from datetime import datetime

from operator import attrgetter

from django.test import TestCase

from models import Person, Group, Membership, CustomMembership, \

    TestNoDefaultsOrNulls, PersonSelfRefM2M, Friendship

class M2mThroughTests(TestCase):

    def setUp(self):

        self.bob = Person.objects.create(name='Bob')

        self.jim = Person.objects.create(name='Jim')

        self.jane = Person.objects.create(name='Jane')

        self.rock = Group.objects.create(name='Rock')

        self.roll = Group.objects.create(name='Roll')

    def test_m2m_through(self):

        # We start out by making sure that the Group 'rock' has no members.

        self.assertQuerysetEqual(

            self.rock.members.all(),

            []

        )

        # To make Jim a member of Group Rock, simply create a Membership object.

        m1 = Membership.objects.create(person=self.jim, group=self.rock)

        # We can do the same for Jane and Rock.

        m2 = Membership.objects.create(person=self.jane, group=self.rock)

        # Let's check to make sure that it worked.  Jane and Jim should be members of Rock.

        self.assertQuerysetEqual(

            self.rock.members.all(), [

                'Jane',

                'Jim'

            ],

            attrgetter("name")

        )

        # Now we can add a bunch more Membership objects to test with.

        m3 = Membership.objects.create(person=self.bob, group=self.roll)

        m4 = Membership.objects.create(person=self.jim, group=self.roll)

        m5 = Membership.objects.create(person=self.jane, group=self.roll)

        # We can get Jim's Group membership as with any ForeignKey.

        self.assertQuerysetEqual(

            self.jim.group_set.all(), [

                'Rock',

                'Roll'

            ],

            attrgetter("name")

        )

        # Querying the intermediary model works like normal.

        self.assertEqual(

            repr(Membership.objects.get(person=self.jane, group=self.rock)),

            '<Membership: Jane is a member of Rock>'

        )

        # It's not only get that works. Filter works like normal as well.

        self.assertQuerysetEqual(

            Membership.objects.filter(person=self.jim), [

                '<Membership: Jim is a member of Rock>',

                '<Membership: Jim is a member of Roll>'

            ]

        )

        self.rock.members.clear()

        # Now there will be no members of Rock.

        self.assertQuerysetEqual(

            self.rock.members.all(),

            []

        )

    def test_forward_descriptors(self):

        # Due to complications with adding via an intermediary model,

        # the add method is not provided.

        self.assertRaises(AttributeError, lambda: self.rock.members.add(self.bob))

        # Create is also disabled as it suffers from the same problems as add.

        self.assertRaises(AttributeError, lambda: self.rock.members.create(name='Anne'))

        # Remove has similar complications, and is not provided either.

        self.assertRaises(AttributeError, lambda: self.rock.members.remove(self.jim))

        m1 = Membership.objects.create(person=self.jim, group=self.rock)

        m2 = Membership.objects.create(person=self.jane, group=self.rock)

        # Here we back up the list of all members of Rock.

        backup = list(self.rock.members.all())

        # ...and we verify that it has worked.

        self.assertEqual(

            [p.name for p in backup],

            ['Jane', 'Jim']

        )

        # The clear function should still work.

        self.rock.members.clear()

        # Now there will be no members of Rock.

        self.assertQuerysetEqual(

            self.rock.members.all(),

            []

        )

        # Assignment should not work with models specifying a through model for many of

        # the same reasons as adding.

        self.assertRaises(AttributeError, setattr, self.rock, "members", backup)

        # Let's re-save those instances that we've cleared.

        m1.save()

        m2.save()

        # Verifying that those instances were re-saved successfully.

        self.assertQuerysetEqual(

            self.rock.members.all(),[

                'Jane',

                'Jim'

            ],

            attrgetter("name")

        )

    def test_reverse_descriptors(self):

        # Due to complications with adding via an intermediary model,

        # the add method is not provided.

        self.assertRaises(AttributeError, lambda: self.bob.group_set.add(self.rock))

        # Create is also disabled as it suffers from the same problems as add.

        self.assertRaises(AttributeError, lambda: self.bob.group_set.create(name="funk"))

        # Remove has similar complications, and is not provided either.

        self.assertRaises(AttributeError, lambda: self.jim.group_set.remove(self.rock))

        m1 = Membership.objects.create(person=self.jim, group=self.rock)

        m2 = Membership.objects.create(person=self.jim, group=self.roll)

        # Here we back up the list of all of Jim's groups.

        backup = list(self.jim.group_set.all())

        self.assertEqual(

            [g.name for g in backup],

            ['Rock', 'Roll']

        )

        # The clear function should still work.

        self.jim.group_set.clear()

        # Now Jim will be in no groups.

        self.assertQuerysetEqual(

            self.jim.group_set.all(),

            []

        )

        # Assignment should not work with models specifying a through model for many of

        # the same reasons as adding.

        self.assertRaises(AttributeError, setattr, self.jim, "group_set", backup)

        # Let's re-save those instances that we've cleared.

        m1.save()

        m2.save()

        # Verifying that those instances were re-saved successfully.

        self.assertQuerysetEqual(

            self.jim.group_set.all(),[

                'Rock',

                'Roll'

            ],

            attrgetter("name")

        )

    def test_custom_tests(self):

        # Let's see if we can query through our second relationship.

        self.assertQuerysetEqual(

            self.rock.custom_members.all(),

            []

        )

        # We can query in the opposite direction as well.

        self.assertQuerysetEqual(

            self.bob.custom.all(),

            []

        )

        cm1 = CustomMembership.objects.create(person=self.bob, group=self.rock)

        cm2 = CustomMembership.objects.create(person=self.jim, group=self.rock)

        # If we get the number of people in Rock, it should be both Bob and Jim.

        self.assertQuerysetEqual(

            self.rock.custom_members.all(),[

                'Bob',

                'Jim'

            ],

            attrgetter("name")

        )

        # Bob should only be in one custom group.

        self.assertQuerysetEqual(

            self.bob.custom.all(),[

                'Rock'

            ],

            attrgetter("name")

        )

        # Let's make sure our new descriptors don't conflict with the FK related_name.

        self.assertQuerysetEqual(

            self.bob.custom_person_related_name.all(),[

                '<CustomMembership: Bob is a member of Rock>'

            ]

        )

    def test_self_referential_tests(self):

        # Let's first create a person who has no friends.

        tony = PersonSelfRefM2M.objects.create(name="Tony")

        self.assertQuerysetEqual(

            tony.friends.all(),

            []

        )

        chris = PersonSelfRefM2M.objects.create(name="Chris")

        f = Friendship.objects.create(first=tony, second=chris, date_friended=datetime.now())

        # Tony should now show that Chris is his friend.

        self.assertQuerysetEqual(

            tony.friends.all(),[

                'Chris'

            ],

            attrgetter("name")

        )

        # But we haven't established that Chris is Tony's Friend.

        self.assertQuerysetEqual(

            chris.friends.all(),

            []

        )

        f2 = Friendship.objects.create(first=chris, second=tony, date_friended=datetime.now())

        # Having added Chris as a friend, let's make sure that his friend set reflects

        # that addition.

        self.assertQuerysetEqual(

            chris.friends.all(),[

                'Tony'

            ],

            attrgetter("name")

        )

        # Chris gets mad and wants to get rid of all of his friends.

        chris.friends.clear()

        # Now he should not have any more friends.

        self.assertQuerysetEqual(

            chris.friends.all(),

            []

        )

        # Since this isn't a symmetrical relation, Tony's friend link still exists.

        self.assertQuerysetEqual(

            tony.friends.all(),[

                'Chris'

            ],

            attrgetter("name")

        )

    def test_query_tests(self):

        m1 = Membership.objects.create(person=self.jim, group=self.rock)

        m2 = Membership.objects.create(person=self.jane, group=self.rock)

        m3 = Membership.objects.create(person=self.bob, group=self.roll)

        m4 = Membership.objects.create(person=self.jim, group=self.roll)

        m5 = Membership.objects.create(person=self.jane, group=self.roll)

        m2.invite_reason = "She was just awesome."

        m2.date_joined = datetime(2006, 1, 1)

        m2.save()

        m3.date_joined = datetime(2004, 1, 1)

        m3.save()

        m5.date_joined = datetime(2004, 1, 1)

        m5.save()

        # We can query for the related model by using its attribute name (members, in

        # this case).

        self.assertQuerysetEqual(

            Group.objects.filter(members__name='Bob'),[

                'Roll'

            ],

            attrgetter("name")

        )

        # To query through the intermediary model, we specify its model name.

        # In this case, membership.

        self.assertQuerysetEqual(

            Group.objects.filter(membership__invite_reason="She was just awesome."),[

                'Rock'

            ],

            attrgetter("name")

        )

        # If we want to query in the reverse direction by the related model, use its

        # model name (group, in this case).

        self.assertQuerysetEqual(

            Person.objects.filter(group__name="Rock"),[

                'Jane',

                'Jim'

            ],

            attrgetter("name")

        )

        cm1 = CustomMembership.objects.create(person=self.bob, group=self.rock)

        cm2 = CustomMembership.objects.create(person=self.jim, group=self.rock)

        # If the m2m field has specified a related_name, using that will work.

        self.assertQuerysetEqual(

            Person.objects.filter(custom__name="Rock"),[

                'Bob',

                'Jim'

            ],

            attrgetter("name")

        )

        # To query through the intermediary model in the reverse direction, we again

        # specify its model name (membership, in this case).

        self.assertQuerysetEqual(

            Person.objects.filter(membership__invite_reason="She was just awesome."),[

                'Jane'

            ],

            attrgetter("name")

        )

        # Let's see all of the groups that Jane joined after 1 Jan 2005:

        self.assertQuerysetEqual(

            Group.objects.filter(membership__date_joined__gt=datetime(2005, 1, 1), membership__person=self.jane),[

                'Rock'

            ],

            attrgetter("name")

        )

        # Queries also work in the reverse direction: Now let's see all of the people

        # that have joined Rock since 1 Jan 2005:

        self.assertQuerysetEqual(

            Person.objects.filter(membership__date_joined__gt=datetime(2005, 1, 1), membership__group=self.rock),[

                'Jane',

                'Jim'

            ],

            attrgetter("name")

        )

        # Conceivably, queries through membership could return correct, but non-unique

        # querysets.  To demonstrate this, we query for all people who have joined a

        # group after 2004:

        self.assertQuerysetEqual(

            Person.objects.filter(membership__date_joined__gt=datetime(2004, 1, 1)),[

                'Jane',

                'Jim',

                'Jim'

            ],

            attrgetter("name")

        )

        # Jim showed up twice, because he joined two groups ('Rock', and 'Roll'):

        self.assertEqual(

            [(m.person.name, m.group.name) for m in Membership.objects.filter(date_joined__gt=datetime(2004, 1, 1))],

            [(u'Jane', u'Rock'), (u'Jim', u'Rock'), (u'Jim', u'Roll')]

        )

        # QuerySet's distinct() method can correct this problem.

        self.assertQuerysetEqual(

            Person.objects.filter(membership__date_joined__gt=datetime(2004, 1, 1)).distinct(),[

                'Jane',

                'Jim'

            ],

            attrgetter("name")

        )