using System.Buffers.Binary;
using System.Numerics;
using AcDream.Core.Net.Messages;
using AcDream.Core.Physics;
using Xunit;

namespace AcDream.Core.Net.Tests.Messages;

/// <summary>
/// Pins the shared WorldPosition/Position block byte order used by
/// <see cref="MoveToState"/>, <see cref="AutonomousPosition"/>, and
/// <see cref="JumpAction"/>: <c>Position::Pack</c> (0x005a9640) wraps
/// <c>cellId(u32)</c> then <c>Frame::Pack</c> (0x00535130) =
/// <c>origin.x/y/z(f32)</c> then <c>qw/qx/qy/qz(f32)</c>. Confirmed verbatim
/// against the Ghidra decompile-by-address bridge during this slice
/// (2026-06-30):
///
/// <code>
/// Position::Pack: objcell_id(u32), Frame::Pack(...)
/// Frame::Pack:    m_fOrigin.x/y/z(f32 x3), qw(f32), qx(f32), qy(f32), qz(f32)
/// </code>
///
/// 32 bytes total (4 + 12 + 16). This was already correct pre-slice — these
/// tests lock the byte order with a golden-value assertion rather than
/// changing behavior.
/// </summary>
public class PositionPackTests
{
    [Fact]
    public void MoveToState_PositionBlock_OrderIsCellIdThenOriginThenQuaternion()
    {
        var body = MoveToState.Build(
            gameActionSequence: 1,
            rawMotionState: RawMotionState.Default,
            cellId: 0xA9B40001u,
            position: new Vector3(1.5f, 2.5f, 3.5f),
            rotation: new Quaternion(0.1f, 0.2f, 0.3f, 0.9f), // X,Y,Z,W ctor order
            instanceSequence: 0,
            serverControlSequence: 0,
            teleportSequence: 0,
            forcePositionSequence: 0);

        // No motion state -> flags(4) only before the Position block at offset 16.
        int off = 12 + 4;
        uint cellId = BinaryPrimitives.ReadUInt32LittleEndian(body.AsSpan(off));
        float x = BinaryPrimitives.ReadSingleLittleEndian(body.AsSpan(off + 4));
        float y = BinaryPrimitives.ReadSingleLittleEndian(body.AsSpan(off + 8));
        float z = BinaryPrimitives.ReadSingleLittleEndian(body.AsSpan(off + 12));
        float qw = BinaryPrimitives.ReadSingleLittleEndian(body.AsSpan(off + 16));
        float qx = BinaryPrimitives.ReadSingleLittleEndian(body.AsSpan(off + 20));
        float qy = BinaryPrimitives.ReadSingleLittleEndian(body.AsSpan(off + 24));
        float qz = BinaryPrimitives.ReadSingleLittleEndian(body.AsSpan(off + 28));

        Assert.Equal(0xA9B40001u, cellId);
        Assert.Equal(1.5f, x);
        Assert.Equal(2.5f, y);
        Assert.Equal(3.5f, z);
        Assert.Equal(0.9f, qw);
        Assert.Equal(0.1f, qx);
        Assert.Equal(0.2f, qy);
        Assert.Equal(0.3f, qz);
    }
}