module ActionView
  module Helpers
    module ActiveRecordHelper
      def error_messages_for(*params)
        better_msgs = {
          "Content type is not included in the list" => "That file type is not supported.",
          "Size is not included in the list" => "You must select a file smaller than 6MB in size."
          }
        options = params.extract_options!.symbolize_keys
        objects = params.collect {|name| instance_variable_get("@#{name}") }
        error_messages = objects.map {|o| o.errors.full_messages}
        unless error_messages.flatten!.empty?
          if options[:partial]
            render :partial => options[:partial],
                   :locals  => {:errors => error_messages}
          else
            header = "The following errors prevented this submission from being made:"
            error_list = error_messages.map {|m| content_tag(:li, better_msgs[m] || m)}
            contents = ''
            contents << content_tag(:h2, header)
            contents << content_tag(:ul, error_list)
            content_tag(:div, contents,
                        :class => 'errorExplanation',
                        :id    => 'errorExplanation')
          end
        else
          ''
        end
      rescue
        ''
      end
    end
  end
end