PHP Decode

class wzkakao {
    
    private $client_id;
    private $state;
    public $access_token;
	public $refresh_token;
	public $expires_in;

    public function __construct($client_id='') {

        $this->client_id = $client_id;
    }
    
    function set_state() {

        $mt     = microtime();
        $rand   = mt_rand();
        $state  = md5($mt . $rand);

        set_session('ss_kakao_state', $state);

        return $state;
    }

    function check_state($state) {

        $ss_state = get_session('ss_kakao_state');

        set_session('ss_kakao_state', '');

        if(!$ss_state || !$state)
            return false;

        return ($ss_state == $state);
    }

    //  :       .
    function get_oauth_authorize_url() {

        $this->state    = $this->set_state();
        $redirect_uri   = urlencode(urldecode(WZ_KAKAO_CALLBACK_URL));

        return 'https://kauth.kakao.com/oauth/authorize?client_id='.$this->client_id.'&response_type=code&redirect_uri='.$redirect_uri.'&state='.$this->state;
    }

    //  
    function get_oauth_authorize_result($code) {
        
        $data = array();
        $data['grant_type']     = 'authorization_code';
        $data['client_id']      = $this->client_id;
        $data['redirect_uri']   = WZ_KAKAO_CALLBACK_URL;
        $data['code']           = $code;
        $data = http_build_query($data);
        
        $result = $this->get_curl('https://kauth.kakao.com/oauth/token', $data, '');

        if ($result) { 
            $json = json_decode($result);
            $this->access_token  = $json->access_token;
            $this->refresh_token = $json->refresh_token;
            $this->expires_in    = $json->expires_in;
            return true;
        } 
        else
            return false;

    }
    
    //       
    function get_user_auth() {

        $data = array();
        $data['Authorization'] = 'Bearer '.$this->access_token;
        $headers = array('Authorization: '.$data['Authorization']);

        return $this->get_curl('https://kapi.kakao.com/v1/user/access_token_info', $data, $headers);
    }

    //  
    function get_user_info() {

        $data = array();
        $data['Authorization'] = 'Bearer '.$this->access_token;
        $headers = array('Authorization: '.$data['Authorization']);

        return $this->get_curl('https://kapi.kakao.com/v1/user/me', $data, $headers);
    }
    
    //  
    function set_user_unlink() {

        $data = array();
        $data['Authorization'] = 'Bearer '.$this->access_token;
        $headers = array('Authorization: '.$data['Authorization']);
        
        return $this->get_curl('https://kapi.kakao.com/v1/user/unlink', '', $headers);
    }

    //  
    function get_refresh_token($app_key, $token) {

        $this->wz_verification();
        
        $data = array();
        $data['grant_type']     = 'refresh_token';
        $data['client_id']      = $app_key;
        $data['refresh_token']  = $token;
        $data = http_build_query($data);

        $result = $this->get_curl('https://kauth.kakao.com/oauth/token', $data, '');
        return $result;
    }

    function get_curl($url, $posts='', $headers='') {

        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $url);
        curl_setopt($curl, CURLOPT_VERBOSE, true);
        curl_setopt($curl, CURLOPT_HEADER, false);

        if ($headers) {
            curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
        }

        if ($posts) {
            curl_setopt($curl, CURLOPT_POST, true); 
            curl_setopt($curl, CURLOPT_POSTFIELDS, $posts);
        }

        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); 
        //curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, true); // true    .
        curl_setopt($curl, CURLOPT_SSLVERSION, true); // SSL  (https  )
        $result = curl_exec($curl); 
        curl_close($curl);

        return $result;
    }

    //  
    function wz_verification() { 
        
        $url = 'http://www.wetoz.kr/connect/verification.php';
        
        $posts = array();
        $posts['ps_domain'] = $_SERVER['SERVER_NAME'];
        $posts['ps_pcode']  = 'kakaoMyAlert';

        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $url);
        curl_setopt($curl, CURLOPT_VERBOSE, true);
        curl_setopt($curl, CURLOPT_HEADER, false);
        curl_setopt($curl, CURLOPT_POST, true); 
        curl_setopt($curl, CURLOPT_POSTFIELDS, $posts);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); 
        $result = curl_exec($curl); 
        curl_close($curl);

        if (substr($result, 0, 5) == 'error') { 
            die(substr($result, 6));
        } 
    }

}