#pragma once

#include <memory>

#include <string>

#include "envoy/extensions/quic/connection_debug_visitor/quic_stats/v3/quic_stats.pb.h"

#include "envoy/registry/registry.h"

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

#include "source/common/quic/envoy_quic_connection_debug_visitor_factory_interface.h"

#include "quiche/quic/core/frames/quic_connection_close_frame.h"

#include "quiche/quic/core/quic_connection.h"

#include "quiche/quic/core/quic_session.h"

#include "quiche/quic/core/quic_types.h"

namespace Envoy {

namespace Extensions {

namespace Quic {

namespace ConnectionDebugVisitors {

namespace QuicStats {

#define ALL_QUIC_STATS(COUNTER, GAUGE, HISTOGRAM)                                                  \

struct QuicStats {

  ALL_QUIC_STATS(GENERATE_COUNTER_STRUCT, GENERATE_GAUGE_STRUCT, GENERATE_HISTOGRAM_STRUCT)

};

class Config;

// Visitor class that publishes various QUICHE connection stats as Envoy stats.

class QuicStatsVisitor : public quic::QuicConnectionDebugVisitor {

public:

  QuicStatsVisitor(Config& config, Event::Dispatcher& dispatcher);

  // quic::QuicConnectionDebugVisitor

  void OnConnectionClosed(const quic::QuicConnectionCloseFrame& frame,

                          quic::ConnectionCloseSource source) override;

  // This is virtual so that tests can override it.

  virtual const quic::QuicConnectionStats& getQuicStats() PURE;

private:

  void recordStats();

  Config& config_;

  Event::TimerPtr timer_;

  quic::QuicPacketCount last_packets_sent_{};

  quic::QuicPacketCount last_packets_retransmitted_{};

  quic::QuicPacketCount last_packets_received_{};

  size_t last_num_amplification_throttling_{};

  size_t last_num_path_degrading_{};

  size_t last_num_forward_progress_after_path_degrading_{};

};

class QuicStatsVisitorProd final : public QuicStatsVisitor {

public:

  QuicStatsVisitorProd(Config& config, Event::Dispatcher& dispatcher, quic::QuicSession& session)

  const quic::QuicConnectionStats& getQuicStats() override;

private:

  quic::QuicSession& session_;

};

class Config : public Envoy::Quic::EnvoyQuicConnectionDebugVisitorFactoryInterface {

public:

  Config(const envoy::extensions::quic::connection_debug_visitor::quic_stats::v3::Config& config,

         Stats::Scope& scope);

  std::unique_ptr<quic::QuicConnectionDebugVisitor>

  createQuicConnectionDebugVisitor(Event::Dispatcher& dispatcher, quic::QuicSession& session,

                                   const StreamInfo::StreamInfo& stream_info) override;

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

  QuicStats stats_;

private:

  static QuicStats generateStats(Stats::Scope& scope);

};

class QuicStatsFactoryFactory

    : public Envoy::Quic::EnvoyQuicConnectionDebugVisitorFactoryFactoryInterface {

public:

  Envoy::Quic::EnvoyQuicConnectionDebugVisitorFactoryInterfacePtr

  createFactory(const Protobuf::Message& config,

                Server::Configuration::ListenerFactoryContext& listener_context) override;

};

DECLARE_FACTORY(QuicStatsFactoryFactory);

} // namespace QuicStats

} // namespace ConnectionDebugVisitors

} // namespace Quic

} // namespace Extensions

} // namespace Envoy