# Copyright 2012 OpenStack Foundation
#
# 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 uuid

from keystone.common import manager
from keystone.common import provider_api
from keystone.tests import unit


class TestProviderAPIRegistry(unit.BaseTestCase):
    def setUp(self):
        super().setUp()
        provider_api.ProviderAPIs._clear_registry_instances()
        self.addCleanup(provider_api.ProviderAPIs._clear_registry_instances)

    def _create_manager_instance(self, provides_api=None):
        provides_api = provides_api or f'{uuid.uuid4().hex}_api'

        class TestManager(manager.Manager):
            _provides_api = provides_api
            driver_namespace = '_TEST_NOTHING'

            def do_something(self):
                return provides_api

        return TestManager(driver_name=None)

    def test_deferred_gettr(self):
        api_name = f'{uuid.uuid4().hex}_api'

        class TestClass:
            descriptor = provider_api.ProviderAPIs.deferred_provider_lookup(
                api=api_name, method='do_something'
            )

        test_instance = TestClass()
        # Accessing the descriptor will raise the known "attribute" error
        self.assertRaises(AttributeError, getattr, test_instance, 'descriptor')
        self._create_manager_instance(provides_api=api_name)
        # once the provider has been instantiated, we can call the descriptor
        # which will return the method (callable) and we can check that the
        # return value is as expected.
        self.assertEqual(api_name, test_instance.descriptor())

    def test_registry_lock(self):
        provider_api.ProviderAPIs.lock_provider_registry()
        self.assertRaises(RuntimeError, self._create_manager_instance)

    def test_registry_duplicate(self):
        test_manager = self._create_manager_instance()
        self.assertRaises(
            provider_api.DuplicateProviderError,
            self._create_manager_instance,
            provides_api=test_manager._provides_api,
        )

    def test_provider_api_mixin(self):
        test_manager = self._create_manager_instance()

        class Testing(provider_api.ProviderAPIMixin):
            pass

        instance = Testing()
        self.assertIs(
            test_manager, getattr(instance, test_manager._provides_api)
        )

    def test_manager_api_reference(self):
        manager = self._create_manager_instance()
        second_manager = self._create_manager_instance()
        self.assertIs(
            second_manager, getattr(manager, second_manager._provides_api)
        )
        self.assertIs(manager, getattr(second_manager, manager._provides_api))
