from unittest import mock

from django.core.exceptions import ValidationError
from django.db import IntegrityError, connection, models
from django.db.models import F
from django.db.models.constraints import BaseConstraint
from django.db.models.functions import Lower
from django.db.transaction import atomic
from django.test import SimpleTestCase, TestCase, skipUnlessDBFeature

from .models import (
    ChildModel, Product, UniqueConstraintConditionProduct,
    UniqueConstraintDeferrable, UniqueConstraintInclude,
    UniqueConstraintProduct,
)


def get_constraints(table):
    with connection.cursor() as cursor:
        return connection.introspection.get_constraints(cursor, table)


class BaseConstraintTests(SimpleTestCase):
    def test_constraint_sql(self):
        c = BaseConstraint('name')
        msg = 'This method must be implemented by a subclass.'
        with self.assertRaisesMessage(NotImplementedError, msg):
            c.constraint_sql(None, None)

    def test_contains_expressions(self):
        c = BaseConstraint('name')
        self.assertIs(c.contains_expressions, False)

    def test_create_sql(self):
        c = BaseConstraint('name')
        msg = 'This method must be implemented by a subclass.'
        with self.assertRaisesMessage(NotImplementedError, msg):
            c.create_sql(None, None)

    def test_remove_sql(self):
        c = BaseConstraint('name')
        msg = 'This method must be implemented by a subclass.'
        with self.assertRaisesMessage(NotImplementedError, msg):
            c.remove_sql(None, None)


class CheckConstraintTests(TestCase):
    def test_eq(self):
        check1 = models.Q(price__gt=models.F('discounted_price'))
        check2 = models.Q(price__lt=models.F('discounted_price'))
        self.assertEqual(
            models.CheckConstraint(check=check1, name='price'),
            models.CheckConstraint(check=check1, name='price'),
        )
        self.assertEqual(models.CheckConstraint(check=check1, name='price'), mock.ANY)
        self.assertNotEqual(
            models.CheckConstraint(check=check1, name='price'),
            models.CheckConstraint(check=check1, name='price2'),
        )
        self.assertNotEqual(
            models.CheckConstraint(check=check1, name='price'),
            models.CheckConstraint(check=check2, name='price'),
        )
        self.assertNotEqual(models.CheckConstraint(check=check1, name='price'), 1)

    def test_repr(self):
        constraint = models.CheckConstraint(
            check=models.Q(price__gt=models.F('discounted_price')),
            name='price_gt_discounted_price',
        )
        self.assertEqual(
            repr(constraint),
            "<CheckConstraint: check=(AND: ('price__gt', F(discounted_price))) "
            "name='price_gt_discounted_price'>",
        )

    def test_invalid_check_types(self):
        msg = (
            'CheckConstraint.check must be a Q instance or boolean expression.'
        )
        with self.assertRaisesMessage(TypeError, msg):
            models.CheckConstraint(check=models.F('discounted_price'), name='check')

    def test_deconstruction(self):
        check = models.Q(price__gt=models.F('discounted_price'))
        name = 'price_gt_discounted_price'
        constraint = models.CheckConstraint(check=check, name=name)
        path, args, kwargs = constraint.deconstruct()
        self.assertEqual(path, 'django.db.models.CheckConstraint')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'check': check, 'name': name})

    @skipUnlessDBFeature('supports_table_check_constraints')
    def test_database_constraint(self):
        Product.objects.create(price=10, discounted_price=5)
        with self.assertRaises(IntegrityError):
            Product.objects.create(price=10, discounted_price=20)

    @skipUnlessDBFeature('supports_table_check_constraints')
    def test_database_constraint_unicode(self):
        Product.objects.create(price=10, discounted_price=5, unit='μg/mL')
        with self.assertRaises(IntegrityError):
            Product.objects.create(price=10, discounted_price=7, unit='l')

    @skipUnlessDBFeature('supports_table_check_constraints')
    def test_database_constraint_expression(self):
        Product.objects.create(price=999, discounted_price=5)
        with self.assertRaises(IntegrityError):
            Product.objects.create(price=1000, discounted_price=5)

    @skipUnlessDBFeature('supports_table_check_constraints')
    def test_database_constraint_expressionwrapper(self):
        Product.objects.create(price=499, discounted_price=5)
        with self.assertRaises(IntegrityError):
            Product.objects.create(price=500, discounted_price=5)

    @skipUnlessDBFeature('supports_table_check_constraints', 'can_introspect_check_constraints')
    def test_name(self):
        constraints = get_constraints(Product._meta.db_table)
        for expected_name in (
            'price_gt_discounted_price',
            'constraints_price_lt_1000_raw',
            'constraints_price_neq_500_wrap',
            'constraints_product_price_gt_0',
        ):
            with self.subTest(expected_name):
                self.assertIn(expected_name, constraints)

    @skipUnlessDBFeature('supports_table_check_constraints', 'can_introspect_check_constraints')
    def test_abstract_name(self):
        constraints = get_constraints(ChildModel._meta.db_table)
        self.assertIn('constraints_childmodel_adult', constraints)


class UniqueConstraintTests(TestCase):
    @classmethod
    def setUpTestData(cls):
        cls.p1, cls.p2 = UniqueConstraintProduct.objects.bulk_create([
            UniqueConstraintProduct(name='p1', color='red'),
            UniqueConstraintProduct(name='p2'),
        ])

    def test_eq(self):
        self.assertEqual(
            models.UniqueConstraint(fields=['foo', 'bar'], name='unique'),
            models.UniqueConstraint(fields=['foo', 'bar'], name='unique'),
        )
        self.assertEqual(
            models.UniqueConstraint(fields=['foo', 'bar'], name='unique'),
            mock.ANY,
        )
        self.assertNotEqual(
            models.UniqueConstraint(fields=['foo', 'bar'], name='unique'),
            models.UniqueConstraint(fields=['foo', 'bar'], name='unique2'),
        )
        self.assertNotEqual(
            models.UniqueConstraint(fields=['foo', 'bar'], name='unique'),
            models.UniqueConstraint(fields=['foo', 'baz'], name='unique'),
        )
        self.assertNotEqual(models.UniqueConstraint(fields=['foo', 'bar'], name='unique'), 1)

    def test_eq_with_condition(self):
        self.assertEqual(
            models.UniqueConstraint(
                fields=['foo', 'bar'], name='unique',
                condition=models.Q(foo=models.F('bar'))
            ),
            models.UniqueConstraint(
                fields=['foo', 'bar'], name='unique',
                condition=models.Q(foo=models.F('bar'))),
        )
        self.assertNotEqual(
            models.UniqueConstraint(
                fields=['foo', 'bar'],
                name='unique',
                condition=models.Q(foo=models.F('bar'))
            ),
            models.UniqueConstraint(
                fields=['foo', 'bar'],
                name='unique',
                condition=models.Q(foo=models.F('baz'))
            ),
        )

    def test_eq_with_deferrable(self):
        constraint_1 = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='unique',
            deferrable=models.Deferrable.DEFERRED,
        )
        constraint_2 = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='unique',
            deferrable=models.Deferrable.IMMEDIATE,
        )
        self.assertEqual(constraint_1, constraint_1)
        self.assertNotEqual(constraint_1, constraint_2)

    def test_eq_with_include(self):
        constraint_1 = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='include',
            include=['baz_1'],
        )
        constraint_2 = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='include',
            include=['baz_2'],
        )
        self.assertEqual(constraint_1, constraint_1)
        self.assertNotEqual(constraint_1, constraint_2)

    def test_eq_with_opclasses(self):
        constraint_1 = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='opclasses',
            opclasses=['text_pattern_ops', 'varchar_pattern_ops'],
        )
        constraint_2 = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='opclasses',
            opclasses=['varchar_pattern_ops', 'text_pattern_ops'],
        )
        self.assertEqual(constraint_1, constraint_1)
        self.assertNotEqual(constraint_1, constraint_2)

    def test_eq_with_expressions(self):
        constraint = models.UniqueConstraint(
            Lower('title'),
            F('author'),
            name='book_func_uq',
        )
        same_constraint = models.UniqueConstraint(
            Lower('title'),
            'author',
            name='book_func_uq',
        )
        another_constraint = models.UniqueConstraint(
            Lower('title'),
            name='book_func_uq',
        )
        self.assertEqual(constraint, same_constraint)
        self.assertEqual(constraint, mock.ANY)
        self.assertNotEqual(constraint, another_constraint)

    def test_repr(self):
        fields = ['foo', 'bar']
        name = 'unique_fields'
        constraint = models.UniqueConstraint(fields=fields, name=name)
        self.assertEqual(
            repr(constraint),
            "<UniqueConstraint: fields=('foo', 'bar') name='unique_fields'>",
        )

    def test_repr_with_condition(self):
        constraint = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='unique_fields',
            condition=models.Q(foo=models.F('bar')),
        )
        self.assertEqual(
            repr(constraint),
            "<UniqueConstraint: fields=('foo', 'bar') name='unique_fields' "
            "condition=(AND: ('foo', F(bar)))>",
        )

    def test_repr_with_deferrable(self):
        constraint = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='unique_fields',
            deferrable=models.Deferrable.IMMEDIATE,
        )
        self.assertEqual(
            repr(constraint),
            "<UniqueConstraint: fields=('foo', 'bar') name='unique_fields' "
            "deferrable=Deferrable.IMMEDIATE>",
        )

    def test_repr_with_include(self):
        constraint = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='include_fields',
            include=['baz_1', 'baz_2'],
        )
        self.assertEqual(
            repr(constraint),
            "<UniqueConstraint: fields=('foo', 'bar') name='include_fields' "
            "include=('baz_1', 'baz_2')>",
        )

    def test_repr_with_opclasses(self):
        constraint = models.UniqueConstraint(
            fields=['foo', 'bar'],
            name='opclasses_fields',
            opclasses=['text_pattern_ops', 'varchar_pattern_ops'],
        )
        self.assertEqual(
            repr(constraint),
            "<UniqueConstraint: fields=('foo', 'bar') name='opclasses_fields' "
            "opclasses=['text_pattern_ops', 'varchar_pattern_ops']>",
        )

    def test_repr_with_expressions(self):
        constraint = models.UniqueConstraint(
            Lower('title'),
            F('author'),
            name='book_func_uq',
        )
        self.assertEqual(
            repr(constraint),
            "<UniqueConstraint: expressions=(Lower(F(title)), F(author)) "
            "name='book_func_uq'>",
        )

    def test_deconstruction(self):
        fields = ['foo', 'bar']
        name = 'unique_fields'
        constraint = models.UniqueConstraint(fields=fields, name=name)
        path, args, kwargs = constraint.deconstruct()
        self.assertEqual(path, 'django.db.models.UniqueConstraint')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'fields': tuple(fields), 'name': name})

    def test_deconstruction_with_condition(self):
        fields = ['foo', 'bar']
        name = 'unique_fields'
        condition = models.Q(foo=models.F('bar'))
        constraint = models.UniqueConstraint(fields=fields, name=name, condition=condition)
        path, args, kwargs = constraint.deconstruct()
        self.assertEqual(path, 'django.db.models.UniqueConstraint')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'fields': tuple(fields), 'name': name, 'condition': condition})

    def test_deconstruction_with_deferrable(self):
        fields = ['foo']
        name = 'unique_fields'
        constraint = models.UniqueConstraint(
            fields=fields,
            name=name,
            deferrable=models.Deferrable.DEFERRED,
        )
        path, args, kwargs = constraint.deconstruct()
        self.assertEqual(path, 'django.db.models.UniqueConstraint')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {
            'fields': tuple(fields),
            'name': name,
            'deferrable': models.Deferrable.DEFERRED,
        })

    def test_deconstruction_with_include(self):
        fields = ['foo', 'bar']
        name = 'unique_fields'
        include = ['baz_1', 'baz_2']
        constraint = models.UniqueConstraint(fields=fields, name=name, include=include)
        path, args, kwargs = constraint.deconstruct()
        self.assertEqual(path, 'django.db.models.UniqueConstraint')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {
            'fields': tuple(fields),
            'name': name,
            'include': tuple(include),
        })

    def test_deconstruction_with_opclasses(self):
        fields = ['foo', 'bar']
        name = 'unique_fields'
        opclasses = ['varchar_pattern_ops', 'text_pattern_ops']
        constraint = models.UniqueConstraint(fields=fields, name=name, opclasses=opclasses)
        path, args, kwargs = constraint.deconstruct()
        self.assertEqual(path, 'django.db.models.UniqueConstraint')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {
            'fields': tuple(fields),
            'name': name,
            'opclasses': opclasses,
        })

    def test_deconstruction_with_expressions(self):
        name = 'unique_fields'
        constraint = models.UniqueConstraint(Lower('title'), name=name)
        path, args, kwargs = constraint.deconstruct()
        self.assertEqual(path, 'django.db.models.UniqueConstraint')
        self.assertEqual(args, (Lower('title'),))
        self.assertEqual(kwargs, {'name': name})

    def test_database_constraint(self):
        with self.assertRaises(IntegrityError):
            UniqueConstraintProduct.objects.create(name=self.p1.name, color=self.p1.color)

    @skipUnlessDBFeature('supports_partial_indexes')
    def test_database_constraint_with_condition(self):
        UniqueConstraintConditionProduct.objects.create(name='p1')
        UniqueConstraintConditionProduct.objects.create(name='p2')
        with self.assertRaises(IntegrityError):
            UniqueConstraintConditionProduct.objects.create(name='p1')

    def test_model_validation(self):
        msg = 'Unique constraint product with this Name and Color already exists.'
        with self.assertRaisesMessage(ValidationError, msg):
            UniqueConstraintProduct(name=self.p1.name, color=self.p1.color).validate_unique()

    @skipUnlessDBFeature('supports_partial_indexes')
    def test_model_validation_with_condition(self):
        """Partial unique constraints are ignored by Model.validate_unique()."""
        obj1 = UniqueConstraintConditionProduct.objects.create(name='p1', color='red')
        obj2 = UniqueConstraintConditionProduct.objects.create(name='p2')
        UniqueConstraintConditionProduct(name=obj1.name, color='blue').validate_unique()
        UniqueConstraintConditionProduct(name=obj2.name).validate_unique()

    def test_name(self):
        constraints = get_constraints(UniqueConstraintProduct._meta.db_table)
        expected_name = 'name_color_uniq'
        self.assertIn(expected_name, constraints)

    def test_condition_must_be_q(self):
        with self.assertRaisesMessage(ValueError, 'UniqueConstraint.condition must be a Q instance.'):
            models.UniqueConstraint(name='uniq', fields=['name'], condition='invalid')

    @skipUnlessDBFeature('supports_deferrable_unique_constraints')
    def test_initially_deferred_database_constraint(self):
        obj_1 = UniqueConstraintDeferrable.objects.create(name='p1', shelf='front')
        obj_2 = UniqueConstraintDeferrable.objects.create(name='p2', shelf='back')

        def swap():
            obj_1.name, obj_2.name = obj_2.name, obj_1.name
            obj_1.save()
            obj_2.save()

        swap()
        # Behavior can be changed with SET CONSTRAINTS.
        with self.assertRaises(IntegrityError):
            with atomic(), connection.cursor() as cursor:
                constraint_name = connection.ops.quote_name('name_init_deferred_uniq')
                cursor.execute('SET CONSTRAINTS %s IMMEDIATE' % constraint_name)
                swap()

    @skipUnlessDBFeature('supports_deferrable_unique_constraints')
    def test_initially_immediate_database_constraint(self):
        obj_1 = UniqueConstraintDeferrable.objects.create(name='p1', shelf='front')
        obj_2 = UniqueConstraintDeferrable.objects.create(name='p2', shelf='back')
        obj_1.shelf, obj_2.shelf = obj_2.shelf, obj_1.shelf
        with self.assertRaises(IntegrityError), atomic():
            obj_1.save()
        # Behavior can be changed with SET CONSTRAINTS.
        with connection.cursor() as cursor:
            constraint_name = connection.ops.quote_name('sheld_init_immediate_uniq')
            cursor.execute('SET CONSTRAINTS %s DEFERRED' % constraint_name)
            obj_1.save()
            obj_2.save()

    def test_deferrable_with_condition(self):
        message = 'UniqueConstraint with conditions cannot be deferred.'
        with self.assertRaisesMessage(ValueError, message):
            models.UniqueConstraint(
                fields=['name'],
                name='name_without_color_unique',
                condition=models.Q(color__isnull=True),
                deferrable=models.Deferrable.DEFERRED,
            )

    def test_deferrable_with_include(self):
        message = 'UniqueConstraint with include fields cannot be deferred.'
        with self.assertRaisesMessage(ValueError, message):
            models.UniqueConstraint(
                fields=['name'],
                name='name_inc_color_color_unique',
                include=['color'],
                deferrable=models.Deferrable.DEFERRED,
            )

    def test_deferrable_with_opclasses(self):
        message = 'UniqueConstraint with opclasses cannot be deferred.'
        with self.assertRaisesMessage(ValueError, message):
            models.UniqueConstraint(
                fields=['name'],
                name='name_text_pattern_ops_unique',
                opclasses=['text_pattern_ops'],
                deferrable=models.Deferrable.DEFERRED,
            )

    def test_deferrable_with_expressions(self):
        message = 'UniqueConstraint with expressions cannot be deferred.'
        with self.assertRaisesMessage(ValueError, message):
            models.UniqueConstraint(
                Lower('name'),
                name='deferred_expression_unique',
                deferrable=models.Deferrable.DEFERRED,
            )

    def test_invalid_defer_argument(self):
        message = 'UniqueConstraint.deferrable must be a Deferrable instance.'
        with self.assertRaisesMessage(ValueError, message):
            models.UniqueConstraint(
                fields=['name'],
                name='name_invalid',
                deferrable='invalid',
            )

    @skipUnlessDBFeature(
        'supports_table_check_constraints',
        'supports_covering_indexes',
    )
    def test_include_database_constraint(self):
        UniqueConstraintInclude.objects.create(name='p1', color='red')
        with self.assertRaises(IntegrityError):
            UniqueConstraintInclude.objects.create(name='p1', color='blue')

    def test_invalid_include_argument(self):
        msg = 'UniqueConstraint.include must be a list or tuple.'
        with self.assertRaisesMessage(ValueError, msg):
            models.UniqueConstraint(
                name='uniq_include',
                fields=['field'],
                include='other',
            )

    def test_invalid_opclasses_argument(self):
        msg = 'UniqueConstraint.opclasses must be a list or tuple.'
        with self.assertRaisesMessage(ValueError, msg):
            models.UniqueConstraint(
                name='uniq_opclasses',
                fields=['field'],
                opclasses='jsonb_path_ops',
            )

    def test_opclasses_and_fields_same_length(self):
        msg = (
            'UniqueConstraint.fields and UniqueConstraint.opclasses must have '
            'the same number of elements.'
        )
        with self.assertRaisesMessage(ValueError, msg):
            models.UniqueConstraint(
                name='uniq_opclasses',
                fields=['field'],
                opclasses=['foo', 'bar'],
            )

    def test_requires_field_or_expression(self):
        msg = (
            'At least one field or expression is required to define a unique '
            'constraint.'
        )
        with self.assertRaisesMessage(ValueError, msg):
            models.UniqueConstraint(name='name')

    def test_expressions_and_fields_mutually_exclusive(self):
        msg = 'UniqueConstraint.fields and expressions are mutually exclusive.'
        with self.assertRaisesMessage(ValueError, msg):
            models.UniqueConstraint(Lower('field_1'), fields=['field_2'], name='name')

    def test_expressions_with_opclasses(self):
        msg = (
            'UniqueConstraint.opclasses cannot be used with expressions. Use '
            'django.contrib.postgres.indexes.OpClass() instead.'
        )
        with self.assertRaisesMessage(ValueError, msg):
            models.UniqueConstraint(
                Lower('field'),
                name='test_func_opclass',
                opclasses=['jsonb_path_ops'],
            )

    def test_requires_name(self):
        msg = 'A unique constraint must be named.'
        with self.assertRaisesMessage(ValueError, msg):
            models.UniqueConstraint(fields=['field'])
