<?php

namespace SilverStripe\VersionFeed\Filters;


use SilverStripe\Core\Config\Config;


/**
 * Caches results of a callback
 */
class CachedContentFilter extends ContentFilter {
	
	/**
	 * Enable caching
	 *
	 * @config
	 * @var boolean
	 */
	private static $cache_enabled = true;
	
	public function getContent($key, $callback) {
		$cache = $this->getCache();
		
		// Return cached value if available
		$cacheEnabled = Config::inst()->get(get_class(), 'cache_enabled');
		$result = (isset($_GET['flush']) || !$cacheEnabled)
			? null
			: $cache->load($key);
		if($result) return $result;
		
		// Fallback to generate result
		$result = parent::getContent($key, $callback);
		$cache->save($result, $key);
		return $result;
	}
}