public class Inventory {
    private Item[] items;

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

    public void updateQuality() {
        for (int i = 0; i < items.length; i++) {
            if (items[i].getName().equals("Aged Brie")
            || items[i].getName().equals("Backstage passes to a TAFKAL80ETC concert")) {
                //level 2 - quality
                if (items[i].getQuality() < 50) {
                    increaseQualityBy1(items[i]);
                    //level 3 - item type
                    if (items[i].getName() == "Backstage passes to a TAFKAL80ETC concert") {
                        //level 4 - sell in date
                        if (items[i].getSellIn() < 11) {
                            //level 5 - quality
                            if (items[i].getQuality() < 50) {
                                increaseQualityBy1(items[i]);
                            }
                        }
                        //level 4 - sell in date
                        if (items[i].getSellIn() < 6) {
                            //level 5 - quality
                            if (items[i].getQuality() < 50) {
                                increaseQualityBy1(items[i]);
                            }
                        }
                    }
                }
                //level 1 - item type
            } else {
                //level 2 - quality
                if (items[i].getQuality() > 0) {
                    //level 3 - item type
                    if (!items[i].getName().equals("Sulfuras, Hand of Ragnaros")) {
                        reduceQualityBy1(items[i]);
                    }
                }
            }

            if(!items[i].getName().equals("Sulfuras, Hand of Ragnaros")){
                updateSellInDays(items[i]);
            }
            updateExpiredItems(items[i]);
        }
    }

    public void reduceQualityBy1(Item item){
        item.setQuality(item.getQuality() -1);
    }

    public void increaseQualityBy1(Item item){
        item.setQuality(item.getQuality() + 1);
    }

    public void setQualityTo0(Item item){
        item.setQuality(item.getQuality() - item.getQuality());
    }

    public void updateSellInDays(Item item){
        item.setSellIn(item.getSellIn() - 1);
    }

    public void updateExpiredItems(Item item){
        if (item.getSellIn() < 0) {
            //level 2 - item type
            if (item.getName().equals("Aged Brie")) {
                //level 3 - quality
                if (item.getQuality() < 50) {
                    increaseQualityBy1(item);
                }
                //level 2 - item type
            } else if (item.getName().equals("Backstage passes to a TAFKAL80ETC concert")){
                setQualityTo0(item);
                //level 3 - item type
            } else {
                //level 4 - quality
                if (item.getQuality() > 0) {
                    //level 5 - item type
                    if (!item.getName().equals("Sulfuras, Hand of Ragnaros")) {
                        reduceQualityBy1(item);
                    }
                }
            }
        }
    }
}