
<?php
/**
 * 微信支付服务器端下单
 * 微信APP支付文档地址:  https://pay.weixin.qq.com/wiki/doc/api/app.php?chapter=8_6
 * 使用示例
 *  构造方法参数
 *      'appid'     =>  //填写微信分配的公众账号ID
 *      'mch_id'    =>  //填写微信支付分配的商户号
 *      'notify_url'=>  //填写微信支付结果回调地址
 *      'key'       =>  //填写微信商户支付密钥
 *  );
 *  统一下单方法
 *  $WechatAppPay = new wechatAppPay($options);
 *  $params['body'] = '商品描述';                   //商品描述
 *  $params['out_trade_no'] = '1217752501201407';   //自定义的订单号，不能重复
 *  $params['total_fee'] = '100';                   //订单金额 只能为整数 单位为分
 *  $params['trade_type'] = 'APP';                  //交易类型 JSAPI | NATIVE |APP | WAP
 *  $wechatAppPay->unifiedOrder( $params );
 */
class weixin_public
{

    private $appid;
    private $seceret;
    private $uri;

    public function __construct($appid, $seceret, $uri)
    {
        $this->appid = $appid;
        $this->seceret = $seceret;
        $this->uri = $uri;
    }

    //获取code
    public function redirectWithCode()
    {
        $url = "https://open.weixin.qq.com/connect/oauth2/authorize?appid=".$this->appid
            ."&redirect_uri=".$this->uri
            ."&response_type=code&scope=snsapi_userinfo&state=STATE#wechat_redirect";

        header('Location: '.$url);
        exit;
    }


    public function getAccessToken()
    {
        $rs = Baseconfig::getInfoByKey(TOKEN_BASE_KEY);

        if (empty($rs) || (time() - $rs["lastupdate"]) > TOKEN_LIMIT_TIME) {
            $accessToken = self::refreshToken();
        } else {
            $accessToken = $rs["value"];
        }
        return $accessToken;
    }


    public function refreshToken()
    {
        $token_access_url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=" . $this->appid . "&secret=" . $this->seceret;
        $res = file_get_contents($token_access_url); //
        $result = json_decode($res, true); //接受一个 JSON 格式的字符串并且把它转换为 PHP 变量s
        $access_token = $result['access_token'];

        $rs = Baseconfig::getInfoByKey(TOKEN_BASE_KEY);
        if ($rs) {
            $res = Baseconfig::updateByKey(TOKEN_BASE_KEY, array("value" => $access_token, "lastupdate" => time()));
        } else {
            $attrs = array(
                "key"=>TOKEN_BASE_KEY,
                "value"=>$access_token,
                "name"=>"token"
            );
            $res = Baseconfig::add($attrs);
        }
        if ($res) {
            return $access_token;
        }
    }


}