#pragma once

#include "envoy/common/optref.h"

#include "envoy/common/pure.h"

#include "envoy/config/extension_config_provider.h"

#include "envoy/network/filter.h"

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

#include "absl/types/optional.h"

namespace Envoy {

namespace Config {

using ConfigAppliedCb = std::function<void()>;

class DynamicExtensionConfigProviderBase {

public:

  /**

   * Update the provider with a new configuration. This interface accepts proto rather than a

   * factory callback so that it can be generic over factory types. If instantiating the factory

   * throws, it should only do so on the main thread, before any changes are applied to workers.

   * @param config is the new configuration. It is expected that the configuration has already been

   * validated.

   * @param version_info is the version of the new extension configuration.

   * @param cb the continuation callback for a completed configuration application on all threads.

   * @return an absl status indicating if a non-exception-throwing error was encountered.

   */

  virtual absl::Status onConfigUpdate(const Protobuf::Message& config,

                                      const std::string& version_info,

                                      ConfigAppliedCb applied_on_all_threads) PURE;

  /**

   * Removes the current configuration from the provider.

   * @param cb the continuation callback for a completed configuration application on all threads.

   * @return status indicating if the config was successfully removed.

   */

  virtual absl::Status onConfigRemoved(ConfigAppliedCb applied_on_all_threads) PURE;

  /**

   * Applies the default configuration if one is set, otherwise does nothing.

   */

  virtual absl::Status applyDefaultConfiguration() PURE;

  /**

   * Return Network::ListenerFilterMatcherSharedPtr& the listener filter matcher.

   */

  virtual const Network::ListenerFilterMatcherSharedPtr& getListenerFilterMatcher() PURE;

};

template <class FactoryCallback>

class DynamicExtensionConfigProvider : public DynamicExtensionConfigProviderBase,

                                       public ExtensionConfigProvider<FactoryCallback> {};

} // namespace Config

} // namespace Envoy