#!/usr/bin/env python

from mercurial import hg
from mercurial import commands

import dbus
import gobject
import avahi
from dbus.mainloop.glib import DBusGMainLoop

class AvahiReg:

	def __init__(self, name, port):
		self.verbose = False
		self.serviceName = "Mercurial"
		if name != '':
			self.serviceName += ": " + name
		self.serviceType = "_http._tcp" # See http://www.dns-sd.org/ServiceTypes.html
		self.servicePort = port
		self.serviceTXT = ["extension's author=Alessio Caiazza"] #TXT record for the service

		self.domain = "" # Domain to publish on, default to .local
		self.host = "" # Host to publish records for, default to localhost

		self.group = None #our entry group
		self.rename_count = 12 # Counter so we only rename after collisions a sensible number of times

	def add_service(self):
		if self.group is None:
			self.group = dbus.Interface(
				self.bus.get_object( avahi.DBUS_NAME, self.server.EntryGroupNew()),
				avahi.DBUS_INTERFACE_ENTRY_GROUP)
			self.group.connect_to_signal('StateChanged', self.entry_group_state_changed)
		if self.verbose:
			print "Adding service '%s' of type '%s' ..." % (self.serviceName, self.serviceType)
		self.group.AddService(
			avahi.IF_UNSPEC,    #interface
			avahi.PROTO_UNSPEC, #protocol
			0,                  #flags
			self.serviceName, self.serviceType,
			self.domain, self.host,
			dbus.UInt16(self.servicePort),
			avahi.string_array_to_txt_array(self.serviceTXT))
		self.group.Commit()

	def remove_service(self):
		if not group is None:
			group.Reset()

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

	def entry_group_state_changed(self,state, error):

		if self.verbose:
			print "state change: %i" % state

		if state == avahi.ENTRY_GROUP_ESTABLISHED:
			print "Service established."
		elif state == avahi.ENTRY_GROUP_COLLISION:

			rename_count = rename_count - 1
			if rename_count > 0:
				name = server.GetAlternativeServiceName(name)
				if self.verbose:
					print "WARNING: Service name collision, changing name to '%s' ..." % name
				remove_service()
				add_service()

			else:
				if self.verbose:
					print "ERROR: No suitable service name found after %i retries, exiting." % n_rename
				main_loop.quit()
		elif state == avahi.ENTRY_GROUP_FAILURE:
			if self.verbose:
				print "Error in group state changed", error
			main_loop.quit()
			return

	def start(self):
		DBusGMainLoop( set_as_default=True )
		self.bus = dbus.SystemBus()

		self.server = dbus.Interface(
			self.bus.get_object( avahi.DBUS_NAME, avahi.DBUS_PATH_SERVER ),
			avahi.DBUS_INTERFACE_SERVER )

		self.server.connect_to_signal( "StateChanged", self.server_state_changed )
		self.server_state_changed( self.server.GetState() )
	
	def stop(self):
		if self.verbose:
			print "Stopping avahi-publish-service"
		if not self.group is None:
			self.group.Free()

# every command must take a ui and and repo as arguments.
# opts is a dict where you can find other command line flags
#
# Other parameters are taken in order from items on the command line that
# don't start with a dash.  If no default value is given in the parameter list,
# they are required.
def avahi_serve(ui, repo, **opts):
	# The doc string below will show up in hg help
	"""Serve and publish on avahi zeroconf"""

	#print opts
	if opts['port'] != 0:
		port = int(opts['port'])
	else:
		port = 8000
	a = AvahiReg(opts['name'], port)

	if ui.cdata.has_option('web', 'description'):
		a.serviceTXT += ["description=" + ui.cdata.get('web','description')]
	if ui.cdata.has_option('ui', 'username'):
		#remove < and > cose make problems on Avahi Discovery
		a.serviceTXT += ["owner=" + 
				ui.cdata.get('ui','username')
				.replace('<','')
				.replace('>','')]

	a.verbose = ui.verbose
	a.start()
	try:
		commands.serve(ui,repo, **opts)
	except KeyboardInterrupt:
		pass
	
	a.stop()

cmdtable = {
	# cmd name        function call
	"aserve": (avahi_serve,
		commands.table['^serve'][1],
		"hg aserve [OPTION]...")
}