/*
 * Load_far.cpp
 * ------------
 * Purpose: Farandole (FAR) module loader
 * Notes  : (currently none)
 * Authors: OpenMPT Devs (partly inspired by Storlek's FAR loader from Schism Tracker)
 * The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
 */


#include "stdafx.h"
#include "Loaders.h"


OPENMPT_NAMESPACE_BEGIN

// FAR File Header
struct FARFileHeader
{
	uint8le  magic[4];
	char     songName[40];
	uint8le  eof[3];
	uint16le headerLength;
	uint8le  version;
	uint8le  onOff[16];
	uint8le  editingState[9];	// Stuff we don't care about
	uint8le  defaultSpeed;
	uint8le  chnPanning[16];
	uint8le  patternState[4];	// More stuff we don't care about
	uint16le messageLength;
};

MPT_BINARY_STRUCT(FARFileHeader, 98)


struct FAROrderHeader
{
	uint8le  orders[256];
	uint8le  numPatterns;	// supposed to be "number of patterns stored in the file"; apparently that's wrong
	uint8le  numOrders;
	uint8le  restartPos;
	uint16le patternSize[256];
};

MPT_BINARY_STRUCT(FAROrderHeader, 771)


// FAR Sample header
struct FARSampleHeader
{
	// Sample flags
	enum SampleFlags
	{
		smp16Bit	= 0x01,
		smpLoop		= 0x08,
	};

	char     name[32];
	uint32le length;
	uint8le  finetune;
	uint8le  volume;
	uint32le loopStart;
	uint32le loopEnd;
	uint8le  type;
	uint8le  loop;

	// Convert sample header to OpenMPT's internal format.
	void ConvertToMPT(ModSample &mptSmp) const
	{
		mptSmp.Initialize();

		mptSmp.nLength = length;
		mptSmp.nLoopStart = loopStart;
		mptSmp.nLoopEnd = loopEnd;
		mptSmp.nC5Speed = 8363 * 2;
		mptSmp.nVolume = volume * 16;

		if(type & smp16Bit)
		{
			mptSmp.nLength /= 2;
			mptSmp.nLoopStart /= 2;
			mptSmp.nLoopEnd /= 2;
		}

		if((loop & 8) && mptSmp.nLoopEnd > mptSmp.nLoopStart)
		{
			mptSmp.uFlags.set(CHN_LOOP);
		}
	}

	// Retrieve the internal sample format flags for this sample.
	SampleIO GetSampleFormat() const
	{
		return SampleIO(
			(type & smp16Bit) ? SampleIO::_16bit : SampleIO::_8bit,
			SampleIO::mono,
			SampleIO::littleEndian,
			SampleIO::signedPCM);
	}
};

MPT_BINARY_STRUCT(FARSampleHeader, 48)


static bool ValidateHeader(const FARFileHeader &fileHeader)
{
	if(std::memcmp(fileHeader.magic, "FAR\xFE", 4) != 0
		|| std::memcmp(fileHeader.eof, "\x0D\x0A\x1A", 3)
		)
	{
		return false;
	}
	if(fileHeader.headerLength < sizeof(FARFileHeader))
	{
		return false;
	}
	return true;
}


static uint64 GetHeaderMinimumAdditionalSize(const FARFileHeader &fileHeader)
{
	return fileHeader.headerLength - sizeof(FARFileHeader);
}


CSoundFile::ProbeResult CSoundFile::ProbeFileHeaderFAR(MemoryFileReader file, const uint64 *pfilesize)
{
	FARFileHeader fileHeader;
	if(!file.ReadStruct(fileHeader))
	{
		return ProbeWantMoreData;
	}
	if(!ValidateHeader(fileHeader))
	{
		return ProbeFailure;
	}
	return ProbeAdditionalSize(file, pfilesize, GetHeaderMinimumAdditionalSize(fileHeader));
}


bool CSoundFile::ReadFAR(FileReader &file, ModLoadingFlags loadFlags)
{
	file.Rewind();

	FARFileHeader fileHeader;
	if(!file.ReadStruct(fileHeader))
	{
		return false;
	}
	if(!ValidateHeader(fileHeader))
	{
		return false;
	}
	if(!file.CanRead(mpt::saturate_cast<FileReader::off_t>(GetHeaderMinimumAdditionalSize(fileHeader))))
	{
		return false;
	}
	if(loadFlags == onlyVerifyHeader)
	{
		return true;
	}

	// Globals
	InitializeGlobals(MOD_TYPE_FAR);
	m_nChannels = 16;
	m_nSamplePreAmp = 32;
	m_nDefaultSpeed = fileHeader.defaultSpeed;
	m_nDefaultTempo.Set(80);
	m_nDefaultGlobalVolume = MAX_GLOBAL_VOLUME;
	m_SongFlags = SONG_LINEARSLIDES;
	m_playBehaviour.set(kPeriodsAreHertz);

	m_modFormat.formatName = U_("Farandole Composer");
	m_modFormat.type = U_("far");
	m_modFormat.charset = mpt::Charset::CP437;

	m_songName = mpt::String::ReadBuf(mpt::String::maybeNullTerminated, fileHeader.songName);

	// Read channel settings
	for(CHANNELINDEX chn = 0; chn < 16; chn++)
	{
		ChnSettings[chn].Reset();
		ChnSettings[chn].dwFlags = fileHeader.onOff[chn] ? ChannelFlags(0) : CHN_MUTE;
		ChnSettings[chn].nPan = ((fileHeader.chnPanning[chn] & 0x0F) << 4) + 8;
	}

	// Read song message
	if(fileHeader.messageLength != 0)
	{
		m_songMessage.ReadFixedLineLength(file, fileHeader.messageLength, 132, 0);	// 132 characters per line... wow. :)
	}

	// Read orders
	FAROrderHeader orderHeader;
	if(!file.ReadStruct(orderHeader))
	{
		return false;
	}
	ReadOrderFromArray(Order(), orderHeader.orders, orderHeader.numOrders, 0xFF, 0xFE);
	Order().SetRestartPos(orderHeader.restartPos);

	file.Seek(fileHeader.headerLength);
	
	// Pattern effect LUT
	static constexpr EffectCommand farEffects[] =
	{
		CMD_NONE,
		CMD_PORTAMENTOUP,
		CMD_PORTAMENTODOWN,
		CMD_TONEPORTAMENTO,
		CMD_RETRIG,
		CMD_VIBRATO,		// depth
		CMD_VIBRATO,		// speed
		CMD_VOLUMESLIDE,	// up
		CMD_VOLUMESLIDE,	// down
		CMD_VIBRATO,		// sustained (?)
		CMD_NONE,			// actually slide-to-volume
		CMD_S3MCMDEX,		// panning
		CMD_S3MCMDEX,		// note offset => note delay?
		CMD_NONE,			// fine tempo down
		CMD_NONE,			// fine tempo up
		CMD_SPEED,
	};
	
	// Read patterns
	for(PATTERNINDEX pat = 0; pat < 256; pat++)
	{
		if(!orderHeader.patternSize[pat])
		{
			continue;
		}

		FileReader patternChunk = file.ReadChunk(orderHeader.patternSize[pat]);

		// Calculate pattern length in rows (every event is 4 bytes, and we have 16 channels)
		ROWINDEX numRows = (orderHeader.patternSize[pat] - 2) / (16 * 4);
		if(!(loadFlags & loadPatternData) || !Patterns.Insert(pat, numRows))
		{
			continue;
		}

		// Read break row and unused value (used to be pattern tempo)
		ROWINDEX breakRow = patternChunk.ReadUint8();
		patternChunk.Skip(1);
		if(breakRow > 0 && breakRow < numRows - 2)
		{
			breakRow++;
		} else
		{
			breakRow = ROWINDEX_INVALID;
		}

		// Read pattern data
		for(ROWINDEX row = 0; row < numRows; row++)
		{
			for(ModCommand &m : Patterns[pat].GetRow(row))
			{
				const auto [note, instr, volume, effect] = patternChunk.ReadArray<uint8, 4>();

				if(note > 0 && note <= 72)
				{
					m.note = note + 35 + NOTE_MIN;
					m.instr = instr + 1;
				}

				if(volume > 0 && volume <= 16)
				{
					m.volcmd = VOLCMD_VOLUME;
					m.vol = (volume - 1u) * 64u / 15u;
				}
				
				m.param = effect & 0x0F;

				switch(effect >> 4)
				{
				case 0x01:
				case 0x02:
					m.param |= 0xF0;
					break;
				case 0x03:	// Porta to note (TODO: Parameter is number of rows the portamento should take)
					m.param <<= 2;
					break;
				case 0x04:	// Retrig
					m.param = 6 / (1 + (m.param & 0xf)) + 1; // ugh?
					break;
				case 0x06:	// Vibrato speed
				case 0x07:	// Volume slide up
					m.param *= 8;
					break;
				case 0x0A:	// Volume-portamento (what!)
					m.volcmd = VOLCMD_VOLUME;
					m.vol = (m.param << 2) + 4;
					break;
				case 0x0B:	// Panning
					m.param |= 0x80;
					break;
				case 0x0C:	// Note offset
					m.param = 6 / (1 + m.param) + 1;
					m.param |= 0x0D;
				}
				m.command = farEffects[effect >> 4];
			}
		}

		Patterns[pat].WriteEffect(EffectWriter(CMD_PATTERNBREAK, 0).Row(breakRow).RetryNextRow());
	}
	
	if(!(loadFlags & loadSampleData))
	{
		return true;
	}

	// Read samples
	uint8 sampleMap[8];	// Sample usage bitset
	file.ReadArray(sampleMap);

	for(SAMPLEINDEX smp = 0; smp < 64; smp++)
	{
		if(!(sampleMap[smp >> 3] & (1 << (smp & 7))))
		{
			continue;
		}

		FARSampleHeader sampleHeader;
		if(!file.ReadStruct(sampleHeader))
		{
			return true;
		}

		m_nSamples = smp + 1;
		ModSample &sample = Samples[m_nSamples];
		m_szNames[m_nSamples] = mpt::String::ReadBuf(mpt::String::nullTerminated, sampleHeader.name);
		sampleHeader.ConvertToMPT(sample);
		sampleHeader.GetSampleFormat().ReadSample(sample, file);
	}
	return true;
}


OPENMPT_NAMESPACE_END
