using Godot;
using System;

[Tool]
public partial class ProgCircle : MeshInstance3D
{
    [Export]
    public int Segments { get; set; } = 64;

    [Export]
    public float Progress { get; set; } = 0f;

    [Export]
    public float Thickness { get; set; } = 0.1f;

    [Export]
    public float Radius { get; set; } = 1f;

    [Export]
    public Color RingColor { get; set; } = Colors.White;

    private ArrayMesh meshData = new ArrayMesh();

    public override void _Ready()
    {
        UpdateRing();
    }

    public override void _Process(double delta)
    {
        UpdateRing(); // optional, remove if static
    }

    public void UpdateRing()
    {
        int vertexCount = (Segments + 1) * 2;
        var vertices = new Vector3[vertexCount];
        var colors = new Color[vertexCount];
        var indices = new int[Segments * 6];

        for (int i = 0; i <= Segments; i++)
        {
            float t = (float)i / Segments * Progress;
            float angle = t * Mathf.Tau;
            float cos = Mathf.Cos(angle);
            float sin = Mathf.Sin(angle);

            Color linearColor = RingColor.SrgbToLinear();

            // Outer vertex
            vertices[i * 2] = new Vector3(cos * Radius, sin * Radius, 0);
            colors[i * 2] = linearColor;

            // Inner vertex
            vertices[i * 2 + 1] = new Vector3(cos * (Radius - Thickness), sin * (Radius - Thickness), 0);
            colors[i * 2 + 1] = linearColor;

            if (i > 0)
            {
                int baseIndex = (i - 1) * 6;
                int vBase = (i - 1) * 2;

                // First triangle
                indices[baseIndex] = vBase;
                indices[baseIndex + 1] = vBase + 1;
                indices[baseIndex + 2] = vBase + 2;

                // Second triangle
                indices[baseIndex + 3] = vBase + 2;
                indices[baseIndex + 4] = vBase + 1;
                indices[baseIndex + 5] = vBase + 3;
            }
        }

        var arrays = new Godot.Collections.Array();
        arrays.Resize((int)Mesh.ArrayType.Max);
        arrays[(int)Mesh.ArrayType.Vertex] = vertices;
        arrays[(int)Mesh.ArrayType.Color] = colors;
        arrays[(int)Mesh.ArrayType.Index] = indices;

        meshData.ClearSurfaces();
        meshData.AddSurfaceFromArrays(Mesh.PrimitiveType.Triangles, arrays);

        // Make sure the material uses vertex colors
        if (MaterialOverride == null)
        {
            var mat = new StandardMaterial3D();
            mat.VertexColorUseAsAlbedo = true;
            mat.ShadingMode = BaseMaterial3D.ShadingModeEnum.Unshaded;
            MaterialOverride = mat;
        }

        Mesh = meshData;
    }
}