<?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) 2020 (original work) Open Assessment Technologies SA;
 */

declare(strict_types=1);

namespace oat\taoMediaManager\model\sharedStimulus\parser;

use oat\tao\helpers\Base64;
use oat\oatbox\service\ConfigurableService;
use oat\tao\model\media\TaoMediaException;
use oat\tao\model\media\TaoMediaResolver;
use oat\taoMediaManager\model\MediaSource;
use qtism\data\storage\xml\XmlDocument;
use qtism\data\storage\xml\XmlStorageException;

class SharedStimulusMediaParser extends ConfigurableService
{
    /** @var TaoMediaResolver */
    private $mediaResolver;

    public function extractMedia(string $xml, callable $processImageIdentifier): array
    {
        try {
            $xmlDocument = new XmlDocument();
            $xmlDocument->loadFromString($xml, false);
        } catch (XmlStorageException $e) {
            throw new TaoMediaException('Shared stimulus XML cannot be processed.', 0, $e);
        }

        return array_merge(
            $this->processImages($xmlDocument, $processImageIdentifier),
            $this->processVideos($xmlDocument, $processImageIdentifier)
        );
    }

    public function withMediaResolver(TaoMediaResolver $resolver)
    {
        $this->mediaResolver = $resolver;

        return $this;
    }

    private function processImages(XmlDocument $xmlDocument, callable $processImageIdentifier): array
    {
        $mediaImages = [];
        $images = $xmlDocument->getDocumentComponent()->getComponentsByClassName('img');

        foreach ($images as $image) {
            $this->processMediaSource($image->getSrc(), $processImageIdentifier, $mediaImages);
        }

        return $mediaImages;
    }

    private function processVideos(XmlDocument $xmlDocument, callable $processImageIdentifier): array
    {
        $mediaVideos = [];
        $videos = $xmlDocument->getDocumentComponent()->getComponentsByClassName('object');

        foreach ($videos as $video) {
            $this->processMediaSource($video->getData(), $processImageIdentifier, $mediaVideos);
        }

        return $mediaVideos;
    }

    private function processMediaSource(string $uri, callable $processor, array &$matches): void
    {
        if (!Base64::isEncoded($uri)) {

            if (isset(parse_url($uri)['scheme'])) {
                $asset = $this->getMediaResolver()->resolve($uri);

                if ($asset->getMediaSource() instanceof MediaSource) {
                    $matches[] = $processor($asset);
                }
            }
        }
    }

    private function getMediaResolver(): TaoMediaResolver
    {
        if (!$this->mediaResolver) {
            $this->mediaResolver = new TaoMediaResolver();
        }

        return $this->mediaResolver;
    }
}