selected sku by filter, выбрать ID SKU для установки SKU по умолчанию, исходя из умного фильтра.

init.php

<?
/*
 * выбрать ID SKU для установки SKU по умолчанию, исходя из умного фильтра.
 * */
function getOffersSelectedByFilter(&$arResult, &$arParams, $component){
    //https://pai-bx.com/wiki/1c-bitrix/2357-filtered-sku-in-products-list/
    if(!empty($arParams['FILTER_NAME'])){
        global ${$arParams['FILTER_NAME']};
        $FILTER = ${$arParams['FILTER_NAME']};
        if(!empty($FILTER) && !empty($FILTER['OFFERS']) ) {

            foreach ($arResult['ITEMS'] as &$arItem){
                $arFiltredOffers = [];

                foreach ($FILTER['OFFERS'] as $filterKey=>$arFilterValues)
                {
                    $arFiltredOffers[$filterKey] = array();

                    $arFilterKey = explode('_', $filterKey);
                    $filterPropertyId = array_pop($arFilterKey);
                    $filter_condition = substr($filterKey, 0, 1);

                    foreach ($arItem['OFFERS'] as $arOffer){
                        $returnOffer = false;
                        foreach ($arOffer['PROPERTIES'] as $arProperty){
                            if($arProperty['ID']==$filterPropertyId){
                                if($filter_condition=='='){
                                    // work with property type = S and L
                                    foreach ($arFilterValues as $filterValue){
                                        $VALUE = $arProperty['VALUE'];
                                        if(
                                            isset($arProperty['VALUE_ENUM_ID'])
                                            && !empty($arProperty['VALUE_ENUM_ID'])
                                        ){
                                            $VALUE = $arProperty['VALUE_ENUM_ID'];
                                        }

                                        if(is_array($VALUE)){
                                            if(in_array($filterValue,$VALUE)){
                                                $returnOffer = true;
                                            }
                                        }else{
                                            if($filterValue==$VALUE){
                                                $returnOffer = true;
                                            }
                                        }

                                    }
                                }elseif($filter_condition=='>'){ // ><
                                    // TODO check
                                    $MIN = $arFilterValues[0];
                                    $MAX = $arFilterValues[1];
                                    $VALUE = $arProperty['VALUE'];
                                    //TODO multiple VALUE
                                    if($VALUE>$MIN && $VALUE<$MAX){
                                        $returnOffer = true;
                                    }
                                }
                            }
                        }

                        if($returnOffer){
                            $arFiltredOffers[$filterKey][] = $arOffer['ID'];
                        }
                    }


                }

                $arFiltredOffers = array_values($arFiltredOffers);
                $arAvailOffers = call_user_func_array('array_intersect', $arFiltredOffers);

                $arSelectedOffer = false;
                foreach($arItem['OFFERS'] as $arOffer){
                    if(in_array($arOffer['ID'],$arAvailOffers)){
                        $arSelectedOffer = $arOffer;
                        break;
                    }
                }
                if($arSelectedOffer){
                    $arItem['SELECTED_OFFER_BY_FILTER'] = array(
                        "ID"=>$arSelectedOffer['ID'],
                        "CODE"=>$arSelectedOffer['CODE'],
                    );
                    $arResult['SELECTED_OFFER_BY_FILTER'][$arItem['ID']] = $arItem['SELECTED_OFFER_BY_FILTER'];
                }
            }
        }
    }
}