<?php

class Planet_Cache
{

	/**
	 * @var int
	 */
	private static $now;

	/**
	 * @var bool
	 */
	private static $isClientCacheEnabled;

	/**
	 * @var bool
	 */
	private static $isServerCacheEnabled;

	/**
	 * Delete a cache entry
	 * @param string $uniqueId
	 */
	public static function delete($uniqueId = null)
	{
		if(null === $uniqueId)
		{
			if(!($uniqueId = self::createUniqueId())) return;
		}
		$cache = Zend_Registry::getInstance()->get('cache');
		if(null !== $cache){
			if($cache->test($uniqueId))
				$cache->remove($uniqueId);
		}
	}

	/**
	 * create a $uniqueId from the $request object
	 * [moduleName]_[controllerName]_[actionName]_param1_value1_param2_value2_
	 * eg. config
	 * 	cache.module.default.docs.view.cached
	 * @param Zend_Controller_Request_Abstract $request
	 */
	public static function createUniqueId($request = null)
	{
		if(null === $request) $request = Zend_Controller_Front::getInstance()->getRequest();
		$cache = Zend_Registry::getInstance()->get('cache');
		if(null !== $cache){
		   	$params = array();
	    	if(isset(Zend_Registry::getInstance()->configuration->cache->module->{$request->getModuleName()}->{$request->getControllerName()}->{$request->getActionName()}->params))
	    	{
	    		$params = Zend_Registry::getInstance()->configuration->cache->module->{$request->getModuleName()}->{$request->getControllerName()}->{$request->getActionName()}->params->toArray();
	    		sort($params);
	    	}
 		   	$uniqueId = $request->getModuleName().'_'.$request->getControllerName().'_'.$request->getActionName();
		   	if(!empty($params))
		   	{
		   		$uniqueId .= '_';
		   		foreach($params as $param)
		   			$uniqueId .= $param.'_'.strval($request->getParam($param)).'_';
		   	}
		   	return $uniqueId;
		}
		return false;
	}

	/**
	 * Determines if the client cache is enabled
	 * requires:
	 * 	server cache enabled
	 *  directive: cache.client.enabled = "true"
	 * @return bool
	 */
	public static function isClientCacheEnabled()
	{
    	if(null !== self::$isClientCacheEnabled) return self::$isClientCacheEnabled;
    	if(!self::isServerCacheEnabled()) return self::$isClientCacheEnabled = false;
    	return self::$isClientCacheEnabled = isset(Zend_Registry::getInstance()->configuration->cache->client->enabled) && Planet_Utils::Booleanize(Zend_Registry::getInstance()->configuration->cache->client->enabled);
	}

	/**
	 * Check if the cache directive exists in config and it's true
	 * Check if cache.module.[moduleName].[controllerName].[actionName].cached is TRUE
     *
	 * @param Zend_Controller_Request_Abstract $request
	 * @return bool
	 */
	public static function isServerCacheEnabled($request = null)
	{
		if(null !== self::$isServerCacheEnabled) return self::$isServerCacheEnabled;
		if(null === $request) $request = Zend_Controller_Front::getInstance()->getRequest();
		if(null === $request) throw new Planet_Exception('Request can\'t be NULL');
		/**
    	 * cache directive must be present in config
    	 */
		if(!isset(Zend_Registry::getInstance()->configuration->cache))
		{
    		return self::$isServerCacheEnabled = false;
		}

    	$c = Zend_Registry::getInstance()->configuration->cache; //alias
    	/**
    	 * cache.module.[moduleName].[controllerName].[actionName].cached = "true"
    	 * MUST be present ...
    	 */
    	if(!isset($c->module->{$request->getModuleName()}->{$request->getControllerName()}->{$request->getActionName()}->cached))
    	{
    		return self::$isServerCacheEnabled = false;
    	}
    	/**
    	 * ... and TRUE
    	 */
    	if(!Planet_Utils::Booleanize($c->module->{$request->getModuleName()}->{$request->getControllerName()}->{$request->getActionName()}->cached))
    	{
    		return self::$isServerCacheEnabled = false;
    	}

		return self::$isServerCacheEnabled = true;
	}

	/**
	 * get the cache lifetime
	 * @return string
	 */
	public static function getLifetime()
	{
		return isset(Zend_Registry::getInstance()->configuration->cache->lifetime) ? Zend_Registry::getInstance()->configuration->cache->lifetime : 0;
	}

	/**
	 * Get time()
	 */
	public static function getNow()
	{
		if(null !== self::$now) return self::$now;
		return self::$now = time();
	}

	/**
	 * Set the standard headers for caching
	 */
	public static function setClientHeaders()
	{
		$front = Zend_Controller_Front::getInstance();
		$front->getResponse()->setHeader("Date",gmdate('D M j G:i:s T Y', self::getNow()), true);
		$front->getResponse()->setHeader("Pragma","cache", true);
		$front->getResponse()->setHeader("Cache-Control","private", true);
		$front->getResponse()->setHeader('Expires', gmdate('D, d M Y H:i:s', self::getNow() + self::getLifetime()) . ' GMT', true);
    	$front->getResponse()->setHeader("Last-Modified", gmdate('D, d M Y H:i:s', self::getNow()).' GMT', true);
	}
}