#   Copyright 2011 OpenStack, LLC.
#
#   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.

"""The rescue mode extension."""

import webob
from webob import exc

from nova.api.openstack import common
from nova.api.openstack import extensions as exts
from nova.api.openstack import wsgi
from nova import compute
from nova import exception
from nova.openstack.common import cfg
from nova.openstack.common import log as logging
from nova import utils


CONF = cfg.CONF
CONF.import_opt('password_length', 'nova.config')
LOG = logging.getLogger(__name__)
authorize = exts.extension_authorizer('compute', 'rescue')


class RescueController(wsgi.Controller):
    def __init__(self, *args, **kwargs):
        super(RescueController, self).__init__(*args, **kwargs)
        self.compute_api = compute.API()

    def _get_instance(self, context, instance_id):
        try:
            return self.compute_api.get(context, instance_id)
        except exception.InstanceNotFound:
            msg = _("Server not found")
            raise exc.HTTPNotFound(msg)

    @wsgi.action('rescue')
    @exts.wrap_errors
    def _rescue(self, req, id, body):
        """Rescue an instance."""
        context = req.environ["nova.context"]
        authorize(context)

        if body['rescue'] and 'adminPass' in body['rescue']:
            password = body['rescue']['adminPass']
        else:
            password = utils.generate_password(CONF.password_length)

        instance = self._get_instance(context, id)
        try:
            self.compute_api.rescue(context, instance,
                                    rescue_password=password)
        except exception.InstanceInvalidState as state_error:
            common.raise_http_conflict_for_instance_invalid_state(state_error,
                                                                  'rescue')
        return {'adminPass': password}

    @wsgi.action('unrescue')
    @exts.wrap_errors
    def _unrescue(self, req, id, body):
        """Unrescue an instance."""
        context = req.environ["nova.context"]
        authorize(context)
        instance = self._get_instance(context, id)
        try:
            self.compute_api.unrescue(context, instance)
        except exception.InstanceInvalidState as state_error:
            common.raise_http_conflict_for_instance_invalid_state(state_error,
                                                                  'unrescue')
        return webob.Response(status_int=202)


class Rescue(exts.ExtensionDescriptor):
    """Instance rescue mode"""

    name = "Rescue"
    alias = "os-rescue"
    namespace = "http://docs.openstack.org/compute/ext/rescue/api/v1.1"
    updated = "2011-08-18T00:00:00+00:00"

    def get_controller_extensions(self):
        controller = RescueController()
        extension = exts.ControllerExtension(self, 'servers', controller)
        return [extension]
