# coding: utf-8

# copyright 2015-2016 LOGILAB S.A. (Paris, FRANCE), all rights reserved.

# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr

#

# This file is part of CubicWeb.

#

# CubicWeb is free software: you can redistribute it and/or modify it under the

# terms of the GNU Lesser General Public License as published by the Free

# Software Foundation, either version 2.1 of the License, or (at your option)

# any later version.

#

# CubicWeb 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 Lesser General Public License for more

# details.

#

# You should have received a copy of the GNU Lesser General Public License along

# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.

import logging

from copy import copy

from collections import defaultdict

from io import StringIO

from itertools import chain

from base64 import b64encode

from six.moves import range

from yams.constraints import SizeConstraint

from cubicweb.schema import PURE_VIRTUAL_RTYPES

from cubicweb.server.schema2sql import rschema_has_table

from cubicweb.dataimport import stores, pgstore

class MassiveObjectStore(stores.RQLObjectStore):

    """Store for massive import of data, with delayed insertion of meta data.

    WARNINGS:

    - This store may only be used with PostgreSQL for now, as it relies

      on the COPY FROM method, and on specific PostgreSQL tables to get all

      the indexes.

    - This store can only insert relations that are not inlined (i.e.,

      which do *not* have inlined=True in their definition in the schema), unless they are

      specified as entity attributes.

    It should be used as follows:

       store = MassiveObjectStore(cnx)

       store.init_rtype_table('Person', 'lives_in', 'Location')

       ...

       store.prepare_insert_entity('Person', subj_iid_attribute=person_iid, ...)

       store.prepare_insert_entity('Location', obj_iid_attribute=location_iid, ...)

       ...

       # subj_iid_attribute and obj_iid_attribute are argument names

       # chosen by the user (e.g. "cwuri"). These names can be identical.

       # person_iid and location_iid are unique IDs and depend on the data

       # (e.g URI).

       store.flush()

       store.relate_by_iid(person_iid, 'lives_in', location_iid)

       # For example:

       store.prepare_insert_entity('Person',

                                   cwuri='http://dbpedia.org/toto',

                                   name='Toto')

       store.prepare_insert_entity('Location',

                                   uri='http://geonames.org/11111',

                                   name='Somewhere')

       store.flush()

       store.relate_by_iid('http://dbpedia.org/toto',

                           'lives_in',

                           'http://geonames.org/11111')

       # Finally

       store.convert_relations('Person', 'lives_in', 'Location',

                               'subj_iid_attribute', 'obj_iid_attribute')

       # For the previous example:

       store.convert_relations('Person', 'lives_in', 'Location', 'cwuri', 'uri')

       ...

       store.commit()

       store.finish()

    Full-text indexation is not handled, you'll have to reindex the proper entity types by yourself

    if desired.

    """

    # max size of the iid, used to create the iid_eid conversion table

    iid_maxsize = 1024

    def __init__(self, cnx,

                 on_commit_callback=None, on_rollback_callback=None,

                 slave_mode=False,

                 eids_seq_range=10000,

                 metagen=None):

        """ Create a MassiveObject store, with the following attributes:

        - cnx: CubicWeb cnx

        - eids_seq_range: size of eid range reserved by the store for each batch

        """

        super(MassiveObjectStore, self).__init__(cnx)

        self.on_commit_callback = on_commit_callback

        self.on_rollback_callback = on_rollback_callback

        self.slave_mode = slave_mode

        self.eids_seq_range = eids_seq_range

        if metagen is None:

            metagen = stores.MetadataGenerator(cnx)

        self.metagen = metagen

        self.logger = logging.getLogger('dataimport.massive_store')

        self.sql = cnx.system_sql

        self.schema = self._cnx.vreg.schema

        self.default_values = get_default_values(self.schema)

        self.get_next_eid = lambda g=self._get_eid_gen(): next(g)

        self._dbh = PGHelper(cnx)

        cnx.read_security = False

        cnx.write_security = False

        self._data_entities = defaultdict(list)

        self._data_relations = defaultdict(list)

        self._initialized = set()

        # uri handling

        self._data_uri_relations = defaultdict(list)

        # etypes for which we have a uri_eid_%(etype)s table

        self._init_uri_eid = set()

        # etypes for which we have a uri_eid_%(e)s_idx index

        self._uri_eid_inserted = set()

        # set of rtypes for which we have a %(rtype)s_relation_iid_tmp table

        self._uri_rtypes = set()

        if not self.slave_mode:

            # drop constraint and metadata table, they will be recreated when self.finish() is

            # called

            self._drop_all_constraints()

            self._drop_metatables_constraints()

    def _get_eid_gen(self):

        """ Function getting the next eid. This is done by preselecting

        a given number of eids from the 'entities_id_seq', and then

        storing them"""

        while True:

            last_eid = self._cnx.repo.system_source.create_eid(self._cnx, self.eids_seq_range)

            for eid in range(last_eid - self.eids_seq_range + 1, last_eid + 1):

                yield eid

    # URI related things #######################################################

    def init_rtype_table(self, etype_from, rtype, etype_to):

        """ Build temporary table for standard rtype """

        # Create an uri_eid table for each etype for a better control of which etype is concerned by

        # a particular possibly multivalued relation.

        for etype in (etype_from, etype_to):

            if etype and etype not in self._init_uri_eid:

                self._init_uri_eid.add(etype)

                self.sql('CREATE TABLE IF NOT EXISTS uri_eid_%(e)s'

                         '(uri character varying(%(size)s), eid integer)'

                         % {'e': etype.lower(), 'size': self.iid_maxsize})

        if rtype not in self._uri_rtypes:

            # Create the temporary table

            if not self.schema.rschema(rtype).inlined:

                self.sql('CREATE TABLE IF NOT EXISTS %(r)s_relation_iid_tmp'

                         '(uri_from character varying(%(s)s), uri_to character varying(%(s)s))'

                         % {'r': rtype, 's': self.iid_maxsize})

                self._uri_rtypes.add(rtype)

            else:

                self.logger.warning("inlined relation %s: cannot insert it", rtype)

    def relate_by_iid(self, iid_from, rtype, iid_to):

        """Add new relation based on the internal id (iid)

        of the entities (not the eid)"""

        # Push data

        if isinstance(iid_from, unicode):

            iid_from = iid_from.encode('utf-8')

        if isinstance(iid_to, unicode):

            iid_to = iid_to.encode('utf-8')

        self._data_uri_relations[rtype].append({'uri_from': iid_from, 'uri_to': iid_to})

    def flush_relations(self):

        """ Flush the relations data

        """

        for rtype, data in self._data_uri_relations.items():

            if not data:

                self.logger.info('No data for rtype %s', rtype)

            buf = StringIO('\n'.join(['%(uri_from)s\t%(uri_to)s' % d for d in data]))

            if not buf:

                self.logger.info('Empty Buffer for rtype %s', rtype)

                continue

            cursor = self._cnx.cnxset.cu

            if not self.schema.rschema(rtype).inlined:

                cursor.copy_from(buf, '%s_relation_iid_tmp' % rtype.lower(),

                                 null='NULL', columns=('uri_from', 'uri_to'))

            else:

                self.logger.warning("inlined relation %s: cannot insert it", rtype)

            buf.close()

            # Clear data cache

            self._data_uri_relations[rtype] = []

    def fill_uri_eid_table(self, etype, uri_label):

        """ Fill the uri_eid table

        """

        if etype not in self._uri_eid_inserted:

            self._uri_eid_inserted.add(etype)

            self.logger.info('Fill uri_eid for etype %s', etype)

            self.sql('INSERT INTO uri_eid_%(e)s SELECT cw_%(l)s, cw_eid FROM cw_%(e)s'

                     % {'l': uri_label, 'e': etype.lower()})

            self.sql('CREATE INDEX uri_eid_%(e)s_idx ON uri_eid_%(e)s(uri)'

                     % {'e': etype.lower()})

    def convert_relations(self, etype_from, rtype, etype_to,

                          uri_label_from='cwuri', uri_label_to='cwuri'):

        """ Flush the converted relations

        """

        # Always flush relations to be sure

        self.logger.info('Convert relations %s %s %s', etype_from, rtype, etype_to)

        self.flush_relations()

        if uri_label_from:

            self.fill_uri_eid_table(etype_from, uri_label_from)

        if uri_label_to:

            self.fill_uri_eid_table(etype_to, uri_label_to)

        if self.schema.rschema(rtype).inlined:

            self.logger.warning("Can't insert inlined relation %s", rtype)

            return

        if uri_label_from and uri_label_to:

            sql = '''INSERT INTO %(r)s_relation (eid_from, eid_to) SELECT DISTINCT O1.eid, O2.eid

            FROM %(r)s_relation_iid_tmp AS T, uri_eid_%(ef)s as O1, uri_eid_%(et)s as O2

            WHERE O1.uri=T.uri_from AND O2.uri=T.uri_to AND NOT EXISTS (

            SELECT 1 FROM %(r)s_relation AS TT WHERE TT.eid_from=O1.eid AND TT.eid_to=O2.eid);

            '''

        elif uri_label_to:

            sql = '''INSERT INTO %(r)s_relation (eid_from, eid_to) SELECT DISTINCT

            CAST(T.uri_from AS INTEGER), O1.eid

            FROM %(r)s_relation_iid_tmp AS T, uri_eid_%(et)s as O1

            WHERE O1.uri=T.uri_to AND NOT EXISTS (

            SELECT 1 FROM %(r)s_relation AS TT WHERE

            TT.eid_from=CAST(T.uri_from AS INTEGER) AND TT.eid_to=O1.eid);

            '''

        elif uri_label_from:

            sql = '''INSERT INTO %(r)s_relation (eid_from, eid_to) SELECT DISTINCT O1.eid, T.uri_to

            O1.eid, CAST(T.uri_to AS INTEGER)

            FROM %(r)s_relation_iid_tmp AS T, uri_eid_%(ef)s as O1

            WHERE O1.uri=T.uri_from AND NOT EXISTS (

            SELECT 1 FROM %(r)s_relation AS TT WHERE

            TT.eid_from=O1.eid AND TT.eid_to=CAST(T.uri_to AS INTEGER));

            '''

        try:

            self.sql(sql % {'r': rtype.lower(),

                            'et': etype_to.lower() if etype_to else u'',

                            'ef': etype_from.lower() if etype_from else u''})

        except Exception as ex:

            self.logger.error("Can't insert relation %s: %s", rtype, ex)

    # SQL utilities #########################################################

    def _drop_all_constraints(self):

        etypes_tables = ('cw_%s' % eschema.type.lower() for eschema in self.schema.entities()

                         if not eschema.final)

        rtypes_tables = ('%s_relation' % rschema.type.lower() for rschema in self.schema.relations()

                         if rschema_has_table(rschema, skip_relations=PURE_VIRTUAL_RTYPES))

        for tablename in chain(etypes_tables, rtypes_tables, ('entities',)):

            self._dbh.drop_constraints(tablename)

    def _drop_metatables_constraints(self):

        """ Drop all the constraints for the meta data"""

        for tablename in ('created_by_relation', 'owned_by_relation',

                          'is_instance_of_relation', 'is_relation',

                          'entities'):

            self._dbh.drop_indexes(tablename)

    def restart_eid_sequence(self, start_eid):

        self.sql(self._cnx.repo.system_source.dbhelper.sql_restart_numrange(

            'entities_id_seq', initial_value=start_eid))

        self._cnx.commit()

    # store api ################################################################

    def prepare_insert_entity(self, etype, **kwargs):

        """Given an entity type, attributes and inlined relations, returns the inserted entity's

        eid.

        """

        if not self.slave_mode and etype not in self._initialized:

            self._initialized.add(etype)

            self._dbh.drop_indexes('cw_%s' % etype.lower())

            self.sql('CREATE TABLE IF NOT EXISTS cwmassive_initialized'

                     '(retype text, type varchar(128))')

            self.sql("INSERT INTO cwmassive_initialized VALUES (%(e)s, 'etype')", {'e': etype})

            self.sql('ALTER TABLE cw_%s ADD COLUMN extid VARCHAR(256)' % etype.lower())

        attrs = self.metagen.base_etype_attrs(etype)

        data = copy(attrs)  # base_etype_attrs is @cached, a copy is necessary

        data.update(kwargs)

        if 'eid' not in data:

            # If eid is not given and the eids sequence is set, use the value from the sequence

            eid = self.get_next_eid()

            data['eid'] = eid

        # XXX default values could be set once for all in base entity

        default_values = self.default_values[etype]

        missing_keys = set(default_values) - set(data)

        data.update((key, default_values[key]) for key in missing_keys)

        extid = self.metagen.entity_extid(etype, data['eid'], data)

        if extid is not None:

            extid = b64encode(extid).decode('ascii')

        data['extid'] = extid

        self.metagen.init_entity_attrs(etype, data['eid'], data)

        self._data_entities[etype].append(data)

        return data['eid']

    def prepare_insert_relation(self, eid_from, rtype, eid_to, **kwargs):

        """Insert into the database a  relation ``rtype`` between entities with eids ``eid_from``

        and ``eid_to``.

        Relation must not be inlined.

        """

        if not self.slave_mode and rtype not in self._initialized:

            assert not self._cnx.vreg.schema.rschema(rtype).inlined

            self._initialized.add(rtype)

            self._dbh.drop_indexes('%s_relation' % rtype.lower())

            self.sql('CREATE TABLE %s_relation_tmp (eid_from integer, eid_to integer)'

                     % rtype.lower())

            self.sql('CREATE TABLE IF NOT EXISTS cwmassive_initialized'

                     '(retype text, type varchar(128))')

            self.sql("INSERT INTO cwmassive_initialized VALUES (%(e)s, 'rtype')", {'e': rtype})

        self._data_relations[rtype].append({'eid_from': eid_from, 'eid_to': eid_to})

    def flush(self):

        """Flush the data"""

        self.flush_entities()

        self.flush_internal_relations()

        self.flush_relations()

    def commit(self):

        """Commit the database transaction."""

        self.on_commit()

        super(MassiveObjectStore, self).commit()

    def finish(self):

        """Remove temporary tables and columns."""

        self.logger.info("Start cleaning")

        if self.slave_mode:

            raise RuntimeError('Store cleanup is not allowed in slave mode')

        self.logger.info("Start cleaning")

        # Cleanup relations tables

        for etype in self._init_uri_eid:

            self.sql('DROP TABLE uri_eid_%s' % etype.lower())

        # Remove relations tables

        for rtype in self._uri_rtypes:

            self.sql('DROP TABLE %(r)s_relation_iid_tmp' % {'r': rtype})

        # Get all the initialized etypes/rtypes

        if self._dbh.table_exists('cwmassive_initialized'):

            cu = self.sql('SELECT retype, type FROM cwmassive_initialized')

            for retype, _type in cu.fetchall():

                self.logger.info('Cleanup for %s' % retype)

                if _type == 'etype':

                    self.sql('ALTER TABLE cw_%s DROP COLUMN extid' % retype)

                elif _type == 'rtype':

                    # Cleanup relations tables

                    self._cleanup_relations(retype)

                self.sql('DELETE FROM cwmassive_initialized WHERE retype = %(e)s',

                         {'e': retype})

        self._dbh.restore_indexes_and_constraints()

        # Delete the meta data table

        self.sql('DROP TABLE IF EXISTS cwmassive_initialized')

        self.commit()

    # FLUSH #################################################################

    def on_commit(self):

        if self.on_commit_callback:

            self.on_commit_callback()

    def on_rollback(self, exc, etype, data):

        if self.on_rollback_callback:

            self.on_rollback_callback(exc, etype, data)

            self._cnx.rollback()

        else:

            raise exc

    def flush_internal_relations(self):

        """ Flush the relations data

        """

        for rtype, data in self._data_relations.items():

            if not data:

                # There is no data for these etype for this flush round.

                continue

            buf = pgstore._create_copyfrom_buffer(data, ('eid_from', 'eid_to'))