from machine import Pin

SENSOR_READ_PERIOD = const(1)

import onewire, ds18x20, time

class Sensor:
  last_read_time: int
  last_result: int

  sensor: ds18x20.DS18X20
  rom: Any

  def __init__(self, sensor_data_pin: Pin) -> None:
    self.last_read_time = time.time()
    self.last_result = 28
    self.sensor = ds18x20.DS18X20(onewire.OneWire(sensor_data_pin))
    roms = self.sensor.scan()
    assert len(roms) == 1, "Not (only) one sensor on the bus"
    self.rom = roms[0]

  def __should_read_data(self) -> bool:
    return (time.time() - self.last_read_time) > SENSOR_READ_PERIOD

  def read(self) -> int:
    if not self.__should_read_data():
      return self.last_result

    sensor = self.sensor

    try:
      sensor.convert_temp()
      result = sensor.read_temp(self.rom)
      self.last_result = result
      self.last_read_time = time.time()
    except OSError as e:
      print("err reading sensor", e)
      return self.last_result

    return result