#pragma once

#include "envoy/api/api.h"

#include "envoy/common/backoff_strategy.h"

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

#include "envoy/config/custom_config_validators.h"

#include "envoy/config/grpc_mux.h"

#include "envoy/config/subscription.h"

#include "envoy/config/typed_config.h"

#include "envoy/local_info/local_info.h"

#include "envoy/protobuf/message_validator.h"

#include "envoy/stats/scope.h"

#include "envoy/upstream/load_stats_reporter.h"

#include "xds/core/v3/resource_locator.pb.h"

namespace Envoy {

namespace Server {

class Instance;

} // namespace Server

namespace Grpc {

class RawAsyncClient;

} // namespace Grpc

namespace Config {

class XdsResourcesDelegate;

class XdsConfigTracker;

class SubscriptionFactory {

public:

  static constexpr uint32_t RetryInitialDelayMs = 500;

  static constexpr uint32_t RetryMaxDelayMs = 30000; // Do not cross more than 30s

  /**

   * @return true if a config source comes from the local filesystem.

   */

  static bool

  /**

   * Subscription factory interface.

   *

   * @param config envoy::config::core::v3::ConfigSource to construct from.

   * @param type_url type URL for the resource being subscribed to.

   * @param scope stats scope for any stats tracked by the subscription.

   * @param callbacks the callbacks needed by all Subscription objects, to deliver config updates.

   *                  The callbacks must not result in the deletion of the Subscription object.

   * @param resource_decoder how incoming opaque resource objects are to be decoded.

   * @param options subscription options.

   *

   * @return SubscriptionPtr subscription object corresponding for config and type_url or error

   * status.

   */

  virtual absl::StatusOr<SubscriptionPtr> subscriptionFromConfigSource(

      const envoy::config::core::v3::ConfigSource& config, absl::string_view type_url,

      Stats::Scope& scope, SubscriptionCallbacks& callbacks,

      OpaqueResourceDecoderSharedPtr resource_decoder, const SubscriptionOptions& options) PURE;

  /**

   * Subscription factory for a given ADS grpc-mux.

   *

   * @param ads_grpc_mux the ADS GrpcMux this subscription should use.

   * @param config envoy::config::core::v3::ConfigSource to construct from.

   * @param type_url type URL for the resource being subscribed to.

   * @param scope stats scope for any stats tracked by the subscription.

   * @param callbacks the callbacks needed by all Subscription objects, to deliver config updates.

   *                  The callbacks must not result in the deletion of the Subscription object.

   * @param resource_decoder how incoming opaque resource objects are to be decoded.

   * @param options subscription options.

   *

   * @return SubscriptionPtr subscription object corresponding for config and type_url or error

   * status.

   */

  virtual absl::StatusOr<SubscriptionPtr> subscriptionOverAdsGrpcMux(

      GrpcMuxSharedPtr& ads_grpc_mux, const envoy::config::core::v3::ConfigSource& config,

      absl::string_view type_url, Stats::Scope& scope, SubscriptionCallbacks& callbacks,

      OpaqueResourceDecoderSharedPtr resource_decoder, const SubscriptionOptions& options) PURE;

  /**

   * Collection subscription factory interface for xDS-TP URLs.

   *

   * @param collection_locator collection resource locator.

   * @param config envoy::config::core::v3::ConfigSource for authority resolution.

   * @param type_url type URL for the resources inside the collection.

   * @param scope stats scope for any stats tracked by the subscription.

   * @param callbacks the callbacks needed by all [Collection]Subscription objects, to deliver

   *                  config updates. The callbacks must not result in the deletion of the

   *                  CollectionSubscription object.

   * @param resource_decoder how incoming opaque resource objects are to be decoded.

   *

   * @return SubscriptionPtr subscription object corresponding for collection_locator or error

   * status.

   */

  virtual absl::StatusOr<SubscriptionPtr>

  collectionSubscriptionFromUrl(const xds::core::v3::ResourceLocator& collection_locator,

                                const envoy::config::core::v3::ConfigSource& config,

                                absl::string_view type_url, Stats::Scope& scope,

                                SubscriptionCallbacks& callbacks,

                                OpaqueResourceDecoderSharedPtr resource_decoder) PURE;

};

// A factory class that individual config subscriptions can subclass to be factory-created.

class ConfigSubscriptionFactory : public Config::UntypedFactory {

public:

  struct SubscriptionData {

    const LocalInfo::LocalInfo& local_info_;

    Event::Dispatcher& dispatcher_;

    Upstream::ClusterManager& cm_;

    ProtobufMessage::ValidationVisitor& validation_visitor_;

    Api::Api& api_;

    const Server::Instance& server_;

    OptRef<XdsResourcesDelegate> xds_resources_delegate_;

    OptRef<XdsConfigTracker> xds_config_tracker_;

    const envoy::config::core::v3::ConfigSource& config_;

    absl::string_view type_url_;

    Stats::Scope& scope_;

    SubscriptionCallbacks& callbacks_;

    OpaqueResourceDecoderSharedPtr resource_decoder_;

    const SubscriptionOptions& options_;

    OptRef<const xds::core::v3::ResourceLocator> collection_locator_;

    SubscriptionStats stats_;

    // An optional ADS gRPC mux to be used. Must be provided if ADS

    // is used.

    GrpcMuxSharedPtr ads_grpc_mux_;

  };

  virtual SubscriptionPtr create(SubscriptionData& data) PURE;

};

class MuxFactory : public Config::UntypedFactory {

public:

  virtual void shutdownAll() PURE;

  virtual std::shared_ptr<GrpcMux>

  create(std::shared_ptr<Grpc::RawAsyncClient>&& async_client,

         std::shared_ptr<Grpc::RawAsyncClient>&& async_failover_client,

         Event::Dispatcher& dispatcher, Random::RandomGenerator& random, Stats::Scope& scope,

         const envoy::config::core::v3::ApiConfigSource& ads_config,

         const LocalInfo::LocalInfo& local_info,

         std::unique_ptr<CustomConfigValidators>&& config_validators,

         BackOffStrategyPtr&& backoff_strategy, OptRef<XdsConfigTracker> xds_config_tracker,

         OptRef<XdsResourcesDelegate> xds_resources_delegate,

         std::function<std::unique_ptr<Upstream::LoadStatsReporter>()> load_stats_reporter_factory)

      PURE;

};

} // namespace Config

} // namespace Envoy