# Copyright 2014 IBM Corp.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

import glob
import os
from unittest import mock
import urllib

from alembic.runtime import migration as alembic_migration
from migrate import exceptions as migrate_exceptions
from migrate.versioning import api as migrate_api

from nova.db.api import api as api_db_api
from nova.db.main import api as main_db_api
from nova.db import migration
from nova import exception
from nova import test
from nova.tests import fixtures as nova_fixtures


class TestDBURL(test.NoDBTestCase):
    USES_DB_SELF = True

    def test_db_sync_with_special_symbols_in_connection_string(self):
        qargs = 'read_default_group=data with/a+percent_%-and%20symbols!'
        url = f"sqlite:///:memory:?{qargs}"
        self.flags(connection=url, group='database')
        self.useFixture(nova_fixtures.Database())

        alembic_config = migration._find_alembic_conf()
        with mock.patch.object(
                migration, '_find_alembic_conf', return_value=alembic_config):
            migration.db_sync()
        actual = alembic_config.get_main_option('sqlalchemy.url')
        expected = (
            "sqlite:///:memory:?read_default_group=data+with%2Fa"
            "+percent_%25-and+symbols%21"
        )
        self.assertEqual(expected, actual)
        self.assertEqual(
            urllib.parse.unquote_plus(url),
            urllib.parse.unquote_plus(actual)
        )


class TestDBSync(test.NoDBTestCase):

    def test_db_sync_invalid_database(self):
        """We only have two databases."""
        self.assertRaises(
            exception.Invalid, migration.db_sync, database='invalid')

    def test_db_sync_legacy_version(self):
        """We don't allow users to request legacy versions."""
        self.assertRaises(
            exception.Invalid,
            migration.db_sync, '402')

    @mock.patch.object(migration, '_upgrade_alembic')
    @mock.patch.object(migration, '_init_alembic_on_legacy_database')
    @mock.patch.object(migration, '_is_database_under_alembic_control')
    @mock.patch.object(migration, '_is_database_under_migrate_control')
    @mock.patch.object(migration, '_find_alembic_conf')
    @mock.patch.object(migration, '_find_migrate_repo')
    @mock.patch.object(migration, '_get_engine')
    def _test_db_sync(
        self, has_migrate, has_alembic, mock_get_engine, mock_find_repo,
        mock_find_conf, mock_is_migrate, mock_is_alembic, mock_init,
        mock_upgrade,
    ):

        # return an encoded URL to mimic sqlalchemy
        mock_get_engine.return_value.url = (
           'mysql+pymysql://nova:pass@192.168.24.3/nova?'
           'read_default_file=%2Fetc%2Fmy.cnf.d%2Fnova.cnf'
           '&read_default_group=nova'
       )
        mock_is_migrate.return_value = has_migrate
        mock_is_alembic.return_value = has_alembic

        migration.db_sync()

        mock_get_engine.assert_called_once_with('main', context=None)
        mock_find_repo.assert_called_once_with('main')
        mock_find_conf.assert_called_once_with('main')
        mock_find_conf.return_value.set_main_option.assert_called_once_with(
            'sqlalchemy.url',
            'mysql+pymysql://nova:pass@192.168.24.3/nova?'  # ...
            'read_default_file=%%2Fetc%%2Fmy.cnf.d%%2Fnova.cnf'  # ...
            '&read_default_group=nova'
        )
        mock_is_migrate.assert_called_once_with(
            mock_get_engine.return_value, mock_find_repo.return_value)

        if has_migrate:
            mock_is_alembic.assert_called_once_with(
                mock_get_engine.return_value)
        else:
            mock_is_alembic.assert_not_called()

        # we should only attempt the upgrade of the remaining
        # sqlalchemy-migrate-based migrations and fake apply of the initial
        # alembic migrations if sqlalchemy-migrate is in place but alembic
        # hasn't been used yet
        if has_migrate and not has_alembic:
            mock_init.assert_called_once_with(
                mock_get_engine.return_value, 'main',
                mock_find_repo.return_value, mock_find_conf.return_value)
        else:
            mock_init.assert_not_called()

        # however, we should always attempt to upgrade the requested migration
        # to alembic
        mock_upgrade.assert_called_once_with(
            mock_get_engine.return_value, mock_find_conf.return_value, None)

    def test_db_sync_new_deployment(self):
        """Mimic a new deployment without existing sqlalchemy-migrate cruft."""
        has_migrate = False
        has_alembic = False
        self._test_db_sync(has_migrate, has_alembic)

    def test_db_sync_with_existing_migrate_database(self):
        """Mimic a deployment currently managed by sqlalchemy-migrate."""
        has_migrate = True
        has_alembic = False
        self._test_db_sync(has_migrate, has_alembic)

    def test_db_sync_with_existing_alembic_database(self):
        """Mimic a deployment that's already switched to alembic."""
        has_migrate = True
        has_alembic = True
        self._test_db_sync(has_migrate, has_alembic)


@mock.patch.object(alembic_migration.MigrationContext, 'configure')
@mock.patch.object(migrate_api, 'db_version')
@mock.patch.object(migration, '_is_database_under_alembic_control')
@mock.patch.object(migration, '_is_database_under_migrate_control')
@mock.patch.object(migration, '_get_engine')
@mock.patch.object(migration, '_find_migrate_repo')
class TestDBVersion(test.NoDBTestCase):

    def test_db_version_invalid_database(
        self, mock_find_repo, mock_get_engine, mock_is_migrate,
        mock_is_alembic, mock_migrate_version, mock_m_context_configure,
    ):
        """We only have two databases."""
        self.assertRaises(
            exception.Invalid, migration.db_version, database='invalid')

    def test_db_version_migrate(
        self, mock_find_repo, mock_get_engine, mock_is_migrate,
        mock_is_alembic, mock_migrate_version, mock_m_context_configure,
    ):
        """Database is controlled by sqlalchemy-migrate."""
        mock_is_migrate.return_value = True
        mock_is_alembic.return_value = False

        ret = migration.db_version('main')
        self.assertEqual(mock_migrate_version.return_value, ret)

        mock_find_repo.assert_called_once_with('main')
        mock_get_engine.assert_called_once_with('main', context=None)
        mock_is_migrate.assert_called_once()
        mock_is_alembic.assert_called_once()
        mock_migrate_version.assert_called_once_with(
            mock_get_engine.return_value, mock_find_repo.return_value)
        mock_m_context_configure.assert_not_called()

    def test_db_version_alembic(
        self, mock_find_repo, mock_get_engine, mock_is_migrate,
        mock_is_alembic, mock_migrate_version, mock_m_context_configure,
    ):
        """Database is controlled by alembic."""
        mock_is_migrate.return_value = False
        mock_is_alembic.return_value = True

        ret = migration.db_version('main')
        mock_m_context = mock_m_context_configure.return_value
        self.assertEqual(
            mock_m_context.get_current_revision.return_value,
            ret
        )

        mock_find_repo.assert_called_once_with('main')
        mock_get_engine.assert_called_once_with('main', context=None)
        mock_is_migrate.assert_called_once()
        mock_is_alembic.assert_called_once()
        mock_migrate_version.assert_not_called()
        mock_m_context_configure.assert_called_once()

    def test_db_version_not_controlled(
        self, mock_find_repo, mock_get_engine, mock_is_migrate,
        mock_is_alembic, mock_migrate_version, mock_m_context_configure,
    ):
        """Database is not controlled."""
        mock_is_migrate.return_value = False
        mock_is_alembic.return_value = False

        ret = migration.db_version()
        self.assertIsNone(ret)

        mock_find_repo.assert_called_once_with('main')
        mock_get_engine.assert_called_once_with('main', context=None)
        mock_is_migrate.assert_called_once()
        mock_is_alembic.assert_called_once()
        mock_migrate_version.assert_not_called()
        mock_m_context_configure.assert_not_called()


class TestGetEngine(test.NoDBTestCase):

    def test_get_main_engine(self):
        with mock.patch.object(
            main_db_api, 'get_engine', return_value='engine',
        ) as mock_get_engine:
            engine = migration._get_engine()
            self.assertEqual('engine', engine)
            mock_get_engine.assert_called_once_with(context=None)

    def test_get_api_engine(self):
        with mock.patch.object(
            api_db_api, 'get_engine', return_value='engine',
        ) as mock_get_engine:
            engine = migration._get_engine('api')
            self.assertEqual('engine', engine)
            mock_get_engine.assert_called_once_with()


class TestDatabaseUnderVersionControl(test.NoDBTestCase):

    @mock.patch.object(migrate_api, 'db_version')
    def test__is_database_under_migrate_control__true(self, mock_db_version):
        ret = migration._is_database_under_migrate_control('engine', 'repo')
        self.assertTrue(ret)

        mock_db_version.assert_called_once_with('engine', 'repo')

    @mock.patch.object(migrate_api, 'db_version')
    def test__is_database_under_migrate_control__false(self, mock_db_version):
        mock_db_version.side_effect = \
            migrate_exceptions.DatabaseNotControlledError()

        ret = migration._is_database_under_migrate_control('engine', 'repo')
        self.assertFalse(ret)

        mock_db_version.assert_called_once_with('engine', 'repo')

    @mock.patch.object(alembic_migration.MigrationContext, 'configure')
    def test__is_database_under_alembic_control__true(self, mock_configure):
        context = mock_configure.return_value
        context.get_current_revision.return_value = 'foo'
        engine = mock.MagicMock()

        ret = migration._is_database_under_alembic_control(engine)
        self.assertTrue(ret)

        context.get_current_revision.assert_called_once_with()

    @mock.patch.object(alembic_migration.MigrationContext, 'configure')
    def test__is_database_under_alembic_control__false(self, mock_configure):
        context = mock_configure.return_value
        context.get_current_revision.return_value = None
        engine = mock.MagicMock()

        ret = migration._is_database_under_alembic_control(engine)
        self.assertFalse(ret)

        context.get_current_revision.assert_called_once_with()


class ProjectTestCase(test.NoDBTestCase):

    def test_no_migrations_have_downgrade(self):
        topdir = os.path.normpath(os.path.dirname(__file__) + '/../../../')
        # Walk both the nova_api and nova (cell) database migrations.
        includes_downgrade = []
        for directory in (
            os.path.join(topdir, 'db', 'main', 'legacy_migrations'),
            os.path.join(topdir, 'db', 'api', 'legacy_migrations'),
        ):
            py_glob = os.path.join(directory, 'versions', '*.py')
            for path in glob.iglob(py_glob):
                has_upgrade = False
                has_downgrade = False
                with open(path, "r") as f:
                    for line in f:
                        if 'def upgrade(' in line:
                            has_upgrade = True
                        if 'def downgrade(' in line:
                            has_downgrade = True

                    if has_upgrade and has_downgrade:
                        fname = os.path.basename(path)
                        includes_downgrade.append(fname)

        helpful_msg = (
            "The following migrations have a downgrade "
            "which is not supported:"
            "\n\t%s" % '\n\t'.join(sorted(includes_downgrade)))
        self.assertFalse(includes_downgrade, helpful_msg)