#!/usr/bin/python
# -*- coding: utf-8 -*-

# SAT plugin for Publish-Subscribe (xep-0060)
# Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014 Jérôme Poisson (goffi@goffi.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 _
from sat.core.constants import Const as C
from sat.core.log import getLogger
log = getLogger(__name__)
from sat.memory.memory import Sessions

from wokkel.compat import IQ
from wokkel import disco, pubsub
from wokkel.pubsub import PubSubRequest, NS_PUBSUB
from zope.interface import implements
from twisted.internet import defer


PLUGIN_INFO = {
    "name": "Publish-Subscribe",
    "import_name": "XEP-0060",
    "type": "XEP",
    "protocols": ["XEP-0060"],
    "dependencies": [],
    "recommendations": ["XEP-0059"],
    "main": "XEP_0060",
    "handler": "yes",
    "description": _("""Implementation of PubSub Protocol""")
}


class XEP_0060(object):
    OPT_ACCESS_MODEL = 'pubsub#access_model'
    OPT_PERSIST_ITEMS = 'pubsub#persist_items'
    OPT_MAX_ITEMS = 'pubsub#max_items'
    OPT_DELIVER_PAYLOADS = 'pubsub#deliver_payloads'
    OPT_SEND_ITEM_SUBSCRIBE = 'pubsub#send_item_subscribe'
    OPT_NODE_TYPE = 'pubsub#node_type'
    OPT_SUBSCRIPTION_TYPE = 'pubsub#subscription_type'
    OPT_SUBSCRIPTION_DEPTH = 'pubsub#subscription_depth'
    OPT_ROSTER_GROUPS_ALLOWED = 'pubsub#roster_groups_allowed'
    OPT_PUBLISH_MODEL = 'pubsub#publish_model'

    def __init__(self, host):
        log.info(_("PubSub plugin initialization"))
        self.host = host
        self.managedNodes = []
        self.clients = {}
        self.node_cache = Sessions(timeout=60, resettable_timeout=False)

    def getHandler(self, profile):
        self.clients[profile] = SatPubSubClient(self.host, self)
        return self.clients[profile]

    def addManagedNode(self, node_name, callback):
        """Add a handler for a namespace
        @param namespace: NS of the handler (will appear in disco info)
        @param callback: method to call when the handler is found
        @param profile: profile which manage this handler"""
        self.managedNodes.append((node_name, callback))

    def __getClientNProfile(self, profile_key, action='do pusbsub'):
        """Return a tuple of (client, profile)
        raise error when the profile doesn't exists
        @param profile_key: as usual :)
        @param action: text of action to show in case of error"""
        profile = self.host.memory.getProfileName(profile_key)
        if not profile:
            err_mess = _('Trying to %(action)s with an unknown profile key [%(profile_key)s]') % {
                'action': action,
                'profile_key': profile_key}
            log.error(err_mess)
            raise Exception(err_mess)
        try:
            client = self.clients[profile]
        except KeyError:
            err_mess = _('INTERNAL ERROR: no handler for required profile')
            log.error(err_mess)
            raise Exception(err_mess)
        return profile, client

    def _getDeferredNodeCache(self, session_id, init, profile):
        """Manage a node cache with deferred initialisation and concurrent access.

        @param session_id (string): node cache session ID
        @param init (Deferred): deferred list of strings to initialise the cache.
        @param profile (str): %(doc_profile)s
        @return: Deferred list[str]
        """
        if session_id in self.node_cache:
            cache = self.node_cache.profileGet(session_id, profile)
            if cache['nodes'] is None:
                # init is still running
                d = defer.Deferred()
                cache['waiting'].append(d)
                return d
            return defer.succeed(cache['nodes'])

        cache = {'init': init, 'waiting': [], 'nodes': None}
        self.node_cache.newSession(cache, session_id=session_id, profile=profile)

        def cb(nodes):
            cache['nodes'] = nodes
            for d in cache['waiting']:
                d.callback(nodes)
            return nodes

        return init.addCallback(cb)

    def listNodes(self, service, nodeIdentifier='', profile=C.PROF_KEY_NONE):
        """Retrieve the name of the nodes that are accessible on the target service.

        @param service (JID): target service
        @param nodeIdentifier (str): the parent node name (leave empty to retrieve first-level nodes)
        @param profile (str): %(doc_profile)s
        @return: Deferred list[str]
        """
        session_id = profile + '@found@' + service.userhost()
        d = self.getDiscoItems(service, nodeIdentifier, profile_key=profile)
        d.addCallback(lambda result: [item.getAttribute('node') for item in result.toElement().children if item.hasAttribute('node')])
        return self._getDeferredNodeCache(session_id, d, profile)

    def listSubscribedNodes(self, service, nodeIdentifier='', filter_='subscribed', profile=C.PROF_KEY_NONE):
        """Retrieve the name of the nodes to which the profile is subscribed on the target service.

        @param service (JID): target service
        @param nodeIdentifier (str): the parent node name (leave empty to retrieve all subscriptions)
        @param filter_ (str): filter the result according to the given subscription type:
            - None: do not filter
            - 'pending': subscription has been approved yet by the node owner
            - 'unconfigured': subscription options have not been configured yet
            - 'subscribed': subscription is complete
        @param profile (str): %(doc_profile)s
        @return: Deferred list[str]
        """
        session_id = profile + '@subscriptions@' + service.userhost()
        d = self.subscriptions(service, nodeIdentifier, profile_key=profile)
        d.addCallback(lambda subs: [sub.getAttribute('node') for sub in subs if sub.getAttribute('subscription') == filter_])
        return self._getDeferredNodeCache(session_id, d, profile)

    def publish(self, service, nodeIdentifier, items=None, profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'publish item')
        return client.publish(service, nodeIdentifier, items, client.parent.jid)

    def getItems(self, service, node, max_items=None, item_ids=None, sub_id=None, profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'get items')
        return client.items(service, node, max_items, item_ids, sub_id, client.parent.jid)

    @defer.inlineCallbacks
    def getItemsFromMany(self, service, data, max_items=None, item_ids=None, sub_id=None, profile_key=C.PROF_KEY_NONE):
        """Massively retrieve pubsub items from many nodes.

        @param service (JID): target service.
        @param data (dict): dictionnary binding some arbitrary keys to the node identifiers.
        @param max_items (int): optional limit on the number of retrieved items *per node*.
        @param item_ids (list[str]): identifiers of the items to be retrieved (should not be used).
        @param sub_id (str): optional subscription identifier.
        @param profile_key (str): %(doc_profile_key)s
        @return: dict binding a subset of the keys of data to Deferred instances.
        """
        profile, client = self.__getClientNProfile(profile_key, 'get items')
        found_nodes = yield self.listNodes(service, profile=profile)
        d_dict = {}
        for publisher, node in data.items():
            if node not in found_nodes:
                log.debug("Skip the items retrieval for [{node}]: node doesn't exist".format(node=node))
                continue  # avoid pubsub "item-not-found" error
            d_dict[publisher] = client.items(service, node, max_items, item_ids, sub_id, client.parent.jid)
        defer.returnValue(d_dict)

    def getOptions(self, service, nodeIdentifier, subscriber, subscriptionIdentifier=None, profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'get options')
        return client.getOptions(service, nodeIdentifier, subscriber, subscriptionIdentifier)

    def setOptions(self, service, nodeIdentifier, subscriber, options, subscriptionIdentifier=None, profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'set options')
        return client.setOptions(service, nodeIdentifier, subscriber, options, subscriptionIdentifier)

    def createNode(self, service, nodeIdentifier, options, profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'create node')
        return client.createNode(service, nodeIdentifier, options)

    def deleteNode(self, service, nodeIdentifier, profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'delete node')
        return client.deleteNode(service, nodeIdentifier)

    def retractItems(self, service, nodeIdentifier, itemIdentifiers, profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'retract items')
        return client.retractItems(service, nodeIdentifier, itemIdentifiers)

    def subscribe(self, service, nodeIdentifier, sub_jid=None, options=None, profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'subscribe node')
        return client.subscribe(service, nodeIdentifier, sub_jid or client.parent.jid.userhostJID(), options=options)

    @defer.inlineCallbacks
    def subscribeToMany(self, service, nodeIdentifiers, sub_jid=None, options=None, profile_key=C.PROF_KEY_NONE):
        """Massively subscribe to many nodes.

        @param service (JID): target service.
        @param nodeIdentifiers (list): the list of node identifiers to subscribe to.
        @param sub_id (str): optional subscription identifier.
        @param options (list): optional list of subscription options
        @param profile_key (str): %(doc_profile_key)s
        @return: list of Deferred instances.
        """
        profile, client = self.__getClientNProfile(profile_key, 'subscribe nodes')
        found_nodes = yield self.listNodes(service, profile=profile)
        subscribed_nodes = yield self.listSubscribedNodes(service, profile=profile)
        d_list = []
        for nodeIdentifier in (set(nodeIdentifiers) - set(subscribed_nodes)):
            if nodeIdentifier not in found_nodes:
                log.debug("Skip the subscription to [{node}]: node doesn't exist".format(node=nodeIdentifier))
                continue  # avoid sat-pubsub "SubscriptionExists" error
            d_list.append(client.subscribe(service, nodeIdentifier, sub_jid or client.parent.jid.userhostJID(), options=options))
        defer.returnValue(d_list)

    def subscriptions(self, service, nodeIdentifier='', profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'retrieve subscriptions')
        return client.subscriptions(service, nodeIdentifier)

    def getDiscoItems(self, service, nodeIdentifier='', profile_key=C.PROF_KEY_NONE):
        profile, client = self.__getClientNProfile(profile_key, 'disco items')
        return client.getDiscoItems(None, service, nodeIdentifier)


class SatPubSubClient(pubsub.PubSubClient):
    implements(disco.IDisco)

    def __init__(self, host, parent_plugin):
        self.host = host
        self.parent_plugin = parent_plugin
        pubsub.PubSubClient.__init__(self)

    def connectionInitialized(self):
        pubsub.PubSubClient.connectionInitialized(self)

    # FIXME: we have to temporary override this method here just
    # to set the attributes itemIdentifiers which is not used
    # in pubsub.PubSubClient.items + use the XEP-0059
    def items(self, service, nodeIdentifier, maxItems=None, itemIdentifiers=None,
              subscriptionIdentifier=None, sender=None):
        """
        Retrieve previously published items from a publish subscribe node.

        @param service: The publish subscribe service that keeps the node.
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}

        @param nodeIdentifier: The identifier of the node.
        @type nodeIdentifier: C{unicode}

        @param maxItems: Optional limit on the number of retrieved items.
        @type maxItems: C{int}

        @param itemIdentifiers: Identifiers of the items to be retrieved.
        @type itemIdentifiers: C{set}

        @param subscriptionIdentifier: Optional subscription identifier. In
            case the node has been subscribed to multiple times, this narrows
            the results to the specific subscription.
        @type subscriptionIdentifier: C{unicode}
        """
        # TODO: add method attributes for RSM: before, after, index
        request = PubSubRequest('items', self.host, {'limit': maxItems} if maxItems else {})
        request.recipient = service
        request.nodeIdentifier = nodeIdentifier
        if maxItems:
            request.maxItems = str(int(maxItems))
        request.subscriptionIdentifier = subscriptionIdentifier
        request.sender = sender
        request.itemIdentifiers = itemIdentifiers  # XXX: this line has been added

        def cb(iq):
            items = []
            for element in iq.pubsub.items.elements():
                if element.uri == NS_PUBSUB and element.name == 'item':
                    items.append(element)
            # TODO: return (items, self.host.plugins['XEP-0059'].extractMetadata(iq)) ??
            return items

        d = request.send(self.xmlstream)
        d.addCallback(cb)
        return d

    # FIXME: this should be done in wokkel
    def retractItems(self, service, nodeIdentifier, itemIdentifiers, sender=None):
        """
        Retract items from a publish subscribe node.

        @param service: The publish subscribe service to delete the node from.
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}
        @param nodeIdentifier: The identifier of the node.
        @type nodeIdentifier: C{unicode}
        @param itemIdentifiers: Identifiers of the items to be retracted.
        @type itemIdentifiers: C{set}
        """
        request = PubSubRequest('retract')
        request.recipient = service
        request.nodeIdentifier = nodeIdentifier
        request.itemIdentifiers = itemIdentifiers
        request.sender = sender
        return request.send(self.xmlstream)

    def itemsReceived(self, event):
        if not self.host.trigger.point("PubSubItemsReceived", event, self.parent.profile):
            return
        for node in self.parent_plugin.managedNodes:
            if event.nodeIdentifier == node[0]:
                node[1](event, self.parent.profile)

    def deleteReceived(self, event):
        #TODO: manage delete event
        log.debug(_("Publish node deleted"))

    # def purgeReceived(self, event):

    @defer.inlineCallbacks
    def subscriptions(self, service, nodeIdentifier, sender=None):
        """Return the list of subscriptions to the given service and node.

        @param service: The publish subscribe service to retrieve the subscriptions from.
        @type service: L{JID<twisted.words.protocols.jabber.jid.JID>}
        @param nodeIdentifier: The identifier of the node (leave empty to retrieve all subscriptions).
        @type nodeIdentifier: C{unicode}
        """
        request = PubSubRequest('subscriptions')
        request.recipient = service
        request.nodeIdentifier = nodeIdentifier
        request.sender = sender
        iq = yield request.send(self.xmlstream)
        defer.returnValue([sub for sub in iq.pubsub.subscriptions.elements() if
                           (sub.uri == NS_PUBSUB and sub.name == 'subscription')])

    def getDiscoInfo(self, requestor, service, nodeIdentifier=''):
        disco_info = []
        self.host.trigger.point("PubSub Disco Info", disco_info, self.parent.profile)
        return disco_info

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


class PubSubRequest(pubsub.PubSubRequest):

    def __init__(self, verb=None, host=None, page_attrs=None):
        """
        @param verb (str): the type of pubsub request
        @param host (SAT): the SAT instance
        @param page_attrs (dict): options for RSM paging:
            - limit (int): the maximum number of items in the page
            - index (int): the starting index of the requested page
            - after (str, int): the element immediately preceding the page
            - before (str, int): the element immediately following the page
        """
        self.verb = verb
        self.host = host
        self.page_attrs = page_attrs

    # FIXME: the redefinition of this wokkel method is the easiest way I found
    # to handle RSM. We should find a proper solution, maybe just add in wokkel an
    # empty method postProcessMessage, call it before sending and overwrite it here
    # instead of overwriting the whole send method.
    def send(self, xs):
        """
        Send this request to its recipient.

        This renders all of the relevant parameters for this specific
        requests into an L{IQ}, and invoke its C{send} method.
        This returns a deferred that fires upon reception of a response. See
        L{IQ} for details.

        @param xs: The XML stream to send the request on.
        @type xs: L{twisted.words.protocols.jabber.xmlstream.XmlStream}
        @rtype: L{defer.Deferred}.
        """

        try:
            (self.stanzaType,
             childURI,
             childName) = self._verbRequestMap[self.verb]
        except KeyError:
            raise NotImplementedError()

        iq = IQ(xs, self.stanzaType)
        iq.addElement((childURI, 'pubsub'))
        verbElement = iq.pubsub.addElement(childName)

        if self.sender:
            iq['from'] = self.sender.full()
        if self.recipient:
            iq['to'] = self.recipient.full()

        for parameter in self._parameters[self.verb]:
            getattr(self, '_render_%s' % parameter)(verbElement)

        # This lines have been added for RSM
        if self.host and 'XEP-0059' in self.host.plugins and self.page_attrs:
            self.page_attrs['stanza'] = iq
            self.host.plugins['XEP-0059'].requestPage(**self.page_attrs)

        return iq.send()