import requests
import xml.dom.minidom
import time
import logging
import sys

from pymodbus.client.sync import ModbusTcpClient
from pymodbus.exceptions import ConnectionException

client = None
inputs = dict()
failure = True

logger = logging.getLogger()
logger.setLevel(logging.INFO)
#logger.setLevel(logging.DEBUG)

handler = logging.StreamHandler(sys.stdout)
handler.setLevel(logging.DEBUG)
formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
handler.setFormatter(formatter)
logger.addHandler(handler)


def write_coil(nr, value):
  while True:
    try:
      client.write_coil(nr, value, unit=1)
      return
    except ConnectionException:
      print("Error writing to Modbus, retrying...")
      time.sleep(5)


def poll():
  global failure

  try:
    r = requests.get("http://192.168.43.100/input_emz.xml", timeout=5)
  except Exception:
    logger.debug("Could not get data from EMA. Sending error state!")
    write_coil(501, False)
    failure = True
    return

  if failure:
     write_coil(501, True)
     failure = False

  with xml.dom.minidom.parseString(r.text) as dom:
    for inp in dom.getElementsByTagName('Input'):
      nr = inp.getAttribute('nr')
      led = inp.getElementsByTagName('Led')
      if len(led):
        led = led[0].firstChild.nodeValue
        value = False
        if led == "RED_ON":
          value = True
        if nr not in inputs or inputs[nr] != value:
          inputs[nr] = value
          offset = 399+int(nr)
          logger.info('EMZ-MG: ' + str(nr) + " --> Modbus Coil: " + str(offset) + " State: " + str(value))
          write_coil(int(offset), value)


def loop():
  global client
  try:
    logger.info("Starting EMZ Poller...")
    client = ModbusTcpClient('192.168.43.1')

    while True:
      logger.debug("Polling...")
      poll()
      time.sleep(1)

  except KeyboardInterrupt:
    raise SystemExit(0)
  finally:
    if client is not None:
      client.close()

if __name__ == "__main__":
  loop()