#!/usr/bin/env python3
import ssl, socket, subprocess, time
import configparser

CONFIG = "ding_server.cfg"

def getTimestamp():
  t = "[" + time.strftime("%Y-%m-%d %H:%M:%S") + "]"
  return t

def execFromConfig(option):
  cfg = configparser.SafeConfigParser()
  cfg.read(CONFIG)  

  try:
    cmd = cfg.get("Commands", option).replace("\"", "").replace("\'", "")
    cmd = cmd.split(" ")
    try:
      subprocess.Popen(cmd)
      return 0

    except FileNotFoundError:
      print(getTimestamp(), "Can't execute", cmd, ". File not found.")
      return 2

  except configparser.NoOptionError:
    print(getTimestamp(), "No execution set:", option)
    return 1


  
def main():

  while True:
    newsocket, fromaddr = bindsocket.accept()
    try:
      connstream = context.wrap_socket(newsocket, server_side=True)    
      print(getTimestamp(), "Incoming connection:", fromaddr[0])
      connstream.send(b"OK 1337\n")
      
      con_loop = True
      while con_loop:
        try:
          buf = connstream.recv(1024)
          if not buf: break
          buf = buf.decode("utf-8").upper()
        except ssl.SSLEOFError:
          print(getTimestamp(), "SSL-EOF-Error.")
          con_loop = False
        except ConnectionResetError:
          print(getTimestamp(), "Connection reset.")
          serve()
        
        print(getTimestamp(), " ", fromaddr[0], ": ", buf, sep="")

        retval = execFromConfig(buf)
        if(retval == 0):
          connstream.send(b"OK CMD")
        elif(retval == 1):
          connstream.send(b"ERR NO_CMD")
        elif(retval == 2):
          connstream.send(b"ERR CMD_ERR")
        

    except ssl.SSLError as e:
      print(getTimestamp(), e)

    except EOFError:
      print(getTimestamp(), "EOF")

def init():

  global host, port, cafile, certfile, keyfile, context, bindsocket
  
  cfg = configparser.SafeConfigParser()
  cfg.read(CONFIG)

  try:
    host=cfg.get("Server", "host").replace("\"","").replace("\'","")
    port=int(cfg.get("Server", "port").replace("\"","").replace("\'",""))
    cafile=cfg.get("Security", "cafile").replace("\"","").replace("\'","")
    certfile=cfg.get("Security", "certfile").replace("\"","").replace("\'","")
    keyfile=cfg.get("Security", "keyfile").replace("\"","").replace("\'","")
  except configparser.NoOptionError as e:
    print("Error in configuration file:", e)
    quit(1)


  try:
    context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH, cafile=cafile)
    context.load_cert_chain(certfile=certfile, keyfile=keyfile)
    context.verify_mode = ssl.CERT_REQUIRED
    context.load_verify_locations(cafile=cafile)

  except FileNotFoundError as e:
    print(e)
    print("Please check your paths in the config file. (Have you forgotten to generate the Certificates?)")
    quit(2)

  try:
    bindsocket = socket.socket()
    bindsocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    bindsocket.bind((host, port))
    bindsocket.listen(5)
  except socket.gaierror:
    print("Error: Hostname error. Name or service not known.")
    quit(1)
  except PermissionError:
    print("Error: Can't bind for port number ", port, ". Permission denied.", sep="")
    quit(1)
 
  print("Running ding server on ", host, ":", port, 
        "\nCAFile: ", cafile, 
        "\nCertfile: ", certfile, 
        "\nKeyfile: ", keyfile,
        "\n===========",
        sep="")
 

if(__name__ == "__main__"):

  try:
    init()
    main()
  except KeyboardInterrupt:
    print("\r\rServer stopped.")