using AcDream.App.UI;
using AcDream.App.UI.Layout;
namespace AcDream.App.Tests.UI.Layout;

public class ElementReaderTests
{
    // ── ToAnchors (decomp-backed: UIElement::UpdateForParentSizeChange @0x00462640) ─────────────

    /// <summary>
    /// Top edge (L=1,T=1,R=1,B=2): LeftEdge==1 → Left; RightEdge==1 → Right (stretch);
    /// TopEdge==1 → Top; BottomEdge==2 (not 1/4, top≠2) → no Bottom.
    /// This is the top chrome edge — it pins left, stretches width, pins top, fixed height.
    /// Real vitals values from format doc §11 (0x10000634).
    /// </summary>
    [Fact]
    public void ToAnchors_TopEdge_StretchesWidth()
    {
        var a = ElementReader.ToAnchors(left: 1, top: 1, right: 1, bottom: 2);
        Assert.True(a.HasFlag(AnchorEdges.Left));
        Assert.True(a.HasFlag(AnchorEdges.Top));
        Assert.True(a.HasFlag(AnchorEdges.Right));
        Assert.False(a.HasFlag(AnchorEdges.Bottom));
    }

    /// <summary>
    /// TL corner (L=1,T=1,R=2,B=2): LeftEdge==1 → Left; RightEdge==2 (not 1/4), left≠2 → no Right;
    /// TopEdge==1 → Top; BottomEdge==2, top≠2 → no Bottom. Fixed size, pinned top-left.
    /// Real vitals values from format doc §11 (0x10000633).
    /// </summary>
    [Fact]
    public void ToAnchors_TlCorner_PinsTopLeftFixed()
    {
        var a = ElementReader.ToAnchors(left: 1, top: 1, right: 2, bottom: 2);
        Assert.True(a.HasFlag(AnchorEdges.Left));
        Assert.True(a.HasFlag(AnchorEdges.Top));
        Assert.False(a.HasFlag(AnchorEdges.Right));
        Assert.False(a.HasFlag(AnchorEdges.Bottom));
    }

    /// <summary>
    /// TR corner (L=2,T=1,R=1,B=2): LeftEdge==2 → triggers Right (track-right); RightEdge==1 → Right;
    /// left≠1 → no Left; TopEdge==1 → Top; BottomEdge==2, top≠2 → no Bottom.
    /// Fixed-width element whose left and right both track the parent's right edge.
    /// Real vitals values from format doc §11 (0x10000635).
    /// </summary>
    [Fact]
    public void ToAnchors_TrCorner_TracksRight()
    {
        var a = ElementReader.ToAnchors(left: 2, top: 1, right: 1, bottom: 2);
        Assert.False(a.HasFlag(AnchorEdges.Left));
        Assert.True(a.HasFlag(AnchorEdges.Top));
        Assert.True(a.HasFlag(AnchorEdges.Right));
        Assert.False(a.HasFlag(AnchorEdges.Bottom));
    }

    /// <summary>
    /// Left edge (L=1,T=1,R=2,B=1): LeftEdge==1 → Left; RightEdge==2, left≠2 → no Right;
    /// TopEdge==1 → Top; BottomEdge==1 → Bottom. Pins left+top+bottom, fixed width, stretches height.
    /// Real vitals values from format doc §11 (0x10000636).
    /// </summary>
    [Fact]
    public void ToAnchors_LeftEdge_StretchesHeight()
    {
        var a = ElementReader.ToAnchors(left: 1, top: 1, right: 2, bottom: 1);
        Assert.True(a.HasFlag(AnchorEdges.Left));
        Assert.True(a.HasFlag(AnchorEdges.Top));
        Assert.False(a.HasFlag(AnchorEdges.Right));
        Assert.True(a.HasFlag(AnchorEdges.Bottom));
    }

    /// <summary>
    /// All-ones (L=1,T=1,R=1,B=1): all four flags fire — Left, Right, Top, Bottom.
    /// A piece pinned to all four sides stretches both horizontally and vertically.
    /// </summary>
    [Fact]
    public void ToAnchors_Meter_StretchesBoth()
    {
        var a = ElementReader.ToAnchors(left: 1, top: 1, right: 1, bottom: 1);
        Assert.True(a.HasFlag(AnchorEdges.Left));
        Assert.True(a.HasFlag(AnchorEdges.Top));
        Assert.True(a.HasFlag(AnchorEdges.Right));
        Assert.True(a.HasFlag(AnchorEdges.Bottom));
    }

    /// <summary>
    /// All-zero edge flags (prototype-only elements) fall back to Left|Top default.
    /// </summary>
    [Fact]
    public void EdgeFlagsToAnchors_AllZero_DefaultsToTopLeft()
    {
        var a = ElementReader.ToAnchors(left: 0, top: 0, right: 0, bottom: 0);
        Assert.Equal(AnchorEdges.Left | AnchorEdges.Top, a);
    }

    /// <summary>
    /// Value 3 on left and right axes contributes no Left/Right anchor;
    /// TopEdge==1 → Top; BottomEdge==1 → Bottom.
    /// left=3 (not 1/4) → no Left; right=3 (not 1/4), left≠2 → no Right;
    /// top=1 → Top; bottom=1 → Bottom. Result: Top|Bottom.
    /// </summary>
    [Fact]
    public void EdgeFlagsToAnchors_ValueThree_HorizAxes_YieldsTopBottom()
    {
        var a = ElementReader.ToAnchors(left: 3, top: 1, right: 3, bottom: 1);
        Assert.False(a.HasFlag(AnchorEdges.Left));
        Assert.True(a.HasFlag(AnchorEdges.Top));
        Assert.False(a.HasFlag(AnchorEdges.Right));
        Assert.True(a.HasFlag(AnchorEdges.Bottom));
    }

    // ── Merge ────────────────────────────────────────────────────────────────

    [Fact]
    public void Merge_BaseThenOverride_DerivedWins()
    {
        var base_ = new ElementInfo { Type = 0, FontDid = 0x40000000, Width = 150, Height = 16 };
        var derived = new ElementInfo { Type = 0, Width = 200 }; // overrides width, inherits font + height
        var merged = ElementReader.Merge(base_, derived);
        Assert.Equal(200, merged.Width);          // override
        Assert.Equal(16, merged.Height);          // inherited
        Assert.Equal(0x40000000u, merged.FontDid);// inherited
    }

    [Fact]
    public void Merge_DerivedHasFontDid_OverridesBase()
    {
        var base_ = new ElementInfo { FontDid = 0x40000000, Width = 100, Height = 10 };
        var derived = new ElementInfo { FontDid = 0x40000001, Width = 100 };
        var merged = ElementReader.Merge(base_, derived);
        Assert.Equal(0x40000001u, merged.FontDid);
    }

    [Fact]
    public void Merge_DerivedStateMediaOverridesBase()
    {
        var base_ = new ElementInfo();
        base_.StateMedia[""] = (0x06001000u, 1);
        base_.StateMedia["HideDetail"] = (0x06001001u, 1);

        var derived = new ElementInfo();
        derived.StateMedia[""] = (0x06002000u, 3); // overrides base default state

        var merged = ElementReader.Merge(base_, derived);
        // derived's "" overrides base's ""
        Assert.Equal((0x06002000u, 3), merged.StateMedia[""]);
        // base's "HideDetail" is kept (derived didn't provide it)
        Assert.Equal((0x06001001u, 1), merged.StateMedia["HideDetail"]);
    }

    [Fact]
    public void Merge_ChildrenComeFromDerived()
    {
        var base_ = new ElementInfo();
        base_.Children.Add(new ElementInfo { Id = 0x1u });

        var derived = new ElementInfo();
        derived.Children.Add(new ElementInfo { Id = 0x2u });

        var merged = ElementReader.Merge(base_, derived);
        // children must come from derived only
        Assert.Single(merged.Children);
        Assert.Equal(0x2u, merged.Children[0].Id);
    }
}