particles/ParticleSimulation/Simulation/ParticleType.cs

using System.Collections.Generic;
using Godot;

namespace Particles.ParticleSimulation
{
    public struct ParticleRelationshipProps
    {
        public ParticleRelationshipProps(float minRadius, float maxRadius, float force)
        {
            MinRadius = minRadius;
            MaxRadius = maxRadius;
            Force = force;
        }

        public float MinRadius { get; }
        public float MaxRadius { get; }
        public float Force { get; }
    }

    public class ParticleType
    {
        private readonly Dictionary<ParticleType, ParticleRelationshipProps> _particleRelationships =
            new Dictionary<ParticleType, ParticleRelationshipProps>();

        private float _hue;

        public float Hue
        {
            get => _hue;
            set => _hue = Mathf.Clamp(value, 0, 1);
        }

        public void AddRelationship(ParticleType type, ParticleRelationshipProps props)
        {
            if (_particleRelationships.ContainsKey(type))
                return;
            _particleRelationships[type] = props;
        }

        public void RemoveRelationship(ParticleType type)
        {
            if (_particleRelationships.ContainsKey(type))
                _particleRelationships.Remove(type);
        }

        public ParticleRelationshipProps GetRelationship(ParticleType type)
        {
            return _particleRelationships[type];
        }
    }
}