#    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 os
import testresources
import testscenarios
import unittest
from unittest import mock

from oslo_db.sqlalchemy import enginefacade
from oslo_db.sqlalchemy import provision
from oslo_db.sqlalchemy import test_fixtures
from oslo_db.tests import base as test_base

start_dir = os.path.dirname(__file__)


class BackendSkipTest(test_base.BaseTestCase):

    def test_skip_no_dbapi(self):

        class FakeDatabaseOpportunisticFixture(
                test_fixtures.OpportunisticDbFixture):
            DRIVER = 'postgresql'

        class SomeTest(test_fixtures.OpportunisticDBTestMixin,
                       test_base.BaseTestCase):
            FIXTURE = FakeDatabaseOpportunisticFixture

            def runTest(self):
                pass

        st = SomeTest()

        # patch in replacement lookup dictionaries to avoid
        # leaking from/to other tests
        with mock.patch(
                "oslo_db.sqlalchemy.provision."
                "Backend.backends_by_database_type", {
                    "postgresql":
                    provision.Backend("postgresql", "postgresql://")}):
            st._database_resources = {}
            st._db_not_available = {}
            st._schema_resources = {}

            with mock.patch(
                    "sqlalchemy.create_engine",
                    mock.Mock(side_effect=ImportError())):

                self.assertEqual([], st.resources)

                ex = self.assertRaises(
                    self.skipException,
                    st.setUp
                )

        self.assertEqual(
            "Backend 'postgresql' is unavailable: No DBAPI installed",
            str(ex)
        )

    def test_skip_no_such_backend(self):

        class FakeDatabaseOpportunisticFixture(
                test_fixtures.OpportunisticDbFixture):
            DRIVER = 'postgresql+nosuchdbapi'

        class SomeTest(test_fixtures.OpportunisticDBTestMixin,
                       test_base.BaseTestCase):

            FIXTURE = FakeDatabaseOpportunisticFixture

            def runTest(self):
                pass

        st = SomeTest()

        ex = self.assertRaises(
            self.skipException,
            st.setUp
        )

        self.assertEqual(
            "Backend 'postgresql+nosuchdbapi' is unavailable: No such backend",
            str(ex)
        )


class EnginefacadeIntegrationTest(test_base.BaseTestCase):
    def test_db_fixture(self):
        normal_mgr = enginefacade.transaction_context()
        normal_mgr.configure(
            connection="sqlite://",
            sqlite_fk=True,
            mysql_sql_mode="FOOBAR",
            max_overflow=38
        )

        class MyFixture(test_fixtures.OpportunisticDbFixture):
            def get_enginefacade(self):
                return normal_mgr

        test = mock.Mock(SCHEMA_SCOPE=None)
        fixture = MyFixture(test=test)
        resources = fixture._get_resources()

        testresources.setUpResources(test, resources, None)
        self.addCleanup(
            testresources.tearDownResources,
            test, resources, None
        )
        fixture.setUp()
        self.addCleanup(fixture.cleanUp)

        self.assertTrue(normal_mgr._factory._started)

        test.engine = normal_mgr.writer.get_engine()
        self.assertEqual("sqlite://", str(test.engine.url))
        self.assertIs(test.engine, normal_mgr._factory._writer_engine)
        engine_args = normal_mgr._factory._engine_args_for_conf(None)
        self.assertTrue(engine_args['sqlite_fk'])
        self.assertEqual("FOOBAR", engine_args["mysql_sql_mode"])
        self.assertEqual(38, engine_args["max_overflow"])

        fixture.cleanUp()
        fixture._clear_cleanups()  # so the real cleanUp works
        self.assertFalse(normal_mgr._factory._started)


class TestLoadHook(unittest.TestCase):
    """Test the 'load_tests' hook supplied by test_base.

    The purpose of this loader is to organize tests into an
    OptimisingTestSuite using the standard unittest load_tests hook.
    The hook needs to detect if it is being invoked at the module
    level or at the package level.  It has to behave completely differently
    in these two cases.

    """

    def test_module_level(self):
        load_tests = test_fixtures.optimize_module_test_loader()

        loader = unittest.TestLoader()

        found_tests = loader.discover(start_dir, pattern="test_fixtures.py")
        new_loader = load_tests(loader, found_tests, "test_fixtures.py")

        self.assertIsInstance(new_loader, testresources.OptimisingTestSuite)

        actual_tests = unittest.TestSuite(
            testscenarios.generate_scenarios(found_tests)
        )

        self.assertEqual(
            new_loader.countTestCases(), actual_tests.countTestCases()
        )

    def test_package_level(self):
        self._test_package_level(test_fixtures.optimize_package_test_loader)

    def _test_package_level(self, fn):
        load_tests = fn(
            os.path.join(start_dir, "__init__.py"))

        loader = unittest.TestLoader()

        new_loader = load_tests(
            loader, unittest.suite.TestSuite(), "test_fixtures.py")

        self.assertIsInstance(new_loader, testresources.OptimisingTestSuite)

        actual_tests = unittest.TestSuite(
            testscenarios.generate_scenarios(
                loader.discover(start_dir, pattern="test_fixtures.py"))
        )

        self.assertEqual(
            new_loader.countTestCases(), actual_tests.countTestCases()
        )


class TestWScenarios(unittest.TestCase):
    """a 'do nothing' test suite.

    Should generate exactly four tests when testscenarios is used.

    """

    def test_one(self):
        pass

    def test_two(self):
        pass

    scenarios = [
        ('scenario1', dict(scenario='scenario 1')),
        ('scenario2', dict(scenario='scenario 2'))
    ]
