Prev/Next Post Filtering

add_filter('get_previous_post_join','sql_get_adjacent_post_join');
add_filter('get_next_post_join','sql_get_adjacent_post_join');
add_filter('get_previous_post_sort','sql_get_adjacent_post_sort');
add_filter('get_next_post_sort','sql_get_adjacent_post_sort');
add_filter( 'get_previous_post_where', 'filter_private_future_nextprevious_links' );
add_filter( 'get_next_post_where', 'filter_private_future_nextprevious_links' );

function sql_get_adjacent_post_join($join) {
    global $post, $wpdb;
    if('story-images' == get_post_type() || 'editorials' == get_post_type()) {
        return $join . " INNER JOIN $wpdb->postmeta AS m ON p.ID = m.post_id";
    }
}


function filter_private_future_nextprevious_links($where) {
    global $post;

    //check for selected editorial and get ID to pass into $where
    if('story-images' == get_post_type()) {
        if(get_field('editorial')) {
            foreach(get_field('editorial') as $post_object):
                 $editorial_id = $post_object->ID;
            endforeach;
        }
        return $where . " AND m.meta_key = 'editorial' AND m.meta_value = $editorial_id";
    }

    //check for selected editorial and get ID to pass into $where
    if('editorials' == get_post_type()) {

        if(get_field('author') == 'Randy') {
            $this_id = $post->ID;
            $stories = get_field('stories', 863);
            $story_ids = array();
            foreach($stories as $story) {
                $story_ids[] = $story->ID;
            }
            $ids_for_where = implode(',', $story_ids);
            return $where . " AND m.meta_key = 'author' AND m.meta_value = 'Randy' AND p.ID IN ($ids_for_where)";
        } elseif(get_field('author') == 'Melissa') {
            $this_id = $post->ID;
            $stories = get_field('stories', 881);
            $story_ids = array();
            foreach($stories as $story) {
                $story_ids[] = $story->ID;
            }
            $ids_for_where = implode(',', $story_ids);
            return $where . " AND m.meta_key = 'author' AND m.meta_value = 'Melissa' AND p.ID IN ($ids_for_where)";
        }
    }
}

function sql_get_adjacent_post_sort($sort) {
    global $post, $wpdb;
    $this_id = $post->ID;
    if('story-images' == get_post_type()) {
        if(($editorials = get_field('editorial'))) {
            $editorial = current($editorials);
            $editorial_id = $editorial->ID;

            $editorial_images = get_field('editorial-images', $editorial_id);
            $editorial_image_ids = array();
            foreach($editorial_images as $editorial_image) {
                $editorial_image_ids[] = $editorial_image->ID;
            }

            if(!empty($editorial_image_ids)) {
                $ids_for_sort = implode(',', $editorial_image_ids);
                echo $ids_for_sort;
                $sort = "ORDER BY FIELD(p.ID, {$ids_for_sort})";
            }
        }
    }
    echo $sort;
    return $sort;
}