from unittest import skipUnless

from django.db import connection, connections
from django.test import TestCase


@skipUnless(connection.vendor == "mysql", "MySQL tests")
class ParsingTests(TestCase):
    def test_parse_constraint_columns(self):
        _parse_constraint_columns = connection.introspection._parse_constraint_columns
        tests = (
            ("`height` >= 0", ["height"], ["height"]),
            ("`cost` BETWEEN 1 AND 10", ["cost"], ["cost"]),
            ("`ref1` > `ref2`", ["id", "ref1", "ref2"], ["ref1", "ref2"]),
            (
                "`start` IS NULL OR `end` IS NULL OR `start` < `end`",
                ["id", "start", "end"],
                ["start", "end"],
            ),
            ("JSON_VALID(`json_field`)", ["json_field"], ["json_field"]),
            ("CHAR_LENGTH(`name`) > 2", ["name"], ["name"]),
            ("lower(`ref1`) != 'test'", ["id", "owe", "ref1"], ["ref1"]),
            ("lower(`ref1`) != 'test'", ["id", "lower", "ref1"], ["ref1"]),
            ("`name` LIKE 'test%'", ["name"], ["name"]),
        )
        for check_clause, table_columns, expected_columns in tests:
            with self.subTest(check_clause):
                check_columns = _parse_constraint_columns(check_clause, table_columns)
                self.assertEqual(list(check_columns), expected_columns)


@skipUnless(connection.vendor == "mysql", "MySQL tests")
class StorageEngineTests(TestCase):
    databases = {"default", "other"}

    def test_get_storage_engine(self):
        table_name = "test_storage_engine"
        create_sql = "CREATE TABLE %s (id INTEGER) ENGINE = %%s" % table_name
        drop_sql = "DROP TABLE %s" % table_name
        default_connection = connections["default"]
        other_connection = connections["other"]
        try:
            with default_connection.cursor() as cursor:
                cursor.execute(create_sql % "InnoDB")
                self.assertEqual(
                    default_connection.introspection.get_storage_engine(
                        cursor, table_name
                    ),
                    "InnoDB",
                )
            with other_connection.cursor() as cursor:
                cursor.execute(create_sql % "MyISAM")
                self.assertEqual(
                    other_connection.introspection.get_storage_engine(
                        cursor, table_name
                    ),
                    "MyISAM",
                )
        finally:
            with default_connection.cursor() as cursor:
                cursor.execute(drop_sql)
            with other_connection.cursor() as cursor:
                cursor.execute(drop_sql)