# Copyright 2011 Justin Santa Barbara
# 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.

"""The volumes snapshots api."""

import webob
from webob import exc

from cinder.api import common
from cinder.api.openstack import wsgi
from cinder.api import xmlutil
from cinder import exception
from cinder.i18n import _, _LI
from cinder.openstack.common import log as logging
from cinder.openstack.common import strutils
from cinder import utils
from cinder import volume


LOG = logging.getLogger(__name__)


def _translate_snapshot_detail_view(context, snapshot):
    """Maps keys for snapshots details view."""

    d = _translate_snapshot_summary_view(context, snapshot)

    # NOTE(gagupta): No additional data / lookups at the moment
    return d


def _translate_snapshot_summary_view(context, snapshot):
    """Maps keys for snapshots summary view."""
    d = {}

    d['id'] = snapshot['id']
    d['created_at'] = snapshot['created_at']
    d['display_name'] = snapshot['display_name']
    d['display_description'] = snapshot['display_description']
    d['volume_id'] = snapshot['volume_id']
    d['status'] = snapshot['status']
    d['size'] = snapshot['volume_size']

    if snapshot.get('snapshot_metadata'):
        metadata = snapshot.get('snapshot_metadata')
        d['metadata'] = dict((item['key'], item['value']) for item in metadata)
    # avoid circular ref when vol is a Volume instance
    elif snapshot.get('metadata') and isinstance(snapshot.get('metadata'),
                                                 dict):
        d['metadata'] = snapshot['metadata']
    else:
        d['metadata'] = {}
    return d


def make_snapshot(elem):
    elem.set('id')
    elem.set('status')
    elem.set('size')
    elem.set('created_at')
    elem.set('display_name')
    elem.set('display_description')
    elem.set('volume_id')
    elem.append(common.MetadataTemplate())


class SnapshotTemplate(xmlutil.TemplateBuilder):
    def construct(self):
        root = xmlutil.TemplateElement('snapshot', selector='snapshot')
        make_snapshot(root)
        return xmlutil.MasterTemplate(root, 1)


class SnapshotsTemplate(xmlutil.TemplateBuilder):
    def construct(self):
        root = xmlutil.TemplateElement('snapshots')
        elem = xmlutil.SubTemplateElement(root, 'snapshot',
                                          selector='snapshots')
        make_snapshot(elem)
        return xmlutil.MasterTemplate(root, 1)


class SnapshotsController(wsgi.Controller):
    """The Snapshots API controller for the OpenStack API."""

    def __init__(self, ext_mgr=None):
        self.volume_api = volume.API()
        self.ext_mgr = ext_mgr
        super(SnapshotsController, self).__init__()

    @wsgi.serializers(xml=SnapshotTemplate)
    def show(self, req, id):
        """Return data about the given snapshot."""
        context = req.environ['cinder.context']

        try:
            snapshot = self.volume_api.get_snapshot(context, id)
            req.cache_db_snapshot(snapshot)
        except exception.NotFound:
            raise exc.HTTPNotFound()

        return {'snapshot': _translate_snapshot_detail_view(context, snapshot)}

    def delete(self, req, id):
        """Delete a snapshot."""
        context = req.environ['cinder.context']

        LOG.info(_LI("Delete snapshot with id: %s"), id, context=context)

        try:
            snapshot = self.volume_api.get_snapshot(context, id)
            self.volume_api.delete_snapshot(context, snapshot)
        except exception.NotFound:
            raise exc.HTTPNotFound()
        return webob.Response(status_int=202)

    @wsgi.serializers(xml=SnapshotsTemplate)
    def index(self, req):
        """Returns a summary list of snapshots."""
        return self._items(req, entity_maker=_translate_snapshot_summary_view)

    @wsgi.serializers(xml=SnapshotsTemplate)
    def detail(self, req):
        """Returns a detailed list of snapshots."""
        return self._items(req, entity_maker=_translate_snapshot_detail_view)

    def _items(self, req, entity_maker):
        """Returns a list of snapshots, transformed through entity_maker."""
        context = req.environ['cinder.context']

        #pop out limit and offset , they are not search_opts
        search_opts = req.GET.copy()
        search_opts.pop('limit', None)
        search_opts.pop('offset', None)

        #filter out invalid option
        allowed_search_options = ('status', 'volume_id', 'display_name')
        utils.remove_invalid_filter_options(context, search_opts,
                                            allowed_search_options)

        snapshots = self.volume_api.get_all_snapshots(context,
                                                      search_opts=search_opts)
        limited_list = common.limited(snapshots, req)
        req.cache_db_snapshots(limited_list)
        res = [entity_maker(context, snapshot) for snapshot in limited_list]
        return {'snapshots': res}

    @wsgi.serializers(xml=SnapshotTemplate)
    def create(self, req, body):
        """Creates a new snapshot."""
        kwargs = {}
        context = req.environ['cinder.context']

        if not self.is_valid_body(body, 'snapshot'):
            raise exc.HTTPUnprocessableEntity()

        snapshot = body['snapshot']
        kwargs['metadata'] = snapshot.get('metadata', None)

        try:
            volume_id = snapshot['volume_id']
        except KeyError:
            msg = _("'volume_id' must be specified")
            raise exc.HTTPBadRequest(explanation=msg)

        try:
            volume = self.volume_api.get(context, volume_id)
        except exception.NotFound:
            raise exc.HTTPNotFound()

        force = snapshot.get('force', False)
        msg = _("Create snapshot from volume %s")
        LOG.info(msg, volume_id, context=context)

        if not utils.is_valid_boolstr(force):
            msg = _("Invalid value '%s' for force. ") % force
            raise exception.InvalidParameterValue(err=msg)

        if strutils.bool_from_string(force):
            new_snapshot = self.volume_api.create_snapshot_force(
                context,
                volume,
                snapshot.get('display_name'),
                snapshot.get('display_description'),
                **kwargs)
        else:
            new_snapshot = self.volume_api.create_snapshot(
                context,
                volume,
                snapshot.get('display_name'),
                snapshot.get('display_description'),
                **kwargs)
        req.cache_db_snapshot(new_snapshot)

        retval = _translate_snapshot_detail_view(context, new_snapshot)

        return {'snapshot': retval}

    @wsgi.serializers(xml=SnapshotTemplate)
    def update(self, req, id, body):
        """Update a snapshot."""
        context = req.environ['cinder.context']

        if not body:
            raise exc.HTTPUnprocessableEntity()

        if 'snapshot' not in body:
            raise exc.HTTPUnprocessableEntity()

        snapshot = body['snapshot']
        update_dict = {}

        valid_update_keys = (
            'display_name',
            'display_description',
        )

        for key in valid_update_keys:
            if key in snapshot:
                update_dict[key] = snapshot[key]

        try:
            snapshot = self.volume_api.get_snapshot(context, id)
            self.volume_api.update_snapshot(context, snapshot, update_dict)
        except exception.NotFound:
            raise exc.HTTPNotFound()

        snapshot.update(update_dict)
        req.cache_db_snapshot(snapshot)

        return {'snapshot': _translate_snapshot_detail_view(context, snapshot)}


def create_resource(ext_mgr):
    return wsgi.Resource(SnapshotsController(ext_mgr))
