oystercard.rb

require "./lib/journey_log"

class Oystercard

  MAXIMUM_BALANCE = 90
  MINIMUM_BALANCE = 1

  attr_reader :balance, :journey, :journey_log

  def initialize(journey_log: JourneyLog.new)
    @balance = 0
    @journey_log = journey_log
  end

  def top_up(amount_received)
    raise "Over limit of £#{MAXIMUM_BALANCE}" if above_maximum_balance?(amount_received)
    self.balance += amount_received
  end

  def touch_in(journey)
    raise "Too low funds" if below_minimum_balance?
    journey_log.start_journey(journey)
  end

  def touch_out(exit_station)
    journey_log.end_journey(exit_station)
    deduct(current_journey.fare)
  end

  private

  attr_writer :balance, :journey_log, :current_journey
  attr_reader :journey

  def deduct(amount_deducted)
    self.balance -= amount_deducted
  end

  def below_minimum_balance?
    balance < MINIMUM_BALANCE
  end

  def above_maximum_balance?(amount_received)
    balance + amount_received > MAXIMUM_BALANCE
  end

  def current_journey
    journey_log.current_journey
  end
end

class Oystercard
  def initialize(balance: BalanceCalculator.new, log: JourneyLog.new)
    @balance = balance
    @journey_log = log
  end

  def touch_in(station)
    balance.verify
    journey_log.start_journey(station)
  end

  def top_up(balance)
    balance.top_up(balance)
  end

  def touch_out(station)
    journey = journey_log.end_journey(station)
    balance.adjust(journey)
  end
end

class JourneyLog
  def initialize
    @journeys = []
  end

  def current_journey
    @journeys.current
  end

  def start_journey(station)
    already_in_journey?
    {start_journey: station, end_journey: station}
  end

  def already_in_journey?
    previous_journey_finished?
  end
end