"""
serial_client.py — RS485/串口抽象层

封装 pyserial: 端口扫描/打开/关闭/收发, 线程安全。
"""
import threading
import time
from dataclasses import dataclass
from typing import Optional, Callable

import serial
import serial.tools.list_ports


@dataclass
class SerialConfig:
    port: str = ""
    baudrate: int = 9600
    bytesize: int = serial.EIGHTBITS
    parity: str = serial.PARITY_NONE
    stopbits: int = serial.STOPBITS_ONE
    timeout: float = 0.05  # 读超时


class SerialClient:
    """串口客户端 — 后台读线程 + 回调通知"""

    def __init__(self):
        self._ser: Optional[serial.Serial] = None
        self._thread: Optional[threading.Thread] = None
        self._running = False
        self._lock = threading.Lock()
        self._on_data: Optional[Callable[[bytes], None]] = None

    # ── 静态工具 ──────────────────────────────────

    @staticmethod
    def list_ports() -> list[str]:
        return [p.device for p in serial.tools.list_ports.comports()]

    # ── 连接管理 ──────────────────────────────────

    def connect(self, cfg: SerialConfig) -> None:
        self.disconnect()
        self._ser = serial.Serial(
            port=cfg.port,
            baudrate=cfg.baudrate,
            bytesize=cfg.bytesize,
            parity=cfg.parity,
            stopbits=cfg.stopbits,
            timeout=cfg.timeout,
        )
        self._running = True
        self._thread = threading.Thread(target=self._read_loop, daemon=True)
        self._thread.start()

    def disconnect(self) -> None:
        self._running = False
        if self._thread and self._thread.is_alive():
            self._thread.join(timeout=1.0)
        with self._lock:
            if self._ser and self._ser.is_open:
                self._ser.close()
            self._ser = None

    @property
    def is_connected(self) -> bool:
        with self._lock:
            return self._ser is not None and self._ser.is_open

    # ── 发送 ──────────────────────────────────────

    def send(self, data: bytes) -> None:
        with self._lock:
            if self._ser and self._ser.is_open:
                self._ser.write(data)

    # ── 接收回调 ──────────────────────────────────

    def set_data_callback(self, cb: Optional[Callable[[bytes], None]]) -> None:
        self._on_data = cb

    # ── 内部读线程 ────────────────────────────────

    def _read_loop(self) -> None:
        while self._running:
            try:
                with self._lock:
                    if not self._ser or not self._ser.is_open:
                        break
                    waiting = self._ser.in_waiting
                if waiting > 0:
                    with self._lock:
                        data = self._ser.read(waiting)
                    if data and self._on_data:
                        self._on_data(data)
                else:
                    time.sleep(0.01)
            except (serial.SerialException, OSError):
                time.sleep(0.1)