require 'set'
module CheckboxSetHelper
  def self.included(klass)
    klass.extend(ClassMethods)
  end
  
  module ClassMethods
    def checkbox_set prop
      @checkbox_sets ||= []
      @checkbox_sets.push(prop.to_s)
      
      self.class_eval "def #{prop}_set; @#{prop}_set; end;"
      self.class_eval "def #{prop}_set= s; @#{prop}_set = s; end;"
      self.class_eval "def #{Inflector.pluralize(prop)}; self.#{prop}_set.to_a; end;"
    end
    
    def checkbox_sets
      @checkbox_sets
    end
  end
  
  def method_missing methodname, *args
    found = false

    self.class.checkbox_sets.each do |set_name|
      self.send(set_name + '_set=', Set.new) if !self.send(set_name + '_set')

      set = self.send(set_name + '_set')
      prefix = set_name + '_'

      if prefix.eql?(methodname.to_s[0..prefix.length-1])
        if "=".eql?(methodname.to_s[-1..-1])
          if args[0] == "1"
            set.add(methodname.to_s[prefix.length..-2].to_i)
          else
            set.delete(methodname.to_s[prefix.length..-2].to_i)
          end
        else
          return set.include?(methodname.to_s[prefix.length..-1].to_i)
        end
        found = true
        break
      end
    end

    super if !found
  end
end