"""
Tests for validate Internationalization and XBlock i18n service.
"""
import gettext
from unittest import mock

from django.utils import translation

from django.utils.translation import get_language
from xblock.core import XBlock
from xmodule.modulestore.django import XBlockI18nService
from xmodule.modulestore.tests.django_utils import TEST_DATA_SPLIT_MODULESTORE, ModuleStoreTestCase
from xmodule.modulestore.tests.factories import CourseFactory, BlockFactory
from xmodule.tests.test_export import PureXBlock

from cms.djangoapps.contentstore.views.preview import _prepare_runtime_for_preview


class FakeTranslations(XBlockI18nService):
    """A test GNUTranslations class that takes a map of msg -> translations."""

    def __init__(self, translations):  # pylint: disable=super-init-not-called
        self.translations = translations

    def ugettext(self, msgid):
        """
        Mock override for ugettext translation operation
        """
        return self.translations.get(msgid, msgid)

    gettext = ugettext

    @staticmethod
    def translator(locales_map):  # pylint: disable=method-hidden
        """Build mock translator for the given locales.
        Returns a mock gettext.translation function that uses
        individual TestTranslations to translate in the given locales.
        :param locales_map: A map from locale name to a translations map.
                            {
                             'es': {'Hi': 'Hola', 'Bye': 'Adios'},
                             'zh': {'Hi': 'Ni Hao', 'Bye': 'Zaijian'}
                            }
        """
        def _translation(domain, localedir=None, languages=None):  # pylint: disable=unused-argument
            """
            return gettext.translation for given language
            """
            if languages:
                language = languages[0]
                if language in locales_map:
                    return FakeTranslations(locales_map[language])
            return gettext.NullTranslations()
        return _translation


class TestXBlockI18nService(ModuleStoreTestCase):
    """ Test XBlockI18nService """
    MODULESTORE = TEST_DATA_SPLIT_MODULESTORE

    @XBlock.register_temp_plugin(PureXBlock, 'pure')
    def setUp(self):
        """ Setting up tests """
        super().setUp()
        self.test_language = 'dummy language'
        self.request = mock.Mock()
        self.course = CourseFactory.create()
        self.block = BlockFactory(category="pure", parent=self.course)
        _prepare_runtime_for_preview(self.request, self.block)
        self.addCleanup(translation.deactivate)

    def get_block_i18n_service(self, block):
        """
        return the block i18n service.
        """
        i18n_service = self.block.runtime.service(block, 'i18n')
        self.assertIsNotNone(i18n_service)
        self.assertIsInstance(i18n_service, XBlockI18nService)
        return i18n_service

    def test_django_service_translation_works(self):
        """
        Test django translation service works fine.
        """

        class wrap_ugettext_with_xyz:  # pylint: disable=invalid-name
            """
            A context manager function that just adds 'XYZ ' to the front
            of all strings of the module ugettext function.
            """

            def __init__(self, module):
                self.module = module
                self.old_ugettext = module.gettext

            def __enter__(self):
                def new_ugettext(*args, **kwargs):
                    """ custom function """
                    output = self.old_ugettext(*args, **kwargs)
                    return "XYZ " + output
                self.module.ugettext = new_ugettext
                self.module.gettext = new_ugettext

            def __exit__(self, _type, _value, _traceback):
                self.module.ugettext = self.old_ugettext
                self.module.gettext = self.old_ugettext

        i18n_service = self.get_block_i18n_service(self.block)

        # Activate french, so that if the fr files haven't been loaded, they will be loaded now.
        with translation.override("fr"):
            french_translation = translation.trans_real._active.value  # pylint: disable=protected-access

            # wrap the ugettext functions so that 'XYZ ' will prefix each translation
            with wrap_ugettext_with_xyz(french_translation):
                self.assertEqual(i18n_service.ugettext(self.test_language), 'XYZ dummy language')

            # Check that the old ugettext has been put back into place
            self.assertEqual(i18n_service.ugettext(self.test_language), 'dummy language')

    @mock.patch('django.utils.translation.gettext', mock.Mock(return_value='XYZ-TEST-LANGUAGE'))
    def test_django_translator_in_use_with_empty_block(self):
        """
        Test: Django default translator should in use if we have an empty block
        """
        i18n_service = XBlockI18nService(None)
        self.assertEqual(i18n_service.ugettext(self.test_language), 'XYZ-TEST-LANGUAGE')

    @mock.patch('django.utils.translation.gettext', mock.Mock(return_value='XYZ-TEST-LANGUAGE'))
    def test_message_catalog_translations(self):
        """
        Test: Message catalog from FakeTranslation should return required translations.
        """
        _translator = FakeTranslations.translator(
            {
                'es': {'Hello': 'es-hello-world'},
                'fr': {'Hello': 'fr-hello-world'},
            },
        )
        localedir = '/translations'
        translation.activate("es")
        with mock.patch('gettext.translation', return_value=_translator(domain='text', localedir=localedir,
                                                                        languages=[get_language()])):
            i18n_service = self.get_block_i18n_service(self.block)
            self.assertEqual(i18n_service.ugettext('Hello'), 'es-hello-world')

        translation.activate("ar")
        with mock.patch('gettext.translation', return_value=_translator(domain='text', localedir=localedir,
                                                                        languages=[get_language()])):
            i18n_service = self.get_block_i18n_service(self.block)
            self.assertEqual(i18n_service.gettext('Hello'), 'Hello')
            self.assertNotEqual(i18n_service.gettext('Hello'), 'fr-hello-world')
            self.assertNotEqual(i18n_service.gettext('Hello'), 'es-hello-world')

        translation.activate("fr")
        with mock.patch('gettext.translation', return_value=_translator(domain='text', localedir=localedir,
                                                                        languages=[get_language()])):
            i18n_service = self.get_block_i18n_service(self.block)
            self.assertEqual(i18n_service.ugettext('Hello'), 'fr-hello-world')

    def test_i18n_service_callable(self):
        """
        Test: i18n service should be callable in studio.
        """
        self.assertTrue(callable(self.block.runtime._services.get('i18n')))  # pylint: disable=protected-access