/**
 * Tibia GIMUD Server - a free and open-source MMORPG server emulator
 * Copyright (C) 2019 Sabrehaven and Mark Samman <mark.samman@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef FS_SCHEDULER_H_2905B3D5EAB34B4BA8830167262D2DC1
#define FS_SCHEDULER_H_2905B3D5EAB34B4BA8830167262D2DC1

#include "tasks.h"
#include <unordered_set>
#include <queue>

#include "thread_holder_base.h"

static constexpr int32_t SCHEDULER_MINTICKS = 50;

class SchedulerTask : public Task
{
	public:
		void setEventId(uint32_t id) {
			eventId = id;
		}
		uint32_t getEventId() const {
			return eventId;
		}

		std::chrono::system_clock::time_point getCycle() const {
			return expiration;
		}

	protected:
		SchedulerTask(uint32_t delay, const std::function<void (void)>& f) : Task(delay, f) {}

		uint32_t eventId = 0;

		friend SchedulerTask* createSchedulerTask(uint32_t, const std::function<void (void)>&);
};

inline SchedulerTask* createSchedulerTask(uint32_t delay, const std::function<void (void)>& f)
{
	return new SchedulerTask(delay, f);
}

struct TaskComparator {
	bool operator()(const SchedulerTask* lhs, const SchedulerTask* rhs) const {
		return lhs->getCycle() > rhs->getCycle();
	}
};

class Scheduler : public ThreadHolder<Scheduler>
{
	public:
		uint32_t addEvent(SchedulerTask* task);
		bool stopEvent(uint32_t eventId);

		void shutdown();

		void threadMain();
	protected:
		std::thread thread;
		std::mutex eventLock;
		std::condition_variable eventSignal;

		uint32_t lastEventId {0};
		std::priority_queue<SchedulerTask*, std::deque<SchedulerTask*>, TaskComparator> eventList;
		std::unordered_set<uint32_t> eventIds;
};

extern Scheduler g_scheduler;

#endif