#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>

#define SIZE_REGS   48
#define SIZE_TFI    42

void cleanup(void);

typedef struct
{
    uint8_t version;
    uint8_t system;
    uint8_t instmode;
    uint8_t regs[SIZE_REGS];
} dmppatch;

typedef struct
{
    uint8_t regs[SIZE_TFI];
} tfipatch;

FILE *fin = NULL;
FILE *fout = NULL;

dmppatch *dmp;
tfipatch *tfi;

int main(int argc, char *argv[])
{
    int i, j, k;

    atexit(cleanup);

    if(argc < 3)
    {
        printf("%s in.dmp out.tfi\n",argv[0]);
        return 1;
    }

    dmp = malloc(sizeof(dmppatch));
    tfi = malloc(sizeof(tfipatch));

    if(!dmp || !tfi)
    {
        printf("Couldn't alloc mem\n");
        return 1;
    }

    memset(dmp, 0, sizeof(dmppatch));
    memset(tfi, 0, sizeof(tfipatch));

    fin = fopen(argv[1],"rb");

    if(!fin)
    {
        puts("Couldn't open file\n");
        return 1;
    }

    fread(&dmp->version, 1, 1, fin);
    fread(&dmp->system, 1, 1, fin);
    fread(&dmp->instmode, 1, 1, fin);

    if (dmp->version != 11) puts("Warn: not DMP version 11");
    if (dmp->system != 2) puts("Warn: not SYSTEM_GENESIS");

    if (dmp->instmode != 1)
    {
        puts("Err: Not a DMP FM instrument");
        return 1;
    }

    fread(dmp->regs, 1, SIZE_REGS, fin);
    fclose(fin);

    tfi->regs[0] = dmp->regs[2];
    tfi->regs[1] = dmp->regs[1];

    for(i = 0; i < 4; i++)
    {
        j = i * 10;
        k = i * 11;
        tfi->regs[2 + j] = dmp->regs[4 + k];
        tfi->regs[3 + j] = dmp->regs[12 + k];
        tfi->regs[4 + j] = dmp->regs[5 + k];
        tfi->regs[5 + j] = dmp->regs[11 + k];
        tfi->regs[6 + j] = dmp->regs[6 + k];
        tfi->regs[7 + j] = dmp->regs[7 + k];
        tfi->regs[8 + j] = dmp->regs[13 + k];
        tfi->regs[9 + j] = dmp->regs[9 + k];
        tfi->regs[10 + j] = dmp->regs[8 + k];
        tfi->regs[11 + j] = dmp->regs[14 + k] & 0x0F;
    }

    fout = fopen(argv[argc-1],"wb");

    if(!fout)
    {
            printf("Couldn't open %s for writing\n", argv[argc-1]);
            return 1;
    }

    fwrite(tfi, SIZE_TFI, 1, fout);

    return 0;
}

void cleanup(void)
{
    if (tfi) free(tfi);
    if (dmp) free(dmp);
    if (fin) fclose(fin);
    if (fout) fclose(fout);
}