<?php

namespace App\Helpers;

use QrCode;

class CDKEY
{

    private static $key = '[$]P&Pom4a9llX7#';

    public static function encode($code)
    {
        $encode = self::authCode($code, 'ENCODE');
        $encode = str_replace('/', '-', $encode);
        return route('index.index') . '/V/' . $encode;
    }

    /**
     * 生成器
     * @Author:<C.Jason>
     * @Date:2018-12-23T12:13:15+0800
     * @return [type] [description]
     */
    public static function generator($code, $format = 'svg', $size = 300)
    {
        $URL = self::encode($code);
        switch ($format) {
            case 'svg':
                $qrcode = QrCode::format('svg')->errorCorrection("L")->size($size)->margin(0)->generate($URL);
                break;
            case 'png':
                $qrcode = 'data:image/png;base64,' . base64_encode(QrCode::format('svg')->errorCorrection("L")->size($size)->margin(0)->generate($URL));
                break;
            default:
                throw new \Exception('非法图片格式');
                break;
        }
        return [
            'url'    => $URL,
            'qrcode' => $qrcode,
        ];
    }

    public static function parse($string): string
    {
        $string = str_replace(' ', '+', $string);
        $string = str_replace('-', '/', $string);

        return self::authCode($string);
    }

    /**
     * 加密方法
     * @Author:<C.Jason>
     * @Date:2018-12-23T12:18:07+0800
     * @param [type] $string 要加密的
     * @param string $operation 操作
     * @param string $key 密钥
     * @param integer $expiry 过期时间
     * @return [type] [description]
     */
    public static function authCode($string, $operation = 'DECODE', $key = '', $expiry = 0): string
    {
        $ckey_length = 4;

        $key  = md5($key ? $key : self::$key);
        $keya = md5(substr($key, 0, 16));
        $keyb = md5(substr($key, 16, 16));
        $keyc = $ckey_length ? ($operation == 'DECODE' ? substr($string, 0, $ckey_length) : substr(md5(microtime()), -$ckey_length)) : '';

        $cryptkey   = $keya . md5($keya . $keyc);
        $key_length = strlen($cryptkey);

        $string        = $operation == 'DECODE' ? base64_decode(substr($string, $ckey_length)) : sprintf('%010d', $expiry ? $expiry + time() : 0) . substr(md5($string . $keyb), 0, 16) . $string;
        $string_length = strlen($string);
        $result        = '';
        $box           = range(0, 255);
        $rndkey        = array();

        for ($i = 0; $i <= 255; $i++) {
            $rndkey[$i] = ord($cryptkey[$i % $key_length]);
        }

        for ($j = $i = 0; $i < 256; $i++) {
            $j       = ($j + $box[$i] + $rndkey[$i]) % 256;
            $tmp     = $box[$i];
            $box[$i] = $box[$j];
            $box[$j] = $tmp;
        }

        for ($a = $j = $i = 0; $i < $string_length; $i++) {
            $a       = ($a + 1) % 256;
            $j       = ($j + $box[$a]) % 256;
            $tmp     = $box[$a];
            $box[$a] = $box[$j];
            $box[$j] = $tmp;
            $result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));
        }
        if ($operation == 'DECODE') {
            if ((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) && substr($result, 10, 16) == substr(md5(substr($result, 26) . $keyb), 0, 16)) {
                return substr($result, 26);
            } else {
                return '';
            }
        } else {
            return $keyc . str_replace('=', '', base64_encode($result));
        }
    }
}