import logging
import asyncio
import serial

log = logging.getLogger('serial-device')

def _zebra_beep(beep_id):
	command = [0x05, 0xE6, 0x04, 0x00, beep_id]
	checksum = (~sum(command) + 1)
	return bytes(command) + (checksum&0xffff).to_bytes(2, 'big')

def _honeywell_beep(beep_id):
	return b"0\x1b" + f"{beep_id}".encode('ASCII') + b','

_beep_map = {
	'ack': {'zebra': _zebra_beep(5), 'honeywell': _honeywell_beep(7)},
	'nack': {'zebra': _zebra_beep(15), 'honeywell': _honeywell_beep('b')},
	'err': {'zebra': _zebra_beep(16), 'honeywell': _honeywell_beep(8)}
}

class SerialDevice:
	def __init__(self, path, mm, brand):
		self.path = path
		self.ser = None
		self.run = False
		self.mm = mm
		self.brand = None

	def start(self):
		self.run = True
		asyncio.create_task(self.loop())

	def stop(self):
		self.run = False

	async def loop(self):
		with serial.Serial(self.path) as ser:

			# Flush data that was sent during startup
			ser.reset_input_buffer()

			self.ser = ser
			while self.run:
				try:
					await self.cycle(ser)
				except Exception as e:
					log.error(f"Halting serial loop due to exception {e}")
					return

	async def cycle(self, ser):

		buf = b''

		# Try to read all the remaining data
		while ser.in_waiting:
			buf += ser.read()
		else:
			if not buf:
				# Sleep until data is available
				while not ser.in_waiting:
					await asyncio.sleep(0.1) # If there is no data, sleep
				return

		# We have data, let's apply some basic cleaning
		buf = buf.strip(b"\r\n") # Remove line break

		log.debug(f"RECV {buf}")
		res = await self.mm.send_event("BarcodeScan", {'content': buf.decode('ASCII')}, ack=True)

		if beep := res.get('beep'):
			if beep not in _beep_map:
				beep = 'nack'

			if self.brand in _beep_map[beep]:
				log.debug(f"BEEP {beep}")
				ser.write(_beep_map[beep][brand])

			# Reset the input buffer (discard the response)
			# TODO: make this more elegant
			async with asyncio.timeout(0.5):
				ser.read()
				ser.reset_input_buffer()