#
# Copyright (C) 2025-present ScyllaDB
#
# SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
#
import logging
import pytest
import asyncio

from test.pylib.manager_client import ManagerClient
from test.cluster.util import check_token_ring_and_group0_consistency

logger = logging.getLogger(__name__)


@pytest.mark.asyncio
async def test_left_node_notification(manager: ManagerClient) -> None:
    """
    Create a 3-node multi-DC cluster with 2 nodes in dc1 and 1 node in dc2.
    Then decommission both dc1 nodes, ensuring the topology remains consistent
    and the remaining node belongs to dc2 and there is only two 'left the cluster'
    notifications were issued
    """
    # Bootstrap 2 nodes in dc1
    logger.info("Bootstrapping dc1 nodes")
    dc1_node_a = await manager.server_add(property_file={"dc": "dc1", "rack": "r1"})
    dc1_node_b = await manager.server_add(property_file={"dc": "dc1", "rack": "r2"})

    # Bootstrap 1 node in dc2 with storage_service debug logging
    logger.info("Bootstrapping dc2 node with storage_service=debug")
    dc2_node = await manager.server_add(cmdline=["--logger-log-level", "storage_service=debug"],
                                        property_file={"dc": "dc2", "rack": "r1"})

    # Ensure ring and group0 are consistent before operations
    await check_token_ring_and_group0_consistency(manager)

    # Decommission both dc1 nodes
    logger.info(f"Decommissioning dc1 node {dc1_node_b}")
    await manager.decommission_node(dc1_node_b.server_id)
    await check_token_ring_and_group0_consistency(manager)

    logger.info(f"Decommissioning dc1 node {dc1_node_a}")
    await manager.decommission_node(dc1_node_a.server_id)
    await check_token_ring_and_group0_consistency(manager)

    # Verify only dc2 node remains running
    running = await manager.running_servers()
    assert len(running) == 1, f"Expected 1 running server, found {len(running)}: {running}"
    assert running[0].datacenter == "dc2", f"Remaining node should be in dc2, got {running[0].datacenter}"
    logger.info("Successfully decommissioned both dc1 nodes; dc2 node remains running")

    # Check the remaining node's log contains exactly two 'Notify node … has left the cluster'
    log = await manager.server_open_log(dc2_node.server_id)
    left_msgs = await log.grep(r"Notify node .* has left the cluster")
    assert len(left_msgs) == 2, f"Expected exactly 2 'left the cluster' notifications, got {len(left_msgs)}"