##   transports.py
##
##   Copyright (C) 2003-2005 Alexey "Snake" Nezhdanov
##
##   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 2, 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.

# $Id: dispatcher.py,v 1.42 2007/05/18 23:18:36 normanr Exp $

"""
Main xmpppy mechanism. Provides library with methods to assign different handlers
to different XMPP stanzas.
Contains one tunable attribute: DefaultTimeout (25 seconds by default). It defines time that
Dispatcher.SendAndWaitForResponce method will wait for reply stanza before giving up.
"""

import time,sys
from . import simplexml
from .protocol import *
from .client import PlugIn

DefaultTimeout=25
ID=0

class Dispatcher(PlugIn):
	""" Ancestor of PlugIn class. Handles XMPP stream, i.e. aware of stream headers.
		Can be plugged out/in to restart these headers (used for SASL f.e.). """
	def __init__(self):
		PlugIn.__init__(self)
		DBG_LINE='dispatcher'
		self.handlers={}
		self._expected={}
		self._defaultHandler=None
		self._pendingExceptions=[]
		self._eventHandler=None
		self._cycleHandlers=[]
		self._exported_methods=[self.Process,self.RegisterHandler,self.RegisterDefaultHandler,\
		self.RegisterEventHandler,self.UnregisterCycleHandler,self.RegisterCycleHandler,\
		self.RegisterHandlerOnce,self.UnregisterHandler,self.RegisterProtocol,\
		self.WaitForResponse,self.SendAndWaitForResponse,self.send,self.disconnect,\
		self.SendAndCallForResponse, ]

	def dumpHandlers(self):
		""" Return set of user-registered callbacks in it's internal format.
			Used within the library to carry user handlers set over Dispatcher replugins. """
		return self.handlers
	def restoreHandlers(self,handlers):
		""" Restores user-registered callbacks structure from dump previously obtained via dumpHandlers.
			Used within the library to carry user handlers set over Dispatcher replugins. """
		self.handlers=handlers

	def _init(self):
		""" Registers default namespaces/protocols/handlers. Used internally.  """
		self.RegisterNamespace('unknown')
		self.RegisterNamespace(NS_STREAMS)
		self.RegisterNamespace(self._owner.defaultNamespace)
		self.RegisterProtocol('iq',Iq)
		self.RegisterProtocol('presence',Presence)
		self.RegisterProtocol('message',Message)
		self.RegisterDefaultHandler(self.returnStanzaHandler)
		self.RegisterHandler('error',self.streamErrorHandler,xmlns=NS_STREAMS)

	def plugin(self, owner):
		""" Plug the Dispatcher instance into Client class instance and send initial stream header. Used internally."""
		self._init()
		for method in self._old_owners_methods:
			if method.__name__=='send': self._owner_send=method; break
		self._owner.lastErrNode=None
		self._owner.lastErr=None
		self._owner.lastErrCode=None
		self.StreamInit()

	def plugout(self):
		""" Prepares instance to be destructed. """
		self.Stream.dispatch=None
		self.Stream.DEBUG=None
		self.Stream.features=None
		self.Stream.destroy()

	def StreamInit(self):
		""" Send an initial stream header. """
		self.Stream=simplexml.NodeBuilder()
		self.Stream._dispatch_depth=2
		self.Stream.dispatch=self.dispatch
		self.Stream.stream_header_received=self._check_stream_start
		self._owner.debug_flags.append(simplexml.DBG_NODEBUILDER)
		self.Stream.DEBUG=self._owner.DEBUG
		self.Stream.features=None
		self._metastream=Node('stream:stream')
		self._metastream.setNamespace(self._owner.Namespace)
		self._metastream.setAttr('version','1.0')
		self._metastream.setAttr('xmlns:stream',NS_STREAMS)
		self._metastream.setAttr('to',self._owner.Server)
		self._owner.send("<?xml version='1.0'?>%s>"%str(self._metastream)[:-2])

	def _check_stream_start(self,ns,tag,attrs):
		if ns!=NS_STREAMS or tag!='stream':
			raise ValueError('Incorrect stream start: (%s,%s). Terminating.'%(tag,ns))

	def Process(self, timeout=0):
		""" Check incoming stream for data waiting. If "timeout" is positive - block for as max. this time.
			Returns:
			1) length of processed data if some data were processed;
			2) '0' string if no data were processed but link is alive;
			3) 0 (zero) if underlying connection is closed.
			Take note that in case of disconnection detect during Process() call
			disconnect handlers are called automatically.
		"""
		for handler in self._cycleHandlers: handler(self)
		if len(self._pendingExceptions) > 0:
			_pendingException = self._pendingExceptions.pop()
			raise _pendingException[1].with_traceback(_pendingException[2])
		if self._owner.Connection.pending_data(timeout):
			try: data=self._owner.Connection.receive()
			except IOError: return
			self.Stream.Parse(data)
			if len(self._pendingExceptions) > 0:
				_pendingException = self._pendingExceptions.pop()
				raise _pendingException[1].with_traceback(_pendingException[2])
			if data: return len(data)
		return '0'	  # It means that nothing is received but link is alive.

	def RegisterNamespace(self,xmlns,order='info'):
		""" Creates internal structures for newly registered namespace.
			You can register handlers for this namespace afterwards. By default one namespace
			already registered (jabber:client or jabber:component:accept depending on context. """
		self.DEBUG('Registering namespace "%s"'%xmlns,order)
		self.handlers[xmlns]={}
		self.RegisterProtocol('unknown',Protocol,xmlns=xmlns)
		self.RegisterProtocol('default',Protocol,xmlns=xmlns)

	def RegisterProtocol(self,tag_name,Proto,xmlns=None,order='info'):
		""" Used to declare some top-level stanza name to dispatcher.
		   Needed to start registering handlers for such stanzas.
		   Iq, message and presence protocols are registered by default. """
		if not xmlns: xmlns=self._owner.defaultNamespace
		self.DEBUG('Registering protocol "%s" as %s(%s)'%(tag_name,Proto,xmlns), order)
		self.handlers[xmlns][tag_name]={type:Proto, 'default':[]}

	def RegisterNamespaceHandler(self,xmlns,handler,typ='',ns='', makefirst=0, system=0):
		""" Register handler for processing all stanzas for specified namespace. """
		self.RegisterHandler('default', handler, typ, ns, xmlns, makefirst, system)

	def RegisterHandler(self,name,handler,typ='',ns='',xmlns=None, makefirst=0, system=0):
		"""Register user callback as stanzas handler of declared type. Callback must take
		   (if chained, see later) arguments: dispatcher instance (for replying), incomed
		   return of previous handlers.
		   The callback must raise xmpp.NodeProcessed just before return if it want preven
		   callbacks to be called with the same stanza as argument _and_, more importantly
		   library from returning stanza to sender with error set (to be enabled in 0.2 ve
			Arguments:
			  "name" - name of stanza. F.e. "iq".
			  "handler" - user callback.
			  "typ" - value of stanza's "type" attribute. If not specified any value match
			  "ns" - namespace of child that stanza must contain.
			  "chained" - chain together output of several handlers.
			  "makefirst" - insert handler in the beginning of handlers list instead of
				adding it to the end. Note that more common handlers (i.e. w/o "typ" and "
				will be called first nevertheless.
			  "system" - call handler even if NodeProcessed Exception were raised already.
			"""
		if not xmlns: xmlns=self._owner.defaultNamespace
		self.DEBUG('Registering handler %s for "%s" type->%s ns->%s(%s)'%(handler,name,typ,ns,xmlns), 'info')
		if not typ and not ns: typ='default'
		if not (xmlns in self.handlers): self.RegisterNamespace(xmlns,'warn')
		if not name in self.handlers[xmlns]: self.RegisterProtocol(name,Protocol,xmlns,'warn')
		if not typ+ns in self.handlers[xmlns][name]: self.handlers[xmlns][name][typ+ns]=[]
		if makefirst: self.handlers[xmlns][name][typ+ns].insert(0,{'func':handler,'system':system})
		else: self.handlers[xmlns][name][typ+ns].append({'func':handler,'system':system})

	def RegisterHandlerOnce(self,name,handler,typ='',ns='',xmlns=None,makefirst=0, system=0):
		""" Unregister handler after first call (not implemented yet). """
		if not xmlns: xmlns=self._owner.defaultNamespace
		self.RegisterHandler(name, handler, typ, ns, xmlns, makefirst, system)

	def UnregisterHandler(self,name,handler,typ='',ns='',xmlns=None):
		""" Unregister handler. "typ" and "ns" must be specified exactly the same as with registering."""
		if not xmlns: xmlns=self._owner.defaultNamespace
		if not (xmlns in self.handlers): return
		if not typ and not ns: typ='default'
		for pack in self.handlers[xmlns][name][typ+ns]:
			if handler==pack['func']: break
		else: pack=None
		try: self.handlers[xmlns][name][typ+ns].remove(pack)
		except ValueError: pass

	def RegisterDefaultHandler(self,handler):
		""" Specify the handler that will be used if no NodeProcessed exception were raised.
			This is returnStanzaHandler by default. """
		self._defaultHandler=handler

	def RegisterEventHandler(self,handler):
		""" Register handler that will process events. F.e. "FILERECEIVED" event. """
		self._eventHandler=handler

	def returnStanzaHandler(self,conn,stanza):
		""" Return stanza back to the sender with <feature-not-implemennted/> error set. """
		if stanza.getType() in ['get','set']:
			conn.send(Error(stanza,ERR_FEATURE_NOT_IMPLEMENTED))

	def streamErrorHandler(self,conn,error):
		name,text='error',error.getData()
		for tag in error.getChildren():
			if tag.getNamespace()==NS_XMPP_STREAMS:
				if tag.getName()=='text': text=tag.getData()
				else: name=tag.getName()
		if name in stream_exceptions.keys(): exc=stream_exceptions[name]
		else: exc=StreamError
		raise exc((name,text))

	def RegisterCycleHandler(self,handler):
		""" Register handler that will be called on every Dispatcher.Process() call. """
		if handler not in self._cycleHandlers: self._cycleHandlers.append(handler)

	def UnregisterCycleHandler(self,handler):
		""" Unregister handler that will is called on every Dispatcher.Process() call."""
		if handler in self._cycleHandlers: self._cycleHandlers.remove(handler)

	def Event(self,realm,event,data):
		""" Raise some event. Takes three arguments:
			1) "realm" - scope of event. Usually a namespace.
			2) "event" - the event itself. F.e. "SUCESSFULL SEND".
			3) data that comes along with event. Depends on event."""
		if self._eventHandler: self._eventHandler(realm,event,data)

	def dispatch(self,stanza,session=None,direct=0):
		""" Main procedure that performs XMPP stanza recognition and calling apppropriate handlers for it.
			Called internally. """
		if not session: session=self
		session.Stream._mini_dom=None
		
		# bad stanza fixer!
		for tmp in str(stanza).split('><')[1:]:
			if tmp[0] == ' ':
				self.DEBUG("Got bad stanza:\n %s" % str(stanza), 'ok')
				return

		name=stanza.getName()

		if not direct and self._owner._route:
			if name == 'route':
				if stanza.getAttr('error') == None:
					if len(stanza.getChildren()) == 1:
						stanza = stanza.getChildren()[0]
						name=stanza.getName()
					else:
						for each in stanza.getChildren():
							self.dispatch(each,session,direct=1)
						return
			elif name == 'presence':
				return
			elif name in ('features','bind'):
				pass
			else:
				raise UnsupportedStanzaType(name)

		if name=='features': session.Stream.features=stanza

		xmlns=stanza.getNamespace()
		if not (xmlns in self.handlers):
			self.DEBUG("Unknown namespace: " + xmlns,'warn')
			xmlns='unknown'
		if not name in self.handlers[xmlns]:
			self.DEBUG("Unknown stanza: " + name,'warn')
			name='unknown'
		else:
			self.DEBUG("Got %s/%s stanza"%(xmlns,name), 'ok')

		if stanza.__class__.__name__=='Node': stanza=self.handlers[xmlns][name][type](node=stanza)

		typ=stanza.getType()
		if not typ: typ=''
		stanza.props=stanza.getProperties()
		ID=stanza.getID()

		session.DEBUG("Dispatching %s stanza with type->%s props->%s id->%s"%(name,typ,stanza.props,ID),'ok')

		list=['default']													 # we will use all handlers:
		if typ in self.handlers[xmlns][name]: list.append(typ)				# from very common...
		for prop in stanza.props:
			if prop in self.handlers[xmlns][name]: list.append(prop)
			if typ and typ+prop in self.handlers[xmlns][name]: list.append(typ+prop)  # ...to very particular

		chain=self.handlers[xmlns]['default']['default']
		for key in list:
			if key: chain = chain + self.handlers[xmlns][name][key]

		output=''
		if (ID in session._expected):
			user=0
			if type(session._expected[ID])==type(()):
				cb,args=session._expected[ID]
				session.DEBUG("Expected stanza arrived. Callback %s(%s) found!"%(cb,args),'ok')
				try: cb(session,stanza,**args)
				except Exception as typ:
					if typ.__class__.__name__!='NodeProcessed': raise
			else:
				session.DEBUG("Expected stanza arrived!",'ok')
				session._expected[ID]=stanza
		else: user=1
		for handler in chain:
			if user or handler['system']:
				try:
					handler['func'](session,stanza)
				except Exception as typ:
					if typ.__class__.__name__!='NodeProcessed':
						self._pendingExceptions.insert(0, sys.exc_info())
						return
					user=0
		if user and self._defaultHandler: self._defaultHandler(session,stanza)

	def WaitForResponse(self, ID, timeout=DefaultTimeout):
		""" Block and wait until stanza with specific "id" attribute will come.
			If no such stanza is arrived within timeout, return None.
			If operation failed for some reason then owner's attributes
			lastErrNode, lastErr and lastErrCode are set accordingly. """
		self._expected[ID]=None
		has_timed_out=0
		abort_time=time.time() + timeout
		self.DEBUG("Waiting for ID:%s with timeout %s..." % (ID,timeout),'wait')
		while not self._expected[ID]:
			if not self.Process(0.04):
				self._owner.lastErr="Disconnect"
				return None
			if time.time() > abort_time:
				self._owner.lastErr="Timeout"
				return None
		response=self._expected[ID]
		del self._expected[ID]
		if response.getErrorCode():
			self._owner.lastErrNode=response
			self._owner.lastErr=response.getError()
			self._owner.lastErrCode=response.getErrorCode()
		return response

	def SendAndWaitForResponse(self, stanza, timeout=DefaultTimeout):
		""" Put stanza on the wire and wait for recipient's response to it. """
		return self.WaitForResponse(self.send(stanza),timeout)

	def SendAndCallForResponse(self, stanza, func, args={}):
		""" Put stanza on the wire and call back when recipient replies.
			Additional callback arguments can be specified in args. """
		self._expected[self.send(stanza)]=(func,args)

	def send(self,stanza):
		""" Serialise stanza and put it on the wire. Assign an unique ID to it before send.
			Returns assigned ID."""
		if type(stanza) in [type(''), type(u'')]: return self._owner_send(stanza)
		if not isinstance(stanza,Protocol): _ID=None
		elif not stanza.getID():
			global ID
			ID+=1
			_ID=repr(ID)
			stanza.setID(_ID)
		else: _ID=stanza.getID()
		if self._owner._registered_name and not stanza.getAttr('from'): stanza.setAttr('from',self._owner._registered_name)
		if self._owner._route and stanza.getName()!='bind':
			to=self._owner.Server
			if stanza.getTo() and stanza.getTo().getDomain():
				to=stanza.getTo().getDomain()
			frm=stanza.getFrom()
			if frm.getDomain():
				frm=frm.getDomain()
			route=Protocol('route',to=to,frm=frm,payload=[stanza])
			stanza=route
		stanza.setNamespace(self._owner.Namespace)
		stanza.setParent(self._metastream)
		self._owner_send(stanza)
		return _ID

	def disconnect(self):
		""" Send a stream terminator and and handle all incoming stanzas before stream closure. """
		self._owner_send('</stream:stream>')
		while self.Process(1): pass