#!/usr/bin/env python
# -*- coding: utf-8 -*-

#This file is part of Beremiz, a Integrated Development Environment for
#programming IEC 61131-3 automates supporting plcopen standard and CanFestival. 
#
#Copyright (C) 2007: Edouard TISSERANT and Laurent BESSARD
#
#See COPYING file for copyrights details.
#
#This library is free software; you can redistribute it and/or
#modify it under the terms of the GNU General Public
#License as published by the Free Software Foundation; either
#version 2.1 of the License, or (at your option) any later version.
#
#This library is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#General Public License for more details.
#
#You should have received a copy of the GNU General Public
#License along with this library; if not, write to the Free Software
#Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

import Zeroconf, socket, threading

class ServicePublisher():
    def __init__(self):
        # type: fully qualified service type name
        self.service_type = '_PYRO._tcp.local.'
        # properties: dictionary of properties (or a string holding the bytes for the text field)
        self.serviceproperties = {'description':'Beremiz remote PLC'}
        
        self.name = None
        self.ip_32b = None
        self.port = None
        self.server = None
        self.service_name = None
        self.retrytimer = None
        
    def RegisterService(self, name, ip, port):
        try:
            self._RegisterService(name, ip, port)
        except Exception,e:
            self.retrytimer = threading.Timer(2,self.RegisterService,[name, ip, port])
            self.retrytimer.start() 

    def _RegisterService(self, name, ip, port):
        # name: fully qualified service name
        self.service_name = 'Beremiz_%s.%s'%(name,self.service_type)
        self.name = name
        self.port = port

        self.server = Zeroconf.Zeroconf(ip)
        print "MDNS brodcasting on :"+ip

        if ip == "0.0.0.0":
            ip = self.gethostaddr()
        print "MDNS brodcasted service address :"+ip
        self.ip_32b = socket.inet_aton(ip)

        self.server.registerService(
             Zeroconf.ServiceInfo(self.service_type,
                                  self.service_name,
                                  self.ip_32b,
                                  self.port,
                                  properties = self.serviceproperties))
        self.retrytimer=None
    
    def UnRegisterService(self):
        if self.retrytimer is not None:
            self.retrytimer.cancel()

        self.server.unregisterService(
                                      Zeroconf.ServiceInfo(self.service_type, 
                                                           self.service_name, 
                                                           self.ip_32b, 
                                                           self.port, 
                                                           properties = self.serviceproperties))
        self.server.close()
        self.server = None
    
    def gethostaddr(self, dst = '224.0.1.41'):
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        try:
            s.connect((dst, 7))
            (host, port) = s.getsockname()
            s.close()
            if host != '0.0.0.0':
                return host
        except Exception,e:
            pass
        return socket.gethostbyname(socket.gethostname())