+sub sort_ts {
+ sort {
+ (eval { $a->topmost->message->header('X-PI-TS') } || 0) <=>
+ (eval { $b->topmost->message->header('X-PI-TS') } || 0)
+ } @_;
+}
+
+sub rsort_ts {
+ sort {
+ (eval { $b->topmost->message->header('X-PI-TS') } || 0) <=>
+ (eval { $a->topmost->message->header('X-PI-TS') } || 0)
+ } @_;
+}
+
+# accumulate recent topics if search is supported
+# returns 1 if done, undef if not
+sub add_topic {
+ my ($state, $node, $level) = @_;
+ return unless $node;
+ my $child_adjust = 1;
+
+ if (my $x = $node->message) {
+ $x = $x->header_obj;
+ my $subj;
+
+ $subj = $x->header('Subject');
+ $subj = $state->{srch}->subject_normalized($subj);
+
+ if (++$state->{subjs}->{$subj} == 1) {
+ push @{$state->{order}}, [ $level, $subj ];
+ }
+
+ my $mid = mid_clean($x->header_raw('Message-ID'));
+
+ my $ts = $x->header('X-PI-TS');
+ my $exist = $state->{latest}->{$subj};
+ if (!$exist || $exist->[1] < $ts) {
+ $state->{latest}->{$subj} = [ $mid, $ts ];
+ }
+ } else {
+ # ghost message, do not bump level
+ $child_adjust = 0;
+ }
+
+ add_topic($state, $node->child, $level + $child_adjust);
+ add_topic($state, $node->next, $level);
+}
+
+sub dump_topics {
+ my ($state) = @_;
+ my $order = $state->{order};
+ my $subjs = $state->{subjs};
+ my $latest = $state->{latest};
+ return "\n[No topics in range]</pre>" unless (scalar @$order);
+ my $dst = '';
+ my $pfx;
+ my $prev = 0;
+ my $prev_attr = '';
+ while (defined(my $info = shift @$order)) {
+ my ($level, $subj) = @$info;
+ my $n = delete $subjs->{$subj};
+ my ($mid, $ts) = @{delete $latest->{$subj}};
+ $mid = PublicInbox::Hval->new_msgid($mid)->as_href;
+ $subj = PublicInbox::Hval->new($subj)->as_html;
+ $pfx = indent_for($level);
+ my $nl = $level == $prev ? "\n" : '';
+ my $dot = $level == 0 ? '' : '` ';
+ $dst .= "$nl$pfx$dot<a\nhref=\"$mid/t/#u\"><b>$subj</b></a>\n";
+
+ my $attr;
+ $ts = fmt_ts($ts);
+ $attr = " $ts UTC";
+
+ # $n isn't the total number of posts on the topic,
+ # just the number of posts in the current results
+ # window, so leave it unlabeled
+ $n = $n == 1 ? '' : " ($n+ messages)";
+
+ if ($level == 0 || $attr ne $prev_attr) {
+ my $mbox = qq(<a\nhref="$mid/t.mbox.gz">mbox.gz</a>);
+ my $atom = qq(<a\nhref="$mid/t.atom">Atom</a>);
+ $pfx .= INDENT if $level > 0;
+ $dst .= $pfx . $attr . $n . " - $mbox / $atom\n";
+ $prev_attr = $attr;
+ }
+ }
+ $dst .= '</pre>';
+}
+
+sub emit_index_topics {
+ my ($state, $fh) = @_;
+ my $off = $state->{ctx}->{cgi}->param('o');
+ $off = 0 unless defined $off;
+ $state->{order} = [];
+ $state->{subjs} = {};
+ $state->{latest} = {};
+ my $max = 25;
+ my %opts = ( offset => int $off, limit => $max * 4 );
+ while (scalar @{$state->{order}} < $max) {
+ my $res = $state->{srch}->query('', \%opts);
+ my $nr = scalar @{$res->{msgs}} or last;
+
+ for (rsort_ts(thread_results(load_results($res), 1)->rootset)) {
+ add_topic($state, $_, 0);
+ }
+ $opts{offset} += $nr;
+ }
+
+ $fh->write(dump_topics($state));
+ $opts{offset};
+}
+