better rubixir command line tool

bin/rubixir

@@ -1,41 +1,87 @@
 #!/usr/bin/ruby
 
-if ARGV.size != 1
-  $stderr.puts "Usage: #{File.basename(__FILE__)} <app-name>"
-  exit 1
-end
+require 'optparse'
 
-app_name = ARGV[0]
+class RubixirCommandLine
+  def initialize(argv)
+    @argv = argv
+    OptionParser.new do |opts|
+      opts.banner = "Usage: #{File.basename(__FILE__)} [options] <args...>"
+    
+      opts.on('--update', 'Updates installation') { @mode = :update }
+      opts.on('--irb', 'Starts interactive prompt') { @mode = :irb }
+      opts.on('--create <app-name>', 'Creates new project') { |app_name| @mode = :create; @app_name = app_name }
+      opts.on('--help', 'Display this message') { die opts } 
+ 
+      begin
+        opts.parse!(@argv)
+      rescue OptionParser::InvalidOption => e
+        die e, opts
+      end
+      die opts unless @mode
+    end
+  end
 
-unless app_name.match(/^[a-zA-Z\d\s]+$/)
-  $stderr.puts "Invalid app name"
-  exit 1
-end
+  def run
+    case @mode
+      when :create
+        create_project
+      when :irb
+        start_irb
+      when :update
+        update_installation
+      else
+        die "unknown mode"
+    end
+  end
 
-if File.exist?(app_name)
-  $stderr.puts "Directory `#{app_name}' already exists"
-  exit 1
-end
+  private
 
-Dir.mkdir(app_name)
-Dir.chdir(app_name) do
-  File.open('Rakefile', 'w') do |io|
-    io.puts <<EOS
+  def create_project
+    unless @app_name.match(/^[a-zA-Z\d\s]+$/)
+      $stderr.puts "Invalid app name"
+      exit 1
+    end
+
+    if File.exist?(@app_name)
+      $stderr.puts "Directory `#{@app_name}' already exists"
+      exit 1
+    end
+ 
+    Dir.mkdir(@app_name)
+    Dir.chdir(@app_name) do
+      File.open('Rakefile', 'w') do |io|
+        io.puts <<EOS
 require 'rubygems'
 require 'rubixir/rake'
 
-Rubixir::CONFIG.app_name = '#{app_name}'
+Rubixir::CONFIG.app_name = '#{@app_name}'
 EOS
-  end
-  Dir.mkdir('app')
-  File.open('app/main.rb', 'w') do |io|
-    io.puts <<EOS
+      end
+      Dir.mkdir('app')
+      File.open('app/main.rb', 'w') do |io|
+        io.puts <<EOS
 class AppDelegate
   def application(application, didFinishLaunchingWithOptions:launchOptions)
     puts "Hello World!"
   end
 end
 EOS
+      end
+      Dir.mkdir('resources')
+    end
+  end
+
+  def start_irb
+  end
+
+  def update_installation
+  end
+
+  def die(*args)
+    $stderr.puts *args
+    exit 1
   end
-  Dir.mkdir('resources')
 end
+
+RubixirCommandLine.new(ARGV).run