panel/app/views/posts/_form.haml

- unless post.errors.empty?
  .alert.alert-danger
    %ul
      - post.errors.each do |key, error|
        %li
          %strong
            = key.capitalize
          = [error].flatten.join("\n")

-# TODO: habilitar form_for
:ruby
  if post.new?
    url = site_posts_path(site)
    method = :post
  else
    url = site_post_path(site, post.id)
    method = :patch
  end

-# Comienza el formulario
= form_tag url, method: method, class: 'form post', multipart: true do

  -# Botones de guardado
  = render 'posts/submit', site: site, post: post

  -# Dibuja cada atributo
  :ruby
    post.attributes.each do |attribute|
      # El borrador se muestra distinto
      next if attribute == :draft

      metadata = post.send(attribute)
      type = metadata.type

      haml_io.write render("posts/attributes/#{type}",
                           post: post, attribute: attribute,
                           metadata: metadata, site: site)
    end

  -# Botones de guardado
  = render 'posts/submit', site: site, post: post