"""
This module interacts with an ISC DHCP Server via OMAPI.
server_ip and server_port params may be set in the minion
config or pillar:

.. code-block:: yaml

  omapi.server_ip: 127.0.0.1
  omapi.server_port: 7991

:depends: pypureomapi Python module
"""


import logging
import struct

import salt.utils.stringutils

log = logging.getLogger(__name__)


try:
    import pypureomapi as omapi

    omapi_support = True
except ImportError as e:
    omapi_support = False


def __virtual__():
    """
    Confirm pypureomapi is available.
    """
    if omapi_support:
        return "omapi"
    return (
        False,
        "The omapi execution module cannot be loaded: "
        "the pypureomapi python library is not available.",
    )


def _conn():
    server_ip = __pillar__.get(
        "omapi.server_ip", __opts__.get("omapi.server_ip", "127.0.0.1")
    )
    server_port = __pillar__.get(
        "omapi.server_port", __opts__.get("omapi.server_port", 7991)
    )
    key = __pillar__.get("omapi.key", __opts__.get("omapi.key", None))
    username = __pillar__.get("omapi.user", __opts__.get("omapi.user", None))
    if key:
        key = salt.utils.stringutils.to_bytes(key)
    if username:
        username = salt.utils.stringutils.to_bytes(username)
    return omapi.Omapi(server_ip, server_port, username=username, key=key)


def add_host(mac, name=None, ip=None, ddns=False, group=None, supersede_host=False):
    """
    Add a host object for the given mac.

    CLI Example:

    .. code-block:: bash

        salt dhcp-server omapi.add_host ab:ab:ab:ab:ab:ab name=host1

    Add ddns-hostname and a fixed-ip statements:

    .. code-block:: bash

        salt dhcp-server omapi.add_host ab:ab:ab:ab:ab:ab name=host1 ip=10.1.1.1 ddns=true
    """
    statements = ""
    o = _conn()
    msg = omapi.OmapiMessage.open(b"host")
    msg.message.append((b"create", struct.pack(b"!I", 1)))
    msg.message.append((b"exclusive", struct.pack(b"!I", 1)))
    msg.obj.append((b"hardware-address", omapi.pack_mac(mac)))
    msg.obj.append((b"hardware-type", struct.pack(b"!I", 1)))
    if ip:
        msg.obj.append((b"ip-address", omapi.pack_ip(ip)))
    if name:
        msg.obj.append((b"name", salt.utils.stringutils.to_bytes(name)))
    if group:
        msg.obj.append((b"group", salt.utils.stringutils.to_bytes(group)))
    if supersede_host:
        statements += 'option host-name "{}"; '.format(name)
    if ddns and name:
        statements += 'ddns-hostname "{}"; '.format(name)
    if statements:
        msg.obj.append((b"statements", salt.utils.stringutils.to_bytes(statements)))
    response = o.query_server(msg)
    if response.opcode != omapi.OMAPI_OP_UPDATE:
        return False
    return True


def delete_host(mac=None, name=None):
    """
    Delete the host with the given mac or name.

    CLI Examples:

    .. code-block:: bash

        salt dhcp-server omapi.delete_host name=host1
        salt dhcp-server omapi.delete_host mac=ab:ab:ab:ab:ab:ab
    """
    if not (mac or name):
        raise TypeError("At least one argument is required")
    o = _conn()
    msg = omapi.OmapiMessage.open(b"host")
    if mac:
        msg.obj.append((b"hardware-address", omapi.pack_mac(mac)))
        msg.obj.append((b"hardware-type", struct.pack(b"!I", 1)))
    if name:
        msg.obj.append((b"name", salt.utils.stringutils.to_bytes(name)))
    response = o.query_server(msg)
    if response.opcode != omapi.OMAPI_OP_UPDATE:
        return None
    if response.handle == 0:
        return False
    response = o.query_server(omapi.OmapiMessage.delete(response.handle))
    if response.opcode != omapi.OMAPI_OP_STATUS:
        return False
    return True
