using AcDream.App.UI;
using Xunit;

namespace AcDream.App.Tests.UI;

public class UiItemListTests
{
    [Fact]
    public void IsLeafWidget() => Assert.True(new UiItemList().ConsumesDatChildren);

    [Fact]
    public void StartsWithOneCell_forSingleCellSlot()
    {
        var list = new UiItemList();
        Assert.Equal(1, list.GetNumUIItems());
        Assert.NotNull(list.GetItem(0));
    }

    [Fact]
    public void Cell_returnsTheFirstSlot()
    {
        var list = new UiItemList();
        Assert.Same(list.GetItem(0), list.Cell);
    }

    [Fact]
    public void CellEmptySprite_stamps_existing_and_future_cells()
    {
        var list = new UiItemList();                                 // ctor adds one default cell
        Assert.Equal(0x060074CFu, list.GetItem(0)!.EmptySprite);     // UiItemSlot default before set

        list.CellEmptySprite = 0x06004D20u;                          // a pack-slot sprite
        Assert.Equal(0x06004D20u, list.GetItem(0)!.EmptySprite);     // existing cell re-stamped

        list.AddItem(new UiItemSlot());
        Assert.Equal(0x06004D20u, list.GetItem(1)!.EmptySprite);     // new cell stamped
    }

    [Fact]
    public void CellEmptySprite_zero_leaves_the_UiItemSlot_default()
    {
        var list = new UiItemList();
        list.CellEmptySprite = 0u;
        Assert.Equal(0x060074CFu, list.GetItem(0)!.EmptySprite);     // unchanged default
    }

    [Fact]
    public void CatalogDrop_routes_payload_and_local_coordinates()
    {
        var list = new UiItemList();
        object payload = new();
        (object Payload, int X, int Y)? received = null;
        list.CatalogDropped = (value, x, y) => received = (value, x, y);

        bool handled = list.OnEvent(new UiEvent(
            0, list, UiEventType.DropReleased, Data1: 17, Data2: 9, Payload: payload));

        Assert.True(handled);
        Assert.NotNull(received);
        Assert.Same(payload, received.Value.Payload);
        Assert.Equal((17, 9), (received.Value.X, received.Value.Y));
    }

    [Fact]
    public void ScrollItemIntoView_moves_only_when_row_is_outside_viewport()
    {
        var list = new UiItemList
        {
            Width = 100f,
            Height = 64f,
            Columns = 1,
            CellWidth = 100f,
            CellHeight = 32f,
        };
        list.Flush();
        for (int i = 0; i < 5; i++) list.AddItem(new UiItemSlot());

        list.ScrollItemIntoView(3);
        Assert.Equal(64, list.Scroll.ScrollY);
        list.ScrollItemIntoView(2);
        Assert.Equal(64, list.Scroll.ScrollY);
        list.ScrollItemIntoView(0);
        Assert.Equal(0, list.Scroll.ScrollY);
    }
}