# coding: utf-8

from __future__ import unicode_literals

import base64

import pytest
from django.conf import settings
from django.conf.urls import include, url
from django.contrib.auth.models import User
from django.db import models
from django.http import HttpResponse
from django.test import TestCase, override_settings
from django.utils import six

from rest_framework import (
    HTTP_HEADER_ENCODING, exceptions, permissions, renderers, status
)
from rest_framework.authentication import (
    BaseAuthentication, BasicAuthentication, RemoteUserAuthentication,
    SessionAuthentication, TokenAuthentication
)
from rest_framework.authtoken.models import Token
from rest_framework.authtoken.views import obtain_auth_token
from rest_framework.response import Response
from rest_framework.test import APIClient, APIRequestFactory
from rest_framework.views import APIView

factory = APIRequestFactory()


class CustomToken(models.Model):
    key = models.CharField(max_length=40, primary_key=True)
    user = models.OneToOneField(User, on_delete=models.CASCADE)


class CustomTokenAuthentication(TokenAuthentication):
    model = CustomToken


class CustomKeywordTokenAuthentication(TokenAuthentication):
    keyword = 'Bearer'


class MockView(APIView):
    permission_classes = (permissions.IsAuthenticated,)

    def get(self, request):
        return HttpResponse({'a': 1, 'b': 2, 'c': 3})

    def post(self, request):
        return HttpResponse({'a': 1, 'b': 2, 'c': 3})

    def put(self, request):
        return HttpResponse({'a': 1, 'b': 2, 'c': 3})


urlpatterns = [
    url(
        r'^session/$',
        MockView.as_view(authentication_classes=[SessionAuthentication])
    ),
    url(
        r'^basic/$',
        MockView.as_view(authentication_classes=[BasicAuthentication])
    ),
    url(
        r'^remote-user/$',
        MockView.as_view(authentication_classes=[RemoteUserAuthentication])
    ),
    url(
        r'^token/$',
        MockView.as_view(authentication_classes=[TokenAuthentication])
    ),
    url(
        r'^customtoken/$',
        MockView.as_view(authentication_classes=[CustomTokenAuthentication])
    ),
    url(
        r'^customkeywordtoken/$',
        MockView.as_view(
            authentication_classes=[CustomKeywordTokenAuthentication]
        )
    ),
    url(r'^auth-token/$', obtain_auth_token),
    url(r'^auth/', include('rest_framework.urls', namespace='rest_framework')),
]


@override_settings(ROOT_URLCONF='tests.test_authentication')
class BasicAuthTests(TestCase):
    """Basic authentication"""
    def setUp(self):
        self.csrf_client = APIClient(enforce_csrf_checks=True)
        self.username = 'john'
        self.email = 'lennon@thebeatles.com'
        self.password = 'password'
        self.user = User.objects.create_user(
            self.username, self.email, self.password
        )

    def test_post_form_passing_basic_auth(self):
        """Ensure POSTing json over basic auth with correct credentials passes and does not require CSRF"""
        credentials = ('%s:%s' % (self.username, self.password))
        base64_credentials = base64.b64encode(
            credentials.encode(HTTP_HEADER_ENCODING)
        ).decode(HTTP_HEADER_ENCODING)
        auth = 'Basic %s' % base64_credentials
        response = self.csrf_client.post(
            '/basic/',
            {'example': 'example'},
            HTTP_AUTHORIZATION=auth
        )
        assert response.status_code == status.HTTP_200_OK

    def test_post_json_passing_basic_auth(self):
        """Ensure POSTing form over basic auth with correct credentials passes and does not require CSRF"""
        credentials = ('%s:%s' % (self.username, self.password))
        base64_credentials = base64.b64encode(
            credentials.encode(HTTP_HEADER_ENCODING)
        ).decode(HTTP_HEADER_ENCODING)
        auth = 'Basic %s' % base64_credentials
        response = self.csrf_client.post(
            '/basic/',
            {'example': 'example'},
            format='json',
            HTTP_AUTHORIZATION=auth
        )
        assert response.status_code == status.HTTP_200_OK

    def test_regression_handle_bad_base64_basic_auth_header(self):
        """Ensure POSTing JSON over basic auth with incorrectly padded Base64 string is handled correctly"""
        # regression test for issue in 'rest_framework.authentication.BasicAuthentication.authenticate'
        # https://github.com/encode/django-rest-framework/issues/4089
        auth = 'Basic =a='
        response = self.csrf_client.post(
            '/basic/',
            {'example': 'example'},
            format='json',
            HTTP_AUTHORIZATION=auth
        )
        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_post_form_failing_basic_auth(self):
        """Ensure POSTing form over basic auth without correct credentials fails"""
        response = self.csrf_client.post('/basic/', {'example': 'example'})
        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_post_json_failing_basic_auth(self):
        """Ensure POSTing json over basic auth without correct credentials fails"""
        response = self.csrf_client.post(
            '/basic/',
            {'example': 'example'},
            format='json'
        )
        assert response.status_code == status.HTTP_401_UNAUTHORIZED
        assert response['WWW-Authenticate'] == 'Basic realm="api"'

    def test_fail_post_if_credentials_are_missing(self):
        response = self.csrf_client.post(
            '/basic/', {'example': 'example'}, HTTP_AUTHORIZATION='Basic ')
        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_fail_post_if_credentials_contain_spaces(self):
        response = self.csrf_client.post(
            '/basic/', {'example': 'example'},
            HTTP_AUTHORIZATION='Basic foo bar'
        )
        assert response.status_code == status.HTTP_401_UNAUTHORIZED


@override_settings(ROOT_URLCONF='tests.test_authentication')
class SessionAuthTests(TestCase):
    """User session authentication"""
    def setUp(self):
        self.csrf_client = APIClient(enforce_csrf_checks=True)
        self.non_csrf_client = APIClient(enforce_csrf_checks=False)
        self.username = 'john'
        self.email = 'lennon@thebeatles.com'
        self.password = 'password'
        self.user = User.objects.create_user(
            self.username, self.email, self.password
        )

    def tearDown(self):
        self.csrf_client.logout()

    def test_login_view_renders_on_get(self):
        """
        Ensure the login template renders for a basic GET.

        cf. [#1810](https://github.com/encode/django-rest-framework/pull/1810)
        """
        response = self.csrf_client.get('/auth/login/')
        content = response.content.decode('utf8')
        assert '<label for="id_username">Username:</label>' in content

    def test_post_form_session_auth_failing_csrf(self):
        """
        Ensure POSTing form over session authentication without CSRF token fails.
        """
        self.csrf_client.login(username=self.username, password=self.password)
        response = self.csrf_client.post('/session/', {'example': 'example'})
        assert response.status_code == status.HTTP_403_FORBIDDEN

    def test_post_form_session_auth_passing_csrf(self):
        """
        Ensure POSTing form over session authentication with CSRF token succeeds.
        Regression test for #6088
        """
        from django.middleware.csrf import _get_new_csrf_token

        self.csrf_client.login(username=self.username, password=self.password)

        # Set the csrf_token cookie so that CsrfViewMiddleware._get_token() works
        token = _get_new_csrf_token()
        self.csrf_client.cookies[settings.CSRF_COOKIE_NAME] = token

        # Post the token matching the cookie value
        response = self.csrf_client.post('/session/', {
            'example': 'example',
            'csrfmiddlewaretoken': token,
        })
        assert response.status_code == status.HTTP_200_OK

    def test_post_form_session_auth_passing(self):
        """
        Ensure POSTing form over session authentication with logged in
        user and CSRF token passes.
        """
        self.non_csrf_client.login(
            username=self.username, password=self.password
        )
        response = self.non_csrf_client.post(
            '/session/', {'example': 'example'}
        )
        assert response.status_code == status.HTTP_200_OK

    def test_put_form_session_auth_passing(self):
        """
        Ensure PUTting form over session authentication with
        logged in user and CSRF token passes.
        """
        self.non_csrf_client.login(
            username=self.username, password=self.password
        )
        response = self.non_csrf_client.put(
            '/session/', {'example': 'example'}
        )
        assert response.status_code == status.HTTP_200_OK

    def test_post_form_session_auth_failing(self):
        """
        Ensure POSTing form over session authentication without logged in user fails.
        """
        response = self.csrf_client.post('/session/', {'example': 'example'})
        assert response.status_code == status.HTTP_403_FORBIDDEN


class BaseTokenAuthTests(object):
    """Token authentication"""
    model = None
    path = None
    header_prefix = 'Token '

    def setUp(self):
        self.csrf_client = APIClient(enforce_csrf_checks=True)
        self.username = 'john'
        self.email = 'lennon@thebeatles.com'
        self.password = 'password'
        self.user = User.objects.create_user(
            self.username, self.email, self.password
        )

        self.key = 'abcd1234'
        self.token = self.model.objects.create(key=self.key, user=self.user)

    def test_post_form_passing_token_auth(self):
        """
        Ensure POSTing json over token auth with correct
        credentials passes and does not require CSRF
        """
        auth = self.header_prefix + self.key
        response = self.csrf_client.post(
            self.path, {'example': 'example'}, HTTP_AUTHORIZATION=auth
        )
        assert response.status_code == status.HTTP_200_OK

    def test_fail_authentication_if_user_is_not_active(self):
        user = User.objects.create_user('foo', 'bar', 'baz')
        user.is_active = False
        user.save()
        self.model.objects.create(key='foobar_token', user=user)
        response = self.csrf_client.post(
            self.path, {'example': 'example'},
            HTTP_AUTHORIZATION=self.header_prefix + 'foobar_token'
        )
        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_fail_post_form_passing_nonexistent_token_auth(self):
        # use a nonexistent token key
        auth = self.header_prefix + 'wxyz6789'
        response = self.csrf_client.post(
            self.path, {'example': 'example'}, HTTP_AUTHORIZATION=auth
        )
        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_fail_post_if_token_is_missing(self):
        response = self.csrf_client.post(
            self.path, {'example': 'example'},
            HTTP_AUTHORIZATION=self.header_prefix)
        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_fail_post_if_token_contains_spaces(self):
        response = self.csrf_client.post(
            self.path, {'example': 'example'},
            HTTP_AUTHORIZATION=self.header_prefix + 'foo bar'
        )
        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_fail_post_form_passing_invalid_token_auth(self):
        # add an 'invalid' unicode character
        auth = self.header_prefix + self.key + "¸"
        response = self.csrf_client.post(
            self.path, {'example': 'example'}, HTTP_AUTHORIZATION=auth
        )
        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_post_json_passing_token_auth(self):
        """
        Ensure POSTing form over token auth with correct
        credentials passes and does not require CSRF
        """
        auth = self.header_prefix + self.key
        response = self.csrf_client.post(
            self.path, {'example': 'example'},
            format='json', HTTP_AUTHORIZATION=auth
        )
        assert response.status_code == status.HTTP_200_OK

    def test_post_json_makes_one_db_query(self):
        """
        Ensure that authenticating a user using a
        token performs only one DB query
        """
        auth = self.header_prefix + self.key

        def func_to_test():
            return self.csrf_client.post(
                self.path, {'example': 'example'},
                format='json', HTTP_AUTHORIZATION=auth
            )

        self.assertNumQueries(1, func_to_test)

    def test_post_form_failing_token_auth(self):
        """
        Ensure POSTing form over token auth without correct credentials fails
        """
        response = self.csrf_client.post(self.path, {'example': 'example'})
        assert response.status_code == status.HTTP_401_UNAUTHORIZED

    def test_post_json_failing_token_auth(self):
        """
        Ensure POSTing json over token auth without correct credentials fails
        """
        response = self.csrf_client.post(
            self.path, {'example': 'example'}, format='json'
        )
        assert response.status_code == status.HTTP_401_UNAUTHORIZED


@override_settings(ROOT_URLCONF='tests.test_authentication')
class TokenAuthTests(BaseTokenAuthTests, TestCase):
    model = Token
    path = '/token/'

    def test_token_has_auto_assigned_key_if_none_provided(self):
        """Ensure creating a token with no key will auto-assign a key"""
        self.token.delete()
        token = self.model.objects.create(user=self.user)
        assert bool(token.key)

    def test_generate_key_returns_string(self):
        """Ensure generate_key returns a string"""
        token = self.model()
        key = token.generate_key()
        assert isinstance(key, six.string_types)

    def test_token_login_json(self):
        """Ensure token login view using JSON POST works."""
        client = APIClient(enforce_csrf_checks=True)
        response = client.post(
            '/auth-token/',
            {'username': self.username, 'password': self.password},
            format='json'
        )
        assert response.status_code == status.HTTP_200_OK
        assert response.data['token'] == self.key

    def test_token_login_json_bad_creds(self):
        """
        Ensure token login view using JSON POST fails if
        bad credentials are used
        """
        client = APIClient(enforce_csrf_checks=True)
        response = client.post(
            '/auth-token/',
            {'username': self.username, 'password': "badpass"},
            format='json'
        )
        assert response.status_code == 400

    def test_token_login_json_missing_fields(self):
        """Ensure token login view using JSON POST fails if missing fields."""
        client = APIClient(enforce_csrf_checks=True)
        response = client.post('/auth-token/',
                               {'username': self.username}, format='json')
        assert response.status_code == 400

    def test_token_login_form(self):
        """Ensure token login view using form POST works."""
        client = APIClient(enforce_csrf_checks=True)
        response = client.post(
            '/auth-token/',
            {'username': self.username, 'password': self.password}
        )
        assert response.status_code == status.HTTP_200_OK
        assert response.data['token'] == self.key


@override_settings(ROOT_URLCONF='tests.test_authentication')
class CustomTokenAuthTests(BaseTokenAuthTests, TestCase):
    model = CustomToken
    path = '/customtoken/'


@override_settings(ROOT_URLCONF='tests.test_authentication')
class CustomKeywordTokenAuthTests(BaseTokenAuthTests, TestCase):
    model = Token
    path = '/customkeywordtoken/'
    header_prefix = 'Bearer '


class IncorrectCredentialsTests(TestCase):
    def test_incorrect_credentials(self):
        """
        If a request contains bad authentication credentials, then
        authentication should run and error, even if no permissions
        are set on the view.
        """
        class IncorrectCredentialsAuth(BaseAuthentication):
            def authenticate(self, request):
                raise exceptions.AuthenticationFailed('Bad credentials')

        request = factory.get('/')
        view = MockView.as_view(
            authentication_classes=(IncorrectCredentialsAuth,),
            permission_classes=()
        )
        response = view(request)
        assert response.status_code == status.HTTP_403_FORBIDDEN
        assert response.data == {'detail': 'Bad credentials'}


class FailingAuthAccessedInRenderer(TestCase):
    def setUp(self):
        class AuthAccessingRenderer(renderers.BaseRenderer):
            media_type = 'text/plain'
            format = 'txt'

            def render(self, data, media_type=None, renderer_context=None):
                request = renderer_context['request']
                if request.user.is_authenticated:
                    return b'authenticated'
                return b'not authenticated'

        class FailingAuth(BaseAuthentication):
            def authenticate(self, request):
                raise exceptions.AuthenticationFailed('authentication failed')

        class ExampleView(APIView):
            authentication_classes = (FailingAuth,)
            renderer_classes = (AuthAccessingRenderer,)

            def get(self, request):
                return Response({'foo': 'bar'})

        self.view = ExampleView.as_view()

    def test_failing_auth_accessed_in_renderer(self):
        """
        When authentication fails the renderer should still be able to access
        `request.user` without raising an exception. Particularly relevant
        to HTML responses that might reasonably access `request.user`.
        """
        request = factory.get('/')
        response = self.view(request)
        content = response.render().content
        assert content == b'not authenticated'


class NoAuthenticationClassesTests(TestCase):
    def test_permission_message_with_no_authentication_classes(self):
        """
        An unauthenticated request made against a view that contains no
        `authentication_classes` but do contain `permissions_classes` the error
        code returned should be 403 with the exception's message.
        """

        class DummyPermission(permissions.BasePermission):
            message = 'Dummy permission message'

            def has_permission(self, request, view):
                return False

        request = factory.get('/')
        view = MockView.as_view(
            authentication_classes=(),
            permission_classes=(DummyPermission,),
        )
        response = view(request)
        assert response.status_code == status.HTTP_403_FORBIDDEN
        assert response.data == {'detail': 'Dummy permission message'}


class BasicAuthenticationUnitTests(TestCase):

    def test_base_authentication_abstract_method(self):
        with pytest.raises(NotImplementedError):
            BaseAuthentication().authenticate({})

    def test_basic_authentication_raises_error_if_user_not_found(self):
        auth = BasicAuthentication()
        with pytest.raises(exceptions.AuthenticationFailed):
            auth.authenticate_credentials('invalid id', 'invalid password')

    def test_basic_authentication_raises_error_if_user_not_active(self):
        from rest_framework import authentication

        class MockUser(object):
            is_active = False
        old_authenticate = authentication.authenticate
        authentication.authenticate = lambda **kwargs: MockUser()
        auth = authentication.BasicAuthentication()
        with pytest.raises(exceptions.AuthenticationFailed) as error:
            auth.authenticate_credentials('foo', 'bar')
        assert 'User inactive or deleted.' in str(error)
        authentication.authenticate = old_authenticate


@override_settings(ROOT_URLCONF='tests.test_authentication',
                   AUTHENTICATION_BACKENDS=('django.contrib.auth.backends.RemoteUserBackend',))
class RemoteUserAuthenticationUnitTests(TestCase):
    def setUp(self):
        self.username = 'john'
        self.email = 'lennon@thebeatles.com'
        self.password = 'password'
        self.user = User.objects.create_user(
            self.username, self.email, self.password
        )

    def test_remote_user_works(self):
        response = self.client.post('/remote-user/',
                                    REMOTE_USER=self.username)
        self.assertEqual(response.status_code, status.HTTP_200_OK)