new file mode 100644
--- /dev/null
+++ b/bridge.py
@@ -0,0 +1,175 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# 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/>.
+
+
+import muc
+xmpp = muc.xmpp
+del muc
+from participant import *
+from encoding import *
+
+
+class NoSuchParticipantException(Exception): pass
+
+
+class bridge:
+	def __init__(self, owner_bot, xmpp_room_jid, irc_room, irc_server, irc_port=6667, mode='normal'):
+		self.bot = owner_bot
+		self.irc_server = irc_server
+		self.irc_port = irc_port
+		self.irc_room = irc_room
+		self.participants = []
+		self.mode = mode
+		
+		# Join IRC room
+		self.irc_connection = self.bot.irc.server()
+		self.irc_connection.nick_callback = self._irc_nick_callback
+		self.irc_connection.bridge = self
+		try:
+			self.irc_connection.connect(irc_server, irc_port, self.bot.nickname)
+		except:
+			self.bot.error('Error: joining IRC room failed')
+			raise
+		
+		# Join XMPP room
+		try:
+			self.xmpp_room = xmpp.muc(xmpp_room_jid)
+			self.xmpp_room.join(self.bot.xmpp_c, self.bot.nickname)
+		except:
+			self.bot.error('Error: joining XMPP room failed')
+			raise
+	
+	
+	def _irc_nick_callback(self, error):
+		if error == None:
+			self.irc_connection.join(self.irc_room)
+			self.irc_connection.nick_callback = None
+			self.bot.error('===> Debug: successfully connected on IRC side of bridge "'+str(self)+'"', debug=True)
+		elif self.protocol != 'both':
+			if error == 'nicknameinuse':
+				self.bot.error('Error: "'+self.bot.nickname+'" is already used in the IRC chan of bridge "'+str(self)+'"')
+				raise Exception('Error: "'+self.bot.nickname+'" is already used in the IRC chan of bridge "'+str(self)+'"')
+			elif error == 'erroneusnickname':
+				self.bot.error('Error: "'+self.bot.nickname+'" got "erroneusnickname" on bridge "'+str(self)+'"')
+				raise Exception('Error: "'+self.bot.nickname+'" got "erroneusnickname" on bridge "'+str(self)+'"')
+	
+	
+	def addParticipant(self, protocol, nickname):
+		"""Add a participant to the bridge."""
+		if (protocol == 'irc' and nickname == self.irc_connection.get_nickname()) or (protocol == 'xmpp' and nickname == self.xmpp_room.nickname):
+			raise Exception('cannot add self')
+		try:
+			p = self.getParticipant(nickname)
+			if p.protocol != protocol:
+				if protocol == 'irc':
+					p.createDuplicateOnXMPP()
+				elif protocol == 'xmpp':
+					p.createDuplicateOnIRC()
+				else:
+					raise Exception('Internal Error: bad protocol')
+			return
+		except NoSuchParticipantException:
+			pass
+		self.bot.error('===> Debug: adding participant "'+nickname+'" from "'+protocol+'" to bridge "'+str(self)+'"', debug=True)
+		p = participant(self, protocol, nickname)
+		self.participants.append(p)
+		return p
+	
+	
+	def getParticipant(self, nickname):
+		"""Returns a participant object if there is a participant using nickname in the bridge. Raises a NoSuchParticipantException otherwise."""
+		for participant_ in self.participants:
+			if participant_.nickname == nickname:
+				return participant_
+		raise NoSuchParticipantException('there is no participant using the nickname "'+nickname+'" in this bridge')
+	
+	
+	def removeParticipant(self, protocol, nickname, leave_message):
+		"""Remove the participant using nickname from the bridge. Raises a NoSuchParticipantException if nickname is not used in the bridge."""
+		p = self.getParticipant(nickname)
+		if p.protocol == 'both':
+			self.bot.error('===> Debug: "'+nickname+'" was on both sides of bridge "'+str(self)+'" but left '+protocol, debug=True)
+			if protocol == 'xmpp':
+				p.createDuplicateOnIRC()
+			elif protocol == 'irc':
+				p.createDuplicateOnXMPP()
+			else:
+				raise Exception('Internal Error: bad protocol')
+		else:
+			self.bot.error('===> Debug: removing participant "'+nickname+'" from bridge "'+str(self)+'"', debug=True)
+			self.participants.remove(p)
+			p.leave(leave_message)
+			i = 0
+			for p in self.participants:
+				if p.protocol == 'irc':
+					i += 1
+			if protocol == 'xmpp' and self.irc_connections_limit >= i:
+				self.switchToNormalMode()
+			del p
+	
+	
+	def say(self, message):
+		self.xmpp_room.say(message)
+		self.irc_connection.privmsg(self.irc_room, auto_encode(message))
+	
+	
+	def switchToNormalMode(self):
+		if self.mode == 'normal':
+			return
+		prev_mode = self.mode
+		self.mode = 'normal'
+		for p in self.participants:
+			if p.protocol == 'xmpp':
+				p.createDuplicateOnIRC()
+			elif p.protocol == 'irc' and prev_mode == 'minimal':
+				p.createDuplicateOnXMPP()
+		self.bot.error('===> Bridge is switching to normal mode.')
+		self.say('[Notice] Bridge is switching to normal mode.')
+	
+	
+	def switchToLimitedMode(self):
+		if self.mode == 'limited':
+			return
+		self.mode = 'limited'
+		i = 0
+		for p in self.participants:
+			if p.protocol == 'xmpp':
+				i += 1
+				if p.irc_connection:
+					p.irc_connection.disconnect('Bridge is switching to limited mode')
+					p.irc_connection.close()
+					p.irc_connection = None
+		self.irc_connections_limit = i
+		self.bot.error('===> Bridge is switching to limited mode.')
+		self.say('[Warning] Bridge is switching to limited mode, it means that it will be transparent for XMPP users but not for IRC users, this is due to the IRC servers\' per-IP-address connections\' limit number.')
+	
+	
+	def __str__(self):
+		return self.irc_room+'@'+self.irc_server+' <-> '+self.xmpp_room.room_jid
+	
+	
+	def __del__(self):
+		# Delete participants objects
+		for p in self.participants:
+			p.leave('Removing bridge')
+			del p
+		# Leave IRC room
+		self.irc_connection.quit('Removing bridge')
+		# Close IRC connection
+		self.irc_connection.close()
+		del self.irc_connection
+		# Leave XMPP room
+		self.xmpp_room.leave('Removing bridge')
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