#pragma once

#include "envoy/config/xds_manager.h"

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

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

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

namespace Envoy {

namespace Config {

class XdsManagerImpl : public XdsManager {

public:

  XdsManagerImpl(Event::Dispatcher& main_thread_dispatcher, Api::Api& api, Stats::Store& stats,

                 const LocalInfo::LocalInfo& local_info,

                 ProtobufMessage::ValidationContext& validation_context, Server::Instance& server)

  // Config::XdsManager

  absl::Status initialize(const envoy::config::bootstrap::v3::Bootstrap& bootstrap,

                          Upstream::ClusterManager* cm) override;

  absl::Status

  initializeAdsConnections(const envoy::config::bootstrap::v3::Bootstrap& bootstrap) override;

  void startXdstpAdsMuxes() override;

  absl::StatusOr<SubscriptionPtr> subscribeToSingletonResource(

      absl::string_view resource_name, OptRef<const envoy::config::core::v3::ConfigSource> config,

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

      OpaqueResourceDecoderSharedPtr resource_decoder, const SubscriptionOptions& options) override;

  ScopedResume pause(const std::vector<std::string>& type_urls) override;

  absl::Status

  setAdsConfigSource(const envoy::config::core::v3::ApiConfigSource& config_source) override;

private:

  class AuthorityData {

  public:

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

                  absl::flat_hash_set<std::string>&& authority_names, GrpcMuxSharedPtr&& grpc_mux)

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

    // The set of authority names this config-source supports.

    // Note that only the `default_config_source` may have an empty list of authority names.

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

    // The ADS gRPC mux to the server.

    Config::GrpcMuxSharedPtr grpc_mux_;

  };

  // Creates an authority based on a given config source.

  // Returns the new authority, or an error if one occurred.

  absl::StatusOr<AuthorityData>

  createAuthority(const envoy::config::core::v3::ConfigSource& config_source,

                  bool allow_no_authority_names);

  // Validates (syntactically) the config_source by doing the PGV validation.

  absl::Status validateAdsConfig(const envoy::config::core::v3::ApiConfigSource& config_source);

  /**

   * Replaces the current ADS mux with a new one based on the given config.

   * Assumes that the given ads_config is syntactically valid (according to the PGV constraints).

   * @param ads_config an ADS config source to use.

   * @return the status of the operation.

   */

  absl::Status replaceAdsMux(const envoy::config::core::v3::ApiConfigSource& ads_config);

  Server::Instance& server_;

  Event::Dispatcher& main_thread_dispatcher_;

  Api::Api& api_;

  Random::RandomGenerator& random_;

  Stats::Store& stats_;

  const LocalInfo::LocalInfo& local_info_;

  ProtobufMessage::ValidationContext& validation_context_;

  XdsResourcesDelegatePtr xds_resources_delegate_;

  XdsConfigTrackerPtr xds_config_tracker_;

  std::unique_ptr<SubscriptionFactoryImpl> subscription_factory_;

  // The cm_ will only be valid after the cluster-manager is initialized.

  // Note that this implies that the xDS-manager must be shut down properly

  // prior to the cluster-manager deletion.

  Upstream::ClusterManager* cm_;

  GrpcMuxSharedPtr ads_mux_;

  // Stores all authorities as configured in the bootstrap under config_sources.

  // It does not include the default config-source.

  std::vector<AuthorityData> authorities_;

  // The default authority that will be used for cases where the authority in a resource doesn't

  // exist, or doesn't match. This will only be populated if default_config_source

  // is defined in the bootstrap.

  std::unique_ptr<AuthorityData> default_authority_;

};

} // namespace Config

} // namespace Envoy