from django.core.exceptions import FieldError
from django.test import TestCase

from .models import (
    Entry, Line, Post, RegressionModelSplit, SelfRefer, SelfReferChild,
    SelfReferChildSibling, Tag, TagCollection, Worksheet,
)


class M2MRegressionTests(TestCase):
    def test_multiple_m2m(self):
        # Multiple m2m references to model must be distinguished when
        # accessing the relations through an instance attribute.

        s1 = SelfRefer.objects.create(name='s1')
        s2 = SelfRefer.objects.create(name='s2')
        s3 = SelfRefer.objects.create(name='s3')
        s1.references.add(s2)
        s1.related.add(s3)

        e1 = Entry.objects.create(name='e1')
        t1 = Tag.objects.create(name='t1')
        t2 = Tag.objects.create(name='t2')

        e1.topics.add(t1)
        e1.related.add(t2)

        self.assertSequenceEqual(s1.references.all(), [s2])
        self.assertSequenceEqual(s1.related.all(), [s3])

        self.assertSequenceEqual(e1.topics.all(), [t1])
        self.assertSequenceEqual(e1.related.all(), [t2])

    def test_m2m_managers_reused(self):
        s1 = SelfRefer.objects.create(name='s1')
        e1 = Entry.objects.create(name='e1')
        self.assertIs(s1.references, s1.references)
        self.assertIs(s1.related, s1.related)
        self.assertIs(e1.topics, e1.topics)
        self.assertIs(e1.related, e1.related)

    def test_internal_related_name_not_in_error_msg(self):
        # The secret internal related names for self-referential many-to-many
        # fields shouldn't appear in the list when an error is made.
        with self.assertRaisesMessage(
            FieldError,
            "Choices are: id, name, references, related, selfreferchild, selfreferchildsibling",
        ):
            SelfRefer.objects.filter(porcupine='fred')

    def test_m2m_inheritance_symmetry(self):
        # Test to ensure that the relationship between two inherited models
        # with a self-referential m2m field maintains symmetry

        sr_child = SelfReferChild(name="Hanna")
        sr_child.save()

        sr_sibling = SelfReferChildSibling(name="Beth")
        sr_sibling.save()
        sr_child.related.add(sr_sibling)

        self.assertSequenceEqual(sr_child.related.all(), [sr_sibling.selfrefer_ptr])
        self.assertSequenceEqual(sr_sibling.related.all(), [sr_child.selfrefer_ptr])

    def test_m2m_pk_field_type(self):
        # Regression for #11311 - The primary key for models in a m2m relation
        # doesn't have to be an AutoField

        w = Worksheet(id='abc')
        w.save()
        w.delete()

    def test_add_m2m_with_base_class(self):
        # Regression for #11956 -- You can add an object to a m2m with the
        # base class without causing integrity errors

        t1 = Tag.objects.create(name='t1')
        t2 = Tag.objects.create(name='t2')

        c1 = TagCollection.objects.create(name='c1')
        c1.tags.set([t1, t2])
        c1 = TagCollection.objects.get(name='c1')

        self.assertCountEqual(c1.tags.all(), [t1, t2])
        self.assertCountEqual(t1.tag_collections.all(), [c1])

    def test_manager_class_caching(self):
        e1 = Entry.objects.create()
        e2 = Entry.objects.create()
        t1 = Tag.objects.create()
        t2 = Tag.objects.create()

        # Get same manager twice in a row:
        self.assertIs(t1.entry_set.__class__, t1.entry_set.__class__)
        self.assertIs(e1.topics.__class__, e1.topics.__class__)

        # Get same manager for different instances
        self.assertIs(e1.topics.__class__, e2.topics.__class__)
        self.assertIs(t1.entry_set.__class__, t2.entry_set.__class__)

    def test_m2m_abstract_split(self):
        # Regression for #19236 - an abstract class with a 'split' method
        # causes a TypeError in add_lazy_relation
        m1 = RegressionModelSplit(name='1')
        m1.save()

    def test_assigning_invalid_data_to_m2m_doesnt_clear_existing_relations(self):
        t1 = Tag.objects.create(name='t1')
        t2 = Tag.objects.create(name='t2')
        c1 = TagCollection.objects.create(name='c1')
        c1.tags.set([t1, t2])

        with self.assertRaisesMessage(TypeError, "'int' object is not iterable"):
            c1.tags.set(7)

        c1.refresh_from_db()
        self.assertSequenceEqual(c1.tags.order_by('name'), [t1, t2])

    def test_multiple_forwards_only_m2m(self):
        # Regression for #24505 - Multiple ManyToManyFields to same "to"
        # model with related_name set to '+'.
        foo = Line.objects.create(name='foo')
        bar = Line.objects.create(name='bar')
        post = Post.objects.create()
        post.primary_lines.add(foo)
        post.secondary_lines.add(bar)
        self.assertSequenceEqual(post.primary_lines.all(), [foo])
        self.assertSequenceEqual(post.secondary_lines.all(), [bar])