# -*- coding: utf-8 -*-
#
# This file is part of Invenio.
# Copyright (C) 2015 CERN.
#
# Invenio 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; either version 2 of the
# License, or (at your option) any later version.
#
# Invenio 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 Invenio; if not, write to the
# Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA 02111-1307, USA.
#
# In applying this license, CERN does not
# waive the privileges and immunities granted to it by virtue of its status
# as an Intergovernmental Organization or submit itself to any jurisdiction.

"""Shared database object for Invenio."""

from flask_sqlalchemy import SQLAlchemy as FlaskSQLAlchemy


class SQLAlchemy(FlaskSQLAlchemy):
    """Implement or overide extension methods."""

    def apply_driver_hacks(self, app, info, options):
        """Called before engine creation."""
        # Don't forget to apply hacks defined on parent object.
        super(SQLAlchemy, self).apply_driver_hacks(app, info, options)

        if info.drivername == 'sqlite':
            connect_args = options.setdefault('connect_args', {})

            if 'isolation_level' not in connect_args:
                # disable pysqlite's emitting of the BEGIN statement entirely.
                # also stops it from emitting COMMIT before any DDL.
                connect_args['isolation_level'] = None


db = SQLAlchemy()
"""Shared database instance using Flask-SQLAlchemy extension.

This object is initialized during initialization of ``InvenioDB``
extenstion that takes care about loading all entrypoints from key
``invenio_db.models``.
"""
