using System.Collections.Generic;
using System.Linq;
using UnityEngine;

namespace AibisDream.SaveSystem
{
    /// <summary>
    /// 快照 section 的稳定字符串 id。
    /// 用于 JSON key、Provider 注册与反序列化，避免使用 AssemblyQualifiedName。
    /// </summary>
    public static class SnapshotProviderIds
    {
        public const string Environment = "env";
        public const string Actor = "actor";
        public const string Audio = "audio";
        public const string Timeline = "timeline";
        public const string Screen = "screen";
        public const string PlayTool = "playTool";
        public const string Showcase = "showcase";
        public const string Subway = "subway";
        public const string PunchTape = "punchTape";
        public const string Fix = "fix";
        public const string FixPanel = "fixPanel";
        public const string BodyModule = "bodyModule";
        public const string Eye = "eye";

        /// <summary>
        /// P1 应参与 Capture 的 provider 清单。
        /// <see cref="SnapshotRegistry.ValidateRequiredProviders"/> 据此告警缺失项；不含深度维修。
        /// scene 与 macro 已提升到 <see cref="SaveSnapshot"/> 根对象，由框架直管。
        /// </summary>
        public static readonly string[] RequiredForCapture =
        {
            Environment, Actor, Audio, Timeline, Subway, Fix, Showcase, PlayTool, Screen
        };
    }

    /// <summary>
    /// 运行时登记全部 <see cref="ISnapshotProvider"/>。
    /// Capture/Restore 时按 <see cref="ISnapshotProvider.RestoreOrder"/> 迭代；
    /// 不使用「谁注册了谁才存」的隐式行为，RequiredForCapture 用于显式校验。
    /// </summary>
    public static class SnapshotRegistry
    {
        private static readonly Dictionary<string, ISnapshotProvider> Providers = new();
        private static bool _initialized;

        /// <summary>幂等初始化：注册 P1 所需的全部 Provider。</summary>
        public static void EnsureInitialized()
        {
            if (_initialized) return;
            _initialized = true;

            Register(new EnvironmentSnapshotProvider());
            Register(new ActorSnapshotProvider());
            Register(new AudioSnapshotProvider());
            Register(new TimelineSnapshotProvider());
            Register(new SubwaySnapshotProvider());
            Register(new PunchTapeSnapshotProvider());
            Register(new FixSnapshotProvider());
            Register(new FixPanelSnapshotProvider());
            Register(new BodyModuleSnapshotProvider());
            Register(new EyeSnapshotProvider());
            Register(new ShowcaseSnapshotProvider());
            Register(new PlayToolSnapshotProvider());
            Register(new ScreenSnapshotProvider());
        }

        /// <summary>注册 provider；同 SaveId 后者覆盖前者。</summary>
        public static void Register(ISnapshotProvider provider)
        {
            if (provider == null) return;
            Providers[provider.SaveId] = provider;
        }

        public static void Unregister(string saveId)
        {
            Providers.Remove(saveId);
        }

        public static bool TryGet(string saveId, out ISnapshotProvider provider)
        {
            return Providers.TryGetValue(saveId, out provider);
        }

        /// <summary>按 RestoreOrder 升序返回，供还原流水线使用。</summary>
        public static IReadOnlyList<ISnapshotProvider> GetOrderedProviders()
        {
            return Providers.Values.OrderBy(p => p.RestoreOrder).ToList();
        }

        /// <summary>
        /// 校验 <see cref="SnapshotProviderIds.RequiredForCapture"/>；
        /// 缺失时 <c>LogWarning</c> 但不阻断 Capture。
        /// </summary>
        public static void ValidateRequiredProviders()
        {
            foreach (var saveId in SnapshotProviderIds.RequiredForCapture)
            {
                if (!Providers.ContainsKey(saveId))
                {
                    Debug.LogWarning($"[SnapshotRegistry] 缺少快照 provider: {saveId}");
                }
            }
        }
    }
}