#!/usr/bin/python2.4
# -*-python-*-
# $Id$

import avahi, dbus, gobject, sys, getopt

try:
    import dbus.glib
except ImportError, e:
    pass

def usage(retval = 0):
    print "%s [options] <name> <type> <port> [<txt> ...]\n" % sys.argv[0]
    print "   -h --help      Show this help"
    print "   -d --domain    Domain where to register this service"
    print "   -H --host      Host where this service resides"
    sys.exit(retval)

try:
    opts, args = getopt.getopt(sys.argv[1:], "d:H:", ["help", "domain=", "host="])
except getopt.GetoptError:
    usage(2)

domain = ""
host = ""
    
for o, a in opts:
    if o in ("-h", "--help"):
        usage()

    if o in ("-d", "--domain"):
        domain = a

    if o in ("-H", "--host"):
        host = a

if len(args) < 3:
    sys.stderr.write("Invalid number of arguments\n")
    sys.exit(1)

name = args[0]
stype = args[1]
port = int(args[2])
txt = args[3:]

# python-dbus doesn't allow transmission of empty arrays, therefore we "fix" it with a bogus entry
if len(txt) == 0:
    txt.append("python-dbus=brain-damage")

group = None
n_rename = 0

def remove_service():
    global group

    if not (group is None):
        group.Free()
        group = None

def add_service():
    global server, group, name, stype, domain, host, port, txt
    assert group is None

    print "Adding service '%s' of type '%s' ..." % (name, stype)
    group = dbus.Interface(bus.get_object(avahi.DBUS_NAME, server.EntryGroupNew()), avahi.DBUS_INTERFACE_ENTRY_GROUP)
    group.connect_to_signal('StateChanged', entry_group_state_changed)
    group.AddService(avahi.IF_UNSPEC, avahi.PROTO_UNSPEC, name, stype, domain, host, dbus.UInt16(port), txt)
    group.Commit()

def entry_group_state_changed(state):
    global name, server, n_rename
    
    if state == avahi.ENTRY_GROUP_ESTABLISHED:
        print "Service established."
    elif state == avahi.ENTRY_GROUP_COLLISION:

        n_rename = n_rename + 1
        if n_rename >= 12:
            print "ERROR: No suitable service name found after %i retries, exiting." % n_rename
            main_loop.quit()
        else:
            name = server.GetAlternativeServiceName(name)
            print "WARNING: Service name collision, changing name to '%s' ..." % name
            remove_service()
            add_service()

def server_state_changed(state):
    if state == avahi.SERVER_COLLISION:
        print "WARNING: Server name collision"
        remove_service()
    elif state == avahi.SERVER_RUNNING:
        add_service()

main_loop = gobject.MainLoop()

bus = dbus.SystemBus()
server = dbus.Interface(bus.get_object(avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER), avahi.DBUS_INTERFACE_SERVER)
server.connect_to_signal("StateChanged", server_state_changed)
server_state_changed(server.GetState())

try:
    main_loop.run()
except KeyboardInterrupt, k:
    pass

remove_service()