import datetime
from unittest import skipUnless

from django.db import connection
from django.db.models import CASCADE, ForeignKey, Index, Q
from django.db.models.functions import Lower
from django.test import (
    TestCase,
    TransactionTestCase,
    skipIfDBFeature,
    skipUnlessDBFeature,
)
from django.test.utils import override_settings
from django.utils import timezone

from .models import (
    Article,
    ArticleTranslation,
    IndexedArticle2,
    IndexTogetherSingleList,
)


class SchemaIndexesTests(TestCase):
    """
    Test index handling by the db.backends.schema infrastructure.
    """

    def test_index_name_hash(self):
        """
        Index names should be deterministic.
        """
        editor = connection.schema_editor()
        index_name = editor._create_index_name(
            table_name=Article._meta.db_table,
            column_names=("c1",),
            suffix="123",
        )
        self.assertEqual(index_name, "indexes_article_c1_a52bd80b123")

    def test_index_name(self):
        """
        Index names on the built-in database backends::
            * Are truncated as needed.
            * Include all the column names.
            * Include a deterministic hash.
        """
        long_name = "l%sng" % ("o" * 100)
        editor = connection.schema_editor()
        index_name = editor._create_index_name(
            table_name=Article._meta.db_table,
            column_names=("c1", "c2", long_name),
            suffix="ix",
        )
        expected = {
            "mysql": "indexes_article_c1_c2_looooooooooooooooooo_255179b2ix",
            "oracle": "indexes_a_c1_c2_loo_255179b2ix",
            "postgresql": "indexes_article_c1_c2_loooooooooooooooooo_255179b2ix",
            "sqlite": "indexes_article_c1_c2_l%sng_255179b2ix" % ("o" * 100),
        }
        if connection.vendor not in expected:
            self.skipTest(
                "This test is only supported on the built-in database backends."
            )
        self.assertEqual(index_name, expected[connection.vendor])

    def test_index_together(self):
        editor = connection.schema_editor()
        index_sql = [str(statement) for statement in editor._model_indexes_sql(Article)]
        self.assertEqual(len(index_sql), 1)
        # Ensure the index name is properly quoted
        self.assertIn(
            connection.ops.quote_name(
                editor._create_index_name(
                    Article._meta.db_table, ["headline", "pub_date"], suffix="_idx"
                )
            ),
            index_sql[0],
        )

    def test_index_together_single_list(self):
        # Test for using index_together with a single list (#22172)
        index_sql = connection.schema_editor()._model_indexes_sql(
            IndexTogetherSingleList
        )
        self.assertEqual(len(index_sql), 1)

    def test_columns_list_sql(self):
        index = Index(fields=["headline"], name="whitespace_idx")
        editor = connection.schema_editor()
        self.assertIn(
            "(%s)" % editor.quote_name("headline"),
            str(index.create_sql(Article, editor)),
        )

    @skipUnlessDBFeature("supports_index_column_ordering")
    def test_descending_columns_list_sql(self):
        index = Index(fields=["-headline"], name="whitespace_idx")
        editor = connection.schema_editor()
        self.assertIn(
            "(%s DESC)" % editor.quote_name("headline"),
            str(index.create_sql(Article, editor)),
        )


class SchemaIndexesNotPostgreSQLTests(TransactionTestCase):
    available_apps = ["indexes"]

    def test_create_index_ignores_opclasses(self):
        index = Index(
            name="test_ops_class",
            fields=["headline"],
            opclasses=["varchar_pattern_ops"],
        )
        with connection.schema_editor() as editor:
            # This would error if opclasses weren't ignored.
            editor.add_index(IndexedArticle2, index)


# The `condition` parameter is ignored by databases that don't support partial
# indexes.
@skipIfDBFeature("supports_partial_indexes")
class PartialIndexConditionIgnoredTests(TransactionTestCase):
    available_apps = ["indexes"]

    def test_condition_ignored(self):
        index = Index(
            name="test_condition_ignored",
            fields=["published"],
            condition=Q(published=True),
        )
        with connection.schema_editor() as editor:
            # This would error if condition weren't ignored.
            editor.add_index(Article, index)

        self.assertNotIn(
            "WHERE %s" % editor.quote_name("published"),
            str(index.create_sql(Article, editor)),
        )


@skipUnless(connection.vendor == "postgresql", "PostgreSQL tests")
class SchemaIndexesPostgreSQLTests(TransactionTestCase):
    available_apps = ["indexes"]
    get_opclass_query = """
        SELECT opcname, c.relname FROM pg_opclass AS oc
        JOIN pg_index as i on oc.oid = ANY(i.indclass)
        JOIN pg_class as c on c.oid = i.indexrelid
        WHERE c.relname = '%s'
    """

    def test_text_indexes(self):
        """Test creation of PostgreSQL-specific text indexes (#12234)"""
        from .models import IndexedArticle

        index_sql = [
            str(statement)
            for statement in connection.schema_editor()._model_indexes_sql(
                IndexedArticle
            )
        ]
        self.assertEqual(len(index_sql), 5)
        self.assertIn('("headline" varchar_pattern_ops)', index_sql[1])
        self.assertIn('("body" text_pattern_ops)', index_sql[3])
        # unique=True and db_index=True should only create the varchar-specific
        # index (#19441).
        self.assertIn('("slug" varchar_pattern_ops)', index_sql[4])

    def test_virtual_relation_indexes(self):
        """Test indexes are not created for related objects"""
        index_sql = connection.schema_editor()._model_indexes_sql(Article)
        self.assertEqual(len(index_sql), 1)

    def test_ops_class(self):
        index = Index(
            name="test_ops_class",
            fields=["headline"],
            opclasses=["varchar_pattern_ops"],
        )
        with connection.schema_editor() as editor:
            editor.add_index(IndexedArticle2, index)
        with editor.connection.cursor() as cursor:
            cursor.execute(self.get_opclass_query % "test_ops_class")
            self.assertEqual(
                cursor.fetchall(), [("varchar_pattern_ops", "test_ops_class")]
            )

    def test_ops_class_multiple_columns(self):
        index = Index(
            name="test_ops_class_multiple",
            fields=["headline", "body"],
            opclasses=["varchar_pattern_ops", "text_pattern_ops"],
        )
        with connection.schema_editor() as editor:
            editor.add_index(IndexedArticle2, index)
        with editor.connection.cursor() as cursor:
            cursor.execute(self.get_opclass_query % "test_ops_class_multiple")
            expected_ops_classes = (
                ("varchar_pattern_ops", "test_ops_class_multiple"),
                ("text_pattern_ops", "test_ops_class_multiple"),
            )
            self.assertCountEqual(cursor.fetchall(), expected_ops_classes)

    def test_ops_class_partial(self):
        index = Index(
            name="test_ops_class_partial",
            fields=["body"],
            opclasses=["text_pattern_ops"],
            condition=Q(headline__contains="China"),
        )
        with connection.schema_editor() as editor:
            editor.add_index(IndexedArticle2, index)
        with editor.connection.cursor() as cursor:
            cursor.execute(self.get_opclass_query % "test_ops_class_partial")
            self.assertCountEqual(
                cursor.fetchall(), [("text_pattern_ops", "test_ops_class_partial")]
            )

    def test_ops_class_partial_tablespace(self):
        indexname = "test_ops_class_tblspace"
        index = Index(
            name=indexname,
            fields=["body"],
            opclasses=["text_pattern_ops"],
            condition=Q(headline__contains="China"),
            db_tablespace="pg_default",
        )
        with connection.schema_editor() as editor:
            editor.add_index(IndexedArticle2, index)
            self.assertIn(
                'TABLESPACE "pg_default" ',
                str(index.create_sql(IndexedArticle2, editor)),
            )
        with editor.connection.cursor() as cursor:
            cursor.execute(self.get_opclass_query % indexname)
            self.assertCountEqual(cursor.fetchall(), [("text_pattern_ops", indexname)])

    def test_ops_class_descending(self):
        indexname = "test_ops_class_ordered"
        index = Index(
            name=indexname,
            fields=["-body"],
            opclasses=["text_pattern_ops"],
        )
        with connection.schema_editor() as editor:
            editor.add_index(IndexedArticle2, index)
        with editor.connection.cursor() as cursor:
            cursor.execute(self.get_opclass_query % indexname)
            self.assertCountEqual(cursor.fetchall(), [("text_pattern_ops", indexname)])

    def test_ops_class_descending_partial(self):
        indexname = "test_ops_class_ordered_partial"
        index = Index(
            name=indexname,
            fields=["-body"],
            opclasses=["text_pattern_ops"],
            condition=Q(headline__contains="China"),
        )
        with connection.schema_editor() as editor:
            editor.add_index(IndexedArticle2, index)
        with editor.connection.cursor() as cursor:
            cursor.execute(self.get_opclass_query % indexname)
            self.assertCountEqual(cursor.fetchall(), [("text_pattern_ops", indexname)])

    @skipUnlessDBFeature("supports_covering_indexes")
    def test_ops_class_include(self):
        index_name = "test_ops_class_include"
        index = Index(
            name=index_name,
            fields=["body"],
            opclasses=["text_pattern_ops"],
            include=["headline"],
        )
        with connection.schema_editor() as editor:
            editor.add_index(IndexedArticle2, index)
        with editor.connection.cursor() as cursor:
            cursor.execute(self.get_opclass_query % index_name)
            self.assertCountEqual(cursor.fetchall(), [("text_pattern_ops", index_name)])

    @skipUnlessDBFeature("supports_covering_indexes")
    def test_ops_class_include_tablespace(self):
        index_name = "test_ops_class_include_tblspace"
        index = Index(
            name=index_name,
            fields=["body"],
            opclasses=["text_pattern_ops"],
            include=["headline"],
            db_tablespace="pg_default",
        )
        with connection.schema_editor() as editor:
            editor.add_index(IndexedArticle2, index)
            self.assertIn(
                'TABLESPACE "pg_default"',
                str(index.create_sql(IndexedArticle2, editor)),
            )
        with editor.connection.cursor() as cursor:
            cursor.execute(self.get_opclass_query % index_name)
            self.assertCountEqual(cursor.fetchall(), [("text_pattern_ops", index_name)])

    def test_ops_class_columns_lists_sql(self):
        index = Index(
            fields=["headline"],
            name="whitespace_idx",
            opclasses=["text_pattern_ops"],
        )
        with connection.schema_editor() as editor:
            self.assertIn(
                "(%s text_pattern_ops)" % editor.quote_name("headline"),
                str(index.create_sql(Article, editor)),
            )

    def test_ops_class_descending_columns_list_sql(self):
        index = Index(
            fields=["-headline"],
            name="whitespace_idx",
            opclasses=["text_pattern_ops"],
        )
        with connection.schema_editor() as editor:
            self.assertIn(
                "(%s text_pattern_ops DESC)" % editor.quote_name("headline"),
                str(index.create_sql(Article, editor)),
            )


@skipUnless(connection.vendor == "mysql", "MySQL tests")
class SchemaIndexesMySQLTests(TransactionTestCase):
    available_apps = ["indexes"]

    def test_no_index_for_foreignkey(self):
        """
        MySQL on InnoDB already creates indexes automatically for foreign keys.
        (#14180). An index should be created if db_constraint=False (#26171).
        """
        with connection.cursor() as cursor:
            storage = connection.introspection.get_storage_engine(
                cursor,
                ArticleTranslation._meta.db_table,
            )
        if storage != "InnoDB":
            self.skipTest("This test only applies to the InnoDB storage engine")
        index_sql = [
            str(statement)
            for statement in connection.schema_editor()._model_indexes_sql(
                ArticleTranslation
            )
        ]
        self.assertEqual(
            index_sql,
            [
                "CREATE INDEX "
                "`indexes_articletranslation_article_no_constraint_id_d6c0806b` "
                "ON `indexes_articletranslation` (`article_no_constraint_id`)"
            ],
        )

        # The index also shouldn't be created if the ForeignKey is added after
        # the model was created.
        field_created = False
        try:
            with connection.schema_editor() as editor:
                new_field = ForeignKey(Article, CASCADE)
                new_field.set_attributes_from_name("new_foreign_key")
                editor.add_field(ArticleTranslation, new_field)
                field_created = True
                # No deferred SQL. The FK constraint is included in the
                # statement to add the field.
                self.assertFalse(editor.deferred_sql)
        finally:
            if field_created:
                with connection.schema_editor() as editor:
                    editor.remove_field(ArticleTranslation, new_field)


@skipUnlessDBFeature("supports_partial_indexes")
# SQLite doesn't support timezone-aware datetimes when USE_TZ is False.
@override_settings(USE_TZ=True)
class PartialIndexTests(TransactionTestCase):
    # Schema editor is used to create the index to test that it works.
    available_apps = ["indexes"]

    def test_partial_index(self):
        with connection.schema_editor() as editor:
            index = Index(
                name="recent_article_idx",
                fields=["pub_date"],
                condition=Q(
                    pub_date__gt=datetime.datetime(
                        year=2015,
                        month=1,
                        day=1,
                        # PostgreSQL would otherwise complain about the lookup
                        # being converted to a mutable function (by removing
                        # the timezone in the cast) which is forbidden.
                        tzinfo=timezone.get_current_timezone(),
                    ),
                ),
            )
            self.assertIn(
                "WHERE %s" % editor.quote_name("pub_date"),
                str(index.create_sql(Article, schema_editor=editor)),
            )
            editor.add_index(index=index, model=Article)
            with connection.cursor() as cursor:
                self.assertIn(
                    index.name,
                    connection.introspection.get_constraints(
                        cursor=cursor,
                        table_name=Article._meta.db_table,
                    ),
                )
            editor.remove_index(index=index, model=Article)

    def test_integer_restriction_partial(self):
        with connection.schema_editor() as editor:
            index = Index(
                name="recent_article_idx",
                fields=["id"],
                condition=Q(pk__gt=1),
            )
            self.assertIn(
                "WHERE %s" % editor.quote_name("id"),
                str(index.create_sql(Article, schema_editor=editor)),
            )
            editor.add_index(index=index, model=Article)
            with connection.cursor() as cursor:
                self.assertIn(
                    index.name,
                    connection.introspection.get_constraints(
                        cursor=cursor,
                        table_name=Article._meta.db_table,
                    ),
                )
            editor.remove_index(index=index, model=Article)

    def test_boolean_restriction_partial(self):
        with connection.schema_editor() as editor:
            index = Index(
                name="published_index",
                fields=["published"],
                condition=Q(published=True),
            )
            self.assertIn(
                "WHERE %s" % editor.quote_name("published"),
                str(index.create_sql(Article, schema_editor=editor)),
            )
            editor.add_index(index=index, model=Article)
            with connection.cursor() as cursor:
                self.assertIn(
                    index.name,
                    connection.introspection.get_constraints(
                        cursor=cursor,
                        table_name=Article._meta.db_table,
                    ),
                )
            editor.remove_index(index=index, model=Article)

    @skipUnlessDBFeature("supports_functions_in_partial_indexes")
    def test_multiple_conditions(self):
        with connection.schema_editor() as editor:
            index = Index(
                name="recent_article_idx",
                fields=["pub_date", "headline"],
                condition=(
                    Q(
                        pub_date__gt=datetime.datetime(
                            year=2015,
                            month=1,
                            day=1,
                            tzinfo=timezone.get_current_timezone(),
                        )
                    )
                    & Q(headline__contains="China")
                ),
            )
            sql = str(index.create_sql(Article, schema_editor=editor))
            where = sql.find("WHERE")
            self.assertIn("WHERE (%s" % editor.quote_name("pub_date"), sql)
            # Because each backend has different syntax for the operators,
            # check ONLY the occurrence of headline in the SQL.
            self.assertGreater(sql.rfind("headline"), where)
            editor.add_index(index=index, model=Article)
            with connection.cursor() as cursor:
                self.assertIn(
                    index.name,
                    connection.introspection.get_constraints(
                        cursor=cursor,
                        table_name=Article._meta.db_table,
                    ),
                )
            editor.remove_index(index=index, model=Article)

    def test_is_null_condition(self):
        with connection.schema_editor() as editor:
            index = Index(
                name="recent_article_idx",
                fields=["pub_date"],
                condition=Q(pub_date__isnull=False),
            )
            self.assertIn(
                "WHERE %s IS NOT NULL" % editor.quote_name("pub_date"),
                str(index.create_sql(Article, schema_editor=editor)),
            )
            editor.add_index(index=index, model=Article)
            with connection.cursor() as cursor:
                self.assertIn(
                    index.name,
                    connection.introspection.get_constraints(
                        cursor=cursor,
                        table_name=Article._meta.db_table,
                    ),
                )
            editor.remove_index(index=index, model=Article)

    @skipUnlessDBFeature("supports_expression_indexes")
    def test_partial_func_index(self):
        index_name = "partial_func_idx"
        index = Index(
            Lower("headline").desc(),
            name=index_name,
            condition=Q(pub_date__isnull=False),
        )
        with connection.schema_editor() as editor:
            editor.add_index(index=index, model=Article)
            sql = index.create_sql(Article, schema_editor=editor)
        table = Article._meta.db_table
        self.assertIs(sql.references_column(table, "headline"), True)
        sql = str(sql)
        self.assertIn("LOWER(%s)" % editor.quote_name("headline"), sql)
        self.assertIn(
            "WHERE %s IS NOT NULL" % editor.quote_name("pub_date"),
            sql,
        )
        self.assertGreater(sql.find("WHERE"), sql.find("LOWER"))
        with connection.cursor() as cursor:
            constraints = connection.introspection.get_constraints(
                cursor=cursor,
                table_name=table,
            )
        self.assertIn(index_name, constraints)
        if connection.features.supports_index_column_ordering:
            self.assertEqual(constraints[index_name]["orders"], ["DESC"])
        with connection.schema_editor() as editor:
            editor.remove_index(Article, index)
        with connection.cursor() as cursor:
            self.assertNotIn(
                index_name,
                connection.introspection.get_constraints(
                    cursor=cursor,
                    table_name=table,
                ),
            )


@skipUnlessDBFeature("supports_covering_indexes")
class CoveringIndexTests(TransactionTestCase):
    available_apps = ["indexes"]

    def test_covering_index(self):
        index = Index(
            name="covering_headline_idx",
            fields=["headline"],
            include=["pub_date", "published"],
        )
        with connection.schema_editor() as editor:
            self.assertIn(
                "(%s) INCLUDE (%s, %s)"
                % (
                    editor.quote_name("headline"),
                    editor.quote_name("pub_date"),
                    editor.quote_name("published"),
                ),
                str(index.create_sql(Article, editor)),
            )
            editor.add_index(Article, index)
            with connection.cursor() as cursor:
                constraints = connection.introspection.get_constraints(
                    cursor=cursor,
                    table_name=Article._meta.db_table,
                )
                self.assertIn(index.name, constraints)
                self.assertEqual(
                    constraints[index.name]["columns"],
                    ["headline", "pub_date", "published"],
                )
            editor.remove_index(Article, index)
            with connection.cursor() as cursor:
                self.assertNotIn(
                    index.name,
                    connection.introspection.get_constraints(
                        cursor=cursor,
                        table_name=Article._meta.db_table,
                    ),
                )

    def test_covering_partial_index(self):
        index = Index(
            name="covering_partial_headline_idx",
            fields=["headline"],
            include=["pub_date"],
            condition=Q(pub_date__isnull=False),
        )
        with connection.schema_editor() as editor:
            self.assertIn(
                "(%s) INCLUDE (%s) WHERE %s "
                % (
                    editor.quote_name("headline"),
                    editor.quote_name("pub_date"),
                    editor.quote_name("pub_date"),
                ),
                str(index.create_sql(Article, editor)),
            )
            editor.add_index(Article, index)
            with connection.cursor() as cursor:
                constraints = connection.introspection.get_constraints(
                    cursor=cursor,
                    table_name=Article._meta.db_table,
                )
                self.assertIn(index.name, constraints)
                self.assertEqual(
                    constraints[index.name]["columns"],
                    ["headline", "pub_date"],
                )
            editor.remove_index(Article, index)
            with connection.cursor() as cursor:
                self.assertNotIn(
                    index.name,
                    connection.introspection.get_constraints(
                        cursor=cursor,
                        table_name=Article._meta.db_table,
                    ),
                )

    @skipUnlessDBFeature("supports_expression_indexes")
    def test_covering_func_index(self):
        index_name = "covering_func_headline_idx"
        index = Index(Lower("headline"), name=index_name, include=["pub_date"])
        with connection.schema_editor() as editor:
            editor.add_index(index=index, model=Article)
            sql = index.create_sql(Article, schema_editor=editor)
        table = Article._meta.db_table
        self.assertIs(sql.references_column(table, "headline"), True)
        sql = str(sql)
        self.assertIn("LOWER(%s)" % editor.quote_name("headline"), sql)
        self.assertIn("INCLUDE (%s)" % editor.quote_name("pub_date"), sql)
        self.assertGreater(sql.find("INCLUDE"), sql.find("LOWER"))
        with connection.cursor() as cursor:
            constraints = connection.introspection.get_constraints(
                cursor=cursor,
                table_name=table,
            )
        self.assertIn(index_name, constraints)
        self.assertIn("pub_date", constraints[index_name]["columns"])
        with connection.schema_editor() as editor:
            editor.remove_index(Article, index)
        with connection.cursor() as cursor:
            self.assertNotIn(
                index_name,
                connection.introspection.get_constraints(
                    cursor=cursor,
                    table_name=table,
                ),
            )


@skipIfDBFeature("supports_covering_indexes")
class CoveringIndexIgnoredTests(TransactionTestCase):
    available_apps = ["indexes"]

    def test_covering_ignored(self):
        index = Index(
            name="test_covering_ignored",
            fields=["headline"],
            include=["pub_date"],
        )
        with connection.schema_editor() as editor:
            editor.add_index(Article, index)
        self.assertNotIn(
            "INCLUDE (%s)" % editor.quote_name("headline"),
            str(index.create_sql(Article, editor)),
        )