#pragma once

#include "envoy/config/core/v3/http_service.pb.h"

#include "envoy/upstream/cluster_manager.h"

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

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

#include "source/extensions/stat_sinks/open_telemetry/open_telemetry_impl.h"

namespace Envoy {

namespace Extensions {

namespace StatSinks {

namespace OpenTelemetry {

/**

 * HTTP implementation of OtlpMetricsExporter.

 * Exports OTLP metrics over HTTP following the OTLP/HTTP specification.

 */

class OpenTelemetryHttpMetricsExporter : public OtlpMetricsExporter,

                                         public Http::AsyncClient::Callbacks,

                                         public Logger::Loggable<Logger::Id::stats> {

public:

  OpenTelemetryHttpMetricsExporter(Upstream::ClusterManager& cluster_manager,

                                   const envoy::config::core::v3::HttpService& http_service);

  // OtlpMetricsExporter

  void send(MetricsExportRequestPtr&& metrics) override;

  // Http::AsyncClient::Callbacks

  void onSuccess(const Http::AsyncClient::Request&, Http::ResponseMessagePtr&&) override;

  void onFailure(const Http::AsyncClient::Request&, Http::AsyncClient::FailureReason) override;

private:

  Upstream::ClusterManager& cluster_manager_;

  envoy::config::core::v3::HttpService http_service_;

  // Track active HTTP requests to cancel them on destruction.

  Http::AsyncClientRequestTracker active_requests_;

  std::vector<std::pair<const Http::LowerCaseString, const std::string>> parsed_headers_to_add_;

};

} // namespace OpenTelemetry

} // namespace StatSinks

} // namespace Extensions

} // namespace Envoy