using Godot;

// The in-VR menu: a MenuScreen (Godot Control UI in a SubViewport on a thin 0.36x0.24 m
// panel) showing MainMenu. This node is the XR glue: summon/dismiss with the LEFT ax_button (X; right A is jump),
// grip-drag (direct or along the laser), re-orient toward the head, feed both controllers'
// pointer rays into the screen, click sound + haptics. PARENTED UNDER XROrigin3D (fixed in the
// player's room; game locomotion carries it).
public partial class WorldPanel : Node3D
{
    private const float GripThreshold = 0.6f;
    private const float TriggerThreshold = 0.6f;
    private const float DirectGrabRadius = 0.45f;
    private const float SummonDistance = 0.3f;
    private const float HeadRecallDistance = 0.45f;
    private const float HeadRecallDrop = 0.12f;

    private static WorldPanel _instance;

    private XRController3D _left;
    private XRController3D _right;
    private XRCamera3D _camera;
    private Locomotion _locomotion;
    private PropShop _propShop;
    private AudioStreamPlayer3D _click;
    private AudioStreamPlayer3D _ping;

    private MenuScreen _screen;
    private MainMenu _menu;

    private readonly bool[] _dragging = new bool[2];
    private readonly bool[] _directDrag = new bool[2];
    private readonly float[] _laserDist = new float[2];
    private readonly Vector3[] _directOffset = new Vector3[2];
    private readonly bool[] _summonPrev = new bool[2];
    private readonly MenuScreen.PointerInput[] _inputs = new MenuScreen.PointerInput[2];

    public override void _Ready()
    {
        _instance = this;
        _left = GetNode<XRController3D>("../LeftHand");
        _right = GetNode<XRController3D>("../RightHand");
        _camera = GetNode<XRCamera3D>("../XRCamera3D");
        _locomotion = GetNode<Locomotion>("../../Locomotion");
        _propShop = GetNode<PropShop>("../../PropShop");

        _screen = new MenuScreen { Name = "Screen" };
        AddChild(_screen);
        _menu = new MainMenu { Name = "MainMenu" };
        _screen.SetContent(_menu);
        _screen.PointerPressed += OnPointerPressed;
        _screen.Haptic += (hand, amplitude, seconds) =>
            (hand == 0 ? _left : _right).TriggerHapticPulse("haptic", 0.0, amplitude, seconds, 0.0);

        _menu.ReturnToSpawnRequested += () =>
        {
            _locomotion.ReturnToSpawn();
            ResetInteractionState();
            PlaceInFrontOfHead();
            _menu.Log("Returned to spawn");
        };
        _menu.ResetPropsRequested += () =>
        {
            _propShop.Respawn();
            GetNodeOrNull<Playground>("../../Playground")?.Reset();
            GetNodeOrNull<Crag>("../../Crag")?.Reset();
            _menu.Log("Props reset");
        };
        _menu.PingRequested += () =>
        {
            GD.Print("WorldPanel: ping");
            _ping.Play();
            _menu.Log("Ping");
        };
        _menu.CloseRequested += () => SetPanelActive(false);
        _menu.Clicked += () => _click.Play();

        _click = MakeTone(900f, 25, 0.35f, 1f);
        _ping = MakeTone(1320f, 4, 0.3f, 3f);
        _menu.ClickVolumeSlider.ValueChanged += v => _click.VolumeDb = Mathf.LinearToDb((float)v / 70f);
        _menu.StrengthChanged += v => PlayerRagdoll.Strength = v;
        _menu.SmoothTurnToggled += on => PlayerRig.SmoothTurn = on;
        _menu.SpectatorToggled += PlayerRig.SetSpectator;

        SetPanelActive(false);
    }

    // This controller currently points at (or touches) the menu — its stick scrolls the menu,
    // so locomotion must ignore it.
    public static bool IsPointing(XRController3D controller)
    {
        if (_instance == null || !_instance.Visible)
            return false;
        int hand = controller == _instance._left ? 0 : controller == _instance._right ? 1 : -1;
        return hand >= 0 && _instance._screen.GetMode(hand) != MenuScreen.PointerMode.None;
    }

    public static bool IsBlocking(XRController3D controller) =>
        _instance != null && _instance.Visible &&
        _instance.GlobalPosition.DistanceTo(controller.GlobalPosition) < DirectGrabRadius;

    public static bool IsPanelCollider(Node node) =>
        _instance != null && _instance.Visible && node != null &&
        (node == _instance._screen.Body || node.GetParent() == _instance._screen.Body);

    // Laser length to the menu for this controller, if the controller is currently using its
    // laser (not touch) on the menu. Locomotion.UpdatePointer draws the beam from this.
    public static bool TryGetLaserDistance(XRController3D controller, out float distance)
    {
        distance = 0f;
        if (_instance == null || !_instance.Visible)
            return false;
        int hand = controller == _instance._left ? 0 : controller == _instance._right ? 1 : -1;
        return hand >= 0 && _instance._screen.TryGetLaserDistance(hand, out distance);
    }

    public override void _Process(double delta)
    {
        PollSummon(_left, 0);   // left X only: right A is jump
        if (Visible)
        {
            UpdateDrag(_left, 0);
            UpdateDrag(_right, 1);
        }
        _inputs[0] = ReadPointer(_left, 0);
        _inputs[1] = ReadPointer(_right, 1);
        _screen.UpdatePointers(_inputs, delta);
    }

    private MenuScreen.PointerInput ReadPointer(XRController3D controller, int hand) => new()
    {
        // A hand dragging the panel doesn't also point at it.
        Valid = !_dragging[hand] && controller.GetIsActive(),
        Origin = controller.GlobalPosition,
        Direction = -controller.GlobalTransform.Basis.Z,
        Trigger = controller.GetFloat("trigger") > TriggerThreshold,
        Stick = controller.GetVector2("primary"),
    };

    private void OnPointerPressed(int hand, MenuScreen.PointerMode mode)
    {
        XRController3D controller = hand == 0 ? _left : _right;
        // Short tick on contact: the "physical press" feel for the touch cursor.
        controller.TriggerHapticPulse("haptic", 0.0, mode == MenuScreen.PointerMode.Touch ? 0.35 : 0.2, 0.02, 0.0);
    }

    private void PollSummon(XRController3D controller, int hand)
    {
        bool summon = controller.IsButtonPressed("ax_button");
        if (summon && !_summonPrev[hand])
        {
            if (!Visible)
                PlaceInFrontOf(controller);
            SetPanelActive(!Visible);
            GD.Print($"WorldPanel: {(Visible ? "summoned" : "dismissed")} via ax_button ({(hand == 0 ? "left" : "right")})");
        }
        _summonPrev[hand] = summon;
    }

    private void SetPanelActive(bool active)
    {
        ResetInteractionState();
        Visible = active;
        _screen.SetActive(active);
        if (active)
            _menu.RefreshCalibration();
    }

    private void PlaceInFrontOf(XRController3D controller) =>
        OrientTo(controller.GlobalPosition - controller.GlobalTransform.Basis.Z * SummonDistance);

    private void PlaceInFrontOfHead()
    {
        Vector3 forward = -_camera.GlobalTransform.Basis.Z;
        forward.Y = 0f;
        forward = forward.LengthSquared() < 0.0001f ? Vector3.Forward : forward.Normalized();
        OrientTo(_camera.GlobalPosition + forward * HeadRecallDistance + Vector3.Down * HeadRecallDrop);
    }

    private static Basis FacingBasis(Vector3 from, Vector3 head, out bool ok)
    {
        ok = false;
        Vector3 look = head - from;
        if (look.LengthSquared() < 0.0001f)
            return Basis.Identity;
        Vector3 zAxis = look.Normalized();
        Vector3 xAxis = Vector3.Up.Cross(zAxis);
        if (xAxis.LengthSquared() < 0.0001f)
            return Basis.Identity;
        xAxis = xAxis.Normalized();
        Vector3 yAxis = zAxis.Cross(xAxis).Normalized();
        ok = true;
        return new Basis(xAxis, yAxis, zAxis);
    }

    private void OrientTo(Vector3 pos)
    {
        Basis basis = FacingBasis(pos, _camera.GlobalPosition, out bool ok);
        if (ok)
            GlobalTransform = new Transform3D(basis, pos);
    }

    private void OrientTowardCamera()
    {
        Basis basis = FacingBasis(GlobalPosition, _camera.GlobalPosition, out bool ok);
        if (ok)
            GlobalBasis = GlobalBasis.Slerp(basis, 0.35f).Orthonormalized();
    }

    private AudioStreamPlayer3D MakeTone(float frequency, int durationDivisor, float amplitude, float decayPower)
    {
        const int rate = 44100;
        int samples = rate / durationDivisor;
        byte[] data = new byte[samples * 2];
        for (int i = 0; i < samples; i++)
        {
            float envelope = Mathf.Pow(1f - (float)i / samples, decayPower);
            float value = Mathf.Sin(Mathf.Tau * frequency * i / rate) * envelope * amplitude;
            short sample = (short)(value * short.MaxValue);
            data[i * 2] = (byte)sample;
            data[i * 2 + 1] = (byte)(sample >> 8);
        }
        AudioStreamPlayer3D player = new()
        {
            Stream = new AudioStreamWav
            {
                Format = AudioStreamWav.FormatEnum.Format16Bits,
                MixRate = rate,
                Stereo = false,
                Data = data,
            },
        };
        AddChild(player);
        return player;
    }

    private void UpdateDrag(XRController3D controller, int hand)
    {
        Vector3 from = controller.GlobalPosition;
        Vector3 dir = -controller.GlobalTransform.Basis.Z;
        bool laserOnPanel = _screen.GetMode(hand) == MenuScreen.PointerMode.Laser;

        bool grip = controller.GetFloat("grip") > GripThreshold
            && !PropGrabber.IsGrabbing(controller);
        if (grip && !_dragging[hand] && (laserOnPanel || GlobalPosition.DistanceTo(from) < DirectGrabRadius))
        {
            _dragging[hand] = true;
            _directDrag[hand] = !laserOnPanel;
            if (_directDrag[hand])
                _directOffset[hand] = GlobalPosition - from;
            else
                _laserDist[hand] = Mathf.Max(0.2f, (GlobalPosition - from).Dot(dir));
            GD.Print($"WorldPanel: grab started ({(_directDrag[hand] ? "direct" : "laser")}, {(hand == 0 ? "left" : "right")})");
        }
        if (!grip && _dragging[hand])
        {
            _dragging[hand] = false;
            GD.Print("WorldPanel: grab released");
        }

        if (_dragging[hand])
        {
            GlobalPosition = _directDrag[hand]
                ? from + _directOffset[hand]
                : from + dir * _laserDist[hand];
            OrientTowardCamera();
        }
    }

    private void ResetInteractionState()
    {
        for (int hand = 0; hand < 2; hand++)
            _dragging[hand] = false;
        _screen?.ReleaseAll();
    }
}