<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * \core_h5p\framework class
 *
 * @package    core_h5p
 * @copyright  2019 Mihail Geshoski <mihail@moodle.com>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

namespace core_h5p;

defined('MOODLE_INTERNAL') || die();

/**
 * Moodle's implementation of the H5P framework interface.
 *
 * @package    core_h5p
 * @copyright  2019 Mihail Geshoski <mihail@moodle.com>
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class framework implements \H5PFrameworkInterface {

    /** @var string The path to the last uploaded h5p */
    private $lastuploadedfolder;

    /** @var string The path to the last uploaded h5p file */
    private $lastuploadedfile;

    /** @var stored_file The .h5p file */
    private $file;

    /**
     * Returns info for the current platform.
     * Implements getPlatformInfo.
     *
     * @return array An associative array containing:
     *               - name: The name of the platform, for instance "Moodle"
     *               - version: The version of the platform, for instance "3.8"
     *               - h5pVersion: The version of the H5P component
     */
    public function getPlatformInfo() {
        global $CFG;

        return array(
            'name' => 'Moodle',
            'version' => $CFG->version,
            'h5pVersion' => $CFG->version,
        );
    }

    /**
     * Fetches a file from a remote server using HTTP GET.
     * Implements fetchExternalData.
     *
     * @param string $url Where you want to get or send data
     * @param array $data Data to post to the URL
     * @param bool $blocking Set to 'FALSE' to instantly time out (fire and forget)
     * @param string $stream Path to where the file should be saved
     * @return string The content (response body). NULL if something went wrong
     */
    public function fetchExternalData($url, $data = null, $blocking = true, $stream = null) {

        if ($stream === null) {
            // Download file.
            set_time_limit(0);

            // Get the extension of the remote file.
            $parsedurl = parse_url($url);
            $ext = pathinfo($parsedurl['path'], PATHINFO_EXTENSION);

            // Generate local tmp file path.
            $fs = new \core_h5p\file_storage();
            $localfolder = $fs->getTmpPath();
            $stream = $localfolder;

            // Add the remote file's extension to the temp file.
            if ($ext) {
                $stream .= '.' . $ext;
            }

            $this->getUploadedH5pFolderPath($localfolder);
            $this->getUploadedH5pPath($stream);
        }

        $response = download_file_content($url, null, $data, true, 300, 20,
                false, $stream);

        if (empty($response->error) && ($response->status != '404')) {
            return $response->results;
        } else {
            $this->setErrorMessage($response->error, 'failed-fetching-external-data');
        }
    }

    /**
     * Set the tutorial URL for a library. All versions of the library is set.
     * Implements setLibraryTutorialUrl.
     *
     * @param string $libraryname
     * @param string $url
     */
    public function setLibraryTutorialUrl($libraryname, $url) {
        // Tutorial url is currently not being used or stored in libraries.
    }

    /**
     * Set an error message.
     * Implements setErrorMessage.
     *
     * @param string $message The error message
     * @param string $code An optional code
     */
    public function setErrorMessage($message, $code = null) {
        if ($message !== null) {
            $this->set_message('error', $message, $code);
        }
    }

    /**
     * Set an info message.
     * Implements setInfoMessage.
     *
     * @param string $message The info message
     */
    public function setInfoMessage($message) {
        if ($message !== null) {
            $this->set_message('info', $message);
        }
    }

    /**
     * Return messages.
     * Implements getMessages.
     *
     * @param string $type The message type, e.g. 'info' or 'error'
     * @return string[] Array of messages
     */
    public function getMessages($type) {
        global $SESSION;

        // Return and reset messages.
        $messages = array();
        if (isset($SESSION->core_h5p_messages[$type])) {
            $messages = $SESSION->core_h5p_messages[$type];
            unset($SESSION->core_h5p_messages[$type]);
            if (empty($SESSION->core_h5p_messages)) {
                unset($SESSION->core_h5p_messages);
            }
        }

        return $messages;
    }

    /**
     * Translation function.
     * The purpose of this function is to map the strings used in the core h5p methods
     * and replace them with the translated ones. If a translation for a particular string
     * is not available, the default message (key) will be returned.
     * Implements t.
     *
     * @param string $message The english string to be translated
     * @param array $replacements An associative array of replacements to make after translation
     * @return string Translated string or the english string if a translation is not available
     */
    public function t($message, $replacements = array()) {

        // Create mapping.
        $translationsmap = [
            'The file you uploaded is not a valid HTML5 Package (It does not have the .h5p file extension)' => 'noextension',
            'The file you uploaded is not a valid HTML5 Package (We are unable to unzip it)' => 'nounzip',
            'The main h5p.json file is not valid' => 'nojson',
            'Library directory name must match machineName or machineName-majorVersion.minorVersion (from library.json).' .
                ' (Directory: %directoryName , machineName: %machineName, majorVersion: %majorVersion, minorVersion:' .
                ' %minorVersion)'
                => 'librarydirectoryerror',
            'A valid content folder is missing' => 'missingcontentfolder',
            'A valid main h5p.json file is missing' => 'invalidmainjson',
            'Missing required library @library' => 'missinglibrary',
            "Note that the libraries may exist in the file you uploaded, but you're not allowed to upload new libraries." .
                ' Contact the site administrator about this.' => 'missinguploadpermissions',
            'Invalid library name: %name' => 'invalidlibraryname',
            'Could not find library.json file with valid json format for library %name' => 'missinglibraryjson',
            'Invalid semantics.json file has been included in the library %name' => 'invalidsemanticsjson',
            'Invalid language file %file in library %library' => 'invalidlanguagefile',
            'Invalid language file %languageFile has been included in the library %name' => 'invalidlanguagefile2',
            'The file "%file" is missing from library: "%name"' => 'missinglibraryfile',
            'The system was unable to install the <em>%component</em> component from the package, it requires a newer' .
                ' version of the H5P plugin. This site is currently running version %current, whereas the required version' .
                ' is %required or higher. You should consider upgrading and then try again.' => 'missingcoreversion',
            "Invalid data provided for %property in %library. Boolean expected." => 'invalidlibrarydataboolean',
            "Invalid data provided for %property in %library" => 'invalidlibrarydata',
            "Can't read the property %property in %library" => 'invalidlibraryproperty',
            'The required property %property is missing from %library' => 'missinglibraryproperty',
            'Illegal option %option in %library' => 'invalidlibraryoption',
            'Added %new new H5P library and updated %old old one.' => 'addedandupdatedss',
            'Added %new new H5P library and updated %old old ones.' => 'addedandupdatedsp',
            'Added %new new H5P libraries and updated %old old one.' => 'addedandupdatedps',
            'Added %new new H5P libraries and updated %old old ones.' => 'addedandupdatedpp',
            'Added %new new H5P library.' => 'addednewlibrary',
            'Added %new new H5P libraries.' => 'addednewlibraries',
            'Updated %old H5P library.' => 'updatedlibrary',
            'Updated %old H5P libraries.' => 'updatedlibraries',
            'Missing dependency @dep required by @lib.' => 'missingdependency',
            'Provided string is not valid according to regexp in semantics. (value: "%value", regexp: "%regexp")'
                => 'invalidstring',
            'File "%filename" not allowed. Only files with the following extensions are allowed: %files-allowed.'
                => 'invalidfile',
            'Invalid selected option in multi-select.' => 'invalidmultiselectoption',
            'Invalid selected option in select.' => 'invalidselectoption',
            'H5P internal error: unknown content type "@type" in semantics. Removing content!' => 'invalidsemanticstype',
            'Copyright information' => 'copyrightinfo',
            'Title' => 'title',
            'Author' => 'author',
            'Year(s)' => 'years',
            'Year' => 'year',
            'Source' => 'source',
            'License' => 'license',
            'Undisclosed' => 'undisclosed',
            'General Public License v3' => 'gpl',
            'Public Domain' => 'pd',
            'Public Domain Dedication and Licence' => 'pddl',
            'Public Domain Mark' => 'pdm',
            'Public Domain Mark (PDM)' => 'pdm',
            'Copyright' => 'copyrightstring',
            'The mbstring PHP extension is not loaded. H5P need this to function properly' => 'missingmbstring',
            'The version of the H5P library %machineName used in this content is not valid. Content contains %contentLibrary, ' .
                'but it should be %semanticsLibrary.' => 'wrongversion',
            'The H5P library %library used in the content is not valid' => 'invalidlibrarynamed',
            'Fullscreen' => 'fullscreen',
            'Disable fullscreen' => 'disablefullscreen',
            'Download' => 'download',
            'Rights of use' => 'copyright',
            'Embed' => 'embed',
            'Size' => 'size',
            'Show advanced' => 'showadvanced',
            'Hide advanced' => 'hideadvanced',
            'Include this script on your website if you want dynamic sizing of the embedded content:' => 'resizescript',
            'Close' => 'close',
            'Thumbnail' => 'thumbnail',
            'No copyright information available for this content.' => 'nocopyright',
            'Download this content as a H5P file.' => 'downloadtitle',
            'View copyright information for this content.' => 'copyrighttitle',
            'View the embed code for this content.' => 'embedtitle',
            'Visit H5P.org to check out more cool content.' => 'h5ptitle',
            'This content has changed since you last used it.' => 'contentchanged',
            "You'll be starting over." => 'startingover',
            'by' => 'by',
            'Show more' => 'showmore',
            'Show less' => 'showless',
            'Sublevel' => 'sublevel',
            'Confirm action' => 'confirmdialogheader',
            'Please confirm that you wish to proceed. This action is not reversible.' => 'confirmdialogbody',
            'Cancel' => 'cancellabel',
            'Confirm' => 'confirmlabel',
            '4.0 International' => 'licenseCC40',
            '3.0 Unported' => 'licenseCC30',
            '2.5 Generic' => 'licenseCC25',
            '2.0 Generic' => 'licenseCC20',
            '1.0 Generic' => 'licenseCC10',
            'General Public License' => 'licenseGPL',
            'Version 3' => 'licenseV3',
            'Version 2' => 'licenseV2',
            'Version 1' => 'licenseV1',
            'CC0 1.0 Universal (CC0 1.0) Public Domain Dedication' => 'licenseCC010',
            'CC0 1.0 Universal' => 'licenseCC010U',
            'License Version' => 'licenseversion',
            'Creative Commons' => 'creativecommons',
            'Attribution' => 'ccattribution',
            'Attribution (CC BY)' => 'ccattribution',
            'Attribution-ShareAlike' => 'ccattributionsa',
            'Attribution-ShareAlike (CC BY-SA)' => 'ccattributionsa',
            'Attribution-NoDerivs' => 'ccattributionnd',
            'Attribution-NoDerivs (CC BY-ND)' => 'ccattributionnd',
            'Attribution-NonCommercial' => 'ccattributionnc',
            'Attribution-NonCommercial (CC BY-NC)' => 'ccattributionnc',
            'Attribution-NonCommercial-ShareAlike' => 'ccattributionncsa',
            'Attribution-NonCommercial-ShareAlike (CC BY-NC-SA)' => 'ccattributionncsa',
            'Attribution-NonCommercial-NoDerivs' => 'ccattributionncnd',
            'Attribution-NonCommercial-NoDerivs (CC BY-NC-ND)' => 'ccattributionncnd',
            'Public Domain Dedication (CC0)' => 'ccpdd',
            'Years (from)' => 'yearsfrom',
            'Years (to)' => 'yearsto',
            "Author's name" => 'authorname',
            "Author's role" => 'authorrole',
            'Editor' => 'editor',
            'Licensee' => 'licensee',
            'Originator' => 'originator',
            'Any additional information about the license' => 'additionallicenseinfo',
            'License Extras' => 'licenseextras',
            'Changelog' => 'changelog',
            'Content Type' => 'contenttype',
            'Date' => 'date',
            'Changed by' => 'changedby',
            'Description of change' => 'changedescription',
            'Photo cropped, text changed, etc.' => 'changeplaceholder',
            'Author comments' => 'authorcomments',
            'Comments for the editor of the content (This text will not be published as a part of copyright info)'
                => 'authorcommentsdescription',
            'Reuse' => 'reuse',
            'Reuse Content' => 'reuseContent',
            'Reuse this content.' => 'reuseDescription',
            'Content is copied to the clipboard' => 'contentCopied',
            'Connection lost. Results will be stored and sent when you regain connection.' => 'connectionLost',
            'Connection reestablished.' => 'connectionReestablished',
            'Attempting to submit stored results.' => 'resubmitScores',
            'Your connection to the server was lost' => 'offlineDialogHeader',
            'We were unable to send information about your completion of this task. Please check your internet connection.'
                => 'offlineDialogBody',
            'Retrying in :num....' => 'offlineDialogRetryMessage',
            'Retry now' => 'offlineDialogRetryButtonLabel',
            'Successfully submitted results.' => 'offlineSuccessfulSubmit',
            'One of the files inside the package exceeds the maximum file size allowed. (%file %used > %max)'
                => 'fileExceedsMaxSize',
            'The total size of the unpacked files exceeds the maximum size allowed. (%used > %max)'
                => 'unpackedFilesExceedsMaxSize',
            'Unable to read file from the package: %fileName' => 'couldNotReadFileFromZip',
            'Unable to parse JSON from the package: %fileName' => 'couldNotParseJSONFromZip',
            'A problem with the server write access was detected. Please make sure that your server can write to your data folder.' => 'nowriteaccess',
            'H5P hub communication has been disabled because one or more H5P requirements failed.' => 'hubcommunicationdisabled',
            'Site could not be registered with the hub. Please contact your site administrator.' => 'sitecouldnotberegistered',
            'The H5P Hub has been disabled until this problem can be resolved. You may still upload libraries through the "H5P Libraries" page.' => 'hubisdisableduploadlibraries',
            'When you have revised your server setup you may re-enable H5P hub communication in H5P Settings.' => 'reviseserversetupandretry',
            'You have been provided a unique key that identifies you with the Hub when receiving new updates. The key is available for viewing in the "H5P Settings" page.' => 'sitekeyregistered',
            'Your PHP max post size is quite small. With your current setup, you may not upload files larger than {$a->%number} MB. This might be a problem when trying to upload H5Ps, images and videos. Please consider to increase it to more than 5MB' => 'maxpostsizetoosmall',
            'Your PHP max upload size is bigger than your max post size. This is known to cause issues in some installations.' => 'uploadsizelargerthanpostsize',
            'Your PHP max upload size is quite small. With your current setup, you may not upload files larger than {$a->%number} MB. This might be a problem when trying to upload H5Ps, images and videos. Please consider to increase it to more than 5MB.' => 'maxuploadsizetoosmall',
            'Your PHP version does not support ZipArchive.' => 'noziparchive',
            'Your PHP version is outdated. H5P requires version 5.2 to function properly. Version 5.6 or later is recommended.' => 'oldphpversion',
            'Your server does not have SSL enabled. SSL should be enabled to ensure a secure connection with the H5P hub.' => 'sslnotenabled',
            'Your site was successfully registered with the H5P Hub.' => 'successfullyregisteredwithhub'
        ];

        if (isset($translationsmap[$message])) {
            return get_string($translationsmap[$message], 'core_h5p', $replacements);
        }

        debugging("String translation cannot be found. Please add a string definition for '" .
            $message . "' in the core_h5p component.", DEBUG_DEVELOPER);

        return $message;
    }

    /**
     * Get URL to file in the specifimake_pluginfile_urlc library.
     * Implements getLibraryFileUrl.
     *
     * @param string $libraryfoldername The name or path of the library's folder
     * @param string $filename The file name
     * @return string URL to file
     */
    public function getLibraryFileUrl($libraryfoldername, $filename) {
        global $DB;

        // Remove unnecessary slashes (first and last, if present) from the path to the folder
        // of the library file.
        $libraryfilepath = trim($libraryfoldername, '/');

        // Get the folder name of the library from the path.
        // The first element should represent the folder name of the library.
        $libfoldername = explode('/', $libraryfilepath)[0];

        $factory = new \core_h5p\factory();
        $core = $factory->get_core();

        // The provided folder name of the library must have a valid format (can be parsed).
        // The folder name is parsed with a purpose of getting the library related information
        // such as 'machineName', 'majorVersion' and 'minorVersion'.
        // This information is later used to retrieve the library ID.
        if (!$libdata = $core->libraryFromString($libfoldername, true)) {
            debugging('The provided string value "' . $libfoldername .
                '" is not a valid name for a library folder.', DEBUG_DEVELOPER);

            return;
        }

        $params = array(
            'machinename' => $libdata['machineName'],
            'majorversion' => $libdata['majorVersion'],
            'minorversion' => $libdata['minorVersion']
        );

        $libraries = $DB->get_records('h5p_libraries', $params, 'patchversion DESC', 'id',
            0, 1);

        if (!$library = reset($libraries)) {
            debugging('The library "' . $libfoldername . '" does not exist.', DEBUG_DEVELOPER);

            return;
        }

        $context = \context_system::instance();

        return \moodle_url::make_pluginfile_url($context->id, 'core_h5p', 'libraries',
            $library->id, '/' . $libraryfilepath . '/', $filename)->out();
    }

    /**
     * Get the Path to the last uploaded h5p.
     * Implements getUploadedH5PFolderPath.
     *
     * @param string $setpath The path to the folder of the last uploaded h5p
     * @return string Path to the folder where the last uploaded h5p for this session is located
     */
    public function getUploadedH5pFolderPath($setpath = null) {
        if ($setpath !== null) {
            $this->lastuploadedfolder = $setpath;
        }

        if (!isset($this->lastuploadedfolder)) {
            throw new \coding_exception('Using getUploadedH5pFolderPath() before path is set');
        }

        return $this->lastuploadedfolder;
    }

    /**
     * Get the path to the last uploaded h5p file.
     * Implements getUploadedH5PPath.
     *
     * @param string $setpath The path to the last uploaded h5p
     * @return string Path to the last uploaded h5p
     */
    public function getUploadedH5pPath($setpath = null) {
        if ($setpath !== null) {
            $this->lastuploadedfile = $setpath;
        }

        if (!isset($this->lastuploadedfile)) {
            throw new \coding_exception('Using getUploadedH5pPath() before path is set');
        }

        return $this->lastuploadedfile;
    }

    /**
     * Load addon libraries.
     * Implements loadAddons.
     *
     * @return array The array containing the addon libraries
     */
    public function loadAddons() {
        global $DB;

        $addons = array();

        $records = $DB->get_records_sql(
                "SELECT l1.id AS library_id,
                            l1.machinename AS machine_name,
                            l1.majorversion AS major_version,
                            l1.minorversion AS minor_version,
                            l1.patchversion AS patch_version,
                            l1.addto AS add_to,
                            l1.preloadedjs AS preloaded_js,
                            l1.preloadedcss AS preloaded_css
                       FROM {h5p_libraries} l1
                  LEFT JOIN {h5p_libraries} l2
                         ON l1.machinename = l2.machinename
                        AND (l1.majorversion < l2.majorversion
                             OR (l1.majorversion = l2.majorversion
                                 AND l1.minorversion < l2.minorversion))
                      WHERE l1.addto IS NOT NULL
                        AND l2.machinename IS NULL");

        // NOTE: These are treated as library objects but are missing the following properties:
        // title, droplibrarycss, fullscreen, runnable, semantics.

        // Extract num from records.
        foreach ($records as $addon) {
            $addons[] = \H5PCore::snakeToCamel($addon);
        }

        return $addons;
    }

    /**
     * Load config for libraries.
     * Implements getLibraryConfig.
     *
     * @param array|null $libraries List of libraries
     * @return array|null The library config if it exists, null otherwise
     */
    public function getLibraryConfig($libraries = null) {
        global $CFG;
        return isset($CFG->core_h5p_library_config) ? $CFG->core_h5p_library_config : null;
    }

    /**
     * Get a list of the current installed libraries.
     * Implements loadLibraries.
     *
     * @return array Associative array containing one entry per machine name.
     *               For each machineName there is a list of libraries(with different versions).
     */
    public function loadLibraries() {
        global $DB;

        $results = $DB->get_records('h5p_libraries', [], 'title ASC, majorversion ASC, minorversion ASC',
            'id, machinename AS machine_name, majorversion AS major_version, minorversion AS minor_version,
            patchversion AS patch_version, runnable, title');

        $libraries = array();
        foreach ($results as $library) {
            $libraries[$library->machine_name][] = $library;
        }

        return $libraries;
    }

    /**
     * Returns the URL to the library admin page.
     * Implements getAdminUrl.
     *
     * @return string URL to admin page
     */
    public function getAdminUrl() {
        // Not supported.
    }

    /**
     * Return the library's ID.
     * Implements getLibraryId.
     *
     * @param string $machinename The librarys machine name
     * @param string $majorversion Major version number for library (optional)
     * @param string $minorversion Minor version number for library (optional)
     * @return int|bool Identifier, or false if non-existent
     */
    public function getLibraryId($machinename, $majorversion = null, $minorversion = null) {
        global $DB;

        $params = array(
            'machinename' => $machinename
        );

        if ($majorversion !== null) {
            $params['majorversion'] = $majorversion;
        }

        if ($minorversion !== null) {
            $params['minorversion'] = $minorversion;
        }

        $libraries = $DB->get_records('h5p_libraries', $params,
            'majorversion DESC, minorversion DESC, patchversion DESC', 'id', 0, 1);

        // Get the latest version which matches the input parameters.
        if ($libraries) {
            $library = reset($libraries);
            return $library->id ?? false;
        }

        return false;
    }

    /**
     * Get file extension whitelist.
     * Implements getWhitelist.
     *
     * The default extension list is part of h5p, but admins should be allowed to modify it.
     *
     * @param boolean $islibrary TRUE if this is the whitelist for a library. FALSE if it is the whitelist
     *                           for the content folder we are getting.
     * @param string $defaultcontentwhitelist A string of file extensions separated by whitespace.
     * @param string $defaultlibrarywhitelist A string of file extensions separated by whitespace.
     * @return string A string containing the allowed file extensions separated by whitespace.
     */
    public function getWhitelist($islibrary, $defaultcontentwhitelist, $defaultlibrarywhitelist) {
        return $defaultcontentwhitelist . ($islibrary ? ' ' . $defaultlibrarywhitelist : '');
    }

    /**
     * Is the library a patched version of an existing library?
     * Implements isPatchedLibrary.
     *
     * @param array $library An associative array containing:
     *                       - machineName: The library machine name
     *                       - majorVersion: The librarys major version
     *                       - minorVersion: The librarys minor version
     *                       - patchVersion: The librarys patch version
     * @return boolean TRUE if the library is a patched version of an existing library FALSE otherwise
     */
    public function isPatchedLibrary($library) {
        global $DB;

        $sql = "SELECT id
                  FROM {h5p_libraries}
                 WHERE machinename = :machinename
                   AND majorversion = :majorversion
                   AND minorversion = :minorversion
                   AND patchversion < :patchversion";

        $library = $DB->get_records_sql(
            $sql,
            array(
                'machinename' => $library['machineName'],
                'majorversion' => $library['majorVersion'],
                'minorversion' => $library['minorVersion'],
                'patchversion' => $library['patchVersion']
            ),
            0,
            1
        );

        return !empty($library);
    }

    /**
     * Is H5P in development mode?
     * Implements isInDevMode.
     *
     * @return boolean TRUE if H5P development mode is active FALSE otherwise
     */
    public function isInDevMode() {
        return false; // Not supported (Files in moodle not editable).
    }

    /**
     * Is the current user allowed to update libraries?
     * Implements mayUpdateLibraries.
     *
     * @return boolean TRUE if the user is allowed to update libraries,
     *                 FALSE if the user is not allowed to update libraries.
     */
    public function mayUpdateLibraries() {
        return helper::can_update_library($this->get_file());
    }

    /**
     * Get the .h5p file.
     *
     * @return stored_file The .h5p file.
     */
    public function get_file(): \stored_file {
        if (!isset($this->file)) {
            throw new \coding_exception('Using get_file() before file is set');
        }

        return $this->file;
    }

    /**
     * Set the .h5p file.
     *
     * @param  stored_file $file The .h5p file.
     */
    public function set_file(\stored_file $file): void {
        $this->file = $file;
    }

    /**
     * Store data about a library.
     * Implements saveLibraryData.
     *
     * Also fills in the libraryId in the libraryData object if the object is new.
     *
     * @param array $librarydata Associative array containing:
     *                           - libraryId: The id of the library if it is an existing library
     *                           - title: The library's name
     *                           - machineName: The library machineName
     *                           - majorVersion: The library's majorVersion
     *                           - minorVersion: The library's minorVersion
     *                           - patchVersion: The library's patchVersion
     *                           - runnable: 1 if the library is a content type, 0 otherwise
     *                           - fullscreen(optional): 1 if the library supports fullscreen, 0 otherwise
     *                           - embedtypes: list of supported embed types
     *                           - preloadedJs(optional): list of associative arrays containing:
     *                             - path: path to a js file relative to the library root folder
     *                           - preloadedCss(optional): list of associative arrays containing:
     *                             - path: path to css file relative to the library root folder
     *                           - dropLibraryCss(optional): list of associative arrays containing:
     *                             - machineName: machine name for the librarys that are to drop their css
     *                           - semantics(optional): Json describing the content structure for the library
     * @param bool $new Whether it is a new or existing library.
     */
    public function saveLibraryData(&$librarydata, $new = true) {
        global $DB;

        // Some special properties needs some checking and converting before they can be saved.
        $preloadedjs = $this->library_parameter_values_to_csv($librarydata, 'preloadedJs', 'path');
        $preloadedcss = $this->library_parameter_values_to_csv($librarydata, 'preloadedCss', 'path');
        $droplibrarycss = $this->library_parameter_values_to_csv($librarydata, 'dropLibraryCss', 'machineName');

        if (!isset($librarydata['semantics'])) {
            $librarydata['semantics'] = '';
        }
        if (!isset($librarydata['fullscreen'])) {
            $librarydata['fullscreen'] = 0;
        }
        $embedtypes = '';
        if (isset($librarydata['embedTypes'])) {
            $embedtypes = implode(', ', $librarydata['embedTypes']);
        }

        $library = (object) array(
            'title' => $librarydata['title'],
            'machinename' => $librarydata['machineName'],
            'majorversion' => $librarydata['majorVersion'],
            'minorversion' => $librarydata['minorVersion'],
            'patchversion' => $librarydata['patchVersion'],
            'runnable' => $librarydata['runnable'],
            'fullscreen' => $librarydata['fullscreen'],
            'embedtypes' => $embedtypes,
            'preloadedjs' => $preloadedjs,
            'preloadedcss' => $preloadedcss,
            'droplibrarycss' => $droplibrarycss,
            'semantics' => $librarydata['semantics'],
            'addto' => isset($librarydata['addTo']) ? json_encode($librarydata['addTo']) : null,
            'coremajor' => isset($librarydata['coreApi']['majorVersion']) ? $librarydata['coreApi']['majorVersion'] : null,
            'coreminor' => isset($librarydata['coreApi']['majorVersion']) ? $librarydata['coreApi']['minorVersion'] : null,
        );

        if ($new) {
            // Create new library and keep track of id.
            $library->id = $DB->insert_record('h5p_libraries', $library);
            $librarydata['libraryId'] = $library->id;
        } else {
            // Update library data.
            $library->id = $librarydata['libraryId'];
            // Save library data.
            $DB->update_record('h5p_libraries', $library);
            // Remove old dependencies.
            $this->deleteLibraryDependencies($librarydata['libraryId']);
        }
    }

    /**
     * Insert new content.
     * Implements insertContent.
     *
     * @param array $content An associative array containing:
     *                       - id: The content id
     *                       - params: The content in json format
     *                       - library: An associative array containing:
     *                         - libraryId: The id of the main library for this content
     *                       - disable: H5P Button display options
     *                       - pathnamehash: The pathnamehash linking the record with the entry in the mdl_files table
     *                       - contenthash: The contenthash linking the record with the entry in the mdl_files table
     * @param int $contentmainid Main id for the content if this is a system that supports versions
     * @return int The ID of the newly inserted content
     */
    public function insertContent($content, $contentmainid = null) {
        return $this->updateContent($content);
    }

    /**
     * Update old content or insert new content.
     * Implements updateContent.
     *
     * @param array $content An associative array containing:
     *                       - id: The content id
     *                       - params: The content in json format
     *                       - library: An associative array containing:
     *                         - libraryId: The id of the main library for this content
     *                       - disable: H5P Button display options
     *                       - pathnamehash: The pathnamehash linking the record with the entry in the mdl_files table
     *                       - contenthash: The contenthash linking the record with the entry in the mdl_files table
     * @param int $contentmainid Main id for the content if this is a system that supports versions
     * @return int The ID of the newly inserted or updated content
     */
    public function updateContent($content, $contentmainid = null) {
        global $DB;

        if (!isset($content['pathnamehash'])) {
            $content['pathnamehash'] = '';
        }

        if (!isset($content['contenthash'])) {
            $content['contenthash'] = '';
        }

        // If the libraryid declared in the package is empty, get the latest version.
        if (empty($content['library']['libraryId'])) {
            $mainlibrary = $this->get_latest_library_version($content['library']['machineName']);
            if (empty($mainlibrary)) {
                // Raise an error if the main library is not defined and the latest version doesn't exist.
                $message = $this->t('Missing required library @library', ['@library' => $content['library']['machineName']]);
                $this->setErrorMessage($message, 'missing-required-library');
                return false;
            }
            $content['library']['libraryId'] = $mainlibrary->id;
        }

        $data = [
            'jsoncontent' => $content['params'],
            'displayoptions' => $content['disable'],
            'mainlibraryid' => $content['library']['libraryId'],
            'timemodified' => time(),
            'filtered' => null,
            'pathnamehash' => $content['pathnamehash'],
            'contenthash' => $content['contenthash']
        ];

        if (!isset($content['id'])) {
            $data['timecreated'] = $data['timemodified'];
            $id = $DB->insert_record('h5p', $data);
        } else {
            $id = $data['id'] = $content['id'];
            $DB->update_record('h5p', $data);
        }

        return $id;
    }

    /**
     * Resets marked user data for the given content.
     * Implements resetContentUserData.
     *
     * @param int $contentid The h5p content id
     */
    public function resetContentUserData($contentid) {
        // Currently, we do not store user data for a content.
    }

    /**
     * Save what libraries a library is depending on.
     * Implements saveLibraryDependencies.
     *
     * @param int $libraryid Library Id for the library we're saving dependencies for
     * @param array $dependencies List of dependencies as associative arrays containing:
     *                            - machineName: The library machineName
     *                            - majorVersion: The library's majorVersion
     *                            - minorVersion: The library's minorVersion
     * @param string $dependencytype The type of dependency
     */
    public function saveLibraryDependencies($libraryid, $dependencies, $dependencytype) {
        global $DB;

        foreach ($dependencies as $dependency) {
            // Find dependency library.
            $dependencylibrary = $DB->get_record('h5p_libraries',
                array(
                    'machinename' => $dependency['machineName'],
                    'majorversion' => $dependency['majorVersion'],
                    'minorversion' => $dependency['minorVersion']
                )
            );

            // Create relation.
            $DB->insert_record('h5p_library_dependencies', array(
                'libraryid' => $libraryid,
                'requiredlibraryid' => $dependencylibrary->id,
                'dependencytype' => $dependencytype
            ));
        }
    }

    /**
     * Give an H5P the same library dependencies as a given H5P.
     * Implements copyLibraryUsage.
     *
     * @param int $contentid Id identifying the content
     * @param int $copyfromid Id identifying the content to be copied
     * @param int $contentmainid Main id for the content, typically used in frameworks
     */
    public function copyLibraryUsage($contentid, $copyfromid, $contentmainid = null) {
        // Currently not being called.
    }

    /**
     * Deletes content data.
     * Implements deleteContentData.
     *
     * @param int $contentid Id identifying the content
     */
    public function deleteContentData($contentid) {
        global $DB;

        // Remove content.
        $DB->delete_records('h5p', array('id' => $contentid));

        // Remove content library dependencies.
        $this->deleteLibraryUsage($contentid);
    }

    /**
     * Delete what libraries a content item is using.
     * Implements deleteLibraryUsage.
     *
     * @param int $contentid Content Id of the content we'll be deleting library usage for
     */
    public function deleteLibraryUsage($contentid) {
        global $DB;

        $DB->delete_records('h5p_contents_libraries', array('h5pid' => $contentid));
    }

    /**
     * Saves what libraries the content uses.
     * Implements saveLibraryUsage.
     *
     * @param int $contentid Id identifying the content
     * @param array $librariesinuse List of libraries the content uses
     */
    public function saveLibraryUsage($contentid, $librariesinuse) {
        global $DB;

        $droplibrarycsslist = array();
        foreach ($librariesinuse as $dependency) {
            if (!empty($dependency['library']['dropLibraryCss'])) {
                $droplibrarycsslist = array_merge($droplibrarycsslist,
                        explode(', ', $dependency['library']['dropLibraryCss']));
            }
        }

        foreach ($librariesinuse as $dependency) {
            $dropcss = in_array($dependency['library']['machineName'], $droplibrarycsslist) ? 1 : 0;
            $DB->insert_record('h5p_contents_libraries', array(
                'h5pid' => $contentid,
                'libraryid' => $dependency['library']['libraryId'],
                'dependencytype' => $dependency['type'],
                'dropcss' => $dropcss,
                'weight' => $dependency['weight']
            ));
        }
    }

    /**
     * Get number of content/nodes using a library, and the number of dependencies to other libraries.
     * Implements getLibraryUsage.
     *
     * @param int $id Library identifier
     * @param boolean $skipcontent Optional. Set as true to get number of content instances for library
     * @return array The array contains two elements, keyed by 'content' and 'libraries'.
     *               Each element contains a number
     */
    public function getLibraryUsage($id, $skipcontent = false) {
        global $DB;

        if ($skipcontent) {
            $content = -1;
        } else {
            $sql = "SELECT COUNT(distinct c.id)
                      FROM {h5p_libraries} l
                      JOIN {h5p_contents_libraries} cl ON l.id = cl.libraryid
                      JOIN {h5p} c ON cl.h5pid = c.id
                     WHERE l.id = :libraryid";

            $sqlargs = array(
                'libraryid' => $id
            );

            $content = $DB->count_records_sql($sql, $sqlargs);
        }

        $libraries = $DB->count_records('h5p_library_dependencies', ['requiredlibraryid' => $id]);

        return array(
            'content' => $content,
            'libraries' => $libraries,
        );
    }

    /**
     * Loads a library.
     * Implements loadLibrary.
     *
     * @param string $machinename The library's machine name
     * @param int $majorversion The library's major version
     * @param int $minorversion The library's minor version
     * @return array|bool Returns FALSE if the library does not exist
     *                     Otherwise an associative array containing:
     *                     - libraryId: The id of the library if it is an existing library,
     *                     - title: The library's name,
     *                     - machineName: The library machineName
     *                     - majorVersion: The library's majorVersion
     *                     - minorVersion: The library's minorVersion
     *                     - patchVersion: The library's patchVersion
     *                     - runnable: 1 if the library is a content type, 0 otherwise
     *                     - fullscreen: 1 if the library supports fullscreen, 0 otherwise
     *                     - embedTypes: list of supported embed types
     *                     - preloadedJs: comma separated string with js file paths
     *                     - preloadedCss: comma separated sting with css file paths
     *                     - dropLibraryCss: list of associative arrays containing:
     *                       - machineName: machine name for the librarys that are to drop their css
     *                     - semantics: Json describing the content structure for the library
     *                     - preloadedDependencies(optional): list of associative arrays containing:
     *                       - machineName: Machine name for a library this library is depending on
     *                       - majorVersion: Major version for a library this library is depending on
     *                       - minorVersion: Minor for a library this library is depending on
     *                     - dynamicDependencies(optional): list of associative arrays containing:
     *                       - machineName: Machine name for a library this library is depending on
     *                       - majorVersion: Major version for a library this library is depending on
     *                       - minorVersion: Minor for a library this library is depending on
     */
    public function loadLibrary($machinename, $majorversion, $minorversion) {
        global $DB;

        $library = $DB->get_record('h5p_libraries', array(
            'machinename' => $machinename,
            'majorversion' => $majorversion,
            'minorversion' => $minorversion
        ));

        if (!$library) {
            return false;
        }

        $librarydata = array(
            'libraryId' => $library->id,
            'title' => $library->title,
            'machineName' => $library->machinename,
            'majorVersion' => $library->majorversion,
            'minorVersion' => $library->minorversion,
            'patchVersion' => $library->patchversion,
            'runnable' => $library->runnable,
            'fullscreen' => $library->fullscreen,
            'embedTypes' => $library->embedtypes,
            'preloadedJs' => $library->preloadedjs,
            'preloadedCss' => $library->preloadedcss,
            'dropLibraryCss' => $library->droplibrarycss,
            'semantics'     => $library->semantics
        );

        $sql = 'SELECT hl.id, hl.machinename, hl.majorversion, hl.minorversion, hll.dependencytype
                  FROM {h5p_library_dependencies} hll
                  JOIN {h5p_libraries} hl ON hll.requiredlibraryid = hl.id
                 WHERE hll.libraryid = :libraryid
              ORDER BY hl.id ASC';

        $sqlargs = array(
            'libraryid' => $library->id
        );

        $dependencies = $DB->get_records_sql($sql, $sqlargs);

        foreach ($dependencies as $dependency) {
            $librarydata[$dependency->dependencytype . 'Dependencies'][] = array(
                'machineName' => $dependency->machinename,
                'majorVersion' => $dependency->majorversion,
                'minorVersion' => $dependency->minorversion
            );
        }

        return $librarydata;
    }

    /**
     * Loads library semantics.
     * Implements loadLibrarySemantics.
     *
     * @param string $name Machine name for the library
     * @param int $majorversion The library's major version
     * @param int $minorversion The library's minor version
     * @return string The library's semantics as json
     */
    public function loadLibrarySemantics($name, $majorversion, $minorversion) {
        global $DB;

        $semantics = $DB->get_field('h5p_libraries', 'semantics',
            array(
                'machinename' => $name,
                'majorversion' => $majorversion,
                'minorversion' => $minorversion
            )
        );

        return ($semantics === false ? null : $semantics);
    }

    /**
     * Makes it possible to alter the semantics, adding custom fields, etc.
     * Implements alterLibrarySemantics.
     *
     * @param array $semantics Associative array representing the semantics
     * @param string $name The library's machine name
     * @param int $majorversion The library's major version
     * @param int $minorversion The library's minor version
     */
    public function alterLibrarySemantics(&$semantics, $name, $majorversion, $minorversion) {
        global $DB;

        $library = $DB->get_record('h5p_libraries',
            array(
                'machinename' => $name,
                'majorversion' => $majorversion,
                'minorversion' => $minorversion,
            )
        );

        if ($library) {
            $library->semantics = json_encode($semantics);
            $DB->update_record('h5p_libraries', $library);
        }
    }

    /**
     * Delete all dependencies belonging to given library.
     * Implements deleteLibraryDependencies.
     *
     * @param int $libraryid Library identifier
     */
    public function deleteLibraryDependencies($libraryid) {
        global $DB;

        $DB->delete_records('h5p_library_dependencies', array('libraryid' => $libraryid));
    }

    /**
     * Start an atomic operation against the dependency storage.
     * Implements lockDependencyStorage.
     */
    public function lockDependencyStorage() {
        // Library development mode not supported.
    }

    /**
     * Start an atomic operation against the dependency storage.
     * Implements unlockDependencyStorage.
     */
    public function unlockDependencyStorage() {
        // Library development mode not supported.
    }

    /**
     * Delete a library from database and file system.
     * Implements deleteLibrary.
     *
     * @param stdClass $library Library object with id, name, major version and minor version
     */
    public function deleteLibrary($library) {
        global $DB;

        $fs = new \core_h5p\file_storage();
        // Delete the library from the file system.
        $fs->delete_library(array('libraryId' => $library->id));
        // Delete also the cache assets to rebuild them next time.
        $this->deleteCachedAssets($library->id);

        // Remove library data from database.
        $DB->delete_records('h5p_library_dependencies', array('libraryid' => $library->id));
        $DB->delete_records('h5p_libraries', array('id' => $library->id));
    }

    /**
     * Load content.
     * Implements loadContent.
     *
     * @param int $id Content identifier
     * @return array Associative array containing:
     *               - id: Identifier for the content
     *               - params: json content as string
     *               - embedType: list of supported embed types
     *               - disable: H5P Button display options
     *               - title: H5P content title
     *               - slug: Human readable content identifier that is unique
     *               - libraryId: Id for the main library
     *               - libraryName: The library machine name
     *               - libraryMajorVersion: The library's majorVersion
     *               - libraryMinorVersion: The library's minorVersion
     *               - libraryEmbedTypes: CSV of the main library's embed types
     *               - libraryFullscreen: 1 if fullscreen is supported. 0 otherwise
     *               - metadata: The content's metadata
     */
    public function loadContent($id) {
        global $DB;

        $sql = "SELECT hc.id, hc.jsoncontent, hc.displayoptions, hl.id AS libraryid,
                       hl.machinename, hl.title, hl.majorversion, hl.minorversion, hl.fullscreen,
                       hl.embedtypes, hl.semantics, hc.filtered
                  FROM {h5p} hc
                  JOIN {h5p_libraries} hl ON hl.id = hc.mainlibraryid
                 WHERE hc.id = :h5pid";

        $sqlargs = array(
            'h5pid' => $id
        );

        $data = $DB->get_record_sql($sql, $sqlargs);

        // Return null if not found.
        if ($data === false) {
            return null;
        }

        // Some databases do not support camelCase, so we need to manually
        // map the values to the camelCase names used by the H5P core.
        $content = array(
            'id' => $data->id,
            'params' => $data->jsoncontent,
            // It has been decided that the embedtype will be always set to 'iframe' (at least for now) because the 'div'
            // may cause conflicts with CSS and JS in some cases.
            'embedType' => 'iframe',
            'disable' => $data->displayoptions,
            'title' => $data->title,
            'slug' => \H5PCore::slugify($data->title) . '-' . $data->id,
            'filtered' => $data->filtered,
            'libraryId' => $data->libraryid,
            'libraryName' => $data->machinename,
            'libraryMajorVersion' => $data->majorversion,
            'libraryMinorVersion' => $data->minorversion,
            'libraryEmbedTypes' => $data->embedtypes,
            'libraryFullscreen' => $data->fullscreen,
            'metadata' => ''
        );

        return $content;
    }

    /**
     * Load dependencies for the given content of the given type.
     * Implements loadContentDependencies.
     *
     * @param int $id Content identifier
     * @param int $type The dependency type
     * @return array List of associative arrays containing:
     *               - libraryId: The id of the library if it is an existing library
     *               - machineName: The library machineName
     *               - majorVersion: The library's majorVersion
     *               - minorVersion: The library's minorVersion
     *               - patchVersion: The library's patchVersion
     *               - preloadedJs(optional): comma separated string with js file paths
     *               - preloadedCss(optional): comma separated sting with css file paths
     *               - dropCss(optional): csv of machine names
     *               - dependencyType: The dependency type
     */
    public function loadContentDependencies($id, $type = null) {
        global $DB;

        $query = "SELECT hcl.id AS unidepid, hl.id AS library_id, hl.machinename AS machine_name,
                         hl.majorversion AS major_version, hl.minorversion AS minor_version,
                         hl.patchversion AS patch_version, hl.preloadedcss AS preloaded_css,
                         hl.preloadedjs AS preloaded_js, hcl.dropcss AS drop_css,
                         hcl.dependencytype as dependency_type
                    FROM {h5p_contents_libraries} hcl
                    JOIN {h5p_libraries} hl ON hcl.libraryid = hl.id
                   WHERE hcl.h5pid = :h5pid";
        $queryargs = array(
            'h5pid' => $id
        );

        if ($type !== null) {
            $query .= " AND hcl.dependencytype = :dependencytype";
            $queryargs['dependencytype'] = $type;
        }

        $query .= " ORDER BY hcl.weight";
        $data = $DB->get_records_sql($query, $queryargs);

        $dependencies = array();
        foreach ($data as $dependency) {
            unset($dependency->unidepid);
            $dependencies[$dependency->machine_name] = \H5PCore::snakeToCamel($dependency);
        }

        return $dependencies;
    }

    /**
     * Get stored setting.
     * Implements getOption.
     *
     * @param string $name Identifier for the setting
     * @param string $default Optional default value if settings is not set
     * @return mixed Return  Whatever has been stored as the setting
     */
    public function getOption($name, $default = false) {
        if ($name == core::DISPLAY_OPTION_DOWNLOAD || $name == core::DISPLAY_OPTION_EMBED) {
            // For now, the download and the embed displayoptions are disabled by default, so only will be rendered when
            // defined in the displayoptions DB field.
            // This check should be removed if they are added as new H5P settings, to let admins to define the default value.
            return \H5PDisplayOptionBehaviour::CONTROLLED_BY_AUTHOR_DEFAULT_OFF;
        }

        $value = get_config('core_h5p', $name);
        if ($value === false) {
            return $default;
        }
        return $value;
    }

    /**
     * Stores the given setting.
     * For example when did we last check h5p.org for updates to our libraries.
     * Implements setOption.
     *
     * @param string $name Identifier for the setting
     * @param mixed $value Data Whatever we want to store as the setting
     */
    public function setOption($name, $value) {
        set_config($name, $value, 'core_h5p');
    }

    /**
     * This will update selected fields on the given content.
     * Implements updateContentFields().
     *
     * @param int $id Content identifier
     * @param array $fields Content fields, e.g. filtered
     */
    public function updateContentFields($id, $fields) {
        global $DB;

        $content = new \stdClass();
        $content->id = $id;

        foreach ($fields as $name => $value) {
            // Skip 'slug' as it currently does not exist in the h5p content table.
            if ($name == 'slug') {
                continue;
            }

            $content->$name = $value;
        }

        $DB->update_record('h5p', $content);
    }

    /**
     * Will clear filtered params for all the content that uses the specified.
     * libraries. This means that the content dependencies will have to be rebuilt and the parameters re-filtered.
     * Implements clearFilteredParameters().
     *
     * @param array $libraryids Array of library ids
     */
    public function clearFilteredParameters($libraryids) {
        global $DB;

        if (empty($libraryids)) {
            return;
        }

        list($insql, $inparams) = $DB->get_in_or_equal($libraryids);

        $DB->set_field_select('h5p', 'filtered', null,
            "mainlibraryid $insql", $inparams);
    }

    /**
     * Get number of contents that has to get their content dependencies rebuilt.
     * and parameters re-filtered.
     * Implements getNumNotFiltered().
     *
     * @return int The number of contents that has to get their content dependencies rebuilt
     *             and parameters re-filtered
     */
    public function getNumNotFiltered() {
        global $DB;

        $sql = "SELECT COUNT(id)
                  FROM {h5p}
                 WHERE " . $DB->sql_compare_text('filtered') . " IS NULL";

        return $DB->count_records_sql($sql);
    }

    /**
     * Get number of contents using library as main library.
     * Implements getNumContent().
     *
     * @param int $libraryid The library ID
     * @param array $skip The array of h5p content ID's that should be ignored
     * @return int The number of contents using library as main library
     */
    public function getNumContent($libraryid, $skip = null) {
        global $DB;

        $notinsql = '';
        $params = array();

        if (!empty($skip)) {
            list($sql, $params) = $DB->get_in_or_equal($skip, SQL_PARAMS_NAMED, 'param', false);
            $notinsql = " AND id {$sql}";
        }

        $sql = "SELECT COUNT(id)
                  FROM {h5p}
                 WHERE mainlibraryid = :libraryid {$notinsql}";

        $params['libraryid'] = $libraryid;

        return $DB->count_records_sql($sql, $params);
    }

    /**
     * Determines if content slug is used.
     * Implements isContentSlugAvailable.
     *
     * @param string $slug The content slug
     * @return boolean Whether the content slug is used
     */
    public function isContentSlugAvailable($slug) {
        // By default the slug should be available as it's currently generated as a unique
        // value for each h5p content (not stored in the h5p table).
        return true;
    }

    /**
     * Generates statistics from the event log per library.
     * Implements getLibraryStats.
     *
     * @param string $type Type of event to generate stats for
     * @return array Number values indexed by library name and version
     */
    public function getLibraryStats($type) {
        // Event logs are not being stored.
    }

    /**
     * Aggregate the current number of H5P authors.
     * Implements getNumAuthors.
     *
     * @return int The current number of H5P authors
     */
    public function getNumAuthors() {
        // Currently, H5P authors are not being stored.
    }

    /**
     * Stores hash keys for cached assets, aggregated JavaScripts and
     * stylesheets, and connects it to libraries so that we know which cache file
     * to delete when a library is updated.
     * Implements saveCachedAssets.
     *
     * @param string $key Hash key for the given libraries
     * @param array $libraries List of dependencies(libraries) used to create the key
     */
    public function saveCachedAssets($key, $libraries) {
        global $DB;

        foreach ($libraries as $library) {
            $cachedasset = new \stdClass();
            $cachedasset->libraryid = $library['libraryId'];
            $cachedasset->hash = $key;

            $DB->insert_record('h5p_libraries_cachedassets', $cachedasset);
        }
    }

    /**
     * Locate hash keys for given library and delete them.
     * Used when cache file are deleted.
     * Implements deleteCachedAssets.
     *
     * @param int $libraryid Library identifier
     * @return array List of hash keys removed
     */
    public function deleteCachedAssets($libraryid) {
        global $DB;

        // Get all the keys so we can remove the files.
        $results = $DB->get_records('h5p_libraries_cachedassets', ['libraryid' => $libraryid]);

        $hashes = array_map(function($result) {
            return $result->hash;
        }, $results);

        if (!empty($hashes)) {
            list($sql, $params) = $DB->get_in_or_equal($hashes, SQL_PARAMS_NAMED);
            // Remove all invalid keys.
            $DB->delete_records_select('h5p_libraries_cachedassets', 'hash ' . $sql, $params);

            // Remove also the cachedassets files.
            $fs = new file_storage();
            $fs->deleteCachedAssets($hashes);
        }

        return $hashes;
    }

    /**
     * Get the amount of content items associated to a library.
     * Implements getLibraryContentCount.
     *
     * return array The number of content items associated to a library
     */
    public function getLibraryContentCount() {
        global $DB;

        $contentcount = array();

        $sql = "SELECT h.mainlibraryid,
                       l.machinename,
                       l.majorversion,
                       l.minorversion,
                       COUNT(h.id) AS count
                  FROM {h5p} h
             LEFT JOIN {h5p_libraries} l
                    ON h.mainlibraryid = l.id
              GROUP BY h.mainlibraryid, l.machinename, l.majorversion, l.minorversion";

        // Count content using the same content type.
        $res = $DB->get_records_sql($sql);

        // Extract results.
        foreach ($res as $lib) {
            $contentcount["{$lib->machinename} {$lib->majorversion}.{$lib->minorversion}"] = $lib->count;
        }

        return $contentcount;
    }

    /**
     * Will trigger after the export file is created.
     * Implements afterExportCreated.
     *
     * @param array $content The content
     * @param string $filename The file name
     */
    public function afterExportCreated($content, $filename) {
        // Not being used.
    }

    /**
     * Check whether a user has permissions to execute an action, such as embed H5P content.
     * Implements hasPermission.
     *
     * @param  \H5PPermission $permission Permission type
     * @param  int $id Id need by platform to determine permission
     * @return boolean true if the user can execute the action defined in $permission; false otherwise
     */
    public function hasPermission($permission, $id = null) {
        // H5P capabilities have not been introduced.
    }

    /**
     * Replaces existing content type cache with the one passed in.
     * Implements replaceContentTypeCache.
     *
     * @param object $contenttypecache Json with an array called 'libraries' containing the new content type cache
     *                                 that should replace the old one
     */
    public function replaceContentTypeCache($contenttypecache) {
        // Currently, content type caches are not being stored.
    }

    /**
     * Checks if the given library has a higher version.
     * Implements libraryHasUpgrade.
     *
     * @param array $library An associative array containing:
     *                       - machineName: The library machineName
     *                       - majorVersion: The library's majorVersion
     *                       - minorVersion: The library's minorVersion
     * @return boolean Whether the library has a higher version
     */
    public function libraryHasUpgrade($library) {
        global $DB;

        $sql = "SELECT id
                  FROM {h5p_libraries}
                 WHERE machinename = :machinename
                   AND (majorversion > :majorversion1
                    OR (majorversion = :majorversion2 AND minorversion > :minorversion))";

        $results = $DB->get_records_sql(
            $sql,
            array(
                'machinename' => $library['machineName'],
                'majorversion1' => $library['majorVersion'],
                'majorversion2' => $library['majorVersion'],
                'minorversion' => $library['minorVersion']
            ),
            0,
            1
        );

        return !empty($results);
    }

    /**
     * Get current H5P language code.
     *
     * @return string Language Code
     */
    public static function get_language() {
        static $map;

        if (empty($map)) {
            // Create mapping for "converting" language codes.
            $map = array(
                'no' => 'nb'
            );
        }

        // Get current language in Moodle.
        $language = str_replace('_', '-', strtolower(\current_language()));

        // Try to map.
        return $map[$language] ?? $language;
    }

    /**
     * Store messages until they can be printed to the current user.
     *
     * @param string $type Type of messages, e.g. 'info', 'error', etc
     * @param string $newmessage The message
     * @param string $code The message code
     */
    private function set_message(string $type, string $newmessage = null, string $code = null) {
        global $SESSION;

        // We expect to get out an array of strings when getting info
        // and an array of objects when getting errors for consistency across platforms.
        // This implementation should be improved for consistency across the data type returned here.
        if ($type === 'error') {
            $SESSION->core_h5p_messages[$type][] = (object) array(
                'code' => $code,
                'message' => $newmessage
            );
        } else {
            $SESSION->core_h5p_messages[$type][] = $newmessage;
        }
    }

    /**
     * Convert list of library parameter values to csv.
     *
     * @param array $librarydata Library data as found in library.json files
     * @param string $key Key that should be found in $librarydata
     * @param string $searchparam The library parameter (Default: 'path')
     * @return string Library parameter values separated by ', '
     */
    private function library_parameter_values_to_csv(array $librarydata, string $key, string $searchparam = 'path'): string {
        if (isset($librarydata[$key])) {
            $parametervalues = array();
            foreach ($librarydata[$key] as $file) {
                foreach ($file as $index => $value) {
                    if ($index === $searchparam) {
                        $parametervalues[] = $value;
                    }
                }
            }
            return implode(', ', $parametervalues);
        }
        return '';
    }

    /**
     * Get the latest library version.
     *
     * @param  string $machinename The library's machine name
     * @return stdClass|null An object with the latest library version
     */
    public function get_latest_library_version(string $machinename): ?\stdClass {
        global $DB;

        $libraries = $DB->get_records('h5p_libraries', ['machinename' => $machinename],
            'majorversion DESC, minorversion DESC, patchversion DESC', '*', 0, 1);
        if ($libraries) {
            return reset($libraries);
        }

        return null;
    }
}
