#pragma once

#include "envoy/api/api.h"
#include "envoy/config/subscription.h"
#include "envoy/event/dispatcher.h"
#include "envoy/filesystem/filesystem.h"
#include "envoy/protobuf/message_validator.h"

#include "common/common/logger.h"

namespace Envoy {
namespace Config {

/**
 * Filesystem inotify implementation of the API Subscription interface. This allows the API to be
 * consumed on filesystem changes to files containing the JSON canonical representation of
 * lists of xDS resources.
 */
class FilesystemSubscriptionImpl : public Config::Subscription,
                                   protected Logger::Loggable<Logger::Id::config> {
public:
  FilesystemSubscriptionImpl(Event::Dispatcher& dispatcher, absl::string_view path,
                             SubscriptionCallbacks& callbacks,
                             OpaqueResourceDecoder& resource_decoder, SubscriptionStats stats,
                             ProtobufMessage::ValidationVisitor& validation_visitor, Api::Api& api);

  // Config::Subscription
  // We report all discovered resources in the watched file, so the resource names arguments are
  // unused, and updateResourceInterest is a no-op (other than updating a stat).
  void start(const std::set<std::string>&, const bool use_namespace_matching = false) override;
  void updateResourceInterest(const std::set<std::string>&) override;
  void requestOnDemandUpdate(const std::set<std::string>&) override {
    NOT_IMPLEMENTED_GCOVR_EXCL_LINE;
  }

protected:
  virtual std::string refreshInternal(ProtobufTypes::MessagePtr* config_update);
  void refresh();
  void configRejected(const EnvoyException& e, const std::string& message);

  bool started_{};
  const std::string path_;
  std::unique_ptr<Filesystem::Watcher> watcher_;
  SubscriptionCallbacks& callbacks_;
  OpaqueResourceDecoder& resource_decoder_;
  SubscriptionStats stats_;
  Api::Api& api_;
  ProtobufMessage::ValidationVisitor& validation_visitor_;
};

// Currently a FilesystemSubscriptionImpl subclass, but this will need to change when we support
// non-inline collection resources.
class FilesystemCollectionSubscriptionImpl : public FilesystemSubscriptionImpl {
public:
  FilesystemCollectionSubscriptionImpl(Event::Dispatcher& dispatcher, absl::string_view path,
                                       SubscriptionCallbacks& callbacks,
                                       OpaqueResourceDecoder& resource_decoder,
                                       SubscriptionStats stats,
                                       ProtobufMessage::ValidationVisitor& validation_visitor,
                                       Api::Api& api);

  std::string refreshInternal(ProtobufTypes::MessagePtr* config_update) override;
};

} // namespace Config
} // namespace Envoy