Fat controller

fat_controller.rb

class ThinController < ApplicationController

  def swipe_out
    @card = OysteCard.find(params[:id])
    authorize @card # uses a Pundit policy to determine whether or not the current user is authorised to update this card
    @journey_end_station = Station.find(params[:swipe_out][journey_end_station_id])
    if @card.journey_start_station.nil?
      flash[:alert] << "No start of journey recorded - you have been charged the maximum fare"
      @card.balance -= MAXIMUM_FARE
    else
      if @card.loaded_with_season_ticket?
        @fare = calculate_fare_with_season_ticket
      else
        @fare = calculate_fare
      end
    end

    if @fare > 0
      @card.balance -= @fare
      @card.record_transaction(@fare, @journey_end_station)
    end

    if @card.balance < 0
      flash[:alert] << 'You have no balance on your card - you must top up before travelling again'
      render :swipe_out
    else
      redirect_to card_show_path
    end
  end

  private

  def calculate_fare_with_season_ticket
    # all sorts of code to determine whether the season ticket covers the journey
    # or whether there is a fare to pay
  end

  def calculate_fare
    # work out fare
    zones_travelled = [@card.start_journey_station.zone, journey_end_station.zone].sort
    fare = FARES[zones_travelled]
    @card.balance -= fare
  end
end