#pragma once

#include <cstdint>

#include <queue>

#include <string>

#include <vector>

#include "envoy/http/codec.h"

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

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

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

#include "quiche/http2/adapter/data_source.h"

#include "quiche/http2/hpack/hpack_encoder.h"

namespace Envoy {

namespace Http {

namespace Http2 {

/**

 * A class that creates and sends METADATA payloads. A METADATA payload is a

 * group of string key value pairs encoded in HTTP/2 header blocks. METADATA

 * frames are constructed in two steps: first, the stream submits the

 * MetadataMapVector to the encoder, and later, the MetadataSources generate

 * frame payloads for transmission on the wire.

 */

class NewMetadataEncoder : Logger::Loggable<Logger::Id::http2> {

public:

  using MetadataSourceVector = std::vector<std::unique_ptr<http2::adapter::MetadataSource>>;

  NewMetadataEncoder();

  /**

   * Creates wire format HTTP/2 header block from a vector of metadata maps.

   * @param metadata_map_vector supplies the metadata map vector to encode.

   * @return whether encoding is successful.

   */

  MetadataSourceVector createSources(const MetadataMapVector& metadata_map_vector);

private:

  std::unique_ptr<http2::adapter::MetadataSource> createSource(const MetadataMap& metadata_map);

  spdy::HpackEncoder deflater_;

};

} // namespace Http2

} // namespace Http

} // namespace Envoy