"""Modbus TCP server helpers."""

import asyncio
import logging

from pymodbus.server.requesthandler import ServerRequestHandler
from pymodbus.server.server import ModbusTcpServer

logger = logging.getLogger(__name__)


class LoggingServerRequestHandler(ServerRequestHandler):
    def _client_addr(self) -> str:
        if not self.transport:
            return "unknown"
        peer = self.transport.get_extra_info("peername")
        return "%s:%s" % peer if peer else "unknown"

    def callback_connected(self) -> None:
        super().callback_connected()
        logger.info("客户端已连接（Modbus）: %s", self._client_addr())

    def callback_disconnected(self, exc: Exception | None) -> None:
        client_addr = self._client_addr()
        super().callback_disconnected(exc)
        if exc:
            logger.info("客户端已断开（Modbus）: %s, 原因=%s", client_addr, exc)
        else:
            logger.info("客户端已断开（Modbus）: %s", client_addr)


class LoggingModbusTcpServer(ModbusTcpServer):
    def callback_new_connection(self):
        return LoggingServerRequestHandler(
            self,
            self.trace_packet,
            self.trace_pdu,
            self.trace_connect,
        )


async def start_modbus_server(context, host: str, port: int) -> None:
    server = LoggingModbusTcpServer(
        context,
        address=(host, port),
        ignore_missing_devices=False,
        broadcast_enable=False,
    )
    logger.info("服务已启动监听（Modbus TCP），地址=%s:%s", host, port)
    await server.serve_forever()


def run_modbus_server(context, host: str, port: int) -> None:
    asyncio.run(start_modbus_server(context, host, port))