osem-fcy/app/controllers/ticket_purchases_controller.rb

class TicketPurchasesController < ApplicationController
  before_filter :authenticate_user!
  load_resource :conference, find_by: :short_title
  authorize_resource :conference_registrations, class: Registration

  def create
    TicketPurchase.by_conference(@conference).unpaid.by_user(current_user).destroy_all
    message = TicketPurchase.purchase(@conference, current_user, params[:tickets][0])
    if message.blank?
      if current_user.ticket_purchases.by_conference(@conference).unpaid.any?
        redirect_to new_conference_payment_path, notice: 'Please pay here to purchase tickets.'
      else
        redirect_to conference_conference_registration_path(@conference.short_title)
      end
    else
      redirect_to conference_conference_registration_path(@conference.short_title),
                  error: "Oops, something went wrong with your purchase! #{message}"
    end
  end

  private

  def ticket_purchase_params
    params.require(:ticket_purchase).permit(:ticket_id, :user_id, :conference_id, :quantity)
  end
end