Ruby Test Cart

ruby.rb

require 'bigdecimal'

class Item

  attr_accessor :code, :name, :price 

  def initialize(code, name, price)
    @code = code
    @name = name
    @price = BigDecimal.new("#{price}")
  end

end

class Promotion

  def initialize
    @promo_rules = Hash.new
  end

  def add_promotion_rule(name, rule)
    @promo_rules[name] = rule
  end

  def remove_promotion_rule(name)
    if @promo_rules.has_key?(name)
      @promo_rules.delete(name)
    else
      puts "Promo rule not found"
    end
  end

  def promo_rules
    @promo_rules
  end
end

class Checkout

  def initialize(promotional_rules)
    @cart = []
    @promo_rules = promotional_rules.promo_rules #ugly
    @cart_total = BigDecimal.new(0)
  end

  def scan(*item)
    item.each {|item| @cart << item }
  end

  def apply_promo_rules
    puts @promo_rules.to_s
    @promo_rules.each_pair do |name,rule|
      rule.call @cart
    end
  end

  #This will shave trailing zeros but Rails has helpers for currency
  def total
    self.apply_promo_rules
    @cart.each { |item| cart_total =+ item.price }
    @cart_total.to_s
  end

  def cart
    @cart
  end

end

#Test run

item1 = Item.new('001', "Lavender heart", 9.25)
item2 = Item.new('002', "Personalised cufflinks", 45.00)
item3 = Item.new('003', "Kids T-Shirt", 19.95)

promotional_rules = Promotion.new

ten_percent_discount_over_sixty = Proc.new {
  cart.each { |item| cart_total += item.price }

  if cart_total >= 60.00
    cart_total =- cart_total * 0.1
  end
}

lavender_hearts_discount = Proc.new {

  count = @cart.each do |item|
    if item.code == '001'
      count += 1
    end
  end
  
  if count > 1
    @cart.each do |item|
      if item.code == '001' && item.price == 9.25
        item.price = 8.50
      end
    end
  else
    item.price = 9.25
  end
} 

promotional_rules.add_promotion_rule("lavender", lavender_hearts_discount)
promotional_rules.add_promotion_rule("ten percent", ten_percent_discount_over_sixty)

co = Checkout.new(promotional_rules)
co.scan(item1, item2, item3)