/**
* Copyright (c) 2006-2011 LOVE Development Team
*
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
*    claim that you wrote the original software. If you use this software
*    in a product, an acknowledgment in the product documentation would be
*    appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
*    misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
**/

#include "threads.h"

namespace love
{
namespace thread
{

	Mutex::Mutex()
	{
		InitializeCriticalSection(&mutex);
	}

	Mutex::~Mutex()
	{
		DeleteCriticalSection(&mutex);
	}

	void Mutex::lock()
	{
		EnterCriticalSection(&mutex);
	}

	void Mutex::unlock()
	{
		LeaveCriticalSection(&mutex);
	}

	int ThreadBase::thread_runner(void* param)
	{
		ThreadBase* thread = (ThreadBase*)param;
		thread->main();
		return 0;
	}

	ThreadBase::ThreadBase()
		: running(false)
	{
	}

	ThreadBase::~ThreadBase()
	{
		if (running)
			wait();
	}

	bool ThreadBase::start()
	{
		thread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE) thread_runner, this, 0, NULL);
		if (thread == NULL)
			return false;
		else
			return (running = true);
	}

	void ThreadBase::wait()
	{
		WaitForSingleObject(thread, INFINITE);
		CloseHandle(thread);
		running = false;
	}

	void ThreadBase::kill()
	{
		TerminateThread(thread, FALSE);
		running = false;
	}

	unsigned int ThreadBase::threadId()
	{
		return (unsigned int)GetCurrentThreadId();
	}

	Semaphore::Semaphore(unsigned int initial_value)
		: count(initial_value)
	{
		semaphore = CreateSemaphore(NULL, initial_value, UINT_MAX, NULL);
	}

	Semaphore::~Semaphore()
	{
		CloseHandle(semaphore);
	}

	unsigned int Semaphore::value()
	{
		return count;
	}

	void Semaphore::post()
	{
		InterlockedIncrement(&count);
		if (ReleaseSemaphore(semaphore, 1, NULL) == FALSE)
			InterlockedDecrement(&count);
	}

	bool Semaphore::wait(int timeout)
	{
		int result;

		result = WaitForSingleObject(semaphore, timeout < 0 ? INFINITE : timeout);
		if (result == WAIT_OBJECT_0)
		{
			InterlockedDecrement(&count);
			return true;
		}
		else
			return false;
	}

	bool Semaphore::tryWait()
	{
		return wait(0);
	}


	// Conditional variable implementation based on semaphores.
	// Vista+ builds should probably use CONDITIONAL_VARIABLE.
	//
	// based on http://www.cs.wustl.edu/~schmidt/win32-cv-2.html and ACE


	Conditional::Conditional()
		: waiting(0), signals(0)
	{
	}

	Conditional::~Conditional()
	{
	}

	void Conditional::signal()
	{
		mutex.lock();
		if (waiting > signals)
		{
			signals++;
			sem.post();
			mutex.unlock();
			done.wait();
		}
		else
		{
			mutex.unlock();
		}
	}

	void Conditional::broadcast()
	{
		mutex.lock();
		if (waiting > signals)
		{
			int num = waiting - signals;
			signals = waiting;
			for (int i = 0; i < num; i++)
				sem.post();
			mutex.unlock();
			for (int i = 0; i < num; i++)
				done.wait();
		}
		else
		{
			mutex.unlock();
		}
	}

	bool Conditional::wait(Mutex* cmutex, int timeout)
	{
		mutex.lock();
		waiting++;
		mutex.unlock();

		cmutex->unlock();
		bool ret = sem.wait(timeout);

		mutex.lock();
		if (signals > 0)
		{
			if (!ret)
				sem.wait();
			done.post();
			signals--;
		}
		waiting--;
		mutex.unlock();
		cmutex->lock();
		
		return true;
	}

} // thread
} // love