# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

"""
Handle lease database updates from DHCP servers.
"""

import os
import sys

from oslo.config import cfg

from nova import config
from nova import context
from nova import db
from nova.network import rpcapi as network_rpcapi
from nova.openstack.common import importutils
from nova.openstack.common import jsonutils
from nova.openstack.common import log as logging
from nova.openstack.common import rpc

CONF = cfg.CONF
CONF.import_opt('host', 'nova.netconf')
CONF.import_opt('network_manager', 'nova.service')
LOG = logging.getLogger(__name__)


def add_lease(mac, ip_address):
    """Set the IP that was assigned by the DHCP server."""
    if CONF.fake_rabbit:
        LOG.debug(_("leasing ip"))
        network_manager = importutils.import_object(CONF.network_manager)
        network_manager.lease_fixed_ip(context.get_admin_context(),
                                       ip_address)
    else:
        api = network_rpcapi.NetworkAPI()
        api.lease_fixed_ip(context.get_admin_context(), ip_address, CONF.host)


def old_lease(mac, ip_address):
    """Called when an old lease is recognized."""
    # NOTE(vish): We assume we heard about this lease the first time.
    #             If not, we will get it the next time the lease is
    #             renewed.
    pass


def del_lease(mac, ip_address):
    """Called when a lease expires."""
    if CONF.fake_rabbit:
        LOG.debug(_("releasing ip"))
        network_manager = importutils.import_object(CONF.network_manager)
        network_manager.release_fixed_ip(context.get_admin_context(),
                                         ip_address)
    else:
        api = network_rpcapi.NetworkAPI()
        api.release_fixed_ip(context.get_admin_context(), ip_address,
                             CONF.host)


def init_leases(network_id):
    """Get the list of hosts for a network."""
    ctxt = context.get_admin_context()
    network_ref = db.network_get(ctxt, network_id)
    network_manager = importutils.import_object(CONF.network_manager)
    return network_manager.get_dhcp_leases(ctxt, network_ref)


def add_action_parsers(subparsers):
    parser = subparsers.add_parser('init')

    # NOTE(cfb): dnsmasq always passes mac, and ip. hostname
    #            is passed if known. We don't care about
    #            hostname, but argparse will complain if we
    #            do not accept it.
    for action in ['add', 'del', 'old']:
        parser = subparsers.add_parser(action)
        parser.add_argument('mac')
        parser.add_argument('ip')
        parser.add_argument('hostname', nargs='?', default='')
        parser.set_defaults(func=globals()[action + '_lease'])


CONF.register_cli_opt(
    cfg.SubCommandOpt('action',
                      title='Action options',
                      help='Available dhcpbridge options',
                      handler=add_action_parsers))


def main():
    """Parse environment and arguments and call the appropriate action."""
    try:
        config_file = os.environ['CONFIG_FILE']
    except KeyError:
        config_file = os.environ['FLAGFILE']

    config.parse_args(sys.argv,
        default_config_files=jsonutils.loads(config_file))

    logging.setup("nova")
    global LOG
    LOG = logging.getLogger('nova.dhcpbridge')

    if CONF.action.name in ['add', 'del', 'old']:
        msg = (_("Called '%(action)s' for mac '%(mac)s' with ip '%(ip)s'") %
               {"action": CONF.action.name,
                "mac": CONF.action.mac,
                "ip": CONF.action.ip})
        LOG.debug(msg)
        CONF.action.func(CONF.action.mac, CONF.action.ip)
    else:
        try:
            network_id = int(os.environ.get('NETWORK_ID'))
        except TypeError:
            LOG.error(_("Environment variable 'NETWORK_ID' must be set."))
            return(1)

        print init_leases(network_id)

    rpc.cleanup()