check_boxes.rb

module ActionView
  module Helpers
    class FormBuilder
      Check = Struct.new(:box, :label)

      # Behaves almost exactly like the select method, but instead of generating a select tag,
      # generates Checks. These consist of two attributes, +box+ and +label+,
      # which are (unsurprisingly) the HTML for the check box and the label. Called without a block,
      # this method will return an array of check boxes. Called with a block, it will yield each
      # check box to your template.
      #
      # *Parameters:*
      #
      # * +method+ - The method name on the form_for object
      # * +choices+ - An array of arrays, the first value in each element is the text for the
      #   label, and the last is the value for the checkbox
      # * +options+ - An options hash to be passed through to the checkboxes
      #
      # *Examples:*
      #
      # <b>Simple formatting:</b>
      #
      #   <h4>How many heads?</h4>
      #   <ul>
      #     <% f.check_boxes :number_of_heads_in,
      #        [['One', 1], ['Two', 2], ['Three', 3]], :class => 'checkboxy' do |check| %>
      #        <li>
      #          <%= check.box %>
      #          <%= check.label %>
      #        </li>
      #     <% end %>
      #   </ul>
      #
      # This example will output the checkboxes and labels in an unordered list format.
      #
      # <b>Grouping:</b>
      #
      # Chain <tt>in_groups_of(<num>, false)</tt> on check_boxes like so:
      #   <h4>How many heads?</h4>
      #   <p>
      #     <% f.check_boxes(:number_of_heads_in,
      #        [['One', 1], ['Two', 2], ['Three', 3]],
      #        :class => 'checkboxy').in_groups_of(2, false) do |checks| %>
      #       <% checks.each do |check| %>
      #         <%= check.box %>
      #         <%= check.label %>
      #       <% end %>
      #       <br />
      #     <% end %>
      #   </p>
      def check_boxes(method, choices = [], options = {}, &block)
        unless choices.first.respond_to?(:first) && choices.first.respond_to?(:last)
          raise ArgumentError, 'invalid choice array specified'
        end
        collection_check_boxes(method, choices, :last, :first, options, &block)
      end

      # Just like +check_boxes+, but this time you can pass in a collection, value, and text method,
      # as with collection_select.
      #
      # Example:
      #
      #   <% f.collection_check_boxes :head_sizes_in, HeadSize.all,
      #       :id, :name, :class => 'headcheck' do |check| %>
      #     <%= check.box %> <%= check.label %>
      #   <% end %>
      def collection_check_boxes(method, collection, value_method, text_method, options = {}, &block)
        check_boxes = []
        collection.each do |choice|
          text = choice.send(text_method)
          value = choice.send(value_method)
          check = Check.new
          check.box = @template.check_box_tag(
            "#{@object_name}[#{method}][]",
            value,
            [@object.send(method)].flatten.include?(value),
            options.merge(:id => [@object_name, method.to_s, value.to_s.underscore].join('_'))
          )
          check.label = @template.label_tag([@object_name, method.to_s, value.to_s.underscore].join('_'),
                                        text)
          if block_given?
            yield check
          else
            check_boxes << check
          end
        end
        check_boxes unless block_given?
      end
    end
  end
end