#include "global.h"
#include "RageSoundPosMap.h"
#include "RageLog.h"
#include "RageUtil.h"
#include "RageTimer.h"

#include <climits>
#include <cmath>
#include <cstdint>
#include <list>

// The number of frames we should keep pos_map data for.
// This comes out to about ~800kb in audio frames, assuming 44.1khz.
// File bitrate, metadata, etc will factor in here. If the queue is
// TOO big it will make things slow, but 200k frames is no problem.
// Making the queue larger than 200k hasn't been tested extensively.
const int pos_map_backlog_frames = 200000;

struct pos_map_t
{
	std::int64_t m_iSourceFrame;
	std::int64_t m_iDestFrame;
	std::int64_t m_iFrames;
	double m_fSourceToDestRatio;

	pos_map_t() { m_iSourceFrame = 0; m_iDestFrame = 0; m_iFrames = 0; m_fSourceToDestRatio = 1.0; }
};

struct pos_map_impl
{
	std::list<pos_map_t> m_Queue;
	void Cleanup();
};

pos_map_queue::pos_map_queue()
{
	m_pImpl = new pos_map_impl;
}

pos_map_queue::~pos_map_queue()
{
	delete m_pImpl;
}

pos_map_queue::pos_map_queue( const pos_map_queue &cpy )
{
	*this = cpy;
	m_pImpl = new pos_map_impl( *cpy.m_pImpl );
}

pos_map_queue &pos_map_queue::operator=( const pos_map_queue &rhs )
{
	if (this != &rhs)
	{
		pos_map_impl* tempImpl = new pos_map_impl(*rhs.m_pImpl);
		std::swap(m_pImpl, tempImpl);
		delete tempImpl;
	}
	return *this;
}

void pos_map_queue::Insert(std::int64_t iSourceFrame, std::int64_t iFrames, std::int64_t iDestFrame, double fSourceToDestRatio)
{
	bool merged = false;
	if (!m_pImpl->m_Queue.empty())
	{
		// Check if the last entry can be merged with the new entry
		pos_map_t& last = m_pImpl->m_Queue.back();
		if (last.m_iSourceFrame + last.m_iFrames == iSourceFrame &&
			last.m_fSourceToDestRatio == fSourceToDestRatio &&

			// llabs() is used instead of abs() because abs() would be susceptible to an integer overflow.
			llabs(last.m_iDestFrame + static_cast<int64_t>((last.m_iFrames * last.m_fSourceToDestRatio) + 0.5) - iDestFrame) <= 1)

		{
			// Merge the frames and set the merged flag to true.
			last.m_iFrames += iFrames;
			merged = true;
		}
	}

	if (!merged)
	{
		m_pImpl->m_Queue.push_back(pos_map_t());
		pos_map_t& m = m_pImpl->m_Queue.back();
		m.m_iSourceFrame = iSourceFrame;
		m.m_iDestFrame = iDestFrame;
		m.m_iFrames = iFrames;
		m.m_fSourceToDestRatio = fSourceToDestRatio;
	}

	m_pImpl->Cleanup();
}

void pos_map_impl::Cleanup()
{
	std::list<pos_map_t>::iterator it = m_Queue.end();
	std::int64_t iTotalFrames = 0;
	// Scan backwards until we have at least pos_map_backlog_frames.
	while (iTotalFrames < pos_map_backlog_frames)
	{
		if (it == m_Queue.begin())
			break;
		--it;
		iTotalFrames += it->m_iFrames;
	}

	m_Queue.erase(m_Queue.begin(), it);
}

std::int64_t pos_map_queue::Search( std::int64_t iSourceFrame ) const
{
	if( IsEmpty() )
	{
		return 0;
	}

	// iSourceFrame is probably in pos_map.  Search to figure out what position it maps to.
	std::int64_t iClosestPosition = 0, iClosestPositionDist = std::numeric_limits<int64_t>::max();
	for (pos_map_t const &pm : m_pImpl->m_Queue)
	{
		// Loop over the queue until we know generally where iSourceFrame is
		if( iSourceFrame >= pm.m_iSourceFrame &&
			iSourceFrame < pm.m_iSourceFrame+pm.m_iFrames )
		{
			// If we are in the correct block, calculate its current position
			std::int64_t iDiff = static_cast<std::int64_t>(iSourceFrame - pm.m_iSourceFrame);
			iDiff = static_cast<int64_t>(( iDiff * pm.m_fSourceToDestRatio) + 0.5 ); 
			return pm.m_iDestFrame + iDiff;
		}

		// See if the current position is close to the beginning of this block.
		std::int64_t dist = llabs( pm.m_iSourceFrame - iSourceFrame );
		if( dist < iClosestPositionDist )
		{
			iClosestPositionDist = dist;
			iClosestPosition = pm.m_iDestFrame;
		}

		// See if the current position is close to the end of this block.
		dist = llabs( pm.m_iSourceFrame + pm.m_iFrames - iSourceFrame );
		if( dist < iClosestPositionDist )
		{
			iClosestPositionDist = dist;
			iClosestPosition = pm.m_iDestFrame + static_cast<int64_t>((pm.m_iFrames * pm.m_fSourceToDestRatio) + 0.5 );
		}
	}

	/*
	 * The frame is out of the range of data we've actually sent.
	 * Return the closest position.
	 *
	 * There are three cases when this happens:
	 * 1. Before the first CommitPlayingPosition call.
	 * 2. After GetDataToPlay returns EOF and the sound has flushed, but before
	 *    SoundStopped has been called.
	 * 3. Underflow; we'll be given a larger frame number than we know about.
	 */
	static RageTimer last;
	if( last.PeekDeltaTime() >= 1.0f )
	{
		last.Touch();
		LOG->Trace("Audio frame was out of range of the data sent - possible buffer underflow? This is not always an error, however if you see it frequently there could be sound buffer problems.");
	}

	return iClosestPosition;
}

void pos_map_queue::Clear()
{
	m_pImpl->m_Queue.clear();
}

bool pos_map_queue::IsEmpty() const
{
	return m_pImpl->m_Queue.empty();
}

/*
 * Copyright (c) 2002-2004 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.
 */