using AcDream.App.UI;
using Xunit;

namespace AcDream.App.Tests.UI;

public class DragDropSpineTests
{
    // A spy handler used across the spine tests.
    private sealed class SpyHandler : IItemListDragHandler
    {
        public bool AcceptResult = true;
        public (UiItemList list, UiItemSlot cell, ItemDragPayload payload)? LastOver;
        public (UiItemList list, UiItemSlot cell, ItemDragPayload payload)? LastDrop;

        public bool OnDragOver(UiItemList list, UiItemSlot cell, ItemDragPayload p)
        { LastOver = (list, cell, p); return AcceptResult; }

        public void HandleDropRelease(UiItemList list, UiItemSlot cell, ItemDragPayload p)
        { LastDrop = (list, cell, p); }
    }

    [Fact]
    public void Payload_holdsAllFields()
    {
        var src = new UiItemSlot();
        var p = new ItemDragPayload(0x5001u, ItemDragSource.ShortcutBar, 3, src);
        Assert.Equal(0x5001u, p.ObjId);
        Assert.Equal(ItemDragSource.ShortcutBar, p.SourceKind);
        Assert.Equal(3, p.SourceSlot);
        Assert.Same(src, p.SourceCell);
    }

    [Fact]
    public void UiItemList_registerDragHandler_roundtrips()
    {
        var list = new UiItemList(_ => (0u, 0, 0));
        Assert.Null(list.DragHandler);
        var h = new SpyHandler();
        list.RegisterDragHandler(h);
        Assert.Same(h, list.DragHandler);
    }
}