from __future__ import unicode_literals

import datetime
import pickle
import unittest
import warnings

from django.db import models
from django.test import TestCase
from django.utils import six
from django.utils.encoding import force_text
from django.utils.version import get_version

from .models import Container, Event, Group, Happening, M2MModel


class PickleabilityTestCase(TestCase):
    def setUp(self):
        Happening.objects.create()  # make sure the defaults are working (#20158)

    def assert_pickles(self, qs):
        self.assertEqual(list(pickle.loads(pickle.dumps(qs))), list(qs))

    def test_related_field(self):
        g = Group.objects.create(name="Ponies Who Own Maybachs")
        self.assert_pickles(Event.objects.filter(group=g.id))

    def test_datetime_callable_default_all(self):
        self.assert_pickles(Happening.objects.all())

    def test_datetime_callable_default_filter(self):
        self.assert_pickles(Happening.objects.filter(when=datetime.datetime.now()))

    def test_string_as_default(self):
        self.assert_pickles(Happening.objects.filter(name="test"))

    def test_standalone_method_as_default(self):
        self.assert_pickles(Happening.objects.filter(number1=1))

    @unittest.skipIf(six.PY2, "Field doesn't exist on Python 2.")
    def test_staticmethod_as_default(self):
        self.assert_pickles(Happening.objects.filter(number2=1))

    def test_filter_reverse_fk(self):
        self.assert_pickles(Group.objects.filter(event=1))

    def test_doesnotexist_exception(self):
        # Ticket #17776
        original = Event.DoesNotExist("Doesn't exist")
        unpickled = pickle.loads(pickle.dumps(original))

        # Exceptions are not equal to equivalent instances of themselves, so
        # can't just use assertEqual(original, unpickled)
        self.assertEqual(original.__class__, unpickled.__class__)
        self.assertEqual(original.args, unpickled.args)

    def test_manager_pickle(self):
        pickle.loads(pickle.dumps(Happening.objects))

    def test_model_pickle(self):
        """
        Test that a model not defined on module level is pickleable.
        """
        original = Container.SomeModel(pk=1)
        dumped = pickle.dumps(original)
        reloaded = pickle.loads(dumped)
        self.assertEqual(original, reloaded)
        # Also, deferred dynamic model works
        Container.SomeModel.objects.create(somefield=1)
        original = Container.SomeModel.objects.defer('somefield')[0]
        dumped = pickle.dumps(original)
        reloaded = pickle.loads(dumped)
        self.assertEqual(original, reloaded)
        self.assertEqual(original.somefield, reloaded.somefield)

    def test_model_pickle_m2m(self):
        """
        Test intentionally the automatically created through model.
        """
        m1 = M2MModel.objects.create()
        g1 = Group.objects.create(name='foof')
        m1.groups.add(g1)
        m2m_through = M2MModel._meta.get_field('groups').remote_field.through
        original = m2m_through.objects.get()
        dumped = pickle.dumps(original)
        reloaded = pickle.loads(dumped)
        self.assertEqual(original, reloaded)

    def test_model_pickle_dynamic(self):
        class Meta:
            proxy = True
        dynclass = type(str("DynamicEventSubclass"), (Event, ),
                        {'Meta': Meta, '__module__': Event.__module__})
        original = dynclass(pk=1)
        dumped = pickle.dumps(original)
        reloaded = pickle.loads(dumped)
        self.assertEqual(original, reloaded)
        self.assertIs(reloaded.__class__, dynclass)

    def test_specialized_queryset(self):
        self.assert_pickles(Happening.objects.values('name'))
        self.assert_pickles(Happening.objects.values('name').dates('when', 'year'))
        # With related field (#14515)
        self.assert_pickles(
            Event.objects.select_related('group').order_by('title').values_list('title', 'group__name')
        )

    def test_pickle_prefetch_related_idempotence(self):
        g = Group.objects.create(name='foo')
        groups = Group.objects.prefetch_related('event_set')

        # First pickling
        groups = pickle.loads(pickle.dumps(groups))
        self.assertQuerysetEqual(groups, [g], lambda x: x)

        # Second pickling
        groups = pickle.loads(pickle.dumps(groups))
        self.assertQuerysetEqual(groups, [g], lambda x: x)

    def test_pickle_prefetch_related_with_m2m_and_objects_deletion(self):
        """
        #24831 -- Cached properties on ManyToOneRel created in QuerySet.delete()
        caused subsequent QuerySet pickling to fail.
        """
        g = Group.objects.create(name='foo')
        m2m = M2MModel.objects.create()
        m2m.groups.add(g)
        Group.objects.all().delete()

        m2ms = M2MModel.objects.prefetch_related('groups')
        m2ms = pickle.loads(pickle.dumps(m2ms))
        self.assertQuerysetEqual(m2ms, [m2m], lambda x: x)

    def test_annotation_with_callable_default(self):
        # Happening.when has a callable default of datetime.datetime.now.
        qs = Happening.objects.annotate(latest_time=models.Max('when'))
        self.assert_pickles(qs)

    def test_missing_django_version_unpickling(self):
        """
        #21430 -- Verifies a warning is raised for querysets that are
        unpickled without a Django version
        """
        qs = Group.missing_django_version_objects.all()
        with warnings.catch_warnings(record=True) as recorded:
            pickle.loads(pickle.dumps(qs))
            msg = force_text(recorded.pop().message)
            self.assertEqual(msg,
                "Pickled queryset instance's Django version is not specified.")

    def test_unsupported_unpickle(self):
        """
        #21430 -- Verifies a warning is raised for querysets that are
        unpickled with a different Django version than the current
        """
        qs = Group.previous_django_version_objects.all()
        with warnings.catch_warnings(record=True) as recorded:
            pickle.loads(pickle.dumps(qs))
            msg = force_text(recorded.pop().message)
            self.assertEqual(
                msg,
                "Pickled queryset instance's Django version 1.0 does not "
                "match the current version %s." % get_version()
            )