# Copyright 2017 VMware, Inc.
# 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.

from oslo_config import cfg

from neutron.agent.l3 import router_info
from neutron.common import config as neutron_config  # noqa
from neutron_fwaas.db.firewall import firewall_db  # noqa
from neutron_fwaas.db.firewall import firewall_router_insertion_db \
    as fw_r_ins_db
from neutron_fwaas.services.firewall.agents.l3reference \
    import firewall_l3_agent
from neutron_lib import context as n_context
from neutron_lib.plugins import directory


class NsxvFwaasCallbacks(firewall_l3_agent.L3WithFWaaS):
    """NSX-V RPC callbacks for Firewall As A Service - V1."""
    def __init__(self):
        # The super code needs a configuration object with the neutron host
        # and an agent_mode, hich our driver doesn't use.
        neutron_conf = cfg.CONF
        neutron_conf.agent_mode = 'nsx'
        super(NsxvFwaasCallbacks, self).__init__(conf=neutron_conf)

    @property
    def core_plugin(self):
        return directory.get_plugin()

    # Override functions using the agent_api that is not used by our plugin
    def _get_router_ids_for_fw(self, context, fw, to_delete=False):
        """Return the router_ids either from fw dict or tenant routers."""
        if self._has_router_insertion_fields(fw):
            # it is a new version of plugin
            return (fw['del-router-ids'] if to_delete
                    else fw['add-router-ids'])
        else:
            return [router['id'] for router in
                self._get_routers_in_project(context, fw['tenant_id'])]

    def _get_routers_in_project(self, context, project_id):
        return self.core_plugin.get_routers(
            context,
            filters={'tenant_id': [project_id]})

    def _router_dict_to_obj(self, r):
        # The callbacks expect a router-info object
        return router_info.RouterInfo(
            None, r['id'], router=r,
            agent_conf=None,
            interface_driver=None,
            use_ipv6=False)

    def _get_router_info_list_for_tenant(self, router_ids, tenant_id):
        """Returns the list of router info objects on which to apply the fw."""
        context = n_context.get_admin_context()
        tenant_routers = self._get_routers_in_project(context, tenant_id)
        return [self._router_dict_to_obj(ri) for ri in tenant_routers
                if ri['id'] in router_ids]

    def get_fwaas_rules_for_router(self, context, router, router_id):
        """Return the list of (translated) fwaas rules for this router."""
        if not self.fwaas_enabled:
            return []

        ctx_elevated = context.elevated()

        # get all the relevant router info
        # ("router" does not have all the fields)
        router_data = self.core_plugin.get_router(ctx_elevated, router['id'])
        if not router_data:
            return []
        if router_data.get('distributed'):
            # in case of distributed router router['id'] is the id of the
            # neutron router
            # and router_id is the plr/tlr (the one that is being updated)
            if router_id == router['id']:
                # Do not add firewall rules on the tlr router.
                return []
        if router_data.get('router_type') == 'shared':
            # Currently there is no FWaaS support for shared routers
            return []

        # Exclusive router or PLR
        fw_id = self._get_router_firewall_id(ctx_elevated, router['id'])
        if fw_id:
            return self._get_fw_applicable_rules(ctx_elevated, fw_id)
        return []

    # TODO(asarfaty): add this api to fwaas firewall-router-insertion-db
    def _get_router_firewall_id(self, context, router_id):
        entry = context.session.query(
            fw_r_ins_db.FirewallRouterAssociation).filter_by(
            router_id=router_id).first()
        if entry:
            return entry.fw_id

    def _get_fw_applicable_rules(self, context, fw_id):
        fw_list = self.fwplugin_rpc.get_firewalls_for_tenant(context)
        for fw in fw_list:
            if fw['id'] == fw_id:
                return self.fwaas_driver.get_firewall_translated_rules(fw)
        return []