/*
** music_libsndfile.cpp
** Uses libsndfile for streaming music formats
**
**---------------------------------------------------------------------------
** Copyright 2017 Christoph Oelckers
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
**    derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/

// HEADER FILES ------------------------------------------------------------

#include <mutex>
#include "i_musicinterns.h"
#include "c_cvars.h"
#include "v_text.h"
#include "templates.h"
#include "m_fixed.h"
#include "streamsource.h"

// MACROS ------------------------------------------------------------------

// TYPES -------------------------------------------------------------------

class SndFileSong : public StreamSource
{
public:
	SndFileSong(FileReader &reader, SoundDecoder *decoder, uint32_t loop_start, uint32_t loop_end, bool startass, bool endass);
	~SndFileSong();
	std::string GetStats() override;
	SoundStreamInfo GetFormat() override;
	bool GetData(void *buffer, size_t len) override;
	
protected:
	std::mutex CritSec;
	FileReader Reader;
	SoundDecoder *Decoder;
	int Channels;
	int SampleRate;
	
	uint32_t Loop_Start;
	uint32_t Loop_End;

	int CalcSongLength();
};

// EXTERNAL FUNCTION PROTOTYPES --------------------------------------------

// PUBLIC FUNCTION PROTOTYPES ----------------------------------------------

// PRIVATE FUNCTION PROTOTYPES ---------------------------------------------

// EXTERNAL DATA DECLARATIONS ----------------------------------------------

// PUBLIC DATA DEFINITIONS -------------------------------------------------

CUSTOM_CVAR(Int, snd_streambuffersize, 64, CVAR_ARCHIVE | CVAR_GLOBALCONFIG)
{
	if (self < 16)
	{
		self = 16;
	}
	else if (self > 1024)
	{
		self = 1024;
	}
}

// PRIVATE DATA DEFINITIONS ------------------------------------------------

// CODE --------------------------------------------------------------------

//==========================================================================
//
// Try to find the LOOP_START/LOOP_END tags in a Vorbis Comment block
//
// We have to parse through the FLAC or Ogg headers manually, since sndfile
// doesn't provide proper access to the comments and we'd rather not require
// using libFLAC and libvorbisfile directly.
//
//==========================================================================

static void ParseVorbisComments(FileReader &fr, uint32_t *start, bool *startass, uint32_t *end, bool *endass)
{
	uint8_t vc_data[4];

	// The VC block starts with a 32LE integer for the vendor string length,
	// followed by the vendor string
	if(fr.Read(vc_data, 4) != 4)
		return;
	uint32_t vndr_len = vc_data[0] | (vc_data[1]<<8) | (vc_data[2]<<16) | (vc_data[3]<<24);

	// Skip vendor string
	if(fr.Seek(vndr_len, FileReader::SeekCur) == -1)
		return;

	// Following the vendor string is a 32LE integer for the number of
	// comments, followed by each comment.
	if(fr.Read(vc_data, 4) != 4)
		return;
	size_t count = vc_data[0] | (vc_data[1]<<8) | (vc_data[2]<<16) | (vc_data[3]<<24);

	for(size_t i = 0; i < count; i++)
	{
		// Each comment is a 32LE integer for the comment length, followed by
		// the comment text (not null terminated!)
		if(fr.Read(vc_data, 4) != 4)
			return;
		uint32_t length = vc_data[0] | (vc_data[1]<<8) | (vc_data[2]<<16) | (vc_data[3]<<24);

		if(length >= 128)
		{
			// If the comment is "big", skip it
			if(fr.Seek(length, FileReader::SeekCur) == -1)
				return;
			continue;
		}

		char strdat[128];
		if(fr.Read(strdat, length) != (long)length)
			return;
		strdat[length] = 0;

		if(strnicmp(strdat, "LOOP_START=", 11) == 0)
			S_ParseTimeTag(strdat + 11, startass, start);
		else if(strnicmp(strdat, "LOOP_END=", 9) == 0)
			S_ParseTimeTag(strdat + 9, endass, end);
	}
}

static void FindFlacComments(FileReader &fr, uint32_t *loop_start, bool *startass, uint32_t *loop_end, bool *endass)
{
	// Already verified the fLaC marker, so we're 4 bytes into the file
	bool lastblock = false;
	uint8_t header[4];

	while(!lastblock && fr.Read(header, 4) == 4)
	{
		// The first byte of the block header contains the type and a flag
		// indicating the last metadata block
		char blocktype = header[0]&0x7f;
		lastblock = !!(header[0]&0x80);
		// Following the type is a 24BE integer for the size of the block
		uint32_t blocksize = (header[1]<<16) | (header[2]<<8) | header[3];

		// FLAC__METADATA_TYPE_VORBIS_COMMENT is 4
		if(blocktype == 4)
		{
			ParseVorbisComments(fr, loop_start, startass, loop_end, endass);
			return;
		}

		if(fr.Seek(blocksize, FileReader::SeekCur) == -1)
			break;
	}
}

static void FindOggComments(FileReader &fr, uint32_t *loop_start, bool *startass, uint32_t *loop_end, bool *endass)
{
	uint8_t ogghead[27];

	// We already read and verified the OggS marker, so skip the first 4 bytes
	// of the Ogg page header.
	while(fr.Read(ogghead+4, 23) == 23)
	{
		// The 19th byte of the Ogg header is a 32LE integer for the page
		// number, and the 27th is a uint8 for the number of segments in the
		// page.
		uint32_t ogg_pagenum = ogghead[18] | (ogghead[19]<<8) | (ogghead[20]<<16) |
		                       (ogghead[21]<<24);
		uint8_t ogg_segments = ogghead[26];

		// Following the Ogg page header is a series of uint8s for the length of
		// each segment in the page. The page segment data follows contiguously
		// after.
		uint8_t segsizes[256];
		if(fr.Read(segsizes, ogg_segments) != ogg_segments)
			break;

		// Find the segment with the Vorbis Comment packet (type 3)
		for(int i = 0; i < ogg_segments; ++i)
		{
			uint8_t segsize = segsizes[i];

			if(segsize > 16)
			{
				uint8_t vorbhead[7];
				if(fr.Read(vorbhead, 7) != 7)
					return;

				if(vorbhead[0] == 3 && memcmp(vorbhead+1, "vorbis", 6) == 0)
				{
					// If the packet is 'laced', it spans multiple segments (a
					// segment size of 255 indicates the next segment continues
					// the packet, ending with a size less than 255). Vorbis
					// packets always start and end on segment boundaries. A
					// packet that's an exact multiple of 255 ends with a
					// segment of 0 size.
					while(segsize == 255 && ++i < ogg_segments)
						segsize = segsizes[i];

					// TODO: A Vorbis packet can theoretically span multiple
					// Ogg pages (e.g. start in the last segment of one page
					// and end in the first segment of a following page). That
					// will require extra logic to decode as the VC block will
					// be broken up with non-Vorbis data in-between. For now,
					// just handle the common case where it's all in one page.
					if(i < ogg_segments)
						ParseVorbisComments(fr, loop_start, startass, loop_end, endass);
					return;
				}

				segsize -= 7;
			}
			if(fr.Seek(segsize, FileReader::SeekCur) == -1)
				return;
		}

		// Don't keep looking after the third page
		if(ogg_pagenum >= 2)
			break;

		if(fr.Read(ogghead, 4) != 4 || memcmp(ogghead, "OggS", 4) != 0)
			break;
	}
}

void FindLoopTags(FileReader &fr, uint32_t *start, bool *startass, uint32_t *end, bool *endass)
{
	uint8_t signature[4];

	fr.Read(signature, 4);
	if(memcmp(signature, "fLaC", 4) == 0)
		FindFlacComments(fr, start, startass, end, endass);
	else if(memcmp(signature, "OggS", 4) == 0)
		FindOggComments(fr, start, startass, end, endass);
}


//==========================================================================
//
// SndFile_OpenSong
//
//==========================================================================

StreamSource *SndFile_OpenSong(FileReader &fr)
{
	fr.Seek(0, FileReader::SeekSet);

	uint32_t loop_start = 0, loop_end = ~0u;
	bool startass = false, endass = false;
	FindLoopTags(fr, &loop_start, &startass, &loop_end, &endass);

	fr.Seek(0, FileReader::SeekSet);
	auto decoder = SoundRenderer::CreateDecoder(fr);
	if (decoder == nullptr) return nullptr;
	return new SndFileSong(fr, decoder, loop_start, loop_end, startass, endass);
}

//==========================================================================
//
// SndFileSong - Constructor
//
//==========================================================================

SndFileSong::SndFileSong(FileReader &reader, SoundDecoder *decoder, uint32_t loop_start, uint32_t loop_end, bool startass, bool endass)
{
	ChannelConfig iChannels;
	SampleType Type;
	
	decoder->getInfo(&SampleRate, &iChannels, &Type);

	if (!startass) loop_start = Scale(loop_start, SampleRate, 1000);
	if (!endass) loop_end = Scale(loop_end, SampleRate, 1000);

	const uint32_t sampleLength = (uint32_t)decoder->getSampleLength();
	Loop_Start = loop_start;
	Loop_End = sampleLength == 0 ? loop_end : clamp<uint32_t>(loop_end, 0, sampleLength);
	Reader = std::move(reader);
	Decoder = decoder;
	Channels = iChannels == ChannelConfig_Stereo? 2:1;
}

SoundStreamInfo SndFileSong::GetFormat()
{
	return { snd_streambuffersize * 1024, SampleRate, -Channels };
}

//==========================================================================
//
// SndFileSong - Destructor
//
//==========================================================================

SndFileSong::~SndFileSong()
{
	if (Decoder != nullptr)
	{
		delete Decoder;
	}
}

//==========================================================================
//
// SndFileSong :: GetStats
//
//==========================================================================

std::string SndFileSong::GetStats()
{
	char out[80];
	
	size_t SamplePos;
	
	SamplePos = Decoder->getSampleOffset();
	int time = int (SamplePos / SampleRate);
	
	snprintf(out, 80,
		"Track: %s, %dHz  Time: %02d:%02d",
		Channels == 2? "Stereo" : "Mono", SampleRate,
		time/60,
		time % 60);
	return out;
}

//==========================================================================
//
// SndFileSong :: Read													STATIC
//
//==========================================================================

bool SndFileSong::GetData(void *vbuff, size_t len)
{
	char *buff = (char*)vbuff;
	std::lock_guard<std::mutex> lock(CritSec);
	
	size_t currentpos = Decoder->getSampleOffset();
	size_t framestoread = len / (Channels*2);
	bool err = false;
	if (!m_Looping)
	{
		size_t maxpos = Decoder->getSampleLength();
		if (currentpos == maxpos)
		{
			memset(buff, 0, len);
			return false;
		}
		if (currentpos + framestoread > maxpos)
		{
			size_t got = Decoder->read(buff, (maxpos - currentpos) * Channels * 2);
			memset(buff + got, 0, len - got);
		}
		else
		{
			size_t got = Decoder->read(buff, len);
			err = (got != len);
		}
	}
	else
	{
		// This looks a bit more complicated than necessary because libmpg123 will not read the full requested length for the last block in the file.
		if (currentpos + framestoread > Loop_End)
		{
			// Loop can be very short, make sure the current position doesn't exceed it
			if (currentpos < Loop_End)
			{
				size_t endblock = (Loop_End - currentpos) * Channels * 2;
				size_t endlen = Decoder->read(buff, endblock);

				// Even if zero bytes was read give it a chance to start from the beginning
				buff += endlen;
				len -= endlen;
			}

			Decoder->seek(Loop_Start, false, true);
		}
		while (len > 0)
		{
			size_t readlen = Decoder->read(buff, len);
			if (readlen == 0)
			{
				return false;
			}
			buff += readlen;
			len -= readlen;
			if (len > 0)
			{
				Decoder->seek(Loop_Start, false, true);
			}
		}
	}
	return true;
}