/*

   tapls - List for Spectrum TAP files

   Copyright (C) 2023  Ian Cowburn
   
   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; either version 2
   of the License, or (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

/* ---------------------------------------- MACROS
*/
#ifndef TRUE
#define TRUE 1
#endif

#ifndef FALSE
#define FALSE 0
#endif

/* ---------------------------------------- TYPES
*/
typedef unsigned char   Z80Byte;
typedef unsigned short  Z80Word;


/* ---------------------------------------- PRIVATE DATA
*/
const char *name;


/* ---------------------------------------- PRIVATE FUNCTIONS
*/
static Z80Byte GetTAPByte(FILE **tapfile)
{
    int ret=0;

    if (*tapfile)
    {
	ret = fgetc(*tapfile);

        if (ret == EOF)
        {
            ret = 0;
            fclose(*tapfile);
            *tapfile = NULL;
        }
    }

    return (Z80Byte)ret;
}


static Z80Word GetTAPLSBWord(FILE **tapfile)
{
    int c1,c2;

    c1 = GetTAPByte(tapfile);
    c2 = GetTAPByte(tapfile);

    return (Z80Word)(c1+(c2<<8));
}


static void TAPLoad(const char *path, FILE **tapfile)
{
    while(TRUE)
    {
        Z80Word blen;
        Z80Byte type,b,csum,tape_csum;

        b = 0;

        blen = GetTAPLSBWord(tapfile);
        type = GetTAPByte(tapfile);

        if (!*tapfile)
        {
            return;
        }

        csum = type;

        printf("%s: type = %u, block len = %u\n",
                    path, (unsigned)type, (unsigned)blen);

        /* Knock of block type
        */
        blen--;

        while(blen)
        {
            b=GetTAPByte(tapfile);
            csum^=b;
            blen--;
        }

        /* Get the checksum
        */
        if (blen)
        {
            tape_csum=GetTAPByte(tapfile);
            blen--;
        }
        else
        {
            tape_csum=b;
        }

        /* Check the checksum
        */
        printf("%s: checksums %s\n", path,
                                csum == tape_csum ? "match":"don't match");
    }
}


static void TapLS(const char *path)
{
    FILE *fp;

    fp = fopen(path, "rb");

    if (fp)
    {
        TAPLoad(path, &fp);
    }
    else
    {
        fprintf(stderr, "%s: failed to open '%s'\n", name, path);
    }
}


static void Usage(void)
{
    fprintf(stderr, "%s: usage %s [-d] [-h] tapefile ...\n", name, name);
}

/* ---------------------------------------- MAIN
*/
int main(int argc, char *argv[])
{
    int file_i;
    int f;
    int dump = FALSE;

    if (strrchr(argv[0], '/'))
    {
        name = strrchr(argv[0], '/') + 1;
    }
    else
    {
        name = argv[0];
    }

    file_i = 1;

    while(file_i < argc && argv[file_i][0] == '-')
    {
        switch(argv[file_i][1])
        {
            case 'd':
                dump = TRUE;
                break;
            case 'h':
                Usage();
                return EXIT_SUCCESS;
            default:
                fprintf(stderr, "%s: unknown switch '%c'\n",
                                                name, argv[file_i][1]);
                Usage();
                return EXIT_FAILURE;
        }

        file_i++;
    }

    if (file_i == argc)
    {
        Usage();
        return EXIT_FAILURE;
    }

    for(f = file_i; f < argc; f++)
    {
        TapLS(argv[f]);
    }

    return EXIT_SUCCESS;
}


/* END OF FILE */