#!/usr/bin/python
#
# Copyright Martin Owens, 2011
#
# 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 3 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, see <http://www.gnu.org/licenses/>
#
"""
Attempt to connect to the GDM2 greeter dbus service.

This python attempts to replace the greeter with an experimental
replacement, to show it's possible.

No user listing yet.
"""

USERNAME = "Your USERNAME here"
PASSWORD = "Your PASSWORD here"

import os
import sys
import gobject

import dbus
import dbus.bus
import dbus.exceptions
import dbus.mainloop.glib

sys.stderr.write("Experimental Greeter Started\n")
dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
mainloop = gobject.MainLoop()

class GdmDbusService(object):
    """Basic wrapper to create the correct interfaces and proxy signals"""
    def __init__(self):
        try:
            # The first is access to the object and any interfaces.
            self.raw = self.connection.get_object(self.address, self.path)
        except dbus.exceptions.DBusException:
            sys.stderr.write("Failed to get Dbus object %s\n" % self.path)
            raise
        # The second is access to the interface, which is more interesting.
        self.obj = dbus.Interface(self.raw, self.interface)
        # Watch all signals on this interface
        self.connection.add_signal_receiver(self.got_signal,
            dbus_interface=self.interface, signal_name=None, bus_name=None, path=self.path,
            sender_keyword="sent", destination_keyword="dest", interface_keyword=None,
            member_keyword="name", path_keyword=None, message_keyword=None
        )

    def got_signal(self, *args, **kwargs):
        """Log all signals and call the proxy method for it."""
        name = kwargs.pop('name', 'Unknown')
        # Call the object's signal proxy method
        if hasattr(self, name):
            getattr(self, name)( *args )
        else:
            for key in kwargs.keys():
                if kwargs[key] == None:
                    kwargs.pop(key)
            if kwargs:
                sys.stderr.write( "%s:%s%s %s\n" % (
                    self.interface, name, str(args), str(kwargs)) )
            else:
                sys.stderr.write("%s:%s%s\n" % (self.interface, name, str(args)))


class GdmGreeter(GdmDbusService):
    """Connects tot he greeter client"""
    path = '/org/gnome/DisplayManager/GreeterServer'
    address = 'org.gnome.DisplayManager.GreeterServer'
    interface = 'org.gnome.DisplayManager.GreeterServer'

    def __init__(self, address):
        try:
            self.connection = dbus.connection.Connection(address)
            sys.stderr.write("Connected to Greeter-Service on %s\n" % address)
        except dbus.exceptions.DBusException:
            sys.stderr.write("Failed to connect to Greeter-Service on %s\n" % address)
            raise
        super(GdmGreeter, self).__init__()
        self.display = GdmDisplay(self.obj.GetDisplayId())

    def Ready(self):
        """Called when greeter service is ready"""
        sys.stderr.write("Server is Ready\n")
        # Will signal InfoQuery for Username first, then password
        #self.obj.BeginVerification()
        # Will signal SecrateInfoQuery for Password only
        self.obj.BeginVerificationForUser(USERNAME)

    def InfoQuery(self, text):
        """Server wants to ask the user for something"""
        sys.stderr.write("Asking user for '%s'\n" % text)
        # XXX We don't do anything

    def SecretInfoQuery(self, text):
        """Server wants to ask for some secrate info"""
        sys.stderr.write("Secrate request for '%s'\n" % text)
        self.obj.AnswerQuery(PASSWORD)

    def UserAuthorized(self):
        """User is ready to go, lets get them in"""
        self.obj.StartSessionWhenReady( True )
        sys.exit(0)


class GdmDisplay(GdmDbusService):
    """Connect to the display bus"""
    address = 'org.gnome.DisplayManager'
    interface = 'org.gnome.DisplayManager.Display'

    def __init__(self, path):
        self.connection = dbus.SystemBus()
        self.path = path
        super(GdmDisplay, self).__init__()


# Start the client using the address for the private dbus
greeter = GdmGreeter(os.environ['GDM_GREETER_DBUS_ADDRESS'])
mainloop.run()