# Copyright 2011-2012 OpenStack Foundation
# 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 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 CapacityWeigher
from cinder import test
from cinder.tests.scheduler import fakes
from cinder.volume import utils

CONF = cfg.CONF


class CapacityWeigherTestCase(test.TestCase):
    def setUp(self):
        super(CapacityWeigherTestCase, 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([CapacityWeigher],
                                                       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: free_capacity_gb=1024, free=1024*(1-0.1)
        # host2: free_capacity_gb=300, free=300*(1-0.1)
        # host3: free_capacity_gb=512, free=256
        # host4: free_capacity_gb=200, free=200*(1-0.05)
        # host5: free_capacity_gb=unknown free=-1

        # so, host1 should win:
        weighed_host = self._get_weighed_host(hostinfo_list)
        self.assertEqual(weighed_host.weight, 921.0)
        self.assertEqual(
            utils.extract_host(weighed_host.obj.host), 'host1')

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

        # host1: free_capacity_gb=1024, free=-1024*(1-0.1)
        # host2: free_capacity_gb=300, free=-300*(1-0.1)
        # host3: free_capacity_gb=512, free=-256
        # host4: free_capacity_gb=200, free=-200*(1-0.05)
        # host5: free_capacity_gb=unknown free=-float('inf')

        # so, host4 should win:
        weighed_host = self._get_weighed_host(hostinfo_list)
        self.assertEqual(weighed_host.weight, -190.0)
        self.assertEqual(
            utils.extract_host(weighed_host.obj.host), 'host4')

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

        # host1: free_capacity_gb=1024, free=1024*(1-0.1)*2
        # host2: free_capacity_gb=300, free=300*(1-0.1)*2
        # host3: free_capacity_gb=512, free=256*2
        # host4: free_capacity_gb=200, free=200*(1-0.05)*2
        # host5: free_capacity_gb=unknown free=-2

        # so, host1 should win:
        weighed_host = self._get_weighed_host(hostinfo_list)
        self.assertEqual(weighed_host.weight, 921.0 * 2)
        self.assertEqual(
            utils.extract_host(weighed_host.obj.host), 'host1')
