public function saveAfter(Post $previous = null)
{
// If the previous post is another 'discussion renamed' post, and it's
// by the same user, then we can merge this post into it. If we find
// that we've in fact reverted the title, delete it. Otherwise, update
// its content.
if ($previous instanceof static && $this->user_id === $previous->user_id) {
if ($previous->content[0] == $this->content[1]) {
$previous->delete();
} else {
$previous->content = static::buildContent($previous->content[0], $this->content[1]);
$previous->save();
}
return $previous;
}
$this->save();
return $this;
}