#pragma once

#include <atomic>
#include <memory>
#include <stdint.h>

struct RootSet {

  /// Register the root node for version after adding mutations
  void add(uint32_t node, int64_t version);

  /// Inform that there will be no calls to rootForVersion with a version less
  /// than `oldestVersion`
  void setOldestVersion(int64_t oldestVersion);

  /// Foreign threads may freely interact with a `ThreadSafeHandle`, as long as
  /// the latest version as of obtaining the handle is greater than
  /// `oldestVersion`, and they only read versions >= `oldestVersion` and <= the
  /// version as of obtaining the handle.
  struct ThreadSafeHandle {

    /// Get a root node that can correctly be used for `version`
    uint32_t rootForVersion(int64_t version) const;

    /// @private
    struct Impl;

  private:
    Impl *impl; // not owned
  };

  /// Safe to call from foreign threads
  ThreadSafeHandle getThreadSafeHandle() const;

  const uint32_t *roots() const;
  int rootCount() const;

  RootSet();

  ~RootSet();

  /// @private
  struct Impl;

private:
  Impl *impl;
};