#pragma once

#include <cstdint>

#include <list>

#include <string>

#include "envoy/api/api.h"

#include "envoy/event/dispatcher.h"

#include "envoy/filesystem/watcher.h"

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

#include "absl/container/node_hash_map.h"

namespace Envoy {

namespace Filesystem {

/**

 * Implementation of Watcher that uses inotify. inotify is an awful API. In order to make this work

 * in a somewhat sane way we always watch the directory that owns the thing being watched, and then

 * filter for events that are relevant to the thing being watched.

 */

class WatcherImpl : public Watcher, Logger::Loggable<Logger::Id::file> {

public:

  WatcherImpl(Event::Dispatcher& dispatcher, Filesystem::Instance& file_system);

  ~WatcherImpl() override;

  // Filesystem::Watcher

  absl::Status addWatch(absl::string_view path, uint32_t events, OnChangedCb cb) override;

private:

  struct FileWatch {

    std::string file_;

    uint32_t events_;

    OnChangedCb cb_;

  };

  struct DirectoryWatch {

    std::list<FileWatch> watches_;

  };

  absl::Status onInotifyEvent();

  void callAndLogOnError(OnChangedCb& cb, uint32_t events, const std::string& file);

  Filesystem::Instance& file_system_;

  int inotify_fd_;

  Event::FileEventPtr inotify_event_;

  absl::node_hash_map<int, DirectoryWatch> callback_map_;

};

} // namespace Filesystem

} // namespace Envoy