use 5.010;
use strict;
use warnings;

# Dateien auflisten und sortieren
my @files = sort glob '*.mkv';

# Segment-UIDs via mkvinfo auslesen
my @uids = map {
    my $file = $_;

    open my $mkvinfo, '-|', qw/mkvinfo --ui-language en/, $file
	or die "Couldn't run mkvinfo on $file: $!";
    
    my $uid;
    while (my $_ = <$mkvinfo>) {
	if (/\+ Segment UID:\s+0x(.*)$/) {
	    $uid = $1;
	    last;
	}
    }

    close $mkvinfo
	or die "Error running mkvinfo on $file: $!";

    warn "Couldn't determine UID for $file" unless (defined $uid);

    $uid
} @files;

# Ueber alle Dateien iterieren und Felder setzen
for ($[ .. $#files) {
    my $file = $files[$_];

    my $prev_uid = ($_ - 1 >= $[ ? $uids[$_ - 1] : undef);
    my $next_uid = ($_ + 1 <= $#uids ? $uids[$_ + 1] : undef);

    my @options;
    push @options, '--set', "prev-uid=$prev_uid" if (defined $prev_uid);
    push @options, '--set', "next-uid=$next_uid" if (defined $next_uid);

    if (@options) {
	system('mkvpropedit', $file, qw/--edit info/, @options) == 0
	    or die "Couldn't run mkvpropedit on $file: status $?"
    }
}