import time
import pytest

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


cluster = ClickHouseCluster(__file__)

def _fill_nodes(nodes, table_name):
    for node in nodes:
        node.query(
            '''
            CREATE DATABASE IF NOT EXISTS test;
            CREATE TABLE IF NOT EXISTS {0}(date Date, id UInt32)
            ENGINE = ReplicatedMergeTree('/clickhouse/tables/test/{0}', '{1}')
            ORDER BY id PARTITION BY toYYYYMM(date);
            '''.format(table_name, node.name)
        )

node1 = cluster.add_instance('node1', main_configs=['configs/listen_host.xml'], with_zookeeper=True, ipv6_address='2001:3984:3989::1:1111')
node2 = cluster.add_instance('node2', main_configs=['configs/listen_host.xml', 'configs/dns_update_long.xml'],
    with_zookeeper=True, ipv6_address='2001:3984:3989::1:1112')

@pytest.fixture(scope="module")
def cluster_without_dns_cache_update():
    try:
        cluster.start()

        _fill_nodes([node1, node2], 'test_table_drop')

        yield cluster

    except Exception as ex:
        print ex

    finally:
        cluster.shutdown()
        pass

# node1 is a source, node2 downloads data
# node2 has long dns_cache_update_period, so dns cache update wouldn't work
def test_ip_change_drop_dns_cache(cluster_without_dns_cache_update):
    # First we check, that normal replication works
    node1.query("INSERT INTO test_table_drop VALUES ('2018-10-01', 1), ('2018-10-02', 2), ('2018-10-03', 3)")
    assert node1.query("SELECT count(*) from test_table_drop") == "3\n"
    assert_eq_with_retry(node2, "SELECT count(*) from test_table_drop", "3")

    # We change source node ip
    cluster.restart_instance_with_ip_change(node1, "2001:3984:3989::1:7777")

    # Put some data to source node1
    node1.query("INSERT INTO test_table_drop VALUES ('2018-10-01', 5), ('2018-10-02', 6), ('2018-10-03', 7)")
    # Check that data is placed on node1
    assert node1.query("SELECT count(*) from test_table_drop") == "6\n"

    # Because of DNS cache dest node2 cannot download data from node1
    with pytest.raises(Exception):
        assert_eq_with_retry(node2, "SELECT count(*) from test_table_drop", "6")

    # drop DNS cache
    node2.query("SYSTEM DROP DNS CACHE")
    # Data is downloaded
    assert_eq_with_retry(node2, "SELECT count(*) from test_table_drop", "6")

    # Just to be sure check one more time
    node1.query("INSERT INTO test_table_drop VALUES ('2018-10-01', 8)")
    assert node1.query("SELECT count(*) from test_table_drop") == "7\n"
    assert_eq_with_retry(node2, "SELECT count(*) from test_table_drop", "7")


node3 = cluster.add_instance('node3', main_configs=['configs/listen_host.xml'],
    with_zookeeper=True, ipv6_address='2001:3984:3989::1:1113')
node4 = cluster.add_instance('node4', main_configs=['configs/remote_servers.xml', 'configs/listen_host.xml', 'configs/dns_update_short.xml'],
    with_zookeeper=True, ipv6_address='2001:3984:3989::1:1114')
node5 = cluster.add_instance('node5', main_configs=['configs/listen_host.xml', 'configs/dns_update_short.xml'],
                             user_configs=['configs/users_with_hostname.xml'], ipv6_address='2001:3984:3989::1:1115')

@pytest.fixture(scope="module")
def cluster_with_dns_cache_update():
    try:
        cluster.start()

        _fill_nodes([node3, node4], 'test_table_update')

        yield cluster

    except Exception as ex:
        print ex

    finally:
        cluster.shutdown()
        pass

# node3 is a source, node4 downloads data
# node4 has short dns_cache_update_period, so testing update of dns cache
def test_ip_change_update_dns_cache(cluster_with_dns_cache_update):
    # First we check, that normal replication works
    node3.query("INSERT INTO test_table_update VALUES ('2018-10-01', 1), ('2018-10-02', 2), ('2018-10-03', 3)")
    assert node3.query("SELECT count(*) from test_table_update") == "3\n"
    assert_eq_with_retry(node4, "SELECT count(*) from test_table_update", "3")

    # We change source node ip
    cluster.restart_instance_with_ip_change(node3, "2001:3984:3989::1:8888")

    # Put some data to source node3
    node3.query("INSERT INTO test_table_update VALUES ('2018-10-01', 5), ('2018-10-02', 6), ('2018-10-03', 7)")
    # Check that data is placed on node3
    assert node3.query("SELECT count(*) from test_table_update") == "6\n"

    # Because of DNS cache update, ip of node3 would be updated
    assert_eq_with_retry(node4, "SELECT count(*) from test_table_update", "6")

    # Just to be sure check one more time
    node3.query("INSERT INTO test_table_update VALUES ('2018-10-01', 8)")
    assert node3.query("SELECT count(*) from test_table_update") == "7\n"
    assert_eq_with_retry(node4, "SELECT count(*) from test_table_update", "7")

def set_hosts(node, hosts):
    new_content = '\\n'.join(['127.0.0.1 localhost', '::1 localhost'] + hosts)
    node.exec_in_container(['bash', '-c', 'echo -e "{}" > /etc/hosts'.format(new_content)], privileged=True, user='root')

def test_dns_cache_update(cluster_with_dns_cache_update):
    set_hosts(node4, ['127.255.255.255 lost_host'])

    with pytest.raises(QueryRuntimeException):
        node4.query("SELECT * FROM remote('lost_host', 'system', 'one')")

    node4.query("CREATE TABLE distributed_lost_host (dummy UInt8) ENGINE = Distributed(lost_host_cluster, 'system', 'one')")
    with pytest.raises(QueryRuntimeException):
        node4.query("SELECT * FROM distributed_lost_host")

    set_hosts(node4, ['127.0.0.1 lost_host'])

    # Wait a bit until dns cache will be updated
    assert_eq_with_retry(node4, "SELECT * FROM remote('lost_host', 'system', 'one')", "0")
    assert_eq_with_retry(node4, "SELECT * FROM distributed_lost_host", "0")

    assert TSV(node4.query("SELECT DISTINCT host_name, host_address FROM system.clusters WHERE cluster='lost_host_cluster'")) == TSV("lost_host\t127.0.0.1\n")
    assert TSV(node4.query("SELECT hostName()")) == TSV("node4")

def test_user_access_ip_change(cluster_with_dns_cache_update):
    assert node3.query("SELECT * FROM remote('node5', 'system', 'one')") == "0\n"
    assert node4.query("SELECT * FROM remote('node5', 'system', 'one')") == "0\n"

    set_hosts(node5, ['127.255.255.255 node3', '2001:3984:3989::1:8884 unknown_host'])

    cluster.restart_instance_with_ip_change(node3, "2001:3984:3989::1:8883")
    cluster.restart_instance_with_ip_change(node4, "2001:3984:3989::1:8884")

    with pytest.raises(QueryRuntimeException):
        node3.query("SELECT * FROM remote('node5', 'system', 'one')")
    with pytest.raises(QueryRuntimeException):
        node4.query("SELECT * FROM remote('node5', 'system', 'one')")
    # now wrong addresses are cached

    set_hosts(node5, [])
    # client is not allowed to connect, so execute it directly in container to send query from localhost
    node5.exec_in_container(['bash', '-c', 'clickhouse client -q "SYSTEM DROP DNS CACHE"'], privileged=True, user='root')

    assert node3.query("SELECT * FROM remote('node5', 'system', 'one')") == "0\n"
    assert node4.query("SELECT * FROM remote('node5', 'system', 'one')") == "0\n"