#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "mloader.h"
#include "munitrk.h"

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


typedef struct MSAMPINFO{       // sample header as it appears in a module
	UBYTE samplename[22];
	UWORD length;
	UBYTE finetune;
	UBYTE volume;
	UWORD reppos;
	UWORD replen;
} MSAMPINFO;


typedef struct MODULEHEADER{                 // verbatim module header
	UBYTE      songname[20];                // the songname..
	MSAMPINFO  samples[15];                         // all sampleinfo
	UBYTE      songlength;                          // number of patterns used
	UBYTE      magic1;                                      // should be 127
	UBYTE      positions[128];                      // which pattern to play at pos
} MODULEHEADER;

typedef struct MODNOTE{
	UBYTE a,b,c,d;
} MODNOTE;


#define rword(p) ((((p)<<8)&0xff00) | (((p)>>8)&0x00ff))
#define cword(p) p=rword(p)

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

static MODULEHEADER *mh;        // raw as-is module header
static MODNOTE *patbuf;


BOOL M15_Test(void)
{
	int t;
	MODULEHEADER mh;

	fseek(modfp,0,SEEK_SET);
	if(!fread(&mh,sizeof(MODULEHEADER),1,modfp)) return 0;

	for(t=0;t<15;t++){

		// all finetunes should be zero
		if(mh.samples[t].finetune!=0) return 0;

		// all volumes should be <=64
		if(mh.samples[t].volume>64) return 0;
	}
	if(mh.magic1>127) return 0;    // and magic1 should be <128

	return 1;
}


BOOL M15_Init(void)
{
	patbuf=NULL;
	if(!(mh=(MODULEHEADER *)MyCalloc(1,sizeof(MODULEHEADER)))) return 0;
	return 1;
}


void M15_Cleanup(void)
{
	if(mh!=NULL) free(mh);
	if(patbuf!=NULL) free(patbuf);
}


/*

Old (amiga) noteinfo:

 _____byte 1_____   byte2_    _____byte 3_____   byte4_
/                \ /      \  /                \ /      \
0000          0000-00000000  0000          0000-00000000

Upper four    12 bits for    Lower four    Effect command.
bits of sam-  note period.   bits of sam-
ple number.                  ple number.


*/


UWORD M15_npertab[60]={

// -> Tuning 0

	1712,1616,1524,1440,1356,1280,1208,1140,1076,1016,960,906,
	856,808,762,720,678,640,604,570,538,508,480,453,
	428,404,381,360,339,320,302,285,269,254,240,226,
	214,202,190,180,170,160,151,143,135,127,120,113,
	107,101,95,90,85,80,75,71,67,63,60,56
};


void M15_ConvertNote(MODNOTE *n)
{
	UBYTE instrument,effect,effdat,note;
	UWORD period;

	/* extract the various information from the 4 bytes that
	   make up a single note */

	instrument=(n->a&0x10)|(n->c>>4);
	period=(((UWORD)n->a&0xf)<<8)+n->b;
	effect=n->c&0xf;
	effdat=n->d;

	// Convert the period to a note number

	note=0;
	if(period!=0){
		for(note=0;note<60;note++){
			if(period>=M15_npertab[note]) break;
		}
		note++;
		if(note==61) note=0;
	}

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

	if(note!=0){
		UniNote(note+23);
	}

	UniPTEffect(effect,effdat);
}



UBYTE *M15_ConvertTrack(MODNOTE *n)
{
	int t;

	UniReset();
	for(t=0;t<64;t++){
		M15_ConvertNote(n);
		UniNewline();
		n+=of.numchn;
	}
	return UniDup();
}



BOOL M15_LoadPatterns(void)
/*
	Loads all patterns of a modfile and converts them into the
	3 byte format.
*/
{
	int t,s,tracks=0;

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

	/* Allocate temporary buffer for loading
	   and converting the patterns */

	if(!(patbuf=(MODNOTE *)MyCalloc(64U*of.numchn,sizeof(MODNOTE)))) return 0;

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

		/* Load the pattern into the temp buffer
		   and convert it into the 3-byte format */

		if(fread(patbuf,64U*of.numchn*sizeof(MODNOTE),1,modfp)!=1){
			myerr=ERROR_LOADING_PATTERN;
			return 0;
		}

		for(s=0;s<of.numchn;s++){
			if(!(of.tracks[tracks++]=M15_ConvertTrack(patbuf+s))) return 0;
		}
	}

	return 1;
}



BOOL M15_Load(void)
{
	int t;
	INSTRUMENT *d;          // new sampleinfo structure
	SAMPLE *q;
	MSAMPINFO *s;           // old module sampleinfo

	rewind(modfp);

	// try to read module header

	if(!fread(mh,sizeof(MODULEHEADER),1,modfp)){
		myerr=ERROR_LOADING_HEADER;
		return 0;
	}

	// sample info to intel format

	for(t=0;t<15;t++){
		cword(mh->samples[t].length);
		cword(mh->samples[t].reppos);
		cword(mh->samples[t].replen);
	}

	/* set module variables */

	of.initspeed=6;
	of.inittempo=125;
	of.numchn=4;                                                    // get number of channels
	of.modtype=strdup("15-instrument");             // get ascii type of mod
	of.songname=DupStr(mh->songname,20);        // make a cstr of songname
	of.numpos=mh->songlength;                       // copy the songlength
	memcpy(of.positions,mh->positions,128);     // copy the position array

	/* Count the number of patterns */

	of.numpat=0;

	for(t=0;t<128;t++){             // <-- BUGFIX... have to check ALL positions
		if(of.positions[t] > of.numpat){
			of.numpat=of.positions[t];
		}
	}
	of.numpat++;
	of.numtrk=of.numpat*of.numchn;

	// Finally, init the sampleinfo structures

	of.numins=15;
	if(!AllocInstruments()) return 0;

	s=mh->samples;          // init source pointer
	d=of.instruments;       // init dest pointer

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

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

		q=d->samples;

		// convert the samplename

		d->insname=DupStr(s->samplename,22);

		/* init the sampleinfo variables and
		   convert the size pointers to longword format */

		q->c2spd=finetune[s->finetune&0xf];
		q->volume=s->volume;
		q->loopstart=s->reppos;
		q->loopend=q->loopstart+(s->replen<<1);
		q->length=s->length<<1;
		q->seekpos=0;

		q->flags=SF_SIGNED;
		if(s->replen>1) q->flags|=SF_LOOP;

		/* fix replen if repend>length */

		if(q->loopend>q->length) q->loopend=q->length;

		s++;    // point to next source sampleinfo
		d++;    // point to next destiny sampleinfo
	}

	if(!M15_LoadPatterns()) return 0;
	return 1;
}



LOADER m15load={
	NULL,
	"15-instrument module",
	"MOD-15 loader v0.1",
	M15_Init,
	M15_Test,
	M15_Load,
	M15_Cleanup
};