Gilded Rose

Items.cs

using System;

namespace gildedrose
{
	public class GildedRose 
    {

	//	private static List<Item> items = null;
	//
	//	public static void main(String[] args) {
	//		System.out.println("OMGHAI!");
	//		items = new ArrayList<Item>();
	//		items.add(new Item("+5 Dexterity Vest", 10, 20));
	//		items.add(new Item("Aged Brie", 2, 0));
	//		items.add(new Item("Elixir of the Mongoose", 5, 7));
	//		items.add(new Item("Sulfuras, Hand of Ragnaros", 0, 80));
	//		items.add(new Item("Backstage passes to a TAFKAL80ETC concert", 15, 20));
	//		items.add(new Item("Conjured Mana Cake", 3, 6));
	//		updateQuality(items);
	//	}
		public static void updateQuality(List<Item> items)
		{

			foreach (var currentItem in items) {
				currentItem.Update();
			}
		}
	}
	
	public interface IUpdateQuality 
	{
		void Update();
	}

	public class Sulfuras : Item 
	{
		public Sulfuras (int sellIn, int quality) : base("Sulfuras, Hand of Ragnaros", sellIn, quality) 
		{
		  
		}

		public override void Update()
		{
		}
	}

	public class ConjuredItem : Item
	{
	  	public ConjuredItem (int sellIn, int quality) : base("Conjured Mana Cake", sellIn, quality) 
	  	{
	  	  
	  	}

	  	public override void Update()
	  	{
			if (IsQuality) {
				DecreaseQuality();
			}

			sellIn--;

			if (sellIn < 0 && IsQuality) {
				DecreaseQuality();
			}		
	  	}

	}

	public class BackStagePass : Item 
	{
		public BackStagePass (int sellIn, int quality) : base("Backstage passes to a TAFKAL80ETC concert", sellIn, quality) 
		{
		  
		}

		public override void Update()
		{
			if (quality < 50) {
				IncreaseQuality();

				if (sellIn < 11) {
					IncreaseQuality();
				}

				if (sellIn < 6) {
					IncreaseQuality();
				}
			}

			sellIn--;

			if (sellIn < 0) {
				ResetQuality();
			}	
		}
	}

	public class AgedBrie : Item
	{
		public AgedBrie (int sellIn, int quality) : base("Aged Brie", sellIn, quality) 
		{
		  
		}

		public override void Update()
		{
			if (quality < 50) {
				IncreaseQuality();
			}

			sellIn --;

			if (sellIn < 0 && quality < 50) {
				IncreaseQuality();
			}	
		}
	}

	public class Item : IUpdateQuality {
	    public String name;
		public int sellIn; 
	    public int quality; 
	    
	    public Item(String name, int sellIn, int quality) {
			this.name = name;
			this.sellIn = sellIn;
			this.quality = quality;
		}

		public virtual void Update()
		{
			if (IsQuality) {
				DecreaseQuality();
			}

			sellIn --;

			if (sellIn < 0) {
				if (IsQuality) {
					DecreaseQuality();
				}
			}		
		}

		public bool IsQuality
		{
			get
			{
				return quality > 0;
			}
		}

		public void ResetQuality()
		{
			quality = (quality - quality);
		}

		public void DecreaseQuality()
		{
			quality = quality - 1;
		}

		public void IncreaseQuality()
		{
			quality = quality + 1;
		}
	}

}