#include "global.h"
#include "RageSoundReader_SpeedChange.h"
#include "RageSoundReader_Resample_Good.h"
#include "RageUtil.h"
#include "RageLog.h"

static const int WINDOW_SIZE_MS = 30;

RageSoundReader_SpeedChange::RageSoundReader_SpeedChange( RageSoundReader *pSource ):
	RageSoundReader_Filter( pSource )
{
	m_Channels.resize( pSource->GetNumChannels() );
	SetSpeedRatio( 1.3f );
	Reset();
}

void RageSoundReader_SpeedChange::SetSpeedRatio( float fRatio )
{
	fSpeed = fRatio;
	m_iDeltaFrames = lrintf( GetWindowSizeFrames() * fRatio );

	/* If we havn't read any data yet, put the new delta into effect immediately. */
	if( m_iDataBufferAvailFrames == 0 )
		m_iTrailingDeltaFrames = m_iDeltaFrames;
}

float RageSoundReader_SpeedChange::GetRatio() const
{
	return float(m_iDeltaFrames) / GetWindowSizeFrames();
}

int RageSoundReader_SpeedChange::GetWindowSizeFrames() const
{
	return (WINDOW_SIZE_MS * GetSampleRate()) / 1000;
}

float RageSoundReader_SpeedChange::GetTrailingRatio() const
{
	return float(m_iTrailingDeltaFrames) / GetWindowSizeFrames();
}

void RageSoundReader_SpeedChange::Reset()
{
	m_iTrailingDeltaFrames = m_iDeltaFrames;
	m_iDataBufferAvailFrames = 0;
	for( size_t i = 0; i < m_Channels.size(); ++i )
	{
		ChannelInfo &c = m_Channels[i];
		c.m_iCorrelatedPos = 0;
		c.m_iLastCorrelatedPos = 0;
	}
	m_iUncorrelatedPos = 0;
	m_iPos = 0;
}

static int FindClosestMatch( const int16_t *pBuffer, int iBufferSize, const int16_t *pCorrelateBuffer, int iCorrelateBufferSize, int iStride )
{
	if( iBufferSize <= iCorrelateBufferSize )
		return 0;

	/* Optimization: if the buffers are the same, they always corellate at 0. */
	if( pBuffer == pCorrelateBuffer )
		return 0;

	int iBufferDistanceToSearch = iBufferSize - iCorrelateBufferSize;
	int iBestOffset = 0;
	int iBestScore = 0;
	for( int i = 0; i < iBufferDistanceToSearch; i += iStride )
	{
		int iScore = 0;
		const int16_t *pFrames = pBuffer + i;
		for( int j = 0; j < iCorrelateBufferSize; j += iStride )
		{
			int iDiff = pFrames[j] - pCorrelateBuffer[j];
			iScore += abs(iDiff);
		}

		if( i == 0 || iScore < iBestScore )
		{
			iBestScore = iScore;
			iBestOffset = i;
		}
	}
	return iBestOffset;
}

int RageSoundReader_SpeedChange::FillData( int iMaxFrames )
{
	/* XXX: If the rate or source frame offset changes in the source, we should stop
	 * at that point, so the changes propagate upward.  That's tricky, since we want
	 * to process a block at a time.  We could just flush what we have, and maybe
	 * tweak m_iDeltaFrames for the next block based on how much we processed, so
	 * we average out the short block. */
	while( iMaxFrames > 0 )
	{
		int iFramesToRead = iMaxFrames - m_iDataBufferAvailFrames;
		int iBytesToRead = iFramesToRead * m_Channels.size() * sizeof(int16_t);
		if( iBytesToRead <= 0 )
			return m_iDataBufferAvailFrames;

		int16_t *pTempBuffer = (int16_t *) alloca( iBytesToRead );
		int iGotFrames = m_pSource->Read( (char *) pTempBuffer, iFramesToRead );
		if( iGotFrames < 0 )
		{
			if( iGotFrames == END_OF_FILE && m_iDataBufferAvailFrames )
				return m_iDataBufferAvailFrames;
			return iGotFrames;
		}

		for( size_t i = 0; i < m_Channels.size(); ++i )
		{
			ChannelInfo &c = m_Channels[i];

			if( (int) c.m_DataBuffer.size() < iMaxFrames )
				c.m_DataBuffer.resize( iMaxFrames );

			const int16_t *pIn = pTempBuffer + i;
			int16_t *pOut = &c.m_DataBuffer[m_iDataBufferAvailFrames];
			for( int j = 0; j < iGotFrames; ++j )
			{
				*pOut = *pIn;
				pIn += m_Channels.size();
				++pOut;
			}
		}

		m_iDataBufferAvailFrames += iGotFrames;
	}
	return m_iDataBufferAvailFrames;
}

void RageSoundReader_SpeedChange::EraseData( int iFramesToDelete )
{
	ASSERT( iFramesToDelete <= m_iDataBufferAvailFrames );
	ASSERT( m_iDataBufferAvailFrames >= iFramesToDelete );
	ASSERT( m_iUncorrelatedPos >= iFramesToDelete );

	int iFramesToMove = m_iDataBufferAvailFrames - iFramesToDelete;
	m_iDataBufferAvailFrames -= iFramesToDelete;
	m_iUncorrelatedPos -= iFramesToDelete;
	for( size_t i = 0; i < m_Channels.size(); ++i )
	{
		ChannelInfo &c = m_Channels[i];
		if( iFramesToMove )
			memmove( &c.m_DataBuffer[0], &c.m_DataBuffer[iFramesToDelete], iFramesToMove * sizeof(int16_t) );
		ASSERT( c.m_iCorrelatedPos >= iFramesToDelete );
		c.m_iCorrelatedPos -= iFramesToDelete;
	}
}

int RageSoundReader_SpeedChange::Step()
{
	if( m_iDataBufferAvailFrames == 0 )
		return FillData( GetWindowSizeFrames() );

	/* If m_iPos is non-zero, we just finished playing a previous block, so advance forward. */
	if( m_iPos )
	{
		/* Advance m_iCorrelatedPos past the data that was just copied, to point to the
		 * sound that we would have played if we had continued copying at that point. */
		for( size_t i = 0; i < m_Channels.size(); ++i )
		{
			ASSERT( m_Channels[i].m_iCorrelatedPos + m_iPos <= m_iDataBufferAvailFrames );
			m_Channels[i].m_iCorrelatedPos += m_iPos;
		}

		/* Advance m_iUncorrelatedPos to the position we'd prefer to continue playing from. */
		m_iUncorrelatedPos += m_iTrailingDeltaFrames;

		m_iPos = 0;
	}

	m_iTrailingDeltaFrames = m_iDeltaFrames;

	/* We don't need any data before the earlier of m_iUncorrelatedPos or m_iCorrelatedPos. */
	int iToDelete = m_iUncorrelatedPos;
	for( size_t i = 0; i < m_Channels.size(); ++i )
	{
		ChannelInfo &c = m_Channels[i];
		ASSERT( c.m_iCorrelatedPos <= m_iDataBufferAvailFrames );
		iToDelete = min( iToDelete, c.m_iCorrelatedPos );
		//iToDelete = min( iToDelete, m_iDataBufferAvailFrames );
	}
	EraseData( iToDelete );

	/* Fill as much data as we might need to do the search and use the result. */
	{
		int iMaxPositionNeeded = m_iUncorrelatedPos + GetToleranceFrames() + GetWindowSizeFrames();
		for( size_t i = 0; i < m_Channels.size(); ++i )
			iMaxPositionNeeded = max( iMaxPositionNeeded, m_Channels[i].m_iCorrelatedPos + GetWindowSizeFrames() );

		int iGot = FillData( iMaxPositionNeeded );
		if( iGot < 0 )
			return iGot;

		if( iMaxPositionNeeded > m_iDataBufferAvailFrames )
		{
			/* We're at EOF.  Flush the remaining data, if any. */
			m_iUncorrelatedPos = m_Channels[0].m_iCorrelatedPos;
			return m_iDataBufferAvailFrames;
		}
	}

	/* Starting at our preferred position (m_iUncorrelatedPos), within GetToleranceFrames(),
	 * search for data that looks like the sound we would have continued playing if we
	 * kept going from the old position (m_iCorrelatedPos). */
	int iCorrelatedToMatch = GetWindowSizeFrames()/4;
	int iUncorrelatedToMatch = GetToleranceFrames() + iCorrelatedToMatch; // maximum distance to search

	for( size_t i = 0; i < m_Channels.size(); ++i )
	{
		ChannelInfo &c = m_Channels[i];
		ASSERT( c.m_iCorrelatedPos >= 0 );
		ASSERT( c.m_iCorrelatedPos < m_iDataBufferAvailFrames );

		int iBest = FindClosestMatch( &c.m_DataBuffer[m_iUncorrelatedPos], iUncorrelatedToMatch, &c.m_DataBuffer[c.m_iCorrelatedPos], iCorrelatedToMatch, m_Channels.size() );
		c.m_iLastCorrelatedPos = c.m_iCorrelatedPos;
		c.m_iCorrelatedPos = iBest + m_iUncorrelatedPos;
		ASSERT( m_Channels[i].m_iCorrelatedPos + GetWindowSizeFrames() <= m_iDataBufferAvailFrames );
	}
	return m_iDataBufferAvailFrames;
}

int RageSoundReader_SpeedChange::GetCursorAvail() const
{
	int iCursorAvail = GetWindowSizeFrames() - m_iPos;
	for( size_t i = 0; i < m_Channels.size(); ++i )
	{
		int iCursorAvailForChannel = (m_iDataBufferAvailFrames-m_Channels[i].m_iCorrelatedPos) - m_iPos;
		iCursorAvail = min( iCursorAvail, iCursorAvailForChannel );
	}

	return iCursorAvail;
}

int RageSoundReader_SpeedChange::Read( char *buf, int iFrames )
{
	int16_t *pBuf = (int16_t *) buf;

	while( 1 )
	{
		// m_iDataBufferAvailFrames-m_iCorrelatedPos < GetWindowSizeFrames when flushing
		int iCursorAvail = GetCursorAvail();

		if( iCursorAvail == 0 && m_iTrailingDeltaFrames == m_iDeltaFrames && GetWindowSizeFrames() == m_iDeltaFrames )
		{
			/* Fast path: the buffer is empty, and we're not scaling the audio.  Read directly
			 * into the output buffer, to eliminate memory and copying overhead. */
			return m_pSource->Read( (char *) pBuf, iFrames );
		}

		if( iCursorAvail == 0 )
		{
			int iRet = Step();
			if( iRet < 0 )
				return iRet;
			if( !GetCursorAvail() )
				return END_OF_FILE;
			continue;
		}

		/* copy GetWindowSizeFrames() from iCorrelatedPos */
		int iFramesLen = iFrames;
		int iFramesAvail = min( iCursorAvail, iFramesLen );

		iFrames -= iFramesAvail;
		int iFramesRead = iFramesAvail;

		int iWindowSizeFrames = GetWindowSizeFrames();
		while( iFramesAvail-- )
		{
			for( size_t i = 0; i < m_Channels.size(); ++i )
			{
				ChannelInfo &c = m_Channels[i];
				int i1 = c.m_DataBuffer[c.m_iCorrelatedPos+m_iPos];
				int i2 = c.m_DataBuffer[c.m_iLastCorrelatedPos+m_iPos];
				*pBuf++ = int16_t( SCALE( m_iPos, 0, iWindowSizeFrames, i2, i1 ) );
			}

			++m_iPos;
		}

		return iFramesRead;
	}
}

/* We prefer to be able to seek precisely, so seeking to a position produces data
 * equal to what you'd get if you read data up to that point.  This filter can't do
 * that, because the exact selection of slices is dependent on the previous selection. */
int RageSoundReader_SpeedChange::SetPosition( int iFrame )
{
	Reset();
	
	int64_t iScaled = (int64_t(iFrame) * GetWindowSizeFrames()) / m_iDeltaFrames;
	iFrame = (int) iScaled;

	return RageSoundReader_Filter::SetPosition( iFrame );
}

bool RageSoundReader_SpeedChange::SetProperty( const RString &sProperty, float fValue )
{
	if( sProperty == "Speed" )
	{
		SetSpeedRatio( fValue );
		return true;
	}

	return RageSoundReader_Filter::SetProperty( sProperty, fValue );
}

int RageSoundReader_SpeedChange::GetNextSourceFrame() const
{
	float fRatio = GetTrailingRatio();

	int iSourceFrame = RageSoundReader_Filter::GetNextSourceFrame();
	int iPos = lrintf(m_iPos * fRatio);

	iSourceFrame -= m_iDataBufferAvailFrames;
	iSourceFrame += m_iUncorrelatedPos + iPos;
	return iSourceFrame;
}

float RageSoundReader_SpeedChange::GetStreamToSourceRatio() const
{
	/* If the ratio has changed and GetCursorAvail() is 0, the new ratio will
	 * become the real ratio on the next read.  Otherwise, we'll continue using
	 * our old ratio for a bit longer. */
	if( GetCursorAvail() == 0 )
		return GetRatio() * RageSoundReader_Filter::GetStreamToSourceRatio();
	else
		return GetTrailingRatio() * RageSoundReader_Filter::GetStreamToSourceRatio();
}

/*
 * Copyright (c) 2006 Glenn Maynard
 * All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, and/or sell copies of the Software, and to permit persons to
 * whom the Software is furnished to do so, provided that the above
 * copyright notice(s) and this permission notice appear in all copies of
 * the Software and that both the above copyright notice(s) and this
 * permission notice appear in supporting documentation.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
 * THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
 * INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
 * OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */