package utils

import (
	"bytes"
	"crypto/rand"
	"math/big"
)

func RandomString(len int) string {
	return RandomStringRange(len, "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890")
}

func RandomStringRange(len int, str string) string {
	var res string
	b := bytes.NewBufferString(str)
	length := b.Len()
	bigInt := big.NewInt(int64(length))
	for i := 0; i < len; i++ {
		randomInt, _ := rand.Int(rand.Reader, bigInt)
		res += string(str[randomInt.Int64()])
	}
	return res
}