#pragma once

#include "envoy/common/random_generator.h"

#include "envoy/config/subscription.h"

#include "envoy/event/dispatcher.h"

#include "envoy/service/discovery/v3/discovery.pb.h"

#include "source/common/config/api_version.h"

#include "source/common/config/type_to_endpoint.h"

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

#include "source/extensions/config_subscription/rest/rest_api_fetcher.h"

namespace Envoy {

namespace Config {

/**

 * REST implementation of the API Subscription interface. This fetches the API via periodic polling

 * with jitter (based on RestApiFetcher). The REST requests are POSTs of the JSON canonical

 * representation of the DiscoveryRequest proto and the responses are in the form of the JSON

 * canonical representation of DiscoveryResponse. This implementation is responsible for translating

 * between the proto serializable objects in the Subscription API and the REST JSON representation.

 */

class HttpSubscriptionImpl : public Http::RestApiFetcher,

                             public Config::Subscription,

                             Logger::Loggable<Logger::Id::config> {

public:

  HttpSubscriptionImpl(const LocalInfo::LocalInfo& local_info, Upstream::ClusterManager& cm,

                       const std::string& remote_cluster_name, Event::Dispatcher& dispatcher,

                       Random::RandomGenerator& random, std::chrono::milliseconds refresh_interval,

                       std::chrono::milliseconds request_timeout,

                       const Protobuf::MethodDescriptor& service_method, absl::string_view type_url,

                       SubscriptionCallbacks& callbacks,

                       OpaqueResourceDecoderSharedPtr resource_decoder, SubscriptionStats stats,

                       std::chrono::milliseconds init_fetch_timeout,

                       ProtobufMessage::ValidationVisitor& validation_visitor);

  // Config::Subscription

  void start(const absl::flat_hash_set<std::string>& resource_names) override;

  void

  updateResourceInterest(const absl::flat_hash_set<std::string>& update_to_these_names) override;

  // Http::RestApiFetcher

  void createRequest(Http::RequestMessage& request) override;

  void parseResponse(const Http::ResponseMessage& response) override;

  void onFetchComplete() override;

  void onFetchFailure(Config::ConfigUpdateFailureReason reason, const EnvoyException* e) override;

private:

  void handleFailure(Config::ConfigUpdateFailureReason reason, const EnvoyException* e);

  void disableInitFetchTimeoutTimer();

  std::string path_;

  Protobuf::RepeatedPtrField<std::string> resources_;

  envoy::service::discovery::v3::DiscoveryRequest request_;

  Config::SubscriptionCallbacks& callbacks_;

  Config::OpaqueResourceDecoderSharedPtr resource_decoder_;

  SubscriptionStats stats_;

  Event::Dispatcher& dispatcher_;

  std::chrono::milliseconds init_fetch_timeout_;

  Event::TimerPtr init_fetch_timeout_timer_;

  ProtobufMessage::ValidationVisitor& validation_visitor_;

};

class HttpSubscriptionFactory : public ConfigSubscriptionFactory {

public:

  /**

   * Extract refresh_delay as a std::chrono::milliseconds from

   * envoy::config::core::v3::ApiConfigSource.

   */

  static std::chrono::milliseconds

  apiConfigSourceRefreshDelay(const envoy::config::core::v3::ApiConfigSource& api_config_source);

  /**

   * Extract request_timeout as a std::chrono::milliseconds from

   * envoy::config::core::v3::ApiConfigSource. If request_timeout isn't set in the config source, a

   * default value of 1s will be returned.

   */

  static std::chrono::milliseconds

  apiConfigSourceRequestTimeout(const envoy::config::core::v3::ApiConfigSource& api_config_source);

};

} // namespace Config

} // namespace Envoy