#! /usr/bin/perl -w

use Fcntl;
use Image::Info;
use Time::Local;
use strict;

my $indir;

# parse command line arguments
for (my $i = 0; $i <= $#ARGV; $i++) {
	my $arg = $ARGV[$i];
	my $nextarg = $ARGV[$i+1];
	$nextarg = "" unless (defined $nextarg);
	if ($arg eq '-i') {
		$indir = $nextarg;
	}
}

die "no input directory specified (use -i <indir>)" unless (defined $indir);

my @files;
opendir(DIR,$indir);
while (my $file = readdir(DIR)) {
	next unless ($file =~ /\.jpg$/i);
	push @files,$file;
}
foreach my $file (@files) {
	print "modifying '$file' ...\n";

	my ($date,$time,$aperture,$exposure,$speed,$focal) = exifInfo("$indir/$file");
	my ($year,$month,$mday) = split(/\-/,$date);
	my ($hour,$min,$sec) = split(/\:/,$time);
	my $stamp = timelocal($sec,$min,$hour,$mday,$month-1,$year);
	utime $stamp, $stamp, "$indir/$file";
	#print "$date $time = $stamp\n";
}
close (DIR);

exit;





################################################################################


sub exifInfo {
	my $infile = shift;
	my $exif = Image::Info::image_info($infile) or die;
	if (my $error = $exif->{error}) {
		die "Can't parse image info: $error\n";
	}

	
	my $aperture = "";
	$aperture = "f/" . eval ($exif->{FNumber}) if (defined $exif->{FNumber});
	my $exposure = "";
	$exposure = sprintf("%.3f", eval ($exif->{ExposureTime})) if (defined $exif->{ExposureTime});
	my $stamp = $exif->{DateTimeOriginal};
	$stamp = "" unless (defined $stamp);
	my $speed = $exif->{ISOSpeedRatings};
	$speed = "" unless (defined $speed);
	my $date = "";
	my $time = "";
	if ($stamp ne "") {
		($date,$time) = split(/ /,$stamp);
		$date =~ s/\:/\-/g;
	}
	my $focal = "";
	$focal = eval ($exif->{FocalLength}) . " mm" if (defined $exif->{FocalLength});

	return ($date,$time,$aperture,$exposure,$speed,$focal);
}