import snap7
import time
import re
from datetime import datetime

from inputs.common import Input

localtz = datetime.now().astimezone().tzinfo

class SiemensCPU(Input):
  interval = 0.02

  def __init__(self):
    super().__init__(self.read_handler)
    self.server = snap7.server.Server(True)
    size = 100
    self.DBdata = (snap7.types.wordlen_to_ctypes[snap7.types.WordLen.Byte.value] * size)()
    self.server.register_area(snap7.types.srvAreaDB, 1, self.DBdata)
    self.server.start(102)

  def read_handler(self):
    event : snap7.types.SrvEvent
    while event := self.server.pick_event():
      timestamp = datetime.now(localtz)
      text = self.server.event_text(event)
      match = re.match("^(?P<datetime>\d+-\d+-\d+ \d+:\d+:\d+) \[(?P<host>[\w\.:]+)\] (?P<type>[\w ]+), Area : (?P<area>.+), Start : (?P<start>\d+), Size : (?P<size>\d+) --> (?P<response>.+)$", text)
      if not match:
        print(text)
        continue
      
      if match.group("type") != "Write request" or match.group("area") != "DB1":
        print(text)
        continue
      
      raw = bytearray(self.DBdata)
      self.queue_ifm_from_bytes("S7", timestamp, raw[0:30])