require_relative '../base'
require_relative 'error_message'

module CCS
  module Components
    module GovUK
      # = GOV.UK FormGroup
      #
      # This helper is used for generating the form group component from the Government Design Systems
      #
      # @!attribute [r] attribute
      #   @return [String,Symbol] Attribute that the form group is for
      # @!attribute [r] error_message
      #   @return [String] Text for the error message

      class FormGroup < Base
        private

        attr_reader :attribute, :error_message

        public

        # @param attribute [String,Symbol] the attribute that the form group is for
        # @param error_message [String] (nil) the error message to be displayed
        # @param options [Hash] options that will be used in customising the HTML
        #
        # @option options [String] :classes additional CSS classes for the form group HTML
        # @option options [Hash] :attributes ({}) any additional attributes that will added as part of the HTML

        def initialize(attribute:, error_message: nil, **options)
          super(**options)

          @options[:attributes][:id] ||= "#{attribute}-form-group"
          @options[:attributes][:class][..15] = 'govuk-form-group govuk-form-group--error' if error_message

          @attribute = attribute
          @error_message = error_message
        end

        # Generates the HTML for the GOV.UK Form Group component
        #
        # @yield HTML that will be contained within the 'govuk-form-group' div
        #
        # @yieldparam displayed_error_message [ActiveSupport::SafeBuffer] the HTML for the error message (if there is one)
        #
        # @return [ActiveSupport::SafeBuffer]

        def render
          tag.div(**options[:attributes]) do
            yield((ErrorMessage.new(message: error_message, attribute: attribute, context: context).render if error_message))
          end
        end

        # The default attributes for the form group

        DEFAULT_ATTRIBUTES = { class: 'govuk-form-group' }.freeze
      end
    end
  end
end