using UnityEngine;

namespace Ichni.Story
{
    /// <summary>
    /// 修改章节剧情进度的唯一业务入口。
    /// <para>StoryVariables 只管理内存字典；本类负责在写入前创建 Timeline 回滚快照、保存当前章节、
    /// 并刷新剧情树状态。Yarn 指令、TutorialBlock 与未来小游戏都应通过这里写入。</para>
    /// </summary>
    public static class StoryProgress
    {
        // 对话开始时由 StoryDialogueController 设定。它用于判断本次变量/选项写入属于哪个 Block，
        // 从而在 Marker 所在列首次被执行前截取正确快照。
        private static string _activeMutationBlockId;

        /// <summary>
        /// 声明接下来的剧情变量或选项写入属于指定 Block。仅在对话运行期间有效。
        /// </summary>
        public static void BeginBlockMutation(string blockId)
        {
            _activeMutationBlockId = blockId;
            TryCaptureActiveBlockSnapshot();
        }

        /// <summary>
        /// 结束指定 Block 的写入上下文，避免后续非剧情系统错误沿用旧的来源 Block。
        /// </summary>
        public static void EndBlockMutation(string blockId)
        {
            if (_activeMutationBlockId == blockId)
                _activeMutationBlockId = null;
        }

        /// <summary>
        /// 为当前写入来源捕获 Marker 快照。无章节、无来源 Block 或无对应 Marker 时安全返回 false。
        /// </summary>
        public static bool TryCaptureActiveBlockSnapshot()
        {
            StoryTreeController treeController = StoryManager.instance?.treeController;
            string blockId = !string.IsNullOrEmpty(_activeMutationBlockId)
                ? _activeMutationBlockId
                : treeController?.currentBlock?.blockId;

            return treeController != null && !string.IsNullOrEmpty(blockId) &&
                   treeController.EnsureRollbackSnapshotsForBlock(blockId);
        }

        public static bool SetBoolAndRefresh(string variableName, bool value) =>
            TryWrite(variableName, () => StoryVariables.SetBool(variableName, value));

        public static bool SetIntAndRefresh(string variableName, int value) =>
            TryWrite(variableName, () => StoryVariables.SetInt(variableName, value));

        public static bool AddIntAndRefresh(string variableName, int delta) =>
            SetIntAndRefresh(variableName, StoryVariables.GetInt(variableName) + delta);

        public static bool SetFloatAndRefresh(string variableName, float value) =>
            TryWrite(variableName, () => StoryVariables.SetFloat(variableName, value));

        public static bool AddFloatAndRefresh(string variableName, float delta) =>
            SetFloatAndRefresh(variableName, StoryVariables.GetFloat(variableName) + delta);

        public static bool SetStringAndRefresh(string variableName, string value) =>
            TryWrite(variableName, () => StoryVariables.SetString(variableName, value));

        public static bool RemoveVariableAndRefresh(string variableName) =>
            TryWrite(variableName, () => StoryVariables.Remove(variableName));

        /// <summary>
        /// 处理 TutorialBlock 的“游玩”或“跳过”确认。两种选择都会立即写入进度变量并完成 Block；
        /// 完成后的 TutorialBlock 仍可点击，是因为其 View 自身允许 Completed 状态交互。
        /// </summary>
        public static bool ResolveTutorial(StoryBlockDefinition tutorialBlock)
        {
            if (tutorialBlock == null || tutorialBlock.blockType != StoryBlockType.Tutorial ||
                string.IsNullOrWhiteSpace(tutorialBlock.blockId) ||
                string.IsNullOrWhiteSpace(tutorialBlock.tutorialProgressVariable))
            {
                Debug.LogWarning("[StoryProgress] TutorialBlock 缺少必要的 Block ID 或 Progress Variable。");
                return false;
            }

            StoryTreeController treeController = StoryManager.instance?.treeController;
            if (treeController == null)
            {
                Debug.LogWarning("[StoryProgress] StoryTreeController 未就绪，拒绝写入教程进度。");
                return false;
            }

            // Tutorial 不经过 Yarn 对话上下文，显式由自己的 Block ID 触发同一套快照逻辑。
            treeController.EnsureRollbackSnapshotsForBlock(tutorialBlock.blockId);
            if (!SetBoolAndRefresh(tutorialBlock.tutorialProgressVariable, true))
                return false;

            treeController.OnBlockCompleted(tutorialBlock.blockId);
            return true;
        }

        /// <summary>
        /// 统一完成“检查上下文 → 捕获回滚点 → 写变量 → 保存章节 → 刷新树”的事务性流程。
        /// </summary>
        private static bool TryWrite(string variableName, System.Action write)
        {
            if (string.IsNullOrWhiteSpace(variableName))
            {
                Debug.LogWarning("[StoryProgress] 剧情变量名为空，拒绝写入。");
                return false;
            }

            if (GameSaveManager.instance?.StorySaveModule == null || StoryManager.instance?.treeController == null)
            {
                Debug.LogWarning("[StoryProgress] 剧情章节或 StorySaveModule 未就绪，拒绝写入变量。");
                return false;
            }

            // 快照必须在写入前完成，才能保证 Marker 回滚真正恢复到该列之前。
            TryCaptureActiveBlockSnapshot();
            write();
            GameSaveManager.instance.StorySaveModule.SaveActiveChapter();
            StoryManager.instance.treeController.RefreshAllStates();
            return true;
        }
    }
}