package schema

import (
	"reflect"
	"sync"
)

// sync pools
var (
	normalPool      sync.Map
	poolInitializer = func(reflectType reflect.Type) FieldNewValuePool {
		v, _ := normalPool.LoadOrStore(reflectType, &sync.Pool{
			New: func() interface{} {
				return reflect.New(reflectType).Interface()
			},
		})
		return v.(FieldNewValuePool)
	}

type Session struct {
	DryRun                   bool
	PrepareStmt              bool
	NewDB                    bool
	Initialized              bool
	SkipHooks                bool
	SkipDefaultTransaction   bool
	DisableNestedTransaction bool
	AllowGlobalUpdate        bool
	FullSaveAssociations     bool
	QueryFields              bool
	Context                  context.Context

	ColumnType() (columnType string, ok bool) // varchar(64)
	PrimaryKey() (isPrimaryKey bool, ok bool)
	AutoIncrement() (isAutoIncrement bool, ok bool)
	Length() (length int64, ok bool)
	DecimalSize() (precision int64, scale int64, ok bool)
	Nullable() (nullable bool, ok bool)
	Unique() (unique bool, ok bool)
	ScanType() reflect.Type
	Comment() (value string, ok bool)
	DefaultValue() (value string, ok bool)
}

	deleteClauses = []string{"DELETE", "FROM", "WHERE"}
)

type Config struct {
	LastInsertIDReversed bool
	CreateClauses        []string
	QueryClauses         []string
	UpdateClauses        []string
	DeleteClauses        []string
}

func RegisterDefaultCallbacks(db *gorm.DB, config *Config) {
	enableTransaction := func(db *gorm.DB) bool {
		return !db.SkipDefaultTransaction
	}

	if len(config.CreateClauses) == 0 {

		Name string `gorm:"unique"`
	}

	db, err := OpenTestConnection(&gorm.Config{TranslateError: true})
	if err != nil {
		t.Fatalf("failed to connect database, got error %v", err)
	}

	dialectors := map[string]bool{"sqlite": true, "postgres": true, "mysql": true, "sqlserver": true}
	if supported, found := dialectors[db.Dialector.Name()]; !(found && supported) {
		return
	}

	DB.Migrator().DropTable(&City{})

	"gorm.io/gorm/utils"
)

func BeforeDelete(db *gorm.DB) {
	if db.Error == nil && db.Statement.Schema != nil && !db.Statement.SkipHooks && db.Statement.Schema.BeforeDelete {
		callMethod(db, func(value interface{}, tx *gorm.DB) bool {
			if i, ok := value.(BeforeDeleteInterface); ok {
				db.AddError(i.BeforeDelete(tx))
				return true
			}

			return false
		})
	}
}

func DeleteBeforeAssociations(db *gorm.DB) {

				}
			}

			specifiedRelationsName := make(map[string]interface{})
			for _, join := range db.Statement.Joins {
				if db.Statement.Schema != nil {
					var isRelations bool // is relations or raw sql
					var relations []*schema.Relationship
					relation, ok := db.Statement.Schema.Relationships.Relations[join.Name]
					if ok {
						isRelations = true

			Manager: &User{
				Name: "Alexis Manager",
				Tools: []Tools{
					{Name: "Alexis Tool 1"},
					{Name: "Alexis Tool 2"},
				},
			},
		},
		{
			Name: "TestMergeNestedPreloadWithNestedJoin-2",
			Manager: &User{
				Name: "Jinzhu Manager",
				Tools: []Tools{
					{Name: "Jinzhu Tool 1"},
					{Name: "Jinzhu Tool 2"},
				},
			},
		},
	}

	DB.Create(&users)

	}
	Scan(rows, tx, ScanInitialized)
	return tx.Error
}

// Connection uses a db connection to execute an arbitrary number of commands in fc. When finished, the connection is
// returned to the connection pool.
func (db *DB) Connection(fc func(tx *DB) error) (err error) {
	if db.Error != nil {
		return db.Error
	}

	tx := db.getInstance()
	sqlDB, err := tx.DB()
	if err != nil {
		return
	}

type Polymorphic struct {
	PolymorphicID   *Field
	PolymorphicType *Field
	Value           string
}

type Reference struct {
	PrimaryKey    *Field
	PrimaryValue  string
	ForeignKey    *Field
	OwnPrimaryKey bool
}

func (schema *Schema) parseRelation(field *Field) *Relationship {
	var (
		err        error
		fieldValue = reflect.New(field.IndirectFieldType).Interface()
		relation   = &Relationship{