from unittest.mock import patch, MagicMock
from ja4_common.clickhouse import ClickHouseClient, get_client
import ja4_common.clickhouse as ch_module


def test_get_client_singleton():
    ch_module._client = None
    with patch("ja4_common.clickhouse.clickhouse_connect.get_client") as mock_gc:
        mock_client = MagicMock()
        mock_client.ping.return_value = True
        mock_gc.return_value = mock_client
        c1 = get_client()
        c2 = get_client()
        assert c1 is c2


def test_client_reconnects_on_ping_fail():
    client = ClickHouseClient()
    with patch("ja4_common.clickhouse.clickhouse_connect.get_client") as mock_gc:
        mock_inner = MagicMock()
        mock_inner.ping.side_effect = Exception("connection lost")
        mock_gc.return_value = mock_inner
        client._client = mock_inner  # simulate stale connection
        client.connect()  # should reconnect
        assert mock_gc.call_count >= 1


def test_get_client_returns_same_instance_on_second_call():
    """get_client() is a singleton: returns the same object on repeated calls."""
    ch_module._client = None
    with patch("ja4_common.clickhouse.clickhouse_connect.get_client") as mock_gc:
        mock_inner = MagicMock()
        mock_inner.ping.return_value = True
        mock_gc.return_value = mock_inner
        c1 = get_client()
        c2 = get_client()
        assert c1 is c2
        # connect() should have been called once for c1; c2 reuses the same instance
        assert mock_gc.call_count == 1


def test_client_query_delegates_to_inner():
    """ClickHouseClient.query() delegates to the underlying client."""
    client = ClickHouseClient()
    with patch("ja4_common.clickhouse.clickhouse_connect.get_client") as mock_gc:
        mock_inner = MagicMock()
        mock_inner.ping.return_value = True
        mock_inner.query.return_value = "result"
        mock_gc.return_value = mock_inner

        result = client.query("SELECT 1")
        assert result == "result"
        mock_inner.query.assert_called_once_with("SELECT 1", None)


def test_client_query_with_params():
    """ClickHouseClient.query() passes params to the inner client."""
    client = ClickHouseClient()
    with patch("ja4_common.clickhouse.clickhouse_connect.get_client") as mock_gc:
        mock_inner = MagicMock()
        mock_inner.ping.return_value = True
        mock_gc.return_value = mock_inner

        client.query("SELECT %(val)s", {"val": 42})
        mock_inner.query.assert_called_once_with("SELECT %(val)s", {"val": 42})


def test_client_close_sets_client_to_none():
    """ClickHouseClient.close() clears the internal client reference."""
    client = ClickHouseClient()
    with patch("ja4_common.clickhouse.clickhouse_connect.get_client") as mock_gc:
        mock_inner = MagicMock()
        mock_inner.ping.return_value = True
        mock_gc.return_value = mock_inner
        client.connect()  # establish connection
        assert client._client is not None
        client.close()
        assert client._client is None


def test_client_close_when_already_none():
    """ClickHouseClient.close() is safe to call when no connection exists."""
    client = ClickHouseClient()
    client._client = None  # ensure no connection
    client.close()  # should not raise


def test_ping_returns_false_on_exception():
    """_ping() returns False when ping raises."""
    client = ClickHouseClient()
    mock_inner = MagicMock()
    mock_inner.ping.side_effect = Exception("conn reset")
    client._client = mock_inner
    assert client._ping() is False


def test_ping_returns_true_on_success():
    """_ping() returns True when ping succeeds."""
    client = ClickHouseClient()
    mock_inner = MagicMock()
    mock_inner.ping.return_value = True
    client._client = mock_inner
    assert client._ping() is True


def test_ping_returns_false_when_no_client():
    """_ping() returns False when _client is None."""
    client = ClickHouseClient()
    client._client = None
    assert client._ping() is False