/*
 * This source code is public domain.
 *
 * Authors: Olivier Lapicque <olivierl@jps.net>,
 *          Adam Goode       <adam@evdebs.org> (endian and char fixes for PPC)
*/

#include "libmodplug.h"
#include "tables.h"

//////////////////////////////////////////////////////////
// ProTracker / NoiseTracker MOD/NST file support

void CSoundFile_ConvertModCommand(CSoundFile *_this, MODCOMMAND *m)
//-----------------------------------------------------
{
	UINT command = m->command, param = m->param;

	switch(command)
	{
	case 0x00:	if (param) command = CMD_ARPEGGIO; break;
	case 0x01:	command = CMD_PORTAMENTOUP; break;
	case 0x02:	command = CMD_PORTAMENTODOWN; break;
	case 0x03:	command = CMD_TONEPORTAMENTO; break;
	case 0x04:	command = CMD_VIBRATO; break;
	case 0x05:	command = CMD_TONEPORTAVOL; if (param & 0xF0) param &= 0xF0; break;
	case 0x06:	command = CMD_VIBRATOVOL; if (param & 0xF0) param &= 0xF0; break;
	case 0x07:	command = CMD_TREMOLO; break;
	case 0x08:	command = CMD_PANNING8; break;
	case 0x09:	command = CMD_OFFSET; break;
	case 0x0A:	command = CMD_VOLUMESLIDE; if (param & 0xF0) param &= 0xF0; break;
	case 0x0B:	command = CMD_POSITIONJUMP; break;
	case 0x0C:	command = CMD_VOLUME; break;
	case 0x0D:	command = CMD_PATTERNBREAK; param = ((param >> 4) * 10) + (param & 0x0F); break;
	case 0x0E:	command = CMD_MODCMDEX; break;
	case 0x0F:	command = (param <= (UINT)((_this->m_nType & (MOD_TYPE_XM|MOD_TYPE_MT2)) ? 0x1F : 0x20)) ? CMD_SPEED : CMD_TEMPO;
				if ((param == 0xFF) && (_this->m_nSamples == 15)) command = 0; break;
	// Extension for XM extended effects
	case 'G' - 55:	command = CMD_GLOBALVOLUME; break;
	case 'H' - 55:	command = CMD_GLOBALVOLSLIDE; if (param & 0xF0) param &= 0xF0; break;
	case 'K' - 55:	command = CMD_KEYOFF; break;
	case 'L' - 55:	command = CMD_SETENVPOSITION; break;
	case 'M' - 55:	command = CMD_CHANNELVOLUME; break;
	case 'N' - 55:	command = CMD_CHANNELVOLSLIDE; break;
	case 'P' - 55:	command = CMD_PANNINGSLIDE; if (param & 0xF0) param &= 0xF0; break;
	case 'R' - 55:	command = CMD_RETRIG; break;
	case 'T' - 55:	command = CMD_TREMOR; break;
	case 'X' - 55:	command = CMD_XFINEPORTAUPDOWN;	break;
	case 'Y' - 55:	command = CMD_PANBRELLO; break;
	case 'Z' - 55:	command = CMD_MIDI;	break;
	default:	command = 0;
	}
	m->command = command;
	m->param = param;
}


#pragma pack(1)

typedef struct _MODSAMPLE
{
	CHAR name[22];
	WORD length;
	BYTE finetune;
	BYTE volume;
	WORD loopstart;
	WORD looplen;
} MODSAMPLE, *PMODSAMPLE;

typedef struct _MODMAGIC
{
	BYTE nOrders;
	BYTE nRestartPos;
	BYTE Orders[128];
        char Magic[4];          // changed from CHAR
} MODMAGIC, *PMODMAGIC;

#pragma pack()

static BOOL IsMagic(LPCSTR s1, LPCSTR s2)
{
	return ((*(DWORD *)s1) == (*(DWORD *)s2)) ? TRUE : FALSE;
}


BOOL CSoundFile_ReadMod(CSoundFile *_this, const BYTE *lpStream, DWORD dwMemLength)
//---------------------------------------------------------------
{
    char s[1024];          // changed from CHAR
	DWORD dwMemPos, dwTotalSampleLen;
	PMODMAGIC pMagic;
	UINT nErr;

	if ((!lpStream) || (dwMemLength < 0x600)) return FALSE;
	dwMemPos = 20;
	_this->m_nSamples = 31;
	_this->m_nChannels = 4;
	pMagic = (PMODMAGIC)(lpStream+dwMemPos+sizeof(MODSAMPLE)*31);
	// Check Mod Magic
	SDL_memcpy(s, pMagic->Magic, 4);
	if ((IsMagic(s, "M.K.")) || (IsMagic(s, "M!K!"))
	 || (IsMagic(s, "M&K!")) || (IsMagic(s, "N.T."))) _this->m_nChannels = 4; else
	if ((IsMagic(s, "CD81")) || (IsMagic(s, "OKTA"))) _this->m_nChannels = 8; else
	if ((s[0]=='F') && (s[1]=='L') && (s[2]=='T') && (s[3]>='4') && (s[3]<='9')) _this->m_nChannels = s[3] - '0'; else
	if ((s[0]>='2') && (s[0]<='9') && (s[1]=='C') && (s[2]=='H') && (s[3]=='N')) _this->m_nChannels = s[0] - '0'; else
	if ((s[0]=='1') && (s[1]>='0') && (s[1]<='9') && (s[2]=='C') && (s[3]=='H')) _this->m_nChannels = s[1] - '0' + 10; else
	if ((s[0]=='2') && (s[1]>='0') && (s[1]<='9') && (s[2]=='C') && (s[3]=='H')) _this->m_nChannels = s[1] - '0' + 20; else
	if ((s[0]=='3') && (s[1]>='0') && (s[1]<='2') && (s[2]=='C') && (s[3]=='H')) _this->m_nChannels = s[1] - '0' + 30; else
	if ((s[0]=='T') && (s[1]=='D') && (s[2]=='Z') && (s[3]>='4') && (s[3]<='9')) _this->m_nChannels = s[3] - '0'; else
	if (IsMagic(s,"16CN")) _this->m_nChannels = 16; else
	if (IsMagic(s,"32CN")) _this->m_nChannels = 32; else _this->m_nSamples = 15;
	// Load Samples
	nErr = 0;
	dwTotalSampleLen = 0;
	for	(UINT i=1; i<=_this->m_nSamples; i++)
	{
		PMODSAMPLE pms = (PMODSAMPLE)(lpStream+dwMemPos);
		MODINSTRUMENT *psmp = &_this->Ins[i];
		UINT loopstart, looplen;

		psmp->uFlags = 0;
		psmp->nLength = bswapBE16(pms->length)*2;
		dwTotalSampleLen += psmp->nLength;
		psmp->nFineTune = MOD2XMFineTune(pms->finetune & 0x0F);
		psmp->nVolume = 4*pms->volume;
		if (psmp->nVolume > 256) { psmp->nVolume = 256; nErr++; }
		psmp->nGlobalVol = 64;
		psmp->nPan = 128;
		loopstart = bswapBE16(pms->loopstart)*2;
		looplen = bswapBE16(pms->looplen)*2;
		// Fix loops
		if ((looplen > 2) && (loopstart+looplen > psmp->nLength)
		 && (loopstart/2+looplen <= psmp->nLength))
		{
			loopstart /= 2;
		}
		psmp->nLoopStart = loopstart;
		psmp->nLoopEnd = loopstart + looplen;
		if (psmp->nLength < 4) psmp->nLength = 0;
		if (psmp->nLength)
		{
			if (psmp->nLoopStart >= psmp->nLength) { psmp->nLoopStart = psmp->nLength-1; }
			if (psmp->nLoopEnd > psmp->nLength) { psmp->nLoopEnd = psmp->nLength; }

			if ((psmp->nLoopStart > psmp->nLoopEnd) || (psmp->nLoopEnd <= 8)
			 || (psmp->nLoopEnd - psmp->nLoopStart <= 4))
			{
				psmp->nLoopStart = 0;
				psmp->nLoopEnd = 0;
			}
			if (psmp->nLoopEnd > psmp->nLoopStart)
			{
				psmp->uFlags |= CHN_LOOP;
			}
		}
		dwMemPos += sizeof(MODSAMPLE);
	}
	if ((_this->m_nSamples == 15) && (dwTotalSampleLen > dwMemLength * 4)) return FALSE;
	pMagic = (PMODMAGIC)(lpStream+dwMemPos);
	dwMemPos += sizeof(MODMAGIC);
	if (_this->m_nSamples == 15) dwMemPos -= 4;
	SDL_memset(_this->Order, 0,sizeof(_this->Order));
	SDL_memcpy(_this->Order, pMagic->Orders, 128);

	UINT nbp, nbpbuggy, nbpbuggy2, norders;

	norders = pMagic->nOrders;
	if ((!norders) || (norders > 0x80))
	{
		norders = 0x80;
		while ((norders > 1) && (!_this->Order[norders-1])) norders--;
	}
	nbpbuggy = 0;
	nbpbuggy2 = 0;
	nbp = 0;
	for (UINT iord=0; iord<128; iord++)
	{
		UINT i = _this->Order[iord];
		if ((i < 0x80) && (nbp <= i))
		{
			nbp = i+1;
			if (iord<norders) nbpbuggy = nbp;
		}
		if (i >= nbpbuggy2) nbpbuggy2 = i+1;
	}
	for (UINT iend=norders; iend<MAX_ORDERS; iend++) _this->Order[iend] = 0xFF;
	norders--;
	_this->m_nRestartPos = pMagic->nRestartPos;
	if (_this->m_nRestartPos >= 0x78) _this->m_nRestartPos = 0;
	if (_this->m_nRestartPos + 1 >= (UINT)norders) _this->m_nRestartPos = 0;
	if (!nbp) return FALSE;
	DWORD dwWowTest = dwTotalSampleLen+dwMemPos;
	if ((IsMagic(pMagic->Magic, "M.K.")) && (dwWowTest + nbp*8*256 == dwMemLength)) _this->m_nChannels = 8;
	if ((nbp != nbpbuggy) && (dwWowTest + nbp*_this->m_nChannels*256 != dwMemLength))
	{
		if (dwWowTest + nbpbuggy*_this->m_nChannels*256 == dwMemLength) nbp = nbpbuggy;
		else nErr += 8;
	} else
	if ((nbpbuggy2 > nbp) && (dwWowTest + nbpbuggy2*_this->m_nChannels*256 == dwMemLength))
	{
		nbp = nbpbuggy2;
	}
	if ((dwWowTest < 0x600) || (dwWowTest > dwMemLength)) nErr += 8;
	if ((_this->m_nSamples == 15) && (nErr >= 16)) return FALSE;
	// Default settings	
	_this->m_nType = MOD_TYPE_MOD;
	_this->m_nDefaultSpeed = 6;
	_this->m_nDefaultTempo = 125;
	_this->m_nMinPeriod = 14 << 2;
	_this->m_nMaxPeriod = 3424 << 2;
	// Setting channels pan
	for (UINT ich=0; ich<_this->m_nChannels; ich++)
	{
		_this->ChnSettings[ich].nVolume = 64;
		if (_this->gdwSoundSetup & SNDMIX_MAXDEFAULTPAN)
			_this->ChnSettings[ich].nPan = (((ich&3)==1) || ((ich&3)==2)) ? 256 : 0;
		else
			_this->ChnSettings[ich].nPan = (((ich&3)==1) || ((ich&3)==2)) ? 0xC0 : 0x40;
	}
	// Reading channels
	for (UINT ipat=0; ipat<nbp; ipat++)
	{
		if (ipat < MAX_PATTERNS)
		{
			if ((_this->Patterns[ipat] = CSoundFile_AllocatePattern(64, _this->m_nChannels)) == NULL) break;
			_this->PatternSize[ipat] = 64;
			if (dwMemPos + _this->m_nChannels*256 >= dwMemLength) break;
			MODCOMMAND *m = _this->Patterns[ipat];
			LPCBYTE p = lpStream + dwMemPos;
			for (UINT j=_this->m_nChannels*64; j; m++,p+=4,j--)
			{
				BYTE A0=p[0], A1=p[1], A2=p[2], A3=p[3];
				UINT n = ((((UINT)A0 & 0x0F) << 8) | (A1));
				if ((n) && (n != 0xFFF)) m->note = CSoundFile_GetNoteFromPeriod(_this, n << 2);
				m->instr = ((UINT)A2 >> 4) | (A0 & 0x10);
				m->command = A2 & 0x0F;
				m->param = A3;
				if ((m->command) || (m->param)) CSoundFile_ConvertModCommand(_this, m);
			}
		}
		dwMemPos += _this->m_nChannels*256;
	}
	// Reading instruments
	DWORD dwErrCheck = 0;
	for (UINT ismp=1; ismp<=_this->m_nSamples; ismp++) if (_this->Ins[ismp].nLength)
	{
		LPSTR p = (LPSTR)(lpStream+dwMemPos);
		UINT flags = 0;
		if (dwMemPos + 5 >= dwMemLength) break;
		if (!SDL_strncasecmp(p, "ADPCM", 5))
		{
			flags = 3;
			p += 5;
			dwMemPos += 5;
		}
		DWORD dwSize = CSoundFile_ReadSample(_this, &_this->Ins[ismp], flags, p, dwMemLength - dwMemPos);
		if (dwSize)
		{
			dwMemPos += dwSize;
			dwErrCheck++;
		}
	}
#ifdef MODPLUG_TRACKER
	return TRUE;
#else
	return (dwErrCheck) ? TRUE : FALSE;
#endif
}