module DateWithOptionalTime
  module ActiveRecord
    module Base
      
      def self.included(base)
        base.extend(ClassMethods)
      end
      
      module ClassMethods
        def date_with_optional_time(attributes)
          class_eval <<-EOV
            attributes.each do |a|
              a = a.to_s

              # i think this would work
              define_method obj_time
                send "#{a}_time"
              end

              define_method obj_date
                send "#{a}_date"
              end
              
              define_method(a+"_time_display") do
                hours = (obj_time / 100).floor
                minutes = obj_time - (hours * 100)
                sprintf('%02d:%02d', hours, minutes)
              end
              
              define_method(a+"_time_display=") do |value|
                send(a+"_time_will_change!") if obj_time == 0 && value.blank?
                obj_time = value.split(':').join
              end
              
              define_method(a+"_datetime") do
                if obj_date
                  dt_arr = [obj_date.year, obj_date.month, obj_date.day]
                  time = obj_time || 0
                  hours = (time / 100).floor
                  minutes = time - (hours * 100)
                  dt_arr += [hours,minutes]
                  DateTime.new(*dt_arr)
                end
              end
            end
          EOV
        end
      end
    end
  end
end