#pragma once

#include <memory>

#include "envoy/common/pure.h"

#include "envoy/common/time.h"

#include "envoy/config/route/v3/route.pb.h"

#include "envoy/rds/route_config_update_receiver.h"

#include "envoy/service/discovery/v3/discovery.pb.h"

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

#include "absl/types/optional.h"

namespace Envoy {

namespace Router {

/**

 * A primitive that keeps track of updates to a RouteConfiguration.

 */

class RouteConfigUpdateReceiver : public Rds::RouteConfigUpdateReceiver {

public:

  /**

   * Same purpose as Rds::RouteConfigUpdateReceiver::protobufConfiguration()

   * but the return is downcasted to proper type.

   * @return current RouteConfiguration downcasted from Protobuf::Message&

   */

  virtual const envoy::config::route::v3::RouteConfiguration&

  protobufConfigurationCast() const PURE;

  using VirtualHostRefVector =

      std::vector<std::reference_wrapper<const envoy::config::route::v3::VirtualHost>>;

  /**

   * Called on updates via VHDS.

   * @param added_vhosts supplies VirtualHosts that have been added.

   * @param added_resource_ids set of resources IDs (names + aliases) added.

   * @param removed_resources supplies names of VirtualHosts that have been removed.

   * @param version_info supplies RouteConfiguration version.

   * @return bool whether RouteConfiguration has been updated.

   */

  virtual bool onVhdsUpdate(const VirtualHostRefVector& added_vhosts,

                            std::set<std::string>&& added_resource_ids,

                            const Protobuf::RepeatedPtrField<std::string>& removed_resources,

                            const std::string& version_info) PURE;

  /**

   * @return bool return whether VHDS configuration has been changed in the last RDS update.

   */

  // TODO(dmitri-d): Consider splitting RouteConfigUpdateReceiver into a RouteConfig state and a

  // last update state. The latter could be passed to callbacks as a parameter, which would make the

  // intent and the lifecycle of the "last update state" less muddled.

  virtual bool vhdsConfigurationChanged() const PURE;

  /**

   * @return the union of all resource names and aliases (if any) received with the last VHDS

   * update.

   */

  virtual const std::set<std::string>& resourceIdsInLastVhdsUpdate() PURE;

};

using RouteConfigUpdatePtr = std::unique_ptr<RouteConfigUpdateReceiver>;

} // namespace Router

} // namespace Envoy