#!/usr/bin/python

import logging
import os
import string
import subprocess

try:
    import glib
    import gobject
    import dbus
    import dbus.service
    import dbus.mainloop.glib
except ImportError, e:
    sys.stderr.write("Failed to import '%s', can not use dbus" % e)
    sys.exit(1)

class PermissionDeniedError(dbus.DBusException):
    " permission denied by policy "
    pass

class AptXapianIndexDBusService(dbus.service.Object): 
    DBUS_INTERFACE_NAME = "org.debian.AptXapianIndex"

    def __init__(self):
        bus_name = dbus.service.BusName(self.DBUS_INTERFACE_NAME,
                                        bus=dbus.SystemBus())
        dbus.service.Object.__init__(self, bus_name, '/')
        self._active_axi = None

    def _authWithPolicyKit(self, sender, connection, priv):
        system_bus = dbus.SystemBus()
        obj = system_bus.get_object("org.freedesktop.PolicyKit1", 
                                    "/org/freedesktop/PolicyKit1/Authority", 
                                    "org.freedesktop.PolicyKit1.Authority")
        policykit = dbus.Interface(obj, "org.freedesktop.PolicyKit1.Authority")
        info = dbus.Interface(connection.get_object('org.freedesktop.DBus',
                                              '/org/freedesktop/DBus/Bus', 
                                              False), 
                              'org.freedesktop.DBus')
        pid = info.GetConnectionUnixProcessID(sender) 
        subject = ('unix-process', 
                   { 'pid' : dbus.UInt32(pid, variant_level=1),
                     'start-time' : dbus.UInt64(0, variant_level=1),
                   }
                  )
        details = { '' : '' }
        flags = dbus.UInt32(1) #   AllowUserInteraction = 0x00000001
        cancel_id = ''
        (ok, notused, details) = policykit.CheckAuthorization(
            subject, priv, details, flags, cancel_id)
        return ok

    @dbus.service.signal(dbus_interface=DBUS_INTERFACE_NAME,
                         signature="b")
    def UpdateFinished(self, res):
        logging.debug("Emitting UpdateFinished: %s" % res)

    @dbus.service.signal(dbus_interface=DBUS_INTERFACE_NAME,
                         signature="i")
    def UpdateProgress(self, percent):
        logging.debug("Emitting UpdateProgress: %s" % percent)

    def _update_apt_xapian_index(self, cmd):
        p = subprocess.Popen(cmd, stdout=subprocess.PIPE)
        self._active_axi = p
        while True:
            while gobject.main_context_default().pending():
                 gobject.main_context_default().iteration()
            res = p.poll()
            if res is not None:
                break
            line = p.stdout.readline().strip()
            if not line:
                continue
            try:
                (op, progress) = string.split(line, sep=":", maxsplit=1)
                if op == "progress":
                    percent = int(progress.split("/")[0])
                    self.UpdateProgress(percent)
            except ValueError:
                pass
        # axi finished
        self._active_axi = None
        # emit finish signal
        self.UpdateFinished(res == 0)

    @dbus.service.method(DBUS_INTERFACE_NAME,
                         in_signature='bb', 
                         out_signature='',
                         sender_keyword='sender',
                         connection_keyword='conn')
    def update_async(self, force, update_only, sender=None, conn=None):
        if not self._authWithPolicyKit(sender, conn, 
                                       "org.debian.aptxapianindex.update"):
            raise PermissionDeniedError, "Permission denied by policy"
        # do not start update-apt-xapian-index twice, the clients will
        # get the finished signal from the previous running one
        if self._active_axi:
            return
        cmd = ["/usr/sbin/update-apt-xapian-index", "--batch-mode"]
        if force:
            cmd.append("--force")
        if update_only:
            cmd.append("--update")
        glib.timeout_add(100, self._update_apt_xapian_index, cmd)

if __name__ == "__main__":
    dbus.mainloop.glib.DBusGMainLoop(set_as_default=True) 
    server = AptXapianIndexDBusService()
    gobject.MainLoop().run()