#pragma once

#include "envoy/common/optref.h"

#include "envoy/config/typed_config.h"

namespace Envoy {

namespace Http {

/**

 * Interface for generic header key formatting.

 */

class HeaderKeyFormatter {

public:

  /**

   * Given an input key return the formatted key to encode.

   */

  virtual std::string format(absl::string_view key) const PURE;

};

using HeaderKeyFormatterConstPtr = std::unique_ptr<const HeaderKeyFormatter>;

using HeaderKeyFormatterOptConstRef = OptRef<const HeaderKeyFormatter>;

/**

 * Interface for header key formatters that are stateful. A formatter is created during decoding

 * headers, attached to the header map, and can then be used during encoding for reverse

 * translations if applicable.

 */

class StatefulHeaderKeyFormatter : public HeaderKeyFormatter {

public:

  /**

   * Called for each header key received by the codec.

   */

  virtual void processKey(absl::string_view key) PURE;

  /**

   * Called to save received reason phrase

   */

  virtual void setReasonPhrase(absl::string_view reason_phrase) PURE;

  /**

   * Called to get saved reason phrase

   */

  virtual absl::string_view getReasonPhrase() const PURE;

};

using StatefulHeaderKeyFormatterPtr = std::unique_ptr<StatefulHeaderKeyFormatter>;

using StatefulHeaderKeyFormatterOptRef = OptRef<StatefulHeaderKeyFormatter>;

using StatefulHeaderKeyFormatterOptConstRef = OptRef<const StatefulHeaderKeyFormatter>;

/**

 * Interface for creating stateful header key formatters.

 */

class StatefulHeaderKeyFormatterFactory {

public:

  /**

   * Create a new formatter.

   */

  virtual StatefulHeaderKeyFormatterPtr create() PURE;

};

using StatefulHeaderKeyFormatterFactorySharedPtr =

    std::shared_ptr<StatefulHeaderKeyFormatterFactory>;

/**

 * Extension configuration for stateful header key formatters.

 */

class StatefulHeaderKeyFormatterFactoryConfig : public Config::TypedFactory {

public:

  virtual StatefulHeaderKeyFormatterFactorySharedPtr

  createFromProto(const Protobuf::Message& config) PURE;

};

} // namespace Http

} // namespace Envoy