<?php
namespace douyin;

class order{

    public function getByteAuthorization($data, $appId,$privateKeyStr, $keyVersion = "1", $nonceStr = '', $timestamp = '') {

        if(!$timestamp){
            $timestamp = time();
        }

        if(!$nonceStr){
            $nonceStr = $this->randStr(10);
        }

        // 读取私钥
        $privateKey = openssl_pkey_get_private($privateKeyStr);
        if (!$privateKey) {
            throw new InvalidArgumentException("Invalid private key");
        }
        // 生成签名
        $signature = $this->getSignature("POST", "/requestOrder", $timestamp, $nonceStr, json_encode($data), $privateKey);
        if ($signature === false) {
            return null;
        }
        // 构造 byteAuthorization
        $byteAuthorization = sprintf("SHA256-RSA2048 appid=%s,nonce_str=%s,timestamp=%s,key_version=%s,signature=%s", $appId, $nonceStr, $timestamp, $keyVersion, $signature);
        return $byteAuthorization;
    }

    /**
     * 获取签名
     * @param $method
     * @param $url
     * @param $timestamp
     * @param $nonce
     * @param $data
     * @param $privateKey
     * @return string
     */
    public function getSignature($method, $url, $timestamp, $nonce, $data, $privateKey) {
        $targetStr = $method. "\n" . $url. "\n" . $timestamp. "\n" . $nonce. "\n" . $data. "\n";
        openssl_sign($targetStr, $sign, $privateKey, OPENSSL_ALGO_SHA256);
        $sign = base64_encode($sign);
        return $sign;
    }

    public function randStr($length = 8) {
        $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
        $str = '';
        for ($i = 0; $i < $length; $i++) {
            $str .= $chars[mt_rand(0, strlen($chars) - 1)];
        }
        return $str;
    }
}
?>