//////////////////////////////////////////////////////////////////////////////
///   px8_d88
///   wrc 20190123
///   Read .d88 file and create epson px8 raw disk image
///
//////////////////////////////////////////////////////////////////////////////

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

#define DISK_SIDES                2
#define DISK_TRACKS              40
#define DISK_SECTORS             16
#define DISK_TOTAL_SECTORS      ( DISK_SECTORS * DISK_TRACKS * DISK_SIDES )
#define DISK_SECTOR_SIZE        256
#define DISK_TOTAL_BYTES        (DISK_TOTAL_SECTORS * DISK_SECTOR_SIZE)

#define FILE_HEADER_SIZE                0x2b0
#define FILE_SECTOR_HEADER_SIZE         16
#define FILE_SECTOR_SIZE                (DISK_SECTOR_SIZE + \
                                         FILE_SECTOR_HEADER_SIZE)

//////////////////////////////////////////////////////////////////////////////
//   .d88 file format
//
//  Header                      (0 to 2af)
//  000000:   Image name        ASCII text (xx chars, 0 term?)
//  000012:   Reserved
//  0000??:   Protect & type
//  00001c:   Size of file      !!! Differs from fjkraan (4 bytes, LE)
//  000022:   Track index
//
//  Sector Header               ( 16 bytes )
//      00:   Track             ( 0 to N-1)
//      01:   Side              ( 0 to N-1)
//      02:   Sector            ( 1 to N )
//      03:   Sector Size       ( 0 = 128, 1 = 256, 2 = 512, 3 = 1024)
//      04:   NSecLow           Number sectors in this track
//      05:   NSecHigh
//      06:   Density           ( 0 = double, 1 = high, ?? = single )
//      07:   Del ??
//      08:   Stat ??
//      09:   RESERVED
//      0A:   RESERVED
//      0B:   RESERVED
//      0C:   RESERVED
//      0D:   RESERVED
//      0E:   Data Size         ( 2 bytes, LE )
//      0F:   Data Size

//  0002b0:   First Sector      ( HDR: DATA )
//  0003c0:   Second Sector
//

// Keep track of which sectors were written
uint8_t sectorsWritten[ DISK_TOTAL_SECTORS ];
uint8_t sectorBuffer[ FILE_SECTOR_SIZE ];  // Hold an incoming sector
uint8_t diskImage[ DISK_TOTAL_BYTES ];     // Image of entire disk

FILE* infile;
FILE* outfile;

int readSector(int s, uint8_t* buff);
int writeSector(uint8_t* buff, uint8_t* img);

int main(int argc, char **argv)
{
  int rtn = 0;
  printf("argc is %d \n", argc);
  if(argc != 3)
  {
    printf("usage:   px8_d88 infile.d88 outfile.img \n\n");
    exit(1);
  }

  infile = fopen(argv[1], "r");
  outfile = fopen(argv[2], "w");
  if(infile == NULL)
  {
    printf("Could not open input file \n");
    exit(1);
  }
  if(outfile == NULL)
  {
    printf("Could not open outpuf file \n");
    exit(1);
  }

  for(int i = 0; i < DISK_TOTAL_BYTES; i++)
  {
    diskImage[i] = 0xe5;      // clear the image
  }

  for(int sec = 0; sec < DISK_TOTAL_SECTORS; sec++)
  {
    readSector(sec, sectorBuffer);
    writeSector(sectorBuffer, diskImage);
  }

  fclose(infile);
  
  printf("Following sectors written more or less than once! \n");
  for(int sec = 0; sec < DISK_TOTAL_SECTORS; sec++)
  {
    if(sectorsWritten[sec] != 1)
    {
      printf("%4d    %2d  \n", sec, sectorsWritten[sec]);
    }

  }

  printf("Writing image file %s \n", argv[2]);
  for(int b = 0; b < DISK_TOTAL_BYTES; b++)
  {
    fputc(diskImage[b], outfile);
  }

  fclose(outfile);

  return rtn;
}




int readSector(int s, uint8_t* buff)
{
  int rtn = 0;
  fseek(infile, FILE_HEADER_SIZE + FILE_SECTOR_SIZE * s, SEEK_SET);
  fread(sectorBuffer, FILE_SECTOR_SIZE, 1, infile);


  return rtn;
}

int writeSector(uint8_t* buff, uint8_t* img)
{
  int track = buff[0];
  int side = buff[1];
  int sector = buff[2] - 1;  // sector #'s start at 1
  // assume sector size of 256 bytes
  int thisSector = track * DISK_SIDES * DISK_SECTORS;
  thisSector += side * DISK_SECTORS;
  thisSector += sector;
  printf("Writing sector %d\n", thisSector);
  sectorsWritten[thisSector]++;
  int offset = thisSector * DISK_SECTOR_SIZE;
  for(int i = 0; i < DISK_SECTOR_SIZE; i++)
  {
    diskImage[ offset + i ] = sectorBuffer[ i + FILE_SECTOR_HEADER_SIZE ];
  }

  return 0;
}