riversong-code-showcase/Source/Engine/Core/ServiceLocator.cs

using System;
using System.Collections.Generic;
using System.Reflection;
using UnityEngine;

namespace DanieleMarotta.RiversongCodeShowcase
{
    public class ServiceLocator : IServiceLocator
    {
        private Dictionary<Type, object> _services = new();

        public void RegisterService(Type serviceType, object service)
        {
            _services.Add(serviceType, service);
        }

        public object GetService(Type serviceType)
        {
            _services.TryGetValue(serviceType, out var service);
            return service;
        }

        public void Inject(object target)
        {
            var type = target.GetType();

            while (type != typeof(object))
            {
                var bindingAttr = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;
                var fields = type.GetFields(bindingAttr);

                foreach (var field in fields)
                {
                    var serviceAttribute = field.GetCustomAttribute<InjectServiceAttribute>();
                    if (serviceAttribute == null) continue;

                    var serviceType = serviceAttribute.ServiceType ?? field.FieldType;

                    var service = GetService(serviceType);
                    if (service == null)
                    {
                        Debug.LogError($"Could not resolve service of type {serviceType} when injecting {type}");
                        continue;
                    }

                    field.SetValue(target, service);
                }

                type = type.BaseType;
            }
        }
    }
}