namespace AibisDream.SaveSystem
{
    /// <summary>
    /// 从 <see cref="SaveSnapshot"/> 根对象直接读取的宏观摘要（场景 / 章节 SO / YarnProject）。
    /// <para>
    /// scene 与 anchor 已提升到根对象，无需再从 sections 字典派生。
    /// 槽位 / 「继续游戏」等 UI 在需要展示时调用 <see cref="From"/> 即可。
    /// </para>
    /// </summary>
    public readonly struct SaveSnapshotSummary
    {
        /// <summary>Addressable 场景 key（来自 <see cref="SaveSnapshot.scene"/>）。</summary>
        public readonly string SceneName;

        /// <summary>当前 <c>TalkSceneSO</c> 的 asset 名称（来自 <see cref="AnchorSnapshot.sceneSoName"/>）。</summary>
        public readonly string SceneSoName;

        /// <summary>当前 <c>YarnProject</c> 的 name（来自 <see cref="AnchorSnapshot.yarnProjectId"/>）。</summary>
        public readonly string YarnProjectId;

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

        /// <summary>从快照根对象直接读取宏观摘要。</summary>
        public static SaveSnapshotSummary From(SaveSnapshot snapshot)
        {
            if (snapshot == null)
            {
                return new SaveSnapshotSummary(null, null, null);
            }

            var sceneName = snapshot.scene?.sceneName;
            var sceneSoName = snapshot.anchor?.sceneSoName;
            var yarnProjectId = snapshot.anchor?.yarnProjectId;

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