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

# SAT: a jabber client
# Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014 Jérôme Poisson (goffi@goffi.org)

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.

# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from sat.core.i18n import _
from sat.core import exceptions
from sat.core.log import getLogger
log = getLogger(__name__)
from twisted.enterprise import adbapi
from twisted.internet import defer
from collections import OrderedDict
from time import time
import re
import os.path
import cPickle as pickle
import hashlib

CURRENT_DB_VERSION = 1

# XXX: DATABASE schemas are used in the following way:
#      - 'current' key is for the actual database schema, for a new base
#      - x(int) is for update needed between x-1 and x. All number are needed between y and z to do an update
#        e.g.: if CURRENT_DB_VERSION is 6, 'current' is the actuel DB, and to update from version 3, numbers 4, 5 and 6 are needed
#      a 'current' data dict can contains the keys:
#      - 'CREATE': it contains an Ordered dict with table to create as keys, and a len 2 tuple as value, where value[0] are the columns definitions and value[1] are the table constraints
#      - 'INSERT': it contains an Ordered dict with table where values have to be inserted, and many tuples containing values to insert in the order of the rows (#TODO: manage named columns)
#      an update data dict (the ones with a number) can contains the keys 'create', 'delete', 'cols create', 'cols delete', 'cols modify' or 'insert'. See Updater.generateUpdateData for more infos. This metho can be used to autogenerate update_data, to ease the work of the developers.

DATABASE_SCHEMAS = {
        "current": {'CREATE': OrderedDict((
                              ('profiles',        (("id INTEGER PRIMARY KEY ASC", "name TEXT"),
                                                   ("UNIQUE (name)",))),
                              ('message_types',   (("type TEXT PRIMARY KEY",),
                                                   tuple())),
                              ('history',         (("id INTEGER PRIMARY KEY ASC", "profile_id INTEGER", "source TEXT", "dest TEXT", "source_res TEXT", "dest_res TEXT", "timestamp DATETIME", "message TEXT", "type TEXT", "extra BLOB"),
                                                   ("FOREIGN KEY(profile_id) REFERENCES profiles(id) ON DELETE CASCADE", "FOREIGN KEY(type) REFERENCES message_types(type)"))),
                              ('param_gen',       (("category TEXT", "name TEXT", "value TEXT"),
                                                   ("PRIMARY KEY (category,name)",))),
                              ('param_ind',       (("category TEXT", "name TEXT", "profile_id INTEGER", "value TEXT"),
                                                   ("PRIMARY KEY (category,name,profile_id)", "FOREIGN KEY(profile_id) REFERENCES profiles(id) ON DELETE CASCADE"))),
                              ('private_gen',     (("namespace TEXT", "key TEXT", "value TEXT"),
                                                   ("PRIMARY KEY (namespace, key)",))),
                              ('private_ind',     (("namespace TEXT", "key TEXT", "profile_id INTEGER", "value TEXT"),
                                                   ("PRIMARY KEY (namespace, key, profile_id)", "FOREIGN KEY(profile_id) REFERENCES profiles(id) ON DELETE CASCADE"))),
                              ('private_gen_bin', (("namespace TEXT", "key TEXT", "value BLOB"),
                                                   ("PRIMARY KEY (namespace, key)",))),

                              ('private_ind_bin', (("namespace TEXT", "key TEXT", "profile_id INTEGER", "value BLOB"),
                                                   ("PRIMARY KEY (namespace, key, profile_id)", "FOREIGN KEY(profile_id) REFERENCES profiles(id) ON DELETE CASCADE")))
                              )),
                    'INSERT': OrderedDict((
                              ('message_types', (("'chat'",), ("'error'",), ("'groupchat'",), ("'headline'",), ("'normal'",))),
                              )),
                    },
        1:         {'cols create': {'history': ('extra BLOB',)}
                   },
        }


class SqliteStorage(object):
    """This class manage storage with Sqlite database"""

    def __init__(self, db_filename, sat_version):
        """Connect to the given database
        @param db_filename: full path to the Sqlite database"""
        self.initialized = defer.Deferred()  # triggered when memory is fully initialised and ready
        self.profiles = {}  # we keep cache for the profiles (key: profile name, value: profile id)

        log.info(_("Connecting database"))
        new_base = not os.path.exists(db_filename)  # do we have to create the database ?
        if new_base:  # the dir may not exist if it's not the XDG recommended one
            dir_ = os.path.dirname(db_filename)
            if not os.path.exists(dir_):
                os.makedirs(dir_, 0700)
        self.dbpool = adbapi.ConnectionPool("sqlite3", db_filename, check_same_thread=False)

        # init_defer is the initialisation deferred, initialisation is ok when all its callbacks have been done
        # XXX: foreign_keys activation doesn't seem to work, probably because of the multi-threading
        # All the requests that need to use this feature should be run with runInteraction instead,
        # so you can set the PRAGMA as it is done in self.deleteProfile
        init_defer = self.dbpool.runOperation("PRAGMA foreign_keys = ON").addErrback(lambda x: log.error(_("Can't activate foreign keys")))

        def getNewBaseSql():
            log.info(_("The database is new, creating the tables"))
            database_creation = ["PRAGMA user_version=%d" % CURRENT_DB_VERSION]
            database_creation.extend(Updater.createData2Raw(DATABASE_SCHEMAS['current']['CREATE']))
            database_creation.extend(Updater.insertData2Raw(DATABASE_SCHEMAS['current']['INSERT']))
            return database_creation

        def getUpdateSql():
            updater = Updater(self.dbpool, sat_version)
            return updater.checkUpdates()

        def commitStatements(statements):

            if statements is None:
                return defer.succeed(None)
            log.debug("===== COMMITING STATEMENTS =====\n%s\n============\n\n" % '\n'.join(statements))
            d = self.dbpool.runInteraction(self._updateDb, tuple(statements))
            return d

        init_defer.addCallback(lambda ignore: getNewBaseSql() if new_base else getUpdateSql())
        init_defer.addCallback(commitStatements)

        def fillProfileCache(ignore):
            d = self.dbpool.runQuery("SELECT name,id FROM profiles").addCallback(self._profilesCache)
            d.chainDeferred(self.initialized)

        init_defer.addCallback(fillProfileCache)

    def _updateDb(self, interaction, statements):
        for statement in statements:
            interaction.execute(statement)


    #Profiles
    def _profilesCache(self, profiles_result):
        """Fill the profiles cache
        @param profiles_result: result of the sql profiles query"""
        for profile in profiles_result:
            name, id_ = profile
            self.profiles[name] = id_

    def getProfilesList(self):
        """"Return list of all registered profiles"""
        return self.profiles.keys()

    def hasProfile(self, profile_name):
        """return True if profile_name exists
        @param profile_name: name of the profile to check"""
        return profile_name in self.profiles

    def createProfile(self, name):
        """Create a new profile
        @param name: name of the profile
        @return: deferred triggered once profile is actually created"""

        def getProfileId(ignore):
            return self.dbpool.runQuery("SELECT (id) FROM profiles WHERE name = ?", (name, ))

        def profile_created(profile_id):
            _id = profile_id[0][0]
            self.profiles[name] = _id  # we synchronise the cache

        d = self.dbpool.runQuery("INSERT INTO profiles(name) VALUES (?)", (name, ))
        d.addCallback(getProfileId)
        d.addCallback(profile_created)
        return d

    def deleteProfile(self, name):
        """Delete profile
        @param name: name of the profile
        @return: deferred triggered once profile is actually deleted"""
        def deletionError(failure):
            log.error(_("Can't delete profile [%s]") % name)
            return failure

        def delete(txn):
            del self.profiles[name]
            txn.execute("PRAGMA foreign_keys = ON")
            txn.execute("DELETE FROM profiles WHERE name = ?", (name,))
            return None

        d = self.dbpool.runInteraction(delete)
        d.addCallback(lambda ignore: log.info(_("Profile [%s] deleted") % name))
        d.addErrback(deletionError)
        return d

    #Params
    def loadGenParams(self, params_gen):
        """Load general parameters
        @param params_gen: dictionary to fill
        @return: deferred"""

        def fillParams(result):
            for param in result:
                category, name, value = param
                params_gen[(category, name)] = value
        log.debug(_("loading general parameters from database"))
        return self.dbpool.runQuery("SELECT category,name,value FROM param_gen").addCallback(fillParams)

    def loadIndParams(self, params_ind, profile):
        """Load individual parameters
        @param params_ind: dictionary to fill
        @param profile: a profile which *must* exist
        @return: deferred"""

        def fillParams(result):
            for param in result:
                category, name, value = param
                params_ind[(category, name)] = value
        log.debug(_("loading individual parameters from database"))
        d = self.dbpool.runQuery("SELECT category,name,value FROM param_ind WHERE profile_id=?", (self.profiles[profile], ))
        d.addCallback(fillParams)
        return d

    def getIndParam(self, category, name, profile):
        """Ask database for the value of one specific individual parameter
        @param category: category of the parameter
        @param name: name of the parameter
        @param profile: %(doc_profile)s
        @return: deferred"""
        d = self.dbpool.runQuery("SELECT value FROM param_ind WHERE category=? AND name=? AND profile_id=?", (category, name, self.profiles[profile]))
        d.addCallback(self.__getFirstResult)
        return d

    def setGenParam(self, category, name, value):
        """Save the general parameters in database
        @param category: category of the parameter
        @param name: name of the parameter
        @param value: value to set
        @return: deferred"""
        d = self.dbpool.runQuery("REPLACE INTO param_gen(category,name,value) VALUES (?,?,?)", (category, name, value))
        d.addErrback(lambda ignore: log.error(_("Can't set general parameter (%(category)s/%(name)s) in database" % {"category": category, "name": name})))
        return d

    def setIndParam(self, category, name, value, profile):
        """Save the individual parameters in database
        @param category: category of the parameter
        @param name: name of the parameter
        @param value: value to set
        @param profile: a profile which *must* exist
        @return: deferred"""
        d = self.dbpool.runQuery("REPLACE INTO param_ind(category,name,profile_id,value) VALUES (?,?,?,?)", (category, name, self.profiles[profile], value))
        d.addErrback(lambda ignore: log.error(_("Can't set individual parameter (%(category)s/%(name)s) for [%(profile)s] in database" % {"category": category, "name": name, "profile": profile})))
        return d

    #History
    def addToHistory(self, from_jid, to_jid, message, _type='chat', extra=None, timestamp=None, profile=None):
        """Store a new message in history
        @param from_jid: full source JID
        @param to_jid: full dest JID
        @param message: message
        @param _type: message type (see RFC 6121 §5.2.2)
        @param extra: dictionary (keys and values are unicode) of extra message data
        @param timestamp: timestamp in seconds since epoch, or None to use current time
        """
        assert(profile)
        if extra is None:
            extra = {}
        extra_ = pickle.dumps({k: v.encode('utf-8') for k, v in extra.items()}, 0).decode('utf-8')
        d = self.dbpool.runQuery("INSERT INTO history(source, source_res, dest, dest_res, timestamp, message, type, extra, profile_id) VALUES (?,?,?,?,?,?,?,?,?)",
                                 (from_jid.userhost(), from_jid.resource, to_jid.userhost(), to_jid.resource, timestamp or time(),
                                  message, _type, extra_, self.profiles[profile]))
        d.addErrback(lambda ignore: log.error(_("Can't save following message in history: from [%(from_jid)s] to [%(to_jid)s] ==> [%(message)s]" %
                                          {"from_jid": from_jid.full(), "to_jid": to_jid.full(), "message": message})))
        return d

    def getHistory(self, from_jid, to_jid, limit=0, between=True, profile=None):
        """Store a new message in history
        @param from_jid: source JID (full, or bare for catchall
        @param to_jid: dest JID (full, or bare for catchall
        @param size: maximum number of messages to get, or 0 for unlimited
        """
        assert(profile)

        def sqliteToList(query_result):
            query_result.reverse()
            result = []
            for row in query_result:
                timestamp, source, source_res, dest, dest_res, message, type_, extra_raw = row
                try:
                    extra = pickle.loads(str(extra_raw or ""))
                except EOFError:
                    extra = {}
                result.append((timestamp, "%s/%s" % (source, source_res) if source_res else source,
                                          "%s/%s" % (dest, dest_res) if dest_res else dest,
                                          message, type_, extra))
            return result

        query_parts = ["SELECT timestamp, source, source_res, dest, dest_res, message, type, extra FROM history WHERE profile_id=? AND"]
        values = [self.profiles[profile]]

        def test_jid(type_, _jid):
            values.append(_jid.userhost())
            if _jid.resource:
                values.append(_jid.resource)
                return '(%s=? AND %s_res=?)' % (type_, type_)
            return '%s=?' % (type_, )

        if between:
            query_parts.append("((%s AND %s) OR (%s AND %s))" % (test_jid('source', from_jid),
                                                             test_jid('dest', to_jid),
                                                             test_jid('source', to_jid),
                                                             test_jid('dest', from_jid)))
        else:
            query_parts.append("%s AND %s" % (test_jid('source', from_jid),
                                              test_jid('dest', to_jid)))

        query_parts.append("ORDER BY timestamp DESC")

        if limit:
            query_parts.append("LIMIT ?")
            values.append(limit)

        d = self.dbpool.runQuery(" ".join(query_parts), values)
        return d.addCallback(sqliteToList)

    #Private values
    def loadGenPrivates(self, private_gen, namespace):
        """Load general private values
        @param private_gen: dictionary to fill
        @param namespace: namespace of the values
        @return: deferred"""

        def fillPrivates(result):
            for private in result:
                key, value = private
                private_gen[key] = value
        log.debug(_("loading general private values [namespace: %s] from database") % (namespace, ))
        d = self.dbpool.runQuery("SELECT key,value FROM private_gen WHERE namespace=?", (namespace, )).addCallback(fillPrivates)
        return d.addErrback(lambda x: log.debug(_("No data present in database for namespace %s") % namespace))

    def loadIndPrivates(self, private_ind, namespace, profile):
        """Load individual private values
        @param privates_ind: dictionary to fill
        @param namespace: namespace of the values
        @param profile: a profile which *must* exist
        @return: deferred"""

        def fillPrivates(result):
            for private in result:
                key, value = private
                private_ind[key] = value
        log.debug(_("loading individual private values [namespace: %s] from database") % (namespace, ))
        d = self.dbpool.runQuery("SELECT key,value FROM private_ind WHERE namespace=? AND profile_id=?", (namespace, self.profiles[profile]))
        d.addCallback(fillPrivates)
        return d.addErrback(lambda x: log.debug(_("No data present in database for namespace %s") % namespace))

    def setGenPrivate(self, namespace, key, value):
        """Save the general private value in database
        @param category: category of the privateeter
        @param key: key of the private value
        @param value: value to set
        @return: deferred"""
        d = self.dbpool.runQuery("REPLACE INTO private_gen(namespace,key,value) VALUES (?,?,?)", (namespace, key, value))
        d.addErrback(lambda ignore: log.error(_("Can't set general private value (%(key)s) [namespace:%(namespace)s] in database" %
                     {"namespace": namespace, "key": key})))
        return d

    def setIndPrivate(self, namespace, key, value, profile):
        """Save the individual private value in database
        @param namespace: namespace of the value
        @param key: key of the private value
        @param value: value to set
        @param profile: a profile which *must* exist
        @return: deferred"""
        d = self.dbpool.runQuery("REPLACE INTO private_ind(namespace,key,profile_id,value) VALUES (?,?,?,?)", (namespace, key, self.profiles[profile], value))
        d.addErrback(lambda ignore: log.error(_("Can't set individual private value (%(key)s) [namespace: %(namespace)s] for [%(profile)s] in database" %
                     {"namespace": namespace, "key": key, "profile": profile})))
        return d

    def delGenPrivate(self, namespace, key):
        """Delete the general private value from database
        @param category: category of the privateeter
        @param key: key of the private value
        @return: deferred"""
        d = self.dbpool.runQuery("DELETE FROM private_gen WHERE namespace=? AND key=?", (namespace, key))
        d.addErrback(lambda ignore: log.error(_("Can't delete general private value (%(key)s) [namespace:%(namespace)s] in database" %
                     {"namespace": namespace, "key": key})))
        return d

    def delIndPrivate(self, namespace, key, profile):
        """Delete the individual private value from database
        @param namespace: namespace of the value
        @param key: key of the private value
        @param profile: a profile which *must* exist
        @return: deferred"""
        d = self.dbpool.runQuery("DELETE FROM private_ind WHERE namespace=? AND key=? AND profile=?)", (namespace, key, self.profiles[profile]))
        d.addErrback(lambda ignore: log.error(_("Can't delete individual private value (%(key)s) [namespace: %(namespace)s] for [%(profile)s] in database" %
                     {"namespace": namespace, "key": key, "profile": profile})))
        return d

    def loadGenPrivatesBinary(self, private_gen, namespace):
        """Load general private binary values
        @param private_gen: dictionary to fill
        @param namespace: namespace of the values
        @return: deferred"""

        def fillPrivates(result):
            for private in result:
                key, value = private
                private_gen[key] = pickle.loads(str(value))
        log.debug(_("loading general private binary values [namespace: %s] from database") % (namespace, ))
        d = self.dbpool.runQuery("SELECT key,value FROM private_gen_bin WHERE namespace=?", (namespace, )).addCallback(fillPrivates)
        return d.addErrback(lambda x: log.debug(_("No binary data present in database for namespace %s") % namespace))

    def loadIndPrivatesBinary(self, private_ind, namespace, profile):
        """Load individual private binary values
        @param privates_ind: dictionary to fill
        @param namespace: namespace of the values
        @param profile: a profile which *must* exist
        @return: deferred"""

        def fillPrivates(result):
            for private in result:
                key, value = private
                private_ind[key] = pickle.loads(str(value))
        log.debug(_("loading individual private binary values [namespace: %s] from database") % (namespace, ))
        d = self.dbpool.runQuery("SELECT key,value FROM private_ind_bin WHERE namespace=? AND profile_id=?", (namespace, self.profiles[profile]))
        d.addCallback(fillPrivates)
        return d.addErrback(lambda x: log.debug(_("No binary data present in database for namespace %s") % namespace))

    def setGenPrivateBinary(self, namespace, key, value):
        """Save the general private binary value in database
        @param category: category of the privateeter
        @param key: key of the private value
        @param value: value to set
        @return: deferred"""
        d = self.dbpool.runQuery("REPLACE INTO private_gen_bin(namespace,key,value) VALUES (?,?,?)", (namespace, key, pickle.dumps(value, 0)))
        d.addErrback(lambda ignore: log.error(_("Can't set general private binary value (%(key)s) [namespace:%(namespace)s] in database" %
                     {"namespace": namespace, "key": key})))
        return d

    def setIndPrivateBinary(self, namespace, key, value, profile):
        """Save the individual private binary value in database
        @param namespace: namespace of the value
        @param key: key of the private value
        @param value: value to set
        @param profile: a profile which *must* exist
        @return: deferred"""
        d = self.dbpool.runQuery("REPLACE INTO private_ind_bin(namespace,key,profile_id,value) VALUES (?,?,?,?)", (namespace, key, self.profiles[profile], pickle.dumps(value, 0)))
        d.addErrback(lambda ignore: log.error(_("Can't set individual binary private value (%(key)s) [namespace: %(namespace)s] for [%(profile)s] in database" %
                     {"namespace": namespace, "key": key, "profile": profile})))
        return d

    def delGenPrivateBinary(self, namespace, key):
        """Delete the general private binary value from database
        @param category: category of the privateeter
        @param key: key of the private value
        @return: deferred"""
        d = self.dbpool.runQuery("DELETE FROM private_gen_bin WHERE namespace=? AND key=?", (namespace, key))
        d.addErrback(lambda ignore: log.error(_("Can't delete general private binary value (%(key)s) [namespace:%(namespace)s] in database" %
                     {"namespace": namespace, "key": key})))
        return d

    def delIndPrivateBinary(self, namespace, key, profile):
        """Delete the individual private binary value from database
        @param namespace: namespace of the value
        @param key: key of the private value
        @param profile: a profile which *must* exist
        @return: deferred"""
        d = self.dbpool.runQuery("DELETE FROM private_ind_bin WHERE namespace=? AND key=? AND profile=?)", (namespace, key, self.profiles[profile]))
        d.addErrback(lambda ignore: log.error(_("Can't delete individual private binary value (%(key)s) [namespace: %(namespace)s] for [%(profile)s] in database" %
                     {"namespace": namespace, "key": key, "profile": profile})))
        return d
    ##Helper methods##

    def __getFirstResult(self, result):
        """Return the first result of a database query
        Useful when we are looking for one specific value"""
        return None if not result else result[0][0]


class Updater(object):
    stmnt_regex = re.compile(r"(?:[\w ]+(?:\([\w, ]+\))?)+")
    clean_regex = re.compile(r"^ +|(?<= ) +|(?<=,) +| +$")
    CREATE_SQL = "CREATE TABLE %s (%s)"
    INSERT_SQL = "INSERT INTO %s VALUES (%s)"
    DROP_SQL = "DROP TABLE %s"
    ALTER_SQL = "ALTER TABLE %s ADD COLUMN %s"
    RENAME_TABLE_SQL = "ALTER TABLE %s RENAME TO %s"

    CONSTRAINTS = ('PRIMARY', 'UNIQUE', 'CHECK', 'FOREIGN')
    TMP_TABLE = "tmp_sat_update"

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

    def getLocalVersion(self):
        """ Get local database version
        @return: version (int)

        """
        return self.dbpool.runQuery("PRAGMA user_version").addCallback(lambda ret: int(ret[0][0]))

    def _setLocalVersion(self, version):
        """ Set local database version
        @param version: version (int)
        @return: deferred

        """
        return self.dbpool.runOperation("PRAGMA user_version=%d" % version)

    def getLocalSchema(self):
        """ return raw local schema
        @return: list of strings with CREATE sql statements for local database

        """
        d = self.dbpool.runQuery("select sql from sqlite_master where type = 'table'")
        d.addCallback(lambda result: [row[0] for row in result])
        return d

    @defer.inlineCallbacks
    def checkUpdates(self):
        """ Check is database schema update is needed, according to DATABASE_SCHEMAS
        @return: deferred which fire a list of SQL update statements, or None if no update is needed

        """
        local_version = yield self.getLocalVersion()
        raw_local_sch = yield self.getLocalSchema()
        local_sch = self.rawStatements2data(raw_local_sch)
        current_sch = DATABASE_SCHEMAS['current']['CREATE']
        local_hash = self.statementHash(local_sch)
        current_hash = self.statementHash(current_sch)

        if local_hash == current_hash:
            if local_version != CURRENT_DB_VERSION:
                log.warning(_("Your local schema is up-to-date, but database versions mismatch, fixing it..."))
                yield self._setLocalVersion(CURRENT_DB_VERSION)
        else:
            # an update is needed

            if local_version == CURRENT_DB_VERSION:
                # Database mismatch and we have the latest version
                if self._sat_version.endswith('D'):
                    # we are in a development version
                    update_data = self.generateUpdateData(local_sch, current_sch, False)
                    log.warning(_("There is a schema mismatch, but as we are on a dev version, database will be updated"))
                    update_raw = self.update2raw(update_data, True)
                    defer.returnValue(update_raw)
                else:
                    log.error(_(u"schema version is up-to-date, but local schema differ from expected current schema"))
                    update_data = self.generateUpdateData(local_sch, current_sch, True)
                    log.warning(_(u"Here are the commands that should fix the situation, use at your own risk (do a backup before modifying database), you can go to SàT's MUC room at sat@chat.jabberfr.org for help\n### SQL###\n%s\n### END SQL ###\n") % u'\n'.join(("%s;" % statement for statement in self.update2raw(update_data))))
                    raise exceptions.DatabaseError("Database mismatch")
            else:
                # Database is not up-to-date, we'll do the update
                log.info(_("Database schema has changed, local database will be updated"))
                update_raw = []
                for version in xrange(local_version+1, CURRENT_DB_VERSION+1):
                    try:
                        update_data = DATABASE_SCHEMAS[version]
                    except KeyError:
                        raise exceptions.InternalError("Missing update definition (version %d)" % version)
                    update_raw.extend(self.update2raw(update_data))
                update_raw.append("PRAGMA user_version=%d" % CURRENT_DB_VERSION)
                defer.returnValue(update_raw)

    @staticmethod
    def createData2Raw(data):
        """ Generate SQL statements from statements data
        @param data: dictionary with table as key, and statements data in tuples as value
        @return: list of strings with raw statements

        """
        ret = []
        for table in data:
            defs, constraints = data[table]
            assert isinstance(defs, tuple)
            assert isinstance(constraints, tuple)
            ret.append(Updater.CREATE_SQL % (table, ', '.join(defs + constraints)))
        return ret

    @staticmethod
    def insertData2Raw(data):
        """ Generate SQL statements from statements data
        @param data: dictionary with table as key, and statements data in tuples as value
        @return: list of strings with raw statements

        """
        ret = []
        for table in data:
            values_tuple = data[table]
            assert isinstance(values_tuple, tuple)
            for values in values_tuple:
                assert isinstance(values, tuple)
                ret.append(Updater.INSERT_SQL % (table, ', '.join(values)))
        return ret

    def statementHash(self, data):
        """ Generate hash of template data
        useful to compare schemas

        @param data: dictionary of "CREATE" statement, with tables names as key,
                     and tuples of (col_defs, constraints) as values
        @return: hash as string
        """
        hash_ = hashlib.sha1()
        tables = data.keys()
        tables.sort()

        def stmnts2str(stmts):
            return ','.join([self.clean_regex.sub('',stmt) for stmt in sorted(stmts)])

        for table in tables:
            col_defs, col_constr = data[table]
            hash_.update("%s:%s:%s" % (table, stmnts2str(col_defs), stmnts2str(col_constr)))
        return hash_.digest()

    def rawStatements2data(self, raw_statements):
        """ separate "CREATE" statements into dictionary/tuples data
        @param raw_statements: list of CREATE statements as strings
        @return: dictionary with table names as key, and a (col_defs, constraints) tuple

        """
        schema_dict = {}
        for create_statement in raw_statements:
            if not create_statement.startswith("CREATE TABLE "):
                log.warning("Unexpected statement, ignoring it")
                continue
            _create_statement = create_statement[13:]
            table, raw_col_stats = _create_statement.split(' ',1)
            if raw_col_stats[0] != '(' or raw_col_stats[-1] != ')':
                log.warning("Unexpected statement structure, ignoring it")
                continue
            col_stats = [stmt.strip() for stmt in self.stmnt_regex.findall(raw_col_stats[1:-1])]
            col_defs = []
            constraints = []
            for col_stat in col_stats:
                name = col_stat.split(' ',1)[0]
                if name in self.CONSTRAINTS:
                    constraints.append(col_stat)
                else:
                    col_defs.append(col_stat)
            schema_dict[table] = (tuple(col_defs), tuple(constraints))
        return schema_dict

    def generateUpdateData(self, old_data, new_data, modify=False):
        """ Generate data for automatic update between two schema data
        @param old_data: data of the former schema (which must be updated)
        @param new_data: data of the current schema
        @param modify: if True, always use "cols modify" table, else try to ALTER tables
        @return: update data, a dictionary with:
                 - 'create': dictionary of tables to create
                 - 'delete': tuple of tables to delete
                 - 'cols create': dictionary of columns to create (table as key, tuple of columns to create as value)
                 - 'cols delete': dictionary of columns to delete (table as key, tuple of columns to delete as value)
                 - 'cols modify': dictionary of columns to modify (table as key, tuple of old columns to transfert as value). With this table, a new table will be created, and content from the old table will be transfered to it, only cols specified in the tuple will be transfered.

        """

        create_tables_data = {}
        create_cols_data = {}
        modify_cols_data = {}
        delete_cols_data = {}
        old_tables = set(old_data.keys())
        new_tables = set(new_data.keys())

        def getChanges(set_olds, set_news):
            to_create = set_news.difference(set_olds)
            to_delete = set_olds.difference(set_news)
            to_check = set_news.intersection(set_olds)
            return tuple(to_create), tuple(to_delete), tuple(to_check)

        tables_to_create, tables_to_delete, tables_to_check = getChanges(old_tables, new_tables)

        for table in tables_to_create:
            create_tables_data[table] = new_data[table]

        for table in tables_to_check:
            old_col_defs, old_constraints = old_data[table]
            new_col_defs, new_constraints = new_data[table]
            for obj in old_col_defs, old_constraints, new_col_defs, new_constraints:
                if not isinstance(obj, tuple):
                    raise exceptions.InternalError("Columns definitions must be tuples")
            defs_create, defs_delete, ignore = getChanges(set(old_col_defs), set(new_col_defs))
            constraints_create, constraints_delete, ignore = getChanges(set(old_constraints), set(new_constraints))
            created_col_names = set([name.split(' ',1)[0] for name in defs_create])
            deleted_col_names = set([name.split(' ',1)[0] for name in defs_delete])
            if (created_col_names.intersection(deleted_col_names or constraints_create or constraints_delete) or
                (modify and (defs_create or constraints_create or defs_delete or constraints_delete))):
                # we have modified columns, we need to transfer table
                # we determinate which columns are in both schema so we can transfer them
                old_names = set([name.split(' ',1)[0] for name in old_col_defs])
                new_names = set([name.split(' ',1)[0] for name in new_col_defs])
                modify_cols_data[table] = tuple(old_names.intersection(new_names));
            else:
                if defs_create:
                    create_cols_data[table] = (defs_create)
                if defs_delete or constraints_delete:
                    delete_cols_data[table] = (defs_delete)

        return {'create': create_tables_data,
                'delete': tables_to_delete,
                'cols create': create_cols_data,
                'cols delete': delete_cols_data,
                'cols modify': modify_cols_data
                }

    def update2raw(self, update, dev_version=False):
        """ Transform update data to raw SQLite statements
        @param upadte: update data as returned by generateUpdateData
        @param dev_version: if True, update will be done in dev mode: no deletion will be done, instead a message will be shown. This prevent accidental lost of data while working on the code/database.
        @return: list of string with SQL statements needed to update the base

        """
        ret = self.createData2Raw(update.get('create', {}))
        drop = []
        for table in update.get('delete', tuple()):
            drop.append(self.DROP_SQL % table)
        if dev_version:
            if drop:
                log.info("Dev version, SQL NOT EXECUTED:\n--\n%s\n--\n" % "\n".join(drop))
        else:
            ret.extend(drop)

        cols_create = update.get('cols create', {})
        for table in cols_create:
            for col_def in cols_create[table]:
                ret.append(self.ALTER_SQL % (table, col_def))

        cols_delete = update.get('cols delete', {})
        for table in cols_delete:
            log.info("Following columns in table [%s] are not needed anymore, but are kept for dev version: %s" % (table, ", ".join(cols_delete[table])))

        cols_modify = update.get('cols modify', {})
        for table in cols_modify:
            ret.append(self.RENAME_TABLE_SQL % (table, self.TMP_TABLE))
            main, extra = DATABASE_SCHEMAS['current']['CREATE'][table]
            ret.append(self.CREATE_SQL % (table, ', '.join(main + extra)))
            common_cols = ', '.join(cols_modify[table])
            ret.append("INSERT INTO %s (%s) SELECT %s FROM %s" % (table, common_cols, common_cols, self.TMP_TABLE))
            ret.append(self.DROP_SQL % self.TMP_TABLE)

        insert = update.get('insert', {})
        ret.extend(self.insertData2Raw(insert))

        return ret