# Copyright 2013 eBay Inc.
#
# 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.
"""
Tests For Allocated Capacity Weigher.
"""

import mock
from oslo_config import cfg

from cinder import context
from cinder.openstack.common.scheduler.weights import HostWeightHandler
from cinder.scheduler.weights.capacity import AllocatedCapacityWeigher as ACW
from cinder import test
from cinder.tests.scheduler import fakes
from cinder.volume import utils

CONF = cfg.CONF


class AllocatedCapacityWeigherTestCase(test.TestCase):
    def setUp(self):
        super(AllocatedCapacityWeigherTestCase, self).setUp()
        self.host_manager = fakes.FakeHostManager()
        self.weight_handler = HostWeightHandler('cinder.scheduler.weights')

    def _get_weighed_host(self, hosts, weight_properties=None):
        if weight_properties is None:
            weight_properties = {}
        return self.weight_handler.get_weighed_objects([ACW], hosts,
                                                       weight_properties)[0]

    @mock.patch('cinder.db.sqlalchemy.api.service_get_all_by_topic')
    def _get_all_hosts(self, _mock_service_get_all_by_topic, disabled=False):
        ctxt = context.get_admin_context()
        fakes.mock_host_manager_db_calls(_mock_service_get_all_by_topic,
                                         disabled=disabled)
        host_states = self.host_manager.get_all_host_states(ctxt)
        _mock_service_get_all_by_topic.assert_called_once_with(
            ctxt, CONF.volume_topic, disabled=disabled)
        return host_states

    def test_default_of_spreading_first(self):
        hostinfo_list = self._get_all_hosts()

        # host1: allocated_capacity_gb=0, weight=0
        # host2: allocated_capacity_gb=1748, weight=-1748
        # host3: allocated_capacity_gb=256, weight=-256
        # host4: allocated_capacity_gb=1848, weight=-1848

        # so, host1 should win:
        weighed_host = self._get_weighed_host(hostinfo_list)
        self.assertEqual(weighed_host.weight, 0)
        self.assertEqual(
            utils.extract_host(weighed_host.obj.host), 'host1')

    def test_capacity_weight_multiplier1(self):
        self.flags(allocated_capacity_weight_multiplier=1.0)
        hostinfo_list = self._get_all_hosts()

        # host1: allocated_capacity_gb=0, weight=0
        # host2: allocated_capacity_gb=1748, weight=1748
        # host3: allocated_capacity_gb=256, weight=256
        # host4: allocated_capacity_gb=1848, weight=1848

        # so, host4 should win:
        weighed_host = self._get_weighed_host(hostinfo_list)
        self.assertEqual(weighed_host.weight, 1848.0)
        self.assertEqual(
            utils.extract_host(weighed_host.obj.host), 'host4')

    def test_capacity_weight_multiplier2(self):
        self.flags(allocated_capacity_weight_multiplier=-2.0)
        hostinfo_list = self._get_all_hosts()

        # host1: allocated_capacity_gb=0, weight=0
        # host2: allocated_capacity_gb=1748, weight=-3496
        # host3: allocated_capacity_gb=256, weight=-512
        # host4: allocated_capacity_gb=1848, weight=-3696

        # so, host1 should win:
        weighed_host = self._get_weighed_host(hostinfo_list)
        self.assertEqual(weighed_host.weight, 0)
        self.assertEqual(
            utils.extract_host(weighed_host.obj.host), 'host1')