<?
class MagEncoder
{
	public $json_encode = "";
	public $rec_encode = array();
	public $rec_ret = array();
	private $secret = "";
	private $deli = "|*|";

	public function __construct( $secret )
	{
		$this->secret = $secret;
	}

	public function GetMagEncoder($filename)
	{
		if (file_exists($filename)) {
			$fp = fopen($filename, "r");
			$this->json_encode = fgets($fp);
			fclose($fp);
			if ($this->json_encode == "") return null;
			$this->rec_encode = json_decode($this->json_encode, TRUE);
			$ret = explode($this->deli, $this->decrypt($this->rec_encode['sys_info']));
			$this->rec_ret['ip'] = $ret[0];
			$this->rec_ret['time'] = $ret[1];
			$this->rec_ret['msg'] = $ret[2];

			return ($this->rec_ret);
		}
		return null;
	}

	public function PutMagEncoder($filename, $ip, $time, $msg)
	{
		$this->rec_encode['sys_info'] = $this->encrypt($ip.$this->deli.$time.$this->deli.$msg);
		$this->json_encode = json_encode($this->rec_encode);

		$fp = fopen($filename, "w");
		fwrite($fp, $this->json_encode);	
		fclose($fp);
	}

	public function decrypt($hex_buf)
	    {
		$key = $this->secret;
		$len = strlen($hex_buf);
		for ($i=0; $i<$len; $i+=2)
		    $buf .= chr(hexdec(substr($hex_buf, $i, 2)));
		
		$key1 = pack("H*", md5($key));
		while($buf)
		{
		   $m = substr($buf, 0, 16);
		   $buf = substr($buf, 16);
		   
		   $c = "";
		   for($i=0;$i<16;$i++)
		   {
		       $c .= $m{$i}^$key1{$i};
		   }
		   
		   $ret_buf .= $m = $c;
		   $key1 = pack("H*",md5($key.$key1.$m));
		}
		
		return($ret_buf);
	    }
	    
	    function encrypt($buf)
	    {
		$key = $this->secret;
		$key1 = pack("H*",md5($key));
		while($buf)
		{
		    $m = substr($buf, 0, 16);
		    $buf = substr($buf, 16);
		    
		    $c = "";
		    for($i=0;$i<16;$i++)
		    {
			$c .= $m{$i}^$key1{$i};
		    }
		    $ret_buf .= $c;
		    $key1 = pack("H*",md5($key.$key1.$m));
		}
		
		$len = strlen($ret_buf);
		for($i=0; $i<$len; $i++)
		    $hex_data .= sprintf("%02x", ord(substr($ret_buf, $i, 1)));
		return($hex_data);
	    }


	public function base64encode($string) {  
		$data = str_replace(array('+','/','='),array('-','_',''),base64_encode($string));  
	    	return $data;  
	}  

	public function base64decode($string) {  
	    	$data = str_replace(array('-','_'),array('+','/'),$string);  
	    	$mod4 = strlen($data) % 4;  
	    	if ($mod4) {  
			$data .= substr('====', $mod4);  
	    	}  
	    	return base64_decode($data);  
	}  
}

//$test = new MagEncoder("test");
//$data = "허윤영 test is test1234";
//$enc_data = $test->encrypt($data);
//echo "$data -> ".$enc_data."\n";
//$de_data = $test->decrypt($enc_data);
//echo "$enc_data -> ".$de_data."\n";

// 생성시..
//$test->PutMagEncoder("test.txt", "10", "2017-12-31 23:59:59", "데모용입니다.");
// 테스트 시.. 
//$ret = $test->GetMagEncoder("test.txt");
//print_r($ret);
?>