/*  dvdisaster: Additional error correction for optical media.
 *  Copyright (C) 2004-2009 Carsten Gnoerlich.
 *  Project home page: http://www.dvdisaster.com
 *  Email: carsten@dvdisaster.com  -or-  cgnoerlich@fsfe.org
 *
 *  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,
 *  or direct your browser at http://www.gnu.org.
 */

#include "dvdisaster.h"

/***
 *** Open the image file and fill in the respective Info struct.
 ***/

ImageInfo* OpenImageFile(EccHeader *eh, int mode)
{  ImageInfo *ii = NULL;
   gint64 img_size;
   int n,file_flags;
   gint64 fp_sector;
   unsigned char buf[2048];
   struct MD5Context md5ctxt;

   ii = g_malloc0(sizeof(ImageInfo));

   if(!(mode & PRINT_MODE))
     PrintLog(_("\nOpening %s"), Closure->imageName);

   if(!LargeStat(Closure->imageName, &img_size))
   {  if(mode & PRINT_MODE)  /* no error in print mode */ 
      {  FreeImageInfo(ii);
	 return NULL;
      }

      PrintLog(_(": not present.\n"));
      g_free(ii);
      Stop(_("Image file %s not present."),Closure->imageName);
      return NULL;
   }

   file_flags = mode & WRITEABLE_IMAGE ? O_RDWR : O_RDONLY;

   if(!(ii->file = LargeOpen(Closure->imageName, file_flags, IMG_PERMS)))
   {  if(Closure->guiMode)
      {  g_free(ii);
	 PrintLog(": %s", strerror(errno));
	 Stop(_("Can't open %s:\n%s"),Closure->imageName,strerror(errno));
      }
      else Stop(": %s", strerror(errno));
      return NULL;
   }

   ii->size = img_size;
   CalcSectors(img_size, &ii->sectors, &ii->inLast);

   if(!(mode & PRINT_MODE))
   { if(ii->inLast == 2048)
          PrintLog(_(": %lld medium sectors.\n"), ii->sectors);
     else PrintLog(_(": %lld medium sectors and %d bytes.\n"), 
		   ii->sectors-1, ii->inLast);
   }

   /*** Calculate md5sum of the fingerprint sector.
	Use sector specified by .ecc file if possible, 
	else use built-in default  */

   if(!eh)
        fp_sector = FINGERPRINT_SECTOR;
   else fp_sector = eh->fpSector;

   LargeSeek(ii->file, fp_sector*2048);

   MD5Init(&md5ctxt);
   n = LargeRead(ii->file, buf, 2048);

   if(n != 2048)
     Stop(_("could not read image sector %lld (only %d bytes):\n%s"),
	  fp_sector,n,strerror(errno));
   MD5Update(&md5ctxt, buf, n);
   MD5Final(ii->mediumFP, &md5ctxt);
   if(CheckForMissingSector(buf, fp_sector, NULL, 0) != SECTOR_PRESENT) /* No sector, no md5sum */
   {  memset(ii->mediumFP, 0 ,16);
      ii->fpValid=FALSE;
   }
   else ii->fpValid=TRUE;
   LargeSeek(ii->file, 0);                     /* rewind */

   return ii;
}

void FreeImageInfo(ImageInfo *ii)
{
   if(ii->file) 
     if(!LargeClose(ii->file))
       Stop(_("Error closing image file:\n%s"), strerror(errno));

   g_free(ii);
}


/***
 *** Open the ecc file and fill in the info stuff
 ***/

EccInfo* OpenEccFile(int mode)
{  EccInfo *ei = NULL; 
   int file_flags;

   /*** Sanity check for ecc file reads */

   if(!(mode & WRITEABLE_ECC))
   {  gint64 ecc_size;

      if(!LargeStat(Closure->eccName, &ecc_size))
      {  if(!(mode & PRINT_MODE))
	   Stop(_("Can't open %s:\n%s"),Closure->eccName,strerror(errno));
	 return NULL;
      }

      if(ecc_size < 4096)
	Stop(_("Invalid or damaged ecc file"));
   }
   
   /*** Open the ecc file  */

   ei = g_malloc0(sizeof(EccInfo));
   ei->eh = g_malloc0(sizeof(EccHeader));

   file_flags = mode & WRITEABLE_ECC ? O_RDWR | O_CREAT : O_RDONLY;

   if(!(ei->file = LargeOpen(Closure->eccName, file_flags, IMG_PERMS)))
   {  FreeEccInfo(ei);
      ei = NULL;

      if(!(mode & PRINT_MODE))  /* missing ecc file no problem in print mode */
	Stop(_("Can't open %s:\n%s"),Closure->eccName,strerror(errno));
      return NULL;
   }

   if(!(mode & WRITEABLE_ECC))
   {   int n = LargeRead(ei->file, ei->eh, sizeof(EccHeader));

       if(n != sizeof(EccHeader))
       {  FreeEccInfo(ei);
	  Stop(_("Can't read ecc header:\n%s"),strerror(errno));
       }

       /*** Endian annoyance */

#ifdef HAVE_BIG_ENDIAN
       SwapEccHeaderBytes(ei->eh);
#endif

       /*** See if we can use the ecc file */

       if(strncmp((char*)ei->eh->cookie, "*dvdisaster*", 12))
       {  FreeEccInfo(ei);
	  Stop(_("Invalid or damaged ecc file"));
       }

       VerifyVersion(ei->eh,1);

       ei->sectors = uchar_to_gint64(ei->eh->sectors);
       LargeSeek(ei->file, 0);
   }

   return ei;
}

void FreeEccInfo(EccInfo *ei)
{
   if(ei->file)
     if(!LargeClose(ei->file))
       Stop(_("Error closing error correction file:\n%s"), strerror(errno));

   if(ei->eh) g_free(ei->eh);
   g_free(ei);
}

/***
 *** Auxiliary functions
 ***/

/*
 * Append the given file suffix if none is already present
 */

char *ApplyAutoSuffix(char *filename, char *suffix)
{  char *out;

   if(!filename || !*filename || strrchr(filename, '.')) 
     return filename;

   out = g_strdup_printf("%s.%s",filename,suffix);
   g_free(filename);
   
   return out;
}

/*
 * See if we can handle the specified .ecc file
 */

int VerifyVersion(EccHeader *eh, int fatal)
{  
   if(Closure->version < eh->neededVersion)
   {  if(fatal)
       Stop(_("This .ecc file requires dvdisaster V%d.%d.%d or higher.\n"
	      "Please visit http://www.dvdisaster.com for an upgrade."),
	    eh->neededVersion/10000,
	    (eh->neededVersion%10000)/100,
	    eh->neededVersion%100);

      return 1;
   }

   return 0;
}

/* Remove the image file */

void UnlinkImage(GtkWidget *label)
{
   if(LargeUnlink(Closure->imageName))
   {    PrintLog(_("\nImage file %s deleted.\n"),Closure->imageName);

        if(Closure->guiMode)
	  SetLabelText(GTK_LABEL(label),
		       _("\nImage file %s deleted.\n"), Closure->imageName);
   }
   else 
   {  if(!Closure->guiMode)
       PrintLog("\n");

       ModalWarning(GTK_MESSAGE_ERROR, GTK_BUTTONS_OK, NULL,
		    _("Image file %s not deleted: %s\n"),
		    Closure->imageName, strerror(errno));
   }
}