# -*- test-case-name: wokkel.test.test_generic -*-
#
# Copyright (c) 2003-2008 Ralph Meijer
# See LICENSE for details.

"""
Generic XMPP protocol helpers.
"""

from zope.interface import implements

from twisted.internet import defer
from twisted.words.protocols.jabber import error
from twisted.words.protocols.jabber.xmlstream import toResponse
from twisted.words.xish import domish

from wokkel import disco
from wokkel.iwokkel import IDisco
from wokkel.subprotocols import XMPPHandler

IQ_GET = '/iq[@type="get"]'
IQ_SET = '/iq[@type="set"]'

NS_VERSION = 'jabber:iq:version'
VERSION = IQ_GET + '/query[@xmlns="' + NS_VERSION + '"]'

def parseXml(string):
    """
    Parse serialized XML into a DOM structure.

    @param string: The serialized XML to be parsed, UTF-8 encoded.
    @type string: C{str}.
    @return: The DOM structure, or C{None} on empty or incomplete input.
    @rtype: L{domish.Element}
    """
    roots = []
    results = []
    elementStream = domish.elementStream()
    elementStream.DocumentStartEvent = roots.append
    elementStream.ElementEvent = lambda elem: roots[0].addChild(elem)
    elementStream.DocumentEndEvent = lambda: results.append(roots[0])
    elementStream.parse(string)
    return results and results[0] or None



def stripNamespace(rootElement):
    namespace = rootElement.uri

    def strip(element):
        if element.uri == namespace:
            element.uri = None
            if element.defaultUri == namespace:
                element.defaultUri = None
            for child in element.elements():
                strip(child)

    if namespace is not None:
        strip(rootElement)

    return rootElement



class FallbackHandler(XMPPHandler):
    """
    XMPP subprotocol handler that catches unhandled iq requests.

    Unhandled iq requests are replied to with a service-unavailable stanza
    error.
    """

    def connectionInitialized(self):
        self.xmlstream.addObserver(IQ_SET, self.iqFallback, -1)
        self.xmlstream.addObserver(IQ_GET, self.iqFallback, -1)

    def iqFallback(self, iq):
        if iq.handled == True:
            return

        reply = error.StanzaError('service-unavailable')
        self.xmlstream.send(reply.toResponse(iq))



class VersionHandler(XMPPHandler):
    """
    XMPP subprotocol handler for XMPP Software Version.

    This protocol is described in
    U{XEP-0092<http://www.xmpp.org/extensions/xep-0092.html>}.
    """

    implements(IDisco)

    def __init__(self, name, version):
        self.name = name
        self.version = version

    def connectionInitialized(self):
        self.xmlstream.addObserver(VERSION, self.onVersion)

    def onVersion(self, iq):
        response = toResponse(iq, "result")

        query = response.addElement((NS_VERSION, "query"))
        name = query.addElement("name", content=self.name)
        version = query.addElement("version", content=self.version)
        self.send(response)

        iq.handled = True

    def getDiscoInfo(self, requestor, target, node):
        info = set()

        if not node:
            info.add(disco.DiscoFeature(NS_VERSION))

        return defer.succeed(info)

    def getDiscoItems(self, requestor, target, node):
        return defer.succeed([])