using System;
using System.IO;
using System.Numerics;
using AcDream.Core.Physics;
using Xunit;
using Xunit.Abstractions;

namespace AcDream.Core.Tests.Physics;

// TEMPORARY #347 diagnostic — deleted before landing.
public sealed class Scratch347DiagTests
{
    private readonly ITestOutputHelper _out;
    public Scratch347DiagTests(ITestOutputHelper output) => _out = output;

    [Fact]
    public void DumpFirstArmingTick()
    {
        var heights = new byte[81];
        heights[3 * 9 + 4] = 32;
        var heightTable = new float[256];
        for (int i = 0; i < 256; i++) heightTable[i] = i;

        var engine = new PhysicsEngine();
        engine.AddLandblock(0xA9B4FFFFu, new TerrainSurface(heights, heightTable),
            Array.Empty<CellSurface>(), Array.Empty<PortalPlane>(), 0f, 0f);

        var body = new PhysicsBody
        {
            State = PhysicsStateFlags.Gravity,
            TransientState = TransientStateFlags.Active | TransientStateFlags.Contact | TransientStateFlags.OnWalkable,
        };

        float dx = 0f, dy = 0.23f;
        var position = new Vector3(80.4f, 79.8f, 0f);
        uint cell = TerrainSurface.ComputeOutdoorCellId(0xA9B4FFFFu, 80.4f, 79.8f);

        PhysicsDiagnostics.DumpTransitFailEnabled = true;
        var saved = Console.Out;
        var sw = new StringWriter();
        Console.SetOut(sw);
        try
        {
            for (int tick = 0; tick < 3; tick++)
            {
                var result = engine.ResolveWithTransition(
                    currentPos: position,
                    targetPos: new Vector3(position.X + dx, position.Y + dy, position.Z),
                    cellId: cell,
                    sphereRadius: 0.47f,
                    sphereHeight: 1.20f,
                    stepUpHeight: 0.60f,
                    stepDownHeight: 1.50f,
                    isOnGround: true,
                    body: body,
                    moverFlags: ObjectInfoState.IsPlayer | ObjectInfoState.EdgeSlide,
                    movingEntityId: 0x5000000Au);
                position = result.Position;
                cell = result.CellId;
                if (tick < 2) sw.GetStringBuilder().Clear();  // keep only the arming tick
            }
        }
        finally
        {
            Console.SetOut(saved);
            PhysicsDiagnostics.DumpTransitFailEnabled = false;
        }

        foreach (var line in sw.ToString().Split('\n'))
            _out.WriteLine(line.TrimEnd());
    }
}