import static org.junit.Assert.*;
import java.util.Arrays;
import org.junit.Test;
import org.junit.Before;

public class InventoryTest {
    private static final int MAX_QUALITY = 50;
    private static final String AGED_BRIE_NAME = "Aged Brie";
    private static final String BACKSTAGE_PASS_NAME = "Backstage passes to a TAFKAL80ETC concert";
    private static final String NORMAL_ITEM_NAME = "+5 Dexterity Vest";

    private Item sulfuras;
    private Item normalItem;

    @Before
    public void setup(){
        sulfuras = new Item("Sulfuras, Hand of Ragnaros", 0, 80);
        normalItem = new Item(NORMAL_ITEM_NAME, 10, 20);
    }

    @Test
    public void testUpdate_ForSulfurasQuality() throws Exception {
        int expectedQuality = sulfuras.getQuality();
        Item[] items = {sulfuras};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(expectedQuality, sulfuras.getQuality());
    }
    @Test
    public void testUpdate_ForSulfurasSellIn() throws Exception {
        int expectedSellIn = sulfuras.getSellIn();
        Item[] items = {sulfuras};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(expectedSellIn, sulfuras.getSellIn());
    }

    @Test
    public void testUpdate_ForNormalItemSellIn() throws Exception {
        int expectedSellIn = normalItem.getSellIn() - 1;
        Item[] items = {normalItem};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(expectedSellIn, normalItem.getSellIn());
    }

    @Test
    public void testUpdate_ForNormalItemQuantity() throws Exception {
        int expectedQuality = normalItem.getQuality() - 1;
        Item[] items = {normalItem};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(expectedQuality, normalItem.getQuality());
    }

    @Test
    public void testUpdate_ForSoldOutItem() throws Exception {
        int minimumQuality = 0;
        Item normalItemWithMinimumQuality = new Item(NORMAL_ITEM_NAME, 10, minimumQuality);
        Item[] items = {normalItemWithMinimumQuality};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(minimumQuality, normalItemWithMinimumQuality.getQuality());
    }

    @Test
    public void testUpdate_ForNormalItemOnceTheSellInDatePassed() throws Exception {
        Item normalItemWithPassedSellDate = new Item(NORMAL_ITEM_NAME, -1, 25);
        int expectedQuality = normalItemWithPassedSellDate.getQuality() - 2;
        Item[] items = {normalItemWithPassedSellDate};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(expectedQuality, normalItemWithPassedSellDate.getQuality());
    }

    @Test
    public void testUpdate_AgedBrie() throws Exception {
        Item agedBrie = new Item(AGED_BRIE_NAME, 10, 25);
        int expectedQuality = agedBrie.getQuality() + 1;
        Item[] items = {agedBrie};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(expectedQuality, agedBrie.getQuality());
    }

    @Test
    public void testUpdate_WhenAgedBrieIsAtMaxQuality() throws Exception {
        Item agedBrie = new Item(AGED_BRIE_NAME, 10, MAX_QUALITY);
        Item[] items = {agedBrie};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(MAX_QUALITY, agedBrie.getQuality());
    }

    @Test
    public void testUpdate_ForBackstagePassesAfterTheConcertOccurred() throws Exception {
        Item backStagePass = new Item(BACKSTAGE_PASS_NAME, -1, 20);
        Item[] items = {backStagePass};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(0, backStagePass.getQuality());
    }

    @Test
    public void testUpdate_ForBackstagePassesQualityWhenTheConcertIsMoreThan10DaysAway() throws Exception {
        Item backStagePass = new Item(BACKSTAGE_PASS_NAME, 11, 20);
        int expectedQuality = backStagePass.getQuality() + 1;
        Item[] items = {backStagePass};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(21, backStagePass.getQuality());
    }

    @Test
    public void testUpdate_ForBackstagePassesWhenTheConcertIs10DaysOrLessAway() throws Exception {
        Item backStagePass = new Item(BACKSTAGE_PASS_NAME, 10, 27);
        int expectedQuality = backStagePass.getQuality() + 2;
        Item[] items = {backStagePass};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(expectedQuality, backStagePass.getQuality());
    }

    @Test
    public void testUpdate_ForBackstagePassesWhenTheConcertIs5DaysOrLessAway() throws Exception {
        Item backStagePass = new Item(BACKSTAGE_PASS_NAME, 5, 44);
        int expectedQuality = backStagePass.getQuality() + 3;
        Item[] items = {backStagePass};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(expectedQuality, backStagePass.getQuality());
    }

    @Test
    public void testUpdate_WhenBackstagePassesIsAtOrNeaerMaxQuality() throws Exception {
        Item backStagePassMoreThan10DaysAway = new Item(BACKSTAGE_PASS_NAME, 15, MAX_QUALITY);
        Item backStagePass10DaysAway = new Item(BACKSTAGE_PASS_NAME, 10, MAX_QUALITY - 1);
        Item backStagePass5DaysAway = new Item(BACKSTAGE_PASS_NAME, 5, MAX_QUALITY - 2);

        Item[] items = {backStagePassMoreThan10DaysAway, backStagePass10DaysAway, backStagePass5DaysAway};
        Inventory sut = new Inventory(items);

        sut.updateQuality();

        assertEquals(MAX_QUALITY, backStagePassMoreThan10DaysAway.getQuality());
        assertEquals(MAX_QUALITY, backStagePass10DaysAway.getQuality());
        assertEquals(MAX_QUALITY, backStagePass5DaysAway.getQuality());
    }
}