<?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) 2014 (original work) Open Assessment Technologies SA (under the project TAO-PRODUCT);
 *
 */

namespace oat\taoQtiItem\model\qti\metadata\imsManifest;

use \DOMDocument;
use \DOMElement;
use oat\taoQtiItem\model\qti\metadata\imsManifest\classificationMetadata\ClassificationMetadataValue;
use oat\taoQtiItem\model\qti\metadata\imsManifest\classificationMetadata\ClassificationValue;
use oat\taoQtiItem\model\qti\metadata\MetadataInjectionException;
use oat\taoQtiItem\model\qti\metadata\MetadataInjector;
use oat\taoQtiItem\model\qti\metadata\MetadataValue;
use \InvalidArgumentException;

/**
 * A MetadataExtractor implementation.
 *
 * This implementation simply iterate through nodes and create an array of MetadataSimpleInstance object
 *
 * @author Antoine Robin <antoine.robin@vesperiagroup.com>
 * @author Jérôme Bogaerts <jerome@taotesting.com>
 */
class ImsManifestMetadataInjector implements MetadataInjector
{
    /**
     * An array of IMSManifesMapping object.
     *
     * @var ImsManifestMapping[]
     */
    private $mappings;

    /**
     * Create a new ImsManifestMetadataInjector object.
     *
     * @param ImsManifestMapping[] $mappings (optional) An array of ImsManifestMapping objects.
     */
    public function __construct(array $mappings = [])
    {
        $this->setMappings($mappings);
    }

    /**
     * Set the ImsManifestMapping objects of this injector.
     *
     * @param ImsManifestMapping[] $mappings An array of ImsManifestMapping objects.
     * @throws InvalidArgumentException If $mappings contains objects/values different from ImsManifestMapping.
     */
    protected function setMappings(array $mappings = [])
    {
        foreach ($mappings as $mapping) {
            if (!$mapping instanceof ImsManifestMapping) {
                $msg = "The mappings argument must be an array composed of ImsManifestMapping objects";
                throw new InvalidArgumentException($msg);
            }
        }

        $this->mappings = $mappings;
    }

    /**
     * Get the registered ImsManifestMapping objects. If no mapping
     * already registered, this method returns an empty array.
     *
     * @return ImsManifestMapping[] An array of ImsManifestMapping.
     */
    public function getMappings()
    {
        return $this->mappings;
    }

    /**
     * Add an XML mapping to this Manifest Extractor.
     *
     * If a mapping with an already registered XML namespace is given as
     * a $mapping, it is simply ignored.
     *
     * @param ImsManifestMapping $mapping An XML mapping.
     */
    public function addMapping(ImsManifestMapping $mapping)
    {
        $mappings = $this->getMappings();

        $ns = $mapping->getNamespace();

        if (isset($mappings[$ns]) === false) {
            $mappings[$ns] = $mapping;
        }

        $this->setMappings($mappings);
    }

    /**
     * Remove an already registered ImsManifestMapping.
     *
     * If $mapping cannot be found as a previously registered mapping, nothing happens.
     *
     * @param ImsManifestMapping $mapping An ImsManifestMapping object.
     */
    public function removeMapping(ImsManifestMapping $mapping)
    {
        $mappings = $this->getMappings();

        if (($key = array_search($mapping, $mappings, true)) !== false) {
            unset($mappings[$key]);
        }
    }

    /**
     * Remove a previously registered ImsManifestMapping by its namespace.
     *
     * If no previously registered ImsManifestMapping object can be found
     * for the given $namespace, nothing happens.
     *
     * @param string $namespace An XML namespace.
     */
    public function removeMappingByNamespace($namespace)
    {
        $mappings = $this->getMappings();

        if (isset($mappings[$namespace]) === true) {
            unset($mappings[$namespace]);
        }
    }

    /**
     * Clear all the previously registered ImsManifestMapping objects
     * from this injector.
     */
    public function clearMappings()
    {
        $this->setMappings();
    }

    /**
     * Inject some MetadataValue objects into the $target DOMElement object.
     *
     * The injection will take care of serializing the MetadataValue objects into the correct sections of the
     * the IMS Manifest File, by looking at previously registered IMSManifestMapping objects.
     *
     * @throws MetadataInjectionException If $target is not a DOMDocument object or something goes wrong during the injection process.
     */
    public function inject($target, array $values)
    {
        /** @var $target DOMDocument */
        if (! $target instanceof DOMDocument) {
            throw new MetadataInjectionException(__('The target must be an instance of DOMDocument'));
        }

        $map = [];

        // Inject the mapping in the root node
        foreach ($this->getMappings() as $mapping) {
            /** @var $root DOMElement */
            $root = $target->getElementsByTagName('manifest')->item(0);
            $root->setAttribute('xmlns:' . $mapping->getPrefix(), $mapping->getNamespace());
            $root->setAttribute(
                'xsi:schemaLocation',
                $root->getAttribute('xsi:schemaLocation') . ' ' . $mapping->getNamespace(
                ) . ' ' . $mapping->getSchemaLocation()
            );

            $map[$mapping->getNamespace()] = $mapping->getPrefix();
        }

        // Get all resource nodes
        $resources = $target->getElementsByTagName('resource');

        // Iterate through values to inject them in the DOMElement
        foreach ($values as $identifier => $metadataValues) {
            $metadataNode = null;

            // Search the node that has the given identifier
            /** @var $resource DOMElement */
            foreach ($resources as $resource) {
                if ($resource->getAttribute('identifier') === $identifier) {
                    // If metadata already exists we take it
                    if ($resource->getElementsByTagName('metadata')->length !== 0) {
                        $metadataNode = $resource->getElementsByTagName('metadata')->item(0);
                    } else {
                        $metadataNode = $target->createElement('metadata');
                    }

                    if ($resource->getElementsByTagName('file')->length !== 0) {
                        $fileNode = $resource->getElementsByTagName('file')->item(0);
                        $resource->insertBefore($metadataNode, $fileNode);
                    } else {
                        $resource->appendChild($metadataNode);
                    }
                    break;
                }
            }

            if (is_null($metadataNode) || empty($map)) {
                continue;
            }

            // Add the metadata values into the right path
            /** @var $metadata MetaDataValue */
            foreach ($metadataValues as $metadata) {
                $this->createMetadataElement($metadata, $metadataNode, $map, $target);
            }
        }
    }

    /**
     * Add an element based on MetadataValue object to DomDocument
     *
     * @param MetadataValue $metadata
     * @param DOMElement $metadataNode
     * @param $map
     * @param DOMDocument $imsManifest
     */
    protected function createMetadataElement(MetadataValue $metadata, DOMElement $metadataNode, $map, DOMDocument $imsManifest)
    {
        $path = $metadata->getPath();
        $path = array_reverse($path);

        $uniqNodes = [];
        if ($metadata instanceof ClassificationValue) {
            $uniqNodes = ['taxonPath', 'source'];
        }

        $oldChildNode = null;
        foreach ($path as $index => $element) {
            $name = substr($element, (strpos($element, '#') + 1));
            $base = substr($element, 0, (strpos($element, '#')));

            if (in_array($name, $uniqNodes) || is_null($oldChildNode) || $metadataNode->getElementsByTagName($map[$base] . ':' . $name)->length === 0) {
                $node = $imsManifest->createElement($map[$base] . ':' . $name);
            } else {
                $node = $metadataNode->getElementsByTagName($map[$base] . ':' . $name)->item(0);
            }

            if ($name == 'string' || $name == 'langstring') {
                $node->setAttribute('xml:lang', $metadata->getLanguage());
            }

            if (isset($oldChildNode)) {
                $node->appendChild($oldChildNode);
                if ($name == 'taxonPath' && $metadata instanceof ClassificationMetadataValue) {
                    foreach ($metadata->getEntries() as $entry) {
                        $this->createMetadataElement($entry, $node, $map, $imsManifest);
                    }
                }
            } else {
                $node->nodeValue = $metadata->getValue();
            }
            $oldChildNode = $node;
        }

        $metadataNode->appendChild($oldChildNode);
    }
}