "log", "ncclient manager object created successfully"
        )

        self._connected = True

        super(Connection, self)._connect()

        return (
            0,
            to_bytes(self._manager.session_id, errors="surrogate_or_strict"),
            b"",
        )

    def close(self):
        if self._manager:
            self._manager.close_session()
        super(Connection, self).close()
