#pragma once

#include "source/common/common/hash.h"

#include "source/server/hot_restarting_base.h"

namespace Envoy {

namespace Server {

class HotRestartMessageSender {

public:

  virtual void sendHotRestartMessage(envoy::HotRestartMessage&& msg) PURE;

};

/**

 * The parent half of hot restarting. Listens for requests and commands from the child.

 * This outer class only handles evented socket I/O. The actual hot restart logic lives in

 * HotRestartingParent::Internal.

 */

class HotRestartingParent : public HotRestartingBase, public HotRestartMessageSender {

public:

  HotRestartingParent(int base_id, int restart_epoch, const std::string& socket_path,

                      mode_t socket_mode);

  void initialize(Event::Dispatcher& dispatcher, Server::Instance& server);

  void shutdown();

  void sendHotRestartMessage(envoy::HotRestartMessage&& msg) override;

  // The hot restarting parent's hot restart logic. Each function is meant to be called to fulfill a

  // request from the child for that action.

  class Internal : public Network::NonDispatchedUdpPacketHandler {

  public:

    explicit Internal(Server::Instance* server, HotRestartMessageSender& udp_sender);

    // Return value is the response to return to the child.

    envoy::HotRestartMessage shutdownAdmin();

    // Return value is the response to return to the child.

    envoy::HotRestartMessage

    getListenSocketsForChild(const envoy::HotRestartMessage::Request& request);

    // 'stats' is a field in the reply protobuf to be sent to the child, which we should populate.

    void exportStatsToChild(envoy::HotRestartMessage::Reply::Stats* stats);

    void recordDynamics(envoy::HotRestartMessage::Reply::Stats* stats, const std::string& name,

                        Stats::StatName stat_name);

    void drainListeners();

    // Network::NonDispatchedUdpPacketHandler

    void handle(uint32_t worker_index, const Network::UdpRecvData& packet) override;

  private:

    Server::Instance* const server_{};

    HotRestartMessageSender& udp_sender_;

  };

private:

  void onSocketEvent();

  const int restart_epoch_;

  sockaddr_un child_address_;

  sockaddr_un child_address_udp_forwarding_;

  Event::FileEventPtr socket_event_;

  OptRef<Event::Dispatcher> dispatcher_;

  std::unique_ptr<Internal> internal_;

};

} // namespace Server

} // namespace Envoy