#pragma once

#if defined(__linux__)

#include "envoy/event/timer.h"

#include "envoy/extensions/transport_sockets/tcp_stats/v3/tcp_stats.pb.h"

#include "envoy/network/connection.h"

#include "envoy/network/filter.h"

#include "envoy/stats/scope.h"

#include "envoy/stats/stats_macros.h"

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

#include "source/extensions/transport_sockets/common/passthrough.h"

// Defined in /usr/include/linux/tcp.h.

struct tcp_info;

namespace Envoy {

namespace Extensions {

namespace TransportSockets {

namespace TcpStats {

#define ALL_TCP_STATS(COUNTER, GAUGE, HISTOGRAM)                                                   \

struct TcpStats {

  ALL_TCP_STATS(GENERATE_COUNTER_STRUCT, GENERATE_GAUGE_STRUCT, GENERATE_HISTOGRAM_STRUCT)

};

class Config {

public:

  Config(const envoy::extensions::transport_sockets::tcp_stats::v3::Config& config_proto,

         Stats::Scope& scope);

  TcpStats stats_;

  const absl::optional<std::chrono::milliseconds> update_period_;

private:

  TcpStats generateStats(Stats::Scope& scope);

};

using ConfigConstSharedPtr = std::shared_ptr<const Config>;

class TcpStatsSocket : public TransportSockets::PassthroughSocket,

                       Logger::Loggable<Logger::Id::connection> {

public:

  TcpStatsSocket(ConfigConstSharedPtr config, Network::TransportSocketPtr inner_socket);

  // Network::TransportSocket

  void setTransportSocketCallbacks(Network::TransportSocketCallbacks& callbacks) override;

  void onConnected() override;

  void closeSocket(Network::ConnectionEvent event) override;

private:

  absl::optional<struct tcp_info> querySocketInfo();

  void recordStats();

  const ConfigConstSharedPtr config_;

  Network::TransportSocketCallbacks* callbacks_{};

  Event::TimerPtr timer_;

  uint32_t last_cx_tx_segments_{};

  uint32_t last_cx_rx_segments_{};

  uint32_t last_cx_tx_data_segments_{};

  uint32_t last_cx_rx_data_segments_{};

  uint32_t last_cx_tx_retransmitted_segments_{};

  uint32_t last_cx_rx_bytes_received_{};

  uint32_t last_cx_tx_bytes_sent_{};

  uint32_t last_cx_tx_unsent_bytes_{};

  uint32_t last_cx_tx_unacked_segments_{};

};

} // namespace TcpStats

} // namespace TransportSockets

} // namespace Extensions

} // namespace Envoy

#endif // defined(__linux__)