zeling_v2/Assets/Scripts/Localization/LocalizationManager.cs

// Assets/Scripts/Localization/LocalizationManager.cs
// 本地化管理器（运行时 JSON 文件驱动）。
//
// 数据格式（放在 Resources/Localization/{Language}/{TableName}.json）：
// {
//   "entries": [
//     { "key": "ui_start",    "value": "开始游戏" },
//     { "key": "ui_settings", "value": "设置" }
//   ]
// }
//
// 推荐用法（通过 ServiceLocator 获取 ILocalizationService 实例）：
//   ServiceLocator.GetOrDefault<ILocalizationService>()?.Get("ui_start")
//   ServiceLocator.GetOrDefault<ILocalizationService>()?.SetLanguage(Language.English)
//
// 便捷静态方法（内部仍走 ServiceLocator，推荐在热路径之外使用）：
//   LocalizationManager.Get("ui_start")
//   LocalizationManager.Get("dlg_hero", "Dialogue")

using System;
using System.Collections.Generic;
using UnityEngine;
using BaseGames.Core;
using BaseGames.Core.Save;

namespace BaseGames.Localization
{
    /// <summary>
    /// 本地化管理器（MonoBehaviour，挂在 Persistent 场景）。
    /// 实现 ILocalizationService + ISaveable，通过 ServiceLocator 注册。
    /// 语言偏好持久化到 SaveData.Settings.Language，不使用 PlayerPrefs。
    /// </summary>
    public class LocalizationManager : MonoBehaviour, ILocalizationService, ISaveable
    {
        // 默认语言：回退链：当前语言 → 英语 → 直接返回 key
        private Language _currentLanguage = Language.ChineseSimplified;
        private readonly Language _fallbackLanguage = Language.English;

        // 双层缓存：languageKey("ChineseSimplified/UI") → (key → value)
        private readonly Dictionary<string, Dictionary<string, string>> _cache = new();

        // ILocalizationService 实例事件
        private event Action<Language> _onLanguageChanged;
        event Action<Language> ILocalizationService.OnLanguageChanged
        {
            add    => _onLanguageChanged += value;
            remove => _onLanguageChanged -= value;
        }

        // ── 生命周期 ──────────────────────────────────────────────────────────
        private void Awake()
        {
            if (ServiceLocator.GetOrDefault<ILocalizationService>() != null) { Destroy(gameObject); return; }
            ServiceLocator.Register<ILocalizationService>(this);
        }

        private void OnEnable()
        {
            ServiceLocator.GetOrDefault<ISaveableRegistry>()?.Register(this);
        }

        private void OnDisable()
        {
            ServiceLocator.GetOrDefault<ISaveableRegistry>()?.Unregister(this);
        }

        private void OnDestroy()
        {
            ServiceLocator.Unregister<ILocalizationService>(this);
        }

        // ── ILocalizationService ──────────────────────────────────────────────
        public Language CurrentLanguage => _currentLanguage;

        /// <summary>切换游戏语言并通知所有订阅者刷新文本。</summary>
        public void SetLanguage(Language language)
        {
            if (_currentLanguage == language) return;
            _currentLanguage = language;
            _onLanguageChanged?.Invoke(language);
        }

        /// <summary>
        /// 获取本地化字符串（显式接口实现）。
        /// 查找顺序：当前语言 → 回退语言（English）→ 直接返回 key。
        /// </summary>
        string ILocalizationService.Get(string key, string table)
        {
            if (string.IsNullOrEmpty(key)) return string.Empty;

            // 1. 尝试当前语言
            if (TryGetFromTable(_currentLanguage, table, key, out string text))
                return text;

            // 2. 回退到 English
            if (_currentLanguage != _fallbackLanguage &&
                TryGetFromTable(_fallbackLanguage, table, key, out text))
                return text;

            // 3. 最终回退：原始 key
            return key;
        }

        // ── ISaveable ─────────────────────────────────────────────────────────
        public void OnSave(SaveData data)
        {
            if (data?.Settings == null) return;
            data.Settings.Language = _currentLanguage.ToString();
        }

        public void OnLoad(SaveData data)
        {
            if (data?.Settings == null || string.IsNullOrEmpty(data.Settings.Language)) return;
            if (Enum.TryParse<Language>(data.Settings.Language, out var lang))
                SetLanguage(lang);
        }

        // ── 静态便捷方法 ─────────────────────────────────────────────────────────
        /// <summary>
        /// 静态快捷获取本地化字符串。委托给 ILocalizationService 实例；服务未注册时直接返回 key。
        /// </summary>
        public static string Get(string key, string table = "UI")
            => ServiceLocator.GetOrDefault<ILocalizationService>()?.Get(key, table) ?? key;

        // ── 内部 ─────────────────────────────────────────────────────────────
        private bool TryGetFromTable(Language language, string table, string key, out string value)
        {
            var cacheKey = $"{language}/{table}";
            if (!_cache.TryGetValue(cacheKey, out var dict))
            {
                dict = LoadTable(language, table);
                _cache[cacheKey] = dict;   // 即使加载失败也存入空字典，避免每帧重试
            }
            if (dict != null && dict.TryGetValue(key, out value)) return true;
            value = null;
            return false;
        }

        /// <summary>
        /// 从 Resources/Localization/{language}/{table}.json 加载字符串表。
        /// 返回 null 表示文件不存在。
        /// </summary>
        private static Dictionary<string, string> LoadTable(Language language, string table)
        {
            string path = $"Localization/{language}/{table}";
            var asset = Resources.Load<TextAsset>(path);
            if (asset == null) return null;

            var parsed = JsonUtility.FromJson<StringTableJson>(asset.text);
            if (parsed?.entries == null) return null;

            var dict = new Dictionary<string, string>(parsed.entries.Count, StringComparer.Ordinal);
            foreach (var entry in parsed.entries)
                if (!string.IsNullOrEmpty(entry.key))
                    dict[entry.key] = entry.value ?? string.Empty;

            return dict;
        }

        // ── 序列化辅助类型 ────────────────────────────────────────────────────

        [Serializable]
        private class StringTableJson
        {
            public List<StringEntry> entries;
        }

        [Serializable]
        private class StringEntry
        {
            public string key;
            public string value;
        }
    }
}