trail-into-darkness/Assets/Code/GameState/Entities/ModifiersFactory.cs

using Jovian.Logger;
using System;
using System.Collections.Generic;
using ZLinq;
using UnityEngine;

namespace Nox.Game {
    public interface IModifier {
        string Name { get; }
        Guid Id { get; }
        StatType StatType { get; }
        AttributeType AttributeType { get; }
        ModifierOperation Operation { get; }
        float Value { get; }
    }

    public interface IModifiersFactory {
        IReadOnlyCollection<IModifier> GetAll();
        IModifier GetById(Guid modifierId);
        IReadOnlyCollection<IModifier> GetModifiersFor(IEntityDefinition character);
        bool TryAddModifier(IEntityDefinition character, Guid modiferId);
    }

    public enum ModifierOperation {
        None,
        Flat,
        Addition,
        Multiplication,
        Percentage
    }

    [Serializable]
    public sealed class ModifierDefinition : IModifier {
        [field: SerializeField] public string Name { get; set; }
        public Guid Id { get; set; }
        [field: SerializeField] public StatType StatType { get; set; }
        [field: SerializeField] public AttributeType AttributeType { get; set; }
        [field: SerializeField] public ModifierOperation Operation { get; set; }
        [field: SerializeField] public float Value { get; set; }
    }

    [Serializable]
    public sealed class ModifiersData {
        public List<ModifierDefinition> modifiers = new ();
    }

    public class ModifiersFactory : IModifiersFactory {
        private readonly ModifiersRegistry modifiersRegistry;
        private readonly Dictionary<Guid, IModifier> modifierPool = new ();

        public ModifiersFactory(ModifiersRegistry modifiersRegistry) {
            this.modifiersRegistry = modifiersRegistry;
            var allAvailableModifiers = modifiersRegistry.modifiersData;
            foreach(var modifier in allAvailableModifiers.modifiers) {
                modifierPool.Add(modifier.Id, modifier);
            }
        }

        public IReadOnlyCollection<IModifier> GetAll() {
            return modifiersRegistry.modifiersData.modifiers;
        }
        public IModifier GetById(Guid modifierId) {
            return modifiersRegistry.modifiersData.modifiers.AsValueEnumerable().FirstOrDefault(m => m.Id == modifierId);
        }
        public IReadOnlyCollection<IModifier> GetModifiersFor(IEntityDefinition character) {
            return character.Modifiers.modifiers;
        }
        public bool TryAddModifier(IEntityDefinition character, Guid modifierId) {
            if(character == null) {
                return false;
            }

            if(modifierId == Guid.Empty) {
                GlobalLogger.LogException("Cannot add a modifier with an empty ID!", LogCategory.GameLogic);
                return false;
            }

            if(character.Modifiers.modifiers.AsValueEnumerable().Any(p => p != null && p.Id == modifierId)) {
                return false;
            }

            if(!modifierPool.TryGetValue(modifierId, out var modifier)) {
                return false;
            }

            character.Modifiers.modifiers.Add(new ModifierDefinition {
                Id = modifier.Id,
                Name = modifier.Name,
                StatType = modifier.StatType,
                AttributeType = modifier.AttributeType,
                Operation = modifier.Operation,
                Value = modifier.Value
            });

            return true;
        }
    }
}