<?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) 2013 (original work) Open Assessment Technologies SA (under the project TAO-PRODUCT);
 *
 *
 */

namespace oat\taoQtiItem\model\qti;

use oat\taoQtiItem\model\qti\IdentifierCollection;
use oat\taoQtiItem\model\qti\IdentifiedElement;
use oat\taoQtiItem\model\qti\exception\QtiModelException;

/**
 * The QTI_Item object represent the assessmentItem.
 * It's the main QTI object, it contains all the other objects and is the main
 * point
 * to render a complete item.
 *
 * @access public
 * @author Sam, <sam@taotesting.com>
 * @package taoQTI
 * @see http://www.imsglobal.org/question/qti_v2p0/imsqti_infov2p0.html#section10042

 */
class IdentifierCollection
{
    /**
     * The multi dimension array containing identified elements
     * array(identifier => serial => oat\taoQtiItem\model\qti\IdentifiedElement)
     *
     *
     */
    protected $elements = [];
    
    /**
     * Short description of method __construct
     *
     * @access public
     * @author Sam, <sam@taotesting.com>
     * @param  string identifier
     * @param  array options
     * @return mixed
     */
    public function __construct($identifiedElements = [])
    {
        $this->elements = [];
        if (is_array($identifiedElements)) {
            $this->addMultiple($identifiedElements);
        }
    }
    
    public function add(IdentifiedElement $element)
    {
        $identifier = $element->getIdentifier(false);
        if (!empty($identifier)) {
            if (!isset($this->elements[$identifier])) {
                $this->elements[$identifier] = [];
            }
            $this->elements[$identifier][$element->getSerial()] = $element;
        }
    }
    
    public function exists($identifier)
    {
        
        $returnValue = false;
        
        if (is_string($identifier)) {
            $returnValue = isset($this->elements[$identifier]);
        } else {
            throw new InvalidArgumentException('the identifier must be a string');
        }
        
        return $returnValue;
    }
    
    public function get($identifier = '')
    {
        
        $returnValue = [];
        
        if (empty($identifier)) {
            $returnValue = $this->elements;
        } elseif ($this->exists($identifier)) {
            $returnValue = $this->elements[$identifier];
        }
        
        return $returnValue;
    }
    
    public function getUnique($identifier, $elementClass = '')
    {
        
        $returnValue = null;
        
        if ($this->exists($identifier)) {
            if (empty($elementClass)) {
                if (count($this->elements[$identifier]) > 1) {
                    throw new QtiModelException('More than one identifier found, please try specifying the class of the element');
                } elseif (!empty($this->elements[$identifier])) {
                    $returnValue = reset($this->elements[$identifier]);
                }
            } else {
                $found = [];
                foreach ($this->elements[$identifier] as $elt) {
                    if ($elt instanceof $elementClass) {
                        $found[] = $elt;
                    }
                }
                if (count($found) > 1) {
                    throw new QtiModelException('More than one identifier found with the class: ' . $elementClass);
                } elseif (count($found) == 1) {
                    $returnValue = reset($found);
                }
            }
        }
        
        return $returnValue;
    }
    
    public function addMultiple($identifiedElements)
    {
        
        if (!is_array($identifiedElements)) {
            throw new InvalidArgumentException('the argument "identifiedElements" must be an array');
        }
        
        foreach ($identifiedElements as $identifiedElement) {
            if ($identifiedElement instanceof IdentifiedElement) {
                $this->add($identifiedElement);
            } elseif (is_array($identifiedElement)) {
                $this->addMultiple($identifiedElement);
            } else {
                throw new InvalidArgumentException('must be either an identifier or an array');
            }
        }
    }
    
    public function merge(IdentifierCollection $identifierCollection)
    {
        
        foreach ($identifierCollection->get() as $elements) {
            $this->addMultiple($elements);
        }
    }
}