using System.Collections.Generic;
using Sandbox;

public sealed partial class PerformantTerrainScatterer
{
	public enum ScattererNoiseType
	{
		None,
		Perlin,
		Simplex
	}

	public struct ScattererModelEntry
	{
		public ScattererModelEntry() { }
		[Property, Category( "Base" )] public Model Model { get; set; } = null;
		[Property, Category( "Base" ), Range( 0f, 100f )] public float Weight { get; set; } = 1f;
		[Property, Category( "Base" )] public float ZOffset { get; set; } = 0f;
		[Property, Category( "Noise Scattering" )] public ScattererNoiseType NoiseType { get; set; } = ScattererNoiseType.None;
		[Property, Category( "Noise Scattering" )] public float NoiseScale { get; set; } = 0.002f;
		[Property, Category( "Noise Scattering" ), Range( 0f, 1f )] public float NoiseThreshold { get; set; } = 0.4f;
		[Property, Category( "Performance" )] public float RenderDistance { get; set; } = 2500f;
		[Property, Category( "Terrain" )] public List<TerrainMaterial> AllowedMaterials { get; set; } = new();
		[Property, Category( "Randomization" )] public bool RandomizeScale { get; set; } = false;
		[Property, Category( "Randomization" ), ShowIf( nameof( RandomizeScale ), true )] public float MinScale { get; set; } = 0.8f;
		[Property, Category( "Randomization" ), ShowIf( nameof( RandomizeScale ), true )] public float MaxScale { get; set; } = 1.2f;
		[Property, Category( "LOD" ), Range( 0.1f, 4f )] public float LodBias { get; set; } = 1.0f;
	}

	private struct ChunkRenderData
	{
		public Vector3 Center;
		public ModelRenderBatch[] Batches;
	}

	private struct ModelRenderBatch
	{
		public Model Model;
		public Transform[] Transforms;
		public float RenderDistSq;
		public float[] LodDistancesSq;
		public int MaxLod;
	}

	private struct InstanceData
	{
		public Vector3 Position;
		public Rotation Rotation;
		public float Scale;
		public int ModelIndex;
	}

	private class ClutterChunk
	{
		public Vector3 Center;
		public readonly Dictionary<int, Transform[]> TransformsByModel = new();
	}
}