from django.template import TemplateDoesNotExist
from django.test import (
    Client, RequestFactory, SimpleTestCase, override_settings,
)
from django.utils.translation import override
from django.views.csrf import CSRF_FAILURE_TEMPLATE_NAME, csrf_failure


@override_settings(ROOT_URLCONF='view_tests.urls')
class CsrfViewTests(SimpleTestCase):

    def setUp(self):
        super().setUp()
        self.client = Client(enforce_csrf_checks=True)

    @override_settings(
        USE_I18N=True,
        MIDDLEWARE=[
            'django.middleware.locale.LocaleMiddleware',
            'django.middleware.common.CommonMiddleware',
            'django.middleware.csrf.CsrfViewMiddleware',
        ],
    )
    def test_translation(self):
        """An invalid request is rejected with a localized error message."""
        response = self.client.post('/')
        self.assertContains(response, 'Forbidden', status_code=403)
        self.assertContains(response, 'CSRF verification failed. Request aborted.', status_code=403)

        with self.settings(LANGUAGE_CODE='nl'), override('en-us'):
            response = self.client.post('/')
            self.assertContains(response, 'Verboden', status_code=403)
            self.assertContains(response, 'CSRF-verificatie mislukt. Verzoek afgebroken.', status_code=403)

    @override_settings(
        SECURE_PROXY_SSL_HEADER=('HTTP_X_FORWARDED_PROTO', 'https')
    )
    def test_no_referer(self):
        """
        Referer header is strictly checked for POST over HTTPS. Trigger the
        exception by sending an incorrect referer.
        """
        response = self.client.post('/', HTTP_X_FORWARDED_PROTO='https')
        self.assertContains(
            response,
            'You are seeing this message because this HTTPS site requires a '
            '“Referer header” to be sent by your Web browser, but '
            'none was sent.',
            status_code=403,
        )
        self.assertContains(
            response,
            'If you have configured your browser to disable “Referer” '
            'headers, please re-enable them, at least for this site, or for '
            'HTTPS connections, or for “same-origin” requests.',
            status_code=403,
        )
        self.assertContains(
            response,
            'If you are using the <meta name="referrer" '
            'content="no-referrer"> tag or including the '
            '“Referrer-Policy: no-referrer” header, please remove them.',
            status_code=403,
        )

    def test_no_cookies(self):
        """
        The CSRF cookie is checked for POST. Failure to send this cookie should
        provide a nice error message.
        """
        response = self.client.post('/')
        self.assertContains(
            response,
            'You are seeing this message because this site requires a CSRF '
            'cookie when submitting forms. This cookie is required for '
            'security reasons, to ensure that your browser is not being '
            'hijacked by third parties.',
            status_code=403,
        )

    @override_settings(TEMPLATES=[])
    def test_no_django_template_engine(self):
        """
        The CSRF view doesn't depend on the TEMPLATES configuration (#24388).
        """
        response = self.client.post('/')
        self.assertContains(response, 'Forbidden', status_code=403)

    @override_settings(TEMPLATES=[{
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'OPTIONS': {
            'loaders': [
                ('django.template.loaders.locmem.Loader', {
                    CSRF_FAILURE_TEMPLATE_NAME: 'Test template for CSRF failure'
                }),
            ],
        },
    }])
    def test_custom_template(self):
        """A custom CSRF_FAILURE_TEMPLATE_NAME is used."""
        response = self.client.post('/')
        self.assertContains(response, 'Test template for CSRF failure', status_code=403)

    def test_custom_template_does_not_exist(self):
        """An exception is raised if a nonexistent template is supplied."""
        factory = RequestFactory()
        request = factory.post('/')
        with self.assertRaises(TemplateDoesNotExist):
            csrf_failure(request, template_name='nonexistent.html')