import time
import pytest
import os

from helpers.cluster import ClickHouseCluster
from helpers.client import QueryRuntimeException
from helpers.test_tools import assert_eq_with_retry


cluster = ClickHouseCluster(__file__, zookeeper_config_path='configs/zookeeper.xml')
node = cluster.add_instance('node', with_zookeeper=True)


@pytest.fixture(scope="module")
def start_cluster():
    try:
        cluster.start()
        node.query(
    '''
        CREATE TABLE test_table(date Date, id UInt32)
        ENGINE = ReplicatedMergeTree('/clickhouse/tables/shard1/test/test_table', '1')
        PARTITION BY toYYYYMM(date)
        ORDER BY id
    ''')

        yield cluster
    finally:
        cluster.shutdown()

def test_reload_zookeeper(start_cluster):

    def wait_zookeeper_node_to_start(zk_nodes, timeout=60):
        start = time.time()
        while time.time() - start < timeout:
            try:
                for instance in zk_nodes:
                    conn = start_cluster.get_kazoo_client(instance)
                    conn.get_children('/')
                print("All instances of ZooKeeper started")
                return
            except Exception as ex:
                print(("Can't connect to ZooKeeper " + str(ex)))
                time.sleep(0.5)

    node.query("INSERT INTO test_table(date, id) select today(), number FROM numbers(1000)")

    ## remove zoo2, zoo3 from configs
    new_config = """
<yandex>
    <zookeeper>
        <node index="1">
            <host>zoo1</host>
            <port>2181</port>
        </node>
        <session_timeout_ms>2000</session_timeout_ms>
    </zookeeper>
</yandex >
"""
    node.replace_config("/etc/clickhouse-server/conf.d/zookeeper.xml", new_config)
    node.query("SYSTEM RELOAD CONFIG")
    ## config reloads, but can still work
    assert_eq_with_retry(node, "SELECT COUNT() FROM test_table", '1000', retry_count=120, sleep_time=0.5)

    ## stop all zookeepers, table will be readonly
    cluster.stop_zookeeper_nodes(["zoo1", "zoo2", "zoo3"])
    node.query("SELECT COUNT() FROM test_table")
    with pytest.raises(QueryRuntimeException):
        node.query("SELECT COUNT() FROM test_table", settings={"select_sequential_consistency" : 1})

    ## start zoo2, zoo3, table will be readonly too, because it only connect to zoo1
    cluster.start_zookeeper_nodes(["zoo2", "zoo3"])
    wait_zookeeper_node_to_start(["zoo2", "zoo3"])
    node.query("SELECT COUNT() FROM test_table")
    with pytest.raises(QueryRuntimeException):
        node.query("SELECT COUNT() FROM test_table", settings={"select_sequential_consistency" : 1})

    ## set config to zoo2, server will be normal
    new_config = """
<yandex>
    <zookeeper>
        <node index="1">
            <host>zoo2</host>
            <port>2181</port>
        </node>
        <session_timeout_ms>2000</session_timeout_ms>
    </zookeeper>
</yandex>
"""
    node.replace_config("/etc/clickhouse-server/conf.d/zookeeper.xml", new_config)
    node.query("SYSTEM RELOAD CONFIG")

    assert_eq_with_retry(node, "SELECT COUNT() FROM test_table", '1000', retry_count=120, sleep_time=0.5)