from __future__ import unicode_literals

import base64
import unittest
import warnings

import django
from django.contrib.auth.models import AnonymousUser, Group, Permission, User
from django.db import models
from django.test import TestCase
from django.urls import ResolverMatch

from rest_framework import (
    HTTP_HEADER_ENCODING, authentication, generics, permissions, serializers,
    status, views
)
from rest_framework.compat import is_guardian_installed
from rest_framework.filters import DjangoObjectPermissionsFilter
from rest_framework.routers import DefaultRouter
from rest_framework.test import APIRequestFactory
from tests.models import BasicModel

factory = APIRequestFactory()


class BasicSerializer(serializers.ModelSerializer):
    class Meta:
        model = BasicModel
        fields = '__all__'


class RootView(generics.ListCreateAPIView):
    queryset = BasicModel.objects.all()
    serializer_class = BasicSerializer
    authentication_classes = [authentication.BasicAuthentication]
    permission_classes = [permissions.DjangoModelPermissions]


class InstanceView(generics.RetrieveUpdateDestroyAPIView):
    queryset = BasicModel.objects.all()
    serializer_class = BasicSerializer
    authentication_classes = [authentication.BasicAuthentication]
    permission_classes = [permissions.DjangoModelPermissions]


class GetQuerySetListView(generics.ListCreateAPIView):
    serializer_class = BasicSerializer
    authentication_classes = [authentication.BasicAuthentication]
    permission_classes = [permissions.DjangoModelPermissions]

    def get_queryset(self):
        return BasicModel.objects.all()


class EmptyListView(generics.ListCreateAPIView):
    queryset = BasicModel.objects.none()
    serializer_class = BasicSerializer
    authentication_classes = [authentication.BasicAuthentication]
    permission_classes = [permissions.DjangoModelPermissions]


root_view = RootView.as_view()
api_root_view = DefaultRouter().get_api_root_view()
instance_view = InstanceView.as_view()
get_queryset_list_view = GetQuerySetListView.as_view()
empty_list_view = EmptyListView.as_view()


def basic_auth_header(username, password):
    credentials = ('%s:%s' % (username, password))
    base64_credentials = base64.b64encode(credentials.encode(HTTP_HEADER_ENCODING)).decode(HTTP_HEADER_ENCODING)
    return 'Basic %s' % base64_credentials


class ModelPermissionsIntegrationTests(TestCase):
    def setUp(self):
        User.objects.create_user('disallowed', 'disallowed@example.com', 'password')
        user = User.objects.create_user('permitted', 'permitted@example.com', 'password')
        user.user_permissions.set([
            Permission.objects.get(codename='add_basicmodel'),
            Permission.objects.get(codename='change_basicmodel'),
            Permission.objects.get(codename='delete_basicmodel')
        ])

        user = User.objects.create_user('updateonly', 'updateonly@example.com', 'password')
        user.user_permissions.set([
            Permission.objects.get(codename='change_basicmodel'),
        ])

        self.permitted_credentials = basic_auth_header('permitted', 'password')
        self.disallowed_credentials = basic_auth_header('disallowed', 'password')
        self.updateonly_credentials = basic_auth_header('updateonly', 'password')

        BasicModel(text='foo').save()

    def test_has_create_permissions(self):
        request = factory.post('/', {'text': 'foobar'}, format='json',
                               HTTP_AUTHORIZATION=self.permitted_credentials)
        response = root_view(request, pk=1)
        self.assertEqual(response.status_code, status.HTTP_201_CREATED)

    def test_api_root_view_discard_default_django_model_permission(self):
        """
        We check that DEFAULT_PERMISSION_CLASSES can
        apply to APIRoot view. More specifically we check expected behavior of
        ``_ignore_model_permissions`` attribute support.
        """
        request = factory.get('/', format='json',
                              HTTP_AUTHORIZATION=self.permitted_credentials)
        request.resolver_match = ResolverMatch('get', (), {})
        response = api_root_view(request)
        self.assertEqual(response.status_code, status.HTTP_200_OK)

    def test_get_queryset_has_create_permissions(self):
        request = factory.post('/', {'text': 'foobar'}, format='json',
                               HTTP_AUTHORIZATION=self.permitted_credentials)
        response = get_queryset_list_view(request, pk=1)
        self.assertEqual(response.status_code, status.HTTP_201_CREATED)

    def test_has_put_permissions(self):
        request = factory.put('/1', {'text': 'foobar'}, format='json',
                              HTTP_AUTHORIZATION=self.permitted_credentials)
        response = instance_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)

    def test_has_delete_permissions(self):
        request = factory.delete('/1', HTTP_AUTHORIZATION=self.permitted_credentials)
        response = instance_view(request, pk=1)
        self.assertEqual(response.status_code, status.HTTP_204_NO_CONTENT)

    def test_does_not_have_create_permissions(self):
        request = factory.post('/', {'text': 'foobar'}, format='json',
                               HTTP_AUTHORIZATION=self.disallowed_credentials)
        response = root_view(request, pk=1)
        self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)

    def test_does_not_have_put_permissions(self):
        request = factory.put('/1', {'text': 'foobar'}, format='json',
                              HTTP_AUTHORIZATION=self.disallowed_credentials)
        response = instance_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)

    def test_does_not_have_delete_permissions(self):
        request = factory.delete('/1', HTTP_AUTHORIZATION=self.disallowed_credentials)
        response = instance_view(request, pk=1)
        self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)

    def test_options_permitted(self):
        request = factory.options(
            '/',
            HTTP_AUTHORIZATION=self.permitted_credentials
        )
        response = root_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertIn('actions', response.data)
        self.assertEqual(list(response.data['actions']), ['POST'])

        request = factory.options(
            '/1',
            HTTP_AUTHORIZATION=self.permitted_credentials
        )
        response = instance_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertIn('actions', response.data)
        self.assertEqual(list(response.data['actions']), ['PUT'])

    def test_options_disallowed(self):
        request = factory.options(
            '/',
            HTTP_AUTHORIZATION=self.disallowed_credentials
        )
        response = root_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertNotIn('actions', response.data)

        request = factory.options(
            '/1',
            HTTP_AUTHORIZATION=self.disallowed_credentials
        )
        response = instance_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertNotIn('actions', response.data)

    def test_options_updateonly(self):
        request = factory.options(
            '/',
            HTTP_AUTHORIZATION=self.updateonly_credentials
        )
        response = root_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertNotIn('actions', response.data)

        request = factory.options(
            '/1',
            HTTP_AUTHORIZATION=self.updateonly_credentials
        )
        response = instance_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertIn('actions', response.data)
        self.assertEqual(list(response.data['actions']), ['PUT'])

    def test_empty_view_does_not_assert(self):
        request = factory.get('/1', HTTP_AUTHORIZATION=self.permitted_credentials)
        response = empty_list_view(request, pk=1)
        self.assertEqual(response.status_code, status.HTTP_200_OK)

    def test_calling_method_not_allowed(self):
        request = factory.generic('METHOD_NOT_ALLOWED', '/', HTTP_AUTHORIZATION=self.permitted_credentials)
        response = root_view(request)
        self.assertEqual(response.status_code, status.HTTP_405_METHOD_NOT_ALLOWED)

        request = factory.generic('METHOD_NOT_ALLOWED', '/1', HTTP_AUTHORIZATION=self.permitted_credentials)
        response = instance_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_405_METHOD_NOT_ALLOWED)

    def test_check_auth_before_queryset_call(self):
        class View(RootView):
            def get_queryset(_):
                self.fail('should not reach due to auth check')
        view = View.as_view()

        request = factory.get('/', HTTP_AUTHORIZATION='')
        response = view(request)
        self.assertEqual(response.status_code, status.HTTP_401_UNAUTHORIZED)

    def test_queryset_assertions(self):
        class View(views.APIView):
            authentication_classes = [authentication.BasicAuthentication]
            permission_classes = [permissions.DjangoModelPermissions]
        view = View.as_view()

        request = factory.get('/', HTTP_AUTHORIZATION=self.permitted_credentials)
        msg = 'Cannot apply DjangoModelPermissions on a view that does not set `.queryset` or have a `.get_queryset()` method.'
        with self.assertRaisesMessage(AssertionError, msg):
            view(request)

        # Faulty `get_queryset()` methods should trigger the above "view does not have a queryset" assertion.
        class View(RootView):
            def get_queryset(self):
                return None
        view = View.as_view()

        request = factory.get('/', HTTP_AUTHORIZATION=self.permitted_credentials)
        with self.assertRaisesMessage(AssertionError, 'View.get_queryset() returned None'):
            view(request)


class BasicPermModel(models.Model):
    text = models.CharField(max_length=100)

    class Meta:
        app_label = 'tests'

        if django.VERSION < (2, 1):
            permissions = (
                ('view_basicpermmodel', 'Can view basic perm model'),
                # add, change, delete built in to django
            )


class BasicPermSerializer(serializers.ModelSerializer):
    class Meta:
        model = BasicPermModel
        fields = '__all__'


# Custom object-level permission, that includes 'view' permissions
class ViewObjectPermissions(permissions.DjangoObjectPermissions):
    perms_map = {
        'GET': ['%(app_label)s.view_%(model_name)s'],
        'OPTIONS': ['%(app_label)s.view_%(model_name)s'],
        'HEAD': ['%(app_label)s.view_%(model_name)s'],
        'POST': ['%(app_label)s.add_%(model_name)s'],
        'PUT': ['%(app_label)s.change_%(model_name)s'],
        'PATCH': ['%(app_label)s.change_%(model_name)s'],
        'DELETE': ['%(app_label)s.delete_%(model_name)s'],
    }


class ObjectPermissionInstanceView(generics.RetrieveUpdateDestroyAPIView):
    queryset = BasicPermModel.objects.all()
    serializer_class = BasicPermSerializer
    authentication_classes = [authentication.BasicAuthentication]
    permission_classes = [ViewObjectPermissions]


object_permissions_view = ObjectPermissionInstanceView.as_view()


class ObjectPermissionListView(generics.ListAPIView):
    queryset = BasicPermModel.objects.all()
    serializer_class = BasicPermSerializer
    authentication_classes = [authentication.BasicAuthentication]
    permission_classes = [ViewObjectPermissions]


object_permissions_list_view = ObjectPermissionListView.as_view()


class GetQuerysetObjectPermissionInstanceView(generics.RetrieveUpdateDestroyAPIView):
    serializer_class = BasicPermSerializer
    authentication_classes = [authentication.BasicAuthentication]
    permission_classes = [ViewObjectPermissions]

    def get_queryset(self):
        return BasicPermModel.objects.all()


get_queryset_object_permissions_view = GetQuerysetObjectPermissionInstanceView.as_view()


@unittest.skipUnless(is_guardian_installed(), 'django-guardian not installed')
class ObjectPermissionsIntegrationTests(TestCase):
    """
    Integration tests for the object level permissions API.
    """
    def setUp(self):
        from guardian.shortcuts import assign_perm

        # create users
        create = User.objects.create_user
        users = {
            'fullaccess': create('fullaccess', 'fullaccess@example.com', 'password'),
            'readonly': create('readonly', 'readonly@example.com', 'password'),
            'writeonly': create('writeonly', 'writeonly@example.com', 'password'),
            'deleteonly': create('deleteonly', 'deleteonly@example.com', 'password'),
        }

        # give everyone model level permissions, as we are not testing those
        everyone = Group.objects.create(name='everyone')
        model_name = BasicPermModel._meta.model_name
        app_label = BasicPermModel._meta.app_label
        f = '{0}_{1}'.format
        perms = {
            'view': f('view', model_name),
            'change': f('change', model_name),
            'delete': f('delete', model_name)
        }
        for perm in perms.values():
            perm = '{0}.{1}'.format(app_label, perm)
            assign_perm(perm, everyone)
        everyone.user_set.add(*users.values())

        # appropriate object level permissions
        readers = Group.objects.create(name='readers')
        writers = Group.objects.create(name='writers')
        deleters = Group.objects.create(name='deleters')

        model = BasicPermModel.objects.create(text='foo')

        assign_perm(perms['view'], readers, model)
        assign_perm(perms['change'], writers, model)
        assign_perm(perms['delete'], deleters, model)

        readers.user_set.add(users['fullaccess'], users['readonly'])
        writers.user_set.add(users['fullaccess'], users['writeonly'])
        deleters.user_set.add(users['fullaccess'], users['deleteonly'])

        self.credentials = {}
        for user in users.values():
            self.credentials[user.username] = basic_auth_header(user.username, 'password')

    # Delete
    def test_can_delete_permissions(self):
        request = factory.delete('/1', HTTP_AUTHORIZATION=self.credentials['deleteonly'])
        response = object_permissions_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_204_NO_CONTENT)

    def test_cannot_delete_permissions(self):
        request = factory.delete('/1', HTTP_AUTHORIZATION=self.credentials['readonly'])
        response = object_permissions_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)

    # Update
    def test_can_update_permissions(self):
        request = factory.patch(
            '/1', {'text': 'foobar'}, format='json',
            HTTP_AUTHORIZATION=self.credentials['writeonly']
        )
        response = object_permissions_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.data.get('text'), 'foobar')

    def test_cannot_update_permissions(self):
        request = factory.patch(
            '/1', {'text': 'foobar'}, format='json',
            HTTP_AUTHORIZATION=self.credentials['deleteonly']
        )
        response = object_permissions_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)

    def test_cannot_update_permissions_non_existing(self):
        request = factory.patch(
            '/999', {'text': 'foobar'}, format='json',
            HTTP_AUTHORIZATION=self.credentials['deleteonly']
        )
        response = object_permissions_view(request, pk='999')
        self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)

    # Read
    def test_can_read_permissions(self):
        request = factory.get('/1', HTTP_AUTHORIZATION=self.credentials['readonly'])
        response = object_permissions_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)

    def test_cannot_read_permissions(self):
        request = factory.get('/1', HTTP_AUTHORIZATION=self.credentials['writeonly'])
        response = object_permissions_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_404_NOT_FOUND)

    def test_can_read_get_queryset_permissions(self):
        """
        same as ``test_can_read_permissions`` but with a view
        that rely on ``.get_queryset()`` instead of ``.queryset``.
        """
        request = factory.get('/1', HTTP_AUTHORIZATION=self.credentials['readonly'])
        response = get_queryset_object_permissions_view(request, pk='1')
        self.assertEqual(response.status_code, status.HTTP_200_OK)

    # Read list
    def test_django_object_permissions_filter_deprecated(self):
        with warnings.catch_warnings(record=True) as w:
            warnings.simplefilter("always")
            DjangoObjectPermissionsFilter()

        message = ("`DjangoObjectPermissionsFilter` has been deprecated and moved "
                   "to the 3rd-party django-rest-framework-guardian package.")
        self.assertEqual(len(w), 1)
        self.assertIs(w[-1].category, DeprecationWarning)
        self.assertEqual(str(w[-1].message), message)

    def test_can_read_list_permissions(self):
        request = factory.get('/', HTTP_AUTHORIZATION=self.credentials['readonly'])
        object_permissions_list_view.cls.filter_backends = (DjangoObjectPermissionsFilter,)
        # TODO: remove in version 3.10
        with warnings.catch_warnings(record=True):
            warnings.simplefilter("always")
            response = object_permissions_list_view(request)
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertEqual(response.data[0].get('id'), 1)

    def test_cannot_read_list_permissions(self):
        request = factory.get('/', HTTP_AUTHORIZATION=self.credentials['writeonly'])
        object_permissions_list_view.cls.filter_backends = (DjangoObjectPermissionsFilter,)
        # TODO: remove in version 3.10
        with warnings.catch_warnings(record=True):
            warnings.simplefilter("always")
            response = object_permissions_list_view(request)
        self.assertEqual(response.status_code, status.HTTP_200_OK)
        self.assertListEqual(response.data, [])

    def test_cannot_method_not_allowed(self):
        request = factory.generic('METHOD_NOT_ALLOWED', '/', HTTP_AUTHORIZATION=self.credentials['readonly'])
        response = object_permissions_list_view(request)
        self.assertEqual(response.status_code, status.HTTP_405_METHOD_NOT_ALLOWED)


class BasicPerm(permissions.BasePermission):
    def has_permission(self, request, view):
        return False


class BasicPermWithDetail(permissions.BasePermission):
    message = 'Custom: You cannot access this resource'

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


class BasicObjectPerm(permissions.BasePermission):
    def has_object_permission(self, request, view, obj):
        return False


class BasicObjectPermWithDetail(permissions.BasePermission):
    message = 'Custom: You cannot access this resource'

    def has_object_permission(self, request, view, obj):
        return False


class PermissionInstanceView(generics.RetrieveUpdateDestroyAPIView):
    queryset = BasicModel.objects.all()
    serializer_class = BasicSerializer


class DeniedView(PermissionInstanceView):
    permission_classes = (BasicPerm,)


class DeniedViewWithDetail(PermissionInstanceView):
    permission_classes = (BasicPermWithDetail,)


class DeniedObjectView(PermissionInstanceView):
    permission_classes = (BasicObjectPerm,)


class DeniedObjectViewWithDetail(PermissionInstanceView):
    permission_classes = (BasicObjectPermWithDetail,)


denied_view = DeniedView.as_view()

denied_view_with_detail = DeniedViewWithDetail.as_view()

denied_object_view = DeniedObjectView.as_view()

denied_object_view_with_detail = DeniedObjectViewWithDetail.as_view()


class CustomPermissionsTests(TestCase):
    def setUp(self):
        BasicModel(text='foo').save()
        User.objects.create_user('username', 'username@example.com', 'password')
        credentials = basic_auth_header('username', 'password')
        self.request = factory.get('/1', format='json', HTTP_AUTHORIZATION=credentials)
        self.custom_message = 'Custom: You cannot access this resource'

    def test_permission_denied(self):
            response = denied_view(self.request, pk=1)
            detail = response.data.get('detail')
            self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
            self.assertNotEqual(detail, self.custom_message)

    def test_permission_denied_with_custom_detail(self):
            response = denied_view_with_detail(self.request, pk=1)
            detail = response.data.get('detail')
            self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
            self.assertEqual(detail, self.custom_message)

    def test_permission_denied_for_object(self):
            response = denied_object_view(self.request, pk=1)
            detail = response.data.get('detail')
            self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
            self.assertNotEqual(detail, self.custom_message)

    def test_permission_denied_for_object_with_custom_detail(self):
            response = denied_object_view_with_detail(self.request, pk=1)
            detail = response.data.get('detail')
            self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
            self.assertEqual(detail, self.custom_message)


class PermissionsCompositionTests(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
        )
        self.client.login(username=self.username, password=self.password)

    def test_and_false(self):
        request = factory.get('/1', format='json')
        request.user = AnonymousUser()
        composed_perm = permissions.IsAuthenticated & permissions.AllowAny
        assert composed_perm().has_permission(request, None) is False

    def test_and_true(self):
        request = factory.get('/1', format='json')
        request.user = self.user
        composed_perm = permissions.IsAuthenticated & permissions.AllowAny
        assert composed_perm().has_permission(request, None) is True

    def test_or_false(self):
        request = factory.get('/1', format='json')
        request.user = AnonymousUser()
        composed_perm = permissions.IsAuthenticated | permissions.AllowAny
        assert composed_perm().has_permission(request, None) is True

    def test_or_true(self):
        request = factory.get('/1', format='json')
        request.user = self.user
        composed_perm = permissions.IsAuthenticated | permissions.AllowAny
        assert composed_perm().has_permission(request, None) is True

    def test_several_levels(self):
        request = factory.get('/1', format='json')
        request.user = self.user
        composed_perm = (
            permissions.IsAuthenticated &
            permissions.IsAuthenticated &
            permissions.IsAuthenticated &
            permissions.IsAuthenticated
        )
        assert composed_perm().has_permission(request, None) is True

    def test_several_levels_and_precedence(self):
        request = factory.get('/1', format='json')
        request.user = self.user
        composed_perm = (
            permissions.IsAuthenticated &
            permissions.IsAuthenticated |
            permissions.IsAuthenticated &
            permissions.IsAuthenticated
        )
        assert composed_perm().has_permission(request, None) is True