using System.Collections.Generic;
using System.Reflection;
using Ichni.Story.UI;
using UnityEngine;
using UnityEngine.Events;
using Yarn.Unity;
using Yarn.Unity.UnityLocalization;

namespace Ichni.Story.Dialogue
{
    /// <summary>
    /// 故事树 block 与 Yarn <see cref="DialogueRunner"/> 之间的桥接控制器。
    /// <para>点击文本块 → 启动对应 Yarn 节点；对话结束 → 持久化剧情变量、标记 block 完成、
    /// 重算解锁并存档、依次执行结束回调（如歌曲解锁提示，阶段 4 使用）。</para>
    /// </summary>
    public class StoryDialogueController : MonoBehaviour
    {
        public static StoryDialogueController instance;

        [Header("References")]
        [Tooltip("驱动 Yarn 对话的 DialogueRunner。")]
        public DialogueRunner dialogueRunner;

        [Tooltip("故事树页面：对话进行时淡出、结束后淡入（可选）。")]
        public StoryUIPage storyUIPage;

        /// <summary>
        /// 对话结束后依次执行并清空的回调队列。供 <c>unlock_song</c> 等 Yarn 命令（阶段 4）
        /// 把"解锁提示"排队到对话结束后弹出。
        /// </summary>
        [System.NonSerialized] public List<UnityAction> dialogueEndActions = new List<UnityAction>();

        // 当前正在播放对话的 block id；对话结束时据此标记完成
        private string _activeBlockId;

        private void Awake()
        {
            instance = this;
            EnsureUnityLocalisedLineProvider();
        }

        private void OnEnable()
        {
            if (dialogueRunner != null && dialogueRunner.onDialogueComplete != null)
                dialogueRunner.onDialogueComplete.AddListener(HandleDialogueComplete);
        }

        private void OnDisable()
        {
            if (dialogueRunner != null && dialogueRunner.onDialogueComplete != null)
                dialogueRunner.onDialogueComplete.RemoveListener(HandleDialogueComplete);
        }

        /// <summary>
        /// 播放某文本块对应的 Yarn 节点。若对话已在进行、引用缺失或节点名为空则忽略。
        /// </summary>
        public void PlayBlock(TextBlockView block)
        {
            if (block == null) return;

            if (dialogueRunner == null)
            {
                Debug.LogError("[StoryDialogueController] 未配置 DialogueRunner，无法开始对话。");
                return;
            }

            if (dialogueRunner.IsDialogueRunning)
            {
                Debug.LogWarning("[StoryDialogueController] 已有对话在进行中，忽略本次点击。");
                return;
            }

            if (string.IsNullOrEmpty(block.YarnNodeName))
            {
                Debug.LogWarning($"[StoryDialogueController] block '{block.blockId}' 未配置 yarnNodeName，无法开始对话。");
                return;
            }

            // 将 DialogueRunner 的 YarnProject 对齐到当前章节（支持多章节共用一个 Runner）
            EnsureProjectForCurrentChapter();

            _activeBlockId = block.blockId;

            if (storyUIPage != null)
                storyUIPage.FadeOut();

            // StartDialogue 返回 YarnTask；此处即发即忘，完成由 onDialogueComplete 处理
            dialogueRunner.StartDialogue(block.YarnNodeName).Forget();
        }

        // 将 DialogueRunner 的 YarnProject 切换为当前已构建章节的 StoryData.yarnProject（若不同且未在运行）
        private void EnsureProjectForCurrentChapter()
        {
            StoryTreeController tree = StoryManager.instance != null ? StoryManager.instance.treeController : null;
            StoryData data = tree != null ? tree.ActiveStoryData : null;

            if (data == null || data.yarnProject == null) return;

            if (dialogueRunner.YarnProject != data.yarnProject && !dialogueRunner.IsDialogueRunning)
                dialogueRunner.SetProject(data.yarnProject);
        }

        /// <summary>
        /// DialogueRunner.lineProvider 为 [SerializeReference] internal 字段。
        /// Inspector 的 "Use Unity Localised Line Provider" 按钮有时无法将 MonoBehaviour
        /// 引用正确持久化到该字段；此方法在运行时用反射补救，确保使用正确的 Provider。
        /// </summary>
        private void EnsureUnityLocalisedLineProvider()
        {
            if (dialogueRunner == null) return;

            FieldInfo field = typeof(DialogueRunner).GetField(
                "lineProvider",
                BindingFlags.NonPublic | BindingFlags.Instance);

            if (field == null) return;

            // 已经是 UnityLocalisedLineProvider 则无需处理
            if (field.GetValue(dialogueRunner) is UnityLocalisedLineProvider) return;

            UnityLocalisedLineProvider provider =
                dialogueRunner.GetComponent<UnityLocalisedLineProvider>();

            if (provider != null)
            {
                field.SetValue(dialogueRunner, provider);
                Debug.Log("[StoryDialogueController] Assigned UnityLocalisedLineProvider to DialogueRunner.lineProvider.");
            }
            else
            {
                Debug.LogWarning("[StoryDialogueController] UnityLocalisedLineProvider not found on DialogueRunner's GameObject. Localized line text will be unavailable.");
            }
        }

        private void HandleDialogueComplete()
        {
            // 持久化对话过程中写入的全局剧情变量
            if (GameSaveManager.instance != null && GameSaveManager.instance.StorySaveModule != null)
                GameSaveManager.instance.StorySaveModule.SaveVariables();

            // 标记 block 完成 → 重算解锁 → 存档（OnBlockCompleted 内部已去重并保存章节进度）
            if (!string.IsNullOrEmpty(_activeBlockId) &&
                StoryManager.instance != null && StoryManager.instance.treeController != null)
            {
                StoryManager.instance.treeController.OnBlockCompleted(_activeBlockId);
            }

            _activeBlockId = null;

            // 依次执行并清空结束回调（如歌曲解锁提示）
            if (dialogueEndActions.Count > 0)
            {
                List<UnityAction> pending = new List<UnityAction>(dialogueEndActions);
                dialogueEndActions.Clear();
                foreach (UnityAction action in pending)
                    action?.Invoke();
            }

            if (storyUIPage != null)
                storyUIPage.FadeIn();
        }
    }
}