/**
* If HideUnmatchedFilters is on then remove all filters which are not found in the items by their 'AssociatedFilters' relationship.
*
* @param \DataList $filters list of GridListFilter models
* @param array $parameters
* @return \ArrayList
*/
public function constrainGridListFilters(&$filters, &$parameters = [])
{
$out = new \ArrayList();
if ($this()->{self::SingleFieldName}) {
$ids = $filters->column('ID');
if (count($ids)) {
$items = $this()->GridListItems();
// this is where we keep track of GridListFilters which have been found on items where ID is the key
$foundFilters = array_combine($ids, array_fill(0, count($ids), false));
foreach ($foundFilters as $filterID => &$found) {
/** @var \Page|Model $item */
foreach ($items as $item) {
if ($item->hasExtension(HasGridListFilters::class_name())) {
if ($itemFilters = $item->{HasGridListFilters::relationship_name()}()->column('ID')) {
if (in_array($filterID, $itemFilters)) {
$found = true;
break;
}
}
}
}
}
foreach ($filters as $filter) {
if (isset($foundFilters[$filter->ID])) {
$out->push($filter);
}
}
$filters = $out;
}
}
}
