<?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\Asset;

use Assetic\Cache\CacheInterface;

use Assetic\Filter\FilterInterface;

/**

 * Caches an asset to avoid the cost of loading and dumping.

 *

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

 */

class AssetCache implements AssetInterface

{

    private $asset;

    private $cache;

    public function __construct(AssetInterface $asset, CacheInterface $cache)

    {

        $this->asset = $asset;

        $this->cache = $cache;

    }

    public function ensureFilter(FilterInterface $filter)

    {

        $this->asset->ensureFilter($filter);

    }

    public function getFilters()

    {

        return $this->asset->getFilters();

    }

    public function clearFilters()

    {

        $this->asset->clearFilters();

    }

    public function load(FilterInterface $additionalFilter = null)

    {

        $cacheKey = self::getCacheKey($this->asset, $additionalFilter, 'load');

        if ($this->cache->has($cacheKey)) {

            $this->asset->setContent($this->cache->get($cacheKey));

            return;

        }

        $this->asset->load($additionalFilter);

        $this->cache->set($cacheKey, $this->asset->getContent());

    }

    public function dump(FilterInterface $additionalFilter = null)

    {

        $cacheKey = self::getCacheKey($this->asset, $additionalFilter, 'dump');

        if ($this->cache->has($cacheKey)) {

            return $this->cache->get($cacheKey);

        }

        $content = $this->asset->dump($additionalFilter);

        $this->cache->set($cacheKey, $content);

        return $content;

    }

    public function getContent()

    {

        return $this->asset->getContent();

    }

    public function setContent($content)

    {

        $this->asset->setContent($content);

    }

    public function getSourceRoot()

    {

        return $this->asset->getSourceRoot();

    }

    public function getSourcePath()

    {

        return $this->asset->getSourcePath();

    }

    public function getTargetPath()

    {

        return $this->asset->getTargetPath();

    }

    public function setTargetPath($targetPath)

    {

        $this->asset->setTargetPath($targetPath);

    }

    public function getLastModified()

    {

        return $this->asset->getLastModified();

    }

    /**

     * Returns a cache key for the current asset.

     *

     * The key is composed of everything but an asset's content:

     *

     *  * source root

     *  * source path

     *  * target url

     *  * last modified

     *  * filters

     *

     * @param AssetInterface  $asset            The asset

     * @param FilterInterface $additionalFilter Any additional filter being applied

     * @param string          $salt             Salt for the key

     *

     * @return string A key for identifying the current asset

     */

    static private function getCacheKey(AssetInterface $asset, FilterInterface $additionalFilter = null, $salt = '')

    {

        if ($additionalFilter) {

            $asset = clone $asset;

            $asset->ensureFilter($additionalFilter);

        }

        $cacheKey  = $asset->getSourceRoot();

        $cacheKey .= $asset->getSourcePath();

        $cacheKey .= $asset->getTargetPath();

        $cacheKey .= $asset->getLastModified();

        foreach ($asset->getFilters() as $filter) {

            $cacheKey .= serialize($filter);

        }

        return md5($cacheKey.$salt);

    }

}