<?php
namespace wx;

class Base
{
    /**
     * 获取普通token
     * @param $appid
     * @param $secret
     * @return mixed
     */
    public function getAccessToken($appid, $secret)
    {
        $url = 'https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid='.$appid.'&secret='.$secret.'';
        $res = $this->curl($url);
        $res = json_decode($res, true);
        if(isset($res['errcode'])){
            trace($res, 'error');
            return null;
        }
        return $res['access_token'];
    }

    /**
     * 请求接口
     * @param $url
     * @param null $data
     * @return mixed|null
     */
    protected function curl($url, $data=null)
    {
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $url);
        curl_setopt($curl, CURLOPT_HTTPHEADER, ['Content-type: application/json; encoding=utf-8']);
        if (!empty($data)) {
            curl_setopt($curl, CURLOPT_POST, 1);
            curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
        }

        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($curl, CURLOPT_HEADER, false);
    
        $data = curl_exec($curl);
        curl_close($curl);
        return $data;
    }

    /**
     * H5授权，code换accesstoken
     */
    public function getAccessTokenByCode($appid, $secret, $code)
    {
        $url = 'https://api.weixin.qq.com/sns/oauth2/access_token?appid=' . $appid . '&secret=' . $secret . '&code=' . $code . '&grant_type=authorization_code';
        $res = $this->curl($url);

        // 返回获取结果
        return json_decode($res, true);
    }

    /**
     * H5跳转获取code
     */
    public function redirectForCode($appid, $redirectUrl)
    {
        $url = 'https://open.weixin.qq.com/connect/oauth2/authorize?appid=' . $appid . '&redirect_uri=' . urlencode($redirectUrl) . '&response_type=code&scope=snsapi_userinfo&state=STATE#wechat_redirect';
        header('location:' . $url);
        exit;
    }
}