<?php
/*
 * @link       http://www.apoyl.com/
 * @since      1.0.0
 * @package    Apoyl_Weixinshare
 * @subpackage Apoyl_Weixinshare/public/weixinapi
 * @author     凹凸曼 <jar-c@163.com>
 *
 */
class ApoylJSSDK
{

    private $appId;

    private $appSecret;

    private $openbs;

    public function __construct($appId, $appSecret)
    {
        $this->openbs = false;
        $this->appId = $appId;
        $this->appSecret = $appSecret;
    }

    public function getSignPackage()
    {
        $jsapiTicket = $this->getJsApiTicket();
        
        // 注意 URL 一定要动态获取，不能 hardcode.
        $protocol = (! empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
        $url = "$protocol$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
        
        $timestamp = time();
        $nonceStr = $this->createNonceStr();
        
        // 这里参数的顺序要按照 key 值 ASCII 码升序排序
        $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr&timestamp=$timestamp&url=$url";
        
        $signature = sha1($string);
        
        $signPackage = array(
            "appId" => $this->appId,
            "nonceStr" => $nonceStr,
            "timestamp" => $timestamp,
            "url" => $url,
            "signature" => $signature,
            "rawString" => $string
        );
        return $signPackage;
    }

    private function createNonceStr($length = 16)
    {
        $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        $str = "";
        for ($i = 0; $i < $length; $i ++) {
            $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
        }
        return $str;
    }

    private function getJsApiTicket()
    {
    
        $data = json_decode($this->get_php_file("jsapi_ticket.php"));
        if ($data->expire_time < time()) {
            $accessToken = $this->getAccessToken();
            // 如果是企业号用以下 URL 获取 ticket
            if ($this->openbs)
                $url = "https://qyapi.weixin.qq.com/cgi-bin/get_jsapi_ticket?access_token=$accessToken";
            else
                $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";
            $res = json_decode($this->httpGet($url));
            
            $ticket = $res->ticket;
            if ($ticket) {
                $data = new stdClass();
                $data->expire_time = time() + 7000;
                $data->jsapi_ticket = $ticket;
                $this->set_php_file("jsapi_ticket.php", json_encode($data));
            }
        } else {
            $ticket = $data->jsapi_ticket;
        }
        
        return $ticket;
    }

    private function getAccessToken()
    {
     
        $data = json_decode($this->get_php_file("access_token.php"));
        if ($data->expire_time < time()) {
            // 如果是企业号用以下URL获取access_token
            if ($this->openbs)
                $url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid=$this->appId&corpsecret=$this->appSecret";
            else
                $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";
            $res = json_decode($this->httpGet($url));
            
            $access_token = $res->access_token;
            if ($access_token) {
                $data = new stdClass();
                $data->expire_time = time() + 7000;
                $data->access_token = $access_token;
                $this->set_php_file("access_token.php", json_encode($data));
            }
        } else {
            $access_token = $data->access_token;
        }
        return $access_token;
    }

    private function httpGet($url)
    {
        $res = wp_remote_retrieve_body(wp_remote_get($url, array(
            'timeout' => 120
        )));
        return $res;
    }

    private function get_php_file($filename)
    {
        $filefull = plugin_dir_path(dirname(__FILE__)) . 'cache/' . $filename;
        if (! file_exists($filefull))
            return '';
        $fp = fopen($filefull, 'r');
        $re = fread($fp, filesize($filefull));
        return trim(substr($re, 15));
    }

    private function set_php_file($filename, $content)
    {
        $filefull = plugin_dir_path(dirname(__FILE__)) . 'cache/' . $filename;
        
        $fp = fopen($filefull, "w");
        fwrite($fp, "<?php exit();?>" . $content);
        fclose($fp);
    }
}