# -*- coding: utf-8 -*-
"""西门子 S7-1200 驱动 —— 参数化适配（issue #24 落点）。

连接参数（ip / rack / slot / db / offset 映射）全部来自模板配置，
点位到 DB 地址的映射通过点位字典 CSV 的 opcNode 列携带
（S7 场景下约定格式 `DB{db}.{byte}.{bit}`，如 DB100.0.0）。
依赖 `python-snap7`，未安装时给出明确提示。
"""
from __future__ import annotations

import re
from typing import Dict, List, Optional

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

_S7_NODE_RE = re.compile(r"^DB(\d+)\.(\d+)(?:\.(\d+))?$")


class S7Driver(Driver):
    """西门子 S7-1200 只读采集驱动（参数化适配）。"""

    protocol = "s7"

    def __init__(self, config: Optional[dict] = None):
        super().__init__(config)
        self.ip: str = self.config.get("ip", "")
        self.rack: int = int(self.config.get("rack", 0))
        self.slot: int = int(self.config.get("slot", 1))
        self._client = None

    def connect(self) -> None:
        try:
            import snap7  # type: ignore
        except ImportError as exc:  # pragma: no cover - 依赖缺失路径
            raise ConnectionError(
                "S7 驱动依赖库未安装：请 `pip install python-snap7`"
            ) from exc
        if not self.ip:
            raise ConnectionError("S7 驱动缺少配置: drivers.s7.ip")
        self._client = snap7.client.Client()
        self._client.connect(self.ip, self.rack, self.slot)

    def read_points(self, points: List[Point]) -> Dict[str, SampleValue]:
        if self._client is None:
            raise ConnectionError("S7 客户端未连接，请先 connect()")
        result: Dict[str, SampleValue] = {}
        for p in points:
            match = _S7_NODE_RE.match(p.opc_node or "")
            if not match:
                continue  # 非 S7 点位由其它驱动采集
            db, byte_, bit = int(match.group(1)), int(match.group(2)), match.group(3)
            try:
                if bit is not None:
                    result[p.point_id] = self._client.read_area(
                        0x84, db, byte_ * 8 + int(bit), 1
                    )[0]
                else:
                    result[p.point_id] = self._client.read_area(0x84, db, byte_, 4)[0]
            except Exception:
                result[p.point_id] = None  # 单点失败不中断整批
        return result

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