using AcDream.App.UI;
using AcDream.App.UI.Layout;

namespace AcDream.App.Tests.UI.Layout;

/// <summary>
/// Golden conformance tests for the vitals LayoutDesc importer.
/// Uses the committed JSON fixture (<c>vitals_2100006C.json</c>) — no dats, no GL.
///
/// These tests lock the importer's tree-building (factory dispatch, meter slice
/// extraction, rects) against the real portal.dat values captured when the
/// fixture was generated. Any regression in <see cref="LayoutImporter"/>,
/// <see cref="DatWidgetFactory"/>, or <see cref="ElementReader"/> will surface here.
///
/// Sprite ids sourced from <c>docs/research/2026-06-15-layoutdesc-format.md §11</c>.
/// </summary>
[Trait("Category", "Conformance")]
public class LayoutConformanceTests
{
    // ── Test 1: Three meters at expected rects ────────────────────────────────

    /// <summary>
    /// The three vital bars must be UiMeters positioned at x=5, width=150, height=16,
    /// at y=5 (health), y=21 (stamina), y=37 (mana).
    /// </summary>
    [Fact]
    public void VitalsTree_HasThreeMetersAtExpectedRects()
    {
        var layout = FixtureLoader.LoadVitals();

        (uint Id, float Y)[] expected =
        [
            (0x100000E6u, 5f),   // health
            (0x100000ECu, 21f),  // stamina
            (0x100000EEu, 37f),  // mana
        ];

        foreach (var (id, y) in expected)
        {
            var elem = layout.FindElement(id);
            Assert.NotNull(elem);
            var meter = Assert.IsType<UiMeter>(elem);
            Assert.Equal(5f,   meter.Left);
            Assert.Equal(y,    meter.Top);
            Assert.Equal(150f, meter.Width);
            Assert.Equal(16f,  meter.Height);
        }
    }

    // ── Test 2: All 18 slice ids ──────────────────────────────────────────────

    /// <summary>
    /// The six back+front 3-slice sprite ids for each of the three meters must
    /// match the values confirmed from the dat dump (format doc §11).
    /// This proves the factory's grandchild slice extraction against committed data.
    /// </summary>
    [Fact]
    public void VitalsTree_MetersHaveExpectedSliceIds()
    {
        var layout = FixtureLoader.LoadVitals();

        // Columns: MeterId, then 6 slice ids in order:
        //   BackLeft, BackTile, BackRight, FrontLeft, FrontTile, FrontRight
        (uint MeterId, uint[] Slices)[] cases =
        [
            (0x100000E6u, [0x0600747Eu, 0x0600747Fu, 0x06007480u, 0x06007481u, 0x06007482u, 0x06007483u]), // health
            (0x100000ECu, [0x06007484u, 0x06007485u, 0x06007486u, 0x06007487u, 0x06007488u, 0x06007489u]), // stamina
            (0x100000EEu, [0x0600748Au, 0x0600748Bu, 0x0600748Cu, 0x0600748Du, 0x0600748Eu, 0x0600748Fu]), // mana
        ];

        foreach (var (meterId, s) in cases)
        {
            var m = Assert.IsType<UiMeter>(layout.FindElement(meterId));
            Assert.Equal(s[0], m.BackLeft);   Assert.Equal(s[1], m.BackTile);   Assert.Equal(s[2], m.BackRight);
            Assert.Equal(s[3], m.FrontLeft);  Assert.Equal(s[4], m.FrontTile);  Assert.Equal(s[5], m.FrontRight);
        }
    }

    // ── Test 3: Chrome TL corner type ────────────────────────────────────────
    //
    // NOTE: As of Task 6 (widget-generalization), Type-3 elements are built as
    // UiField (UIElement_Field, reg :126190) rather than UiDatElement. The
    // chrome corner (0x10000633) is a Type-3 dat element and is now a UiField.
    // Its dat sprite (0x060074C3) is not rendered by UiField — UiField renders
    // the focused/unfocused field background only. The sprite rendering for
    // Type-3 chrome image elements is a known limitation; tracked for post-Task-8
    // follow-up (UiField could expose a BackgroundSprite similar to UiText).

    /// <summary>
    /// The top-left chrome corner element (id <c>0x10000633</c>) is Type-3 in
    /// the dat, built as a <see cref="UiField"/> since Task 6. Confirms the
    /// element exists in the tree.
    /// </summary>
    [Fact]
    public void VitalsTree_ChromeCornerHasExpectedSprite()
    {
        var layout = FixtureLoader.LoadVitals();

        var elem = layout.FindElement(0x10000633u);
        Assert.NotNull(elem);
        // Type-3 elements are now built as UiField (UIElement_Field, Task 6).
        Assert.IsType<UiField>(elem);
    }

    // ── Test 4 (N4): Inheritance resolution — FontDid propagated from base ───

    /// <summary>
    /// Proves that <c>Resolve()</c>'s inheritance merge fired against real dat data:
    /// at least one element in the fixture tree must have <c>FontDid == 0x40000000</c>
    /// (the vitals font), inherited from the base-layout prototype <c>0x10000376</c>
    /// in <c>0x2100003F</c> via the <c>BaseElement</c> / <c>BaseLayoutId</c> chain.
    ///
    /// <para>
    /// The three text labels (<c>0x100000EB</c> health, <c>0x100000ED</c> stamina,
    /// <c>0x100000EF</c> mana) are Type=0 derived elements with no own font property.
    /// The base element <c>0x10000376</c> carries <c>Properties[0x1A]</c> →
    /// <c>ArrayBaseProperty[ DataIdBaseProperty{Value=0x40000000} ]</c>.
    /// <see cref="ElementReader.Merge"/> propagates this via the "FontDid: derived wins
    /// if non-zero, otherwise inherit" rule.
    /// </para>
    ///
    /// <para>
    /// This test verifies end-to-end inheritance resolution against the committed fixture
    /// (format doc §10, <c>docs/research/2026-06-15-layoutdesc-format.md</c>).
    /// It operates on the raw <see cref="ElementInfo"/> tree, NOT the widget tree,
    /// so the factory dispatch (Type 12 → skip) does not interfere.
    /// </para>
    /// </summary>
    [Fact]
    public void VitalsTree_TextLabel_InheritsFontDidFromBaseLayout()
    {
        var root = FixtureLoader.LoadVitalsInfos();

        // Walk the full ElementInfo tree and collect all FontDid values.
        var fontDids = new System.Collections.Generic.List<uint>();
        CollectFontDids(root, fontDids);

        // At least one element must carry FontDid == 0x40000000 (the vitals font).
        // In practice, the three text labels (health/stamina/mana) all inherit it.
        Assert.Contains(0x40000000u, fontDids);
    }

    private static void CollectFontDids(ElementInfo node, System.Collections.Generic.List<uint> acc)
    {
        if (node.FontDid != 0) acc.Add(node.FontDid);
        foreach (var child in node.Children)
            CollectFontDids(child, acc);
    }

    // ── Test 5: Horizontal resize conformance (160→200) ──────────────────────

    /// <summary>
    /// Proves end-to-end reflow for a 160→200 width change using the corrected
    /// ToAnchors mapping (UIElement::UpdateForParentSizeChange @0x00462640).
    ///
    /// For each piece, margins are computed from the 160-wide design rect and then
    /// <see cref="UiElement.ComputeAnchoredRect"/> is applied at parentW=200.
    ///
    /// Expected outcomes:
    /// - TL corner (L=1,R=2): Left only → fixed at x=0, w=5
    /// - top edge  (L=1,R=1): Left+Right → stretches to w=190 at x=5
    /// - TR corner (L=2,R=1): Right only → tracks right at x=195, w=5
    /// - meter     (L=1,R=1): Left+Right → stretches to w=190 at x=5
    /// </summary>
    [Fact]
    public void HorizontalResize_160to200_ReflowsCorrectly()
    {
        const float designParentW = 160f;
        const float newParentW    = 200f;
        const float parentH       = 58f;

        // (piece, designX, designW, LeftEdge, RightEdge, expectedX, expectedW)
        (string Piece, float DesignX, float DesignW, uint L, uint R, float ExpX, float ExpW)[] cases =
        [
            ("TL corner", 0f,   5f,   1u, 2u, 0f,   5f  ),
            ("top edge",  5f,   150f, 1u, 1u, 5f,   190f),
            ("TR corner", 155f, 5f,   2u, 1u, 195f, 5f  ),
            ("meter",     5f,   150f, 1u, 1u, 5f,   190f),
        ];

        foreach (var (piece, dX, dW, l, r, expX, expW) in cases)
        {
            // T/B values don't affect x/w; use real vitals values (top=1, bottom=2)
            var anchors = ElementReader.ToAnchors(l, top: 1u, r, bottom: 2u);

            // Margins from the design rect at parentW=160
            float mL = dX;
            float mR = designParentW - (dX + dW);

            // Reflow at parentW=200 (parentH irrelevant for x/w assertions)
            var (x, _, w, _) = UiElement.ComputeAnchoredRect(
                anchors, mL, mT: 0f, mR, mB: 0f, w0: dW, h0: 5f, parentW: newParentW, parentH);

            // xUnit 2.x Assert.Equal(float,float,int) = decimal-place precision
            Assert.True(Math.Abs(x - expX) < 0.5f, $"{piece}: expected x={expX} got {x}");
            Assert.True(Math.Abs(w - expW) < 0.5f, $"{piece}: expected w={expW} got {w}");
        }
    }
}