#pragma once

#include <memory>

#include "envoy/common/time.h"

#include "envoy/rds/config.h"

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

#include "absl/types/optional.h"

namespace Envoy {

namespace Rds {

/**

 * A provider for constant route configurations.

 */

class RouteConfigProvider {

public:

  struct ConfigInfo {

    // A reference to the currently loaded route configuration. Do not hold this reference beyond

    // the caller of configInfo()'s scope.

    const Protobuf::Message& config_;

    // The discovery version that supplied this route. This will be set to "" in the case of

    // static clusters.

    const std::string version_;

  };

  /**

   * @return ConfigConstSharedPtr a route configuration for use during a single request. The

   * returned config may be different on a subsequent call, so a new config should be acquired for

   * each request flow.

   */

  virtual ConfigConstSharedPtr config() const PURE;

  /**

   * @return the configuration information for the currently loaded route configuration. Note that

   * if the provider has not yet performed an initial configuration load, no information will be

   * returned.

   */

  virtual const absl::optional<ConfigInfo>& configInfo() const PURE;

  /**

   * @return the last time this RouteConfigProvider was updated. Used for config dumps.

   */

  virtual SystemTime lastUpdated() const PURE;

  /**

   * Callback used to notify RouteConfigProvider about configuration changes.

   * @return Status indicating if the call was successful or had graceful error handling.

   */

  virtual absl::Status onConfigUpdate() PURE;

};

using RouteConfigProviderPtr = std::unique_ptr<RouteConfigProvider>;

using RouteConfigProviderSharedPtr = std::shared_ptr<RouteConfigProvider>;

} // namespace Rds

} // namespace Envoy