import utime
from machine import Pin


class MTS102:
    """MTS102（三脚二档钮子开关）"""

    def __init__(self, pin, pull_down=False):
        """
        :param pin: 引脚编号
        :param pull_down: 引脚下拉电阻（断开为低电平，接通为高电平），默认为False。若使用下拉电阻，因钮子接通后断开可能存留电荷/漏电故需在引脚和GND并联1K～10K欧电阻
        """
        if not isinstance(pull_down, bool):
            raise TypeError("pull_down数据类型应为布尔")

        self.pull_down = pull_down

        # 尝试初始化引脚
        try:
            self.pin = Pin(
                pin, Pin.IN, Pin.PULL_DOWN if self.pull_down else Pin.PULL_UP
            )
        except Exception as exception:
            raise RuntimeError(f"初始化引脚发生异常，{str(exception)}") from exception

        # 初始化上一次检测时间
        self._last_time = utime.ticks_ms()
        # 初始化上一次检测状态
        self._last_state = self._get_state()

    def _get_state(self):
        """获取状态：0为断开，1为接通"""
        return self.pin.value() ^ (not self.pull_down)

    def _debounce(self):
        """去抖"""
        current_time = utime.ticks_ms()
        current_state = self._get_state()

        # 若当前与上一次检测间隔大于等于防抖时间则更新时间，又若状态不同则更新状态
        if utime.ticks_diff(current_time, self._last_time) >= 20:
            if current_state != self._last_state:
                self._last_time = current_time
                self._last_state = current_state

        return self._last_state

    @property
    def switched(self):
        """是否接通"""
        return self._debounce() == 1


"""
使用示例

引脚0→LED→220R→GND
引脚1→MTS102→GND

import utime
from machine import Pin
from utils.switch import MTS102

led = Pin(0, Pin.OUT)
toggle = MTS102(pin=1)

while True:
    if toggle.switched:
        led.on()
    else:
        led.off()

    utime.sleep_ms(200)
"""