<?php
/*
    方倍工作室
    CopyRight 2013 All Rights Reserved
*/

define("TOKEN", "weixin");

$wechatObj = new wechatCallbackapiTest();
if (!isset($_GET['echostr'])) {
    $wechatObj->responseMsg();
}else{
    $wechatObj->valid();
}

class wechatCallbackapiTest
{
    public function valid()
    {
        $echoStr = $_GET["echostr"];
        if($this->checkSignature()){
            echo $echoStr;
            exit;
        }
    }

    private function checkSignature()
    {
        $signature = $_GET["signature"];
        $timestamp = $_GET["timestamp"];
        $nonce = $_GET["nonce"];
        $token = TOKEN;
        $tmpArr = array($token, $timestamp, $nonce);
        sort($tmpArr);
        $tmpStr = implode($tmpArr);
        $tmpStr = sha1($tmpStr);

        if($tmpStr == $signature){
            return true;
        }else{
            return false;
        }
    }

    public function responseMsg()
    {
        $postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
        if (!empty($postStr)){
            $postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
            $RX_TYPE = trim($postObj->MsgType);

            switch ($RX_TYPE)
            {
                case "text":
                    $resultStr = $this->receiveText($postObj);
                    break;
                case "event":
                    $resultStr = $this->receiveEvent($postObj);
                    break;
                default:
                    $resultStr = "";
                    break;
            }
            echo $resultStr;
        }else {
            echo "";
            exit;
        }
    }

    private function receiveText($object)
    {
        $keyword = trim($object->Content);
        $url = "http://api100.duapp.com/history/?appkey=trialuser";
        $output = file_get_contents($url);
        $contentStr = json_decode($output, true);
        
        if (is_array($contentStr)){
            $resultStr = $this->transmitNews($object, $contentStr);
        }else{
            $resultStr = $this->transmitText($object, $contentStr);
        }
        return $resultStr;
    }

    private function receiveEvent($object)
    {
        $contentStr = "";
        switch ($object->Event)
        {
            case "subscribe":
                $contentStr = "欢迎关注方倍工作室";
                break;
            default:
                break;
        }
        $resultStr = $this->transmitText($object, $contentStr);
        return $resultStr;
    }
    
    private function transmitText($object, $content)
    {
        $textTpl = "<xml>
<ToUserName><![CDATA[%s]]></ToUserName>
<FromUserName><![CDATA[%s]]></FromUserName>
<CreateTime>%s</CreateTime>
<MsgType><![CDATA[text]]></MsgType>
<Content><![CDATA[%s]]></Content>
</xml>";
        $resultStr = sprintf($textTpl, $object->FromUserName, $object->ToUserName, time(), $content);
        return $resultStr;
    }

    private function transmitNews($object, $arr_item)
    {
        if(!is_array($arr_item))
            return;

        $itemTpl = "    <item>
        <Title><![CDATA[%s]]></Title>
        <Description><![CDATA[%s]]></Description>
        <PicUrl><![CDATA[%s]]></PicUrl>
        <Url><![CDATA[%s]]></Url>
    </item>
";
        $item_str = "";
        foreach ($arr_item as $item)
            $item_str .= sprintf($itemTpl, $item['Title'], $item['Description'], $item['PicUrl'], $item['Url']);

        $newsTpl = "<xml>
<ToUserName><![CDATA[%s]]></ToUserName>
<FromUserName><![CDATA[%s]]></FromUserName>
<CreateTime>%s</CreateTime>
<MsgType><![CDATA[news]]></MsgType>
<Content><![CDATA[]]></Content>
<ArticleCount>%s</ArticleCount>
<Articles>
$item_str</Articles>
</xml>";

        $resultStr = sprintf($newsTpl, $object->FromUserName, $object->ToUserName, time(), count($arr_item));
        return $resultStr;
    }
}
?>