namespace AibisDream.SaveSystem
{
    /// <summary>
    /// 从 <see cref="SaveSnapshot.sections"/> 现算的宏观摘要（场景 / 章节 SO / YarnProject）。
    /// <para>
    /// 替代已移除的顶层 <c>macroStage</c> 冗余字段：sections["scene"] / sections["macro"] 为唯一来源，
    /// 槽位 / 「继续游戏」等 UI 在需要展示时调用 <see cref="From"/> 派生，避免重复字段与读写漂移。
    /// </para>
    /// </summary>
    public readonly struct SaveSnapshotSummary
    {
        /// <summary>Addressable 场景 key，如 <c>Scene/ClinicOut</c>（来自 sections["scene"]）。</summary>
        public readonly string SceneName;

        /// <summary>当前 <c>TalkSceneSO</c> 的 asset 名称（来自 sections["macro"]）。</summary>
        public readonly string SceneSoName;

        /// <summary>当前 <c>YarnProject</c> 的 name（来自 sections["macro"]，缺省回退到 anchor）。</summary>
        public readonly string YarnProjectId;

        public SaveSnapshotSummary(string sceneName, string sceneSoName, string yarnProjectId)
        {
            SceneName = sceneName;
            SceneSoName = sceneSoName;
            YarnProjectId = yarnProjectId;
        }

        /// <summary>从快照派生宏观摘要；兼容 sections 为强类型 DTO 或读盘后的 JObject。</summary>
        public static SaveSnapshotSummary From(SaveSnapshot snapshot)
        {
            if (snapshot?.sections == null)
            {
                return new SaveSnapshotSummary(null, null, snapshot?.anchor?.yarnProjectId);
            }

            string sceneName = null;
            if (snapshot.sections.TryGetValue(SnapshotProviderIds.Scene, out var sceneRaw)
                && SnapshotSectionDeserializer.Coerce(SnapshotProviderIds.Scene, sceneRaw) is SceneSnapshotDto scene)
            {
                sceneName = scene.sceneName;
            }

            string sceneSoName = null;
            string yarnProjectId = null;
            if (snapshot.sections.TryGetValue(SnapshotProviderIds.Macro, out var macroRaw)
                && SnapshotSectionDeserializer.Coerce(SnapshotProviderIds.Macro, macroRaw) is MacroSnapshotDto macro)
            {
                sceneSoName = macro.sceneSoName;
                yarnProjectId = macro.yarnProjectId;
            }

            if (string.IsNullOrEmpty(yarnProjectId))
            {
                yarnProjectId = snapshot.anchor?.yarnProjectId;
            }

            return new SaveSnapshotSummary(sceneName, sceneSoName, yarnProjectId);
        }
    }
}