package dts

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

type NullDate struct {
	Date  time.Time
	Valid bool // Valid is true if Date is not NULL
}

func (date NullDate) Any() any {
	if date.Valid {
		return date.Date
	}
	return nil
}

func (nd *NullDate) Scan(value any) error {
	if value == nil {
		nd.Date, nd.Valid = time.Time{}, false
		return nil
	}
	nt := new(sql.NullTime)
	err := nt.Scan(value)
	nd.Date = nt.Time
	nd.Valid = nt.Valid
	return err
}

func (nd NullDate) Value() (driver.Value, error) {
	if !nd.Valid {
		return nil, nil
	}
	y, m, d := nd.Date.Date()
	return time.Date(y, m, d, 0, 0, 0, 0, nd.Date.Location()), nil
}

// GormDataType gorm common data type
func (nd NullDate) GormDataType() string {
	return "date"
}

func (nd NullDate) MarshalJSON() ([]byte, error) {
	if nd.Valid {
		return nd.Date.MarshalJSON()
	}
	return json.Marshal(nil)
}

func (nd *NullDate) UnmarshalJSON(b []byte) error {
	if string(b) == "null" {
		nd.Valid = false
		return nil
	}
	err := nd.Date.UnmarshalJSON(b)
	if err == nil {
		nd.Valid = true
	}
	return err
}