turbovault-app/app/controllers/api/v1/collections_controller.rb

module Api
  module V1
    class CollectionsController < BaseController
      before_action :set_collection, only: [ :show, :update, :destroy ]

      def index
        @collections = current_user.collections.includes(:games).order(:name)
        render json: @collections, include: :games
      end

      def show
        render json: @collection, include: :games
      end

      def create
        @collection = current_user.collections.build(collection_params)

        if @collection.save
          render json: @collection, status: :created
        else
          render json: { errors: @collection.errors.full_messages }, status: :unprocessable_entity
        end
      end

      def update
        if @collection.update(collection_params)
          render json: @collection
        else
          render json: { errors: @collection.errors.full_messages }, status: :unprocessable_entity
        end
      end

      def destroy
        @collection.destroy
        head :no_content
      end

      private

      def set_collection
        @collection = current_user.collections.find(params[:id])
      end

      def collection_params
        params.require(:collection).permit(:name, :description, :parent_collection_id)
      end
    end
  end
end