#!/usr/bin/env python3

import datetime, time, sys, os, serial, signal
import paho.mqtt.client as paho

serial_port = "/dev/ttyUSB1"
serial_bps = 9600

MQTT_ADDRESS = '192.168***'
MQTT_PORT = 1883
MQTT_USER = '***'
MQTT_PASSWORD = '***'
MQTT_TOPIC = 'itr/*****'
MQTT_CLIENT_ID = 'serial2mqtt'
mqtt = None
last_value = {}
precision = 3
verbose = 0

def debug(*args, end='\n'):
	if verbose:
		for i in list(args):
			print(i, end='')
		print(end, end='')

def search_key(code):
	for key in obis_keys:
		if key[0] == code:
			return key

# OBIS-Kennzahl, Textbeschreibung, mqtt-topic, encoding
obis_keys = [
	[ b'\x01\x00\x60\x01\x00\xFF', 'Seriennummer', 'serial', 'serial'],
    [ b'\x01\x00\x60\x32\x01\x01', 'Hersteller-Identifikation', 'manufacturer', 'bytes'],
#    [ b'\x01\x00\x00\x00\x09\xFF', 'Server-Id / Geraeteeinzelidentifikation', 'server-id'],
    [ b'\x01\x00\x01\x08\x00\xFF', 'Zaehlwerk pos. Wirkenergie (Bezug), tariflos', 'import/total'],
    [ b'\x01\x00\x01\x08\x01\xFF', 'Zaehlwerk pos. Wirkenergie (Bezug), Tarif 1', 'import/tarif_1/total'],
#    [ b'\x01\x00\x01\x08\x02\xFF', 'Zaehlwerk pos. Wirkenergie (Bezug), Tarif 2', 'import/tarif_2/total'],
    [ b'\x01\x00\x02\x08\x00\xFF', 'Zaehlwerk neg. Wirkenergie (Einspeisung), tariflos', 'export/total'],
#    [ b'\x01\x00\x02\x08\x01\xFF', 'Zaehlwerk neg. Wirkenergie (Einspeisung), Tarif 1', 'export/tarif_1/total'],
#    [ b'\x01\x00\x02\x08\x02\xFF', 'Zaehlwerk neg. Wirkenergie (Einspeisung), Tarif 2', 'export/tarif_2/total'],
    [ b'\x01\x00\x01\x07\x00\xFF', 'Aktuelle Wirkleistung gesamt', 'import/power'],
#    [ b'\x01\x00\x24\x07\x00\xFF', 'Aktuelle Wirkleistung L1', 'l1/power'],
#    [ b'\x01\x00\x38\x07\x00\xFF', 'Aktuelle Wirkleistung L2', 'l2/power'],
#    [ b'\x01\x00\x4c\x07\x00\xFF', 'Aktuelle Wirkleistung L3', 'l3/power'],
#    [ b'\x81\x81\xC7\x82\x05\xFF', 'Public Key', 'public_key']
]

# https://github.com/volkszaehler/libsml/blob/master/examples/unit.h
obis_unit = {
	0:'',
	27:'W',
	28:'VA',
	30:'Wh',
	33:'A',
	35:'V',
	44:'Hz'
}

crc16_x25_table = [
	0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD,	0x6536, 0x74BF,
	0x8C48, 0x9DC1, 0xAF5A, 0xBED3, 0xCA6C, 0xDBE5, 0xE97E, 0xF8F7,
	0x1081, 0x0108,	0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E,
	0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64,	0xF9FF, 0xE876,
	0x2102, 0x308B, 0x0210, 0x1399,	0x6726, 0x76AF, 0x4434, 0x55BD,
	0xAD4A, 0xBCC3,	0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5,
	0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E,	0x54B5, 0x453C,
	0xBDCB, 0xAC42, 0x9ED9, 0x8F50,	0xFBEF, 0xEA66, 0xD8FD, 0xC974,
	0x4204, 0x538D,	0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB,
	0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1,	0xAB7A, 0xBAF3,
	0x5285, 0x430C, 0x7197, 0x601E,	0x14A1, 0x0528, 0x37B3, 0x263A,
	0xDECD, 0xCF44,	0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72,
	0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB,	0x0630, 0x17B9,
	0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5,	0xA96A, 0xB8E3, 0x8A78, 0x9BF1,
	0x7387, 0x620E,	0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738,
	0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862,	0x9AF9, 0x8B70,
	0x8408, 0x9581, 0xA71A, 0xB693,	0xC22C, 0xD3A5, 0xE13E, 0xF0B7,
	0x0840, 0x19C9,	0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF,
	0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324,	0xF1BF, 0xE036,
	0x18C1, 0x0948, 0x3BD3, 0x2A5A,	0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E,
	0xA50A, 0xB483,	0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5,
	0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF,	0x4C74, 0x5DFD,
	0xB58B, 0xA402, 0x9699, 0x8710,	0xF3AF, 0xE226, 0xD0BD, 0xC134,
	0x39C3, 0x284A,	0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C,
	0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1,	0xA33A, 0xB2B3,
	0x4A44, 0x5BCD, 0x6956, 0x78DF,	0x0C60, 0x1DE9, 0x2F72, 0x3EFB,
	0xD68D, 0xC704,	0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232,
	0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68,	0x3FF3, 0x2E7A,
	0xE70E, 0xF687, 0xC41C, 0xD595,	0xA12A, 0xB0A3, 0x8238, 0x93B1,
	0x6B46, 0x7ACF,	0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9,
	0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022,	0x92B9, 0x8330,
	0x7BC7, 0x6A4E, 0x58D5, 0x495C,	0x3DE3, 0x2C6A, 0x1EF1, 0x0F78]

def crc16_x25(Buffer):
	crcsum = 0xffff
	global crc16_x25_table
	for byte in Buffer:
		crcsum = crc16_x25_table[(byte ^ crcsum) & 0xff] ^ (crcsum >> 8 & 0xff)
	crcsum ^= 0xffff
	return crcsum

def parse_SML_file(sml):
	obis_list = []
	active_list = None

	# Telegramm prüfen
	start = b'\x1b\x1b\x1b\x1b\x01\x01\x01\x01'
	end = b'\x1b\x1b\x1b\x1b\x1a'
	debug(sml.hex())

	try:
		message = sml[0:-2]	#letzen beiden Bytes wegschneiden
		crc_rx = int.from_bytes([sml[-1], sml[-2]], 'big')	#CRC Bytes umgedreht in eine Variable speichern
		#print("crc: " + str(crc_rx))
	except IndexError:
		debug("Error: SML CRC")
		return

	#print("message: " + message[0:8].hex() + "\tstart: " + start.hex())

	if message[0:8] != start:	#die ersten 8 Bytes prüfen
		debug("Error: SML start")
		return

	#print("message: " + message[-5:].hex() + "\tend: " + end.hex())

	if message[-6:-1] != end:	#die letzten 5 Bytes prüfen
		debug("Error: SML end")
		return

	crc_calc = crc16_x25(message)	#eigene Prüfsumme bilden
	if crc_rx != crc_calc:	#Prüfsummen vergleichen
		debug("Error: CRC")
		return

	level = [0]
	index = [0]
	x = 0

	sml = sml[8:] # Start abschneiden
#	debug(sml.hex())

	while x < len(sml):
		while level:
			if level[-1] == 0:
				level.pop()
				index.pop()
				active_list = False
			else:
				break
		if not level and sml[x] == 0x1B:
			break

		if level:
			if level[-1]:
				level[-1] -= 1
				index[-1] += 1

		debug(level, end=' ')
		if index:
			debug(index[-1], end='')
		debug("\n\t\t", end='')

		for i in range(0, len(level)):
			debug('  ', end='')

		debug("%02X" % sml[x], end='')

		prefix = sml[x].to_bytes(1, byteorder='big')

		al = (sml[x] & 0x0F) - 1
		buf = 0

		if (sml[x] & 0x80) == 0x80:
			# Extended length
			x += 1
			prefix += sml[x].to_bytes(1, byteorder='big')
			debug("+%02X" % sml[x], end='')
			if sml[x] & 0x70:
				debug(" Unsupported!")
			al = ((sml[x-1] & 0x0F) << 4) | (sml[x] & 0x0F) - 2

		debug(": ", end='')

		if sml[x] & 0x70 == 0x70:
			# List of
			level.append(sml[x] & 0x0F)
			index.append(0)
		elif sml[x] & 0x7F == 0x00:
			# EndOfSmlMsg
			debug ("EndOfSmlMSg")
		elif sml[x] & 0x70 == 0x00:
			# Octet String
			buf = sml[x+1:x+1+al]
			x += al
			for i in buf:
				debug("%02X " % i, end='')

			if index:
				if index[-1] == 1 and al == 6:
					key = search_key(buf)
					if key is not None:
						debug("\t# OBIS " + key[1])
						obis_list.append([key])
						active_list = True

		elif sml[x] & 0x70 == 0x50:
			# IntergerX
			buf = sml[x+1:x+1+al]
			x += al
			for i in buf:
				debug("%02X " % i, end='')
		elif sml[x] & 0x70 == 0x60:
			# UnsignedX
			buf = sml[x+1:x+1+al]
			x += al
			for i in buf:
				debug("%02X "% i, end='')
		else:
			debug(" Unsupported!")

		if active_list:
			obis_list[-1].append(prefix)
			obis_list[-1].append(buf)

		debug("") # "\n"
		x +=1

	return obis_list

def parse_SML_entry(data):
	key = data[0]
	debug("Entries:\t%d" % data[1][0])

	debug("OBIS-Code:\t", end='')
	obis_code = ''
	sep = '-:..'
	for i in range(0, 5):
		obis_code += '%d' % data[2][i]
		if i != 4:
			obis_code += sep[i]

	debug(obis_code)
	debug("Text:\t" + key[1])
	debug("status:\t%02X" % data[3][0] + "\t" + data[4].hex())
	debug("valTime:%02X" % data[5][0] + "\t" + data[6].hex())
	debug("unit:\t%02X" % data[7][0] + "\t" + data[8].hex())
	debug("scaler:\t%02X" % data[9][0] + "\t" + data[10].hex())
	debug("value:\t%02X" % data[11][0] + "\t" + data[12].hex())
	debug("valueSignature:\t%02X" % data[13][0] + "\t" + data[14].hex())

	sml_unit = [data[7][0], data[8]]
	sml_scaler = [data[9][0], data[10]]
	sml_value = [data[11][0], data[12]]
	num = data[12]

	signed = sml_scaler[0] & 0x70 == 0x50
	scaler = int.from_bytes(sml_scaler[1], byteorder="big", signed=signed)

	# get unit
	if len(sml_unit[1]) > 0:
		unit = obis_unit.get(sml_unit[1][0], '')
	else:
		unit = ''

	# decode byte-string
	if key[3:4] == ['bytes']:
		value = num.decode()
	elif key[3:4] == ['serial']:
		value = str(num[1:2][0]) + num[2:5].decode() + num[5:6].hex() + str(int(num[6:].hex(), 16))
	else:
		signed = sml_value[0] & 0x70 == 0x50
		value = int.from_bytes(sml_value[1], byteorder="big", signed=signed) * (10 ** scaler)

	# Wh -> kWh
	if unit == 'Wh':
		value = float(round(value / 1000, precision))
		unit = 'k' + unit

	debug("Wert: " + str(value) + " " + unit)
	debug("")

#	# Update only if new value
#	if last_value.get(obis_code) != value:
#		last_value[obis_code] = value
#		mqtt_publish(key[2], value)

mqtt_error = {
	0: 'Connection successful',
	1: 'Incorrect protocol version',
	2: 'Invalid client identifier',
	3: 'Server unavailable',
	4: 'Bad username or password',
	5: 'Not authorised'
}

def mqtt_on_connect(client, userdata, flags, rc):
	if rc == 0:
		debug('Connected to mqtt broker')
		mqtt_publish('status', 'online')
	else:
		print('mqtt connection failed: ' + mqtt_error[rc])

#def mqtt_on_publish(client, userdata, result):
#	pass

def mqtt_publish(topic, value):
	ret = mqtt.publish(MQTT_TOPIC + '/' + topic, value, retain=True)
	if ret.rc != 0:
		print('Error: mqtt publish failed')

def exit_handler(sig, frame):
	if verbose:
		print("Signal:" + str(sig))
	ser.close()
	mqtt_publish('status', 'disconnect')
	mqtt.disconnect()
	# send out last publish
	mqtt.loop_forever()
	sys.exit()

if __name__ == '__main__':
	# Kommandozeile prüfen
	verbose = True
	sml = ''

	if len(sys.argv) > 1:
		for i in sys.argv[1:]:
			sml += i

		sml = bytearray.fromhex(sml)

		result = parse_SML_file(sml)
		if result:
			for i in result:
				if verbose:
					print(i)
					print()
				parse_SML_entry(i)

	sys.exit()


	signal.signal(signal.SIGTERM, exit_handler)
	signal.signal(signal.SIGINT,  exit_handler)

	if verbose:
		print('Serial to MQTT bridge')

	mqtt = paho.Client(MQTT_CLIENT_ID)
	mqtt.username_pw_set(MQTT_USER, MQTT_PASSWORD)
	mqtt.will_set(MQTT_TOPIC + '/' + 'status', 'offline', qos=0, retain=True)
#	mqtt.on_publish = mqtt_on_publish
	mqtt.on_connect = mqtt_on_connect
	#mqtt.on_message = on_message
	mqtt.connect(MQTT_ADDRESS, MQTT_PORT)
	mqtt.loop_start()

	ser = serial.Serial(
			port=serial_port,
			baudrate=serial_bps,
			parity=serial.PARITY_NONE,
			stopbits=serial.STOPBITS_ONE,
			bytesize=serial.EIGHTBITS,
			timeout=0.2,
			xonxoff=False,
			rtscts=False,
			dsrdtr=False)
	ser.flushInput()
	ser.flushOutput()

	while True:
		sml = b''
		while True:
			try:
				received = ser.read(50)
			except serial.serialutil.SerialException:
				debug("Error reading serial port")
				sys.exit()
			if not received:
				#time.sleep(5)
				break
			sml += received

		if sml:
			result = parse_SML_file(sml)
			if result:
				for i in result:
					if verbose:
						print(i)
						print()
					parse_SML_entry(i)