GildedRose-Refactoring-Kata/Java/src/main/java/com/gildedrose/GildedRose.java

package com.gildedrose;

class GildedRose {
	Item[] items;

	public GildedRose(Item[] items) {
		this.items = items;
	}

	public void updateQuality() {
		for (Item item : items) {
			updateItem(item);
		}
	}

	private void updateItem(Item item) {
		if (item.name.equals("Sulfuras, Hand of Ragnaros")) {
			return;
		}

		if (item.name.equals("Aged Brie")) {
			updateAgedBrie(item);
		} else if (item.name.equals("Backstage passes to a TAFKAL80ETC concert")) {
			updateBackstagePasses(item);

		} else {
			updateNormal(item);
		}
	}

	private void updateBackstagePasses(Item item) {
		item.sellIn = item.sellIn - 1;

		increaseQuality(item);

		if (item.sellIn < 10) {
			increaseQuality(item);
		}

		if (item.sellIn < 5) {
			increaseQuality(item);
		}

		if (item.sellIn < 0) {
			item.quality = item.quality - item.quality;
		}
	}

	private void updateNormal(Item item) {
		item.sellIn = item.sellIn - 1;

		decreaseQuality(item);
		if (item.sellIn < 0) {
			decreaseQuality(item);
		}
	}

	private void updateAgedBrie(Item item) {
		item.sellIn = item.sellIn - 1;

		increaseQuality(item);
		if (item.sellIn < 0) {
			increaseQuality(item);
		}
	}

	public void decreaseQuality(Item item) {
		if (item.quality > 0) {
			item.quality = item.quality - 1;
		}
	}

	public void increaseQuality(Item item) {
		if (item.quality < 50) {
			item.quality = item.quality + 1;
		}
	}
}