# rubocop:disable Metrics/MethodLength
module UI
  ################## GENERIC TEMPLATE (aka CAROUSEL) #######################
  # https://developers.facebook.com/docs/messenger-platform/send-api-reference/generic-template
  class FBCarousel
    def initialize(elements)
      @template = {
        recipient: { id: nil },
        message: {
          attachment: {
            type: 'template',
            payload: {
              template_type: 'generic',
              image_aspect_ratio: 'horizontal',
              elements: parse_elements(elements)
            }
          }
        }
      }
    end

    # Sends the valid JSON to Messenger API
    def send(user)
      template = build(user)
      Bot.deliver(template, access_token: ENV['ACCESS_TOKEN'])
    end

    # Use this method to return a valid hash and save it for later
    def build(user)
      @template[:recipient][:id] = user.id
      @template
    end

    # set image aspect ratio to 'square'
    def square_images
      @template[:message][:attachment][:payload][:image_aspect_ratio] = 'square'
      self
    end

    # set image aspect ratio to 'square'
    def horizontal_images
      hrz = 'horizontal'
      @template[:message][:attachment][:payload][:image_aspect_ratio] = hrz
      self
    end

    private

    def parse_elements(elements)
      elements = [elements] if elements.class == Hash
      elements.map do |elt|
        elt[:buttons] = parse_buttons(elt[:buttons])
        elt
      end
    end

    def parse_buttons(buttons)
      return [] if buttons.nil? || buttons.empty?
      buttons.map do |button|
        button[:type] = button[:type].to_s
        button
      end
    end
  end
end