#pragma once

#include <functional>

#include <list>

#include "envoy/http/filter.h"

#include "envoy/server/admin.h"

#include "source/common/buffer/buffer_impl.h"

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

#include "source/common/http/codes.h"

#include "source/common/http/header_map_impl.h"

#include "source/extensions/filters/http/common/pass_through_filter.h"

#include "absl/strings/string_view.h"

namespace Envoy {

namespace Server {

/**

 * A terminal HTTP filter that implements server admin functionality.

 */

class AdminFilter : public Http::PassThroughFilter,

                    public AdminStream,

                    Logger::Loggable<Logger::Id::admin> {

public:

  using AdminServerCallbackFunction = std::function<Http::Code(

      absl::string_view path_and_query, Http::ResponseHeaderMap& response_headers,

      Buffer::OwnedImpl& response, AdminFilter& filter)>;

  /**

   * Instantiates an AdminFilter.

   *

   * @param admin the admin context from which to create the filter. This is used

   *        to create a request object based on the path.

   */

  AdminFilter(const Admin& admin);

  // Http::StreamFilterBase

  // Handlers relying on the reference should use addOnDestroyCallback()

  // to add a callback that will notify them when the reference is no

  // longer valid.

  void onDestroy() override;

  // Http::StreamDecoderFilter

  Http::FilterHeadersStatus decodeHeaders(Http::RequestHeaderMap& headers,

                                          bool end_stream) override;

  Http::FilterDataStatus decodeData(Buffer::Instance& data, bool end_stream) override;

  Http::FilterTrailersStatus decodeTrailers(Http::RequestTrailerMap& trailers) override;

  // AdminStream

  void addOnDestroyCallback(std::function<void()> cb) override;

  Http::StreamDecoderFilterCallbacks& getDecoderFilterCallbacks() const override;

  const Buffer::Instance* getRequestBody() const override;

  const Http::RequestHeaderMap& getRequestHeaders() const override;

  Http::Utility::QueryParamsMulti queryParams() const override;

private:

  /**

   * Called when an admin request has been completely received.

   */

  void onComplete();

  const Admin& admin_;

  Http::RequestHeaderMap* request_headers_{};

  std::list<std::function<void()>> on_destroy_callbacks_;

  bool end_stream_on_complete_ = true;

};

} // namespace Server

} // namespace Envoy