package main

import (
	"fmt"
	"time"
)

func main() {
	s := "2023-12-30"
	//4BC6 [4,11,12,6]
	t, err := time.Parse("2006-01-02", s)
	if err != nil {
		fmt.Println(err)
		return
	}
	y := Uint2BCD(uint64(t.Year()), true)
	fmt.Println("year:", y)
	m := Uint2BCD(uint64(t.Month()), true)
	fmt.Println("mouth:", m)
	d := Uint2BCD(uint64(t.Day()), true)
	fmt.Println("day:", d)
}

func Uint2BCD(n uint64, isBigEndian bool) []byte {
	var b []byte
	//if n < 256 {
	//	b = []byte{0}
	//}
	for i := 0; ; i++ {
		h := (n / 10) % 10
		l := n % 10
		b = append(b, byte(h<<4|l))
		n = n / 100
		if n == 0 {
			break
		}
	}
	if !isBigEndian {
		return b
	}
	l := len(b)
	var r = make([]byte, l)
	for i, v := range b {
		r[l-1-i] = v
	}
	return r
}