<?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) 2008-2010 (original work) Deutsche Institut für Internationale Pädagogische Forschung (under the project TAO-TRANSFER);
 *               2009-2012 (update and modification) Public Research Centre Henri Tudor (under the project TAO-SUSTAIN & TAO-DEV);
 *
 */

/**
 * The ItemExporter class acts as the foundation for exporting item in XML packages. Developpers
 * who wants to create dedicated export behaviours can extend this class. To create a new export behaviour
 * developpers only need to implement the export abstract method. This is especially useful if a developper
 * needs to apply specific export procedures for items of a given Item Model. When you extend this class, you have
 * to respect a class naming convention. Actually, the class name must logicaly bound to the related Item Model label
 * in the knowledge base.
 *
 * QTI Items have their Item Model labeled QTI. Your ItemExporter should be then:
 * - named QTIItemExport where QTI is the Item model label, and ItemExport a suffix by convention.
 * - and the file containing its definition should be named class.QTIItemExport.php.
 *
 * When an item matching the QTI item model will be exported, the class QTIItemExporter will be dynamically loaded
 * and its QTIItemExporter::export() method invoked.
 *
 * @author CRP Henri Tudor - TAO Team - {@link http://www.tao.lu}
 * @license GPLv2  http://www.opensource.org/licenses/gpl-2.0.php
 * @package taoItems

 */

use Psr\Http\Message\StreamInterface;

abstract class taoItems_models_classes_ItemExporter
{


    private $item;
    private $zip;

    /**
     * Creates a new instance of ItemExporter for a particular item.
     *
     * @param core_kernel_classes_Resource $item The item to be exported.
     * @param ZipArchive $zip The ZIP archive were the files have to be exported.
     */
    public function __construct(core_kernel_classes_Resource $item, ZipArchive $zip)
    {
        $this->setItem($item);
        $this->setZip($zip);
    }
    
    /**
     * Obtains a reference on the TAO Item Service.
     *
     * @return taoItems_models_classes_ItemsService A TAO Item Service.
     */
    protected function getItemService()
    {
        return taoItems_models_classes_ItemsService::singleton();
    }
  
    /**
     * Obtains a reference on the currently exported instance of Item.
     *
     * @return core_kernel_classes_Resource The currently exported item.
     */
    protected function getItem()
    {
        return $this->item;
    }
    
    protected function setItem(core_kernel_classes_Resource $item)
    {
        $this->item = $item;
    }
   
    /**
     * Obtains a reference on the Zip Archive where the files related to the exported items will be stored.
     *
     * @return ZipArchive A created and open ZipArchive instance.
     */
    public function getZip()
    {
        return $this->zip;
    }
 
    public function setZip(ZipArchive $zip)
    {
        $this->zip = $zip;
    }
 
    /**
     * Obtains a reference on the Item Model related to the currently exported item instance.
     *
     * @return core_kernel_classes_Container
     */
    protected function getItemModel()
    {
        try {
            return $this->getItem()->getUniquePropertyValue(new core_kernel_classes_Property(taoItems_models_classes_ItemsService::PROPERTY_ITEM_MODEL));
        } catch (common_Exception $e) {
            return null;
        }
    }

    protected function getItemDirectory()
    {
        return $this->getItemService()->getItemDirectory($this->getItem());
    }
 
    /**
     * Add files or folders (and their content) to the Zip Archive that will contain all the files to the current export session.
     * For instance, if you want to copy the file 'taoItems/data/i123/item.xml' as 'myitem.xml' to your archive call addFile('path_to_item_location/item.xml', 'myitem.xml').
     * As a result, you will get a file entry in the final ZIP archive at '/i123/myitem.xml'.
     *
     * @param string | StreamInterface $src The path to the source file or folder to copy into the ZIP Archive.
     * @param string *dest The <u>relative</u> to the destination within the ZIP archive.
     * @return integer The amount of files that were transfered from TAO to the ZIP archive within the method call.
     */
    public function addFile($src, $dest)
    {
        $zip = $this->getZip();
        return tao_helpers_File::addFilesToZip($zip, $src, $dest);
    }
 
    abstract public function export();
}