use Image::ExifTool 'ImageInfo';

$ver = "1.0";

# converts AutoRotate codes to the needed number of degrees
%rotTable = (
	1 => 90,
	2 => 180,
	3 => 270
);

$quality = 92; # jpg quality similar to HQ setting on camera
$tempFN = "TEMP"; # temp filename

$|=1; # stdout buffering off

$mask = $ARGV[0]; # mask

if (!$mask or $mask =~ /^-/) {
	$me=$0;
	$me =~ s/.*[\/\\]//;
	print <<EOL;
EXIF Rotater $ver by Tyler Bletsch

Syntax:
	$me <filespec>

Rotates images depending on their AutoRotate EXIF tag.  Tested with Canon S410 
images.  Rotated images get their AutoRotate tag set to zero (so subsequent 
runs won't re-rotate).  ImageMagick must be in the path, and the the 
Image::ExifTool library for Perl is needed.

EOL
exit;
}

print "Globbing '$mask'...\n";
my @files = glob($mask);

print "Auto-rotating ".(scalar@files)." file".((scalar@files)==1?'':'s').":\n";

for $file (@files) {
	print "  Rotate '$file'? ";

	# Get hash of meta information tag names/values from an image
	%exif = %{ ImageInfo($file, {PrintConv=>0}) }; 
	
	$rot = $rotTable{$exif{AutoRotate}};
	if ($rot) {
		print "Yes, $rot degrees\n";
		$cmd = "convert -rotate $rot -quality $quality $file $file\n";
		print "    % $cmd\n";
		system $cmd;
		
		print "    Editing EXIF tags...\n\n";
		
		$exifTool = new Image::ExifTool; # Create a new Image::ExifTool object
		
		$exifTool->SetNewValue('AutoRotate',"None"); # Set a new value for tag

		if (-e $tempFN) { unlink $tempFN }

		# Write new meta information to a file
		$success = $exifTool->WriteInfo($file, $tempFN);
		
		if (-e $tempFN) { # write ok, make the temp file into the real one
			unlink $file;
			rename $tempFN, $file;
		} else {
			die "Error writing file with modified EXIF tags, aborting.\n";
		}
		
	} else {
		print "No\n";
	}
}