#pragma once

#include <functional>

#include <string>

#include <vector>

#include "envoy/config/cluster/v3/cluster.pb.h"

#include "envoy/config/cluster/v3/cluster.pb.validate.h"

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

#include "envoy/config/subscription.h"

#include "envoy/protobuf/message_validator.h"

#include "envoy/server/factory_context.h"

#include "envoy/stats/scope.h"

#include "envoy/upstream/cluster_manager.h"

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

#include "source/common/protobuf/protobuf.h"

#include "source/common/upstream/cds_api_helper.h"

namespace Envoy {

namespace Upstream {

#define ALL_CDS_STATS(COUNTER, GAUGE)                                                              \

struct CdsStats {

  ALL_CDS_STATS(GENERATE_COUNTER_STRUCT, GENERATE_GAUGE_STRUCT)

};

/**

 * CDS API implementation that fetches via Subscription.

 * This supports the wildcard subscription to a single source.

 */

class CdsApiImpl : public CdsApi,

                   Envoy::Config::SubscriptionBase<envoy::config::cluster::v3::Cluster> {

public:

  static absl::StatusOr<CdsApiPtr>

  create(const envoy::config::core::v3::ConfigSource& cds_config,

         const xds::core::v3::ResourceLocator* cds_resources_locator, ClusterManager& cm,

         Stats::Scope& scope, ProtobufMessage::ValidationVisitor& validation_visitor,

         Server::Configuration::ServerFactoryContext& factory_context,

         bool support_multi_ads_sources);

  // Upstream::CdsApi

private:

  // Config::SubscriptionCallbacks

  absl::Status onConfigUpdate(const std::vector<Config::DecodedResourceRef>& resources,

                              const std::string& version_info) override;

  absl::Status onConfigUpdate(const std::vector<Config::DecodedResourceRef>& added_resources,

                              const Protobuf::RepeatedPtrField<std::string>& removed_resources,

                              const std::string& system_version_info) override;

  void onConfigUpdateFailed(Envoy::Config::ConfigUpdateFailureReason reason,

                            const EnvoyException* e) override;

  CdsApiImpl(const envoy::config::core::v3::ConfigSource& cds_config,

             const xds::core::v3::ResourceLocator* cds_resources_locator, ClusterManager& cm,

             Stats::Scope& scope, ProtobufMessage::ValidationVisitor& validation_visitor,

             Server::Configuration::ServerFactoryContext& factory_context,

             bool support_multi_ads_sources, absl::Status& creation_status);

  void runInitializeCallbackIfAny();

  CdsApiHelper helper_;

  ClusterManager& cm_;

  Stats::ScopeSharedPtr scope_;

  Server::Configuration::ServerFactoryContext& factory_context_;

  CdsStats stats_;

  // This enables tracking the resources via SotW for wildcard-CDS, so concurrent OD-CDS

  // resources won't get overridden when a CDS-wildcard update arrives.

  // TODO(adisuissa): once proper support for an xDS-Caching layer is added,

  // this will not be relevant, as the callbacks will be similar to delta-xDS

  // from each collection source.

  const bool support_multi_ads_sources_;

  absl::flat_hash_set<std::string> sotw_resource_names_;

  Config::SubscriptionPtr subscription_;

  std::function<void()> initialize_callback_;

};

} // namespace Upstream

} // namespace Envoy