# Copyright 2012-2013 NEC Corporation.  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 neutron.openstack.common import excutils
from neutron.openstack.common import log as logging
from neutron.plugins.nec.common import config
from neutron.plugins.nec.common import exceptions as nexc
from neutron.plugins.nec.db import api as ndb
from neutron.plugins.nec.db import packetfilter as pf_db


LOG = logging.getLogger(__name__)


class PacketFilterMixin(pf_db.PacketFilterDbMixin):
    """Mixin class to add packet filter to NECPluginV2."""

    @property
    def packet_filter_enabled(self):
        if not hasattr(self, '_packet_filter_enabled'):
            self._packet_filter_enabled = (
                config.OFC.enable_packet_filter and
                self.ofc.driver.filter_supported())
        return self._packet_filter_enabled

    def remove_packet_filter_extension_if_disabled(self, aliases):
        if not self.packet_filter_enabled:
            LOG.debug(_('Disabled packet-filter extension.'))
            aliases.remove('packet-filter')

    def create_packet_filter(self, context, packet_filter):
        """Create a new packet_filter entry on DB, then try to activate it."""
        LOG.debug(_("create_packet_filter() called, packet_filter=%s ."),
                  packet_filter)

        if hasattr(self.ofc.driver, 'validate_filter_create'):
            pf = packet_filter['packet_filter']
            self.ofc.driver.validate_filter_create(context, pf)
        pf = super(PacketFilterMixin, self).create_packet_filter(
            context, packet_filter)

        return self.activate_packet_filter_if_ready(context, pf)

    def update_packet_filter(self, context, id, packet_filter):
        """Update packet_filter entry on DB, and recreate it if changed.

        If any rule of the packet_filter was changed, recreate it on OFC.
        """
        LOG.debug(_("update_packet_filter() called, "
                    "id=%(id)s packet_filter=%(packet_filter)s ."),
                  {'id': id, 'packet_filter': packet_filter})

        pf_data = packet_filter['packet_filter']
        if hasattr(self.ofc.driver, 'validate_filter_update'):
            self.ofc.driver.validate_filter_update(context, pf_data)

        # validate ownership
        pf_old = self.get_packet_filter(context, id)

        pf = super(PacketFilterMixin, self).update_packet_filter(
            context, id, packet_filter)

        def _packet_filter_changed(old_pf, new_pf):
            LOG.debug('old_pf=%(old_pf)s, new_pf=%(new_pf)s',
                      {'old_pf': old_pf, 'new_pf': new_pf})
            # When the status is ERROR, force sync to OFC.
            if old_pf['status'] == pf_db.PF_STATUS_ERROR:
                LOG.debug('update_packet_filter: Force filter update '
                          'because the previous status is ERROR.')
                return True
            for key in new_pf:
                if key in ('id', 'name', 'tenant_id', 'network_id',
                           'in_port', 'status'):
                    continue
                if old_pf[key] != new_pf[key]:
                    return True
            return False

        if _packet_filter_changed(pf_old, pf):
            if hasattr(self.ofc.driver, 'update_filter'):
                # admin_state is changed
                if pf_old['admin_state_up'] != pf['admin_state_up']:
                    LOG.debug('update_packet_filter: admin_state '
                              'is changed to %s', pf['admin_state_up'])
                    if pf['admin_state_up']:
                        self.activate_packet_filter_if_ready(context, pf)
                    else:
                        self.deactivate_packet_filter(context, pf)
                elif pf['admin_state_up']:
                    LOG.debug('update_packet_filter: admin_state is '
                              'unchanged (True)')
                    if self.ofc.exists_ofc_packet_filter(context, id):
                        pf = self._update_packet_filter(context, pf, pf_data)
                    else:
                        pf = self.activate_packet_filter_if_ready(context, pf)
                else:
                    LOG.debug('update_packet_filter: admin_state is unchanged '
                              '(False). No need to update OFC filter.')
            else:
                pf = self.deactivate_packet_filter(context, pf)
                pf = self.activate_packet_filter_if_ready(context, pf)

        return pf

    def _update_packet_filter(self, context, new_pf, pf_data):
        pf_id = new_pf['id']
        prev_status = new_pf['status']
        try:
            # If previous status is ERROR, try to sync all attributes.
            pf = new_pf if prev_status == pf_db.PF_STATUS_ERROR else pf_data
            self.ofc.update_ofc_packet_filter(context, pf_id, pf)
            new_status = pf_db.PF_STATUS_ACTIVE
            if new_status != prev_status:
                self._update_resource_status(context, "packet_filter",
                                             pf_id, new_status)
                new_pf['status'] = new_status
            return new_pf
        except Exception as exc:
            with excutils.save_and_reraise_exception():
                if (isinstance(exc, nexc.OFCException) or
                    isinstance(exc, nexc.OFCConsistencyBroken)):
                    LOG.error(_("Failed to create packet_filter id=%(id)s on "
                                "OFC: %(exc)s"),
                              {'id': pf_id, 'exc': exc})
                new_status = pf_db.PF_STATUS_ERROR
                if new_status != prev_status:
                    self._update_resource_status(context, "packet_filter",
                                                 pf_id, new_status)

    def delete_packet_filter(self, context, id):
        """Deactivate and delete packet_filter."""
        LOG.debug(_("delete_packet_filter() called, id=%s ."), id)

        # validate ownership
        pf = self.get_packet_filter(context, id)

        # deactivate_packet_filter() raises an exception
        # if an error occurs during processing.
        pf = self.deactivate_packet_filter(context, pf)

        super(PacketFilterMixin, self).delete_packet_filter(context, id)

    def activate_packet_filter_if_ready(self, context, packet_filter):
        """Activate packet_filter by creating filter on OFC if ready.

        Conditions to create packet_filter on OFC are:
            * packet_filter admin_state is UP
            * (if 'in_port' is specified) portinfo is available
        """
        LOG.debug(_("activate_packet_filter_if_ready() called, "
                    "packet_filter=%s."), packet_filter)

        pf_id = packet_filter['id']
        in_port_id = packet_filter.get('in_port')
        current = packet_filter['status']

        pf_status = current
        if not packet_filter['admin_state_up']:
            LOG.debug(_("activate_packet_filter_if_ready(): skip pf_id=%s, "
                        "packet_filter.admin_state_up is False."), pf_id)
        elif in_port_id and not ndb.get_portinfo(context.session, in_port_id):
            LOG.debug(_("activate_packet_filter_if_ready(): skip "
                        "pf_id=%s, no portinfo for the in_port."), pf_id)
        elif self.ofc.exists_ofc_packet_filter(context, packet_filter['id']):
            LOG.debug(_("_activate_packet_filter_if_ready(): skip, "
                        "ofc_packet_filter already exists."))
        else:
            LOG.debug(_("activate_packet_filter_if_ready(): create "
                        "packet_filter id=%s on OFC."), pf_id)
            try:
                self.ofc.create_ofc_packet_filter(context, pf_id,
                                                  packet_filter)
                pf_status = pf_db.PF_STATUS_ACTIVE
            except (nexc.OFCException, nexc.OFCMappingNotFound) as exc:
                LOG.error(_("Failed to create packet_filter id=%(id)s on "
                            "OFC: %(exc)s"), {'id': pf_id, 'exc': exc})
                pf_status = pf_db.PF_STATUS_ERROR

        if pf_status != current:
            self._update_resource_status(context, "packet_filter", pf_id,
                                         pf_status)
            packet_filter.update({'status': pf_status})

        return packet_filter

    def deactivate_packet_filter(self, context, packet_filter):
        """Deactivate packet_filter by deleting filter from OFC if exixts."""
        LOG.debug(_("deactivate_packet_filter_if_ready() called, "
                    "packet_filter=%s."), packet_filter)
        pf_id = packet_filter['id']

        if not self.ofc.exists_ofc_packet_filter(context, pf_id):
            LOG.debug(_("deactivate_packet_filter(): skip, "
                        "Not found OFC Mapping for packet_filter id=%s."),
                      pf_id)
            return packet_filter

        LOG.debug(_("deactivate_packet_filter(): "
                    "deleting packet_filter id=%s from OFC."), pf_id)
        try:
            self.ofc.delete_ofc_packet_filter(context, pf_id)
            self._update_resource_status_if_changed(
                context, "packet_filter", packet_filter, pf_db.PF_STATUS_DOWN)
            return packet_filter
        except (nexc.OFCException, nexc.OFCMappingNotFound) as exc:
            with excutils.save_and_reraise_exception():
                LOG.error(_("Failed to delete packet_filter id=%(id)s "
                            "from OFC: %(exc)s"),
                          {'id': pf_id, 'exc': str(exc)})
                self._update_resource_status_if_changed(
                    context, "packet_filter", packet_filter,
                    pf_db.PF_STATUS_ERROR)

    def activate_packet_filters_by_port(self, context, port_id):
        if not self.packet_filter_enabled:
            return

        filters = {'in_port': [port_id], 'admin_state_up': [True],
                   'status': [pf_db.PF_STATUS_DOWN]}
        pfs = self.get_packet_filters(context, filters=filters)
        for pf in pfs:
            self.activate_packet_filter_if_ready(context, pf)

    def deactivate_packet_filters_by_port(self, context, port_id,
                                          raise_exc=True):
        if not self.packet_filter_enabled:
            return

        filters = {'in_port': [port_id], 'status': [pf_db.PF_STATUS_ACTIVE]}
        pfs = self.get_packet_filters(context, filters=filters)
        error = False
        for pf in pfs:
            try:
                self.deactivate_packet_filter(context, pf)
            except (nexc.OFCException, nexc.OFCMappingNotFound):
                error = True
        if raise_exc and error:
            raise nexc.OFCException(_('Error occurred while disabling packet '
                                      'filter(s) for port %s'), port_id)

    def get_packet_filters_for_port(self, context, port):
        if self.packet_filter_enabled:
            return super(PacketFilterMixin,
                         self).get_packet_filters_for_port(context, port)
