from django.conf import settings
from django.contrib.auth import get_user_model
from django.contrib.auth.models import Group, Permission as DjangoPermission
from django.contrib.contenttypes.models import ContentType
from django.core.exceptions import MultipleObjectsReturned
from django.db.models import Q
from django.test import TestCase
from django.urls import reverse

import authority
from authority import permissions
from authority.models import Permission
from authority.exceptions import NotAModel, UnsavedModelInstance

# Load the form
from authority.forms import UserPermissionForm  # noqa


User = get_user_model()
FIXTURES = ["tests_custom.json"]
QUERY = Q(email="jezdez@github.com")


class UserPermission(permissions.BasePermission):
    checks = ("browse",)
    label = "user_permission"


authority.utils.register(User, UserPermission)


class GroupPermission(permissions.BasePermission):
    checks = ("browse",)
    label = "group_permission"


authority.utils.register(Group, GroupPermission)


class DjangoPermissionChecksTestCase(TestCase):
    """
    Django permission objects have certain methods that are always present,
    test those here.

    self.user will be given:
    - django permission add_user (test_add)
    - authority to delete_user which is him (test_delete)

    This permissions are given in the test case and not in the fixture, for
    later reference.
    """

    fixtures = FIXTURES

    def setUp(self):
        self.user = User.objects.get(QUERY)
        self.check = UserPermission(self.user)

    def test_no_permission(self):
        self.assertFalse(self.check.add_user())
        self.assertFalse(self.check.delete_user())
        self.assertFalse(self.check.delete_user(self.user))

    def test_add(self):
        # setup
        perm = DjangoPermission.objects.get(codename="add_user")
        self.user.user_permissions.add(perm)

        # test
        self.assertTrue(self.check.add_user())

    def test_delete(self):
        perm = Permission(
            user=self.user,
            content_object=self.user,
            codename="user_permission.delete_user",
            approved=True,
        )
        perm.save()

        # test
        self.assertFalse(self.check.delete_user())
        self.assertTrue(self.check.delete_user(self.user))


class AssignBehaviourTest(TestCase):
    """
    self.user will be given:
    - permission add_user (test_add),
    - permission delete_user for him (test_delete),
    - all existing codenames permissions: a/b/c/d (test_all),
    """

    fixtures = FIXTURES

    def setUp(self):
        self.user = User.objects.get(QUERY)
        self.group1, _ = Group.objects.get_or_create(name="Test Group 1")
        self.group2, _ = Group.objects.get_or_create(name="Test Group 2")
        self.group3, _ = Group.objects.get_or_create(name="Test Group 2")
        self.check = UserPermission(self.user)

    def test_add(self):
        result = self.check.assign(check="add_user")

        self.assertTrue(isinstance(result[0], DjangoPermission))
        self.assertTrue(self.check.add_user())

    def test_assign_to_group(self):
        result = UserPermission(group=self.group1).assign(
            check="delete_user", content_object=self.user
        )

        self.assertIsInstance(result, list)
        self.assertIsInstance(result[0], Permission)
        self.assertTrue(UserPermission(group=self.group1).delete_user(self.user))

    def test_assign_to_group_does_not_overwrite_other_group_permission(self):
        UserPermission(group=self.group1).assign(
            check="delete_user", content_object=self.user
        )
        UserPermission(group=self.group2).assign(
            check="delete_user", content_object=self.user
        )
        self.assertTrue(UserPermission(group=self.group2).delete_user(self.user))
        self.assertTrue(UserPermission(group=self.group1).delete_user(self.user))

    def test_assign_to_group_does_not_fail_when_two_group_perms_exist(self):
        for group in self.group1, self.group2:
            perm = Permission(
                group=group,
                content_object=self.user,
                codename="user_permission.delete_user",
                approved=True,
            )
            perm.save()

        try:
            UserPermission(group=self.group3).assign(
                check="delete_user", content_object=self.user
            )
        except MultipleObjectsReturned:
            self.fail("assign() should not have raised this exception")

    def test_delete(self):
        result = self.check.assign(content_object=self.user, check="delete_user",)

        self.assertTrue(isinstance(result[0], Permission))
        self.assertFalse(self.check.delete_user())
        self.assertTrue(self.check.delete_user(self.user))

    def test_all(self):
        result = self.check.assign(content_object=self.user)
        self.assertTrue(isinstance(result, list))
        self.assertTrue(self.check.browse_user(self.user))
        self.assertTrue(self.check.delete_user(self.user))
        self.assertTrue(self.check.add_user(self.user))
        self.assertTrue(self.check.change_user(self.user))


class GenericAssignBehaviourTest(TestCase):
    """
    self.user will be given:
    - permission add (test_add),
    - permission delete for him (test_delete),
    """

    fixtures = FIXTURES

    def setUp(self):
        self.user = User.objects.get(QUERY)
        self.check = UserPermission(self.user)

    def test_add(self):
        result = self.check.assign(check="add", generic=True)

        self.assertTrue(isinstance(result[0], DjangoPermission))
        self.assertTrue(self.check.add_user())

    def test_delete(self):
        result = self.check.assign(
            content_object=self.user, check="delete", generic=True,
        )

        self.assertTrue(isinstance(result[0], Permission))
        self.assertFalse(self.check.delete_user())
        self.assertTrue(self.check.delete_user(self.user))


class AssignExceptionsTest(TestCase):
    """
    Tests that exceptions are thrown if assign() was called with inconsistent
    arguments.
    """

    fixtures = FIXTURES

    def setUp(self):
        self.user = User.objects.get(QUERY)
        self.check = UserPermission(self.user)

    def test_unsaved_model(self):
        try:
            self.check.assign(content_object=User())
        except UnsavedModelInstance:
            return True
        self.fail()

    def test_not_model_content_object(self):
        try:
            self.check.assign(content_object="fail")
        except NotAModel:
            return True
        self.fail()


class SmartCachingTestCase(TestCase):
    """
    The base test case for all tests that have to do with smart caching.
    """

    fixtures = FIXTURES

    def setUp(self):
        # Create a user.
        self.user = User.objects.get(QUERY)

        # Create a group.
        self.group = Group.objects.create()
        self.group.user_set.add(self.user)

        # Make the checks
        self.user_check = UserPermission(user=self.user)
        self.group_check = GroupPermission(group=self.group)

        # Ensure we are using the smart cache.
        settings.AUTHORITY_USE_SMART_CACHE = True

    def tearDown(self):
        ContentType.objects.clear_cache()

    def _old_user_permission_check(self):
        # This is what the old, pre-cache system would check to see if a user
        # had a given permission.
        return Permission.objects.user_permissions(
            self.user, "foo", self.user, approved=True, check_groups=True,
        )

    def _old_group_permission_check(self):
        # This is what the old, pre-cache system would check to see if a user
        # had a given permission.
        return Permission.objects.group_permissions(
            self.group, "foo", self.group, approved=True,
        )


class PerformanceTest(SmartCachingTestCase):
    """
    Tests that permission are actually cached and that the number of queries
    stays constant.
    """

    def test_has_user_perms(self):
        # Show that when calling has_user_perms multiple times no additional
        # queries are done.

        # Make sure the has_user_perms check does not get short-circuited.
        assert not self.user.is_superuser
        assert self.user.is_active

        # Regardless of how many times has_user_perms is called, the number of
        # queries is the same.
        # Content type and permissions (2 queries)
        with self.assertNumQueries(3):
            for _ in range(5):
                # Need to assert it so the query actually gets executed.
                assert not self.user_check.has_user_perms(
                    "foo", self.user, True, False,
                )

    def test_group_has_perms(self):
        with self.assertNumQueries(2):
            for _ in range(5):
                assert not self.group_check.has_group_perms("foo", self.group, True,)

    def test_has_user_perms_check_group(self):
        # Regardless of the number groups permissions, it should only take one
        # query to check both users and groups.
        # Content type and permissions (2 queries)
        with self.assertNumQueries(3):
            self.user_check.has_user_perms(
                "foo", self.user, approved=True, check_groups=True,
            )

    def test_invalidate_user_permissions_cache(self):
        # Show that calling invalidate_permissions_cache will cause extra
        # queries.
        # For each time invalidate_permissions_cache gets called, you
        # will need to do one query to get content type and one to get
        # the permissions.
        with self.assertNumQueries(6):
            for _ in range(5):
                assert not self.user_check.has_user_perms(
                    "foo", self.user, True, False,
                )

            # Invalidate the cache to show that a query will be generated when
            # checking perms again.
            self.user_check.invalidate_permissions_cache()
            ContentType.objects.clear_cache()

            # One query to re generate the cache.
            for _ in range(5):
                assert not self.user_check.has_user_perms(
                    "foo", self.user, True, False,
                )

    def test_invalidate_group_permissions_cache(self):
        # Show that calling invalidate_permissions_cache will cause extra
        # queries.
        # For each time invalidate_permissions_cache gets called, you
        # will need to do one query to get content type and one to get
        with self.assertNumQueries(4):
            for _ in range(5):
                assert not self.group_check.has_group_perms("foo", self.group, True,)

            # Invalidate the cache to show that a query will be generated when
            # checking perms again.
            self.group_check.invalidate_permissions_cache()
            ContentType.objects.clear_cache()

            # One query to re generate the cache.
            for _ in range(5):
                assert not self.group_check.has_group_perms("foo", self.group, True,)

    def test_has_user_perms_check_group_multiple(self):
        # Create a permission with just a group.
        Permission.objects.create(
            content_type=Permission.objects.get_content_type(User),
            object_id=self.user.pk,
            codename="foo",
            group=self.group,
            approved=True,
        )
        # By creating the Permission objects the Content type cache
        # gets created.

        # Check the number of queries.
        with self.assertNumQueries(2):
            assert self.user_check.has_user_perms("foo", self.user, True, True)

        # Create a second group.
        new_group = Group.objects.create(name="new_group")
        new_group.user_set.add(self.user)

        # Create a permission object for it.
        Permission.objects.create(
            content_type=Permission.objects.get_content_type(User),
            object_id=self.user.pk,
            codename="foo",
            group=new_group,
            approved=True,
        )

        self.user_check.invalidate_permissions_cache()

        # Make sure it is the same number of queries.
        with self.assertNumQueries(2):
            assert self.user_check.has_user_perms("foo", self.user, True, True)


class GroupPermissionCacheTestCase(SmartCachingTestCase):
    """
    Tests that peg expected behaviour
    """

    def test_has_user_perms_with_groups(self):
        perms = self._old_user_permission_check()
        self.assertEqual([], list(perms))

        # Use the new cached user perms to show that the user does not have the
        # perms.
        can_foo_with_group = self.user_check.has_user_perms(
            "foo", self.user, approved=True, check_groups=True,
        )
        self.assertFalse(can_foo_with_group)

        # Create a permission with just that group.
        perm = Permission.objects.create(
            content_type=Permission.objects.get_content_type(User),
            object_id=self.user.pk,
            codename="foo",
            group=self.group,
            approved=True,
        )

        # Old permission check
        perms = self._old_user_permission_check()
        self.assertEqual([perm], list(perms))

        # Invalidate the cache.
        self.user_check.invalidate_permissions_cache()
        can_foo_with_group = self.user_check.has_user_perms(
            "foo", self.user, approved=True, check_groups=True,
        )
        self.assertTrue(can_foo_with_group)

    def test_has_group_perms_no_user(self):
        # Make sure calling has_user_perms on a permission that does not have a
        # user does not throw any errors.
        can_foo_with_group = self.group_check.has_group_perms(
            "foo", self.user, approved=True,
        )
        self.assertFalse(can_foo_with_group)

        perms = self._old_group_permission_check()
        self.assertEqual([], list(perms))

        # Create a permission with just that group.
        perm = Permission.objects.create(
            content_type=Permission.objects.get_content_type(Group),
            object_id=self.group.pk,
            codename="foo",
            group=self.group,
            approved=True,
        )

        # Old permission check
        perms = self._old_group_permission_check()
        self.assertEqual([perm], list(perms))

        # Invalidate the cache.
        self.group_check.invalidate_permissions_cache()

        can_foo_with_group = self.group_check.has_group_perms(
            "foo", self.group, approved=True,
        )
        self.assertTrue(can_foo_with_group)


class AddPermissionTestCase(TestCase):
    def test_add_permission_permission_denied_is_403(self):
        user = get_user_model().objects.create(username="foo", email="foo@example.com",)
        user.set_password("pw")
        user.save()

        assert self.client.login(username="foo@example.com", password="pw")
        url = reverse(
            "authority-add-permission-request",
            kwargs={"app_label": "foo", "module_name": "Bar", "pk": 1,},
        )
        r = self.client.get(url)
        self.assertEqual(r.status_code, 403)