<?php
 
 /**
  * Facebook登录
  * @author wangdong
  * @ctime 2014-07-15
  */
 class FacebookSDK extends ThinkOauth{
     /**
      * 获取requestCode的api接口
      * @var string
      */
     protected $GetRequestCodeURL = 'https://www.facebook.com/dialog/oauth';
 
     /**
      * 获取access_token的api接口
      * @var string
      */
     protected $GetAccessTokenURL = 'https://graph.facebook.com/oauth/access_token';
 
     /**
      * 获取request_code的额外参数 URL查询字符串格式
      * @var srting
      */
     protected $Authorize = 'scope=email';
 
     /**
      * API根路径
      * @var string
      */
     protected $ApiBase = 'https://graph.facebook.com/';
 
     /**
      * 组装接口调用参数 并调用接口
      * @param  string $api    微博API
      * @param  string $param  调用API的额外参数
      * @param  string $method HTTP请求方法 默认为GET
      * @param  bool   $multi
      * @return array
      */
     public function call($api, $param = '', $method = 'GET', $multi = false){
         /*  facebook 调用公共参数 */
         $params = array('access_token'=>$this->Token['access_token']);
         $header = array();
 
         $data = $this->http($this->url($api), $this->param($params, $param), $method, $header);
         return json_decode($data, true);
     }
     
     /**
      * 解析access_token方法请求后的返回值
      * @param string $result 获取access_token的方法的返回值
      * @param mix    $extend
      * @return array
      */
     protected function parseToken($result, $extend){
         parse_str($result, $data);
         if(is_array($data) && $data['access_token'] && $data['expires']){
             $this->Token = $data;
             $data['openid'] = $this->openid();
             return $data;
         }else{
             throw new Exception("获取 facebook ACCESS_TOKEN出错：未知错误");
         }
 
     }
     
     /**
      * 获取当前授权应用的openid
      * @return string
      */
     public function openid(){
         if(isset($this->Token['openid']))
             return $this->Token['openid'];
         
         $data = $this->call('me');
         if(!empty($data['id']))
             return $data['id'];
         else
             throw new Exception('没有获取到 facebook 用户ID！');
     }
     
 }