using AcDream.App.Spells;
using AcDream.App.UI;
using AcDream.App.UI.Layout;
using AcDream.Core.Items;
using AcDream.Core.Selection;
using AcDream.Core.Spells;

namespace AcDream.App.Tests.UI.Layout;

public sealed class SpellcastingUiControllerTests
{
    private static (uint, int, int) NoTex(uint _) => (0u, 0, 0);

    [Fact]
    public void ImportedFixture_BindsAllTabs_AndTracksEquippedEndowment()
    {
        ImportedLayout layout = LayoutImporter.Build(
            FixtureLoader.LoadCombatInfos(), NoTex, datFont: null);
        var spellbook = new Spellbook();
        var objects = new ClientObjectTable();
        objects.AddOrUpdate(new ClientObject { ObjectId = 1u, Name = "Player" });
        var used = new List<uint>();
        using SpellcastingUiController? controller = Bind(
            layout, spellbook, objects, used.Add);

        Assert.True(controller is not null, DescribeBinding(layout));
        objects.AddOrUpdate(new ClientObject
        {
            ObjectId = 2u,
            Name = "Orb",
            Type = ItemType.Caster,
            WielderId = 1u,
            CurrentlyEquippedLocation = EquipMask.Held,
            SpellId = 2670u,
            IconId = 0x06001234u,
        });
        controller.Tick();

        UiElement host = Assert.IsAssignableFrom<UiElement>(
            layout.FindElement(SpellcastingUiController.EndowmentId));
        Assert.True(host.Visible);
        UiCatalogSlot slot = Assert.IsType<UiCatalogSlot>(host.Children[^1]);
        Assert.Equal(2u, slot.EntryId);
        Assert.Equal(2670u, slot.CatalogIconTexture);
        Assert.Equal(2u, slot.CatalogOverlayTexture);

        slot.OnEvent(new UiEvent(0, slot, UiEventType.Click));
        var cast = Assert.IsType<UiButton>(
            layout.FindElement(SpellcastingUiController.CastButtonId));
        cast.OnEvent(new UiEvent(0, cast, UiEventType.Click));
        Assert.Equal([2u], used);
    }

    [Fact]
    public void FavoriteDrop_IgnoresForeignInventoryPayload()
    {
        ImportedLayout layout = LayoutImporter.Build(
            FixtureLoader.LoadCombatInfos(), NoTex, datFont: null);
        var spellbook = new Spellbook();
        spellbook.OnSpellLearned(42u, 1f);
        spellbook.SetFavorite(0, 0, 42u);
        var objects = new ClientObjectTable();
        objects.AddOrUpdate(new ClientObject { ObjectId = 1u, Name = "Player" });
        using SpellcastingUiController? controller = Bind(
            layout, spellbook, objects, _ => { });

        Assert.True(controller is not null, DescribeBinding(layout));
        controller.Tick();
        UiElement group = Assert.IsAssignableFrom<UiElement>(layout.FindElement(0x100000AAu));
        UiItemList list = Descendants(group).OfType<UiItemList>().First();
        UiCatalogSlot slot = Assert.IsType<UiCatalogSlot>(list.GetItem(0));
        var foreign = new ItemDragPayload(9u, ItemDragSource.Inventory, 0, new UiItemSlot(), null);

        bool handled = slot.OnEvent(new UiEvent(
            0, slot, UiEventType.DropReleased, Payload: foreign));

        Assert.True(handled);
        Assert.Equal([42u], spellbook.GetFavorites(0));
    }

    [Fact]
    public void UnrelatedObjectUpdate_DoesNotRecreateFavoriteSlots()
    {
        ImportedLayout layout = LayoutImporter.Build(
            FixtureLoader.LoadCombatInfos(), NoTex, datFont: null);
        var spellbook = new Spellbook();
        spellbook.OnSpellLearned(42u, 1f);
        spellbook.SetFavorite(0, 0, 42u);
        var objects = new ClientObjectTable();
        objects.AddOrUpdate(new ClientObject { ObjectId = 1u, Name = "Player" });
        using SpellcastingUiController controller = Bind(
            layout, spellbook, objects, _ => { })!;
        UiElement group = layout.FindElement(0x100000AAu)!;
        UiItemList list = Descendants(group).OfType<UiItemList>().First();
        UiItemSlot before = list.GetItem(0)!;

        objects.AddOrUpdate(new ClientObject { ObjectId = 99u, Name = "Rock" });
        controller.Tick();

        Assert.Same(before, list.GetItem(0));
    }

    [Fact]
    public void ObjectTableClear_RemovesEquippedEndowmentAndCannotUseStaleGuid()
    {
        ImportedLayout layout = LayoutImporter.Build(
            FixtureLoader.LoadCombatInfos(), NoTex, datFont: null);
        var spellbook = new Spellbook();
        var objects = new ClientObjectTable();
        objects.AddOrUpdate(new ClientObject { ObjectId = 1u, Name = "Player" });
        objects.AddOrUpdate(new ClientObject
        {
            ObjectId = 2u,
            Name = "Orb",
            Type = ItemType.Caster,
            WielderId = 1u,
            CurrentlyEquippedLocation = EquipMask.Held,
            SpellId = 2670u,
        });
        var used = new List<uint>();
        using SpellcastingUiController controller = Bind(
            layout, spellbook, objects, used.Add)!;
        UiElement host = layout.FindElement(SpellcastingUiController.EndowmentId)!;
        UiCatalogSlot slot = Assert.IsType<UiCatalogSlot>(host.Children[^1]);
        slot.OnEvent(new UiEvent(0, slot, UiEventType.Click));

        objects.Clear();
        controller.Tick();

        Assert.False(host.Visible);
        Assert.Equal(0u, slot.EntryId);
        slot.OnEvent(new UiEvent(0, slot, UiEventType.DoubleClick));
        Assert.Empty(used);
    }

    private static SpellcastingUiController? Bind(
        ImportedLayout layout,
        Spellbook spellbook,
        ClientObjectTable objects,
        Action<uint> useItem)
    {
        var casting = new SpellCastingController(
            spellbook, () => null, () => 1u, () => { }, _ => { }, (_, _) => { }, _ => { });
        return SpellcastingUiController.Bind(
            layout, spellbook, casting, objects, () => 1u,
            spellId => spellId,
            item => item.ObjectId,
            useItem,
            new SelectionState(),
            (_, _, _) => { },
            (_, _) => { });
    }

    private static IEnumerable<UiElement> Descendants(UiElement root)
    {
        foreach (UiElement child in root.Children)
        {
            yield return child;
            foreach (UiElement nested in Descendants(child)) yield return nested;
        }
    }

    private static string DescribeBinding(ImportedLayout layout)
    {
        uint[] ids =
        [
            SpellcastingUiController.CastButtonId, SpellcastingUiController.EndowmentId,
            0x100000A3u, 0x100000AAu, 0x100005C2u, 0x100005C3u,
        ];
        return string.Join(", ", ids.Select(id =>
            $"{id:X8}={layout.FindElement(id)?.GetType().Name ?? "missing"}"));
    }
}