<?php
namespace App\Service;

/**
 * PHP7.1及其之上版本的回调加解密类库
 * 该版本依赖openssl_encrypt方法加解密，注意版本依赖 (PHP 5 >= 5.3.0, PHP 7)
 */
class DingCallbackCrypto
{
    /**
     * @param token          钉钉开放平台上，开发者设置的token
     * @param encodingAesKey 钉钉开放台上，开发者设置的EncodingAESKey
     * @param corpId         企业自建应用-事件订阅, 使用appKey
     *                       企业自建应用-注册回调地址, 使用corpId
     *                       第三方企业应用, 使用suiteKey
     */
    private $m_token;
    private $m_encodingAesKey;
    private $m_corpId;
    //注意这里修改为构造函数
    function __construct($token, $encodingAesKey, $ownerKey)
    {
        $this->m_token = $token;
        $this->m_encodingAesKey = $encodingAesKey;
        $this->m_corpId = $ownerKey;
    }

    public function getEncryptedMap($plain){
        $timeStamp = time();
        $pc = new Prpcrypt($this->m_encodingAesKey);
        $nonce= $pc->getRandomStr();
        return $this->getEncryptedMapDetail($plain, $timeStamp, $nonce);
    }

    /**
     * 加密回调信息
     */
    public function getEncryptedMapDetail($plain, $timeStamp, $nonce)
    {
        $pc = new Prpcrypt($this->m_encodingAesKey);

        $array = $pc->encrypt($plain, $this->m_corpId);
        $ret = $array[0];
        if ($ret != 0) {
            //return $ret;
            // return ['ErrorCode'=>$ret, 'data' => ''];
            throw new \Exception('AES加密错误',ErrorCode::$EncryptAESError);
        }

        if ($timeStamp == null) {
            $timeStamp = time();
        }
        $encrypt = $array[1];

        $sha1 = new SHA1;
        $array = $sha1->getSHA1($this->m_token, $timeStamp, $nonce, $encrypt);
        $ret = $array[0];
        if ($ret != 0) {
            //return $ret;
            throw new \Exception('ComputeSignatureError',ErrorCode::$ComputeSignatureError);
        }
        $signature = $array[1];

        $encryptMsg = json_encode(array(
            "msg_signature" => $signature,
            "encrypt" => $encrypt,
            "timeStamp" => $timeStamp,
            "nonce" => $nonce
        ));

        return $encryptMsg;
    }

    /**
     * 解密回调信息
     */
    public function getDecryptMsg($signature, $timeStamp = null, $nonce, $encrypt)
    {
        if (strlen($this->m_encodingAesKey) != 43) {
            //return ErrorCode::$IllegalAesKey;
            // return ['ErrorCode'=>ErrorCode::$IllegalAesKey, 'data' => ''];
            throw new \Exception('IllegalAesKey',ErrorCode::$IllegalAesKey);
        }

        $pc = new Prpcrypt($this->m_encodingAesKey);

        if ($timeStamp == null) {
            $timeStamp = time();
        }

        $sha1 = new SHA1;
        $array = $sha1->getSHA1($this->m_token, $timeStamp, $nonce, $encrypt);
        $ret = $array[0];

        if ($ret != 0) {
            //return $ret;
            // return ['ErrorCode'=>$ret, 'data' => ''];
            throw new \Exception('ComputeSignatureError',ErrorCode::$ComputeSignatureError);
        }

        $verifySignature = $array[1];
        if ($verifySignature != $signature) {
            //return ErrorCode::$ValidateSignatureError;
            //return ['ErrorCode'=>ErrorCode::$ValidateSignatureError, 'data' => ''];
            throw new \Exception('ValidateSignatureError',ErrorCode::$ValidateSignatureError);
        }

        $result = $pc->decrypt($encrypt, $this->m_corpId);

        if ($result[0] != 0) {
            //return $result[0];
            // return ['ErrorCode'=>$result[0], 'data' => ''];
            throw new \Exception('DecryptAESError',ErrorCode::$DecryptAESError);
        }
        $decryptMsg = $result[1];
        //return ErrorCode::$OK;
        return $decryptMsg;

    }
}

class SHA1
{
    public function getSHA1($token, $timestamp, $nonce, $encrypt_msg)
    {
        try {
            $array = array($encrypt_msg, $token, $timestamp, $nonce);
            sort($array, SORT_STRING);
            $str = implode($array);
            return array(ErrorCode::$OK, sha1($str));
        } catch (\Exception $e) {
            print $e . "\n";
            return array(ErrorCode::$ComputeSignatureError, null);
        }
    }

}

/**
 * error code 说明.
 * <ul>
 *    <li>-900004: encodingAesKey 非法</li>
 *    <li>-900005: 签名验证错误</li>
 *    <li>-900006: sha加密生成签名失败</li>
 *    <li>-900007: aes 加密失败</li>
 *    <li>-900008: aes 解密失败</li>
 *    <li>-900010: suiteKey 校验错误</li>
 * </ul>
 */
class ErrorCode
{
    public static $OK = 0;

    public static $IllegalAesKey = 900004;
    public static $ValidateSignatureError = 900005;
    public static $ComputeSignatureError = 900006;
    public static $EncryptAESError = 900007;
    public static $DecryptAESError = 900008;
    public static $ValidateSuiteKeyError = 900010;
}

class PKCS7Encoder
{
    public static $block_size = 32;

    function encode($text)
    {
        $block_size = PKCS7Encoder::$block_size;
        $text_length = strlen($text);
        $amount_to_pad = PKCS7Encoder::$block_size - ($text_length % PKCS7Encoder::$block_size);
        if ($amount_to_pad == 0) {
            $amount_to_pad = PKCS7Encoder::$block_size;
        }
        $pad_chr = chr($amount_to_pad);
        $tmp = "";
        for ($index = 0; $index < $amount_to_pad; $index++) {
            $tmp .= $pad_chr;
        }
        return $text . $tmp;
    }

    function decode($text)
    {
        $pad = ord(substr($text, -1));
        if ($pad < 1 || $pad > PKCS7Encoder::$block_size) {
            $pad = 0;
        }
        return substr($text, 0, (strlen($text) - $pad));
    }

}

class Prpcrypt
{
    public $key;

    function __construct($k)
    {
        $this->key = base64_decode($k . "=");
    }

    public function encrypt($text, $corpid)
    {

        try {
            //获得16位随机字符串，填充到明文之前
            $random = $this->getRandomStr();
            $text = $random . pack("N", strlen($text)) . $text . $corpid;
            $iv = substr($this->key, 0, 16);

            // 网络字节序
            // $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
            // $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');

            //使用自定义的填充方式对明文进行补位填充
            $pkc_encoder = new PKCS7Encoder;
            $text = $pkc_encoder->encode($text);
            // mcrypt_generic_init($module, $this->key, $iv);
            // //加密
            // $encrypted = mcrypt_generic($module, $text);
            // mcrypt_generic_deinit($module);
            // mcrypt_module_close($module);


            $encrypted = openssl_encrypt($text, 'AES-256-CBC', $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv );

            //print(base64_encode($encrypted));
            //使用BASE64对加密后的字符串进行编码
            return array(ErrorCode::$OK, base64_encode($encrypted));
        } catch (\Exception $e) {
            print $e;
            return array(ErrorCode::$EncryptAESError, null);
        }
    }

    public function decrypt($encrypted, $corpid)
    {

        try {
            $ciphertext_dec = base64_decode($encrypted);
            // $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
            $iv = substr($this->key, 0, 16);
            // mcrypt_generic_init($module, $this->key, $iv);

            // $decrypted = mdecrypt_generic($module, $ciphertext_dec);
            // mcrypt_generic_deinit($module);
            // mcrypt_module_close($module);

            $decrypted = openssl_decrypt ( $ciphertext_dec, 'AES-256-CBC', $this->key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv );


            // return $decrypted;
        } catch (\Exception $e) {
            return array(ErrorCode::$DecryptAESError, null);
        }


        try {
            //去除补位字符
            $pkc_encoder = new PKCS7Encoder;
            $result = $pkc_encoder->decode($decrypted);
            //去除16位随机字符串,网络字节序和AppId
            if (strlen($result) < 16)
                return "";
            $content = substr($result, 16, strlen($result));
            $len_list = unpack("N", substr($content, 0, 4));
            $xml_len = $len_list[1];
            $xml_content = substr($content, 4, $xml_len);
            $from_corpid = substr($content, $xml_len + 4);
        } catch (\Exception $e) {
            print $e;
            return array(ErrorCode::$DecryptAESError, null);
        }
        if ($from_corpid != $corpid)
            return array(ErrorCode::$ValidateSuiteKeyError, null);


        return array(0, $xml_content);

    }

    function getRandomStr()
    {

        $str = "";
        $str_pol = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvwxyz";
        $max = strlen($str_pol) - 1;
        for ($i = 0; $i < 16; $i++) {
            $str .= $str_pol[mt_rand(0, $max)];
        }
        return $str;
    }
}


///**
// * 以下为开发者需要自行构造的接口(也就是回调url)，接口内调用demo类中的解密和加密方法即可
// */
//
//function test_demo(){
//    // 构造加解密方法
//    $crypt = new DingCallbackCrypto("token", "aes_key", "ownerKey");
//    // 解密方法； data为钉钉服务器请求开发者该接口时携带的参数(msg_signature,timeStamp和nonce在request中，encrypt在body中)
//    $text = $crypt->getDecryptMsg($data->msg_signature, $data->timeStamp, $data->nonce, $data->encrypt);
//    var_dump($text);
//    // 加密返回；参数固定传success字符串，该方法得到的信息直接返回给钉钉服务器即可
//    $res = $crypt->getEncryptedMap("success");
//    var_dump($res);
//}
//
//test_demo();