using UnityEngine;

namespace AlicizaX
{
    /// <summary>
    /// Mono 服务基类（不自动注册，适合需要手动控制注册时机的场景）。
    /// </summary>
    public abstract class MonoServiceBehaviour : MonoBehaviour, IMonoService
    {
        public ServiceContext Context { get; private set; }

        public bool IsInitialized { get; private set; }

        protected ServiceWorld World => Context.World;

        protected ServiceScope Scope => Context.Scope;

        void IService.Initialize(ServiceContext context)
        {
            if (IsInitialized)
                throw new System.InvalidOperationException($"{GetType().FullName} is already initialized.");

            Context = context;
            IsInitialized = true;
            OnServiceInitialize();
        }

        void IService.Destroy()
        {
            if (!IsInitialized) return;

            OnServiceDestroy();
            IsInitialized = false;
            Context = default;
        }

        protected virtual void OnServiceInitialize() { }

        protected virtual void OnServiceDestroy() { }
    }

    /// <summary>
    /// Mono 服务基类（自动注册到 <typeparamref name="TScope"/>）。
    /// <para>
    /// 场景服务：<c>_dontDestroyOnLoad = false</c>（默认），销毁时自动注销。<br/>
    /// 跨场景服务：<c>_dontDestroyOnLoad = true</c>，首个实例持久化并注册；
    /// 后续场景中出现的重复实例自动销毁自身。
    /// </para>
    /// <para>
    /// 子类通过 <see cref="OnAwake"/> 执行额外的 Awake 逻辑，
    /// 通过 <see cref="OnServiceInitialize"/> 执行注册后的初始化，
    /// 通过 <see cref="OnServiceDestroy"/> 执行注销前的清理。
    /// </para>
    /// </summary>
    public abstract class MonoServiceBehaviour<TScope> : MonoServiceBehaviour
        where TScope : IScope
    {
        [SerializeField] private bool _dontDestroyOnLoad = false;


        private void Awake()
        {
            OnAwake();
        }

        private void Start()
        {
            var scope = AppServices.GetOrCreateScope<TScope>();

            // 跨场景重复实例检测：契约已被占用则销毁自身
            if (scope.HasContract(GetType()))
            {
                Destroy(gameObject);
                return;
            }

            if (_dontDestroyOnLoad)
                DontDestroyOnLoad(gameObject);

            scope.Register(this);
        }

        private void OnDestroy()
        {
            if (!IsInitialized) return;
            if (!AppServices.HasWorld) return;
            if (!AppServices.TryGetScope<TScope>(out var scope)) return;

            scope.Unregister(this);
        }

        /// <summary>
        /// 在 Awake 阶段执行（早于 Start 中的自动注册）。
        /// 适合缓存组件引用等不依赖服务系统的初始化。
        /// </summary>
        protected virtual void OnAwake() { }
    }
}