/**
* Accessor to parent relations.
*
* @param {?AbstractModel|int|string|array} $parents If provided, add them as parents in relation.
* @param {?string} $collection Collection identifier for the relation, defaults to the model's collection name.
*
* @return {array} Existing parents before modification.
*/
protected function parents($collection = null, $parents = null, $replace = false)
{
if ($collection === null) {
$collection = $this->collectionName();
}
$return = Relation::getParents($this->identity(), $collection);
if ($parents) {
if ($replace) {
$this->deleteAncestors($collection);
}
if (!is_array($parents)) {
$parents = array($parents);
}
foreach ($parents as $parent) {
if ($parent instanceof AbstractModel) {
$parent = $parent->identity();
}
Relation::set($parent, $this->identity(), $collection);
}
}
return $return;
}
