# Copyright (c) 2012 OpenStack Foundation.
#
# 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.

from oslo.config import cfg
from sqlalchemy.orm import exc

from neutron.api.v2 import attributes
from neutron.common import constants
from neutron.common import utils
from neutron.extensions import portbindings
from neutron import manager
from neutron.openstack.common import log as logging


LOG = logging.getLogger(__name__)


class DhcpRpcCallbackMixin(object):
    """A mix-in that enable DHCP agent support in plugin implementations."""

    def _get_active_networks(self, context, **kwargs):
        """Retrieve and return a list of the active networks."""
        host = kwargs.get('host')
        plugin = manager.NeutronManager.get_plugin()
        if utils.is_extension_supported(
            plugin, constants.DHCP_AGENT_SCHEDULER_EXT_ALIAS):
            if cfg.CONF.network_auto_schedule:
                plugin.auto_schedule_networks(context, host)
            nets = plugin.list_active_networks_on_active_dhcp_agent(
                context, host)
        else:
            filters = dict(admin_state_up=[True])
            nets = plugin.get_networks(context, filters=filters)
        return nets

    def get_active_networks(self, context, **kwargs):
        """Retrieve and return a list of the active network ids."""
        # NOTE(arosen): This method is no longer used by the DHCP agent but is
        # left so that neutron-dhcp-agents will still continue to work if
        # neutron-server is upgraded and not the agent.
        host = kwargs.get('host')
        LOG.debug(_('get_active_networks requested from %s'), host)
        nets = self._get_active_networks(context, **kwargs)
        return [net['id'] for net in nets]

    def get_active_networks_info(self, context, **kwargs):
        """Returns all the networks/subnets/ports in system."""
        host = kwargs.get('host')
        LOG.debug(_('get_active_networks_info from %s'), host)
        networks = self._get_active_networks(context, **kwargs)
        plugin = manager.NeutronManager.get_plugin()
        filters = {'network_id': [network['id'] for network in networks]}
        ports = plugin.get_ports(context, filters=filters)
        filters['enable_dhcp'] = [True]
        subnets = plugin.get_subnets(context, filters=filters)

        for network in networks:
            network['subnets'] = [subnet for subnet in subnets
                                  if subnet['network_id'] == network['id']]
            network['ports'] = [port for port in ports
                                if port['network_id'] == network['id']]

        return networks

    def get_network_info(self, context, **kwargs):
        """Retrieve and return a extended information about a network."""
        network_id = kwargs.get('network_id')
        host = kwargs.get('host')
        LOG.debug(_('Network %(network_id)s requested from '
                    '%(host)s'), {'network_id': network_id,
                                  'host': host})
        plugin = manager.NeutronManager.get_plugin()
        network = plugin.get_network(context, network_id)

        filters = dict(network_id=[network_id])
        network['subnets'] = plugin.get_subnets(context, filters=filters)
        network['ports'] = plugin.get_ports(context, filters=filters)
        return network

    def get_dhcp_port(self, context, **kwargs):
        """Allocate a DHCP port for the host and return port information.

        This method will re-use an existing port if one already exists.  When a
        port is re-used, the fixed_ip allocation will be updated to the current
        network state.

        """
        # NOTE(arosen): This method is no longer used by the DHCP agent but is
        # left so that neutron-dhcp-agents will still continue to work if
        # neutron-server is upgraded and not the agent.

        host = kwargs.get('host')
        network_id = kwargs.get('network_id')
        device_id = kwargs.get('device_id')
        # There could be more than one dhcp server per network, so create
        # a device id that combines host and network ids

        LOG.debug(_('Port %(device_id)s for %(network_id)s requested from '
                    '%(host)s'), {'device_id': device_id,
                                  'network_id': network_id,
                                  'host': host})
        plugin = manager.NeutronManager.get_plugin()
        retval = None

        filters = dict(network_id=[network_id])
        subnets = dict([(s['id'], s) for s in
                        plugin.get_subnets(context, filters=filters)])

        dhcp_enabled_subnet_ids = [s['id'] for s in
                                   subnets.values() if s['enable_dhcp']]

        try:
            filters = dict(network_id=[network_id], device_id=[device_id])
            ports = plugin.get_ports(context, filters=filters)
            if ports:
                # Ensure that fixed_ips cover all dhcp_enabled subnets.
                port = ports[0]
                for fixed_ip in port['fixed_ips']:
                    if fixed_ip['subnet_id'] in dhcp_enabled_subnet_ids:
                        dhcp_enabled_subnet_ids.remove(fixed_ip['subnet_id'])
                port['fixed_ips'].extend(
                    [dict(subnet_id=s) for s in dhcp_enabled_subnet_ids])

                retval = plugin.update_port(context, port['id'],
                                            dict(port=port))

        except exc.NoResultFound:
            pass

        if retval is None:
            # No previous port exists, so create a new one.
            LOG.debug(_('DHCP port %(device_id)s on network %(network_id)s '
                        'does not exist on %(host)s'),
                      {'device_id': device_id,
                       'network_id': network_id,
                       'host': host})

            network = plugin.get_network(context, network_id)

            port_dict = dict(
                admin_state_up=True,
                device_id=device_id,
                network_id=network_id,
                tenant_id=network['tenant_id'],
                mac_address=attributes.ATTR_NOT_SPECIFIED,
                name='',
                device_owner='network:dhcp',
                fixed_ips=[dict(subnet_id=s) for s in dhcp_enabled_subnet_ids])

            retval = plugin.create_port(context, dict(port=port_dict))

        # Convert subnet_id to subnet dict
        for fixed_ip in retval['fixed_ips']:
            subnet_id = fixed_ip.pop('subnet_id')
            fixed_ip['subnet'] = subnets[subnet_id]

        return retval

    def release_dhcp_port(self, context, **kwargs):
        """Release the port currently being used by a DHCP agent."""
        host = kwargs.get('host')
        network_id = kwargs.get('network_id')
        device_id = kwargs.get('device_id')

        LOG.debug(_('DHCP port deletion for %(network_id)s request from '
                    '%(host)s'),
                  {'network_id': network_id, 'host': host})
        plugin = manager.NeutronManager.get_plugin()
        filters = dict(network_id=[network_id], device_id=[device_id])
        ports = plugin.get_ports(context, filters=filters)

        if ports:
            plugin.delete_port(context, ports[0]['id'])

    def release_port_fixed_ip(self, context, **kwargs):
        """Release the fixed_ip associated the subnet on a port."""
        host = kwargs.get('host')
        network_id = kwargs.get('network_id')
        device_id = kwargs.get('device_id')
        subnet_id = kwargs.get('subnet_id')

        LOG.debug(_('DHCP port remove fixed_ip for %(subnet_id)s request '
                    'from %(host)s'),
                  {'subnet_id': subnet_id, 'host': host})
        plugin = manager.NeutronManager.get_plugin()
        filters = dict(network_id=[network_id], device_id=[device_id])
        ports = plugin.get_ports(context, filters=filters)

        if ports:
            port = ports[0]

            fixed_ips = port.get('fixed_ips', [])
            for i in range(len(fixed_ips)):
                if fixed_ips[i]['subnet_id'] == subnet_id:
                    del fixed_ips[i]
                    break
            plugin.update_port(context, port['id'], dict(port=port))

    def update_lease_expiration(self, context, **kwargs):
        """Release the fixed_ip associated the subnet on a port."""
        # NOTE(arosen): This method is no longer used by the DHCP agent but is
        # left so that neutron-dhcp-agents will still continue to work if
        # neutron-server is upgraded and not the agent.
        host = kwargs.get('host')

        LOG.warning(_('Updating lease expiration is now deprecated. Issued  '
                      'from host %s.'), host)

    def create_dhcp_port(self, context, **kwargs):
        """Create the dhcp port."""
        host = kwargs.get('host')
        port = kwargs.get('port')
        LOG.debug(_('Create dhcp port %(port)s '
                    'from %(host)s.'),
                  {'port': port,
                   'host': host})

        port['port']['device_owner'] = constants.DEVICE_OWNER_DHCP
        port['port'][portbindings.HOST_ID] = host
        if 'mac_address' not in port['port']:
            port['port']['mac_address'] = attributes.ATTR_NOT_SPECIFIED
        plugin = manager.NeutronManager.get_plugin()
        return plugin.create_port(context, port)

    def update_dhcp_port(self, context, **kwargs):
        """Update the dhcp port."""
        host = kwargs.get('host')
        port_id = kwargs.get('port_id')
        port = kwargs.get('port')
        LOG.debug(_('Update dhcp port %(port)s '
                    'from %(host)s.'),
                  {'port': port,
                   'host': host})
        plugin = manager.NeutronManager.get_plugin()
        return plugin.update_port(context, port_id, port)
