# Copyright 2014 DreamHost, LLC
#
# Author: DreamHost, LLC
#
# 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.

import re

import netaddr
from oslo_config import cfg

from neutron.api.v2 import attributes
from neutron.common import constants as neutron_constants
from neutron.db import l3_db
from neutron.db import models_v2
from neutron.plugins.ml2 import plugin
from neutron.services.l3_router import l3_router_plugin

from astara_neutron.plugins import decorators as astara


AKANDA_PORT_NAME_RE = re.compile(
    '^(ASTARA|AKANDA):(MGT|VRRP):[0-9a-f]{8}(-[0-9a-f]{4}){3}-[0-9a-f]{12}$'
)


class Ml2Plugin(plugin.Ml2Plugin):

    _supported_extension_aliases = (
        plugin.Ml2Plugin._supported_extension_aliases +
        ["dhrouterstatus", "byonf"]
    )

    disabled_extensions = [
        neutron_constants.DHCP_AGENT_SCHEDULER_EXT_ALIAS,
        neutron_constants.LBAAS_AGENT_SCHEDULER_EXT_ALIAS
    ]
    for ext in disabled_extensions:
        try:
            _supported_extension_aliases.remove(ext)
        except ValueError:
            pass

    @astara.auto_add_ipv6_subnet
    def create_network(self, context, network):
        return super(Ml2Plugin, self).create_network(context, network)

    @astara.auto_add_subnet_to_router
    def create_subnet(self, context, subnet):
        return super(Ml2Plugin, self).create_subnet(context, subnet)

    @astara.sync_subnet_gateway_port
    def update_subnet(self, context, id, subnet):
        return super(Ml2Plugin, self).update_subnet(
            context, id, subnet)

    # Nova is unhappy when the port does not have any IPs, so we're going
    # to add the v6 link local dummy data.
    # TODO(mark): limit this lie to service user
    def _make_port_dict(self, port, fields=None, process_extensions=True):
        res = super(Ml2Plugin, self)._make_port_dict(
            port,
            fields,
            process_extensions
        )

        if not res.get('fixed_ips') and res.get('mac_address'):
            v6_link_local = netaddr.EUI(res['mac_address']).ipv6_link_local()

            res['fixed_ips'] = [
                {
                    'subnet_id': '00000000-0000-0000-0000-000000000000',
                    'ip_address': str(v6_link_local)
                }
            ]
        return res

    def _select_dhcp_ips_for_network_ids(self, context, network_ids):
        ips = super(Ml2Plugin, self)._select_dhcp_ips_for_network_ids(
            context,
            network_ids
        )

        # allow DHCP replies from router interfaces since they're combined in
        # Astara appliances. Minimal impact if another appliance is used.
        query = context.session.query(models_v2.Port.mac_address,
                                      models_v2.Port.network_id,
                                      models_v2.IPAllocation.ip_address)
        query = query.join(models_v2.IPAllocation)
        query = query.filter(models_v2.Port.network_id.in_(network_ids))
        owner = neutron_constants.DEVICE_OWNER_ROUTER_INTF
        query = query.filter(models_v2.Port.device_owner == owner)

        for mac_address, network_id, ip in query:
            if (netaddr.IPAddress(ip).version == 6 and not
               netaddr.IPAddress(ip).is_link_local()):

                ip = str(netaddr.EUI(mac_address).ipv6_link_local())
            if ip not in ips[network_id]:
                ips[network_id].append(ip)

        return ips

    # TODO(markmcclain) add upstream ability to remove port-security
    # workaround it for now by filtering out Akanda ports
    def get_ports_from_devices(self, context, devices):
        "this wrapper removes Akanda VRRP ports since they are router ports"
        ports = super(Ml2Plugin, self).get_ports_from_devices(context, devices)
        return (
            port
            for port in ports
            if port and not AKANDA_PORT_NAME_RE.match(port['name'])
        )


class L3RouterPlugin(l3_router_plugin.L3RouterPlugin):

    # An issue in neutron is making this class inheriting some
    # methods from l3_dvr_db.L3_NAT_with_dvr_db_mixin.As a workaround
    # we force it to use the original methods in the
    # l3_db.L3_NAT_db_mixin class.
    get_sync_data = l3_db.L3_NAT_db_mixin.get_sync_data
    add_router_interface = l3_db.L3_NAT_db_mixin.add_router_interface
    remove_router_interface = l3_db.L3_NAT_db_mixin.remove_router_interface

    # call this directly instead of through class hierarchy, to avoid
    # the l3_hamode_db from doing agent-based HA setup and checks
    _create_router = l3_db.L3_NAT_dbonly_mixin.create_router

    def list_routers_on_l3_agent(self, context, agent_id):
        return {
            'routers': self.get_routers(context),
        }

    def list_active_sync_routers_on_active_l3_agent(
            self, context, host, router_ids):
        # Override L3AgentSchedulerDbMixin method
        filters = {}
        if router_ids:
            filters['id'] = router_ids
        routers = self.get_routers(context, filters=filters)
        new_router_ids = [r['id'] for r in routers]
        if new_router_ids:
            return self.get_sync_data(
                context,
                router_ids=new_router_ids,
                active=True,
            )
        return []

    @classmethod
    def _is_ha(cls, router):
        ha = router.get('ha')
        if not attributes.is_attr_set(ha):
            ha = cfg.CONF.l3_ha
        return ha

    def create_router(self, context, router):
        router['router']['ha'] = self._is_ha(router['router'])
        return self._create_router(context, router)

if neutron_constants.L3_AGENT_SCHEDULER_EXT_ALIAS in \
        L3RouterPlugin.supported_extension_aliases:
    L3RouterPlugin.supported_extension_aliases.remove(
        neutron_constants.L3_AGENT_SCHEDULER_EXT_ALIAS
    )