/**
 * QQ互联 oauth
 * @author dyllen
 *
 */
class Oauth
{
  //取Authorization Code Url
  const PC_CODE_URL = 'https://graph.qq.com/oauth2.0/authorize';
   
  //取Access Token Url
  const PC_ACCESS_TOKEN_URL = 'https://graph.qq.com/oauth2.0/token';
   
  //取用户 Open Id Url
  const OPEN_ID_URL = 'https://graph.qq.com/oauth2.0/me';
   
  //用户授权之后的回调地址
  public $redirectUri = null;
   
  // App Id
  public $appid = null;
   
  //App Key
  public $appKey = null;
   
  //授权列表
  //字符串，多个用逗号隔开
  public $scope = null;
   
  //授权code
  public $code = null;
   
  //续期access token的凭证
  public $refreshToken = null;
   
  //access token
  public $accessToken = null;
   
  //access token 有效期，单位秒
  public $expiresIn = null;
   
  //state
  public $state = null;
   
  public $openid = null;
   
  //construct
  public function __construct($config=[])
  {
    foreach($config as $key => $value) {
      $this->$key = $value;
    }
  }
   
  /**
   * 得到获取Code的url
   * @throws \InvalidArgumentException
   * @return string
   */
  public function codeUrl()
  {
    if (!$this->redirectUri) {
      throw new \Exception('parameter $redirectUri must be set.');
    }
    $query = [
        'response_type' => 'code',
        'client_id' => $this->appid,
        'redirect_uri' => $this->redirectUri,
        'state' => $this->getState(),
        'scope' => $this->scope,
    ];
   
    return self::PC_CODE_URL . '?' . http_build_query($query);
  }
   
  /**
   * 取access token
   * @throws Exception
   * @return boolean
   */
  public function getAccessToken()
  {
    $params = [
        'grant_type' => 'authorization_code',
        'client_id' => $this->appid,
        'client_secret' => $this->appKey,
        'code' => $this->code,
        'redirect_uri' => $this->redirectUri,
    ];
   
    $url = self::PC_ACCESS_TOKEN_URL . '?' . http_build_query($params);
    $content = $this->getUrl($url);
    parse_str($content, $res);
    if ( !isset($res['access_token']) ) {
      $this->thrwoError($content);
    }
   
    $this->accessToken = $res['access_token'];
    $this->expiresIn = $res['expires_in'];
    $this->refreshToken = $res['refresh_token'];
   
    return true;
  }
   
  /**
   * 刷新access token
   * @throws Exception
   * @return boolean
   */
  public function refreshToken()
  {
    $params = [
        'grant_type' => 'refresh_token',
        'client_id' => $this->appid,
        'client_secret' => $this->appKey,
        'refresh_token' => $this->refreshToken,
    ];
   
    $url = self::PC_ACCESS_TOKEN_URL . '?' . http_build_query($params);
    $content = $this->getUrl($url);
    parse_str($content, $res);
    if ( !isset($res['access_token']) ) {
      $this->thrwoError($content);
    }
   
    $this->accessToken = $res['access_token'];
    $this->expiresIn = $res['expires_in'];
    $this->refreshToken = $res['refresh_token'];
   
    return true;
  }
   
  /**
   * 取用户open id
   * @return string
   */
  public function getOpenid()
  {
    $params = [
        'access_token' => $this->accessToken,
    ];
   
    $url = self::OPEN_ID_URL . '?' . http_build_query($params);
       
    $this->openid = $this->parseOpenid( $this->getUrl($url) );
     
    return $this->openid;
  }
   
  /**
   * get方式取url内容
   * @param string $url
   * @return mixed
   */
  public function getUrl($url)
  {
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
    curl_setopt($ch, CURLOPT_URL, $url);
    $response = curl_exec($ch);
    curl_close($ch);
   
    return $response;
  }
   
  /**
   * post方式取url内容
   * @param string $url
   * @param array $keysArr
   * @param number $flag
   * @return mixed
   */
  public function postUrl($url, $keysArr, $flag = 0)
  {
    $ch = curl_init();
    if(! $flag) curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
    curl_setopt($ch, CURLOPT_POST, TRUE);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $keysArr);
    curl_setopt($ch, CURLOPT_URL, $url);
    $ret = curl_exec($ch);
   
    curl_close($ch);
    return $ret;
  }
   
   
  /**
   * 取state
   * @return string
   */
  protected function getState()
  {
    $this->state = md5(uniqid(rand(), true));
    //state暂存在缓存里面
    //自己定义
        //。。。。。。。。。
   
    return $this->state;
  }
   
  /**
   * 验证state
   * @return boolean
   */
  protected function verifyState()
  {
    //。。。。。。。
  }
   
  /**
   * 抛出异常
   * @param string $error
   * @throws \Exception
   */
  protected function thrwoError($error)
  {
    $subError = substr($error, strpos($error, "{"));
    $subError = strstr($subError, "}", true) . "}";
    $error = json_decode($subError, true);
     
    throw new \Exception($error['error_description'], (int)$error['error']);
  }
   
  /**
   * 从获取openid接口的返回数据中解析出openid
   * @param string $str
   * @return string
   */
  protected function parseOpenid($str)
  {
    $subStr = substr($str, strpos($str, "{"));
    $subStr = strstr($subStr, "}", true) . "}";
    $strArr = json_decode($subStr, true);
    if(!isset($strArr['openid'])) {
      $this->thrwoError($str);
    }
     
    return $strArr['openid'];
  }
}