command_runner.rb

module Models
  module CommandRunner
    def self.included(base)
      base.class_eval do
        @commands = []
        class << self;
          attr_reader :commands;
          def command name, options=nil
            commands.add_command name, options
          end
        end
        def commands; self.class.commands; end
 
        class << @commands
          klass = self
          define_method(:add_command) do |command_name, options|
            if options && options[:params]
              klass.send(:define_method, :"#{command_name}_check_params") do |params|
                raise Errors::MissingCommandParameter.new("Params hash missing") unless params
                options[:params].each do |param_name|
                  raise Errors::MissingCommandParameter.new(param_name) unless params.include?(param_name)
                end
              end
            end
            send(:<<, command_name)
          end
        end
      end
    end
  end
end