from twisted.protocols.jabber import jid
from twisted.python import components
from twisted.application import service
from twisted.xish import utility
from twisted.internet import defer
import sha
import time

class Error(Exception):
    msg = ''

    def __str__(self):
        return self.msg
    
class NodeNotFound(Error):
    msg = 'Node not found'

class NotAuthorized(Error):
    pass

class PayloadExpected(Error):
    msg = 'Payload expected'

class NoPayloadAllowed(Error):
    msg = 'No payload allowed'

class NoInstantNodes(Error):
    pass

class NodeExists(Error):
    pass

class NotImplemented(Error):
    pass

class NotSubscribed(Error):
    pass

class IBackendService(components.Interface):
    """ Interface to a backend service of a pubsub service. """

    def get_supported_affiliations(self):
        """ Reports the list of supported affiliation types.
    
        @return: a list of supported affiliation types.
        """

class INodeCreationService(components.Interface):
    """ A service for creating nodes """

    def create_node(self, node_id, requestor):
        """ Create a node.
        
        @return: a deferred that fires when the node has been created.
        """

class INodeDeletionService(components.Interface):
    """ A service for deleting nodes. """

    def register_pre_delete(self, pre_delete_fn):
        """ Register a callback that is called just before a node deletion.
        
        The function C{pre_deleted_fn} is added to a list of functions
        to be called just before deletion of a node. The callback
        C{pre_delete_fn} is called with the C{node_id} that is about to be
        deleted and should return a deferred that returns a list of deferreds
        that are to be fired after deletion. The backend collects the lists
        from all these callbacks before actually deleting the node in question.
        After deletion all collected deferreds are fired to do post-processing.

        The idea is that you want to be able to collect data from the
        node before deleting it, for example to get a list of subscribers
        that have to be notified after the node has been deleted. To do this,
        C{pre_delete_fn} fetches the subscriber list and passes this
        list to a callback attached to a deferred that it sets up. This
        deferred is returned in the list of deferreds.
        """

    def get_subscribers(self, node_id):
        """ Get node subscriber list.
        
        @return: a deferred that fires with the list of subscribers.
        """

    def delete_node(self, node_id, requestor):
        """ Delete a node.
        
        @return: a deferred that fires when the node has been deleted.
        """

class IPublishService(components.Interface):
    """ A service for publishing items to a node. """

    def publish(self, node_id, items, requestor):
        """ Publish items to a pubsub node.
        
        @return: a deferred that fires when the items have been published.
        """
class INotificationService(components.Interface):
    """ A service for notification of published items. """

    def register_notifier(self, observerfn, *args, **kwargs):
        """ Register callback which is called for notification. """

    def get_notification_list(self, node_id, items):
        pass

class ISubscriptionService(components.Interface):
    """ A service for managing subscriptions. """

    def subscribe(self, node_id, subscriber, requestor):
        """ Request the subscription of an entity to a pubsub node.

        Depending on the node's configuration and possible business rules, the
        C{subscriber} is added to the list of subscriptions of the node with id
        C{node_id}. The C{subscriber} might be different from the C{requestor},
        and if the C{requestor} is not allowed to subscribe this entity an
        exception should be raised.

        @return: a deferred that returns the subscription state
        """

    def unsubscribe(self, node_id, subscriber, requestor):
        """ Cancel the subscription of an entity to a pubsub node.

        The subscription of C{subscriber} is removed from the list of
        subscriptions of the node with id C{node_id}. If the C{requestor}
        is not allowed to unsubscribe C{subscriber}, an an exception should
        be raised.

        @return: a deferred that fires when unsubscription is complete.
        """

class IAffiliationsService(components.Interface):
    """ A service for retrieving the affiliations with this pubsub service. """

    def get_affiliations(self, entity):
        """ Report the list of current affiliations with this pubsub service.

        Report the list of the current affiliations with all nodes within this
        pubsub service, along with subscriptions to such nodes, for the
        C{entity}.

        @return: a deferred that returns the list of all current affiliations
        and subscriptions.
        """

class IRetractionService(components.Interface):
    """ A service for retracting published items """

    def retract_item(self, node_id, item_id, requestor):
        """ Removes item in node from persistent storage """

    def purge_node(self, node_id, requestor):
        """ Removes all items in node from persistent storage """

class IItemRetrievalService(components.Interface):
    """ A service for retrieving previously published items. """

    def get_items(self, node_id, requestor, max_items=None, item_ids=[]):
        """ Retrieve items from persistent storage

        If C{max_items} is given, return the C{max_items} last published
        items, else if C{item_ids} is not empty, return the items requested.
        If neither is given, return all items.

        @return: a deferred that returns the requested items
        """

class BackendService(service.MultiService, utility.EventDispatcher):

    __implements__ = IBackendService,

    options = {"pubsub#persist_items":
                  {"type": "boolean",
                   "label": "Persist items to storage"},
               "pubsub#deliver_payloads":
                  {"type": "boolean",
                   "label": "Deliver payloads with event notifications"},
              }

    default_config = {"pubsub#persist_items": True,
                      "pubsub#deliver_payloads": True,
                     }

    def __init__(self, storage):
        service.MultiService.__init__(self)
        utility.EventDispatcher.__init__(self)
        self.storage = storage

    def supports_publisher_affiliation(self):
        return True

    def supports_outcast_affiliation(self):
        return True

    def supports_persistent_items(self):
        return True

    def get_node_type(self, node_id):
        return self.storage.get_node_type(node_id)

    def get_nodes(self):
        return self.storage.get_nodes()

    def get_node_meta_data(self, node_id):
        d = self.storage.get_node_configuration(node_id)

        d.addCallback(self._make_meta_data)
        return d

    def _make_meta_data(self, meta_data):
        options = []
        for key, value in meta_data.iteritems():
            if self.options.has_key(key):
                option = {"var": key}
                option.update(self.options[key])
                option["value"] = value
                options.append(option)

        return options

class PublishService(service.Service):
    
    __implements__ = IPublishService,

    def publish(self, node_id, items, requestor):
        d1 = self.parent.storage.get_node_configuration(node_id)
        d2 = self.parent.storage.get_affiliation(node_id, requestor)
        d = defer.DeferredList([d1, d2], fireOnOneErrback=1, consumeErrors=1)
        d.addErrback(lambda x: x.value[0])
        d.addCallback(self._do_publish, node_id, items, requestor)
        return d

    def _do_publish(self, result, node_id, items, requestor):
        configuration = result[0][1]
        persist_items = configuration["pubsub#persist_items"]
        deliver_payloads = configuration["pubsub#deliver_payloads"]
        affiliation = result[1][1]

        if affiliation not in ['owner', 'publisher']:
            raise NotAuthorized

        if items and not persist_items and not deliver_payloads:
            raise NoPayloadAllowed
        elif not items and (persist_items or deliver_payloads):
            raise PayloadExpected

        if persist_items or deliver_payloads:
            for item in items:
                if not item.getAttribute("id"):
                    item["id"] = sha.new(str(time.time()) +
                                         requestor.full()).hexdigest()

        if persist_items:
            d = self.parent.storage.store_items(node_id, items,
                                                requestor)
        else:
            d = defer.succeed(None)

        d.addCallback(self._do_notify, node_id, items, deliver_payloads)

    def _do_notify(self, result, node_id, items, deliver_payloads):
        if items and not deliver_payloads:
            for item in items:
                item.children = []

        self.parent.dispatch({ 'items': items, 'node_id': node_id },
                             '//event/pubsub/notify')

class NotificationService(service.Service):

    __implements__ = INotificationService,

    def get_notification_list(self, node_id, items):
        d = self.parent.storage.get_subscribers(node_id)
        d.addCallback(self._magic_filter, node_id, items)
        return d

    def _magic_filter(self, subscribers, node_id, items):
        list = {}
        for subscriber in subscribers:
            list[subscriber] = items
        return list

    def register_notifier(self, observerfn, *args, **kwargs):
        self.parent.addObserver('//event/pubsub/notify', observerfn,
                                *args, **kwargs)

class SubscriptionService(service.Service):

    __implements__ = ISubscriptionService,

    def subscribe(self, node_id, subscriber, requestor):
        if subscriber.userhostJID() != requestor:
            raise NotAuthorized

        d1 = self.parent.storage.get_node_configuration(node_id)
        d2 = self.parent.storage.get_affiliation(node_id, subscriber)
        d = defer.DeferredList([d1, d2], fireOnOneErrback=1, consumeErrors=1)
        d.addErrback(lambda x: x.value[0])
        d.addCallback(self._do_subscribe, node_id, subscriber)
        return d

    def _do_subscribe(self, result, node_id, subscriber):
        configuration = result[0][1]
        affiliation = result[1][1]

        if affiliation == 'outcast':
            raise NotAuthorized

        d = self.parent.storage.add_subscription(node_id, subscriber,
                                                 'subscribed')
        d.addCallback(self._return_subscription, affiliation)
        return d

    def _return_subscription(self, result, affiliation):
        result['affiliation'] = affiliation
        return result

    def unsubscribe(self, node_id, subscriber, requestor):
        if subscriber.userhostJID() != requestor:
            raise NotAuthorized

        d = self.parent.storage.get_node_configuration(node_id)
        d.addCallback(self._do_unsubscribe, node_id, subscriber)
        return d

    def _do_unsubscribe(self, result, node_id, subscriber):
        return self.parent.storage.remove_subscription(node_id,
                                                       subscriber)

class NodeCreationService(service.Service):

    __implements__ = INodeCreationService,

    def supports_instant_nodes(self):
        return True

    def create_node(self, node_id, requestor):
        if not node_id:
            node_id = 'generic/%s' % sha.new(str(time.time()) +
                                             requestor.full()).hexdigest()

        d = self.parent.storage.create_node(node_id, requestor)
        d.addCallback(lambda _: node_id)
        return d

    def get_node_configuration(self, node_id):
        if node_id:
            d = self.parent.storage.get_node_configuration(node_id)
        else:
            # XXX: this is disabled in pubsub.py
            d = defer.succeed(self.parent.default_config)

        d.addCallback(self._make_config)
        return d

    def _make_config(self, config):
        options = []
        for key, value in self.parent.options.iteritems():
            option = {"var": key}
            option.update(value)
            if config.has_key(key):
                option["value"] = config[key]
            options.append(option)

        return options

    def set_node_configuration(self, node_id, options, requestor):
        for key in options.iterkeys():
            if not self.parent.options.has_key(key):
                raise InvalidConfigurationOption

        d = self.parent.storage.get_affiliation(node_id, requestor)
        d.addCallback(self._do_set_node_configuration, node_id, options)
        return d

    def _do_set_node_configuration(self, affiliation, node_id, options):
        if affiliation != 'owner':
            raise NotAuthorized

        return self.parent.storage.set_node_configuration(node_id, options)

class AffiliationsService(service.Service):

    __implements__ = IAffiliationsService,

    def get_affiliations(self, entity):
        d1 = self.parent.storage.get_affiliations(entity)
        d2 = self.parent.storage.get_subscriptions(entity)
        d = defer.DeferredList([d1, d2], fireOnOneErrback=1, consumeErrors=1)
        d.addErrback(lambda x: x.value[0])
        d.addCallback(self._affiliations_result, entity)
        return d

    def _affiliations_result(self, result, entity):
        affiliations = result[0][1]
        subscriptions = result[1][1]

        new_affiliations = {}

        for node, affiliation in affiliations:
            new_affiliations[(node, entity.full())] = {'node': node,
                                                'jid': entity,
                                                'affiliation': affiliation,
                                                'subscription': None
                                               }

        for node, subscriber, subscription in subscriptions:
            key = node, subscriber.full()
            if new_affiliations.has_key(key):
                new_affiliations[key]['subscription'] = subscription
            else:
                new_affiliations[key] = {'node': node,
                                         'jid': subscriber,
                                         'affiliation': None,
                                         'subscription': subscription}

        return new_affiliations.values()

class ItemRetrievalService(service.Service):

    __implements__ = IItemRetrievalService

    def get_items(self, node_id, requestor, max_items=None, item_ids=[]):
        d = self.parent.storage.is_subscribed(node_id, requestor)
        d.addCallback(self._do_get_items, node_id, max_items, item_ids)
        return d

    def _do_get_items(self, result, node_id, max_items, item_ids):
        if not result:
            raise NotAuthorized

        if item_ids:
            return self.parent.storage.get_items_by_ids(node_id, item_ids)
        else:
            return self.parent.storage.get_items(node_id, max_items)

class RetractionService(service.Service):

    __implements__ = IRetractionService,
                                                                                
    def retract_item(self, node_id, item_ids, requestor):
        d1 = self.parent.storage.get_node_configuration(node_id)
        d2 = self.parent.storage.get_affiliation(node_id, requestor)
        d = defer.DeferredList([d1, d2], fireOnOneErrback=1)
        d.addErrback(lambda x: x.value[0])
        d.addCallback(self._do_retract, node_id, item_ids)
        return d
                                                                                
    def _do_retract(self, result, node_id, item_ids):
        configuration = result[0][1]
        persist_items = configuration["persist_items"]
        affiliation = result[1][1]
                                                                                
        if affiliation not in ['owner', 'publisher']:
            raise NotAuthorized
                                                                                
        if not persist_items:
            raise NodeNotPersistent
                                                                                
        d = self.parent.storage.remove_items(node_id, item_ids)
        d.addCallback(self._do_notify_retraction, node_id)
        return d
                                                                                
    def _do_notify_retraction(self, result, node_id):
        self.parent.dispatch({ 'item_ids': result, 'node_id': node_id },
                             '//event/pubsub/retract')
                                                                                
    def purge_node(self, node_id, requestor):
        d1 = self.parent.storage.get_node_configuration(node_id)
        d2 = self.parent.storage.get_affiliation(node_id, requestor)
        d = defer.DeferredList([d1, d2], fireOnOneErrback=1)
        d.addErrback(lambda x: x.value[0])
        d.addCallback(self._do_purge, node_id)
        return d
    
    def _do_purge(self, result, node_id):
        configuration = result[0][1]
        persist_items = configuration["persist_items"]
        affiliation = result[1][1]
                                                                                
        if affiliation != 'owner':
            raise NotAuthorized
                                                                                
        if not persist_items:
            raise NodeNotPersistent
                                                                                
        d = self.parent.storage.purge_node(node_id)
        d.addCallback(self._do_notify_purge, node_id)
        return d
    
    def _do_notify_purge(self, result, node_id):
        self.parent.dispatch(node_id, '//event/pubsub/purge')

class NodeDeletionService(service.Service):

    __implements__ = INodeDeletionService,

    def __init__(self):
        self._callback_list = []

    def register_pre_delete(self, pre_delete_fn):
        self._callback_list.append(pre_delete_fn)

    def get_subscribers(self, node_id):
        return self.parent.storage.get_subscribers(node_id)

    def delete_node(self, node_id, requestor):
        d1 = self.parent.storage.get_node_configuration(node_id)
        d2 = self.parent.storage.get_affiliation(node_id, requestor)
        d = defer.DeferredList([d1, d2], fireOnOneErrback=1)
        d.addErrback(lambda x: x.value[0])
        d.addCallback(self._do_pre_delete, node_id)
        return d
    
    def _do_pre_delete(self, result, node_id):
        configuration = result[0][1]
        persist_items = configuration["persist_items"]
        affiliation = result[1][1]
                                                                                
        if affiliation != 'owner':
            raise NotAuthorized

        d = defer.DeferredList([cb(node_id) for cb in self._callback_list],
                               consumeErrors=1)
        d.addCallback(self._do_delete, node_id)

    def _do_delete(self, result, node_id):
        dl = []
        for succeeded, r in result:
            if succeeded and r:
                dl.extend(r)

        d = self.parent.storage.delete_node(node_id)
        d.addCallback(self._do_notify_delete, dl)

        return d
    
    def _do_notify_delete(self, result, dl):
        for d in dl:
            d.callback(None)