<?php
namespace App\Utils;
/**
 * 随机生成类
 */
class Random
{
    /**
     * 生成随机字符串，数字，大小写字母随机组合
     *
     * @param int $length  长度
     * @param int $type    类型，1 纯数字，2 纯小写字母，3 纯大写字母，4 数字和小写字母，5 数字和大写字母，6 大小写字母，7 数字和大小写字母
     */
    public static function str_random($length = 6, $type = 1)
    {
        // 取字符集数组
        $number = range(0, 9);
        $lowerLetter = range('a', 'z');
        $upperLetter = range('A', 'Z');
        // 根据type合并字符集
        if ($type == 1) {
            $charset = $number;
        } elseif ($type == 2) {
            $charset = $lowerLetter;
        } elseif ($type == 3) {
            $charset = $upperLetter;
        } elseif ($type == 4) {
            $charset = array_merge($number, $lowerLetter);
        } elseif ($type == 5) {
            $charset = array_merge($number, $upperLetter);
        } elseif ($type == 6) {
            $charset = array_merge($lowerLetter, $upperLetter);
        } elseif ($type == 7) {
            $charset = array_merge($number, $lowerLetter, $upperLetter);
        } else {
            $charset = $number;
        }
        $str = '';
        // 生成字符串
        for ($i = 0; $i < $length; $i++) {
            $str .= $charset[mt_rand(0, count($charset) - 1)];
            // 验证规则
            if ($type == 4 && strlen($str) >= 2) {
                if (!preg_match('/\d+/', $str) || !preg_match('/[a-z]+/', $str)) {
                    $str = substr($str, 0, -1);
                    $i = $i - 1;
                }
            }
            if ($type == 5 && strlen($str) >= 2) {
                if (!preg_match('/\d+/', $str) || !preg_match('/[A-Z]+/', $str)) {
                    $str = substr($str, 0, -1);
                    $i = $i - 1;
                }
            }
            if ($type == 6 && strlen($str) >= 2) {
                if (!preg_match('/[a-z]+/', $str) || !preg_match('/[A-Z]+/', $str)) {
                    $str = substr($str, 0, -1);
                    $i = $i - 1;
                }
            }
            if ($type == 7 && strlen($str) >= 3) {
                if (!preg_match('/\d+/', $str) || !preg_match('/[a-z]+/', $str) || !preg_match('/[A-Z]+/', $str)) {
                    $str = substr($str, 0, -2);
                    $i = $i - 2;
                }
            }
        }
        return $str;
    }
}