osem/app/controllers/admin/rooms_controller.rb

module Admin
  class RoomsController < Admin::BaseController
    load_and_authorize_resource :conference, find_by: :short_title
    load_and_authorize_resource through: :conference

    def index
      authorize! :index, Room.new(conference_id: @conference.id)
    end

    def edit; end

    def new
      @room = @conference.rooms.new
    end

    def create
      @room = @conference.rooms.new(room_params)
      if @room.save
        flash[:notice] = 'Room successfully created.'
        redirect_to(admin_conference_rooms_path(conference_id: @conference.short_title))
      else
        flash[:error] = "Creating Room failed: #{@room.errors.full_messages.join('. ')}."
        render :new
      end
    end

    def update
      if @room.update_attributes(room_params)
        flash[:notice] = 'Room successfully updated.'
        redirect_to(admin_conference_rooms_path(conference_id: @conference.short_title))
      else
        flash[:error] = "Update Room failed: #{@room.errors.full_messages.join('. ')}."
        render :edit
      end
    end

    def destroy
      if @room.destroy
        flash[:notice] = 'Room successfully deleted.'
        redirect_to(admin_conference_rooms_path(conference_id: @conference.short_title))
      else
        flash[:error] = "Destroying room failed! #{@room.errors.full_messages.join('. ')}."
        redirect_to(admin_conference_rooms_path(conference_id: @conference.short_title))
      end
    end

    private

    def room_params
      params[:room]
    end
  end
end