# -*- coding:utf-8 -*-
## src/common/logger.py
##
## Copyright (C) 2003-2010 Yann Leboulanger <asterix AT lagaule.org>
## Copyright (C) 2004-2005 Vincent Hanquez <tab AT snarc.org>
## Copyright (C) 2005-2006 Nikos Kouremenos <kourem AT gmail.com>
## Copyright (C) 2006 Dimitur Kirov <dkirov AT gmail.com>
## Copyright (C) 2006-2008 Jean-Marie Traissard <jim AT lapin.org>
## Copyright (C) 2007 Tomasz Melcer <liori AT exroot.org>
##                    Julien Pivotto <roidelapluie AT gmail.com>
##
## This file is part of Gajim.
##
## Gajim is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published
## by the Free Software Foundation; version 3 only.
##
## Gajim 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 General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Gajim. If not, see <http://www.gnu.org/licenses/>.
##

"""
This module allows to access the on-disk database of logs
"""

import os
import sys
import time
import datetime
from gzip import GzipFile
from cStringIO import StringIO

import exceptions
import gajim

import sqlite3 as sqlite

import configpaths
LOG_DB_PATH = configpaths.gajimpaths['LOG_DB']
LOG_DB_FOLDER, LOG_DB_FILE = os.path.split(LOG_DB_PATH)
CACHE_DB_PATH = configpaths.gajimpaths['CACHE_DB']

import logging
log = logging.getLogger('gajim.c.logger')

class Constants:
    def __init__(self):
        (
                self.JID_NORMAL_TYPE,
                self.JID_ROOM_TYPE
        ) = range(2)

        (
                self.KIND_STATUS,
                self.KIND_GCSTATUS,
                self.KIND_GC_MSG,
                self.KIND_SINGLE_MSG_RECV,
                self.KIND_CHAT_MSG_RECV,
                self.KIND_SINGLE_MSG_SENT,
                self.KIND_CHAT_MSG_SENT,
                self.KIND_ERROR
        ) = range(8)

        (
                self.SHOW_ONLINE,
                self.SHOW_CHAT,
                self.SHOW_AWAY,
                self.SHOW_XA,
                self.SHOW_DND,
                self.SHOW_OFFLINE
        ) = range(6)

        (
                self.TYPE_AIM,
                self.TYPE_GG,
                self.TYPE_HTTP_WS,
                self.TYPE_ICQ,
                self.TYPE_MSN,
                self.TYPE_QQ,
                self.TYPE_SMS,
                self.TYPE_SMTP,
                self.TYPE_TLEN,
                self.TYPE_YAHOO,
                self.TYPE_NEWMAIL,
                self.TYPE_RSS,
                self.TYPE_WEATHER,
                self.TYPE_MRIM,
        ) = range(14)

        (
                self.SUBSCRIPTION_NONE,
                self.SUBSCRIPTION_TO,
                self.SUBSCRIPTION_FROM,
                self.SUBSCRIPTION_BOTH,
        ) = range(4)

constants = Constants()

class Logger:
    def __init__(self):
        self.jids_already_in = [] # holds jids that we already have in DB
        self.con = None

        if not os.path.exists(LOG_DB_PATH):
            # this can happen only the first time (the time we create the db)
            # db is not created here but in src/common/checks_paths.py
            return
        self.init_vars()
        if not os.path.exists(CACHE_DB_PATH):
            # this can happen cache database is not present when gajim is launched
            # db will be created in src/common/checks_paths.py
            return
        self.attach_cache_database()

    def close_db(self):
        if self.con:
            self.con.close()
        self.con = None
        self.cur = None

    def open_db(self):
        self.close_db()

        # FIXME: sqlite3_open wants UTF8 strings. So a path with
        # non-ascii chars doesn't work. See #2812 and
        # http://lists.initd.org/pipermail/pysqlite/2005-August/000134.html
        back = os.getcwd()
        os.chdir(LOG_DB_FOLDER)

        # if locked, wait up to 20 sec to unlock
        # before raise (hopefully should be enough)

        self.con = sqlite.connect(LOG_DB_FILE, timeout=20.0,
                isolation_level='IMMEDIATE')
        os.chdir(back)
        self.cur = self.con.cursor()
        self.set_synchronous(False)

    def attach_cache_database(self):
        try:
            self.cur.execute("ATTACH DATABASE '%s' AS cache" % CACHE_DB_PATH)
        except sqlite.Error, e:
            log.debug("Failed to attach cache database: %s" % str(e))

    def set_synchronous(self, sync):
        try:
            if sync:
                self.cur.execute("PRAGMA synchronous = NORMAL")
            else:
                self.cur.execute("PRAGMA synchronous = OFF")
        except sqlite.Error, e:
            log.debug("Failed to set_synchronous(%s): %s" % (sync, str(e)))

    def init_vars(self):
        self.open_db()
        self.get_jids_already_in_db()

    def simple_commit(self, sql_to_commit):
        """
        Helper to commit
        """
        self.cur.execute(sql_to_commit)
        try:
            self.con.commit()
        except sqlite.OperationalError, e:
            print >> sys.stderr, str(e)

    def get_jids_already_in_db(self):
        try:
            self.cur.execute('SELECT jid FROM jids')
            # list of tupples: [(u'aaa@bbb',), (u'cc@dd',)]
            rows = self.cur.fetchall()
        except sqlite.DatabaseError:
            raise exceptions.DatabaseMalformed
        self.jids_already_in = []
        for row in rows:
            # row[0] is first item of row (the only result here, the jid)
            if row[0] == '':
                # malformed jid, ignore line
                pass
            else:
                self.jids_already_in.append(row[0])

    def get_jids_in_db(self):
        return self.jids_already_in

    def jid_is_from_pm(self, jid):
        """
        If jid is gajim@conf/nkour it's likely a pm one, how we know gajim@conf
        is not a normal guy and nkour is not his resource?  we ask if gajim@conf
        is already in jids (with type room jid) this fails if user disables
        logging for room and only enables for pm (so higly unlikely) and if we
        fail we do not go chaos (user will see the first pm as if it was message
        in room's public chat) and after that all okay
        """
        if jid.find('/') > -1:
            possible_room_jid = jid.split('/', 1)[0]
            return self.jid_is_room_jid(possible_room_jid)
        else:
            # it's not a full jid, so it's not a pm one
            return False

    def jid_is_room_jid(self, jid):
        self.cur.execute('SELECT jid_id FROM jids WHERE jid=?  AND type=?',
                (jid, constants.JID_ROOM_TYPE))
        row = self.cur.fetchone()
        if row is None:
            return False
        else:
            return True

    def get_jid_id(self, jid, typestr=None):
        """
        jids table has jid and jid_id logs table has log_id, jid_id,
        contact_name, time, kind, show, message so to ask logs we need jid_id
        that matches our jid in jids table this method wants jid and returns the
        jid_id for later sql-ing on logs typestr can be 'ROOM' or anything else
        depending on the type of JID and is only needed to be specified when the
        JID is new in DB
        """
        if jid.find('/') != -1: # if it has a /
            jid_is_from_pm = self.jid_is_from_pm(jid)
            if not jid_is_from_pm: # it's normal jid with resource
                jid = jid.split('/', 1)[0] # remove the resource
        if jid in self.jids_already_in: # we already have jids in DB
            self.cur.execute('SELECT jid_id FROM jids WHERE jid=?', [jid])
            row = self.cur.fetchone()
            if row:
                return row[0]
        # oh! a new jid :), we add it now
        if typestr == 'ROOM':
            typ = constants.JID_ROOM_TYPE
        else:
            typ = constants.JID_NORMAL_TYPE
        try:
            self.cur.execute('INSERT INTO jids (jid, type) VALUES (?, ?)', (jid,
                    typ))
            self.con.commit()
        except sqlite.IntegrityError, e:
            # Jid already in DB, maybe added by another instance. re-read DB
            self.get_jids_already_in_db()
            return self.get_jid_id(jid, typestr)
        except sqlite.OperationalError, e:
            raise exceptions.PysqliteOperationalError(str(e))
        jid_id = self.cur.lastrowid
        self.jids_already_in.append(jid)
        return jid_id

    def convert_human_values_to_db_api_values(self, kind, show):
        """
        Convert from string style to constant ints for db
        """
        if kind == 'status':
            kind_col = constants.KIND_STATUS
        elif kind == 'gcstatus':
            kind_col = constants.KIND_GCSTATUS
        elif kind == 'gc_msg':
            kind_col = constants.KIND_GC_MSG
        elif kind == 'single_msg_recv':
            kind_col = constants.KIND_SINGLE_MSG_RECV
        elif kind == 'single_msg_sent':
            kind_col = constants.KIND_SINGLE_MSG_SENT
        elif kind == 'chat_msg_recv':
            kind_col = constants.KIND_CHAT_MSG_RECV
        elif kind == 'chat_msg_sent':
            kind_col = constants.KIND_CHAT_MSG_SENT
        elif kind == 'error':
            kind_col = constants.KIND_ERROR

        if show == 'online':
            show_col = constants.SHOW_ONLINE
        elif show == 'chat':
            show_col = constants.SHOW_CHAT
        elif show == 'away':
            show_col = constants.SHOW_AWAY
        elif show == 'xa':
            show_col = constants.SHOW_XA
        elif show == 'dnd':
            show_col = constants.SHOW_DND
        elif show == 'offline':
            show_col = constants.SHOW_OFFLINE
        elif show is None:
            show_col = None
        else: # invisible in GC when someone goes invisible
            # it's a RFC violation .... but we should not crash
            show_col = 'UNKNOWN'

        return kind_col, show_col

    def convert_human_transport_type_to_db_api_values(self, type_):
        """
        Convert from string style to constant ints for db
        """
        if type_ == 'aim':
            return constants.TYPE_AIM
        if type_ == 'gadu-gadu':
            return constants.TYPE_GG
        if type_ == 'http-ws':
            return constants.TYPE_HTTP_WS
        if type_ == 'icq':
            return constants.TYPE_ICQ
        if type_ == 'msn':
            return constants.TYPE_MSN
        if type_ == 'qq':
            return constants.TYPE_QQ
        if type_ == 'sms':
            return constants.TYPE_SMS
        if type_ == 'smtp':
            return constants.TYPE_SMTP
        if type_ in ('tlen', 'x-tlen'):
            return constants.TYPE_TLEN
        if type_ == 'yahoo':
            return constants.TYPE_YAHOO
        if type_ == 'newmail':
            return constants.TYPE_NEWMAIL
        if type_ == 'rss':
            return constants.TYPE_RSS
        if type_ == 'weather':
            return constants.TYPE_WEATHER
        if type_ == 'mrim':
            return constants.TYPE_MRIM
        return None

    def convert_api_values_to_human_transport_type(self, type_id):
        """
        Convert from constant ints for db to string style
        """
        if type_id == constants.TYPE_AIM:
            return 'aim'
        if type_id == constants.TYPE_GG:
            return 'gadu-gadu'
        if type_id == constants.TYPE_HTTP_WS:
            return 'http-ws'
        if type_id == constants.TYPE_ICQ:
            return 'icq'
        if type_id == constants.TYPE_MSN:
            return 'msn'
        if type_id == constants.TYPE_QQ:
            return 'qq'
        if type_id == constants.TYPE_SMS:
            return 'sms'
        if type_id == constants.TYPE_SMTP:
            return 'smtp'
        if type_id == constants.TYPE_TLEN:
            return 'tlen'
        if type_id == constants.TYPE_YAHOO:
            return 'yahoo'
        if type_id == constants.TYPE_NEWMAIL:
            return 'newmail'
        if type_id == constants.TYPE_RSS:
            return 'rss'
        if type_id == constants.TYPE_WEATHER:
            return 'weather'
        if type_id == constants.TYPE_MRIM:
            return 'mrim'

    def convert_human_subscription_values_to_db_api_values(self, sub):
        """
        Convert from string style to constant ints for db
        """
        if sub == 'none':
            return constants.SUBSCRIPTION_NONE
        if sub == 'to':
            return constants.SUBSCRIPTION_TO
        if sub == 'from':
            return constants.SUBSCRIPTION_FROM
        if sub == 'both':
            return constants.SUBSCRIPTION_BOTH

    def convert_db_api_values_to_human_subscription_values(self, sub):
        """
        Convert from constant ints for db to string style
        """
        if sub == constants.SUBSCRIPTION_NONE:
            return 'none'
        if sub == constants.SUBSCRIPTION_TO:
            return 'to'
        if sub == constants.SUBSCRIPTION_FROM:
            return 'from'
        if sub == constants.SUBSCRIPTION_BOTH:
            return 'both'

    def commit_to_db(self, values, write_unread=False):
        sql = '''INSERT INTO logs (jid_id, contact_name, time, kind, show,
                message, subject) VALUES (?, ?, ?, ?, ?, ?, ?)'''
        try:
            self.cur.execute(sql, values)
        except sqlite.DatabaseError:
            raise exceptions.DatabaseMalformed
        except sqlite.OperationalError, e:
            raise exceptions.PysqliteOperationalError(str(e))
        message_id = None
        try:
            self.con.commit()
            if write_unread:
                message_id = self.cur.lastrowid
        except sqlite.OperationalError, e:
            print >> sys.stderr, str(e)
        if message_id:
            self.insert_unread_events(message_id, values[0])
        return message_id

    def insert_unread_events(self, message_id, jid_id):
        """
        Add unread message with id: message_id
        """
        sql = 'INSERT INTO unread_messages VALUES (%d, %d, 0)' % (message_id,
                jid_id)
        self.simple_commit(sql)

    def set_read_messages(self, message_ids):
        """
        Mark all messages with ids in message_ids as read
        """
        ids = ','.join([str(i) for i in message_ids])
        sql = 'DELETE FROM unread_messages WHERE message_id IN (%s)' % ids
        self.simple_commit(sql)

    def set_shown_unread_msgs(self, msg_id):
        """
        Mark unread message as shown un GUI
        """
        sql = 'UPDATE unread_messages SET shown = 1 where message_id = %s' % \
                msg_id
        self.simple_commit(sql)

    def reset_shown_unread_messages(self):
        """
        Set shown field to False in unread_messages table
        """
        sql = 'UPDATE unread_messages SET shown = 0'
        self.simple_commit(sql)

    def get_unread_msgs(self):
        """
        Get all unread messages
        """
        all_messages = []
        try:
            self.cur.execute(
                    'SELECT message_id, shown from unread_messages')
            results = self.cur.fetchall()
        except Exception:
            pass
        for message in results:
            msg_id = message[0]
            shown = message[1]
            # here we get infos for that message, and related jid from jids table
            # do NOT change order of SELECTed things, unless you change function(s)
            # that called this function
            self.cur.execute('''
                    SELECT logs.log_line_id, logs.message, logs.time, logs.subject,
                    jids.jid
                    FROM logs, jids
                    WHERE logs.log_line_id = %d AND logs.jid_id = jids.jid_id
                    ''' % msg_id
                    )
            results = self.cur.fetchall()
            if len(results) == 0:
                # Log line is no more in logs table. remove it from unread_messages
                self.set_read_messages([msg_id])
                continue
            all_messages.append(results[0] + (shown,))
        return all_messages

    def write(self, kind, jid, message=None, show=None, tim=None, subject=None):
        """
        Write a row (status, gcstatus, message etc) to logs database

        kind can be status, gcstatus, gc_msg, (we only recv for those 3),
        single_msg_recv, chat_msg_recv, chat_msg_sent, single_msg_sent we cannot
        know if it is pm or normal chat message, we try to guess see
        jid_is_from_pm()

        We analyze jid and store it as follows:
                jids.jid text column will hold JID if TC-related, room_jid if GC-related,
                ROOM_JID/nick if pm-related.
        """

        if self.jids_already_in == []: # only happens if we just created the db
            self.open_db()

        contact_name_col = None # holds nickname for kinds gcstatus, gc_msg
        # message holds the message unless kind is status or gcstatus,
        # then it holds status message
        message_col = message
        subject_col = subject
        if tim:
            time_col = int(float(time.mktime(tim)))
        else:
            time_col = int(float(time.time()))

        kind_col, show_col = self.convert_human_values_to_db_api_values(kind,
                show)

        write_unread = False

        # now we may have need to do extra care for some values in columns
        if kind == 'status': # we store (not None) time, jid, show, msg
            # status for roster items
            try:
                jid_id = self.get_jid_id(jid)
            except exceptions.PysqliteOperationalError, e:
                raise exceptions.PysqliteOperationalError(str(e))
            if show is None: # show is None (xmpp), but we say that 'online'
                show_col = constants.SHOW_ONLINE

        elif kind == 'gcstatus':
            # status in ROOM (for pm status see status)
            if show is None: # show is None (xmpp), but we say that 'online'
                show_col = constants.SHOW_ONLINE
            jid, nick = jid.split('/', 1)
            try:
                # re-get jid_id for the new jid
                jid_id = self.get_jid_id(jid, 'ROOM')
            except exceptions.PysqliteOperationalError, e:
                raise exceptions.PysqliteOperationalError(str(e))
            contact_name_col = nick

        elif kind == 'gc_msg':
            if jid.find('/') != -1: # if it has a /
                jid, nick = jid.split('/', 1)
            else:
                # it's server message f.e. error message
                # when user tries to ban someone but he's not allowed to
                nick = None
            try:
                # re-get jid_id for the new jid
                jid_id = self.get_jid_id(jid, 'ROOM')
            except exceptions.PysqliteOperationalError, e:
                raise exceptions.PysqliteOperationalError(str(e))
            contact_name_col = nick
        else:
            try:
                jid_id = self.get_jid_id(jid)
            except exceptions.PysqliteOperationalError, e:
                raise exceptions.PysqliteOperationalError(str(e))
            if kind == 'chat_msg_recv':
                if not self.jid_is_from_pm(jid):
                    # Save in unread table only if it's not a pm
                    write_unread = True

        if show_col == 'UNKNOWN': # unknown show, do not log
            return

        values = (jid_id, contact_name_col, time_col, kind_col, show_col,
                message_col, subject_col)
        return self.commit_to_db(values, write_unread)

    def get_last_conversation_lines(self, jid, restore_how_many_rows,
                    pending_how_many, timeout, account):
        """
        Accept how many rows to restore and when to time them out (in minutes)
        (mark them as too old) and number of messages that are in queue and are
        already logged but pending to be viewed, returns a list of tupples
        containg time, kind, message, list with empty tupple if nothing found to
        meet our demands
        """
        try:
            self.get_jid_id(jid)
        except exceptions.PysqliteOperationalError, e:
            # Error trying to create a new jid_id. This means there is no log
            return []
        where_sql = self._build_contact_where(account, jid)

        now = int(float(time.time()))
        timed_out = now - (timeout * 60) # before that they are too old
        # so if we ask last 5 lines and we have 2 pending we get
        # 3 - 8 (we avoid the last 2 lines but we still return 5 asked)
        try:
            self.cur.execute('''
                    SELECT time, kind, message FROM logs
                    WHERE (%s) AND kind IN (%d, %d, %d, %d, %d) AND time > %d
                    ORDER BY time DESC LIMIT %d OFFSET %d
                    ''' % (where_sql, constants.KIND_SINGLE_MSG_RECV,
                            constants.KIND_CHAT_MSG_RECV, constants.KIND_SINGLE_MSG_SENT,
                            constants.KIND_CHAT_MSG_SENT, constants.KIND_ERROR,
                            timed_out, restore_how_many_rows, pending_how_many)
                    )

            results = self.cur.fetchall()
        except sqlite.DatabaseError:
            raise exceptions.DatabaseMalformed
        results.reverse()
        return results

    def get_unix_time_from_date(self, year, month, day):
        # year (fe 2005), month (fe 11), day (fe 25)
        # returns time in seconds for the second that starts that date since epoch
        # gimme unixtime from year month day:
        d = datetime.date(year, month, day)
        local_time = d.timetuple() # time tupple (compat with time.localtime())
        # we have time since epoch baby :)
        start_of_day = int(time.mktime(local_time))
        return start_of_day

    def get_conversation_for_date(self, jid, year, month, day, account):
        """
        Return contact_name, time, kind, show, message, subject

        For each row in a list of tupples, returns list with empty tupple if we
        found nothing to meet our demands
        """
        try:
            self.get_jid_id(jid)
        except exceptions.PysqliteOperationalError, e:
            # Error trying to create a new jid_id. This means there is no log
            return []
        where_sql = self._build_contact_where(account, jid)

        start_of_day = self.get_unix_time_from_date(year, month, day)
        seconds_in_a_day = 86400 # 60 * 60 * 24
        last_second_of_day = start_of_day + seconds_in_a_day - 1

        self.cur.execute('''
                SELECT contact_name, time, kind, show, message, subject FROM logs
                WHERE (%s)
                AND time BETWEEN %d AND %d
                ORDER BY time
                ''' % (where_sql, start_of_day, last_second_of_day))

        results = self.cur.fetchall()
        return results

    def get_search_results_for_query(self, jid, query, account):
        """
        Returns contact_name, time, kind, show, message

        For each row in a list of tupples, returns list with empty tupple if we
        found nothing to meet our demands
        """
        try:
            self.get_jid_id(jid)
        except exceptions.PysqliteOperationalError, e:
            # Error trying to create a new jid_id. This means there is no log
            return []

        if False: # query.startswith('SELECT '): # it's SQL query (FIXME)
            try:
                self.cur.execute(query)
            except sqlite.OperationalError, e:
                results = [('', '', '', '', str(e))]
                return results

        else: # user just typed something, we search in message column
            where_sql = self._build_contact_where(account, jid)
            like_sql = '%' + query.replace("'", "''") + '%'
            self.cur.execute('''
                    SELECT contact_name, time, kind, show, message, subject FROM logs
                    WHERE (%s) AND message LIKE '%s'
                    ORDER BY time
                    ''' % (where_sql, like_sql))

        results = self.cur.fetchall()
        return results

    def get_days_with_logs(self, jid, year, month, max_day, account):
        """
        Return the list of days that have logs (not status messages)
        """
        try:
            self.get_jid_id(jid)
        except exceptions.PysqliteOperationalError, e:
            # Error trying to create a new jid_id. This means there is no log
            return []
        days_with_logs = []
        where_sql = self._build_contact_where(account, jid)

        # First select all date of month whith logs we want
        start_of_month = self.get_unix_time_from_date(year, month, 1)
        seconds_in_a_day = 86400 # 60 * 60 * 24
        last_second_of_month = start_of_month + (seconds_in_a_day * max_day) - 1

        # Select times and 'floor' them to time 0:00
        # (by dividing, they are integers)
        # and take only one of the same values (distinct)
        # Now we have timestamps of time 0:00 of every day with logs
        self.cur.execute('''
                SELECT DISTINCT time/(86400)*86400 FROM logs
                WHERE (%s)
                AND time BETWEEN %d AND %d
                AND kind NOT IN (%d, %d)
                ORDER BY time
                ''' % (where_sql, start_of_month, last_second_of_month,
                constants.KIND_STATUS, constants.KIND_GCSTATUS))
        result = self.cur.fetchall()

        # convert timestamps to day of month
        for line in result:
            days_with_logs[0:0]=[time.gmtime(line[0])[2]]

        return days_with_logs

    def get_last_date_that_has_logs(self, jid, account=None, is_room=False):
        """
        Return last time (in seconds since EPOCH) for which we had logs
        (excluding statuses)
        """
        where_sql = ''
        if not is_room:
            where_sql = self._build_contact_where(account, jid)
        else:
            try:
                jid_id = self.get_jid_id(jid, 'ROOM')
            except exceptions.PysqliteOperationalError, e:
                # Error trying to create a new jid_id. This means there is no log
                return None
            where_sql = 'jid_id = %s' % jid_id
        self.cur.execute('''
                SELECT MAX(time) FROM logs
                WHERE (%s)
                AND kind NOT IN (%d, %d)
                ''' % (where_sql, constants.KIND_STATUS, constants.KIND_GCSTATUS))

        results = self.cur.fetchone()
        if results is not None:
            result = results[0]
        else:
            result = None
        return result

    def get_room_last_message_time(self, jid):
        """
        Return FASTLY last time (in seconds since EPOCH) for which we had logs
        for that room from rooms_last_message_time table
        """
        try:
            jid_id = self.get_jid_id(jid, 'ROOM')
        except exceptions.PysqliteOperationalError, e:
            # Error trying to create a new jid_id. This means there is no log
            return None
        where_sql = 'jid_id = %s' % jid_id
        self.cur.execute('''
                SELECT time FROM rooms_last_message_time
                WHERE (%s)
                ''' % (where_sql))

        results = self.cur.fetchone()
        if results is not None:
            result = results[0]
        else:
            result = None
        return result

    def set_room_last_message_time(self, jid, time):
        """
        Set last time (in seconds since EPOCH) for which we had logs for that
        room in rooms_last_message_time table
        """
        jid_id = self.get_jid_id(jid, 'ROOM')
        # jid_id is unique in this table, create or update :
        sql = 'REPLACE INTO rooms_last_message_time VALUES (%d, %d)' % \
                (jid_id, time)
        self.simple_commit(sql)

    def _build_contact_where(self, account, jid):
        """
        Build the where clause for a jid, including metacontacts jid(s) if any
        """
        where_sql = ''
        # will return empty list if jid is not associated with
        # any metacontacts
        family = gajim.contacts.get_metacontacts_family(account, jid)
        if family:
            for user in family:
                try:
                    jid_id = self.get_jid_id(user['jid'])
                except exceptions.PysqliteOperationalError, e:
                    continue
                where_sql += 'jid_id = %s' % jid_id
                if user != family[-1]:
                    where_sql += ' OR '
        else: # if jid was not associated with metacontacts
            jid_id = self.get_jid_id(jid)
            where_sql = 'jid_id = %s' % jid_id
        return where_sql

    def save_transport_type(self, jid, type_):
        """
        Save the type of the transport in DB
        """
        type_id = self.convert_human_transport_type_to_db_api_values(type_)
        if not type_id:
            # unknown type
            return
        self.cur.execute(
                'SELECT type from transports_cache WHERE transport = "%s"' % jid)
        results = self.cur.fetchall()
        if results:
            result = results[0][0]
            if result == type_id:
                return
            sql = 'UPDATE transports_cache SET type = %d WHERE transport = "%s"' %\
                    (type_id, jid)
            self.simple_commit(sql)
            return
        sql = 'INSERT INTO transports_cache VALUES ("%s", %d)' % (jid, type_id)
        self.simple_commit(sql)

    def get_transports_type(self):
        """
        Return all the type of the transports in DB
        """
        self.cur.execute(
                'SELECT * from transports_cache')
        results = self.cur.fetchall()
        if not results:
            return {}
        answer = {}
        for result in results:
            answer[result[0]] = self.convert_api_values_to_human_transport_type(
                    result[1])
        return answer

    # A longer note here:
    # The database contains a blob field. Pysqlite seems to need special care for
    # such fields.
    # When storing, we need to convert string into buffer object (1).
    # When retrieving, we need to convert it back to a string to decompress it.
    # (2)
    # GzipFile needs a file-like object, StringIO emulates file for plain strings
    def iter_caps_data(self):
        """
        Iterate over caps cache data stored in the database

        The iterator values are pairs of (node, ver, ext, identities, features):
        identities == {'category':'foo', 'type':'bar', 'name':'boo'},
        features being a list of feature namespaces.
        """
        # get data from table
        # the data field contains binary object (gzipped data), this is a hack
        # to get that data without trying to convert it to unicode
        try:
            self.cur.execute('SELECT hash_method, hash, data FROM caps_cache;')
        except sqlite.OperationalError:
            # might happen when there's no caps_cache table yet
            # -- there's no data to read anyway then
            return

        # list of corrupted entries that will be removed
        to_be_removed = []
        for hash_method, hash_, data in self.cur:
            # for each row: unpack the data field
            # (format: (category, type, name, category, type, name, ...
            #   ..., 'FEAT', feature1, feature2, ...).join(' '))
            # NOTE: if there's a need to do more gzip, put that to a function
            try:
                data = GzipFile(fileobj=StringIO(str(data))).read().decode(
                        'utf-8').split('\0')
            except IOError:
                # This data is corrupted. It probably contains non-ascii chars
                to_be_removed.append((hash_method, hash_))
                continue
            i = 0
            identities = list()
            features = list()
            while i < (len(data) - 3) and data[i] != 'FEAT':
                category = data[i]
                type_ = data[i + 1]
                lang = data[i + 2]
                name = data[i + 3]
                identities.append({'category': category, 'type': type_,
                        'xml:lang': lang, 'name': name})
                i += 4
            i+=1
            while i < len(data):
                features.append(data[i])
                i += 1

            # yield the row
            yield hash_method, hash_, identities, features
        for hash_method, hash_ in to_be_removed:
            sql = '''DELETE FROM caps_cache WHERE hash_method = "%s" AND
                    hash = "%s"''' % (hash_method, hash_)
            self.simple_commit(sql)

    def add_caps_entry(self, hash_method, hash_, identities, features):
        data = []
        for identity in identities:
            # there is no FEAT category
            if identity['category'] == 'FEAT':
                return
            data.extend((identity.get('category'), identity.get('type', ''),
                    identity.get('xml:lang', ''), identity.get('name', '')))
        data.append('FEAT')
        data.extend(features)
        data = '\0'.join(data)
        # if there's a need to do more gzip, put that to a function
        string = StringIO()
        gzip = GzipFile(fileobj=string, mode='w')
        data = data.encode('utf-8') # the gzip module can't handle unicode objects
        gzip.write(data)
        gzip.close()
        data = string.getvalue()
        self.cur.execute('''
                INSERT INTO caps_cache ( hash_method, hash, data, last_seen )
                VALUES (?, ?, ?, ?);
                ''', (hash_method, hash_, buffer(data), int(time.time())))
        # (1) -- note above
        try:
            self.con.commit()
        except sqlite.OperationalError, e:
            print >> sys.stderr, str(e)

    def update_caps_time(self, method, hash_):
        sql = '''UPDATE caps_cache SET last_seen = %d
                WHERE hash_method = "%s" and hash = "%s"''' % \
                (int(time.time()), method, hash_)
        self.simple_commit(sql)

    def clean_caps_table(self):
        """
        Remove caps which was not seen for 3 months
        """
        sql = '''DELETE FROM caps_cache WHERE last_seen < %d''' % \
                int(time.time() - 3*30*24*3600)
        self.simple_commit(sql)

    def replace_roster(self, account_name, roster_version, roster):
        """
        Replace current roster in DB by a new one

        accout_name is the name of the account to change.
        roster_version is the version of the new roster.
        roster is the new version.
        """
        # First we must reset roster_version value to ensure that the server
        # sends back all the roster at the next connexion if the replacement
        # didn't work properly.
        gajim.config.set_per('accounts', account_name, 'roster_version', '')

        account_jid = gajim.get_jid_from_account(account_name)
        account_jid_id = self.get_jid_id(account_jid)

        # Delete old roster
        self.remove_roster(account_jid)

        # Fill roster tables with the new roster
        for jid in roster:
            self.add_or_update_contact(account_jid, jid, roster[jid]['name'],
                    roster[jid]['subscription'], roster[jid]['ask'],
                    roster[jid]['groups'], commit=False)
        self.con.commit()

        # At this point, we are sure the replacement works properly so we can
        # set the new roster_version value.
        gajim.config.set_per('accounts', account_name, 'roster_version',
            roster_version)

    def del_contact(self, account_jid, jid):
        """
        Remove jid from account_jid roster
        """
        try:
            account_jid_id = self.get_jid_id(account_jid)
            jid_id = self.get_jid_id(jid)
        except exceptions.PysqliteOperationalError, e:
            raise exceptions.PysqliteOperationalError(str(e))
        self.cur.execute(
                'DELETE FROM roster_group WHERE account_jid_id=? AND jid_id=?',
                (account_jid_id, jid_id))
        self.cur.execute(
                'DELETE FROM roster_entry WHERE account_jid_id=? AND jid_id=?',
                (account_jid_id, jid_id))
        self.con.commit()

    def add_or_update_contact(self, account_jid, jid, name, sub, ask, groups,
    commit=True):
        """
        Add or update a contact from account_jid roster
        """
        if sub == 'remove':
            self.del_contact(account_jid, jid)
            return

        try:
            account_jid_id = self.get_jid_id(account_jid)
            jid_id = self.get_jid_id(jid)
        except exceptions.PysqliteOperationalError, e:
            raise exceptions.PysqliteOperationalError(str(e))

        # Update groups information
        # First we delete all previous groups information
        self.cur.execute(
                'DELETE FROM roster_group WHERE account_jid_id=? AND jid_id=?',
                (account_jid_id, jid_id))
        # Then we add all new groups information
        for group in groups:
            self.cur.execute('INSERT INTO roster_group VALUES(?, ?, ?)',
                    (account_jid_id, jid_id, group))

        if name is None:
            name = ''

        self.cur.execute('REPLACE INTO roster_entry VALUES(?, ?, ?, ?, ?)',
                (account_jid_id, jid_id, name,
                self.convert_human_subscription_values_to_db_api_values(sub),
                bool(ask)))
        if commit:
            self.con.commit()

    def get_roster(self, account_jid):
        """
        Return the accound_jid roster in NonBlockingRoster format
        """
        data = {}
        account_jid_id = self.get_jid_id(account_jid)

        # First we fill data with roster_entry informations
        self.cur.execute('''
                SELECT j.jid, re.jid_id, re.name, re.subscription, re.ask
                FROM roster_entry re, jids j
                WHERE re.account_jid_id=? AND j.jid_id=re.jid_id''', (account_jid_id,))
        for jid, jid_id, name, subscription, ask in self.cur:
            data[jid] = {}
            if name:
                data[jid]['name'] = name
            else:
                data[jid]['name'] = None
            data[jid]['subscription'] = \
                    self.convert_db_api_values_to_human_subscription_values(
                    subscription)
            data[jid]['groups'] = []
            data[jid]['resources'] = {}
            if ask:
                data[jid]['ask'] = 'subscribe'
            else:
                data[jid]['ask'] = None
            data[jid]['id'] = jid_id

        # Then we add group for roster entries
        for jid in data:
            self.cur.execute('''
                    SELECT group_name FROM roster_group
                    WHERE account_jid_id=? AND jid_id=?''',
                    (account_jid_id, data[jid]['id']))
            for (group_name,) in self.cur:
                data[jid]['groups'].append(group_name)
            del data[jid]['id']

        return data

    def remove_roster(self, account_jid):
        """
        Remove all entry from account_jid roster
        """
        account_jid_id = self.get_jid_id(account_jid)

        self.cur.execute('DELETE FROM roster_entry WHERE account_jid_id=?',
                (account_jid_id,))
        self.cur.execute('DELETE FROM roster_group WHERE account_jid_id=?',
                (account_jid_id,))
        self.con.commit()

    def save_if_not_exists(self, with_, direction, tim, msg='', nick=None):
        if tim:
            time_col = int(float(time.mktime(tim)))
        else:
            time_col = int(float(time.time()))
        if msg:
            if self.jid_is_from_pm(with_) or nick:
                # It's a groupchat message
                if nick:
                    # It's a message from a groupchat occupent
                    type_ = 'gc_msg'
                    with_ = with_ + '/' + nick
                else:
                    # It's a server message message, we don't log them
                    return
            else:
                if direction == 'from':
                    type_ = 'chat_msg_recv'
                elif direction == 'to':
                    type_ = 'chat_msg_sent'
        jid_id = self.get_jid_id(with_)
        where_sql = 'jid_id = %s AND message=?' % jid_id
        if type_ == 'gc_msg':
            # We cannot differentiate gc message and pm messages, so look in
            # both logs
            with_2 = gajim.get_jid_without_resource(with_)
            if with_ != with_2:
                jid_id2 = self.get_jid_id(with_2)
                where_sql = 'jid_id in (%s, %s) AND message=?' % (jid_id,
                    jid_id2)
        start_time = time_col - 300 # 5 minutes arrount given time
        end_time = time_col + 300 # 5 minutes arrount given time
        self.cur.execute('''
            SELECT log_line_id FROM logs
            WHERE (%s)
            AND time BETWEEN %d AND %d
            ORDER BY time
            ''' % (where_sql, start_time, end_time), (msg,))
        results = self.cur.fetchall()
        if results:
            log.debug('Log already in DB, ignoring it')
            return
        log.debug('New log received from server archives, storing it')
        self.write(type_, with_, message=msg, tim=tim)