using Godot;

public partial class CorruptionArea : Node3D
{
    public override void _Ready()
    {
        _disc = GetNode<MeshInstance3D>("Disc");
        if (_disc == null)
        {
            GD.PushWarning("CorruptionArea: Could not find child MeshInstance3D named 'Disc'.");
            return;
        }

        _baseScale = _disc.Scale;
        ApplyRadius();

        _shaderMaterial = (ShaderMaterial)_disc.GetActiveMaterial(0).Duplicate();
        _disc.MaterialOverride = _shaderMaterial;
    }

    public override void _Process(double delta)
    {
        if (_shaderMaterial == null)
            return;

        var t = Time.GetTicksMsec() / 1000.0f;
        var pulse = 1.0f + Mathf.Sin(t * PulseSpeed) * PulseAmount;

        _shaderMaterial.SetShaderParameter("u_pulse", pulse);
        _shaderMaterial.SetShaderParameter("base_color", Color);
    }

    /// <summary>
    ///     Call this if you change Radius at runtime.
    /// </summary>
    public void ApplyRadius()
    {
        if (_disc == null)
            return;

        var r = Mathf.Max(Radius, 0.01f);
        // PlaneMesh is 2x2 units, so scale XZ by radius to get the desired world radius.
        _disc.Scale = new(_baseScale.X * r, _baseScale.Y, _baseScale.Z * r);
    }

    public void SetRadius(float radius)
    {
        Radius = radius;
        ApplyRadius();
    }

    [Export]
    public float Radius { get; set; } = 1.0f; // World-space radius in XZ units.

    [Export]
    public float PulseSpeed { get; set; } = 1.5f;

    [Export]
    public float PulseAmount { get; set; } = 0.25f;

    [Export]
    public Color Color { get; set; } = new(0.6f, 0.1f, 0.8f, 0.45f);

    private Vector3 _baseScale = Vector3.One;

    private MeshInstance3D _disc;
    private ShaderMaterial _shaderMaterial;
}