import (
	"database/sql"
	"database/sql/driver"
	"go/ast"
	"reflect"
)

// Expression expression interface
type Expression interface {
	Build(builder Builder)
}

// NegationExpressionBuilder negation expression builder
type NegationExpressionBuilder interface {
	NegationBuild(builder Builder)
}

// Expr raw expression
type Expr struct {
	SQL                string
	Vars               []interface{}

	// ErrMissingWhereClause missing where clause
	ErrMissingWhereClause = errors.New("WHERE conditions required")
	// ErrUnsupportedRelation unsupported relations
	ErrUnsupportedRelation = errors.New("unsupported relations")
	// ErrPrimaryKeyRequired primary keys required
	ErrPrimaryKeyRequired = errors.New("primary key required")
	// ErrModelValueRequired model value required

	err = stmt.Parse(joinTable)
	if err != nil {
		return err
	}
	joinSchema = stmt.Schema

	relation, ok := modelSchema.Relationships.Relations[field]
	isRelation := ok && relation.JoinTable != nil
	if !isRelation {
		return fmt.Errorf("failed to find relation: %s", field)
	}

	for _, ref := range relation.References {
		f := joinSchema.LookUpField(ref.ForeignKey.DBName)
		if f == nil {

	t := tag.Get("gorm")
	if strings.Contains(t, value) {
		return tag
	}
	return reflect.StructTag(fmt.Sprintf(`gorm:"%s;%s"`, value, t))
}

// GetRelationsValues get relations's values from a reflect value
func GetRelationsValues(ctx context.Context, reflectValue reflect.Value, rels []*Relationship) (reflectResults reflect.Value) {
	for _, rel := range rels {

			notRestricted = result
			for _, dbName := range stmt.Schema.DBNames {
				results[dbName] = result
			}
		} else if column == clause.Associations {
			for _, rel := range stmt.Schema.Relationships.Relations {
				results[rel.Name] = result
			}
		} else if field := stmt.Schema.LookUpField(column); field != nil && field.DBName != "" {
			results[field.DBName] = result

		ModelType:        modelType,
		Table:            tableName,
		FieldsByName:     map[string]*Field{},
		FieldsByBindName: map[string]*Field{},
		FieldsByDBName:   map[string]*Field{},
		Relationships:    Relationships{Relations: map[string]*Relationship{}},
		cacheStore:       cacheStore,
		namer:            namer,
		initialized:      make(chan struct{}),
	}
	// When the schema initialization is completed, the channel will be closed