<?php
namespace Utility;


/**
 * Central cache functionality.
 * @author andre.fourie
 *
 */
class Cache
{

	/**
	 * @var \Memcache
	 */
	static protected $cache = null;
	/**
	 * @var boolean
	 */
	static protected $cacheKick = true;
	/**
	 * @var array
	 */
	static private $loadedFromCache = array();



	/**
	 * Store data in cache.
	 * @param string $key
	 * @param unknown $value
	 * @param integer $ttl
	 * @return boolean
	*/
	static public function store($key, $value, $ttl = 0)
	{
		if (is_null(self::$cache))
		{
			self::$cache = new \Memcache();
			self::$cache->pconnect('localhost', 11211);
		}
		return self::$cache->set($key, $value, 0, $ttl);
	}

	/**
	 * Fetch data from cache.
	 * @param string $key
	 * @param unknown $default
	 * @return unknown
	 */
	static public function fetch($key, $default = false)
	{
		if (is_null(self::$cache))
		{
			self::$cache = new \Memcache();
			self::$cache->pconnect('localhost', 11211);
		}
		$value = self::$cache->get($key);
		return false !== $value
			? $value
			: $default;

	}

	/**
	 * Delete cached item.
	 * @param string $key
	 */
	static public function delete($key)
	{
		if (is_null(self::$cache))
		{
			self::$cache = new \Memcache();
			self::$cache->pconnect('localhost', 11211);
		}
		self::$cache->delete($key);
	}

	/**
	 * Load a doctrine entity from cache. If not found in cache it will load from db and store in cache.
	 * @param string $entityName
	 * @param integer $id
	 * @param \Doctrine\ORM\EntityManager $em
	 * @param number $ttl
	 * @param number $depth
	 * @return unknown
	 */
	static public function fetchEntity($entityName, $id, \Doctrine\ORM\EntityManager $em, $ttl = 300, $depth = 1)
	{
		if (isset(self::$loadedFromCache[$entityName . $id]))
		{
			$record =  $em->getRepository($entityName)->find($id);
			return !is_null($record)
				? $record->toArray()
				: null;
		}
		$cachedEntity = self::fetch($entityName . '::' . $id);
		if (false !== $cachedEntity)
		{
			return $cachedEntity;
		}

		$entity = $em->getRepository($entityName)->find($id);
		if (!is_null($entity))
		{
			$entity = $entity->toArray();
			self::store($entityName . '::' . $id, $entity, $ttl);
			self::$loadedFromCache[$entityName . $id] = true;
		}
		return $entity;
	}

}