<?php

/**
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; under version 2
 * of the License (non-upgradable).
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * Copyright (c) 2017 (original work) Open Assessment Technologies SA
 *
 */

namespace oat\tao\model\upload;

use oat\generis\persistence\PersistenceManager;
use oat\oatbox\filesystem\File;
use Zend\ServiceManager\ServiceLocatorAwareInterface;
use Zend\ServiceManager\ServiceLocatorAwareTrait;
use Zend\ServiceManager\ServiceLocatorInterface;

class TempFlyStorageAssociation implements TmpLocalAwareStorageInterface, ServiceLocatorAwareInterface
{
    use ServiceLocatorAwareTrait;

    /**
     * @param ServiceLocatorInterface $serviceLocator
     */
    public function __construct(ServiceLocatorInterface $serviceLocator)
    {
        $this->setServiceLocator($serviceLocator);
    }

    /**
     * @param File $file
     * @throws \common_Exception
     */
    public function setUpload(File $file)
    {
        $hash = $this->getHashedKey($file);
        $this->set($hash, []);
    }

    /**
     * @param File $remote
     * @param string $local
     * @throws \common_Exception
     */
    public function addLocalCopies(File $remote, $local)
    {
        $hash = $this->getHashedKey($remote);
        $current = $this->getLocalCopies($remote);
        $current[] = $local;
        $this->set($hash, $current);
    }

    /**
     * @param $file
     * @return array
     */
    public function getLocalCopies(File $file)
    {
        $result = $this->get($this->getHashedKey($file));
        return is_array($result) ? $result : [];
    }


    /**
     * @param File $file
     * @return string
     */
    private function getHashedKey(File $file)
    {
        return md5($file->getPrefix());
    }

    /**
     * @param File $file
     */
    public function removeFiles(File $file)
    {
        $this->remove($this->getHashedKey($file));
    }

    /**
     * @return \common_persistence_KeyValuePersistence
     */
    private function getKvStorage()
    {
        /** @var PersistenceManager $pm */
        $pm = $this->getServiceLocator()->get(PersistenceManager::SERVICE_ID);
        return $pm->getPersistenceById('default_kv');
    }

    /**
     * @param $key
     * @param $val
     * @throws \common_Exception
     */
    private function set($key, $val)
    {
        $key = $this->getPrefix() . $key;
        $this->getKvStorage()->set($key, json_encode($val));
    }

    /**
     * @param $key
     */
    private function remove($key)
    {
        $key = $this->getPrefix() . $key;
        $this->getKvStorage()->del($key);
    }

    /**
     * @param $key
     * @return mixed|null
     */
    private function get($key)
    {
        $key = $this->getPrefix() . $key;
        if ($this->getKvStorage()->exists($key)) {
            return json_decode($this->getKvStorage()->get($key), true);
        }
        return null;
    }

    /**
     * @return string
     */
    private function getPrefix()
    {
        return static::class;
    }
}