# copyright 2014 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/>.

"""Helper functions for migrations that aren't reliable enough or too dangerous

to be available in the standard migration environment

"""

from __future__ import print_function

__docformat__ = "restructuredtext en"

def drop_entity_types_fast(*etypes, **kwargs):

    """drop an entity type bypassing all hooks

    here be dragons.

    """

    # XXX cascade deletion through composite relations?

    for etype in etypes:

        if etype not in schema:

            print('%s does not exist' % etype)

            continue

        etype = schema[etype]

        # ignore attributes and inlined rels since they'll be dropped anyway

        srels = [x.type for x in etype.subject_relations() if x.eid and not (x.final or x.inlined)]

        orels = [x.type for x in etype.object_relations() if x.eid and not x.inlined]

        inlined_rels = [x for x in etype.object_relations() if x.eid and x.inlined]

        # eids to be deleted could be listed in some other entity tables through inlined relations

        for rtype in inlined_rels:

            for subjtype in rtype.subjects(etype):

                if subjtype in etypes:

                    continue

                sql('UPDATE cw_%(stype)s SET cw_%(rtype)s = NULL '

                    'WHERE cw_%(rtype)s IN (SELECT eid FROM entities WHERE type = %%s)' %

                    {'stype': subjtype.type, 'rtype': rtype.type},

                    (etype.type,))

        for rel in srels:

            if all(subj in etypes for subj in rel.subjects()) or all(obj in etypes for obj in rel.objects()):

                sql('DELETE FROM %s_relation' % rel.type)

            else:

                sql('DELETE FROM %s_relation WHERE eid_from IN (SELECT eid FROM entities WHERE type = %%s)' % rel.type, (etype.type,))

        for rel in orels:

            if all(subj in etypes for subj in rel.subjects()) or all(obj in etypes for obj in rel.objects()):

                sql('DELETE FROM %s_relation' % rel.type)

            else:

                sql('DELETE FROM %s_relation WHERE eid_to IN (SELECT eid FROM entities WHERE type = %%s)' % rel, (etype.type,))

        sql('DELETE FROM appears WHERE uid IN (SELECT eid FROM entities WHERE type = %s)', (etype.type,))

        sql('DELETE FROM cw_%s' % etype.type)

        sql('DELETE FROM entities WHERE type = %s', (etype.type,))

    for etype in etypes:

        drop_entity_type(etype, **kwargs)