package dts

import (
	"database/sql"
	"database/sql/driver"
	"encoding/json"
)

type NullString sql.NullString

// Scan implements the [Scanner] interface.
func (ns *NullString) Scan(value any) error {
	ss := new(sql.NullString)
	err := ss.Scan(value)
	ns.String = ss.String
	ns.Valid = ss.Valid
	return err
}

// Value implements the [driver.Valuer] interface.
func (ns NullString) Value() (driver.Value, error) {
	if !ns.Valid {
		return nil, nil
	}
	return ns.String, nil
}

func (ns NullString) MarshalJSON() ([]byte, error) {
	if ns.Valid {
		return json.Marshal(ns.String)
	}
	return json.Marshal(nil)
}

func (ns *NullString) UnmarshalJSON(b []byte) error {
	if string(b) == "null" {
		ns.Valid = false
		return nil
	}
	err := json.Unmarshal(b, &ns.String)
	if err == nil {
		ns.Valid = true
	}
	return err
}