require 'delegate'

class DropCollectionExhibit < SimpleDelegator
  def initialize(drops, options)
    @links   = options.fetch :links, {}
    @context = options.fetch :context
    super Array(drops)
  end

  def render
    @context.render json:   { collection: collection },
                    status: :ok,
                    content_type: 'application/vnd.collection+json'
  end

protected

  def collection
    { version:   '1.0',
      href:      '/drops',
      items:     exhibited_drops,
      templates: templates
    }.merge(links)
  end

  def exhibited_drops
    map {|drop| DropExhibit.new(drop).as_json }
  end

  def links
    return {} unless previous_link or next_link

    { links: [].tap do |links|
        links << { rel: 'next',     href: next_link }     if next_link
        links << { rel: 'previous', href: previous_link } if previous_link
      end
    }
  end

  def templates
    [{
      rel:  '/rels/recover',
      href: '/drops?filter=trash',
      data: [{ name: 'drop_ids', value: [] }]
    }, {
      rel:  '/rels/remove',
      href: '/drops',
      data: [{ name: 'drop_ids', value: [] }]
    }]
  end

  def previous_link
    @links.fetch :previous, nil
  end

  def next_link
    @links.fetch :next, nil
  end
end