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

# Copyright 2011 OpenStack LLC.
# 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.

"""
Queues images for prefetching into the image cache
"""

import logging

import eventlet

from glance.common import config
from glance.common import context
from glance.common import exception
from glance.image_cache import ImageCache
from glance import registry


logger = logging.getLogger(__name__)


class Queuer(object):

    def __init__(self, options):
        self.options = options
        self.cache = ImageCache(options)
        registry.configure_registry_client(options)

    def queue_image(self, image_id):
        auth_tok = self.options.get('admin_token')
        ctx = context.RequestContext(is_admin=True, show_deleted=True,
                                     auth_tok=auth_tok)
        try:
            image_meta = registry.get_image_metadata(ctx, image_id)
            if image_meta['status'] != 'active':
                logger.warn(_("Image '%s' is not active. Not queueing."),
                            image_id)
                return False

        except exception.NotFound:
            logger.warn(_("No metadata found for image '%s'"), image_id)
            return False

        logger.debug(_("Queueing image '%s'"), image_id)
        self.cache.queue_image(image_id)
        return True

    def run(self, images):

        num_images = len(images)
        if num_images == 0:
            logger.debug(_("No images to queue!"))
            return True

        logger.debug(_("Received %d images to queue"), num_images)

        pool = eventlet.GreenPool(num_images)
        results = pool.imap(self.queue_image, images)
        successes = sum([1 for r in results if r is True])
        if successes != num_images:
            logger.error(_("Failed to successfully queue all "
                           "images in queue."))
            return False

        logger.info(_("Successfully queued all %d images"), num_images)
        return True


def app_factory(global_config, **local_conf):
    conf = global_config.copy()
    conf.update(local_conf)
    return Queuer(conf)
