+# cf: https://doc.dovecot.org/configuration_manual/mail_location/mbox/
+my %status2kw = (F => 'flagged', A => 'answered', R => 'seen', T => 'draft');
+# O (old/non-recent), and D (deleted) aren't in JMAP,
+# so probably won't be supported by us.
+sub mbox_keywords {
+ my $eml = $_[-1];
+ my $s = "@{[$eml->header_raw('X-Status'),$eml->header_raw('Status')]}";
+ my %kw;
+ $s =~ s/([FART])/$kw{$status2kw{$1}} = 1/sge;
+ sort(keys %kw);
+}
+
+# cf: https://cr.yp.to/proto/maildir.html
+my %c2kw = ('D' => 'draft', F => 'flagged', R => 'answered', S => 'seen');
+sub maildir_keywords {
+ $_[-1] =~ /:2,([A-Z]+)\z/i ?
+ sort(map { $c2kw{$_} // () } split(//, $1)) : ();
+}
+