#!/usr/bin/env python2
# -*- coding: utf-8 -*-

# SAT plugin for Delayed Delivery (XEP-0334)
# Copyright (C) 2009-2016 Jérôme Poisson (goffi@goffi.org)
# Copyright (C) 2013-2016 Adrien 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/>.

from sat.core.i18n import _, D_
from sat.core.log import getLogger
log = getLogger(__name__)

from sat.core import exceptions
from sat.tools.common import data_format

from wokkel import disco, iwokkel
try:
    from twisted.words.protocols.xmlstream import XMPPHandler
except ImportError:
    from wokkel.subprotocols import XMPPHandler
from twisted.python import failure
from zope.interface import implements
from textwrap import dedent


PLUGIN_INFO = {
    "name": u"Message Processing Hints",
    "import_name": u"XEP-0334",
    "type": u"XEP",
    "protocols": [u"XEP-0334"],
    "main": "XEP_0334",
    "handler": u"yes",
    "description": D_(u"""Implementation of Message Processing Hints"""),
    "usage": dedent(D_(u"""\
             Frontends can use HINT_* constants in mess_data['extra'] in a serialized 'hints' dict.
             Internal plugins can use directly addHint([HINT_* constant]).
             Will set mess_data['extra']['history'] to 'skipped' when no store is requested and message is not saved in history."""))

}

NS_HINTS = u'urn:xmpp:hints'


class XEP_0334(object):
    HINT_NO_PERMANENT_STORE = u'no-permanent-store'
    HINT_NO_STORE = u'no-store'
    HINT_NO_COPY = u'no-copy'
    HINT_STORE = u'store'
    HINTS = (HINT_NO_PERMANENT_STORE, HINT_NO_STORE, HINT_NO_COPY, HINT_STORE)

    def __init__(self, host):
        log.info(_("Message Processing Hints plugin initialization"))
        self.host = host
        host.trigger.add("messageSend", self.messageSendTrigger)
        host.trigger.add("MessageReceived", self.messageReceivedTrigger, priority=-1000)

    def getHandler(self, profile):
        return XEP_0334_handler()

    def addHint(self, mess_data, hint):
        if hint == self.HINT_NO_COPY and not mess_data['to'].resource:
            log.error(u"{hint} can only be used with full jids! Ignoring it.".format(hint=hint))
            return
        hints = mess_data.setdefault('hints', set())
        if hint in self.HINTS:
            hints.add(hint)
        else:
            log.error(u"Unknown hint: {}".format(hint))

    def _sendPostXmlTreatment(self, mess_data):
        if 'hints' in mess_data:
            for hint in mess_data['hints']:
                mess_data[u'xml'].addElement((NS_HINTS, hint))
        return mess_data

    def messageSendTrigger(self, client, mess_data, pre_xml_treatments, post_xml_treatments):
        """Add the hints element to the message to be sent"""
        if u'hints' in mess_data[u'extra']:
            for hint in data_format.dict2iter(u'hints', mess_data[u'extra'], pop=True):
                self.addHint(hint)

        post_xml_treatments.addCallback(self._sendPostXmlTreatment)
        return True

    def _receivedSkipHistory(self, mess_data):
        mess_data[u'extra'][u'history'] == u'skipped'
        raise failure.Failure(exceptions.SkipHistory())


    def messageReceivedTrigger(self, client, message_elt, post_treat):
        """Check for hints in the received message"""
        for elt in message_elt.elements():
            if elt.uri == NS_HINTS and elt.name in (self.HINT_NO_PERMANENT_STORE, self.HINT_NO_STORE):
                log.debug(u"history will be skipped for this message, as requested")
                post_treat.addCallback(self._receivedSkipHistory)
                break
        return True


class XEP_0334_handler(XMPPHandler):
    implements(iwokkel.IDisco)

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

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