view: show more nearby messages in flat thread view

Context is important, but so is conserving precious screen
space.  Decisions :<

1 files changed, 36 insertions, 6 deletions

diff --git a/lib/PublicInbox/View.pm b/lib/PublicInbox/View.pm
index 9393d443..0b96bda8 100644
--- a/lib/PublicInbox/View.pm
+++ b/lib/PublicInbox/View.pm
@@ -146,6 +146,13 @@ sub index_entry {
         $rv .= $more ? "\n\n" : "\n";
 }
 
+sub pad_link ($$;$) {
+        my ($mid, $level, $s) = @_;
+        $s ||= '...';
+        my $id = id_compress($mid, 1);
+        (' 'x19).indent_for($level).th_pfx($level)."<a\nhref=#r$id>($s)<a>\n";
+}
+
 sub _th_index_lite {
         my ($mid_raw, $irt, $id, $ctx) = @_;
         my $rv = '';
@@ -155,16 +162,24 @@ sub _th_index_lite {
         my $map = $mapping->{$mid_raw};
         my $nr_c = scalar @{$map->[0]};
         my $nr_s = 0;
+        my $level = $map->[4];
+        my $idx = $map->[3];
         if (defined $irt) {
                 my $irt_map = $mapping->{$irt};
                 my $siblings = $irt_map->[0];
                 $nr_s = scalar(@$siblings) - 1;
-                $nr_s = 0 if $nr_s < 0;
                 $rv .= $pad . $irt_map->[1];
-                my $idx = $map->[3];
                 if ($idx > 0) {
                         my $prev = $siblings->[$idx - 1];
-                        $rv .= $pad . $mapping->{$prev->messageid}->[1];
+                        my $pmid = $prev->messageid;
+                        if ($idx > 2) {
+                                my $s = ($idx - 1). ' preceding siblings ...';
+                                $rv .= pad_link($pmid, $level, $s);
+                        } elsif ($idx == 2) {
+                                my $ppmid = $siblings->[0]->messageid;
+                                $rv .= $pad . $mapping->{$ppmid}->[1];
+                        }
+                        $rv .= $pad . $mapping->{$pmid}->[1];
                 }
         }
         my $s_s = nr_to_s($nr_s, 'sibling', 'siblings');
@@ -175,10 +190,25 @@ sub _th_index_lite {
         $rv .= "<b>@ $this";
         my $node = $map->[2];
         if (my $child = $node->child) {
-                $rv .= $pad . $mapping->{$child->messageid}->[1];
+                my $cmid = $child->messageid;
+                $rv .= $pad . $mapping->{$cmid}->[1];
+                if ($nr_c > 2) {
+                        my $s = ($nr_c - 1). ' more replies';
+                        $rv .= pad_link($cmid, $level + 1, $s);
+                } elsif (my $cn = $child->next) {
+                        $rv .= $pad . $mapping->{$cn->messageid}->[1];
+                }
         }
         if (my $next = $node->next) {
-                $rv .= $pad .  $mapping->{$next->messageid}->[1];
+                my $nmid = $next->messageid;
+                $rv .= $pad . $mapping->{$nmid}->[1];
+                my $nnext = $nr_s - $idx;
+                if ($nnext > 2) {
+                        my $s = ($nnext - 1).' subsequent siblings';
+                        $rv .= pad_link($nmid, $level, $s);
+                } elsif (my $nn = $next->next) {
+                        $rv .= $pad . $mapping->{$nn->messageid}->[1];
+                }
         }
         $rv .= "<a\nhref=#e$id\nid=m$id>_<a> <a\nhref=#r$id\n>$s_s, $s_c</a>\n";
 }
@@ -203,7 +233,7 @@ sub pre_thread  {
                 $idx = scalar @$m;
                 push @$m, $node;
         }
-        $mapping->{$node->messageid} = [ [], '', $node, $idx ];
+        $mapping->{$node->messageid} = [ [], '', $node, $idx, $level ];
         skel_dump($ctx, $level, $node);
 }