// ============================================================================
//  Copyright (C) 2001-2016 by Jozef Starosczyk
//  ixen@copyhandler.com
//
//  This program is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Library General Public License
//  (version 2) as published by the Free Software Foundation;
//
//  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 Library General Public
//  License along with this program; if not, write to the
//  Free Software Foundation, Inc.,
//  59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
// ============================================================================
#include "stdafx.h"
#include "TWriteBufferQueueWrapper.h"
#include "TOverlappedDataBuffer.h"
#include "TCoreException.h"

namespace chcore
{
	TWriteBufferQueueWrapper::TWriteBufferQueueWrapper(const TOrderedBufferQueuePtr& spQueue) :
		m_spDataQueue(spQueue),
		m_eventHasBuffers(true, false)
	{
		if (!spQueue)
			throw TCoreException(eErr_InvalidArgument, L"spQueue is NULL", LOCATION);

		UpdateHasBuffers();

		m_emptyBuffersQueueConnector = m_spDataQueue->GetNotifier().connect(boost::bind(&TWriteBufferQueueWrapper::UpdateHasBuffers, this, _1));
	}

	TWriteBufferQueueWrapper::~TWriteBufferQueueWrapper()
	{
		m_emptyBuffersQueueConnector.disconnect();
	}

	void TWriteBufferQueueWrapper::Push(TOverlappedDataBuffer* pBuffer)
	{
		if (!pBuffer)
			throw TCoreException(eErr_InvalidPointer, L"pBuffer", LOCATION);

		m_tRetryBuffers.Push(pBuffer);
		UpdateHasBuffers();
	}

	TOverlappedDataBuffer* TWriteBufferQueueWrapper::Pop()
	{
		TOverlappedDataBuffer* pBuffer = InternalPop();
		if(pBuffer)
		{
			pBuffer->InitForWrite();
			UpdateHasBuffers();
		}

		return pBuffer;
	}

	TOverlappedDataBuffer* TWriteBufferQueueWrapper::InternalPop()
	{
		const TOverlappedDataBuffer* pClaimedQueueBuffer = m_tRetryBuffers.Peek();
		if (!pClaimedQueueBuffer)
			return m_spDataQueue->Pop();

		const TOverlappedDataBuffer* pDataQueueBuffer = m_spDataQueue->Peek();
		if (!pDataQueueBuffer)
			return m_tRetryBuffers.Pop();

		if (pClaimedQueueBuffer->GetFilePosition() < pDataQueueBuffer->GetFilePosition())
			return m_tRetryBuffers.Pop();
		else
			return m_spDataQueue->Pop();
	}

	size_t TWriteBufferQueueWrapper::GetCount() const
	{
		return m_spDataQueue->GetCount();
	}

	HANDLE TWriteBufferQueueWrapper::GetHasBuffersEvent() const
	{
		return m_eventHasBuffers.Handle();
	}

	void TWriteBufferQueueWrapper::ClearBuffers(const TBufferListPtr& spEmptyBuffers)
	{
		m_spDataQueue->ClearBuffers(spEmptyBuffers);
		m_tRetryBuffers.ClearBuffers(spEmptyBuffers);
	}

	void TWriteBufferQueueWrapper::UpdateHasBuffers(bool bDataQueueHasPoppableBuffer)
	{
		bool bIsReady = bDataQueueHasPoppableBuffer || !m_tRetryBuffers.empty();
		m_eventHasBuffers.SetEvent(bIsReady);
	}

	void TWriteBufferQueueWrapper::UpdateHasBuffers()
	{
		UpdateHasBuffers(m_spDataQueue->HasPoppableBuffer());
	}
}