/*
 * Copyright 2009, Haiku, Inc. All Rights Reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *		Clemens Zeidler, haiku@Clemens-Zeidler.de
 */


#include "DriverInterface.h"

#include <Autolock.h>
#include <Messenger.h>


Monitor::~Monitor()
{
}


status_t
Monitor::StartWatching(BHandler* target)
{
	if (fWatcherList.HasItem(target))
		return B_ERROR;

	fWatcherList.AddItem(target);
	return B_OK;
}


status_t
Monitor::StopWatching(BHandler* target)
{
	return fWatcherList.RemoveItem(target);
}


void
Monitor::Broadcast(uint32 message)
{
	for (int i = 0; i < fWatcherList.CountItems(); i++) {
		BMessenger messenger(fWatcherList.ItemAt(i));
		messenger.SendMessage(message);
	}
}


//	#pragma mark -


PowerStatusDriverInterface::PowerStatusDriverInterface()
	:
	fIsWatching(0),
	fWaitSem(-1),
	fThread(-1)
{
}


PowerStatusDriverInterface::~PowerStatusDriverInterface()
{
}


status_t
PowerStatusDriverInterface::StartWatching(BHandler* target)
{
	BAutolock autolock(fListLocker);

	status_t status = Monitor::StartWatching(target);
	if (status != B_OK)
		return status;

	if (fThread > 0)
		return B_OK;

	fThread = spawn_thread(&_ThreadWatchPowerFunction, "PowerStatusThread",
		B_LOW_PRIORITY, this);
	if (fThread >= 0) {
		fWaitSem = create_sem(0, "power status wait");

		atomic_set(&fIsWatching, 1);
		status = resume_thread(fThread);
	} else
		return fThread;

	if (status != B_OK && fWatcherList.CountItems() == 0) {
		atomic_set(&fIsWatching, 0);
		delete_sem(fWaitSem);

		fThread = -1;
		fWaitSem = -1;
	}

	return status;
}


status_t
PowerStatusDriverInterface::StopWatching(BHandler* target)
{
	if (fThread < 0)
		return B_BAD_VALUE;

	fListLocker.Lock();

	if (fWatcherList.CountItems() == 1) {
		fListLocker.Unlock();
		Disconnect();
	} else
		fListLocker.Unlock();

	return Monitor::StopWatching(target);
}


void
PowerStatusDriverInterface::Broadcast(uint32 message)
{
	BAutolock autolock(fListLocker);
	Monitor::Broadcast(message);
}


void
PowerStatusDriverInterface::Disconnect()
{
	if (fThread < 0)
		return;

	atomic_set(&fIsWatching, 0);
	delete_sem(fWaitSem);

	wait_for_thread(fThread, NULL);
	fThread = -1;
	fWaitSem = -1;
}


int32
PowerStatusDriverInterface::_ThreadWatchPowerFunction(void* data)
{
	PowerStatusDriverInterface* that = (PowerStatusDriverInterface*)data;
	that->_WatchPowerStatus();
	return 0;
}