<?php
// This file keeps track of upgrades to
// the glossary module
//
// Sometimes, changes between versions involve
// alterations to database structures and other
// major things that may break installations.
//
// The upgrade function in this file will attempt
// to perform all the necessary actions to upgrade
// your older installation to the current version.
//
// If there's something it cannot do itself, it
// will tell you what you need to do.
//
// The commands in here will all be database-neutral,
// using the methods of database_manager class
//
// Please do not forget to use upgrade_set_timeout()
// before any action that may take longer time to finish.

function xmldb_glossary_upgrade($oldversion) {
    global $DB;


<     // Automatically generated Moodle v3.5.0 release upgrade line.
<     // Put any upgrade step following this.
< 
<     if ($oldversion < 2018051401) {
< 
<         // Fetch the module ID for the glossary module.
<         $glossarymoduleid = $DB->get_field('modules', 'id', ['name' => 'glossary']);
< 
<         // Get id of section 1 on the frontpage course.
<         $fpsection1 = $DB->get_field('course_sections', 'id', ['course' => SITEID, 'section' => 1]);
< 
<         // Fetch sections for the frontpage not matching 1.
<         $sectionselect = 'course = :course AND section <> 1';
<         $sitesections = $DB->get_recordset_select('course_sections', $sectionselect, ['course' => SITEID]);
<         $newsection1cmids = [];
<         foreach ($sitesections as $section) {
<             // Check if we have anything to process for this section.
<             if (empty($section->sequence)) {
<                 // If there's none, ignore.
<                 continue;
<             }
<             // Fetch the course module IDs of the course modules in the section.
<             $cmids = explode(',', $section->sequence);
<             $nonglossarycmids = [];
<             // Update the section in the course_modules table for glossary instances if necessary.
<             foreach ($cmids as $cmid) {
<                 $params = [
<                     'id' => $cmid,
<                     'module' => $glossarymoduleid
<                 ];
<                 // Check if the record in the course_modules tables is that of a glossary activity.
<                 if ($DB->record_exists('course_modules', $params)) {
<                     // If so, move it to front page's section 1.
<                     $DB->set_field('course_modules', 'section', $fpsection1, $params);
<                     $newsection1cmids[] = $cmid;
<                 } else {
<                     // Otherwise, ignore this course module as we only want to update glossary items.
<                     $nonglossarycmids[] = $cmid;
<                 }
<             }
<             // Check if we need to update the section record or we can delete it.
<             if (!empty($nonglossarycmids)) {
<                 // Update the section record with a sequence that now excludes the glossary instance(s) (if it changed).
<                 $sequence = implode(',', $nonglossarycmids);
<                 if ($sequence != $section->sequence) {
<                     $DB->set_field('course_sections', 'sequence', $sequence, ['id' => $section->id]);
<                 }
<             } else {
<                 // This section doesn't contain any items anymore, we can remove this.
<                 $DB->delete_records('course_sections', ['id' => $section->id]);
<             }
<         }
<         $sitesections->close();
< 
<         // Update the sequence field for the site's section 1 if necessary.
<         if (!empty($newsection1cmids)) {
<             $section1params = [
<                 'course' => SITEID,
<                 'section' => 1
<             ];
<             $section1sequence = $DB->get_field('course_sections', 'sequence', $section1params);
<             $newsection1sequence = implode(',', array_merge([$section1sequence], $newsection1cmids));
<             // Update the sequence field of the first section for the front page.
<             $DB->set_field('course_sections', 'sequence', $newsection1sequence, $section1params);
<         }
< 
<         upgrade_mod_savepoint(true, 2018051401, 'glossary');
<     }
< 
<     // Automatically generated Moodle v3.6.0 release upgrade line.
<     // Put any upgrade step following this.
< 
<     // Automatically generated Moodle v3.7.0 release upgrade line.



>     // Automatically generated Moodle v3.9.0 release upgrade line.


    // Put any upgrade step following this.


<     // Automatically generated Moodle v3.8.0 release upgrade line.



>     // Automatically generated Moodle v4.0.0 release upgrade line.


    // Put any upgrade step following this.


<     // Automatically generated Moodle v3.9.0 release upgrade line.



>     // Automatically generated Moodle v4.1.0 release upgrade line.


    // Put any upgrade step following this.

    return true;
}