<?php
define('ENCODE_VARS', true);

class MY_Output extends CI_Output {
	var $cache_vars;
	var $cache_age;
	
	function MY_Output()
	{
		parent::CI_Output();

		$this->cache_vars = array();
		$this->cache_age = time();
	}
	
	function cache_by_vars($timeout, $cache_vars = array())
	{
		parent::cache($timeout);
		
		$this->set_cache_vars($cache_vars);
	}
	
	function set_cache_vars($cache_vars)
	{
		$this->cache_vars = array();
		
		if (is_array($cache_vars))
		{
			foreach ($cache_vars as $var => $value) {
				$this->add_cache_var($var, $value);
			}			
		}
		else {	
			$this->add_cache_var(NULL, $cache_vars)	;
			echo "hi.";
		}
	}
	
	function add_cache_var($var, $value) 
	{
		if ($var == NULL)
		{
			$this->cache_vars[] = $value;
			//printf("<pre>next = %s</pre>", $value)	;
		}
		else 
		{
			$this->cache_vars[$var] = $value;
			//printf("<pre>%s = %s</pre>", $var, $value)	;
		}
	}
	
	function cache_override() {
		return;
	}

	/**
	 * Write a Cache File
	 *
	 * @access	public
	 * @return	void
	 */	
	function _write_cache($output)
	{
		
		$filepath = $this->_cache_filename();
		$cache_path = dirname($filepath);
		
		if ( ! is_dir($cache_path) OR ! is_writable($cache_path))
		{
			return;
		}		

		if ( ! $fp = @fopen($filepath, 'wb'))
		{
			log_message('error', "Unable to write cache file: ".$filepath);
			return;
		}
		
		$expire = time() + ($this->cache_expiration * 60);
		
		flock($fp, LOCK_EX);
		fwrite($fp, $expire.'TS--->'.$output);
		flock($fp, LOCK_UN);
		fclose($fp);
		@chmod($filepath, 0777);
		
		log_message('debug', "Cache file written: ". $filepath);
	}
	
	/**
	 * Invalidate a Cache File
	 *
	 * @access	public
	 * @return	bool
	 */	
	function clear_cache()
	{
		$cleared = TRUE;
		if (file_exists($this->_cache_filename()))
		{
			$cleared = @unlink($this->_cache_filename());
		}
		
		return $cleared;
	}

	// --------------------------------------------------------------------
	
	/**
	 * Update/serve a cached file
	 *
	 * @access	public
	 * @return	void
	 */	
	function display_cache($cache_vars = array())
	{
		if (!empty($cache_vars))
		{
			$this->set_cache_vars = $cache_vars;
		}
		
		$filepath = $this->_cache_filename();
		$cache_path = dirname($filepath);

		/* CHAMPS:
		 * Removed some useless checks to see if $cache_path exists and is writable
		 * 
		 * also dropped the file_exists check, because @fopen() will handle that, and it's not a special error.
		 */
	
		if ( ! $fp = @fopen($filepath, 'rb'))
		{
			return FALSE;
		}
			
		flock($fp, LOCK_SH);
		
		$cache = '';
		if (filesize($filepath) > 0)
		{
			$cache = fread($fp, filesize($filepath));
		}
	
		flock($fp, LOCK_UN);
		fclose($fp);
					
		// Strip out the embedded timestamp		
		if ( ! preg_match("/(\d+TS--->)/", $cache, $match))
		{
			return FALSE;
		}
		
		// Has the file expired? If so we'll delete it.
		if (time() >= trim(str_replace('TS--->', '', $match['1'])))
		{ 		
			@unlink($filepath);
			log_message('debug', "Cache file has expired. File deleted");
			return FALSE;
		}

		// Display the cache
		// CHAMPS: I think this wasn't necessary with the old code because cache_expiration never got set.
		$this->cache_expiration = 0;
		
		$this->_display(str_replace($match['0'], '', $cache));
		log_message('debug', "Cache file is current. Sending it to browser.");		
		
		$this->cache_age = filemtime($filepath);

		return TRUE;	
	}
	
	
	function _cache_filename() {
		$CI =& get_instance();
		
		$cache_dir = $CI->config->item('cache_dir');
		if ($cache_dir == '')
		{
			$cache_dir = BASEPATH . 'cache/';
		}

		if (empty($this->cache_vars))
		{	
			$key =	$CI->config->item('base_url').
					$CI->config->item('index_page').
					$CI->uri->uri_string();		
		}
		else
		{
			$key = '';
			ksort($this->cache_vars);
			
			foreach ($this->cache_vars as $key => $value)
			{
				$key = $key . '=' . $value . '&';
			}	
		}

		if (ENCODE_VARS)
		{
			$key = md5($key);
		}
		
		return $cache_dir . $key;
	}
}
?>