<?php
/**
 * Author: cfn <cfn@leapy.cn>
 */

namespace App\Utils;

class Str
{
    /**
     * 获取UUID
     * @param string $prefix
     * @return string
     */
    static function uuid(string $prefix = ''): string
    {
        $chars = md5(uniqid(mt_rand(), true));
        $uuid = substr($chars, 0, 8) . '-';
        $uuid .= substr($chars, 8, 4) . '-';
        $uuid .= substr($chars, 12, 4) . '-';
        $uuid .= substr($chars, 16, 4) . '-';
        $uuid .= substr($chars, 20, 12);
        return $prefix . $uuid;
    }

    /**
     * 获取随机字符串
     * @param int $num
     * @param string $prefix
     * @return string
     */
    static function randStr(int $num, string $prefix = ""): string
    {
        $str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
        $_str = "";
        while ($num > 0) {
            $_str .= substr($str, rand(0, strlen($str) - 1), 1);
            $num--;
        }
        return $prefix . $_str;
    }

}