import asyncio
from tasks import ATask
from ws.message import MsgIo
from utils.value import ChangedFloat
from components import ATemperatureSensor


class TempSensorTask(ATask):
	def __init__(self, sensor_device: ATemperatureSensor, interval, msg_handler: MsgIo):
		ATask.__init__(self, interval)

		self.msg_handler = msg_handler
		msg_handler.set_recv_handler(self.recv)
		self.sensor = sensor_device
		# Prime before registering - temperature() sets self.sensor.temp,
		# which would otherwise fire on_temp_changed() (and its
		# asyncio.create_task()) before the event loop is running, since
		# all tasks are built synchronously at module level in brewpi.py.
		# Guarded even though TempSensor_max31865.temperature() already
		# catches its own read/reopen failures - belt-and-suspenders
		# against a still-unanticipated exception crashing server startup
		# entirely (same lesson as HeaterTask/StirrerTask's own outer
		# guards - see tasks/heater.py's on_process()).
		try:
			self.sensor.temperature()
		except Exception as e:
			print(f"TempSensorTask: comm error priming sensor: {e}")
		self.sensor.set_on_changed("temp", ChangedFloat(self.on_temp_changed, prec=1).set)

	def on_temp_changed(self, value):
		asyncio.create_task(self.send({'Temp': value}))

	async def recv(self, data):
		pass

	async def send(self, data):
		await self.msg_handler.send(data)

	async def on_process(self):
		# Guarded for the same reason as the priming call above - nothing
		# restarts a dead ATask, so an exception escaping this loop would
		# permanently stop this sensor from ever being read again.
		while True:
			try:
				self.sensor.temperature()
			except Exception as e:
				print(f"TempSensorTask: comm error reading sensor: {e}")
			await asyncio.sleep(self.interval)