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

# Copyright (c) 2012-2016 Jérôme Poisson
# Copyright (c) 2013-2016 Adrien Cossa
# Copyright (c) 2003-2011 Ralph Meijer


# 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/>.
# --

# This program is based on Idavoll (http://idavoll.ik.nu/),
# originaly written by Ralph Meijer (http://ralphm.net/blog/)
# It is sublicensed under AGPL v3 (or any later version) as allowed by the original
# license.

# --

# Here is a copy of the original license:

# Copyright (c) 2003-2011 Ralph Meijer

# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:

# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.


import copy, logging

from zope.interface import implements

from twisted.words.protocols.jabber import jid
from twisted.python import log

from wokkel import generic
from wokkel.pubsub import Subscription

from sat_pubsub import error
from sat_pubsub import iidavoll
from sat_pubsub import const
from sat_pubsub import container
import psycopg2
import psycopg2.extensions
# we wants psycopg2 to return us unicode, not str
psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
psycopg2.extensions.register_type(psycopg2.extensions.UNICODEARRAY)

# parseXml manage str, but we get unicode
parseXml = lambda unicode_data: generic.parseXml(unicode_data.encode('utf-8'))
PEP_COL_NAME = 'pep'


def withPEP(query, values, pep, recipient):
    """Helper method to facilitate PEP management

    @param query: SQL query basis
    @param values: current values to replace in query
    @param pep: True if we are in PEP mode
    @param recipient: jid of the recipient
    @return: query + PEP AND check,
        recipient's bare jid is added to value if needed
    """
    if pep:
        pep_check="AND {}=%s".format(PEP_COL_NAME)
        values=list(values) + [recipient.userhost()]
    else:
        pep_check="AND {} IS NULL".format(PEP_COL_NAME)
    return "{} {}".format(query, pep_check), values


class Storage:

    implements(iidavoll.IStorage)

    defaultConfig = {
            'leaf': {
                const.OPT_PERSIST_ITEMS: True,
                const.OPT_DELIVER_PAYLOADS: True,
                const.OPT_SEND_LAST_PUBLISHED_ITEM: 'on_sub',
                const.OPT_ACCESS_MODEL: const.VAL_AMODEL_DEFAULT,
                const.OPT_PUBLISH_MODEL: const.VAL_PMODEL_DEFAULT,
            },
            'collection': {
                const.OPT_DELIVER_PAYLOADS: True,
                const.OPT_SEND_LAST_PUBLISHED_ITEM: 'on_sub',
                const.OPT_ACCESS_MODEL: const.VAL_AMODEL_DEFAULT,
                const.OPT_PUBLISH_MODEL: const.VAL_PMODEL_DEFAULT,
            }
    }

    def __init__(self, dbpool):
        self.dbpool = dbpool

    def _buildNode(self, row):
        """Build a note class from database result row"""
        configuration = {}

        if not row:
            raise error.NodeNotFound()

        if row[2] == 'leaf':
            configuration = {
                    'pubsub#persist_items': row[3],
                    'pubsub#deliver_payloads': row[4],
                    'pubsub#send_last_published_item': row[5],
                    const.OPT_ACCESS_MODEL:row[6],
                    const.OPT_PUBLISH_MODEL:row[7],
                    }
            node = LeafNode(row[0], row[1], configuration)
            node.dbpool = self.dbpool
            return node
        elif row[2] == 'collection':
            configuration = {
                    'pubsub#deliver_payloads': row[4],
                    'pubsub#send_last_published_item': row[5],
                    const.OPT_ACCESS_MODEL: row[6],
                    const.OPT_PUBLISH_MODEL:row[7],
                    }
            node = CollectionNode(row[0], row[1], configuration)
            node.dbpool = self.dbpool
            return node
        else:
            raise ValueError("Unknown node type !")

    def getNodeById(self, nodeDbId):
        """Get node using database ID insted of pubsub identifier

        @param nodeDbId(unicode): database ID
        """
        return self.dbpool.runInteraction(self._getNodeById, nodeDbId)


    def _getNodeById(self, cursor, nodeDbId):
        cursor.execute("""SELECT node_id,
                                 node,
                                 node_type,
                                 persist_items,
                                 deliver_payloads,
                                 send_last_published_item,
                                 access_model,
                                 publish_model,
                                 pep
                            FROM nodes
                            WHERE node_id=%s""",
                       (nodeDbId,))
        row = cursor.fetchone()
        return self._buildNode(row)

    def getNode(self, nodeIdentifier, pep, recipient=None):
        return self.dbpool.runInteraction(self._getNode, nodeIdentifier, pep, recipient)


    def _getNode(self, cursor, nodeIdentifier, pep, recipient):
        cursor.execute(*withPEP("""SELECT node_id,
                                          node,
                                          node_type,
                                          persist_items,
                                          deliver_payloads,
                                          send_last_published_item,
                                          access_model,
                                          publish_model,
                                          pep
                                   FROM nodes
                                   WHERE node=%s""",
                              (nodeIdentifier,), pep, recipient))
        row = cursor.fetchone()
        return self._buildNode(row)

    def getNodeIds(self, pep):
        d = self.dbpool.runQuery("""SELECT node from nodes WHERE pep is {}NULL"""
                                    .format("NOT " if pep else ""))
        d.addCallback(lambda results: [r[0] for r in results])
        return d


    def createNode(self, nodeIdentifier, owner, config, pep, recipient=None):
        return self.dbpool.runInteraction(self._createNode, nodeIdentifier,
                                           owner, config, pep, recipient)


    def _createNode(self, cursor, nodeIdentifier, owner, config, pep, recipient):
        if config['pubsub#node_type'] != 'leaf':
            raise error.NoCollections()

        owner = owner.userhost()

        try:
            cursor.execute("""INSERT INTO nodes
                              (node, node_type, persist_items,
                               deliver_payloads, send_last_published_item, access_model, publish_model, pep)
                              VALUES
                              (%s, 'leaf', %s, %s, %s, %s, %s, %s)""",
                           (nodeIdentifier,
                            config['pubsub#persist_items'],
                            config['pubsub#deliver_payloads'],
                            config['pubsub#send_last_published_item'],
                            config[const.OPT_ACCESS_MODEL],
                            config[const.OPT_PUBLISH_MODEL],
                            recipient.userhost() if pep else None
                            )
                           )
        except cursor._pool.dbapi.IntegrityError:
            raise error.NodeExists()

        cursor.execute(*withPEP("""SELECT node_id FROM nodes WHERE node=%s""",
                                (nodeIdentifier,), pep, recipient));
        node_id = cursor.fetchone()[0]

        cursor.execute("""SELECT 1 as bool from entities where jid=%s""",
                       (owner,))

        if not cursor.fetchone():
            # XXX: we can NOT rely on the previous query! Commit is needed now because
            # if the entry exists the next query will leave the database in a corrupted
            # state: the solution is to rollback. I tried with other methods like
            # "WHERE NOT EXISTS" but none of them worked, so the following solution
            # looks like the sole - unless you have auto-commit on. More info
            # about this issue: http://cssmay.com/question/tag/tag-psycopg2
            cursor._connection.commit()
            try:
                cursor.execute("""INSERT INTO entities (jid) VALUES (%s)""",
                               (owner,))
            except psycopg2.IntegrityError as e:
                cursor._connection.rollback()
                logging.warning("during node creation: %s" % e.message)

        cursor.execute("""INSERT INTO affiliations
                          (node_id, entity_id, affiliation)
                          SELECT %s, entity_id, 'owner' FROM
                          (SELECT entity_id FROM entities
                                            WHERE jid=%s) as e""",
                       (node_id, owner))

        if config[const.OPT_ACCESS_MODEL] == const.VAL_AMODEL_PUBLISHER_ROSTER:
            if const.OPT_ROSTER_GROUPS_ALLOWED in config:
                allowed_groups = config[const.OPT_ROSTER_GROUPS_ALLOWED]
            else:
                allowed_groups = []
            for group in allowed_groups:
                #TODO: check that group are actually in roster
                cursor.execute("""INSERT INTO node_groups_authorized (node_id, groupname)
                                  VALUES (%s,%s)""" , (node_id, group))
        # XXX: affiliations can't be set on during node creation (at least not with XEP-0060 alone)
        #      so whitelist affiliations need to be done afterward

    def deleteNodeByDbId(self, db_id):
        """Delete a node using directly its database id"""
        return self.dbpool.runInteraction(self._deleteNodeByDbId, db_id)

    def _deleteNodeByDbId(self, cursor, db_id):
        cursor.execute("""DELETE FROM nodes WHERE node_id=%s""",
                       (db_id,))

        if cursor.rowcount != 1:
            raise error.NodeNotFound()

    def deleteNode(self, nodeIdentifier, pep, recipient=None):
        return self.dbpool.runInteraction(self._deleteNode, nodeIdentifier, pep, recipient)


    def _deleteNode(self, cursor, nodeIdentifier, pep, recipient):
        cursor.execute(*withPEP("""DELETE FROM nodes WHERE node=%s""",
                                (nodeIdentifier,), pep, recipient))

        if cursor.rowcount != 1:
            raise error.NodeNotFound()



    def getAffiliations(self, entity, pep, recipient=None):
        d = self.dbpool.runQuery(*withPEP("""SELECT node, affiliation FROM entities
                                        NATURAL JOIN affiliations
                                        NATURAL JOIN nodes
                                        WHERE jid=%s""",
                                     (entity.userhost(),), pep, recipient, 'nodes'))
        d.addCallback(lambda results: [tuple(r) for r in results])
        return d


    def getSubscriptions(self, entity, pep, recipient=None):
        def toSubscriptions(rows):
            subscriptions = []
            for row in rows:
                subscriber = jid.internJID('%s/%s' % (row[1],
                                                      row[2]))
                subscription = Subscription(row[0], subscriber, row[3])
                subscriptions.append(subscription)
            return subscriptions

        d = self.dbpool.runQuery("""SELECT node, jid, resource, state
                                     FROM entities
                                     NATURAL JOIN subscriptions
                                     NATURAL JOIN nodes
                                     WHERE jid=%s AND nodes.pep=%s""",
                                  (entity.userhost(), recipient.userhost() if pep else None))
        d.addCallback(toSubscriptions)
        return d


    def getDefaultConfiguration(self, nodeType):
        return self.defaultConfig[nodeType]



class Node:

    implements(iidavoll.INode)

    def __init__(self, nodeDbId, nodeIdentifier, config):
        self.nodeDbId = nodeDbId
        self.nodeIdentifier = nodeIdentifier
        self._config = config


    def _checkNodeExists(self, cursor):
        cursor.execute("""SELECT 1 as exist FROM nodes WHERE node_id=%s""",
                       (self.nodeDbId,))
        if not cursor.fetchone():
            raise error.NodeNotFound()


    def getType(self):
        return self.nodeType

    def getOwners(self):
        d = self.dbpool.runQuery("""SELECT jid FROM nodes NATURAL JOIN affiliations NATURAL JOIN entities WHERE node_id=%s and affiliation='owner'""", (self.nodeDbId,))
        d.addCallback(lambda rows: [jid.JID(r[0]) for r in rows])
        return d


    def getConfiguration(self):
        return self._config


    def setConfiguration(self, options):
        config = copy.copy(self._config)

        for option in options:
            if option in config:
                config[option] = options[option]

        d = self.dbpool.runInteraction(self._setConfiguration, config)
        d.addCallback(self._setCachedConfiguration, config)
        return d


    def _setConfiguration(self, cursor, config):
        self._checkNodeExists(cursor)
        cursor.execute("""UPDATE nodes SET persist_items=%s,
                                           deliver_payloads=%s,
                                           send_last_published_item=%s,
                                           access_model=%s,
                                           publish_model=%s
                          WHERE node_id=%s""",
                       (config[const.OPT_PERSIST_ITEMS],
                        config[const.OPT_DELIVER_PAYLOADS],
                        config[const.OPT_SEND_LAST_PUBLISHED_ITEM],
                        config[const.OPT_ACCESS_MODEL],
                        config[const.OPT_PUBLISH_MODEL],
                        self.nodeDbId))


    def _setCachedConfiguration(self, void, config):
        self._config = config


    def getMetaData(self):
        config = copy.copy(self._config)
        config["pubsub#node_type"] = self.nodeType
        return config


    def getAffiliation(self, entity):
        return self.dbpool.runInteraction(self._getAffiliation, entity)


    def _getAffiliation(self, cursor, entity):
        self._checkNodeExists(cursor)
        cursor.execute("""SELECT affiliation FROM affiliations
                          NATURAL JOIN nodes
                          NATURAL JOIN entities
                          WHERE node_id=%s AND jid=%s""",
                       (self.nodeDbId,
                        entity.userhost()))

        try:
            return cursor.fetchone()[0]
        except TypeError:
            return None


    def getAccessModel(self):
        return self._config[const.OPT_ACCESS_MODEL]


    def getSubscription(self, subscriber):
        return self.dbpool.runInteraction(self._getSubscription, subscriber)


    def _getSubscription(self, cursor, subscriber):
        self._checkNodeExists(cursor)

        userhost = subscriber.userhost()
        resource = subscriber.resource or ''

        cursor.execute("""SELECT state FROM subscriptions
                          NATURAL JOIN nodes
                          NATURAL JOIN entities
                          WHERE node_id=%s AND jid=%s AND resource=%s""",
                       (self.nodeDbId,
                        userhost,
                        resource))

        row = cursor.fetchone()
        if not row:
            return None
        else:
            return Subscription(self.nodeIdentifier, subscriber, row[0])


    def getSubscriptions(self, state=None):
        return self.dbpool.runInteraction(self._getSubscriptions, state)


    def _getSubscriptions(self, cursor, state):
        self._checkNodeExists(cursor)

        query = """SELECT node, jid, resource, state,
                          subscription_type, subscription_depth
                   FROM subscriptions
                   NATURAL JOIN nodes
                   NATURAL JOIN entities
                   WHERE node_id=%s"""
        values = [self.nodeDbId]

        if state:
            query += " AND state=%s"
            values.append(state)

        cursor.execute(query, values)
        rows = cursor.fetchall()

        subscriptions = []
        for row in rows:
            subscriber = jid.JID(u'%s/%s' % (row[1], row[2]))

            options = {}
            if row[4]:
                options['pubsub#subscription_type'] = row[4];
            if row[5]:
                options['pubsub#subscription_depth'] = row[5];

            subscriptions.append(Subscription(row[0], subscriber,
                                              row[3], options))

        return subscriptions


    def addSubscription(self, subscriber, state, config):
        return self.dbpool.runInteraction(self._addSubscription, subscriber,
                                          state, config)


    def _addSubscription(self, cursor, subscriber, state, config):
        self._checkNodeExists(cursor)

        userhost = subscriber.userhost()
        resource = subscriber.resource or ''

        subscription_type = config.get('pubsub#subscription_type')
        subscription_depth = config.get('pubsub#subscription_depth')

        try:
            cursor.execute("""INSERT INTO entities (jid) VALUES (%s)""",
                           (userhost,))
        except cursor._pool.dbapi.IntegrityError:
            cursor._connection.rollback()

        try:
            cursor.execute("""INSERT INTO subscriptions
                              (node_id, entity_id, resource, state,
                               subscription_type, subscription_depth)
                              SELECT %s, entity_id, %s, %s, %s, %s FROM
                              (SELECT entity_id FROM entities
                                                WHERE jid=%s) AS ent_id""",
                           (self.nodeDbId,
                            resource,
                            state,
                            subscription_type,
                            subscription_depth,
                            userhost))
        except cursor._pool.dbapi.IntegrityError:
            raise error.SubscriptionExists()


    def removeSubscription(self, subscriber):
        return self.dbpool.runInteraction(self._removeSubscription,
                                           subscriber)


    def _removeSubscription(self, cursor, subscriber):
        self._checkNodeExists(cursor)

        userhost = subscriber.userhost()
        resource = subscriber.resource or ''

        cursor.execute("""DELETE FROM subscriptions WHERE
                          node_id=%s AND
                          entity_id=(SELECT entity_id FROM entities
                                                      WHERE jid=%s) AND
                          resource=%s""",
                       (self.nodeDbId,
                        userhost,
                        resource))
        if cursor.rowcount != 1:
            raise error.NotSubscribed()

        return None


    def isSubscribed(self, entity):
        return self.dbpool.runInteraction(self._isSubscribed, entity)


    def _isSubscribed(self, cursor, entity):
        self._checkNodeExists(cursor)

        cursor.execute("""SELECT 1 as bool FROM entities
                          NATURAL JOIN subscriptions
                          NATURAL JOIN nodes
                          WHERE entities.jid=%s
                          AND node_id=%s AND state='subscribed'""",
                       (entity.userhost(),
                       self.nodeDbId))

        return cursor.fetchone() is not None


    def getAffiliations(self):
        return self.dbpool.runInteraction(self._getAffiliations)


    def _getAffiliations(self, cursor):
        self._checkNodeExists(cursor)

        cursor.execute("""SELECT jid, affiliation FROM nodes
                          NATURAL JOIN affiliations
                          NATURAL JOIN entities
                          WHERE node_id=%s""",
                       (self.nodeDbId,))
        result = cursor.fetchall()

        return {jid.internJID(r[0]): r[1] for r in result}



class LeafNode(Node):

    implements(iidavoll.ILeafNode)

    nodeType = 'leaf'

    def storeItems(self, item_data, publisher):
        return self.dbpool.runInteraction(self._storeItems, item_data, publisher)

    def _storeItems(self, cursor, items_data, publisher):
        self._checkNodeExists(cursor)
        for item_data in items_data:
            self._storeItem(cursor, item_data, publisher)

    def _storeItem(self, cursor, item_data, publisher):
        item, access_model, item_config = item_data.item, item_data.access_model, item_data.config
        data = item.toXml()

        cursor.execute("""UPDATE items SET date=now(), publisher=%s, data=%s
                          FROM nodes
                          WHERE nodes.node_id = items.node_id AND
                                nodes.node_id = %s and items.item=%s
                          RETURNING item_id""",
                       (publisher.full(),
                        data,
                        self.nodeDbId,
                        item["id"]))
        if cursor.rowcount == 1:
            item_id = cursor.fetchone()[0];
            self._storeCategories(cursor, item_id, item_data.categories, update=True)
            return

        cursor.execute("""INSERT INTO items (node_id, item, publisher, data, access_model)
                          SELECT %s, %s, %s, %s, %s FROM nodes
                                                     WHERE node_id=%s
                                                     RETURNING item_id""",
                       (self.nodeDbId,
                        item["id"],
                        publisher.full(),
                        data,
                        access_model,
                        self.nodeDbId))

        item_id = cursor.fetchone()[0];
        self._storeCategories(cursor, item_id, item_data.categories)

        if access_model == const.VAL_AMODEL_PUBLISHER_ROSTER:
            if const.OPT_ROSTER_GROUPS_ALLOWED in item_config:
                item_config.fields[const.OPT_ROSTER_GROUPS_ALLOWED].fieldType='list-multi' #XXX: needed to force list if there is only one value
                allowed_groups = item_config[const.OPT_ROSTER_GROUPS_ALLOWED]
            else:
                allowed_groups = []
            for group in allowed_groups:
                #TODO: check that group are actually in roster
                cursor.execute("""INSERT INTO item_groups_authorized (item_id, groupname)
                                  VALUES (%s,%s)""" , (item_id, group))
        # TODO: whitelist access model

    def _storeCategories(self, cursor, item_id, categories, update=False):
        # TODO: handle canonical form
        if update:
            cursor.execute("""DELETE FROM item_categories
                              WHERE item_id=%s""", (item_id,))

        for category in categories:
            cursor.execute("""INSERT INTO item_categories (item_id, category)
                              VALUES (%s, %s)""", (item_id, category))

    def removeItems(self, itemIdentifiers):
        return self.dbpool.runInteraction(self._removeItems, itemIdentifiers)

    def _removeItems(self, cursor, itemIdentifiers):
        self._checkNodeExists(cursor)

        deleted = []

        for itemIdentifier in itemIdentifiers:
            cursor.execute("""DELETE FROM items WHERE
                              node_id=%s AND
                              item=%s""",
                           (self.nodeDbId,
                            itemIdentifier))

            if cursor.rowcount:
                deleted.append(itemIdentifier)

        return deleted

    def getItems(self, authorized_groups, unrestricted, maxItems=None, ext_data=None):
        """ Get all authorised items
        @param authorized_groups: we want to get items that these groups can access
        @param unrestricted: if true, don't check permissions (i.e.: get all items)
        @param maxItems: nb of items we want to get
        @param ext_data: options for extra features like RSM and MAM

        @return: list of container.ItemData
            if unrestricted is False, access_model and config will be None
        """
        if ext_data is None:
            ext_data = {}
        return self.dbpool.runInteraction(self._getItems, authorized_groups, unrestricted, maxItems, ext_data)

    def _appendSourcesAndFilters(self, query, args, authorized_groups, unrestricted, ext_data):
        """append sources and filters to sql query requesting items and return ORDER BY

        arguments query, args, authorized_groups, unrestricted and ext_data are the same as for
        _getItems
        """
        # SOURCES
        query.append("FROM nodes INNER JOIN items USING (node_id)")

        if unrestricted:
            query_filters = ["WHERE node_id=%s"]
            args.append(self.nodeDbId)
        else:
            query.append("LEFT JOIN item_groups_authorized USING (item_id)")
            args.append(self.nodeDbId)
            if authorized_groups:
                get_groups = " or (items.access_model='roster' and groupname in %s)"
                args.append(authorized_groups)
            else:
                get_groups = ""

            query_filters = ["WHERE node_id=%s AND (items.access_model='open'" + get_groups + ")"]

        # FILTERS
        if 'filters' in ext_data:  # MAM filters
            for filter_ in ext_data['filters']:
                if filter_.var == 'start':
                    query_filters.append("AND date>=%s")
                    args.append(filter_.value)
                elif filter_.var == 'end':
                    query_filters.append("AND date<=%s")
                    args.append(filter_.value)
                elif filter_.var == 'with':
                    jid_s = filter_.value
                    if '/' in jid_s:
                        query_filters.append("AND publisher=%s")
                        args.append(filter_.value)
                    else:
                        query_filters.append("AND publisher LIKE %s")
                        args.append(u"{}%".format(filter_.value))
                elif filter_.var == const.MAM_FILTER_CATEGORY:
                    query.append("LEFT JOIN item_categories USING (item_id)")
                    query_filters.append("AND category=%s")
                    args.append(filter_.value)
                else:
                    log.msg("WARNING: unknown filter: {}".format(filter_.encode('utf-8')))

        query.extend(query_filters)

        return "ORDER BY item_id DESC"

    def _getItems(self, cursor, authorized_groups, unrestricted, maxItems, ext_data):
        self._checkNodeExists(cursor)

        if maxItems == 0:
            return []

        args = []

        # SELECT
        query = ["SELECT data,items.access_model,item_id,date"]

        query_order = self._appendSourcesAndFilters(query, args, authorized_groups, unrestricted, ext_data)

        if 'rsm' in ext_data:
            rsm = ext_data['rsm']
            maxItems = rsm.max
            if rsm.index is not None:
                # We need to know the item_id of corresponding to the index (offset) of the current query
                # so we execute the query to look for the item_id
                tmp_query = query[:]
                tmp_args = args[:]
                tmp_query[0] = "SELECT item_id"
                tmp_query.append("{} LIMIT 1 OFFSET %s".format(query_order))
                tmp_args.append(rsm.index)
                cursor.execute(' '.join(query), args)
                # FIXME: bad index is not managed yet
                item_id = cursor.fetchall()[0][0]

                # now that we have the id, we can use it
                query.append("AND item_id<=%s")
                args.append(item_id)
            elif rsm.before is not None:
                if rsm.before != '':
                    query.append("AND item_id>(SELECT item_id FROM items WHERE item=%s LIMIT 1)")
                    args.append(rsm.before)
                if maxItems is not None:
                    # if we have maxItems (i.e. a limit), we need to reverse order
                    # in a first query to get the right items
                    query.insert(0,"SELECT * from (")
                    query.append("ORDER BY item_id ASC LIMIT %s) as x")
                    args.append(maxItems)
            elif rsm.after:
                query.append("AND item_id<(SELECT item_id FROM items WHERE item=%s LIMIT 1)")
                args.append(rsm.after)

        query.append(query_order)

        if maxItems is not None:
            query.append("LIMIT %s")
            args.append(maxItems)

        cursor.execute(' '.join(query), args)

        result = cursor.fetchall()
        if unrestricted:
            # with unrestricted query, we need to fill the access_list for a roster access items
            ret = []
            for data in result:
                item = generic.stripNamespace(parseXml(data[0]))
                access_model = data[1]
                item_id = data[2]
                date = data[3]
                access_list = {}
                if access_model == const.VAL_AMODEL_PUBLISHER_ROSTER:
                    cursor.execute('SELECT groupname FROM item_groups_authorized WHERE item_id=%s', (item_id,))
                    access_list[const.OPT_ROSTER_GROUPS_ALLOWED] = [r[0] for r in cursor.fetchall()]

                ret.append(container.ItemData(item, access_model, access_list, date=date))
                # TODO: whitelist item access model
            return ret

        items_data = [container.ItemData(generic.stripNamespace(parseXml(r[0])), r[1], r[2], date=r[3]) for r in result]
        return items_data

    def getItemsById(self, authorized_groups, unrestricted, itemIdentifiers):
        """Get items which are in the given list

        @param authorized_groups: we want to get items that these groups can access
        @param unrestricted: if true, don't check permissions
        @param itemIdentifiers: list of ids of the items we want to get
        @return: list of container.ItemData
            ItemData.config will contains access_list (managed as a dictionnary with same key as for item_config)
            if unrestricted is False, access_model and config will be None
        """
        return self.dbpool.runInteraction(self._getItemsById, authorized_groups, unrestricted, itemIdentifiers)

    def _getItemsById(self, cursor, authorized_groups, unrestricted, itemIdentifiers):
        self._checkNodeExists(cursor)
        ret = []
        if unrestricted: #we get everything without checking permissions
            for itemIdentifier in itemIdentifiers:
                cursor.execute("""SELECT data,items.access_model,item_id,date FROM nodes
                                  INNER JOIN items USING (node_id)
                                  WHERE node_id=%s AND item=%s""",
                               (self.nodeDbId,
                                itemIdentifier))
                result = cursor.fetchone()
                if not result:
                    raise error.ItemNotFound()

                item = generic.stripNamespace(parseXml(result[0]))
                access_model = result[1]
                item_id = result[2]
                date= result[3]
                access_list = {}
                if access_model == const.VAL_AMODEL_PUBLISHER_ROSTER:
                    cursor.execute('SELECT groupname FROM item_groups_authorized WHERE item_id=%s', (item_id,))
                    access_list[const.OPT_ROSTER_GROUPS_ALLOWED] = [r[0] for r in cursor.fetchall()]
                 #TODO: WHITELIST access_model

                ret.append(container.ItemData(item, access_model, access_list, date=date))
        else: #we check permission before returning items
            for itemIdentifier in itemIdentifiers:
                args = [self.nodeDbId, itemIdentifier]
                if authorized_groups:
                    args.append(authorized_groups)
                cursor.execute("""SELECT data, date FROM nodes
                           INNER  JOIN items USING (node_id)
                           LEFT JOIN item_groups_authorized USING (item_id)
                           WHERE node_id=%s AND item=%s AND
                           (items.access_model='open' """ +
                           ("or (items.access_model='roster' and groupname in %s)" if authorized_groups else '') + ")",
                           args)

                result = cursor.fetchone()
                if result:
                    ret.append(container.ItemData(generic.stripNamespace(parseXml(result[0])), date=result[1]))

        return ret

    def getItemsCount(self, authorized_groups, unrestricted, ext_data=None):
        """Count expected number of items in a getItems query

        @param authorized_groups: we want to get items that these groups can access
        @param unrestricted: if true, don't check permissions (i.e.: get all items)
        @param ext_data: options for extra features like RSM and MAM
        """
        if ext_data is None:
            ext_data = {}
        return self.dbpool.runInteraction(self._getItemsCount, authorized_groups, unrestricted, ext_data)

    def _getItemsCount(self, cursor, authorized_groups, unrestricted, ext_data):
        self._checkNodeExists(cursor)
        args = []

        # SELECT
        query = ["SELECT count(1)"]

        self._appendSourcesAndFilters(query, args, authorized_groups, unrestricted, ext_data)

        cursor.execute(' '.join(query), args)
        return cursor.fetchall()[0][0]

    def getItemsIndex(self, item_id, authorized_groups, unrestricted, ext_data=None):
        """Get expected index of first item in the window of a getItems query

        @param item_id: id of the item
        @param authorized_groups: we want to get items that these groups can access
        @param unrestricted: if true, don't check permissions (i.e.: get all items)
        @param ext_data: options for extra features like RSM and MAM
        """
        if ext_data is None:
            ext_data = {}
        return self.dbpool.runInteraction(self._getItemsIndex, item_id, authorized_groups, unrestricted, ext_data)

    def _getItemsIndex(self, cursor, item_id, authorized_groups, unrestricted, ext_data):
        self._checkNodeExists(cursor)
        args = []

        # SELECT
        query = []

        query_order = self._appendSourcesAndFilters(query, args, authorized_groups, unrestricted, ext_data)

        query_select = "SELECT row_number from (SELECT row_number() OVER ({}), item".format(query_order)
        query.insert(0, query_select)
        query.append(") as x WHERE item=%s")
        args.append(item_id)

        cursor.execute(' '.join(query), args)
        # XXX: row_number start at 1, but we want that index start at 0
        try:
            return cursor.fetchall()[0][0] - 1
        except IndexError:
            raise error.NodeNotFound()

    def getItemsPublishers(self, itemIdentifiers):
        """Get the publishers for all given identifiers

        @return (dict[unicode, jid.JID]): map of itemIdentifiers to publisher
            if item is not found, key is skipped in resulting dict
        """
        return self.dbpool.runInteraction(self._getItemsPublishers, itemIdentifiers)

    def _getItemsPublishers(self, cursor, itemIdentifiers):
        self._checkNodeExists(cursor)
        ret = {}
        for itemIdentifier in itemIdentifiers:
            cursor.execute("""SELECT publisher FROM items
                              WHERE item=%s""",
                            (itemIdentifier,))
            result = cursor.fetchone()
            if result:
                ret[itemIdentifier] = jid.JID(result[0])
        return ret

    def purge(self):
        return self.dbpool.runInteraction(self._purge)

    def _purge(self, cursor):
        self._checkNodeExists(cursor)

        cursor.execute("""DELETE FROM items WHERE
                          node_id=%s""",
                       (self.nodeDbId,))


class CollectionNode(Node):

    nodeType = 'collection'



class GatewayStorage(object):
    """
    Memory based storage facility for the XMPP-HTTP gateway.
    """

    def __init__(self, dbpool):
        self.dbpool = dbpool


    def _countCallbacks(self, cursor, service, nodeIdentifier):
        """
        Count number of callbacks registered for a node.
        """
        cursor.execute("""SELECT count(*) FROM callbacks
                          WHERE service=%s and node=%s""",
                       (service.full(),
                        nodeIdentifier))
        results = cursor.fetchall()
        return results[0][0]


    def addCallback(self, service, nodeIdentifier, callback):
        def interaction(cursor):
            cursor.execute("""SELECT 1 as bool FROM callbacks
                              WHERE service=%s and node=%s and uri=%s""",
                           (service.full(),
                           nodeIdentifier,
                           callback))
            if cursor.fetchall():
                return

            cursor.execute("""INSERT INTO callbacks
                              (service, node, uri) VALUES
                              (%s, %s, %s)""",
                           (service.full(),
                           nodeIdentifier,
                           callback))

        return self.dbpool.runInteraction(interaction)


    def removeCallback(self, service, nodeIdentifier, callback):
        def interaction(cursor):
            cursor.execute("""DELETE FROM callbacks
                              WHERE service=%s and node=%s and uri=%s""",
                           (service.full(),
                            nodeIdentifier,
                            callback))

            if cursor.rowcount != 1:
                raise error.NotSubscribed()

            last = not self._countCallbacks(cursor, service, nodeIdentifier)
            return last

        return self.dbpool.runInteraction(interaction)

    def getCallbacks(self, service, nodeIdentifier):
        def interaction(cursor):
            cursor.execute("""SELECT uri FROM callbacks
                              WHERE service=%s and node=%s""",
                           (service.full(),
                            nodeIdentifier))
            results = cursor.fetchall()

            if not results:
                raise error.NoCallbacks()

            return [result[0] for result in results]

        return self.dbpool.runInteraction(interaction)


    def hasCallbacks(self, service, nodeIdentifier):
        def interaction(cursor):
            return bool(self._countCallbacks(cursor, service, nodeIdentifier))

        return self.dbpool.runInteraction(interaction)