Simple form date picker input

gistfile1.rb

# Use f.input :start_date, as: :date_picker
class DatePickerInput < SimpleForm::Inputs::Base
  def input(wrapper_options = nil)
    input_html_classes.delete(:date_picker)
    input_html_classes << :string
    input_html_classes << 'datepicker'

    merged_input_options = merge_wrapper_options(input_html_options, wrapper_options)

    text_field = @builder.text_field(attribute_name, merged_input_options)
    hidden_field = @builder.hidden_field(attribute_name, {:id => tag_id(@builder, attribute_name) + "_alt"})

    text_field + hidden_field
  end

  private
    def tag_id(builder, attribute_name)
      "#{sanitized_object_name(builder.object_name)}_#{sanitized_method_name(attribute_name.to_s)}"
    end

    def sanitized_object_name(object_name)
      object_name.gsub(/\]\[|[^-a-zA-Z0-9:.]/, "_").sub(/_$/, "")
    end

    def sanitized_method_name(method_name)
      method_name.sub(/\?$/, "")
    end
end