1 files changed, 26 insertions, 0 deletions
diff --git a/lib/Sietima/Role/SubjectTag.pm b/lib/Sietima/Role/SubjectTag.pm
new file mode 100644
index 0000000..1daa662
--- /dev/null
+++ b/lib/Sietima/Role/SubjectTag.pm
@@ -0,0 +1,26 @@
+package Sietima::Role::SubjectTag;
+use 5.024;
+use Moo::Role;
+use Types::Standard qw(Str);
+use namespace::clean;
+
+has subject_tag => (
+    is => 'ro',
+    isa => Str,
+    required => 1,
+);
+
+around munge_mail => sub {
+    my ($orig,$self,$mail) = @_;
+
+    my $tag = '['.$self->subject_tag.']';
+    my $subject = $mail->header_str('Subject');
+    unless ($subject =~ m{\Q$tag\E}) {
+        $mail->header_str_set(
+            Subject => "$tag $subject",
+        );
+    }
+    return $self->$orig($mail);
+};
+
+1;