<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\Cache\Adapter;

use Symfony\Component\Cache\Exception\InvalidArgumentException;

/**
 * @author Nicolas Grekas <p@tchwork.com>
 */
class FilesystemAdapter extends AbstractAdapter
{
    private $directory;

    public function __construct($directory, $defaultLifetime = null)
    {
        parent::__construct('', $defaultLifetime);

        if (!file_exists($dir = $directory.'/.')) {
            @mkdir($directory, 0777, true);
        }
        if (false === $dir = realpath($dir)) {
            throw new InvalidArgumentException(sprintf('Cache directory does not exist (%s)', $directory));
        }
        if (!is_writable($dir .= DIRECTORY_SEPARATOR)) {
            throw new InvalidArgumentException(sprintf('Cache directory is not writable (%s)', $directory));
        }
        // On Windows the whole path is limited to 258 chars
        if ('\\' === DIRECTORY_SEPARATOR && strlen($dir) > 190) {
            throw new InvalidArgumentException(sprintf('Cache directory too long (%s)', $directory));
        }

        $this->directory = $dir;
    }

    /**
     * {@inheritdoc}
     */
    protected function doFetch(array $ids)
    {
        $values = array();
        $now = time();

        foreach ($ids as $id) {
            $file = $this->getFile($id);
            if (!$h = @fopen($file, 'rb')) {
                continue;
            }
            flock($h, LOCK_SH);
            if ($now >= (int) $expiresAt = fgets($h)) {
                flock($h, LOCK_UN);
                fclose($h);
                if (isset($expiresAt[0])) {
                    @unlink($file);
                }
            } else {
                $value = stream_get_contents($h);
                flock($h, LOCK_UN);
                fclose($h);
                $values[$id] = unserialize($value);
            }
        }

        return $values;
    }

    /**
     * {@inheritdoc}
     */
    protected function doHave($id)
    {
        $file = $this->getFile($id);

        return file_exists($file) && (@filemtime($file) > time() || $this->doFetch(array($id)));
    }

    /**
     * {@inheritdoc}
     */
    protected function doClear($namespace)
    {
        $ok = true;

        foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($this->directory, \FilesystemIterator::SKIP_DOTS)) as $file) {
            $ok = ($file->isDir() || @unlink($file) || !file_exists($file)) && $ok;
        }

        return $ok;
    }

    /**
     * {@inheritdoc}
     */
    protected function doDelete(array $ids)
    {
        $ok = true;

        foreach ($ids as $id) {
            $file = $this->getFile($id);
            $ok = (!file_exists($file) || @unlink($file) || !file_exists($file)) && $ok;
        }

        return $ok;
    }

    /**
     * {@inheritdoc}
     */
    protected function doSave(array $values, $lifetime)
    {
        $ok = true;
        $expiresAt = $lifetime ? time() + $lifetime : PHP_INT_MAX;

        foreach ($values as $id => $value) {
            $file = $this->getFile($id);
            $dir = dirname($file);
            if (!file_exists($dir)) {
                @mkdir($dir, 0777, true);
            }
            $value = $expiresAt."\n".serialize($value);
            if (false !== @file_put_contents($file, $value, LOCK_EX)) {
                @touch($file, $expiresAt);
            } else {
                $ok = false;
            }
        }

        return $ok;
    }

    private function getFile($id)
    {
        $hash = hash('sha256', $id);

        return $this->directory.$hash[0].DIRECTORY_SEPARATOR.$hash[1].DIRECTORY_SEPARATOR.$hash;
    }
}