/*********************************************
****        DCD fix for VMD V1.0          ****
****   Fix DCD files to be VMD readable   ****
****     (c) 2010, Alessandro Pedretti    ****
*********************************************/


#define VGVLL
#include <vega.h>
#include <stdio.h>
#include <string.h>

/**** Labels ****/

char *   MsgDone            = "DCD file fixed";
char *   MsgError           = "ERROR";
char *   MsgNotNeeded       = "The is already in the right format";
char *   MsgOdFilter        = "DCD file (*.dcd)|*.dcd";
char *   MsgOdTitle         = "Open the DCD file ...";

char *   MsgErrFormat       = "The file isn't in DCD format";
char *   MsgErrNotFound     = "Input file not found";
char *   MsgErrRead         = "Can't read the DCD file";
char *   MsgErrWrite        = "Can't write the DCD file";


/**** Prototypes ****/

void         Error(const char *Err);


/**** Main code ****/

int VllMain(VGP_VEGAINFO *VegaInfo)
{
  char        Buf[256];
  FILE *      InFH;
  VG_LONG     LineNum, SwapEndian;


  /**** Translate the labels ****/

  VegaCmd("Get CurLang");
  if (!strcmp(VegaInfo -> Result, "italiano")) {
    MsgDone            = "File DCD corretto";
    MsgError           = "ERRORE";
    MsgNotNeeded       = "Il file è già nel formato corretto";
    MsgOdFilter        = "File DCD (*.dcd)|*.dcd";
    MsgOdTitle         = "Apri il file DCD ...";

    MsgErrFormat       = "Il file non è in formato DCD";
    MsgErrNotFound     = "File d'input non trovato";
    MsgErrRead         = "Impossibile leggere il file DCD";
    MsgErrWrite        = "Impossibile scrivere il file DCD";
  }

  /**** Show the file requester ****/

  VegaCmdEx("OpenDlg \"%s\" \"\" \"%s\" 1", MsgOdTitle, MsgOdFilter);
  if (!*VegaInfo -> Result) return 0;

  /**** Open the input file ****/

  if ((InFH = fopen(VegaInfo -> Result, "rb+")) == NULL) {
    Error(MsgErrNotFound);
    return 0;
  }

  /**** File format detection ****/

  if ((fread(Buf, 8, 1, InFH) != 1) ||
      (!strncmp(Buf + 4, "COORD", 4))) {
    Error(MsgErrFormat);
    goto CloseAll;
  }

  /**** Check the endian ****/

  SwapEndian = (Buf[3] == 84);

  /**** Check if the fix is required ****/

  fseek(InFH, 0x60, SEEK_SET);
  if (fread(&LineNum, 4, 1, InFH) != 1) {
    Error(MsgErrRead);
    goto CloseAll;
  }

  if (((SwapEndian ) && (LineNum == 0x02000000)) ||
      ((!SwapEndian) && (LineNum == 0x02))) {
    VegaCmdEx("Text \"  %s\" 1", MsgNotNeeded);
    goto CloseAll;
  }

  /**** Patch the file ****/

  LineNum = (SwapEndian) ? 0x02000000 : 0x02;


  fseek(InFH, 0x60, SEEK_SET);
  if ((fwrite(&LineNum, 4, 1, InFH) != 1) ||
      (fwrite("CREATED BY VEGA ZZ 2.4.0", 24, 1, InFH) != 1)) {
    Error(MsgErrWrite);
    goto CloseAll;
  }

  VegaCmdEx("Text \"  %s\" 1", MsgDone);

CloseAll:

  fclose(InFH );


  return 0;
}


/**** Show an error ****/

void Error(const char *Err)
{
  VegaCmdEx("MessageBox \"%s.\" \"%s\" 16", Err, MsgError);
}