module ExtraImageHelpers

  # creates an image link with thumbnail and caption:
  #   <div>
  #     <a href="/img/image.jpg">
  #       <img src="/img/image_klein.jpg">
  #     </a>
  #     <p>Caption</p>
  #   </div>
  #
  def image_with_thumb(name, options={})
    path = "/img/#{name}"
    options[:thumbnail] ||= default_thumbnail_for(name)

    asset_with_thumb(path, options)
  end

  # more general version of image_with_thumb, for pdfs and other assets (= not in the '/img' directory)
  def asset_with_thumb(path, options={})
    caption    = options.delete(:caption)
    thumb_name = options.delete(:thumbnail)
    thumb_path = "/img/#{thumb_name}"
    container_opts = options.delete(:container_opts) || {}

    image_link = content_tag(:a, href: path, class: "th") do
      image_tag(thumb_path, options)
    end

    caption_tag = content_tag :p, caption

    content_tag(:div, container_opts) do
      image_link << caption_tag
    end
  end

  private

  def default_thumbnail_for(image_name_with_ext)
    name, ext = image_name_with_ext.split(".")
    "#{name}_klein.#{ext}"
  end

end