class Grabbers::FacebookAttachments

  def initialize(api_client)
    @api_client = api_client
  end

  def grab_for_post(post)
    result = { 'attachment' => { 'media' => [] }}

    begin
      post = @api_client.get_object(post['id'], fields: 'attachments')

      post_attachments(post).each do |subattachment|
        if subattachment['target'].present? && subattachment['target']['id'].present?
          attachment = grab_attachment_by(subattachment['target']['id'])

          if attachment.present?
            attachment['photo']['fbid'] = subattachment['target']['id']
            attachment['href']          = subattachment['target']['url']

            result['attachment']['media'] << attachment
          end
        end
      end

      if result['attachment']['media'].compact.empty?
        result['attachment']['media'] = default_attachments_for(post)
      end
    rescue Exception => error
      ErrorsService.log(error, title: 'Cant grab attachments for post', data: {post: post})
    end

    result
  end

  private

  def grab_attachment_by(object_id)
    begin
      attachment = @api_client.get_object(object_id)

      image = attachment['images'].max_by { |image| [image['width'], image['height']].max }

      {'type' => 'photo', 'src' => image['source'], 'photo' => {'width' => image['width'], 'height' => image['height']}  }
    rescue Exception
      return nil
    end
  end

  def default_attachments_for(post)
    post_attachments(post).map do |subattachment|
      {
        'type'  => 'photo',
        'src'   => image_src(subattachment),
        'href'  => image_url(subattachment),
        'photo' => {
          'fbid'   => image_fbid(subattachment),
          'width'  => subattachment['media']['image']['width'],
          'height' => subattachment['media']['image']['height']
        }
      }
    end
  end

  def image_url(subattachment)
    subattachment['target'].present? ? subattachment['target']['url'] : subattachment['url']
  end

  def image_src(subattachment)
    begin
      src = subattachment['media']['image']['src']

      return CGI::parse(src)['url'].first if src.include?('safe_image.php')

      src
    rescue Exception => error
      ErrorsService.log(error, title: 'Cant process image src', data: {subattachment: subattachment}, skip_airbrake_notification: true)
      ''
    end
  end

  def image_fbid(subattachment)
    subattachment['target'].present? ? subattachment['target']['id'] : subattachment['id']
  end

  def post_attachments(post)
    return post['attachments']['data'].first['subattachments']['data'] if post['attachments']['data'].first['subattachments'].present?
    return post['attachments']['data']                                 if post['attachments']['data'].first['media'].present?

    []
  end
end