<?php

/*

 * This file is part of the Assetic package, an OpenSky project.

 *

 * (c) 2010-2011 OpenSky Project Inc

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

namespace Assetic\Factory\Loader;

use Assetic\Cache\ConfigCache;

use Assetic\Factory\Resource\IteratorResourceInterface;

use Assetic\Factory\Resource\ResourceInterface;

/**

 * Adds a caching layer to a loader.

 *

 * A cached formula loader is a composition of a formula loader and a cache.

 *

 * @author Kris Wallsmith <kris.wallsmith@gmail.com>

 */

class CachedFormulaLoader implements FormulaLoaderInterface

{

    private $loader;

    private $configCache;

    private $debug;

    /**

     * Constructor.

     *

     * When the loader is in debug mode it will ensure the cached formulae

     * are fresh before returning them.

     *

     * @param FormulaLoaderInterface $loader      A formula loader

     * @param ConfigCache            $configCache A config cache

     * @param Boolean                $debug       The debug mode

     */

    public function __construct(FormulaLoaderInterface $loader, ConfigCache $configCache, $debug = false)

    {

        $this->loader = $loader;

        $this->configCache = $configCache;

        $this->debug = $debug;

    }

    public function load(ResourceInterface $resources)

    {

        if (!$resources instanceof IteratorResourceInterface) {

            $resources = array($resources);

        }

        $formulae = array();

        foreach ($resources as $resource) {

            $id = (string) $resource;

            if (!$this->configCache->has($id) || ($this->debug && !$resource->isFresh($this->configCache->getTimestamp($id)))) {

                $formulae += $this->loader->load($resource);

                $this->configCache->set($id, $formulae);

            } else {

                $formulae += $this->configCache->get($id);

            }

        }

        return $formulae;

    }

}