using Godot;
using System;
using System.Threading.Tasks;

// Headless regression for the in-VR menu (MenuScreen + MainMenu), no XR: drives simulated
// controller rays at known controls and asserts the Godot UI reacted. Run:
//   godot-mono --headless --fixed-fps 90 --path . scenes/menu_spike.tscn
// Must print "MENU: overall PASS".
public partial class MenuSpike : Node3D
{
    private partial class CalibrationStub : Node
    {
        public int Calls;
        public void Recalibrate() => Calls++;
    }

    private MenuScreen _screen;
    private MainMenu _menu;
    private readonly MenuScreen.PointerInput[] _inputs = new MenuScreen.PointerInput[2];
    private int _spawn, _reset, _ping, _close, _clicks, _pressedEvents, _hapticTicks;
    private bool _allPass = true;

    public override void _Ready()
    {
        _screen = new MenuScreen();
        AddChild(_screen);
        // Arbitrary, non-axis-aligned pose to exercise the plane math.
        _screen.GlobalTransform = new Transform3D(
            Basis.FromEuler(new Vector3(Mathf.DegToRad(-15f), Mathf.DegToRad(30f), 0f)),
            new Vector3(0.3f, 1.3f, -0.5f));
        _menu = new MainMenu();
        _screen.SetContent(_menu);
        _screen.SetActive(true);
        _screen.PointerPressed += (_, _) => _pressedEvents++;
        _screen.Haptic += (_, _, _) => _hapticTicks++;
        _menu.ReturnToSpawnRequested += () => _spawn++;
        _menu.ResetPropsRequested += () => _reset++;
        _menu.PingRequested += () => _ping++;
        _menu.CloseRequested += () => _close++;
        _menu.Clicked += () => _clicks++;
        GetTree().CreateTimer(30.0).Timeout += () =>
        {
            GD.Print("MENU: timeout — overall FAIL");
            GetTree().Quit(1);
        };
        Run();
    }

    private void Check(string name, bool ok, string detail = "")
    {
        GD.Print($"MENU: {name} {detail} → {(ok ? "PASS" : "FAIL")}");
        _allPass &= ok;
    }

    private async Task Frame(int count = 1)
    {
        for (int i = 0; i < count; i++)
        {
            _screen.UpdatePointers(_inputs, 1.0 / 90.0);
            await ToSignal(GetTree(), SceneTree.SignalName.ProcessFrame);
        }
    }

    private Vector2 Center(Control c) => c.GetGlobalRect().GetCenter();
    private Vector3 Normal => _screen.GlobalBasis.Z.Normalized();

    private void SetHand(int hand, Vector3 origin, Vector3 dir, bool trigger = false, Vector2 stick = default) =>
        _inputs[hand] = new MenuScreen.PointerInput { Valid = true, Origin = origin, Direction = dir.Normalized(), Trigger = trigger, Stick = stick };

    private void ClearHand(int hand) => _inputs[hand] = default;

    // Stylus straight at the panel: tip depth d in front of the pixel (negative = pushed through).
    private void TipAt(int hand, Vector2 pixel, float depth)
    {
        Vector3 p = _screen.PixelToGlobal(pixel);
        SetHand(hand, p + Normal * (MenuScreen.TipLength + depth), -Normal);
    }

    private async Task TouchPress(int hand, Vector2 pixel)
    {
        for (float d = 0.10f; d > -0.012f; d -= 0.004f)
        {
            TipAt(hand, pixel, d);
            await Frame();
        }
        for (float d = -0.012f; d < 0.08f; d += 0.006f)
        {
            TipAt(hand, pixel, d);
            await Frame();
        }
        ClearHand(hand);
        await Frame(3);
    }

    // Touch down at `from`, slide to `to` while in contact, lift. fling = a fast 4-frame slide.
    private async Task TouchDrag(int hand, Vector2 from, Vector2 to, bool fling = false)
    {
        for (float d = 0.06f; d > -0.004f; d -= 0.004f)
        {
            TipAt(hand, from, d);
            await Frame();
        }
        // A fling lifts while still moving (as a real flick does); a slow drag stops, then lifts.
        int steps = fling ? 8 : 30;
        for (int i = 1; i <= steps; i++)
        {
            float lift = fling ? Mathf.Max(0f, i - 4) * 0.008f : 0f;
            TipAt(hand, from.Lerp(to, i / (float)steps), -0.004f + lift);
            await Frame();
        }
        float start = fling ? -0.004f + (steps - 4) * 0.008f : -0.004f;
        for (float d = start; d < 0.08f; d += 0.006f)
        {
            TipAt(hand, to, d);
            await Frame();
        }
        ClearHand(hand);
        await Frame(3);
    }

    // Laser from 0.8 m, off-axis, aimed at the pixel.
    private void LaserAt(int hand, Vector2 pixel, bool trigger, Vector2 stick = default)
    {
        Vector3 p = _screen.PixelToGlobal(pixel);
        Vector3 origin = p + Normal * 0.7f + _screen.GlobalBasis.X * 0.25f + Vector3.Up * 0.2f;
        SetHand(hand, origin, p - origin, trigger, stick);
    }

    private async Task LaserClick(int hand, Vector2 pixel)
    {
        LaserAt(hand, pixel, false);
        await Frame(4);
        LaserAt(hand, pixel, true);
        await Frame(4);
        LaserAt(hand, pixel, false);
        await Frame(4);
        ClearHand(hand);
        await Frame(3);
    }

    private Vector2 TabCenter(int index)
    {
        TabBar bar = _menu.Tabs.GetTabBar();
        Rect2 r = bar.GetTabRect(index);
        return bar.GetGlobalRect().Position + r.GetCenter();
    }

    private async void Run()
    {
        await Frame(10); // layout

        // Mapping sanity: pixel → world → local → pixel round trip.
        Vector2 probe = new(123f, 456f);
        Vector2 back = _screen.LocalToPixel(_screen.GlobalTransform.AffineInverse() * _screen.PixelToGlobal(probe));
        Check("pixel mapping round trip", back.DistanceTo(probe) < 0.01f, $"({back})");

        // 1) Touch path, with the other hand idling as a laser on the panel (arbitration:
        //    touch beats laser).
        Vector2 spawnPx = Center(_menu.ReturnToSpawnButton);
        LaserAt(0, new Vector2(800, 600), false);
        await Frame(3);
        Check("idle laser is laser mode", _screen.GetMode(0) == MenuScreen.PointerMode.Laser);
        bool sawHover = false, sawTouch = false;
        for (float d = 0.10f; d > -0.012f; d -= 0.004f)
        {
            TipAt(1, spawnPx, d);
            await Frame();
            sawTouch |= _screen.GetMode(1) == MenuScreen.PointerMode.Touch;
            sawHover |= _menu.ReturnToSpawnButton.IsHovered();
        }
        bool pressedWhileIn = _screen.IsPressing(1);
        for (float d = -0.012f; d < 0.08f; d += 0.006f)
        {
            TipAt(1, spawnPx, d);
            await Frame();
        }
        ClearHand(0);
        ClearHand(1);
        await Frame(3);
        Check("touch: tip mode + hover", sawTouch && sawHover, $"(touch={sawTouch}, hover={sawHover})");
        Check("touch: contact holds press", pressedWhileIn);
        Check("touch: Return to spawn fired once", _spawn == 1, $"(count={_spawn}, pressedEvents={_pressedEvents})");

        // 2) Tip sweeping in sideways already behind the surface must NOT press.
        int before = _spawn;
        Vector2 offPanel = new(-60f, spawnPx.Y);
        for (int i = 0; i <= 30; i++)
        {
            Vector2 px = offPanel.Lerp(spawnPx, i / 30f);
            Vector3 p = _screen.GlobalTransform * new Vector3(
                (px.X / _screen.SizePixels.X - 0.5f) * _screen.SizeMeters.X,
                (0.5f - px.Y / _screen.SizePixels.Y) * _screen.SizeMeters.Y, 0f);
            SetHand(1, p + Normal * (MenuScreen.TipLength - 0.01f), -Normal);
            await Frame();
        }
        TipAt(1, spawnPx, 0.08f);
        await Frame(3);
        ClearHand(1);
        await Frame(3);
        Check("touch: side entry behind surface does not press", _spawn == before, $"(count={_spawn})");

        // 3) Laser + trigger: switch to the World tab, then Reset props.
        await LaserClick(0, TabCenter(1));
        Check("laser: World tab selected", _menu.Tabs.CurrentTab == 1, $"(tab={_menu.Tabs.CurrentTab})");
        await Frame(2);
        Vector2 resetPx = Center(_menu.ResetPropsButton);
        LaserAt(0, resetPx, false);
        await Frame(2);
        bool laserDist = _screen.TryGetLaserDistance(0, out float dist) && dist > 0.5f && dist < 1.0f;
        Check("laser: distance reported", laserDist, $"({dist:F3} m)");
        await LaserClick(0, resetPx);
        Check("laser: Reset props fired once", _reset == 1, $"(count={_reset})");

        // 4) Trigger already held when the laser arrives must not click.
        LaserAt(0, new Vector2(-200, -200), true); // off panel
        await Frame(3);
        LaserAt(0, Center(_menu.PingButton), true);
        await Frame(5);
        LaserAt(0, Center(_menu.PingButton), false);
        await Frame(3);
        ClearHand(0);
        await Frame(2);
        Check("laser: held trigger arriving does not click", _ping == 0, $"(count={_ping})");
        await LaserClick(0, Center(_menu.PingButton));
        Check("laser: Ping fired once", _ping == 1, $"(count={_ping})");

        // 5) Touch a tab, then drag the slider with the laser (trigger held).
        await TouchPress(1, TabCenter(2));
        Check("touch: System tab selected", _menu.Tabs.CurrentTab == 2, $"(tab={_menu.Tabs.CurrentTab})");
        await Frame(2);
        Rect2 sr = _menu.ClickVolumeSlider.GetGlobalRect();
        double v0 = _menu.ClickVolumeSlider.Value;
        Vector2 grab = new(sr.Position.X + sr.Size.X * (float)(v0 / 100.0), sr.GetCenter().Y);
        LaserAt(0, grab, false);
        await Frame(3);
        LaserAt(0, grab, true);
        await Frame(3);
        for (int i = 1; i <= 20; i++)
        {
            LaserAt(0, grab.Lerp(new Vector2(sr.Position.X + 4f, grab.Y), i / 20f), true);
            await Frame();
        }
        LaserAt(0, new Vector2(sr.Position.X + 4f, grab.Y), false);
        await Frame(3);
        ClearHand(0);
        await Frame(2);
        double v1 = _menu.ClickVolumeSlider.Value;
        Check("laser: slider drag", v1 < v0 - 30, $"({v0} → {v1})");

        // 6) Thumbstick scrolls the log while hovering it.
        for (int i = 0; i < 60; i++)
            _menu.Log($"log line {i}");
        await Frame(5);
        Vector2 logPx = Center(_menu.LogScroll);
        LaserAt(0, logPx, false, new Vector2(0, -1));
        await Frame(30);
        int scrolled = _menu.LogScroll.ScrollVertical;
        LaserAt(0, logPx, false, new Vector2(0, 1));
        await Frame(60);
        int scrolledBack = _menu.LogScroll.ScrollVertical;
        ClearHand(0);
        await Frame(2);
        Check("stick: scroll down then up", scrolled > 50 && scrolledBack < scrolled, $"({scrolled} → {scrolledBack})");

        // 6b) Touch swipe vs tap inside the scrollable log.
        Button logButton = new() { Text = "in-log button", CustomMinimumSize = new Vector2(0, 48) };
        int logButtonPresses = 0;
        logButton.Pressed += () => logButtonPresses++;
        _menu.LogScroll.GetChild(0).AddChild(logButton);
        _menu.LogScroll.GetChild(0).MoveChild(logButton, 0);
        _menu.LogScroll.ScrollVertical = 0;
        await Frame(5);
        int clicksBefore = _clicks;
        await TouchDrag(1, logPx, logPx + new Vector2(0, -150));
        int swiped = _menu.LogScroll.ScrollVertical;
        Check("touch: swipe up scrolls the log", swiped >= 120, $"(scroll 0 → {swiped})");
        Check("touch: swipe sends no click", _clicks == clicksBefore && logButtonPresses == 0, $"(clicks +{_clicks - clicksBefore})");
        await TouchDrag(1, logPx, logPx + new Vector2(0, 80), fling: true);
        await Frame(60);
        int flung = _menu.LogScroll.ScrollVertical;
        Check("touch: fast swipe down flings past the finger", flung < swiped - 60, $"({swiped} → {flung})");
        _menu.LogScroll.ScrollVertical = 0;
        await Frame(5);
        Vector2 btnPx = Center(logButton);
        await TouchDrag(1, btnPx, btnPx + new Vector2(6, 5));
        Check("touch: small-jitter tap on in-log button clicks", logButtonPresses == 1 && _menu.LogScroll.ScrollVertical == 0,
            $"(presses={logButtonPresses}, scroll={_menu.LogScroll.ScrollVertical})");
        VScrollBar vbar = _menu.LogScroll.GetVScrollBar();
        Rect2 br = vbar.GetGlobalRect();
        await TouchDrag(1, new Vector2(br.GetCenter().X, br.Position.Y + 10), new Vector2(br.GetCenter().X, br.End.Y - 10));
        Check("touch: scrollbar still drags directly", _menu.LogScroll.ScrollVertical > 100, $"(scroll={_menu.LogScroll.ScrollVertical})");

        // 7) Recalibrate: disabled without a calibration node, enabled + calls it when present.
        await TouchPress(1, TabCenter(0));
        Check("Recalibrate disabled without group node", _menu.RecalibrateButton.Disabled);
        await TouchPress(1, Center(_menu.RecalibrateButton));
        CalibrationStub stub = new();
        AddChild(stub);
        stub.AddToGroup(MainMenu.CalibrationGroup);
        await Frame(40); // refresh runs at 4 Hz
        Check("Recalibrate enabled with group node", !_menu.RecalibrateButton.Disabled);
        await TouchPress(1, Center(_menu.RecalibrateButton));
        Check("touch: Recalibrate called once", stub.Calls == 1, $"(calls={stub.Calls})");

        // 8) Header Close via touch.
        await TouchPress(1, Center(_menu.HeaderCloseButton));
        Check("touch: Close fired once", _close == 1, $"(count={_close})");
        Check("click feedback fired", _clicks >= 8, $"(clicks={_clicks})");
        Check("haptic ticks fired (hover/release/detents)", _hapticTicks >= 30, $"(ticks={_hapticTicks})");

        GD.Print($"MENU: overall {(_allPass ? "PASS" : "FAIL")}");
        GetTree().Quit(_allPass ? 0 : 1);
    }
}