Carrierwave Uploader (with Cloudinary support) Input for ActiveAdmin's Formtastic Inputs

uploader_input.rb

class UploaderInput < Formtastic::Inputs::FileInput
  MAX_WIDTH_PIXELS = 300
  MAX_HEIGHT_PIXELS = 200

  def to_html
    input_wrapping do
      html_array = []
      html_array << label_html
      html_array << cache_html if method_changed?
      html_array << file_html
      html_array << existing_html if method_present?
      html_array << remove_html if method_was_present?
      html_array.join("").html_safe
    end
  end

  private

  def method_present?
    if object.respond_to?("#{method}?")
      object.send("#{method}?")
    else
      object.send(method).present?
    end
  end

  def method_changed?
    if object.respond_to?("#{method}_changed?")
      object.send("#{method}_changed?")
    else
      false
    end
  end

  def method_was_present?
    if !method_changed?
      method_present?
    else
      object.send("#{method}_was").present?
    end
  end

  def cache_html
    builder.hidden_field("#{method}_cache")
  end

  def file_html
    builder.file_field(method, input_html_options)
  end

  def cloudinary?
    object.send(method).is_a?(Cloudinary::CarrierWave) rescue false
  end

  def image_html
    if cloudinary?
      template.cl_image_tag(object.send(method).file.public_id, width: MAX_WIDTH_PIXELS, height: MAX_HEIGHT_PIXELS, crop: :limit)
    else
      template.image_tag(object.send(method).url, style: "max-width: #{MAX_WIDTH_PIXELS}px; max-height: #{MAX_HEIGHT_PIXELS}px;")
    end
  end

  def inner_existing_html
    if %w(jpg jpeg png gif).include?(object.send(method).file.format)
      image_html
    else
      object.send(method).file.filename
    end
  end

  def existing_html
    template.content_tag(:div, style: "margin-left: 20%; padding-top: 5px;") do
      template.link_to(inner_existing_html, object.send(method).url, target: :_blank)
    end
  end

  def remove_html
    template.content_tag(:div, style: "margin-left: 20%; padding-top: 5px;") do
      template.content_tag(:label, style: "float: none; width: auto;") do
        html_array = []
        html_array << template.check_box_tag("#{object_name}[remove_#{method}]", 1, false, id: "#{sanitized_object_name}_remove_#{sanitized_method_name}")
        html_array << "Remove"
        html_array.join(" ").html_safe
      end
    end
  end
end