using Ichni.Menu;
using Ichni.Menu.UI;
using System.Collections.Generic;
using UnityEngine;

namespace Ichni.Story
{
    /// <summary>
    /// TutorialBlock 的菜单层流程协调器。
    /// 负责验证配置、生成通用 SelectionBox 选项、写入剧情进度，并在“游玩”时发起 GameScene 运行。
    /// 不保存“教程成绩”或“教程是否通关”；本阶段规则是玩家确认游玩或跳过即视为已处理。
    /// </summary>
    public static class TutorialFlowController
    {
        /// <summary>
        /// 由 <see cref="UI.TutorialBlockView"/> 点击时调用。配置无效或 SelectionBox 页面未配置时只报错，不修改剧情进度。
        /// </summary>
        public static void RequestTutorial(StoryBlockDefinition tutorialBlock)
        {
            if (!TryResolveTutorialRunData(tutorialBlock, out ChapterSelectionUnit chapter,
                    out SongItemData song, out DifficultyData difficulty))
            {
                return;
            }

            MenuManager menuManager = MenuManager.instance;
            SelectionBoxUIPage selectionBoxPage = menuManager?.selectionBoxUIPage;
            if (selectionBoxPage == null)
            {
                Debug.LogWarning("[TutorialFlowController] MenuManager 未配置 SelectionBoxUIPage，教程不会被解锁。");
                return;
            }

            // TutorialFlowController 只描述“有哪些选择、各自触发什么效果”；
            // 具体按钮由通用 SelectionBox 在运行时生成，后续其它系统可复用同一 UI。
            selectionBoxPage.Show(
                tutorialBlock.tutorialName,
                string.Empty,
                new List<SelectionBoxOption>
                {
                    new("游玩教程", () => PlayTutorial(tutorialBlock, chapter, song, difficulty)),
                    new("跳过教程", () => SkipTutorial(tutorialBlock))
                });
        }

        private static void PlayTutorial(StoryBlockDefinition tutorialBlock, ChapterSelectionUnit chapter,
            SongItemData song, DifficultyData difficulty)
        {
            MenuManager menuManager = MenuManager.instance;
            if (menuManager == null || menuManager.isEnteringGame)
            {
                Debug.LogWarning("[TutorialFlowController] 菜单正在切换，忽略教程游玩请求。");
                return;
            }

            // 先验证能否启动 GameScene，再写入“已处理”进度；避免无效配置导致错误解锁。
            if (!CanBeginTutorialGame(chapter, song, difficulty))
                return;

            if (!StoryProgress.ResolveTutorial(tutorialBlock))
                return;

            // 规则：玩家确认“游玩教程”的瞬间即解锁后续剧情，不等待教程结算。
            menuManager.TryBeginGame(chapter, song, difficulty, MenuReturnDestination.Story,
                menuManager.storyUIPage);
        }

        private static void SkipTutorial(StoryBlockDefinition tutorialBlock)
        {
            // 规则：玩家确认“跳过教程”的瞬间即解锁后续剧情，并保留在故事树。
            StoryProgress.ResolveTutorial(tutorialBlock);
        }

        private static bool CanBeginTutorialGame(ChapterSelectionUnit chapter, SongItemData song, DifficultyData difficulty)
        {
            if (MenuManager.instance == null || InformationTransistor.instance == null ||
                !MenuManager.instance.CanBeginGame)
            {
                Debug.LogWarning("[TutorialFlowController] MenuManager、InformationTransistor 或 GameScene 预加载未就绪，无法进入教程。");
                return false;
            }

            if (chapter == null || song == null || difficulty == null)
            {
                Debug.LogWarning("[TutorialFlowController] 教程缺少章节、歌曲或难度配置，无法进入教程。");
                return false;
            }

            return true;
        }

        /// <summary>
        /// 解析 TutorialBlock 的 Key、教程曲目与稳定难度 ID。
        /// 任何一项缺失都会失败且不写入剧情变量，防止错误配置意外解锁后续内容。
        /// </summary>
        private static bool TryResolveTutorialRunData(StoryBlockDefinition tutorialBlock,
            out ChapterSelectionUnit chapter, out SongItemData song, out DifficultyData difficulty)
        {
            chapter = ChapterSelectionManager.instance?.currentChapter;
            song = null;
            difficulty = null;

            if (tutorialBlock == null || tutorialBlock.blockType != StoryBlockType.Tutorial ||
                string.IsNullOrWhiteSpace(tutorialBlock.tutorialKey) ||
                string.IsNullOrWhiteSpace(tutorialBlock.tutorialProgressVariable) ||
                tutorialBlock.tutorialDifficultySaveId < 0)
            {
                Debug.LogWarning($"[TutorialFlowController] TutorialBlock '{tutorialBlock?.blockId}' 的 Tutorial Key、Progress Variable 或 Difficulty Save ID 未配置完整。");
                return false;
            }

            TutorialCollection collection = ChapterSelectionManager.instance?.tutorialCollection;
            if (chapter == null || collection == null || !collection.TryGetTutorialSong(tutorialBlock.tutorialKey, out song))
            {
                Debug.LogWarning($"[TutorialFlowController] TutorialBlock '{tutorialBlock.blockId}' 无法解析章节或教程曲目。");
                return false;
            }

            if (song.difficultyDataList == null)
            {
                Debug.LogWarning($"[TutorialFlowController] 教程 '{tutorialBlock.tutorialKey}' 没有难度列表。");
                return false;
            }

            foreach (DifficultyData candidate in song.difficultyDataList)
            {
                if (candidate != null && candidate.isAvailable &&
                    candidate.saveDifficultyId == tutorialBlock.tutorialDifficultySaveId)
                {
                    difficulty = candidate;
                    return true;
                }
            }

            Debug.LogWarning($"[TutorialFlowController] 教程 '{tutorialBlock.tutorialKey}' 中不存在可用的 Difficulty Save ID '{tutorialBlock.tutorialDifficultySaveId}'。");
            return false;
        }
    }
}