# Copyright 2013-2014 DataStax, Inc.
#
# 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.

import struct
import time
from cassandra import ConsistencyLevel, Unavailable
from cassandra.cluster import Cluster, NoHostAvailable
from cassandra.concurrent import execute_concurrent_with_args
from cassandra.policies import (RoundRobinPolicy, DCAwareRoundRobinPolicy,
                                TokenAwarePolicy, WhiteListRoundRobinPolicy)
from cassandra.query import SimpleStatement

from tests.integration import use_multidc, use_singledc, PROTOCOL_VERSION
from tests.integration.long.utils import (wait_for_up, create_schema,
                                          CoordinatorStats, force_stop,
                                          wait_for_down, decommission, start,
                                          bootstrap, stop, IP_FORMAT)

try:
    import unittest2 as unittest
except ImportError:
    import unittest  # noqa


class LoadBalancingPolicyTests(unittest.TestCase):
    def setUp(self):
        self.coordinator_stats = CoordinatorStats()
        self.prepared = None

    @classmethod
    def tearDownClass(cls):
        use_singledc()

    def _insert(self, session, keyspace, count=12,
                consistency_level=ConsistencyLevel.ONE):
        session.execute('USE %s' % keyspace)
        ss = SimpleStatement('INSERT INTO cf(k, i) VALUES (0, 0)',
                             consistency_level=consistency_level)
        execute_concurrent_with_args(session, ss, [None] * count)

    def _query(self, session, keyspace, count=12,
               consistency_level=ConsistencyLevel.ONE, use_prepared=False):
        if use_prepared:
            query_string = 'SELECT * FROM %s.cf WHERE k = ?' % keyspace
            if not self.prepared or self.prepared.query_string != query_string:
                self.prepared = session.prepare(query_string)

            for i in range(count):
                self.coordinator_stats.add_coordinator(session.execute_async(self.prepared.bind((0,))))
        else:
            routing_key = struct.pack('>i', 0)
            for i in range(count):
                ss = SimpleStatement('SELECT * FROM %s.cf WHERE k = 0' % keyspace,
                                     consistency_level=consistency_level,
                                     routing_key=routing_key)
                self.coordinator_stats.add_coordinator(session.execute_async(ss))

    def test_roundrobin(self):
        use_singledc()
        keyspace = 'test_roundrobin'
        cluster = Cluster(
            load_balancing_policy=RoundRobinPolicy(),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3)

        create_schema(session, keyspace, replication_factor=3)
        self._insert(session, keyspace)
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 4)
        self.coordinator_stats.assert_query_count_equals(self, 2, 4)
        self.coordinator_stats.assert_query_count_equals(self, 3, 4)

        force_stop(3)
        wait_for_down(cluster, 3)

        self.coordinator_stats.reset_counts()
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 6)
        self.coordinator_stats.assert_query_count_equals(self, 2, 6)
        self.coordinator_stats.assert_query_count_equals(self, 3, 0)

        decommission(1)
        start(3)
        wait_for_down(cluster, 1)
        wait_for_up(cluster, 3)

        self.coordinator_stats.reset_counts()
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 6)
        self.coordinator_stats.assert_query_count_equals(self, 3, 6)

    def test_roundrobin_two_dcs(self):
        use_multidc([2, 2])
        keyspace = 'test_roundrobin_two_dcs'
        cluster = Cluster(
            load_balancing_policy=RoundRobinPolicy(),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3, wait=False)
        wait_for_up(cluster, 4)

        create_schema(session, keyspace, replication_strategy=[2, 2])
        self._insert(session, keyspace)
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 3)
        self.coordinator_stats.assert_query_count_equals(self, 2, 3)
        self.coordinator_stats.assert_query_count_equals(self, 3, 3)
        self.coordinator_stats.assert_query_count_equals(self, 4, 3)

        force_stop(1)
        bootstrap(5, 'dc3')

        # reset control connection
        self._insert(session, keyspace, count=1000)

        wait_for_up(cluster, 5)

        self.coordinator_stats.reset_counts()
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 3)
        self.coordinator_stats.assert_query_count_equals(self, 3, 3)
        self.coordinator_stats.assert_query_count_equals(self, 4, 3)
        self.coordinator_stats.assert_query_count_equals(self, 5, 3)

    def test_roundrobin_two_dcs_2(self):
        use_multidc([2, 2])
        keyspace = 'test_roundrobin_two_dcs_2'
        cluster = Cluster(
            load_balancing_policy=RoundRobinPolicy(),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3, wait=False)
        wait_for_up(cluster, 4)

        create_schema(session, keyspace, replication_strategy=[2, 2])
        self._insert(session, keyspace)
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 3)
        self.coordinator_stats.assert_query_count_equals(self, 2, 3)
        self.coordinator_stats.assert_query_count_equals(self, 3, 3)
        self.coordinator_stats.assert_query_count_equals(self, 4, 3)

        force_stop(1)
        bootstrap(5, 'dc1')

        # reset control connection
        self._insert(session, keyspace, count=1000)

        wait_for_up(cluster, 5)

        self.coordinator_stats.reset_counts()
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 3)
        self.coordinator_stats.assert_query_count_equals(self, 3, 3)
        self.coordinator_stats.assert_query_count_equals(self, 4, 3)
        self.coordinator_stats.assert_query_count_equals(self, 5, 3)

    def test_dc_aware_roundrobin_two_dcs(self):
        use_multidc([3, 2])
        keyspace = 'test_dc_aware_roundrobin_two_dcs'
        cluster = Cluster(
            load_balancing_policy=DCAwareRoundRobinPolicy('dc1'),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3, wait=False)
        wait_for_up(cluster, 4, wait=False)
        wait_for_up(cluster, 5)

        create_schema(session, keyspace, replication_strategy=[2, 2])
        self._insert(session, keyspace)
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 4)
        self.coordinator_stats.assert_query_count_equals(self, 2, 4)
        self.coordinator_stats.assert_query_count_equals(self, 3, 4)
        self.coordinator_stats.assert_query_count_equals(self, 4, 0)
        self.coordinator_stats.assert_query_count_equals(self, 5, 0)

    def test_dc_aware_roundrobin_two_dcs_2(self):
        use_multidc([3, 2])
        keyspace = 'test_dc_aware_roundrobin_two_dcs_2'
        cluster = Cluster(
            load_balancing_policy=DCAwareRoundRobinPolicy('dc2'),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3, wait=False)
        wait_for_up(cluster, 4, wait=False)
        wait_for_up(cluster, 5)

        create_schema(session, keyspace, replication_strategy=[2, 2])
        self._insert(session, keyspace)
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 0)
        self.coordinator_stats.assert_query_count_equals(self, 3, 0)
        self.coordinator_stats.assert_query_count_equals(self, 4, 6)
        self.coordinator_stats.assert_query_count_equals(self, 5, 6)

    def test_dc_aware_roundrobin_one_remote_host(self):
        use_multidc([2, 2])
        keyspace = 'test_dc_aware_roundrobin_one_remote_host'
        cluster = Cluster(
            load_balancing_policy=DCAwareRoundRobinPolicy('dc2', used_hosts_per_remote_dc=1),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3, wait=False)
        wait_for_up(cluster, 4)

        create_schema(session, keyspace, replication_strategy=[2, 2])
        self._insert(session, keyspace)
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 0)
        self.coordinator_stats.assert_query_count_equals(self, 3, 6)
        self.coordinator_stats.assert_query_count_equals(self, 4, 6)

        self.coordinator_stats.reset_counts()
        bootstrap(5, 'dc1')
        wait_for_up(cluster, 5)

        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 0)
        self.coordinator_stats.assert_query_count_equals(self, 3, 6)
        self.coordinator_stats.assert_query_count_equals(self, 4, 6)
        self.coordinator_stats.assert_query_count_equals(self, 5, 0)

        self.coordinator_stats.reset_counts()
        decommission(3)
        decommission(4)
        wait_for_down(cluster, 3, wait=True)
        wait_for_down(cluster, 4, wait=True)

        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 3, 0)
        self.coordinator_stats.assert_query_count_equals(self, 4, 0)
        responses = set()
        for node in [1, 2, 5]:
            responses.add(self.coordinator_stats.get_query_count(node))
        self.assertEqual(set([0, 0, 12]), responses)

        self.coordinator_stats.reset_counts()
        decommission(5)
        wait_for_down(cluster, 5, wait=True)

        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 3, 0)
        self.coordinator_stats.assert_query_count_equals(self, 4, 0)
        self.coordinator_stats.assert_query_count_equals(self, 5, 0)
        responses = set()
        for node in [1, 2]:
            responses.add(self.coordinator_stats.get_query_count(node))
        self.assertEqual(set([0, 12]), responses)

        self.coordinator_stats.reset_counts()
        decommission(1)
        wait_for_down(cluster, 1, wait=True)

        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 12)
        self.coordinator_stats.assert_query_count_equals(self, 3, 0)
        self.coordinator_stats.assert_query_count_equals(self, 4, 0)
        self.coordinator_stats.assert_query_count_equals(self, 5, 0)

        self.coordinator_stats.reset_counts()
        force_stop(2)

        try:
            self._query(session, keyspace)
            self.fail()
        except NoHostAvailable:
            pass

    def test_token_aware(self):
        keyspace = 'test_token_aware'
        self.token_aware(keyspace)

    def test_token_aware_prepared(self):
        keyspace = 'test_token_aware_prepared'
        self.token_aware(keyspace, True)

    def token_aware(self, keyspace, use_prepared=False):
        use_singledc()
        cluster = Cluster(
            load_balancing_policy=TokenAwarePolicy(RoundRobinPolicy()),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3)

        create_schema(session, keyspace, replication_factor=1)
        self._insert(session, keyspace)
        self._query(session, keyspace, use_prepared=use_prepared)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 12)
        self.coordinator_stats.assert_query_count_equals(self, 3, 0)

        self.coordinator_stats.reset_counts()
        self._query(session, keyspace, use_prepared=use_prepared)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 12)
        self.coordinator_stats.assert_query_count_equals(self, 3, 0)

        self.coordinator_stats.reset_counts()
        force_stop(2)
        wait_for_down(cluster, 2, wait=True)

        try:
            self._query(session, keyspace, use_prepared=use_prepared)
            self.fail()
        except Unavailable as e:
            self.assertEqual(e.consistency, 1)
            self.assertEqual(e.required_replicas, 1)
            self.assertEqual(e.alive_replicas, 0)

        self.coordinator_stats.reset_counts()
        start(2)
        wait_for_up(cluster, 2, wait=True)

        self._query(session, keyspace, use_prepared=use_prepared)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 12)
        self.coordinator_stats.assert_query_count_equals(self, 3, 0)

        self.coordinator_stats.reset_counts()
        stop(2)
        wait_for_down(cluster, 2, wait=True)

        try:
            self._query(session, keyspace, use_prepared=use_prepared)
            self.fail()
        except Unavailable:
            pass

        self.coordinator_stats.reset_counts()
        start(2)
        wait_for_up(cluster, 2, wait=True)
        decommission(2)
        wait_for_down(cluster, 2, wait=True)

        self._query(session, keyspace, use_prepared=use_prepared)

        results = set([
            self.coordinator_stats.get_query_count(1),
            self.coordinator_stats.get_query_count(3)
        ])
        self.assertEqual(results, set([0, 12]))
        self.coordinator_stats.assert_query_count_equals(self, 2, 0)

    def test_token_aware_composite_key(self):
        use_singledc()
        keyspace = 'test_token_aware_composite_key'
        table = 'composite'
        cluster = Cluster(
            load_balancing_policy=TokenAwarePolicy(RoundRobinPolicy()),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3)

        create_schema(session, keyspace, replication_factor=2)
        session.execute('CREATE TABLE %s ('
                        'k1 int, '
                        'k2 int, '
                        'i int, '
                        'PRIMARY KEY ((k1, k2)))' % table)

        prepared = session.prepare('INSERT INTO %s '
                                   '(k1, k2, i) '
                                   'VALUES '
                                   '(?, ?, ?)' % table)
        session.execute(prepared.bind((1, 2, 3)))

        results = session.execute('SELECT * FROM %s WHERE k1 = 1 AND k2 = 2' % table)
        self.assertTrue(len(results) == 1)
        self.assertTrue(results[0].i)

    def test_token_aware_with_rf_2(self, use_prepared=False):
        use_singledc()
        keyspace = 'test_token_aware_with_rf_2'
        cluster = Cluster(
            load_balancing_policy=TokenAwarePolicy(RoundRobinPolicy()),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3)

        create_schema(session, keyspace, replication_factor=2)
        self._insert(session, keyspace)
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 12)
        self.coordinator_stats.assert_query_count_equals(self, 3, 0)

        self.coordinator_stats.reset_counts()
        stop(2)
        wait_for_down(cluster, 2, wait=True)

        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 0)
        self.coordinator_stats.assert_query_count_equals(self, 3, 12)

    def test_white_list(self):
        use_singledc()
        keyspace = 'test_white_list'

        cluster = Cluster(('127.0.0.2',),
            load_balancing_policy=WhiteListRoundRobinPolicy((IP_FORMAT % 2,)),
            protocol_version=PROTOCOL_VERSION)
        session = cluster.connect()
        wait_for_up(cluster, 1, wait=False)
        wait_for_up(cluster, 2, wait=False)
        wait_for_up(cluster, 3)

        create_schema(session, keyspace)
        self._insert(session, keyspace)
        self._query(session, keyspace)

        self.coordinator_stats.assert_query_count_equals(self, 1, 0)
        self.coordinator_stats.assert_query_count_equals(self, 2, 12)
        self.coordinator_stats.assert_query_count_equals(self, 3, 0)

        # white list policy should not allow reconnecting to ignored hosts
        force_stop(3)
        wait_for_down(cluster, 3)
        self.assertFalse(cluster.metadata._hosts[IP_FORMAT % 3].is_currently_reconnecting())

        self.coordinator_stats.reset_counts()
        force_stop(2)
        time.sleep(10)

        try:
            self._query(session, keyspace)
            self.fail()
        except NoHostAvailable:
            pass