<?php

namespace fast;

/**
 * 随机生成类
 */
class Random
{

 /**
 * 生成数字和字母
 *
 * @param int $len 长度
 * @return string
 */
 public static function alnum($len = 6)
 {
 return self::build('alnum', $len);
 }

 /**
 * 仅生成字符
 *
 * @param int $len 长度
 * @return string
 */
 public static function alpha($len = 6)
 {
 return self::build('alpha', $len);
 }

 /**
 * 生成指定长度的随机数字
 *
 * @param int $len 长度
 * @return string
 */
 public static function numeric($len = 4)
 {
 return self::build('numeric', $len);
 }

 /**
 * 生成指定长度的无0随机数字
 *
 * @param int $len 长度
 * @return string
 */
 public static function nozero($len = 4)
 {
 return self::build('nozero', $len);
 }

 /**
 * 能用的随机数生成
 * @param string $type 类型 alpha/alnum/numeric/nozero/unique/md5/encrypt/sha1
 * @param int $len 长度
 * @return string
 */
 public static function build($type = 'alnum', $len = 8)
 {
 switch ($type) {
 case 'alpha':
 case 'alnum':
 case 'numeric':
 case 'nozero':
 switch ($type) {
 case 'alpha':
 $pool = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
 break;
 case 'alnum':
 $pool = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
 break;
 case 'numeric':
 $pool = '0123456789';
 break;
 case 'nozero':
 $pool = '123456789';
 break;
 }
 return substr(str_shuffle(str_repeat($pool, ceil($len / strlen($pool)))), 0, $len);
 case 'unique':
 case 'md5':
 return md5(uniqid(mt_rand()));
 case 'encrypt':
 case 'sha1':
 return sha1(uniqid(mt_rand(), true));
 }
 }

 /**
 * 获取全球唯一标识
 * @return string
 */
 public static function uuid()
 {
 return sprintf(
 '%04x%04x-%04x-%04x-%04x-%04x%04x%04x',
 mt_rand(0, 0xffff),
 mt_rand(0, 0xffff),
 mt_rand(0, 0xffff),
 mt_rand(0, 0x0fff) | 0x4000,
 mt_rand(0, 0x3fff) | 0x8000,
 mt_rand(0, 0xffff),
 mt_rand(0, 0xffff),
 mt_rand(0, 0xffff)
 );
 }
}