package dts

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

type NullUint struct {
	Uint  uint
	Valid bool // Valid is true if Uint is not NULL
}

func NewNullUint(n uint) NullUint {
	return NullUint{
		Uint:  n,
		Valid: n > 0,
	}
}

func (n NullUint) Any() any {
	if n.Valid {
		return n.Uint
	}
	return nil
}

// Scan implements the Scanner interface.
func (n *NullUint) Scan(value any) error {
	if value == nil {
		n.Uint, n.Valid = 0, false
		return nil
	}
	ni := new(sql.NullInt64)
	err := ni.Scan(value)
	if err != nil {
		return err
	}
	if !ni.Valid {
		n.Uint, n.Valid = 0, false
		return nil
	}
	n.Uint = uint(ni.Int64)
	n.Valid = true
	return nil
}

// Value implements the driver Valuer interface.
func (n NullUint) Value() (driver.Value, error) {
	if !n.Valid {
		return nil, nil
	}
	// 注意：driver.Value 不支持 unit
	return int64(n.Uint), nil
}

func (n NullUint) MarshalJSON() ([]byte, error) {
	if n.Valid {
		return json.Marshal(n.Uint)
	}
	return json.Marshal(nil)
}

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