/**
 *
 *  TimerQueue.h
 *  An Tao
 *
 *  Public header file in trantor lib.
 *
 *  Copyright 2018, An Tao.  All rights reserved.
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the License file.
 *
 *
 */

#pragma once

#include "timer.h"
#include <trantor/net/callbacks.h>
#include <atomic>
#include <memory>
#include <queue>
#include <unordered_set>

namespace trantor {
// class Timer;
class EventLoop;
class Channel;
using TimerPtr = std::shared_ptr<Timer>;
struct TimerPtrComparer {
	bool operator()(const TimerPtr &x, const TimerPtr &y) const {
		return *x > *y;
	}
};

class TimerQueue {
protected:
	TimerQueue(const TimerQueue &) = delete;
	TimerQueue &operator=(const TimerQueue &) = delete;
	// some uncopyable classes maybe support move constructor....
	TimerQueue(TimerQueue &&) noexcept(true) = default;
	TimerQueue &operator=(TimerQueue &&) noexcept(true) = default;

public:
	explicit TimerQueue(EventLoop *loop);
	~TimerQueue();
	TimerId addTimer(const TimerCallback &cb,
			const TimePoint &when,
			const TimeInterval &interval);
	TimerId addTimer(TimerCallback &&cb,
			const TimePoint &when,
			const TimeInterval &interval);
	void addTimerInLoop(const TimerPtr &timer);
	void invalidateTimer(TimerId id);
#ifdef __linux__
	void reset();
#else
	int64_t getTimeout() const;
	void processTimers();
#endif
protected:
	EventLoop *loop_;
#ifdef __linux__
	int timerfd_;
	std::shared_ptr<Channel> timerfdChannelPtr_;
	void handleRead();
#endif
	std::priority_queue<TimerPtr, std::vector<TimerPtr>, TimerPtrComparer>
			timers_;

	bool callingExpiredTimers_;
	bool insert(const TimerPtr &timePtr);
	std::vector<TimerPtr> getExpired();
	void reset(const std::vector<TimerPtr> &expired, const TimePoint &now);
	std::vector<TimerPtr> getExpired(const TimePoint &now);

private:
	std::unordered_set<uint64_t> timerIdSet_;
};
} // namespace trantor