#    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_concurrency import processutils
from oslo_log import log as logging
from stevedore import extension

import os_vif.exception
import os_vif.i18n
import os_vif.objects

_LE = os_vif.i18n._LE
_LI = os_vif.i18n._LI

_EXT_MANAGER = None
LOG = logging.getLogger('os_vif')


def initialize(reset=False, **config):
    """
    Loads all os_vif plugins and initializes them with a dictionary of
    configuration options. These configuration options are passed as-is
    to the individual VIF plugins that are loaded via stevedore.

    :param reset: Recreate and load the VIF plugin extensions.

    The following configuration options are currently known to be
    used by the VIF plugins, however this list may change and you
    should check the documentation of individual plugins for a complete
    list of configuration options that the plugin understands or uses.

    :param **config: Configuration option dictionary.

        `use_ipv6`: Default: False. For plugins that configure IPv6 iptables
                    rules or functionality, set this option to True if you want
                    to support IPv6.
        `disable_rootwrap`: Default: False. Set to True to force plugins to use
                    sudoers files instead of any `oslo.rootwrap` functionality.
        `use_rootwrap_daemon`: Default: False. Set to True to use the optional
                    `oslo.rootwrap` daemon for better performance of root-run
                    commands.
        `rootwrap_config`: Default: /etc/nova/rootwrap.conf. Path to the
                    rootwrap configuration file.
        `iptables_top_regex`: Default: ''. Override top filters in iptables
                    rules construction.
        `iptables_bottom_regex`: Default: ''. Override bottom filters in
                    iptables rules construction.
        `iptables_drop_action`: Default: DROP. Override the name of the drop
                    action in iptables rules.
        `forward_bridge_interface`: Default: ['all'].
        `network_device_mtu`: Default: 1500. Override the MTU of network
                    devices created by a VIF plugin.
    """
    global _EXT_MANAGER
    if reset or (_EXT_MANAGER is None):
        _EXT_MANAGER = extension.ExtensionManager(namespace='os_vif',
                                                  invoke_on_load=True,
                                                  invoke_args=config)
        os_vif.objects.register_all()


def plug(vif, instance):
    """
    Given a model of a VIF, perform operations to plug the VIF properly.

    :param vif: `os_vif.objects.VIF` object.
    :param instance: `nova.objects.Instance` object.
    :raises `exception.LibraryNotInitialized` if the user of the library
            did not call os_vif.initialize(**config) before trying to
            plug a VIF.
    :raises `exception.NoMatchingPlugin` if there is no plugin for the
            type of VIF supplied.
    :raises `exception.PlugException` if anything fails during unplug
            operations.
    """
    if _EXT_MANAGER is None:
        raise os_vif.exception.LibraryNotInitialized()

    plugin_name = vif.plugin
    try:
        plugin = _EXT_MANAGER[plugin_name]
    except KeyError:
        raise os_vif.exception.NoMatchingPlugin(plugin_name=plugin_name)

    try:
        LOG.debug("Plugging vif %s", vif)
        plugin.plug(vif, instance)
        LOG.info(_LI("Successfully plugged vif %s"), vif)
    except processutils.ProcessExecutionError as err:
        LOG.error(_LE("Failed to plug vif %(vif)s. Got error: %(err)s"),
                  vif=vif, err=err)
        raise os_vif.exception.PlugException(vif=vif, err=err)


def unplug(vif):
    """
    Given a model of a VIF, perform operations to unplug the VIF properly.

    :param vif: `os_vif.objects.VIF` object.
    :raises `exception.LibraryNotInitialized` if the user of the library
            did not call os_vif.initialize(**config) before trying to
            plug a VIF.
    :raises `exception.NoMatchingPlugin` if there is no plugin for the
            type of VIF supplied.
    :raises `exception.UnplugException` if anything fails during unplug
            operations.
    """
    if _EXT_MANAGER is None:
        raise os_vif.exception.LibraryNotInitialized()

    plugin_name = vif.plugin
    try:
        plugin = _EXT_MANAGER[plugin_name]
    except KeyError:
        raise os_vif.exception.NoMatchingPlugin(plugin_name=plugin_name)

    try:
        LOG.debug("Unplugging vif %s", vif)
        plugin.unplug(vif)
        LOG.info(_LI("Successfully unplugged vif %s"), vif)
    except processutils.ProcessExecutionError as err:
        LOG.error(_LE("Failed to unplug vif %(vif)s. Got error: %(err)s"),
                  vif=vif, err=err)
        raise os_vif.exception.UnplugException(vif=vif, err=err)