<?php
namespace LaneWeChat\Core;
class Wechat{
    private $debug;
    private $request;

    public function __construct($token, $debug = FALSE) {
        if ($this->isValid() && $this->validateSignature($token)) {
            return $_GET['echostr'];
        }
        $this->debug = $debug;
        $xml = (array) simplexml_load_string($GLOBALS['HTTP_RAW_POST_DATA'], 'SimpleXMLElement', LIBXML_NOCDATA);
        $this->request = array_change_key_case($xml, CASE_LOWER);
    }

    private function isValid() {
        return isset($_GET['echostr']);
    }

    private function validateSignature($token) {
        $signature = $_GET['signature'];
        $timestamp = $_GET['timestamp'];
        $nonce = $_GET['nonce'];
        $signatureArray = array($token, $timestamp, $nonce);
        sort($signatureArray, SORT_STRING);
        return sha1(implode($signatureArray)) == $signature;
    }

    protected function getRequest($param = FALSE) {
        if ($param === FALSE) {
            return $this->request;
        }
        $param = strtolower($param);
        if (isset($this->request[$param])) {
            return $this->request[$param];
        }
        return NULL;
    }

    public function run() {
        return WechatRequest::switchType($this->request);
    }

    public function checkSignature()
    {
        $signature = $_GET["signature"];
        $timestamp = $_GET["timestamp"];
        $nonce = $_GET["nonce"];

        $token = WECHAT_TOKEN;
        $tmpArr = array($token, $timestamp, $nonce);
        sort($tmpArr, SORT_STRING);
        $tmpStr = implode( $tmpArr );
        $tmpStr = sha1( $tmpStr );

        if( $tmpStr == $signature ){
            echo $_GET['echostr'];
            return true;
        }else{
            return false;
        }
    }
}