/**
* Adds a tag instance
*
* @param string $component
* @param string $itemtype
* @param string $itemid
* @param context $context
* @param int $ordering
* @param int $tiuserid tag instance user id, only needed for tag areas with user tagging (such as core/course)
* @return int id of tag_instance
*/
protected function add_instance($component, $itemtype, $itemid, context $context, $ordering, $tiuserid = 0)
{
global $DB;
$this->ensure_fields_exist(array('name', 'rawname'), 'add_instance');
$taginstance = new StdClass();
$taginstance->tagid = $this->id;
$taginstance->component = $component ? $component : '';
$taginstance->itemid = $itemid;
$taginstance->itemtype = $itemtype;
$taginstance->contextid = $context->id;
$taginstance->ordering = $ordering;
$taginstance->timecreated = time();
$taginstance->timemodified = $taginstance->timecreated;
$taginstance->tiuserid = $tiuserid;
$taginstance->id = $DB->insert_record('tag_instance', $taginstance);
// Trigger tag added event.
\core\event\tag_added::create_from_tag_instance($taginstance, $this->name, $this->rawname, true)->trigger();
return $taginstance->id;
}
/**
* Combines several other tags into this one
*
* Combining rules:
* - current tag becomes the "main" one, all instances
* pointing to other tags are changed to point to it.
* - if any of the tags is standard, the "main" tag becomes standard too
* - all tags except for the current ("main") are deleted, even when they are standard
*
* @param core_tag_tag[] $tags tags to combine into this one
*/
public function combine_tags($tags)
{
global $DB;
$this->ensure_fields_exist(array('id', 'tagcollid', 'isstandard', 'name', 'rawname'), 'combine_tags');
// Retrieve all tag objects, find if there are any standard tags in the set.
$isstandard = false;
$tagstocombine = array();
$ids = array();
$relatedtags = $this->get_manual_related_tags();
foreach ($tags as $tag) {
$tag->ensure_fields_exist(array('id', 'tagcollid', 'isstandard', 'tagcollid', 'name', 'rawname'), 'combine_tags');
if ($tag && $tag->id != $this->id && $tag->tagcollid == $this->tagcollid) {
$isstandard = $isstandard || $tag->isstandard;
$tagstocombine[$tag->name] = $tag;
$ids[] = $tag->id;
$relatedtags = array_merge($relatedtags, $tag->get_manual_related_tags());
}
}
if (empty($tagstocombine)) {
// Nothing to do.
return;
}
// Combine all manually set related tags, exclude itself all the tags it is about to be combined with.
if ($relatedtags) {
$relatedtags = array_map(function ($t) {
return $t->name;
}, $relatedtags);
array_unique($relatedtags);
$relatedtags = array_diff($relatedtags, [$this->name], array_keys($tagstocombine));
}
$this->set_related_tags($relatedtags);
// Combine all correlated tags, exclude itself all the tags it is about to be combined with.
$this->combine_correlated_tags($tagstocombine);
// If any of the duplicate tags are standard, mark this one as standard too.
if ($isstandard && !$this->isstandard) {
$this->update(array('isstandard' => 1));
}
// Go through all instances of each tag that needs to be combined and make them point to this tag instead.
// We go though the list one by one because otherwise looking-for-duplicates logic would be too complicated.
foreach ($tagstocombine as $tag) {
$params = array('tagid' => $tag->id, 'mainid' => $this->id);
$mainsql = 'SELECT ti.*, t.name, t.rawname, tim.id AS alreadyhasmaintag ' . 'FROM {tag_instance} ti ' . 'LEFT JOIN {tag} t ON t.id = ti.tagid ' . 'LEFT JOIN {tag_instance} tim ON ti.component = tim.component AND ' . ' ti.itemtype = tim.itemtype AND ti.itemid = tim.itemid AND ' . ' ti.tiuserid = tim.tiuserid AND tim.tagid = :mainid ' . 'WHERE ti.tagid = :tagid';
$records = $DB->get_records_sql($mainsql, $params);
foreach ($records as $record) {
if ($record->alreadyhasmaintag) {
// Item is tagged with both main tag and the duplicate tag.
// Remove instance pointing to the duplicate tag.
$tag->delete_instance_as_record($record, false);
$sql = "UPDATE {tag_instance} SET ordering = ordering - 1\n WHERE itemtype = :itemtype\n AND itemid = :itemid AND component = :component AND tiuserid = :tiuserid\n AND ordering > :ordering";
$DB->execute($sql, (array) $record);
} else {
// Item is tagged only with duplicate tag but not the main tag.
// Replace tagid in the instance pointing to the duplicate tag with this tag.
$DB->update_record('tag_instance', array('id' => $record->id, 'tagid' => $this->id));
\core\event\tag_removed::create_from_tag_instance($record, $record->name, $record->rawname)->trigger();
$record->tagid = $this->id;
\core\event\tag_added::create_from_tag_instance($record, $this->name, $this->rawname)->trigger();
}
}
}
// Finally delete all tags that we combined into the current one.
self::delete_tags($ids);
}
