# vim: tabstop=4 shiftwidth=4 softtabstop=4

#Copyright 2013 Cloudbase Solutions SRL
#Copyright 2013 Pedro Navarro Perez
#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: Pedro Navarro Perez
# @author: Alessandro Pilotti, Cloudbase Solutions Srl

import eventlet
import platform
import re
import time

from oslo.config import cfg

from neutron.agent.common import config
from neutron.agent import rpc as agent_rpc
from neutron.common import config as logging_config
from neutron.common import constants as n_const
from neutron.common import topics
from neutron import context
from neutron.openstack.common import log as logging
from neutron.openstack.common import loopingcall
from neutron.openstack.common.rpc import dispatcher
from neutron.plugins.hyperv.agent import utils
from neutron.plugins.hyperv.agent import utilsfactory
from neutron.plugins.hyperv.common import constants

LOG = logging.getLogger(__name__)

agent_opts = [
    cfg.ListOpt(
        'physical_network_vswitch_mappings',
        default=[],
        help=_('List of <physical_network>:<vswitch> '
        'where the physical networks can be expressed with '
        'wildcards, e.g.: ."*:external"')),
    cfg.StrOpt(
        'local_network_vswitch',
        default='private',
        help=_('Private vswitch name used for local networks')),
    cfg.IntOpt('polling_interval', default=2,
               help=_("The number of seconds the agent will wait between "
                      "polling for local device changes.")),
    cfg.BoolOpt('enable_metrics_collection',
                default=False,
                help=_('Enables metrics collections for switch ports by using '
                       'Hyper-V\'s metric APIs. Collected data can by '
                       'retrieved by other apps and services, e.g.: '
                       'Ceilometer. Requires Hyper-V / Windows Server 2012 '
                       'and above'))
]


CONF = cfg.CONF
CONF.register_opts(agent_opts, "AGENT")
config.register_agent_state_opts_helper(cfg.CONF)


class HyperVNeutronAgent(object):
    # Set RPC API version to 1.0 by default.
    RPC_API_VERSION = '1.0'

    def __init__(self):
        self._utils = utilsfactory.get_hypervutils()
        self._polling_interval = CONF.AGENT.polling_interval
        self._load_physical_network_mappings()
        self._network_vswitch_map = {}
        self._set_agent_state()
        self._setup_rpc()

    def _set_agent_state(self):
        self.agent_state = {
            'binary': 'neutron-hyperv-agent',
            'host': cfg.CONF.host,
            'topic': n_const.L2_AGENT_TOPIC,
            'configurations': {'vswitch_mappings':
                               self._physical_network_mappings},
            'agent_type': n_const.AGENT_TYPE_HYPERV,
            'start_flag': True}

    def _report_state(self):
        try:
            self.state_rpc.report_state(self.context,
                                        self.agent_state)
            self.agent_state.pop('start_flag', None)
        except Exception as ex:
            LOG.exception(_("Failed reporting state! %s"), ex)

    def _setup_rpc(self):
        self.agent_id = 'hyperv_%s' % platform.node()
        self.topic = topics.AGENT
        self.plugin_rpc = agent_rpc.PluginApi(topics.PLUGIN)

        self.state_rpc = agent_rpc.PluginReportStateAPI(topics.PLUGIN)

        # RPC network init
        self.context = context.get_admin_context_without_session()
        # Handle updates from service
        self.dispatcher = self._create_rpc_dispatcher()
        # Define the listening consumers for the agent
        consumers = [[topics.PORT, topics.UPDATE],
                     [topics.NETWORK, topics.DELETE],
                     [topics.PORT, topics.DELETE],
                     [constants.TUNNEL, topics.UPDATE]]
        self.connection = agent_rpc.create_consumers(self.dispatcher,
                                                     self.topic,
                                                     consumers)
        report_interval = CONF.AGENT.report_interval
        if report_interval:
            heartbeat = loopingcall.LoopingCall(self._report_state)
            heartbeat.start(interval=report_interval)

    def _load_physical_network_mappings(self):
        self._physical_network_mappings = {}
        for mapping in CONF.AGENT.physical_network_vswitch_mappings:
            parts = mapping.split(':')
            if len(parts) != 2:
                LOG.debug(_('Invalid physical network mapping: %s'), mapping)
            else:
                pattern = re.escape(parts[0].strip()).replace('\\*', '.*')
                vswitch = parts[1].strip()
                self._physical_network_mappings[pattern] = vswitch

    def _get_vswitch_for_physical_network(self, phys_network_name):
        for pattern in self._physical_network_mappings:
            if phys_network_name is None:
                phys_network_name = ''
            if re.match(pattern, phys_network_name):
                return self._physical_network_mappings[pattern]
        # Not found in the mappings, the vswitch has the same name
        return phys_network_name

    def _get_network_vswitch_map_by_port_id(self, port_id):
        for network_id, map in self._network_vswitch_map.iteritems():
            if port_id in map['ports']:
                return (network_id, map)

    def network_delete(self, context, network_id=None):
        LOG.debug(_("network_delete received. "
                    "Deleting network %s"), network_id)
        # The network may not be defined on this agent
        if network_id in self._network_vswitch_map:
            self._reclaim_local_network(network_id)
        else:
            LOG.debug(_("Network %s not defined on agent."), network_id)

    def port_delete(self, context, port_id=None):
        LOG.debug(_("port_delete received"))
        self._port_unbound(port_id)

    def port_update(self, context, port=None, network_type=None,
                    segmentation_id=None, physical_network=None):
        LOG.debug(_("port_update received"))
        self._treat_vif_port(
            port['id'], port['network_id'],
            network_type, physical_network,
            segmentation_id, port['admin_state_up'])

    def _create_rpc_dispatcher(self):
        return dispatcher.RpcDispatcher([self])

    def _get_vswitch_name(self, network_type, physical_network):
        if network_type != constants.TYPE_LOCAL:
            vswitch_name = self._get_vswitch_for_physical_network(
                physical_network)
        else:
            vswitch_name = CONF.AGENT.local_network_vswitch
        return vswitch_name

    def _provision_network(self, port_id,
                           net_uuid, network_type,
                           physical_network,
                           segmentation_id):
        LOG.info(_("Provisioning network %s"), net_uuid)

        vswitch_name = self._get_vswitch_name(network_type, physical_network)

        if network_type in [constants.TYPE_VLAN, constants.TYPE_FLAT]:
            #Nothing to do
            pass
        elif network_type == constants.TYPE_LOCAL:
            #TODO(alexpilotti): Check that the switch type is private
            #or create it if not existing
            pass
        else:
            raise utils.HyperVException(
                msg=(_("Cannot provision unknown network type %(network_type)s"
                       " for network %(net_uuid)s") %
                     dict(network_type=network_type, net_uuid=net_uuid)))

        map = {
            'network_type': network_type,
            'vswitch_name': vswitch_name,
            'ports': [],
            'vlan_id': segmentation_id}
        self._network_vswitch_map[net_uuid] = map

    def _reclaim_local_network(self, net_uuid):
        LOG.info(_("Reclaiming local network %s"), net_uuid)
        del self._network_vswitch_map[net_uuid]

    def _port_bound(self, port_id,
                    net_uuid,
                    network_type,
                    physical_network,
                    segmentation_id):
        LOG.debug(_("Binding port %s"), port_id)

        if net_uuid not in self._network_vswitch_map:
            self._provision_network(
                port_id, net_uuid, network_type,
                physical_network, segmentation_id)

        map = self._network_vswitch_map[net_uuid]
        map['ports'].append(port_id)

        self._utils.connect_vnic_to_vswitch(map['vswitch_name'], port_id)

        if network_type == constants.TYPE_VLAN:
            LOG.info(_('Binding VLAN ID %(segmentation_id)s '
                       'to switch port %(port_id)s'),
                     dict(segmentation_id=segmentation_id, port_id=port_id))
            self._utils.set_vswitch_port_vlan_id(
                segmentation_id,
                port_id)
        elif network_type == constants.TYPE_FLAT:
            #Nothing to do
            pass
        elif network_type == constants.TYPE_LOCAL:
            #Nothing to do
            pass
        else:
            LOG.error(_('Unsupported network type %s'), network_type)

        if CONF.AGENT.enable_metrics_collection:
            self._utils.enable_port_metrics_collection(port_id)

    def _port_unbound(self, port_id):
        (net_uuid, map) = self._get_network_vswitch_map_by_port_id(port_id)
        if net_uuid not in self._network_vswitch_map:
            LOG.info(_('Network %s is not avalailable on this agent'),
                     net_uuid)
            return

        LOG.debug(_("Unbinding port %s"), port_id)
        self._utils.disconnect_switch_port(map['vswitch_name'], port_id, True)

        if not map['ports']:
            self._reclaim_local_network(net_uuid)

    def _update_ports(self, registered_ports):
        ports = self._utils.get_vnic_ids()
        if ports == registered_ports:
            return
        added = ports - registered_ports
        removed = registered_ports - ports
        return {'current': ports,
                'added': added,
                'removed': removed}

    def _treat_vif_port(self, port_id, network_id, network_type,
                        physical_network, segmentation_id,
                        admin_state_up):
        if self._utils.vnic_port_exists(port_id):
            if admin_state_up:
                self._port_bound(port_id, network_id, network_type,
                                 physical_network, segmentation_id)
            else:
                self._port_unbound(port_id)
        else:
            LOG.debug(_("No port %s defined on agent."), port_id)

    def _treat_devices_added(self, devices):
        resync = False
        for device in devices:
            LOG.info(_("Adding port %s"), device)
            try:
                device_details = self.plugin_rpc.get_device_details(
                    self.context,
                    device,
                    self.agent_id)
            except Exception as e:
                LOG.debug(
                    _("Unable to get port details for "
                      "device %(device)s: %(e)s"),
                    {'device': device, 'e': e})
                resync = True
                continue
            if 'port_id' in device_details:
                LOG.info(
                    _("Port %(device)s updated. Details: %(device_details)s"),
                    {'device': device, 'device_details': device_details})
                self._treat_vif_port(
                    device_details['port_id'],
                    device_details['network_id'],
                    device_details['network_type'],
                    device_details['physical_network'],
                    device_details['segmentation_id'],
                    device_details['admin_state_up'])
        return resync

    def _treat_devices_removed(self, devices):
        resync = False
        for device in devices:
            LOG.info(_("Removing port %s"), device)
            try:
                self.plugin_rpc.update_device_down(self.context,
                                                   device,
                                                   self.agent_id)
            except Exception as e:
                LOG.debug(
                    _("Removing port failed for device %(device)s: %(e)s"),
                    dict(device=device, e=e))
                resync = True
                continue
            self._port_unbound(device)
        return resync

    def _process_network_ports(self, port_info):
        resync_a = False
        resync_b = False
        if 'added' in port_info:
            resync_a = self._treat_devices_added(port_info['added'])
        if 'removed' in port_info:
            resync_b = self._treat_devices_removed(port_info['removed'])
        # If one of the above operations fails => resync with plugin
        return (resync_a | resync_b)

    def daemon_loop(self):
        sync = True
        ports = set()

        while True:
            try:
                start = time.time()
                if sync:
                    LOG.info(_("Agent out of sync with plugin!"))
                    ports.clear()
                    sync = False

                port_info = self._update_ports(ports)

                # notify plugin about port deltas
                if port_info:
                    LOG.debug(_("Agent loop has new devices!"))
                    # If treat devices fails - must resync with plugin
                    sync = self._process_network_ports(port_info)
                    ports = port_info['current']
            except Exception as e:
                LOG.exception(_("Error in agent event loop: %s"), e)
                sync = True

            # sleep till end of polling interval
            elapsed = (time.time() - start)
            if (elapsed < self._polling_interval):
                time.sleep(self._polling_interval - elapsed)
            else:
                LOG.debug(_("Loop iteration exceeded interval "
                            "(%(polling_interval)s vs. %(elapsed)s)"),
                          {'polling_interval': self._polling_interval,
                           'elapsed': elapsed})


def main():
    eventlet.monkey_patch()
    cfg.CONF(project='neutron')
    logging_config.setup_logging(cfg.CONF)

    plugin = HyperVNeutronAgent()

    # Start everything.
    LOG.info(_("Agent initialized successfully, now running... "))
    plugin.daemon_loop()
