using System;
using UnityEngine;
using UnityEngine.Rendering;

namespace CultMath.Unity;

public static class PlanetaryPatchMeshAdapter
{
    public static Mesh CreateFaceMesh(PlanetaryCubeFace face, int cellsPerAxis, float radius = 1)
    {
        if (!float.IsFinite(radius) || radius <= 0) throw new ArgumentOutOfRangeException(nameof(radius));
        var source = PlanetaryPatch.CreateFace(face, cellsPerAxis);
        var vertices = new Vector3[source.Vertices.Length];
        var normals = new Vector3[source.Vertices.Length];
        var uv = new Vector2[source.Vertices.Length];
        for (var i = 0; i < source.Vertices.Length; i++)
        {
            var direction = source.Vertices[i].UnitDirection;
            var normal = new Vector3(direction.x, direction.y, direction.z);
            vertices[i] = normal * radius;
            normals[i] = normal;
            uv[i] = new Vector2(source.Vertices[i].LocalCoordinate.x, source.Vertices[i].LocalCoordinate.y);
        }
        var mesh = new Mesh
        {
            name = $"CultMath Planetary {face} {cellsPerAxis}x{cellsPerAxis}",
            indexFormat = vertices.Length > ushort.MaxValue ? IndexFormat.UInt32 : IndexFormat.UInt16,
            vertices = vertices,
            normals = normals,
            uv = uv,
            triangles = source.Indices,
        };
        mesh.RecalculateBounds();
        return mesh;
    }
}