acdream/tests/AcDream.App.Tests/UI/Layout/ElementReaderTests.cs

using System.Numerics;
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);
    }

    // ── HJustify / VJustify — Merge propagation ─────────────────────────────

    /// <summary>
    /// When the derived element has a non-Center HJustify, the derived value wins
    /// (same "non-default wins" rule as FontDid).
    /// </summary>
    [Fact]
    public void Merge_DerivedHJustifyRight_OverridesBaseCenter()
    {
        var base_   = new ElementInfo { HJustify = HJustify.Center };
        var derived = new ElementInfo { HJustify = HJustify.Right };
        var merged  = ElementReader.Merge(base_, derived);
        Assert.Equal(HJustify.Right, merged.HJustify);
    }

    /// <summary>
    /// When the derived element has the default HJustify (Center), the base value
    /// is inherited — Center from the derived does NOT override a Left base.
    /// </summary>
    [Fact]
    public void Merge_DerivedHJustifyCenter_InheritsBaseLeft()
    {
        var base_   = new ElementInfo { HJustify = HJustify.Left };
        var derived = new ElementInfo { HJustify = HJustify.Center };   // default — no explicit dat property
        var merged  = ElementReader.Merge(base_, derived);
        Assert.Equal(HJustify.Left, merged.HJustify);
    }

    /// <summary>
    /// VJustify=Top from the base propagates when the derived element has no explicit
    /// (Center) vertical justification.
    /// </summary>
    [Fact]
    public void Merge_BaseVJustifyTop_InheritedWhenDerivedIsCenter()
    {
        var base_   = new ElementInfo { VJustify = VJustify.Top };
        var derived = new ElementInfo { VJustify = VJustify.Center };   // default
        var merged  = ElementReader.Merge(base_, derived);
        Assert.Equal(VJustify.Top, merged.VJustify);
    }

    /// <summary>
    /// VJustify=Bottom from the derived element wins over a Center base.
    /// </summary>
    [Fact]
    public void Merge_DerivedVJustifyBottom_OverridesBaseCenter()
    {
        var base_   = new ElementInfo { VJustify = VJustify.Center };
        var derived = new ElementInfo { VJustify = VJustify.Bottom };
        var merged  = ElementReader.Merge(base_, derived);
        Assert.Equal(VJustify.Bottom, merged.VJustify);
    }

    // ── FontColor — Merge propagation (Fix B) ────────────────────────────────

    /// <summary>
    /// When the derived element has an explicit (non-null) FontColor, the derived value
    /// wins in Merge — same "non-null derived wins" rule used for FontDid and HJustify.
    /// </summary>
    [Fact]
    public void Merge_DerivedFontColor_OverridesBaseNull()
    {
        var base_   = new ElementInfo { FontColor = null };
        var derived = new ElementInfo { FontColor = new Vector4(1f, 0f, 0f, 1f) };
        var merged  = ElementReader.Merge(base_, derived);
        Assert.Equal(new Vector4(1f, 0f, 0f, 1f), merged.FontColor);
    }

    /// <summary>
    /// When the derived element has no FontColor (null), the base's FontColor is inherited.
    /// A null-derived must NOT override a non-null base.
    /// </summary>
    [Fact]
    public void Merge_DerivedFontColorNull_InheritsBaseColor()
    {
        var gold = new Vector4(1f, 0.82f, 0.36f, 1f);
        var base_   = new ElementInfo { FontColor = gold };
        var derived = new ElementInfo { FontColor = null };   // default — no dat property
        var merged  = ElementReader.Merge(base_, derived);
        Assert.Equal(gold, merged.FontColor);
    }

    /// <summary>
    /// When neither base nor derived carries a FontColor, the merged result is null.
    /// </summary>
    [Fact]
    public void Merge_BothFontColorNull_MergedIsNull()
    {
        var base_   = new ElementInfo { FontColor = null };
        var derived = new ElementInfo { FontColor = null };
        var merged  = ElementReader.Merge(base_, derived);
        Assert.Null(merged.FontColor);
    }
}