# -*- coding: utf-8 -*-
"""Modbus 驱动 —— PLC / 称重仪表等 RTU/TCP 从站参数化适配。

连接参数（mode / host / port / slave_id / register_map）来自模板配置；
寄存器映射约定写入点位字典 opcNode 列，格式 `{type}:{addr}`，
type ∈ holding|input|coil|discrete，如 `holding:40001`。
依赖 `pymodbus`，未安装时给出明确提示。
"""
from __future__ import annotations

from typing import Dict, List, Optional

from point_dict.loader import Point
from .base import Driver, SampleValue

_REG_MAP = {"holding": 3, "input": 4, "coil": 1, "discrete": 2}


class ModbusDriver(Driver):
    """Modbus 只读采集驱动（参数化适配）。"""

    protocol = "modbus"

    def __init__(self, config: Optional[dict] = None):
        super().__init__(config)
        self.mode: str = self.config.get("mode", "tcp")  # tcp | rtu
        self.host: str = self.config.get("host", "")
        self.port: int = int(self.config.get("port", 502))
        self.slave_id: int = int(self.config.get("slave_id", 1))
        self._client = None

    def connect(self) -> None:
        try:
            from pymodbus.client import ModbusTcpClient, ModbusSerialClient  # type: ignore
        except ImportError as exc:  # pragma: no cover - 依赖缺失路径
            raise ConnectionError(
                "Modbus 驱动依赖库未安装：请 `pip install pymodbus`"
            ) from exc
        if self.mode == "tcp":
            if not self.host:
                raise ConnectionError("Modbus 驱动缺少配置: drivers.modbus.host")
            self._client = ModbusTcpClient(self.host, port=self.port)
        else:
            self._client = ModbusSerialClient(
                port=self.config.get("port", "COM1"),
                baudrate=self.config.get("baudrate", 9600),
            )
        if not self._client.connect():
            raise ConnectionError(f"Modbus 连接失败: {self.host or self.config.get('port')}")

    def read_points(self, points: List[Point]) -> Dict[str, SampleValue]:
        if self._client is None:
            raise ConnectionError("Modbus 客户端未连接，请先 connect()")
        result: Dict[str, SampleValue] = {}
        for p in points:
            node = (p.opc_node or "").split(":")
            if len(node) != 2 or node[0] not in _REG_MAP:
                continue
            reg_type, addr = node[0], int(node[1])
            try:
                if reg_type == "coil":
                    resp = self._client.read_coils(addr, count=1, slave=self.slave_id)
                elif reg_type == "discrete":
                    resp = self._client.read_discrete_inputs(addr, count=1, slave=self.slave_id)
                else:
                    resp = self._client.read_holding_registers(addr, count=1, slave=self.slave_id) \
                        if reg_type == "holding" else \
                        self._client.read_input_registers(addr, count=1, slave=self.slave_id)
                result[p.point_id] = resp.registers[0] if hasattr(resp, "registers") and resp.registers else None
            except Exception:
                result[p.point_id] = None
        return result

    def close(self) -> None:
        if self._client is not None:
            try:
                self._client.close()
            finally:
                self._client = None