Initial commit of fixed / updated code

Based on [gist](https://gist.github.com/1361085) by @glejeune

* added exit handler for cleaner end
* updated for newer ruby-mqtt gem
* fixed help text
* updated README

README.md

@@ -1,4 +1,38 @@
-mqtt-chat
-=========
+Simple MQTT-based chat room client written in Ruby
 
-Simple MQTT-based chat room client written in Ruby
+## Install
+
+1. Install and run an MQTT broker ([mosquitto](http://mosquitto.org) is one choice, this also works with [RabbitMQ](http://rabbitmq.com) version 3 which includes MQTT support)
+
+2. Install the [mqtt](http://github.com/njh/ruby-mqtt) and ncurses-ruby gems 
+
+(NB the plain ncurses gem is harder to natively compile)
+
+    sudo gem install mqtt ncurses-ruby
+
+## Run
+
+1. Run the client 
+
+    ruby ./mqtt-chat.rb <username>
+
+2. If you want to configure the app to run against an alternative MQTT broker running on a different host/post:
+
+modify
+
+    mqtt = MQTT::Client.new('localhost')
+
+replacing 'localhost' with the hostname or IP address of your chosen broker, optionally with a port number, e.g.
+
+    mqtt = MQTT::Client.new('m2m.eclipse.org', 1883)
+
+## Background
+
+Modified from simple AMQP-based and MQTT-based chat servers originally published as Gists by [glejeune](https://gist.github.com/glejeune)
+
+#### Changes from original
+
+* added exit handler for cleaner end
+* updated for newer ruby-mqtt gem
+* fixed help text
+* updated README

mqtt-chat.rb

@@ -0,0 +1,154 @@
+#!/usr/bin/env ruby
+
+require "rubygems"
+require "ncurses"
+require "mqtt"
+
+class ChatGui
+   def read_line(y, x,
+                 window     = Ncurses.stdscr,
+                 max_len    = (window.getmaxx - x - 1),
+                 string     = "",
+                 cursor_pos = 0)
+      loop do
+         window.mvaddstr(y,x,string)
+         window.move(y,x+cursor_pos)
+         ch = window.getch
+         case ch
+         when Ncurses::KEY_ENTER, ?\n.ord, ?\r.ord
+            return string
+         when Ncurses::KEY_BACKSPACE, 127
+            string = string[0...([0, cursor_pos-1].max)] + string[cursor_pos..-1]
+            cursor_pos = [0, cursor_pos-1].max
+            window.mvaddstr(y, x+string.length, " ")
+         when (" "[0].ord..255)
+            if (cursor_pos < max_len)
+               string[cursor_pos,0] = ch.chr
+               cursor_pos += 1
+            else
+               Ncurses.beep
+            end
+         else
+            Ncurses.beep
+         end
+      end
+   end
+
+   def add_message(message)
+      @messages += message.split("\n")
+      if @messages.size > @max_messages
+         @messages.shift
+      end
+
+      refresh_messages_window
+   end
+
+   def refresh_messages_window
+      @messages_window.clear
+      y = 0
+      @messages.each do |message|
+         @messages_window.mvaddstr(y, 0, message)
+         y = y + 1
+      end
+      @messages_window.refresh
+   end
+
+   def initialize(nick)
+      @messages = []
+      Ncurses.initscr
+      Ncurses.cbreak
+      Ncurses.noecho
+      Ncurses.keypad(Ncurses.stdscr, true)
+
+      @window = Ncurses.stdscr
+      @maxy = @window.getmaxy - 1
+      @maxx = @window.getmaxx - 1
+
+      @prompt_window = Ncurses.newwin(2, @maxx, @maxy - 2, 0)
+      @prompt = "#{nick} >"
+
+      @messages_window = Ncurses.newwin(@maxy - 2, @maxx, 0, 0)
+      @max_messages = @messages_window.getmaxy
+   end
+
+   def run(&b)
+      loop do
+         # refresh_messages_window
+
+         @prompt_window.mvaddstr(0, 0, "-"*@maxx)
+         @prompt_window.mvaddstr(1, 0, @prompt)
+         message = read_line(1, @prompt.length + 1, @prompt_window)
+         yield message
+         @prompt_window.clear
+      end
+   end
+
+   def quit
+      Ncurses.endwin
+   end
+end
+
+# -- main --
+
+def help(gui)
+   gui.add_message <<EOH
+   /help : display this help
+   /me <message> : send an action message
+   /privmsg <nickname> <message> : send a private message
+   /quit : Quit MQTT chat
+   /who : ask who is here
+EOH
+end
+
+begin
+
+   nickname = ARGV[0]
+   raise "Usage : #{$0} <nickname>" if nickname.nil?
+
+gui = ChatGui.new(nickname)
+mqtt = MQTT::Client.new('localhost')
+
+mqtt.connect do |client|
+   client.subscribe('chat/public')
+   client.subscribe('chat/system')
+   client.subscribe("chat/private/#{nickname}")
+
+   client.publish 'chat/public', "** #{nickname} enter"
+
+   Thread.new do
+      gui.run do |message|
+         case message
+         when /^\/quit\s*(.*)/
+            client.publish 'chat/public', "** #{nickname} has quit (#{$1})"
+            client.disconnect
+            gui.quit
+            exit 1
+         when /^\/privmsg\s*([^\s]*)\s*(.*)/
+            client.publish "chat/private/#{$1}", ">> [#{Time.now.strftime('%H:%M:%S')}] #{nickname} : #{$2}"
+            client.publish "chat/private/#{nickname}", ">> [#{Time.now.strftime('%H:%M:%S')}] #{nickname} : #{$2}"
+         when /^\/who/
+            client.publish "chat/system", nickname
+         when /^\/help/
+            help gui
+         else
+            client.publish 'chat/public', "[#{Time.now.strftime('%H:%M:%S')}] #{nickname} : #{message}"
+         end
+      end
+   end
+
+   loop do
+      topic,message = client.get
+      if topic =~ /chat\/system/
+         client.publish "chat/private/#{message}", "-- #{nickname} is here"
+      else
+         gui.add_message message
+      end
+   end
+end
+
+rescue Interrupt
+  puts "\nexiting..."
+rescue Exception => e
+  puts e
+
+end