//--------------------------------------
//--- 010 Editor v6.0.2 Script File
//
// File: Rune Factory 4 save checksum
// Author: HenryEx
// Revision: 2
// Purpose: Repair checksum on modified save files
//--------------------------------------

RequiresFile();  // needs file to run on
OutputPaneClear();  // clear output

// Define variables
int64 size, fsize, pad, pos;
uint  savehash, magic;

// Initialize variables
fsize = FileSize();
magic = ReadUInt( 0 );
pad = 0xE0; // EoF block not used in hash
pos = 4; // offset after hash

// Throw error if file layout has changed

switch( fsize ) {
   case 0x1FC:
      Printf( "File size %Ld - File should be RF4 (3DS) save selection \n", fsize );
      break;
   case 0x2458:
      Printf( "File size %Ld - File should be RF4 (Switch) save selection \n", fsize );
      break;
   case 0x22400:
      Printf( "File size %Ld - File should be RF4 (3DS) save file \n", fsize );
      break;
   case 0x22480:
      Printf( "File size %Ld - File should be RF4 (Switch) save file \n", fsize );
      break;
   default:
      Printf( "Unexpected file size %Ld! Script failed!\n", fsize );
      Warning( "File mismatch, script terminated" );
      Exit( -1 );
}

// Change vars in case it's the save selector file rf4s.sav
if( magic == 1144276562 ) // string 'RF4D'
{
   Printf( "Calculating system save file hash...\n" );
   pos += 4;
   size = fsize - pos;
}
else {
   Printf( "Calculating save file hash...\n" );
   size = fsize - pad - pos;
}

savehash = Checksum( CHECKSUM_CRC32, pos, size, -1, -1 );
Printf( "New checksum: %x \n", savehash );

WriteUInt( pos - 4, savehash );
Printf( "Success! Save the file now." );