# -*- encoding: utf-8 -*-
#
# Copyright © 2012 eNovance
#
# Author: Guillaume Pernot <gpernot@praksys.org>
#
# 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.
"""Common code for working with object stores
"""

from __future__ import absolute_import

import abc

from oslo.config import cfg
from swiftclient import client as swift

from ceilometer import counter
from ceilometer.openstack.common import log
from ceilometer.openstack.common import timeutils
from ceilometer import plugin


LOG = log.getLogger(__name__)

OPTS = [
    cfg.StrOpt('reseller_prefix',
               default='AUTH_',
               help="Swift reseller prefix. Must be on par with "
               "reseller_prefix in proxy-server.conf."),
]

cfg.CONF.register_opts(OPTS)


class _Base(plugin.PollsterBase):

    __metaclass__ = abc.ABCMeta

    @staticmethod
    @abc.abstractmethod
    def iter_accounts(ksclient):
        """Iterate over all accounts, yielding (tenant_id, stats) tuples."""

    def get_counters(self, manager):
        for tenant, account in self.iter_accounts(manager.keystone):
            yield counter.Counter(
                name='storage.objects',
                type=counter.TYPE_GAUGE,
                volume=int(account['x-account-object-count']),
                unit='object',
                user_id=None,
                project_id=tenant,
                resource_id=tenant,
                timestamp=timeutils.isotime(),
                resource_metadata=None,
            )
            yield counter.Counter(
                name='storage.objects.size',
                type=counter.TYPE_GAUGE,
                volume=int(account['x-account-bytes-used']),
                unit='B',
                user_id=None,
                project_id=tenant,
                resource_id=tenant,
                timestamp=timeutils.isotime(),
                resource_metadata=None,
            )
            yield counter.Counter(
                name='storage.objects.containers',
                type=counter.TYPE_GAUGE,
                volume=int(account['x-account-container-count']),
                unit='container',
                user_id=None,
                project_id=tenant,
                resource_id=tenant,
                timestamp=timeutils.isotime(),
                resource_metadata=None,
            )


class SwiftPollster(_Base):
    """Iterate over all accounts, using keystone.
    """

    @staticmethod
    def get_counter_names():
        return ['storage.objects',
                'storage.objects.size',
                'storage.objects.containers']

    @staticmethod
    def iter_accounts(ksclient):
        endpoint = ksclient.service_catalog.url_for(
            service_type='object-store',
            endpoint_type='adminURL')
        base_url = '%s/v1/%s' % (endpoint, cfg.CONF.reseller_prefix)
        for t in ksclient.tenants.list():
            yield (t.id, swift.head_account('%s%s' % (base_url, t.id),
                                            ksclient.auth_token))