+<?php namespace BookStack\Entities\Tools;
+
+use BookStack\Entities\EntityProvider;
+use BookStack\Entities\Models\Book;
+use BookStack\Entities\Models\Bookshelf;
+use Illuminate\Support\Collection;
+
+class SiblingFetcher
+{
+
+ /**
+ * Search among the siblings of the entity of given type and id.
+ */
+ public function fetch(string $entityType, int $entityId): Collection
+ {
+ $entity = (new EntityProvider)->get($entityType)->visible()->findOrFail($entityId);
+ $entities = [];
+
+ // Page in chapter
+ if ($entity->isA('page') && $entity->chapter) {
+ $entities = $entity->chapter->getVisiblePages();
+ }
+
+ // Page in book or chapter
+ if (($entity->isA('page') && !$entity->chapter) || $entity->isA('chapter')) {
+ $entities = $entity->book->getDirectChildren();
+ }
+
+ // Book
+ // Gets just the books in a shelf if shelf is in context
+ if ($entity->isA('book')) {
+ $contextShelf = (new ShelfContext)->getContextualShelfForBook($entity);
+ if ($contextShelf) {
+ $entities = $contextShelf->visibleBooks()->get();
+ } else {
+ $entities = Book::visible()->get();
+ }
+ }
+
+ // Shelve
+ if ($entity->isA('bookshelf')) {
+ $entities = Bookshelf::visible()->get();
+ }
+
+ return $entities;
+ }
+}