#pragma once

#include "envoy/config/typed_config.h"

#include "envoy/network/address.h"

#include "envoy/protobuf/message_validator.h"

#include "envoy/server/factory_context.h"

#include "quiche/quic/platform/api/quic_socket_address.h"

namespace Envoy {

namespace Quic {

// An interface to provide the server's preferred addresses at runtime.

class EnvoyQuicServerPreferredAddressConfig {

public:

  // The set of addresses used to configure the server preferred addresses.

  struct Addresses {

    // Addresses that client is requested to use.

    quic::QuicSocketAddress ipv4_;

    quic::QuicSocketAddress ipv6_;

    // If destination NAT is applied between the client and Envoy, the addresses that

    // Envoy will see for client traffic to the server preferred address. If this is not

    // set, Envoy will expect to receive server preferred address traffic on the above addresses.

    //

    // A DNAT address will be ignored if the corresponding SPA address is not set.

    quic::QuicSocketAddress dnat_ipv4_;

    quic::QuicSocketAddress dnat_ipv6_;

  };

  /**

   * Called during config loading.

   * @param local_address the configured default listening address.

   * Returns a pair of the server preferred addresses in form of {IPv4, IPv6} which will be used for

   * the entire life time of the QUIC listener. An uninitialized address value means no preferred

   * address for that address family.

   */

  virtual Addresses

  getServerPreferredAddresses(const Network::Address::InstanceConstSharedPtr& local_address) PURE;

};

using EnvoyQuicServerPreferredAddressConfigPtr =

    std::unique_ptr<EnvoyQuicServerPreferredAddressConfig>;

class EnvoyQuicServerPreferredAddressConfigFactory : public Config::TypedFactory {

public:

  /**

   * Returns an EnvoyQuicServerPreferredAddressConfig object according to the given server preferred

   * address config.

   */

  virtual EnvoyQuicServerPreferredAddressConfigPtr

  createServerPreferredAddressConfig(const Protobuf::Message& config,

                                     ProtobufMessage::ValidationVisitor& validation_visitor,

                                     Server::Configuration::ServerFactoryContext& context) PURE;

};

} // namespace Quic

} // namespace Envoy