/*

Name:
LOAD_MTM.C

Description:
MTM module loader

Portability:
All systems - all compilers (hopefully)

*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "mikmod.h"

/**************************************************************************
**************************************************************************/


typedef struct MTMSAMPLE{
	char  samplename[22];
	ULONG length;
	ULONG reppos;
	ULONG repend;
	UBYTE finetune;
	UBYTE volume;
	UBYTE attribute;
} MTMSAMPLE;



typedef struct MTMHEADER{
	UBYTE id[3];                            /* MTM file marker */
	UBYTE version;                          /* upper major, lower nibble minor version number */
	char  songname[20];                     /* ASCIIZ songname */
	UWORD numtracks;                        /* number of tracks saved */
	UBYTE lastpattern;                      /* last pattern number saved */
	UBYTE lastorder;                        /* last order number to play (songlength-1) */
	UWORD commentsize;                      /* length of comment field */
	UBYTE numsamples;                       /* number of samples saved */
	UBYTE attribute;                        /* attribute byte (unused) */
	UBYTE beatspertrack;            /* */
	UBYTE numchannels;                      /* number of channels used */
	UBYTE panpos[32];                       /* voice pan positions */
} MTMHEADER;


typedef struct MTMNOTE{
	UBYTE a,b,c;
} MTMNOTE;


/**************************************************************************
**************************************************************************/



static MTMHEADER *mh;
MTMNOTE *mtmtrk;
UWORD pat[32];

char MTM_Version[]="MTM";



BOOL MTM_Test(void)
{
	char id[3];
	if(!fread(id,3,1,modfp)) return 0;
	if(!memcmp(id,"MTM",3)) return 1;
	return 0;
}


BOOL MTM_Init(void)
{
	mtmtrk=NULL;
	mh=NULL;

	if(!(mtmtrk=MyCalloc(64,sizeof(MTMNOTE)))) return 0;
	if(!(mh=MyCalloc(1,sizeof(MTMHEADER)))) return 0;

	return 1;
}


void MTM_Cleanup(void)
{
	if(mtmtrk!=NULL) free(mtmtrk);
	if(mh!=NULL) free(mh);
}



UBYTE *MTM_Convert(void)
{
	int t;
	UBYTE a,b,c,inst,note,eff,dat;

	UniReset();
	for(t=0;t<64;t++){

		a=mtmtrk[t].a;
		b=mtmtrk[t].b;
		c=mtmtrk[t].c;

		inst=((a&0x3)<<4)|(b>>4);
		note=a>>2;

		eff=b&0xf;
		dat=c;


		if(inst!=0){
			UniInstrument(inst-1);
		}

		if(note!=0){
			UniNote(note+24);
		}

		/* mtm bug bugfix: when the effect is volslide,
		   slide-up _always_ overrides slide-dn. */

		if(eff==0xa && dat&0xf0) dat&=0xf0;

		UniPTEffect(eff,dat);
		UniNewline();
	}
	return UniDup();
}


BOOL MTM_Load(void)
{
	MTMSAMPLE s;
	INSTRUMENT *d;
	SAMPLE *q;

	int t,u;

	/* try to read module header */

	_mm_read_str(mh->id,3,modfp);
	mh->version		=_mm_read_UBYTE(modfp);
	_mm_read_str(mh->songname,20,modfp);
	mh->numtracks	=_mm_read_I_UWORD(modfp);
	mh->lastpattern	=_mm_read_UBYTE(modfp);
	mh->lastorder	=_mm_read_UBYTE(modfp);
	mh->commentsize	=_mm_read_I_UWORD(modfp);
	mh->numsamples	=_mm_read_UBYTE(modfp);
	mh->attribute	=_mm_read_UBYTE(modfp);
	mh->beatspertrack=_mm_read_UBYTE(modfp);
	mh->numchannels	=_mm_read_UBYTE(modfp);
	_mm_read_UBYTES(mh->panpos,32,modfp);

	if(feof(modfp)){
		myerr=ERROR_LOADING_HEADER;
		return 0;
	}

	/* set module variables */

	of.initspeed=6;
	of.inittempo=125;
	of.modtype=strdup(MTM_Version);
	of.numchn=mh->numchannels;
	of.numtrk=mh->numtracks+1;                              /* get number of channels */
	of.songname=DupStr(mh->songname,20);    /* make a cstr of songname */
	of.numpos=mh->lastorder+1;              /* copy the songlength */
	of.numpat=mh->lastpattern+1;
	for(t=0;t<32;t++) of.panning[t]=mh->panpos[t]<<4;

	of.numins=mh->numsamples;
	if(!AllocInstruments()) return 0;

	d=of.instruments;

	for(t=0;t<of.numins;t++){

		d->numsmp=1;
		if(!AllocSamples(d)) return 0;
		q=d->samples;

		/* try to read sample info */

		_mm_read_str(s.samplename,22,modfp);
		s.length	=_mm_read_I_ULONG(modfp);
		s.reppos	=_mm_read_I_ULONG(modfp);
		s.repend	=_mm_read_I_ULONG(modfp);
		s.finetune	=_mm_read_UBYTE(modfp);
		s.volume	=_mm_read_UBYTE(modfp);
		s.attribute	=_mm_read_UBYTE(modfp);

		if(feof(modfp)){
			myerr=ERROR_LOADING_SAMPLEINFO;
			return 0;
		}

		d->insname=DupStr(s.samplename,22);
		q->seekpos=0;
		q->c2spd=finetune[s.finetune];
		q->length=s.length;
		q->loopstart=s.reppos;
		q->loopend=s.repend;
		q->volume=s.volume;

		q->flags=0;

		if(s.repend-s.reppos>2) q->flags|=SF_LOOP;      /* <- 1.00 bugfix */

		if(s.attribute&1){

			/* If the sample is 16-bits, convert the length
			   and replen byte-values into sample-values */

			q->flags|=SF_16BITS;
			q->length>>=1;
			q->loopstart>>=1;
			q->loopend>>=1;
		}

		d++;
	}

	_mm_read_UBYTES(of.positions,128,modfp);

	if(feof(modfp)){
		myerr=ERROR_LOADING_HEADER;
		return 0;
	}

	if(!AllocTracks()) return 0;
	if(!AllocPatterns()) return 0;

	of.tracks[0]=MTM_Convert();             /* track 0 is empty */

	for(t=1;t<of.numtrk;t++){
		int s;

		for(s=0;s<64;s++){
			mtmtrk[s].a=_mm_read_UBYTE(modfp);
			mtmtrk[s].b=_mm_read_UBYTE(modfp);
			mtmtrk[s].c=_mm_read_UBYTE(modfp);
		}

		if(feof(modfp)){
			myerr="Error loading track";
			return 0;
		}

		if(!(of.tracks[t]=MTM_Convert())) return 0;
	}

	for(t=0;t<of.numpat;t++){

		_mm_read_I_UWORDS(pat,32,modfp);

		for(u=0;u<of.numchn;u++){
			of.patterns[((long)t*of.numchn)+u]=pat[u];
		}
	}

	/* read comment field */

	if(!ReadComment(mh->commentsize)) return 0;

	return 1;
}



LOADER load_mtm={
	NULL,
	"MTM",
	"Portable MTM loader v0.1",
	MTM_Init,
	MTM_Test,
	MTM_Load,
	MTM_Cleanup
};