#pragma once

#include <memory>

#include <string>

#include "envoy/common/pure.h"

#include "envoy/config/typed_config.h"

#include "envoy/http/header_map.h"

#include "envoy/server/factory_context.h"

#include "envoy/stream_info/stream_info.h"

namespace Envoy {

namespace Http {

/**

 * Interface class for early header mutation extensions.

 */

class EarlyHeaderMutation {

public:

  /**

   * Mutate the request headers before routing, tracing or any filter processing.

   *

   * @param headers request headers to be mutated.

   * @param stream_info stream info.

   * @return true if the mutation is could be continued for the flollowing extensions.

   * Make no sense if there is no following extensions.

   */

  virtual bool mutate(RequestHeaderMap& headers,

                      const StreamInfo::StreamInfo& stream_info) const PURE;

};

using EarlyHeaderMutationPtr = std::unique_ptr<EarlyHeaderMutation>;

/*

 * A factory for creating early header mutation extensions.

 */

class EarlyHeaderMutationFactory : public Envoy::Config::TypedFactory {

public:

  /**

   * Creates a particular extension implementation.

   *

   * @param config supplies the configuration for the early mutation extension.

   * @return EarlyHeaderMutationPtr the extension instance.

   */

  virtual EarlyHeaderMutationPtr

  createExtension(const Protobuf::Message& config,

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

};

using EarlyHeaderMutationFactoryPtr = std::unique_ptr<EarlyHeaderMutationFactory>;

} // namespace Http

} // namespace Envoy