public static function optionsAreValid($post_id, array $item_option) {
        global $usces;

        $ioptkeys = $usces->get_itemOptionKey($post_id, true);
        $ioptkeys = is_array($ioptkeys) ? $ioptkeys : [];

        // first, make sure our option array contains options that actually exist for the item
        foreach ((array)$item_option as $key => $val) {
            if (!in_array($key, $ioptkeys, true)) {
                return false;
            }
        }

        // next, make sure selected values actually exist for their respective options and that
        // required options have values
        foreach ($ioptkeys as $key => $value) {
            $optValues = $usces->get_itemOptions(urldecode($value), $post_id);
            $means = (int)$optValues['means'];
            $essential = (int)$optValues['essential'];
            $curval = isset($item_option[$value]) ? $item_option[$value] : null;
            if (0 === $means) { // select
                if ($essential && ('#NONE#' == $curval || $curval === null)) {
                    return false;
                }
            } elseif (1 === $means) { // multiselect
                if ($essential) {
                    $mselect = 0;
                    foreach ((array)$curval as $mvalue) {
                        if (!empty($mvalue) && '#NONE#' != $mvalue) {
                            $mselect++;
                        }
                    }
                    if ($mselect == 0) {
                        return false;
                    }
                }
            } elseif (in_array($means, [3, 4], true)) { // radio & checkbox
                if ($essential) {
                    if (empty($curval)) {
                        return false;
                    }
                }
            } else { // text
                if ($essential && WCUtils::is_blank($curval)) {
                    return false;
                }
            }

            // an empty value here means that the current option is not required, so an
            // existence check for the value on a selection based option isn't necessary
            if (empty($curval)) {
                continue;
            }

            // check whether the selection exists for the current option
            switch ($means) {
                case 0:
                case 3:
                    $possiblevals = array_map(function ($v) {
                        return trim($v);
                    }, explode("\n", $optValues['value']));
                    if (!in_array(urldecode($curval), $possiblevals, true)) {
                        return false;
                    }
                    break;
                case 1:
                case 4:
                    $possiblevals = array_map(function ($v) {
                        return trim($v);
                    }, explode("\n", $optValues['value']));
                    if (defined('WCEX_WIDGET_CART') && $means === 1) {
                        // `wcex_widget_cart` concatenates multi-select values with a comma for serialization
                        $curval = explode(',', urldecode($curval[array_keys($curval)[0]]));
                    }
                    foreach ($curval as $selkey => $selval) {
                        $selval = defined('WCEX_WIDGET_CART') && $means === 1 ? $selval : urldecode($selval);
                        if (!in_array($selval, $possiblevals, true)) {
                            return false;
                        }
                    }
                    break;
            }
        }

        return true;
    }