#pragma once

#include <regex>

#include "envoy/admin/v3/server_info.pb.h"

#include "envoy/init/manager.h"

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

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

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

namespace Envoy {

namespace Server {

namespace Utility {

// HistogramBucketsMode determines how histogram statistics get reported. Not

// all modes are supported for all formats, with the "Unset" variant allowing

// different formats to have different default behavior.

enum class HistogramBucketsMode {

  Unset,

  Summary,

  Cumulative,

  Disjoint,

  Detailed,

  PrometheusNative

};

void populateFallbackResponseHeaders(Http::Code code, Http::ResponseHeaderMap& header_map);

absl::Status histogramBucketsParam(const Http::Utility::QueryParamsMulti& params,

                                   HistogramBucketsMode& histogram_buckets_mode);

absl::optional<std::string> formatParam(const Http::Utility::QueryParamsMulti& params);

absl::optional<std::string> nonEmptyQueryParam(const Http::Utility::QueryParamsMulti& params,

                                               const std::string& key);

} // namespace Utility

} // namespace Server

} // namespace Envoy