# -*- coding: utf-8 -*-
# -*- test-case-name: wokkel.test.test_mam -*-
#
# SàT Wokkel extension for Message Archive Management (XEP-0313)
# Copyright (C) 2015 Adien Cossa (souliane@mailoo.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Copyright (c) Adrien Cossa.
# See LICENSE for details.

"""
XMPP Message Archive Management protocol.

This protocol is specified in
U{XEP-0313<http://xmpp.org/extensions/xep-0313.html>}.
"""

from dateutil.tz import tzutc

from zope.interface import Interface, implements

from twisted.words.protocols.jabber.xmlstream import IQ, toResponse
from twisted.words.xish import domish
from twisted.words.protocols.jabber import jid
from twisted.python import log

from wokkel.subprotocols import IQHandlerMixin, XMPPHandler
from wokkel import disco, data_form, delay

import rsm

NS_MAM = 'urn:xmpp:mam:0'
NS_FORWARD = 'urn:xmpp:forward:0'

FIELDS_REQUEST = "/iq[@type='get']/query[@xmlns='%s']" % NS_MAM
ARCHIVE_REQUEST = "/iq[@type='set']/query[@xmlns='%s']" % NS_MAM
PREFS_GET_REQUEST = "/iq[@type='get']/prefs[@xmlns='%s']" % NS_MAM
PREFS_SET_REQUEST = "/iq[@type='set']/prefs[@xmlns='%s']" % NS_MAM

# TODO: add the tests!


class MAMError(Exception):
    """
    MAM error.
    """


class Unsupported(MAMError):
    def __init__(self, feature, text=None):
        self.feature = feature
        MAMError.__init__(self, 'feature-not-implemented',
                                'unsupported',
                                feature,
                                text)

    def __str__(self):
        message = MAMError.__str__(self)
        message += ', feature %r' % self.feature
        return message


class MAMQueryRequest():
    """
    A Message Archive Management <query/> request.

    @ivar form: Data Form specifing the filters.
    @itype form: L{data_form.Form}

    @ivar rsm: RSM request instance.
    @itype rsm: L{rsm.RSMRequest}

    @ivar node: pubsub node id if querying a pubsub node, else None.
    @itype form: C{unicode}
    """

    def __init__(self, form=None, rsm_=None, node=None):
        if form is not None:
            assert form.formType == 'submit'
        self.form = form
        self.rsm = rsm_
        self.node = node

    @classmethod
    def parse(cls, element):
        """Parse the DOM representation of a MAM <query/> request.

        @param element: MAM <query/> request element.
        @type element: L{Element<twisted.words.xish.domish.Element>}

        @return: MAMQueryRequest instance.
        @rtype: L{MAMQueryRequest}
        """
        if element.uri != NS_MAM or element.name != 'query':
            raise MAMError('Element provided is not a MAM <query/> request')
        form = data_form.findForm(element, NS_MAM)
        try:
            rsm_request = rsm.RSMRequest.parse(element)
        except rsm.RSMNotFoundError:
            rsm_request = None
        node = element['node'] if element.hasAttribute('node') else None
        return MAMQueryRequest(form, rsm_request, node)

    def toElement(self):
        """
        Return the DOM representation of this RSM <query/> request.

        @rtype: L{Element<twisted.words.xish.domish.Element>}
        """
        mam_elt = domish.Element((NS_MAM, 'query'))
        if self.node is not None:
            mam_elt['node'] = self.node
        if self.form is not None:
            mam_elt.addChild(self.form.toElement())
        if self.rsm is not None:
            mam_elt.addChild(self.rsm.toElement())

        return mam_elt

    def render(self, parent):
        """Embed the DOM representation of this MAM request in the given element.

        @param parent: parent IQ element.
        @type parent: L{Element<twisted.words.xish.domish.Element>}

        @return: MAM request element.
        @rtype: L{Element<twisted.words.xish.domish.Element>}
        """
        assert parent.name == 'iq'
        mam_elt = self.toElement()
        parent.addChild(mam_elt)
        return mam_elt


class MAMPrefs():
    """
    A Message Archive Management <prefs/> request.

    @param default: A value in ('always', 'never', 'roster').
    @type : C{unicode} or C{None}

    @param always (list): A list of JID instances.
    @type always: C{list}

    @param never (list): A list of JID instances.
    @type never: C{list}
    """

    def __init__(self, default=None, always=None, never=None):
        if default is not None:
            assert default in ('always', 'never', 'roster')
        self.default = default
        if always is not None:
            assert isinstance(always, list)
        else:
            always = []
        self.always = always
        if never is not None:
            assert isinstance(never, list)
        else:
            never = []
        self.never = never

    @classmethod
    def parse(cls, element):
        """Parse the DOM representation of a MAM <prefs/> request.

        @param element: MAM <prefs/> request element.
        @type element: L{Element<twisted.words.xish.domish.Element>}

        @return: MAMPrefs instance.
        @rtype: L{MAMPrefs}
        """
        if element.uri != NS_MAM or element.name != 'prefs':
            raise MAMError('Element provided is not a MAM <prefs/> request')
        default = element['default'] if element.hasAttribute('default') else None
        prefs = {}
        for attr in ('always', 'never'):
            prefs[attr] = []
            try:
                pref = domish.generateElementsNamed(element.elements(), attr).next()
                for jid_s in domish.generateElementsNamed(pref.elements(), 'jid'):
                    prefs[attr].append(jid.JID(jid_s))
            except StopIteration:
                pass
        return MAMPrefs(default, **prefs)

    def toElement(self):
        """
        Return the DOM representation of this RSM <prefs/>request.

        @rtype: L{Element<twisted.words.xish.domish.Element>}
        """
        mam_elt = domish.Element((NS_MAM, 'prefs'))
        if self.default:
            mam_elt['default'] = self.default
        for attr in ('always', 'never'):
            attr_elt = mam_elt.addElement(attr)
            jids = getattr(self, attr)
            for jid_ in jids:
                attr_elt.addElement('jid', content=jid_.full())
        return mam_elt

    def render(self, parent):
        """Embed the DOM representation of this MAM request in the given element.

        @param parent: parent IQ element.
        @type parent: L{Element<twisted.words.xish.domish.Element>}

        @return: MAM request element.
        @rtype: L{Element<twisted.words.xish.domish.Element>}
        """
        assert parent.name == 'iq'
        mam_elt = self.toElement()
        parent.addChild(mam_elt)
        return mam_elt


class MAMClient(XMPPHandler):
    """
    MAM client.

    This handler implements the protocol for sending out MAM requests.
    """

    def queryArchive(self, service=None, form=None, rsm=None, node=None, sender=None):
        """Query a user, MUC or pubsub archive.

        @param service: Entity offering the MAM service (None for user archives).
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @param form: Data Form to filter the request.
        @type form: L{Form<wokkel.data_form.Form>}

        @param rsm: RSM request instance.
        @type rsm: L{RSMRequest<wokkel.rsm.RSMRequest>}

        @param node: Pubsub node to query, or None if inappropriate.
        @type node: C{unicode}

        @param sender: Optional sender address.
        @type sender: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @return: A deferred that fires upon receiving a response.
        @rtype: L{Deferred<twisted.internet.defer.Deferred>}
        """
        iq = IQ(self.xmlstream, 'set')
        MAMQueryRequest(form, rsm, node).render(iq)
        if sender is not None:
            iq['from'] = unicode(sender)
        return iq.send(to=service.full() if service else None)

    def queryFields(self, service=None, sender=None):
        """Ask the server about additional supported fields.

        @param service: Entity offering the MAM service (None for user archives).
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @param sender: Optional sender address.
        @type sender: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @return: A deferred that fires upon receiving a response.
        @rtype: L{Deferred<twisted.internet.defer.Deferred>}
        """
        # http://xmpp.org/extensions/xep-0313.html#query-form
        iq = IQ(self.xmlstream, 'get')
        MAMQueryRequest().render(iq)
        if sender is not None:
            iq['from'] = unicode(sender)
        return iq.send(to=service.full() if service else None)

    def queryPrefs(self, service=None, sender=None):
        """Retrieve the current user preferences.

        @param service: Entity offering the MAM service (None for user archives).
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @param sender: Optional sender address.
        @type sender: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @return: A deferred that fires upon receiving a response.
        @rtype: L{Deferred<twisted.internet.defer.Deferred>}
        """
        # http://xmpp.org/extensions/xep-0313.html#prefs
        iq = IQ(self.xmlstream, 'get')
        MAMPrefs().render(iq)
        if sender is not None:
            iq['from'] = unicode(sender)
        return iq.send(to=service.full() if service else None)

    def setPrefs(self, service=None, default='roster', always=None, never=None, sender=None):
        """Set new user preferences.

        @param service: Entity offering the MAM service (None for user archives).
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @param default: A value in ('always', 'never', 'roster').
        @type : C{unicode}

        @param always (list): A list of JID instances.
        @type always: C{list}

        @param never (list): A list of JID instances.
        @type never: C{list}

        @param sender: Optional sender address.
        @type sender: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @return: A deferred that fires upon receiving a response.
        @rtype: L{Deferred<twisted.internet.defer.Deferred>}
        """
        # http://xmpp.org/extensions/xep-0313.html#prefs
        assert default is not None
        iq = IQ(self.xmlstream, 'set')
        MAMPrefs(default, always, never).render(iq)
        if sender is not None:
            iq['from'] = unicode(sender)
        return iq.send(to=service.full() if service else None)


class IMAMResource(Interface):

    def onArchiveRequest(self, mam, requestor):
        """

        @param mam: The MAM <query/> request.
        @type mam: L{MAMQueryReques<wokkel.mam.MAMQueryRequest>}

        @param requestor: JID of the requestor.
        @type requestor: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @return: The RSM answer.
        @rtype: L{RSMResponse<wokkel.rsm.RSMResponse>}
        """

    def onPrefsGetRequest(self, requestor):
        """

        @param requestor: JID of the requestor.
        @type requestor: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @return: The current settings.
        @rtype: L{wokkel.mam.MAMPrefs}
        """

    def onPrefsSetRequest(self, prefs, requestor):
        """

        @param prefs: The new settings to set.
        @type prefs: L{wokkel.mam.MAMPrefs}

        @param requestor: JID of the requestor.
        @type requestor: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @return: The new current settings.
        @rtype: L{wokkel.mam.MAMPrefs}
        """


class MAMService(XMPPHandler, IQHandlerMixin):
    """
    Protocol implementation for a MAM service.

    This handler waits for XMPP Ping requests and sends a response.
    """

    implements(disco.IDisco)

    iqHandlers = {FIELDS_REQUEST: '_onFieldsRequest',
                  ARCHIVE_REQUEST: '_onArchiveRequest',
                  PREFS_GET_REQUEST: '_onPrefsGetRequest',
                  PREFS_SET_REQUEST: '_onPrefsSetRequest'
                  }

    _legacyFilters = {'start': {'fieldType': 'text-single',
                                'var': 'start',
                                'label': 'Starting time',
                                'desc': 'Starting time a the result period.',
                                },
                      'end': {'fieldType': 'text-single',
                              'var': 'end',
                              'label': 'Ending time',
                              'desc': 'Ending time of the result period.',
                              },
                      'with': {'fieldType': 'jid-single',
                               'var': 'with',
                               'label': 'Entity',
                               'desc': 'Entity against which to match message.',
                               },
                      }

    def __init__(self, resource):
        """
        @param resource: instance implementing IMAMResource
        @type resource: L{object}
        """
        self.resource = resource
        self.extra_filters = {}

    def connectionInitialized(self):
        """
        Called when the XML stream has been initialized.

        This sets up an observer for incoming ping requests.
        """
        self.xmlstream.addObserver(FIELDS_REQUEST, self.handleRequest)
        self.xmlstream.addObserver(ARCHIVE_REQUEST, self.handleRequest)
        self.xmlstream.addObserver(PREFS_GET_REQUEST, self.handleRequest)
        self.xmlstream.addObserver(PREFS_SET_REQUEST, self.handleRequest)

    def addFilter(self, field):
        """
        Add a new filter for querying MAM archive.

        @param field: dictionary specifying the attributes to build a
            wokkel.data_form.Field.
        @type field: C{dict}
        """
        self.extra_filters[field.var] = field

    def _onFieldsRequest(self, iq):
        """
        Called when a fields request has been received.

        This immediately replies with a result response.
        """
        response = toResponse(iq, 'result')
        query = response.addElement((NS_MAM, 'query'))
        query.addChild(buildForm('form', extra=self.extra_filters).toElement())
        self.xmlstream.send(response)
        iq.handled = True

    def _onArchiveRequest(self, iq):
        """
        Called when a message archive request has been received.

        This immediately replies with a result response, followed by the
        list of archived message and the finally the <fin/> message.
        """
        response = toResponse(iq, 'result')
        self.xmlstream.send(response)

        mam_ = MAMQueryRequest.parse(iq.query)
        requestor = jid.JID(iq['from'])

        # remove unsupported filters
        unsupported_fields = []
        if mam_.form:
            for key, field in mam_.form.fields.iteritems():
                if key not in self._legacyFilters and key not in self.extra_filters:
                    log.msg('Ignored unsupported MAM filter: %s' % field)
                    unsupported_fields.append(key)
        for key in unsupported_fields:
            del mam_.form.fields[key]

        def forward_message(id_, elt, date):
            msg = domish.Element((None, 'message'))
            msg['to'] = iq['from']
            result = msg.addElement('result', NS_MAM)
            if iq.hasAttribute('queryid'):
                result['queryid'] = iq.query['queryid']
            result['id'] = id_
            forward = result.addElement('forwarded', NS_FORWARD)
            forward.addChild(delay.Delay(date).toElement())
            forward.addChild(elt)
            self.xmlstream.send(msg)

        def cb(result):
            msg_data, rsm_elt = result
            for data in msg_data:
                forward_message(*data)
            msg = domish.Element((None, 'message'))
            msg['to'] = iq['from']
            fin = msg.addElement('fin', NS_MAM)
            if iq.hasAttribute('queryid'):
                fin['queryid'] = iq.query['queryid']
            if rsm_elt is not None:
                fin.addChild(rsm_elt)
            self.xmlstream.send(msg)

        self.resource.onArchiveRequest(mam_, requestor).addCallback(cb)
        iq.handled = True

    def _onPrefsGetRequest(self, iq):
        """
        Called when a prefs get request has been received.

        This immediately replies with a result response.
        """
        response = toResponse(iq, 'result')

        requestor = jid.JID(iq['from'])

        def cb(prefs):
            response.addChild(prefs.toElement())
            self.xmlstream.send(response)

        self.resource.onPrefsGetRequest(requestor).addCallback(cb)
        iq.handled = True

    def _onPrefsSetRequest(self, iq):
        """
        Called when a prefs get request has been received.

        This immediately replies with a result response.
        """
        response = toResponse(iq, 'result')

        prefs = MAMPrefs.parse(iq.prefs)
        requestor = jid.JID(iq['from'])

        def cb(prefs):
            response.addChild(prefs.toElement())
            self.xmlstream.send(response)

        self.resource.onPrefsSetRequest(prefs, requestor).addCallback(cb)
        iq.handled = True

    def getDiscoInfo(self, requestor, target, nodeIdentifier=''):
        if nodeIdentifier:
            return []
        return [disco.DiscoFeature(NS_MAM)]

    def getDiscoItems(self, requestor, target, nodeIdentifier=''):
        return []


def datetime2utc(datetime):
    """Convert a datetime to a XEP-0082 compliant UTC datetime.

    @param datetime: Offset-aware timestamp to convert.
    @type datetime: L{datetime<datetime.datetime>}

    @return: The datetime converted to UTC.
    @rtype: C{unicode}
    """
    stampFormat = '%Y-%m-%dT%H:%M:%SZ'
    return datetime.astimezone(tzutc()).strftime(stampFormat)


def buildForm(formType='submit', start=None, end=None, with_jid=None, extra=None):
    """Prepare a Data Form for MAM.

    @param formType: The type of the Data Form ('submit' or 'form').
    @type formType: C{unicode}

    @param start: Offset-aware timestamp to filter out older messages.
    @type start: L{datetime<datetime.datetime>}

    @param end: Offset-aware timestamp to filter out later messages.
    @type end: L{datetime<datetime.datetime>}

    @param with_jid: JID against which to match messages.
    @type with_jid: L{JID<twisted.words.protocols.jabber.jid.JID>}

    @param extra: list of extra fields that are not defined by the
        specification. Each element of the list must be a dictionary
        specifying the attributes to build a wokkel.data_form.Field.
    @type: C{list}

    @return: XEP-0004 Data Form object.
    @rtype: L{Form<wokkel.data_form.Form>}
    """
    form = data_form.Form(formType, formNamespace=NS_MAM)
    filters = []

    if formType == 'form':
        filters.extend(MAMService._legacyFilters.values())
    elif formType == 'submit':
        if start:
            filters.append({'var': 'start', 'value': datetime2utc(start)})
        if end:
            filters.append({'var': 'end', 'value': datetime2utc(end)})
        if with_jid:
            # must specify the field type to overwrite default value in Field.__init__
            filters.append({'fieldType': 'jid-single', 'var': 'with', 'value': with_jid.full()})

    if extra is not None:
        filters.extend(extra)

    for field in filters:
        form.addField(data_form.Field(**field))

    return form