# Copyright (c) 2014 Cisco Systems 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.
#
# @author: Arvind Somya (asomya@cisco.com), Cisco Systems Inc.

from apicapi import apic_manager
from apicapi import exceptions as exc
from keystoneclient.v2_0 import client as keyclient
import netaddr
from oslo.config import cfg

from neutron.common import constants as n_constants
from neutron.openstack.common import lockutils
from neutron.openstack.common import log
from neutron.plugins.common import constants
from neutron.plugins.ml2 import driver_api as api
from neutron.plugins.ml2.drivers.cisco.apic import apic_model
from neutron.plugins.ml2.drivers.cisco.apic import apic_sync
from neutron.plugins.ml2.drivers.cisco.apic import config
from neutron.plugins.ml2 import models


LOG = log.getLogger(__name__)


class APICMechanismDriver(api.MechanismDriver):

    @staticmethod
    def get_apic_manager(client=True):
        apic_config = cfg.CONF.ml2_cisco_apic
        network_config = {
            'vlan_ranges': cfg.CONF.ml2_type_vlan.network_vlan_ranges,
            'switch_dict': config.create_switch_dictionary(),
            'vpc_dict': config.create_vpc_dictionary(),
            'external_network_dict':
                config.create_external_network_dictionary(),
        }
        apic_system_id = cfg.CONF.apic_system_id
        keyclient_param = keyclient if client else None
        keystone_authtoken = cfg.CONF.keystone_authtoken if client else None
        return apic_manager.APICManager(apic_model.ApicDbModel(), log,
                                        network_config, apic_config,
                                        keyclient_param, keystone_authtoken,
                                        apic_system_id)

    @staticmethod
    def get_base_synchronizer(inst):
        apic_config = cfg.CONF.ml2_cisco_apic
        return apic_sync.ApicBaseSynchronizer(inst,
                                              apic_config.apic_sync_interval)

    @staticmethod
    def get_router_synchronizer(inst):
        apic_config = cfg.CONF.ml2_cisco_apic
        return apic_sync.ApicRouterSynchronizer(inst,
                                                apic_config.apic_sync_interval)

    def initialize(self):
        # initialize apic
        self.apic_manager = APICMechanismDriver.get_apic_manager()
        self.name_mapper = self.apic_manager.apic_mapper
        self.synchronizer = None
        self.apic_manager.ensure_infra_created_on_apic()
        self.apic_manager.ensure_bgp_pod_policy_created_on_apic()

    def sync_init(f):
        def inner(inst, *args, **kwargs):
            if not inst.synchronizer:
                inst.synchronizer = (
                    APICMechanismDriver.get_base_synchronizer(inst))
                inst.synchronizer.sync_base()
            return f(inst, *args, **kwargs)
        return inner

    @lockutils.synchronized('apic-portlock')
    def _perform_path_port_operations(self, context, port):
        # Get network
        network_id = context.network.current['id']
        anetwork_id = self.name_mapper.network(context, network_id)
        # Get tenant details from port context
        tenant_id = context.current['tenant_id']
        tenant_id = self.name_mapper.tenant(context, tenant_id)

        # Get segmentation id
        if not context.bound_segment:
            LOG.debug("Port %s is not bound to a segment", port)
            return
        seg = None
        if (context.bound_segment.get(api.NETWORK_TYPE)
                in [constants.TYPE_VLAN]):
            seg = context.bound_segment.get(api.SEGMENTATION_ID)
        # hosts on which this vlan is provisioned
        host = context.host
        # Create a static path attachment for the host/epg/switchport combo
        with self.apic_manager.apic.transaction() as trs:
            self.apic_manager.ensure_path_created_for_port(
                tenant_id, anetwork_id, host, seg, transaction=trs)

    def _perform_gw_port_operations(self, context, port):
        router_id = port.get('device_id')
        network = context.network.current
        anetwork_id = self.name_mapper.network(context, network['id'])
        router_info = self.apic_manager.ext_net_dict.get(network['name'])

        if router_id and router_info:
            address = router_info['cidr_exposed']
            next_hop = router_info['gateway_ip']
            encap = router_info.get('encap')  # No encap if None
            switch = router_info['switch']
            module, sport = router_info['port'].split('/')
            with self.apic_manager.apic.transaction() as trs:
                # Get/Create contract
                arouter_id = self.name_mapper.router(context, router_id)
                cid = self.apic_manager.get_router_contract(arouter_id)
                # Ensure that the external ctx exists
                self.apic_manager.ensure_context_enforced()
                # Create External Routed Network and configure it
                self.apic_manager.ensure_external_routed_network_created(
                    anetwork_id, transaction=trs)
                self.apic_manager.ensure_logical_node_profile_created(
                    anetwork_id, switch, module, sport, encap,
                    address, transaction=trs)
                self.apic_manager.ensure_static_route_created(
                    anetwork_id, switch, next_hop, transaction=trs)
                self.apic_manager.ensure_external_epg_created(
                    anetwork_id, transaction=trs)
                self.apic_manager.ensure_external_epg_consumed_contract(
                    anetwork_id, cid, transaction=trs)
                self.apic_manager.ensure_external_epg_provided_contract(
                    anetwork_id, cid, transaction=trs)

    def _perform_port_operations(self, context):
        # Get port
        port = context.current
        # Check if a compute port
        if port.get('device_owner', '').startswith('compute'):
            self._perform_path_port_operations(context, port)
        elif port.get('device_owner') == n_constants.DEVICE_OWNER_ROUTER_GW:
            self._perform_gw_port_operations(context, port)
        elif port.get('device_owner') == n_constants.DEVICE_OWNER_DHCP:
            self._perform_path_port_operations(context, port)

    def _delete_contract(self, context):
        port = context.current
        network_id = self.name_mapper.network(
            context, context.network.current['id'])
        arouter_id = self.name_mapper.router(context,
                                             port.get('device_id'))
        self.apic_manager.delete_external_epg_contract(arouter_id,
                                                       network_id)

    def _get_active_path_count(self, context):
        return context._plugin_context.session.query(
            models.PortBinding).filter_by(
                host=context.host, segment=context._binding.segment).count()

    @lockutils.synchronized('apic-portlock')
    def _delete_port_path(self, context, atenant_id, anetwork_id):
        if not self._get_active_path_count(context):
            self.apic_manager.ensure_path_deleted_for_port(
                atenant_id, anetwork_id,
                context.host)

    def _delete_path_if_last(self, context):
        if not self._get_active_path_count(context):
            tenant_id = context.current['tenant_id']
            atenant_id = self.name_mapper.tenant(context, tenant_id)
            network_id = context.network.current['id']
            anetwork_id = self.name_mapper.network(context, network_id)
            self._delete_port_path(context, atenant_id, anetwork_id)

    def _get_subnet_info(self, context, subnet):
        tenant_id = subnet['tenant_id']
        network_id = subnet['network_id']
        network = context._plugin.get_network(context._plugin_context,
                                              network_id)
        if not network.get('router:external'):
            cidr = netaddr.IPNetwork(subnet['cidr'])
            gateway_ip = '%s/%s' % (subnet['gateway_ip'], str(cidr.prefixlen))

            # Convert to APIC IDs
            tenant_id = self.name_mapper.tenant(context, tenant_id)
            network_id = self.name_mapper.network(context, network_id)
            return tenant_id, network_id, gateway_ip

    @sync_init
    def create_port_postcommit(self, context):
        self._perform_port_operations(context)

    def update_port_precommit(self, context):
        orig = context.original
        curr = context.current
        if (orig['device_owner'] != curr['device_owner']
                or orig['device_id'] != curr['device_id']):
            raise exc.ApicOperationNotSupported(
                resource='Port', msg='Port device owner and id cannot be '
                                     'changed.')

    @sync_init
    def update_port_postcommit(self, context):
        self._perform_port_operations(context)

    def delete_port_postcommit(self, context):
        port = context.current
        # Check if a compute port
        if port.get('device_owner', '').startswith('compute'):
            self._delete_path_if_last(context)
        elif port.get('device_owner') == n_constants.DEVICE_OWNER_ROUTER_GW:
            self._delete_contract(context)
        elif port.get('device_owner') == n_constants.DEVICE_OWNER_DHCP:
            self._delete_path_if_last(context)

    @sync_init
    def create_network_postcommit(self, context):
        if not context.current.get('router:external'):
            tenant_id = context.current['tenant_id']
            network_id = context.current['id']

            # Convert to APIC IDs
            tenant_id = self.name_mapper.tenant(context, tenant_id)
            network_id = self.name_mapper.network(context, network_id)

            # Create BD and EPG for this network
            with self.apic_manager.apic.transaction() as trs:
                self.apic_manager.ensure_bd_created_on_apic(tenant_id,
                                                            network_id,
                                                            transaction=trs)
                self.apic_manager.ensure_epg_created(
                    tenant_id, network_id, transaction=trs)

    @sync_init
    def update_network_postcommit(self, context):
        super(APICMechanismDriver, self).update_network_postcommit(context)

    def delete_network_postcommit(self, context):
        if not context.current.get('router:external'):
            tenant_id = context.current['tenant_id']
            network_id = context.current['id']

            # Convert to APIC IDs
            tenant_id = self.name_mapper.tenant(context, tenant_id)
            network_id = self.name_mapper.network(context, network_id)

            # Delete BD and EPG for this network
            with self.apic_manager.apic.transaction() as trs:
                self.apic_manager.delete_epg_for_network(tenant_id, network_id,
                                                         transaction=trs)
                self.apic_manager.delete_bd_on_apic(tenant_id, network_id,
                                                    transaction=trs)
        else:
            network_name = context.current['name']
            if self.apic_manager.ext_net_dict.get(network_name):
                network_id = self.name_mapper.network(context,
                                                      context.current['id'])
                self.apic_manager.delete_external_routed_network(network_id)

    @sync_init
    def create_subnet_postcommit(self, context):
        info = self._get_subnet_info(context, context.current)
        if info:
            tenant_id, network_id, gateway_ip = info
            # Create subnet on BD
            self.apic_manager.ensure_subnet_created_on_apic(
                tenant_id, network_id, gateway_ip)

    @sync_init
    def update_subnet_postcommit(self, context):
        if context.current['gateway_ip'] != context.original['gateway_ip']:
            with self.apic_manager.apic.transaction() as trs:
                info = self._get_subnet_info(context, context.original)
                if info:
                    tenant_id, network_id, gateway_ip = info
                    # Delete subnet
                    self.apic_manager.ensure_subnet_deleted_on_apic(
                        tenant_id, network_id, gateway_ip, transaction=trs)
                info = self._get_subnet_info(context, context.current)
                if info:
                    tenant_id, network_id, gateway_ip = info
                    # Create subnet
                    self.apic_manager.ensure_subnet_created_on_apic(
                        tenant_id, network_id, gateway_ip, transaction=trs)

    def delete_subnet_postcommit(self, context):
        info = self._get_subnet_info(context, context.current)
        if info:
            tenant_id, network_id, gateway_ip = info
            self.apic_manager.ensure_subnet_deleted_on_apic(
                tenant_id, network_id, gateway_ip)