class AbstractItem attr_reader :name, :sell_in, :quality def initialize(name:, sell_in:, quality:) @name, @sell_in, @quality = name, sell_in, quality @conjured = name.start_with? "Conjured" end def conjured? = @conjured def update! update_quality! @quality = 0 if quality < 0 @quality = 0 if conjured? && sell_in <= 0 @quality = max_quality if quality > max_quality update_sell_in! end private def max_quality = 50 def update_quality! = raise NotImplementedError def update_sell_in! = @sell_in -= 1 end class NormalItem < AbstractItem def self.name_regex = /.+/ # Should be checked last, after other item types. private def update_quality! quality_change = -1 quality_change -= 1 if sell_in <= 0 quality_change *= 2 if conjured? @quality += quality_change end end class AgedBrie < AbstractItem def self.name_regex = /Aged Brie/ private def update_quality! quality_change = 1 quality_change += 1 if sell_in <= 0 @quality += quality_change end end class Sulfuras < AbstractItem def self.name_regex = /Sulfuras, Hand of Ragnaros/ private def max_quality = 80 def update_quality! end def update_sell_in! @sell_in -= 1 if conjured? end end class BackstagePass < AbstractItem def self.name_regex = /Backstage passes to a TAFKAL80ETC concert/i private def update_quality! @quality = 0 and return if sell_in <= 0 quality_change = 1 quality_change += 1 if sell_in <= 10 quality_change += 1 if sell_in <= 5 quality_change -= 1 if conjured? @quality += quality_change end end # An item factory. Not named ItemFactory only because the tests expect `Item`. module Item ITEM_CLASSES = [AgedBrie, Sulfuras, BackstagePass, NormalItem] def self.new(name:, sell_in:, quality:) item_class(name).new(name:, sell_in:, quality:) end private_class_method def self.item_class(name) ITEM_CLASSES.find { name.match?(_1.name_regex) } end end class GildedRose def initialize(items) @items = items end def update! @items.each do |item| item.update! end end end