package format

import (
	"log"
	"strconv"
	"strings"
)

// 数字变成带千分位的字符串
func NumToStringWithThousandthPercentile(numberStr string) string {
	numberStr = strings.TrimLeft(numberStr, "0") //去掉左边开始的0
	if _, err := strconv.ParseFloat(numberStr, 64); err != nil {
		log.Fatalln("is not a number")
		return ""
	}
	sliceList := strings.Split(numberStr, ".") //切分开小数
	s := sliceList[0]
	f := ""
	if len(sliceList) == 2 {
		f = "." + sliceList[1]
	}
	l := len(s)
	if l <= 3 {
		return s + f
	}
	r := l % 3 //前面第几位开始加入千分位
	if r == 0 {
		r = 3
	}
	b := strings.Builder{}
	for i := 0; i < l; i++ {
		b.WriteString(string(s[i]))
		if i+1 == r && i != l-1 {
			b.WriteString(",")
			r += 3
		}
	}
	b.WriteString(f)
	return b.String()
}