/*
 * Copyright (c) 2017-2019 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <hicn/transport/utils/event_reactor.h>
#include <hicn/transport/utils/spinlock.h>

#include <sys/epoll.h>
#include <atomic>
#include <cstddef>
#include <functional>
#include <mutex>
#include <unordered_map>

#define FD_NUMBER 20000

namespace utils {

typedef struct epoll_event Event;
typedef std::function<int(const Event &)> EventCallback;
typedef std::unordered_map<int, EventCallback> EventCallbackMap;

class EpollEventReactor : public EventReactor {
 public:
  explicit EpollEventReactor();

  ~EpollEventReactor();

  template <typename EventHandler>
  int addFileDescriptor(int fd, uint32_t events, EventHandler &&callback) {
    auto it = event_callback_map_.find(fd);
    int ret = 0;

    if (it == event_callback_map_.end()) {
      {
        utils::SpinLock::Acquire locked(event_callback_map_lock_);
        event_callback_map_[fd] = std::forward<EventHandler &&>(callback);
      }

      ret = addFileDescriptor(fd, events);
    }

    return ret;
  }

  int delFileDescriptor(int fd);

  int modFileDescriptor(int fd, uint32_t events);

  void runEventLoop(int timeout = -1) override;

  void runOneEvent() override;

  void stop() override;

  std::size_t mapSize();

 private:
  int addFileDescriptor(int fd, uint32_t events);

  int epoll_fd_;
  std::atomic_bool run_event_loop_;
  EventCallbackMap event_callback_map_;
  utils::SpinLock event_callback_map_lock_;
};

}  // namespace utils