// #pragma once
//
// #include <memory>
//
// #include "data_structures/concurrent/concurrent_map.hpp"
// #include "storage/indexes/index_record.hpp"
// #include "storage/indexes/index_record_collection.hpp"
// #include "storage/label/label.hpp"
//
// template <class Key, class Item>
// class Index
// {
//   public:
//   using container_t = ConcurrentMap<Key, Item>;
//
//   Index() : index(std::make_unique<container_t>()) {}
//
//   auto update(const Label &label, VertexIndexRecord &&index_record)
//   {
//     auto accessor = index->access();
//     auto label_ref = label_ref_t(label);
//
//     // create Index Record Collection if it doesn't exist
//     if (!accessor.contains(label_ref)) {
//       accessor.insert(label_ref, std::move(VertexIndexRecordCollection()));
//     }
//
//     // add Vertex Index Record to the Record Collection
//     auto &record_collection = (*accessor.find(label_ref)).second;
//     record_collection.add(std::forward<VertexIndexRecord>(index_record));
//   }
//
//   VertexIndexRecordCollection &find(const Label &label)
//   {
//     // TODO: accessor should be outside?
//     // bacause otherwise GC could delete record that has just be returned
//     auto label_ref = label_ref_t(label);
//     auto accessor = index->access();
//     return (*accessor.find(label_ref)).second;
//   }
//
//   private:
//   std::unique_ptr<container_t> index;
// };