# Copyright (C) 2012-2014 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman 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 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman 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
# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.

"""Database factory."""

from __future__ import absolute_import, print_function, unicode_literals

__metaclass__ = type
__all__ = [
    'DatabaseFactory',
    'DatabaseTestingFactory',
    ]


import os
import types

from alembic.config import Config
from alembic import command

from flufl.lock import Lock
from zope.interface import implementer
from zope.interface.verify import verifyObject

from mailman.config import config
from mailman.database.model import Model
from mailman.interfaces.database import IDatabase, IDatabaseFactory
from mailman.utilities.modules import call_name


alembic_cfg = Config("./alembic.ini")


@implementer(IDatabaseFactory)
class DatabaseFactory:
    """Create a new database."""

    @staticmethod
    def create():
        """See `IDatabaseFactory`."""
        with Lock(os.path.join(config.LOCK_DIR, 'dbcreate.lck')):
            database_class = config.database['class']
            database = call_name(database_class)
            verifyObject(IDatabase, database)
            database.initialize()
            Model.metadata.create_all(database.engine)
            command.stamp(alembic_cfg, "head")
            database.commit()
            return database



def _reset(self):
    """See `IDatabase`."""
    # Avoid a circular import at module level.
    from mailman.database.model import Model
    self.store.rollback()
    self._pre_reset(self.store)
    Model._reset(self)
    self._post_reset(self.store)
    self.store.commit()


@implementer(IDatabaseFactory)
class DatabaseTestingFactory:
    """Create a new database for testing."""

    @staticmethod
    def create():
        """See `IDatabaseFactory`."""
        database_class = config.database['class']
        database = call_name(database_class)
        verifyObject(IDatabase, database)
        database.initialize()
        Model.metadata.create_all(database.engine)
        command.stamp(alembic_cfg, "head")
        database.commit()
        # Make _reset() a bound method of the database instance.
        database._reset = types.MethodType(_reset, database)
        return database