<?php

class JSSDK
{
	private $appId;
	private $appSecret;

	public function __construct($appId, $appSecret)
	{
		$this->appId = $appId;
		$this->appSecret = $appSecret;
	}

	public function getSignPackage()
	{
		$jsapiTicket = $this->getJsApiTicket();
		$protocol = !empty($_SERVER[HTTPS]) && $_SERVER[HTTPS] !== off || $_SERVER[SERVER_PORT] == 443 ? 'https://' : 'http://';
		$url = $protocol . $_SERVER[HTTP_HOST] . $_SERVER[REQUEST_URI];
		$timestamp = time();
		$nonceStr = $this->createNonceStr();
		$string = 'jsapi_ticket=' . $jsapiTicket . '&noncestr=' . $nonceStr . '&timestamp=' . $timestamp . '&url=' . $url;
		$signature = sha1($string);
		$signPackage = array('appId' => $this->appId, 'nonceStr' => $nonceStr, 'timestamp' => $timestamp, 'url' => $url, 'signature' => $signature, 'rawString' => $string);
		return $signPackage;
	}

	private function createNonceStr($length = 16)
	{
		$chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
		$str = '';

		for ($i = 0; $i < $length; $i++) {
			$str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
		}

		return $str;
	}

	private function getJsApiTicket()
	{
		$data = json_decode($this->get_php_file(MYMPS_DATA . '/jsapi/jsapi_ticket.php'));

		if ($data->expire_time < time()) {
			$accessToken = $this->getAccessToken();
			$url = 'https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=' . $accessToken;
			$res = json_decode($this->httpGet($url));
			$ticket = $res->ticket;

			if ($ticket) {
				$data->expire_time = time() + 7000;
				$data->jsapi_ticket = $ticket;
				$this->set_php_file(MYMPS_DATA . '/jsapi/jsapi_ticket.php', json_encode($data));
			}
		}
		else {
			$ticket = $data->jsapi_ticket;
		}

		return $ticket;
	}

	private function getAccessToken()
	{
		$data = json_decode($this->get_php_file(MYMPS_DATA . '/jsapi/jsapi_access_token.php'));

		if ($data->expire_time < time()) {
			$url = 'https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=' . $this->appId . '&secret=' . $this->appSecret;
			$res = json_decode($this->httpGet($url));
			$access_token = $res->access_token;

			if ($access_token) {
				$data->expire_time = time() + 7000;
				$data->access_token = $access_token;
				$this->set_php_file(MYMPS_DATA . '/jsapi/jsapi_access_token.php', json_encode($data));
			}
		}
		else {
			$access_token = $data->access_token;
		}

		return $access_token;
	}

	private function httpGet($url)
	{
		$curl = curl_init();
		curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
		curl_setopt($curl, CURLOPT_TIMEOUT, 500);
		curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
		curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
		curl_setopt($curl, CURLOPT_URL, $url);
		$res = curl_exec($curl);
		curl_close($curl);
		return $res;
	}

	private function get_php_file($filename)
	{
		return trim(substr(file_get_contents($filename), 15));
	}

	private function set_php_file($filename, $content)
	{
		$fp = fopen($filename, 'w');
		fwrite($fp, '<?php exit();?>' . $content);
		fclose($fp);
	}
}


?>