//! \file pithreadpoolexecutor.h
//! \ingroup Thread
//! \brief
//! \~english Thread pool executor
//! \~russian Исполнитель пула потоков
//!
//! \details
//! \~english Executes tasks in a pool of worker threads.
//! \~russian Выполняет задачи в пуле рабочих потоков.
/*
    PIP - Platform Independent Primitives

    Stephan Fomenko

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 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 Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef PITHREADPOOLEXECUTOR_H
#define PITHREADPOOLEXECUTOR_H

#include "piblockingqueue.h"
#include "pithread.h"

#include <atomic>


//! \~english Thread pool executor for running tasks
//! \~russian Исполнитель пула потоков для выполнения задач
class PIP_EXPORT PIThreadPoolExecutor {
public:
	//! \~english Constructs executor with core pool size
	//! \~russian Создает исполнитель с размером ядра пула
	explicit PIThreadPoolExecutor(int corePoolSize);

	//! \~english Destroys executor
	//! \~russian Уничтожает исполнитель
	virtual ~PIThreadPoolExecutor();

	//! \brief Executes the given task sometime in the future. The task execute in an existing pooled thread. If the task
	//! cannot be submitted for execution, either because this executor has been shutdown or because its capacity has been
	//! reached.
	//!
	//! \param runnable not empty function for thread pool execution
	//! \~english Execute task in thread pool
	//! \~russian Выполняет задачу в пуле потоков
	void execute(const std::function<void()> & runnable);

	//! \~english Stop all threads immediately
	//! \~russian Немедленно останавливает все потоки
	void shutdownNow();

	//! \brief Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be
	//! accepted. Invocation has no additional effect if already shut down. This method does not wait for previously
	//! submitted tasks to complete execution. Use awaitTermination to do that.
	//! \~english Initiates orderly shutdown
	//! \~russian Инициирует упорядоченное завершение
	void shutdown();

	//! \~english Returns if executor is shutdown
	//! \~russian Возвращает остановлен ли исполнитель
	bool isShutdown() const;

	//! \~english Wait for termination
	//! \~russian Ожидает завершения
	bool awaitTermination(PISystemTime timeout);

private:
	std::atomic_bool isShutdown_;
	PIBlockingQueue<std::function<void()>> taskQueue;
	PIVector<PIThread *> threadPool;
};

#endif // PITHREADPOOLEXECUTOR_H