content.rb

class ArticlePresenter  
  DEFAULT_OFFSET  = 100
  READ_MORE_REGEX = /<!--more-->/
  
  def content(should_truncate)
    content = article.content.clone
    index   = content.index(READ_MORE_REGEX) || DEFAULT_OFFSET

    if should_truncate
      content = content.truncate(index)
      button  = read_more_button(article)
    else
      content.sub! READ_MORE_REGEX, ''
    end

    html = MarkdownService.instance.render(content) + button.presence
    content_tag :div, html, class: 'ui justified text container'
  end
  
  private
  
  def read_more_button(article)
    link_to 'Read more', article, class: 'ui green basic button'
  end
end