# copyright 2003-2016 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/>.

"""Postgres specific store"""

import warnings

import os.path as osp

from io import StringIO

from time import asctime

from datetime import date, datetime, time

from collections import defaultdict

from cubicweb.utils import make_uid

from cubicweb.server.sqlutils import SQL_PREFIX

from cubicweb.dataimport.stores import NoHookRQLObjectStore

def _execmany_thread_not_copy_from(cu, statement, data, table=None,

                                   columns=None, encoding='utf-8'):

    """ Execute thread without copy from

    """

    cu.executemany(statement, data)

def _execmany_thread_copy_from(cu, statement, data, table,

                               columns, encoding='utf-8'):

    """ Execute thread with copy from

    """

    try:

        buf = _create_copyfrom_buffer(data, columns, encoding=encoding)

    except ValueError:

        _execmany_thread_not_copy_from(cu, statement, data)

    else:

        if columns is None:

            cu.copy_from(buf, table, null=u'NULL')

        else:

            cu.copy_from(buf, table, null=u'NULL', columns=columns)

def _execmany_thread(sql_connect, statements, dump_output_dir=None,

                     support_copy_from=True, encoding='utf-8'):

    """

    Execute sql statement. If 'INSERT INTO', try to use 'COPY FROM' command,

    or fallback to execute_many.

    """

    if support_copy_from:

        execmany_func = _execmany_thread_copy_from

    else:

        execmany_func = _execmany_thread_not_copy_from

    cnx = sql_connect()

    cu = cnx.cursor()

    try:

        for statement, data in statements:

            table = None

            columns = None

            try:

                if not statement.startswith('INSERT INTO'):

                    cu.executemany(statement, data)

                    continue

                table = statement.split()[2]

                if isinstance(data[0], (tuple, list)):

                    columns = None

                else:

                    columns = list(data[0])

                execmany_func(cu, statement, data, table, columns, encoding)

            except Exception:

                print('unable to copy data into table %s' % table)

                # Error in import statement, save data in dump_output_dir

                if dump_output_dir is not None:

                    pdata = {'data': data, 'statement': statement,

                             'time': asctime(), 'columns': columns}

                    filename = make_uid()

                    try:

                        with open(osp.join(dump_output_dir,

                                           '%s.pickle' % filename), 'wb') as fobj:

                            pickle.dump(pdata, fobj)

                    except IOError:

                        print('ERROR while pickling in', dump_output_dir, filename+'.pickle')

                cnx.rollback()

                raise

    finally:

        cnx.commit()

        cu.close()

def _copyfrom_buffer_convert_None(value, **opts):

    '''Convert None value to "NULL"'''

    return u'NULL'

def _copyfrom_buffer_convert_number(value, **opts):

    '''Convert a number into its string representation'''

def _copyfrom_buffer_convert_string(value, **opts):

    '''Convert string value.

    '''

    escape_chars = ((u'\\', u'\\\\'), (u'\t', u'\\t'), (u'\r', u'\\r'),

                    (u'\n', u'\\n'))

    for char, replace in escape_chars:

        value = value.replace(char, replace)

    return value

def _copyfrom_buffer_convert_date(value, **opts):

    '''Convert date into "YYYY-MM-DD"'''

    # Do not use strftime, as it yields issue with date < 1900

    # (http://bugs.python.org/issue1777412)

    return u'%04d-%02d-%02d' % (value.year, value.month, value.day)

def _copyfrom_buffer_convert_datetime(value, **opts):

    '''Convert date into "YYYY-MM-DD HH:MM:SS.UUUUUU"'''

    # Do not use strftime, as it yields issue with date < 1900

    # (http://bugs.python.org/issue1777412)

    return u'%s %s' % (_copyfrom_buffer_convert_date(value, **opts),

                       _copyfrom_buffer_convert_time(value, **opts))

def _copyfrom_buffer_convert_time(value, **opts):

    '''Convert time into "HH:MM:SS.UUUUUU"'''

    return u'%02d:%02d:%02d.%06d' % (value.hour, value.minute,

                                     value.second, value.microsecond)

# (types, converter) list.

_COPYFROM_BUFFER_CONVERTERS = [

    (type(None), _copyfrom_buffer_convert_None),

    (datetime, _copyfrom_buffer_convert_datetime),

    (date, _copyfrom_buffer_convert_date),

    (time, _copyfrom_buffer_convert_time),

]

def _create_copyfrom_buffer(data, columns=None, **convert_opts):

    """

    Create a StringIO buffer for 'COPY FROM' command.

    Deals with Unicode, Int, Float, Date... (see ``converters``)

    :data: a sequence/dict of tuples

    :columns: list of columns to consider (default to all columns)

    :converter_opts: keyword arguements given to converters

    """

    # Create a list rather than directly create a StringIO

    # to correctly write lines separated by '\n' in a single step

    rows = []

    if columns is None:

        if isinstance(data[0], (tuple, list)):

            columns = list(range(len(data[0])))

        elif isinstance(data[0], dict):

            columns = data[0].keys()

        else:

            raise ValueError('Could not get columns: you must provide columns.')

    for row in data:

        # Iterate over the different columns and the different values

        # and try to convert them to a correct datatype.

        # If an error is raised, do not continue.

        formatted_row = []

        for col in columns:

            try:

                value = row[col]

            except KeyError:

                warnings.warn(u"Column %s is not accessible in row %s"

                              % (col, row), RuntimeWarning)

                # XXX 'value' set to None so that the import does not end in

                # error.

                # Instead, the extra keys are set to NULL from the

                # database point of view.

                value = None

            for types, converter in _COPYFROM_BUFFER_CONVERTERS:

                if isinstance(value, types):

                    value = converter(value, **convert_opts)

                    break

            else:

                raise ValueError("Unsupported value type %s" % type(value))

            # We push the value to the new formatted row

            # if the value is not None and could be converted to a string.

            formatted_row.append(value)

        rows.append('\t'.join(formatted_row))

    return StringIO('\n'.join(rows))

###########################################################################

## SQL Source #############################################################

###########################################################################

class SQLGenSourceWrapper(object):

    def __init__(self, system_source, schema,

                 dump_output_dir=None):

        self.system_source = system_source

        # Explicitely backport attributes from system source

        self._storage_handler = self.system_source._storage_handler

        self.preprocess_entity = self.system_source.preprocess_entity

        self.sqlgen = self.system_source.sqlgen

        self.uri = self.system_source.uri

        self.eid = self.system_source.eid

        # Directory to write temporary files

        self.dump_output_dir = dump_output_dir

        # Allow to execute code with SQLite backend that does

        # not support (yet...) copy_from

        # XXX Should be dealt with in logilab.database

        spcfrom = system_source.dbhelper.dbapi_module.support_copy_from

        self.support_copy_from = spcfrom

        self.dbencoding = system_source.dbhelper.dbencoding

        self.init_statement_lists()

        self._inlined_rtypes_cache = {}

        self._fill_inlined_rtypes_cache(schema)

        self.schema = schema

        self.do_fti = False

    def _fill_inlined_rtypes_cache(self, schema):

        cache = self._inlined_rtypes_cache

        for eschema in schema.entities():

            for rschema in eschema.ordered_relations():

                if rschema.inlined:

                    cache[eschema.type] = SQL_PREFIX + rschema.type

    def init_statement_lists(self):

        self._sql_entities = defaultdict(list)

        self._sql_relations = {}

        self._sql_inlined_relations = {}

        self._sql_eids = defaultdict(list)

        # keep track, for each eid of the corresponding data dict

        self._sql_eid_insertdicts = {}

    def flush(self):

        print('starting flush')

        _entities_sql = self._sql_entities

        _relations_sql = self._sql_relations

        _inlined_relations_sql = self._sql_inlined_relations

        _insertdicts = self._sql_eid_insertdicts

        try:

            # try, for each inlined_relation, to find if we're also creating

            # the host entity (i.e. the subject of the relation).

            # In that case, simply update the insert dict and remove

            # the need to make the

            # UPDATE statement

            for statement, datalist in _inlined_relations_sql.items():

                new_datalist = []

                # for a given inlined relation,

                # browse each couple to be inserted

                for data in datalist:

                    keys = list(data)

                    # For inlined relations, it exists only two case:

                    # (rtype, cw_eid) or (cw_eid, rtype)

                    if keys[0] == 'cw_eid':

                        rtype = keys[1]

                    else:

                        rtype = keys[0]

                    updated_eid = data['cw_eid']

                    if updated_eid in _insertdicts:

                        _insertdicts[updated_eid][rtype] = data[rtype]

                    else:

                        # could not find corresponding insert dict, keep the

                        # UPDATE query

                        new_datalist.append(data)

                _inlined_relations_sql[statement] = new_datalist

            _execmany_thread(self.system_source.get_connection,

                             list(self._sql_eids.items())

                             + list(_entities_sql.items())

                             + list(_relations_sql.items())

                             + list(_inlined_relations_sql.items()),

                             dump_output_dir=self.dump_output_dir,

                             support_copy_from=self.support_copy_from,

                             encoding=self.dbencoding)

        finally:

            _entities_sql.clear()

            _relations_sql.clear()

            _insertdicts.clear()

            _inlined_relations_sql.clear()

    def add_relation(self, cnx, subject, rtype, object,

                     inlined=False, **kwargs):

        if inlined:

            _sql = self._sql_inlined_relations

            data = {'cw_eid': subject, SQL_PREFIX + rtype: object}

            subjtype = kwargs.get('subjtype')

            if subjtype is None:

                # Try to infer it

                targets = [t.type for t in

                           self.schema.rschema(rtype).subjects()]

                if len(targets) == 1:

                    subjtype = targets[0]

                else:

                    raise ValueError('You should give the subject etype for '

                                     'inlined relation %s'

                                     ', as it cannot be inferred: '

                                     'this type is given as keyword argument '

                                     '``subjtype``' % rtype)

            statement = self.sqlgen.update(SQL_PREFIX + subjtype,

                                           data, ['cw_eid'])

        else:

            _sql = self._sql_relations

            data = {'eid_from': subject, 'eid_to': object}

            statement = self.sqlgen.insert('%s_relation' % rtype, data)

        if statement in _sql:

            _sql[statement].append(data)

        else:

            _sql[statement] = [data]

    def add_entity(self, cnx, entity):

        with self._storage_handler(cnx, entity, 'added'):

            attrs = self.preprocess_entity(entity)

            rtypes = self._inlined_rtypes_cache.get(entity.cw_etype, ())

            if isinstance(rtypes, str):

                rtypes = (rtypes,)

            for rtype in rtypes:

                if rtype not in attrs:

                    attrs[rtype] = None

            sql = self.sqlgen.insert(SQL_PREFIX + entity.cw_etype, attrs)

            self._sql_eid_insertdicts[entity.eid] = attrs

            self._append_to_entities(sql, attrs)

    def _append_to_entities(self, sql, attrs):

        self._sql_entities[sql].append(attrs)

    def _handle_insert_entity_sql(self, cnx, sql, attrs):

        self._sql_eids[sql].append(attrs)

    def _handle_is_relation_sql(self, cnx, sql, attrs):

        self._append_to_entities(sql, attrs)

    def _handle_is_instance_of_sql(self, cnx, sql, attrs):

        self._append_to_entities(sql, attrs)

    def _handle_source_relation_sql(self, cnx, sql, attrs):

        self._append_to_entities(sql, attrs)

    # add_info is _copypasted_ from the one in NativeSQLSource. We want it

    # there because it will use the _handlers of the SQLGenSourceWrapper, which

    # are not like the ones in the native source.

    def add_info(self, cnx, entity, source):

        """add type and source info for an eid into the system table"""

        # begin by inserting eid/type/source into the entities table

        attrs = {'type': entity.cw_etype, 'eid': entity.eid}

        self._handle_insert_entity_sql(cnx, self.sqlgen.insert('entities', attrs), attrs)

        # insert core relations: is, is_instance_of and cw_source

        self._handle_is_relation_sql(cnx, 'INSERT INTO is_relation(eid_from,eid_to) VALUES (%s,%s)',

                                     (entity.eid, entity.e_schema.eid))

        for eschema in entity.e_schema.ancestors() + [entity.e_schema]:

            self._handle_is_relation_sql(cnx,

                                         'INSERT INTO is_instance_of_relation(eid_from,eid_to) VALUES (%s,%s)',

                                         (entity.eid, eschema.eid))

        self._handle_is_relation_sql(cnx, 'INSERT INTO cw_source_relation(eid_from,eid_to) VALUES (%s,%s)',

                                     (entity.eid, source.eid))

        # now we can update the full text index

        if self.do_fti and self.need_fti_indexation(entity.cw_etype):

            self.index_entity(cnx, entity=entity)