refactoring topic command

bin/v2ex

@@ -28,11 +28,7 @@ command :topic do |c|
   c.action do |args, options|
     topic_id = args.first.to_i
     print_topic V2exCli::Engine.topic(topic_id), :show_content => true
-    info "\nreplies:\n"
-    V2exCli::Engine.replies(topic_id).each do |reply|
-      puts "#{reply[:member][:username]} ".ljust(25, '-')
-      print "#{reply[:content]}\n\n"
-    end
+    print_topic_replies V2exCli::Engine.replies(topic_id)
   end
 end
 
@@ -71,6 +67,19 @@ command :nodes do |c|
   end
 end
 
+def print_topic_replies(replies)
+  info "\nreplies:\n"
+
+  if replies.empty?
+    puts "No replies yet."
+  else
+    replies.each do |reply|
+      puts "#{reply[:member][:username]} ".ljust(25, '-')
+      print "#{reply[:content]}\n\n"
+    end
+  end
+end
+
 def print_user_meta(user)
   puts "#{user[:username]} - V2EX Member ##{user[:id]}"
   %w{twitter website location tagline}.map(&:to_sym).each do |key|