#!/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 program 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
# of the License, or (at your option) any later version.
#
# This program 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 program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.


from __future__ import absolute_import
from __future__ import print_function
import traceback
from time import sleep
import copy
import socket
import os.path

import Pyro
import Pyro.core
import Pyro.util
from Pyro.errors import PyroError

import PSKManagement as PSK
from runtime import PlcStatus

zeroconf_service_type = '_PYRO._tcp.local.'
# this module attribute contains a list of DNS-SD (Zeroconf) service types
# supported by this connector confnode.
#
# for connectors that do not support DNS-SD, this attribute can be omitted
# or set to an empty list.


def PYRO_connector_factory(uri, confnodesroot):
    """
    This returns the connector to Pyro style PLCobject
    """
    confnodesroot.logger.write(_("PYRO connecting to URI : %s\n") % uri)

    scheme, location = uri.split("://")
    if scheme == "PYROS":
        import connectors.PYRO.PSK_Adapter
        schemename = "PYROLOCPSK"
        url, ID = location.split('#') #TODO fix exception when # not found
        # load PSK from project
        secpath = os.path.join(str(confnodesroot.ProjectPath), 'psk', ID+'.secret')
        if not os.path.exists(secpath):
            confnodesroot.logger.write_error(
                'Error: Pre-Shared-Key Secret in %s is missing!\n' % secpath)
            return None
        secret = open(secpath).read().partition(':')[2].rstrip('\n\r')
        Pyro.config.PYROPSK = (secret, ID)
        # strip ID from URL, so that pyro can understand it.
        location = url
    else:
        schemename = "PYROLOC"

    if location.find(zeroconf_service_type) != -1:
        try:
            from zeroconf import Zeroconf
            r = Zeroconf()
            i = r.get_service_info(zeroconf_service_type, location)
            if i is None:
                raise Exception("'%s' not found" % location)
            ip = str(socket.inet_ntoa(i.address))
            port = str(i.port)
            newlocation = ip + ':' + port
            confnodesroot.logger.write(_("'{a1}' is located at {a2}\n").format(a1=location, a2=newlocation))
            location = newlocation
            r.close()
        except Exception:
            confnodesroot.logger.write_error(_("MDNS resolution failure for '%s'\n") % location)
            confnodesroot.logger.write_error(traceback.format_exc())
            return None

    # Try to get the proxy object
    try:
        RemotePLCObjectProxy = Pyro.core.getAttrProxyForURI(schemename + "://" + location + "/PLCObject")
    except Exception:
        confnodesroot.logger.write_error(_("Connection to '%s' failed with exception '%s'\n") % (location, str(e)))
        #confnodesroot.logger.write_error(traceback.format_exc())
        return None

    RemotePLCObjectProxy.adapter.setTimeout(60)

    def PyroCatcher(func, default=None):
        """
        A function that catch a Pyro exceptions, write error to logger
        and return default value when it happen
        """
        def catcher_func(*args, **kwargs):
            try:
                return func(*args, **kwargs)
            except Pyro.errors.ConnectionClosedError as e:
                confnodesroot.logger.write_error(_("Connection lost!\n"))
                confnodesroot._SetConnector(None)
            except Pyro.errors.ProtocolError as e:
                confnodesroot.logger.write_error(_("Pyro exception: %s\n") % e)
            except Exception as e:
                # confnodesroot.logger.write_error(traceback.format_exc())
                errmess = ''.join(Pyro.util.getPyroTraceback(e))
                confnodesroot.logger.write_error(errmess + "\n")
                print(errmess)
                confnodesroot._SetConnector(None)
            return default
        return catcher_func

    # Check connection is effective.
    # lambda is for getattr of GetPLCstatus to happen inside catcher
    IDPSK = PyroCatcher(RemotePLCObjectProxy.GetPLCID)()
    if IDPSK is None:
        confnodesroot.logger.write_warning(_("PLC did not provide identity and security infomation.\n"))
    else:
        ID,secret = IDPSK
        PSK.UpdateID(confnodesroot.ProjectPath, ID, secret, uri)


    _special_return_funcs = {
        "StartPLC": False,
        "GetTraceVariables": (PlcStatus.Broken, None),
        "GetPLCstatus": (PlcStatus.Broken, None),
        "RemoteExec": (-1, "RemoteExec script failed!")
    }

    class PyroProxyProxy(object):
        """
        A proxy proxy class to handle Beremiz Pyro interface specific behavior.
        And to put Pyro exception catcher in between caller and Pyro proxy
        """
        def __getattr__(self, attrName):
            member = self.__dict__.get(attrName, None)
            if member is None:
                def my_local_func(*args, **kwargs):
                    return RemotePLCObjectProxy.__getattr__(attrName)(*args, **kwargs)
                member = PyroCatcher(my_local_func, _special_return_funcs.get(attrName, None))
                self.__dict__[attrName] = member
            return member

    return PyroProxyProxy