using System;
using System.Collections.Generic;
using DG.Tweening;
using UnityEngine;
using UnityEngine.Localization.Settings;
using UnityEngine.UI;

namespace Ichni.Story
{
    /// <summary>
    /// 场景中常驻 Helper 的交互控制器。
    /// <para>点击后会按剧情条件筛选并加权随机抽取一条台词，实例化 HelperTalk Prefab 显示；
    /// 此过程不修改剧情变量、Block 完成状态或存档。</para>
    /// </summary>
    [RequireComponent(typeof(Button))]
    public class StoryHelperController : MonoBehaviour
    {
        [Header("References")]
        [SerializeField, Tooltip("承接 Helper 点击的 Button。建议挂在固定根节点，而非会移动的视觉节点上。")]
        private Button helperButton;

        [SerializeField, Tooltip("当前 Helper 的视觉 Presenter。未来可替换为 Spine 或 Live2D 对应实现。")]
        private StoryHelperVisualPresenter visualPresenter;

        [SerializeField, Tooltip("点击后实例化的 HelperTalk Prefab。它独立于 MessageBox。")]
        private StoryHelperTalk helperTalkPrefab;

        [SerializeField, Tooltip("运行时 HelperTalk 的父节点。留空时使用当前 Helper 根节点。")]
        private Transform helperTalkContainer;

        [Header("Motion Roots")]
        [SerializeField, Tooltip("只承担循环漂浮动画的节点。")]
        private RectTransform idleRoot;

        [SerializeField, Tooltip("只承担点击反馈的节点。它应位于 Idle Root 内部，避免与循环漂浮争夺同一属性。")]
        private RectTransform clickRoot;

        [Header("Idle Animation")]
        [SerializeField, Min(0f), Tooltip("循环漂浮的最大纵向偏移（Canvas 单位）。")]
        private float idleFloatDistance = 8f;

        [SerializeField, Min(0.05f), Tooltip("从基准位置移动到最高点或最低点的单程时间。")]
        private float idleHalfDuration = 1.35f;

        [Header("Click Animation")]
        [SerializeField, Min(0.01f), Tooltip("点击缩放与位移反馈持续时间。")]
        private float clickPunchDuration = 0.2f;

        [SerializeField, Min(0f), Tooltip("点击时的缩放强度；0.035 表示约 3.5% 的轻微放大。")]
        private float clickPunchScale = 0.035f;

        [SerializeField, Min(0f), Tooltip("点击时的纵向位移反馈（Canvas 单位）。")]
        private float clickPunchOffset = 5f;

        [SerializeField, Min(0f), Tooltip("连续点击的最小间隔，防止重复实例化大量气泡。")]
        private float clickCooldown = 0.3f;

        private readonly List<StoryHelperDialogueDefinition> _eligibleDialogues = new();

        private Sequence _idleSequence;
        private Sequence _clickSequence;
        private StoryHelperTalk _activeTalk;
        private Vector2 _idleBasePosition;
        private Vector2 _clickBasePosition;
        private Vector3 _clickBaseScale;
        private string _lastDialogueId;
        private StoryHelperData _appliedHelperData;
        private StoryManager _subscribedStoryManager;
        private float _nextClickTime;

        private void Awake()
        {
            if (helperButton == null)
                helperButton = GetComponent<Button>();
            if (idleRoot == null)
                idleRoot = transform as RectTransform;
            if (clickRoot == null && visualPresenter != null)
                clickRoot = visualPresenter.transform as RectTransform;
            if (helperTalkContainer == null)
                helperTalkContainer = transform;

            CacheBaseTransforms();
        }

        private void OnEnable()
        {
            if (helperButton != null)
                helperButton.onClick.AddListener(HandleHelperClicked);

            SubscribeToStoryManager();

            PlayIdleAnimation();
        }

        private void Start()
        {
            // OnEnable 的调用顺序可能早于 StoryManager.Awake；Start 时再次同步，
            // 确保首次进入 MenuScene 也能应用 Inspector 中配置的默认 Helper。
            SubscribeToStoryManager();
        }

        private void OnDisable()
        {
            if (helperButton != null)
                helperButton.onClick.RemoveListener(HandleHelperClicked);
            UnsubscribeFromStoryManager();

            KillAndRestoreMotion();
            CloseActiveTalk();
        }

        private void OnDestroy()
        {
            _idleSequence?.Kill();
            _clickSequence?.Kill();
        }

        /// <summary>点击 Helper 的统一入口：播放反馈后创建一条新的专属气泡。</summary>
        private void HandleHelperClicked()
        {
            if (Time.unscaledTime < _nextClickTime)
                return;

            _nextClickTime = Time.unscaledTime + clickCooldown;
            PlayClickAnimation();
            TryCreateRandomTalk();
        }

        /// <summary>
        /// 从当前 Helper 对话池按条件和权重抽取文本，并实例化一个新的 HelperTalk。
        /// </summary>
        private void TryCreateRandomTalk()
        {
            StoryHelperData helperData = StoryManager.instance != null
                ? StoryManager.instance.ActiveHelperData
                : null;
            if (helperData == null)
            {
                Debug.LogWarning("[StoryHelper] 未配置当前 StoryHelperData，无法创建 HelperTalk。", this);
                return;
            }

            if (helperTalkPrefab == null)
            {
                Debug.LogWarning("[StoryHelper] 未配置 HelperTalk Prefab，无法创建 Helper 对话气泡。", this);
                return;
            }

            StoryHelperDialogueDefinition dialogue = SelectDialogue(helperData);
            string contentKey = dialogue != null ? dialogue.dialogueKey : helperData.fallbackDialogueKey;
            if (string.IsNullOrEmpty(contentKey))
            {
                Debug.LogWarning($"[StoryHelper] Helper '{helperData.name}' 没有可用候选对话，也未配置 Fallback Dialogue Key。", this);
                return;
            }

            if (dialogue != null)
                _lastDialogueId = GetDialogueIdentity(dialogue);

            CloseActiveTalk();
            _activeTalk = Instantiate(helperTalkPrefab, helperTalkContainer);
            _activeTalk.Closed += HandleTalkClosed;
            _activeTalk.Show(
                GetLocalizedText(helperData, helperData.displayNameKey, helperData.name),
                GetLocalizedText(helperData, contentKey, contentKey));
        }

        /// <summary>
        /// 构建当前可用候选池；当存在其它候选时，排除与上一条相同的台词，避免连续重复。
        /// </summary>
        private StoryHelperDialogueDefinition SelectDialogue(StoryHelperData helperData)
        {
            _eligibleDialogues.Clear();
            if (helperData.dialoguePool == null)
                return null;

            foreach (StoryHelperDialogueDefinition dialogue in helperData.dialoguePool)
            {
                if (dialogue == null || string.IsNullOrEmpty(dialogue.dialogueKey) || !IsDialogueAvailable(dialogue))
                    continue;

                _eligibleDialogues.Add(dialogue);
            }

            if (_eligibleDialogues.Count == 0)
                return null;

            bool hasAlternative = false;
            foreach (StoryHelperDialogueDefinition dialogue in _eligibleDialogues)
            {
                if (GetDialogueIdentity(dialogue) != _lastDialogueId)
                {
                    hasAlternative = true;
                    break;
                }
            }

            int totalWeight = 0;
            foreach (StoryHelperDialogueDefinition dialogue in _eligibleDialogues)
            {
                if (hasAlternative && GetDialogueIdentity(dialogue) == _lastDialogueId)
                    continue;

                totalWeight += Mathf.Max(1, dialogue.weight);
            }

            int randomWeight = UnityEngine.Random.Range(0, totalWeight);
            foreach (StoryHelperDialogueDefinition dialogue in _eligibleDialogues)
            {
                if (hasAlternative && GetDialogueIdentity(dialogue) == _lastDialogueId)
                    continue;

                randomWeight -= Mathf.Max(1, dialogue.weight);
                if (randomWeight < 0)
                    return dialogue;
            }

            return _eligibleDialogues[0];
        }

        /// <summary>
        /// 复用 StoryCondition 的通用条件树。未配置条件代表始终可用；已配置条件必须在当前已构建章节中求值，
        /// 以避免全局 Helper 在没有章节上下文时误读其它章节的 Block 状态。
        /// </summary>
        private static bool IsDialogueAvailable(StoryHelperDialogueDefinition dialogue)
        {
            StoryCondition condition = dialogue.availabilityCondition;
            if (condition == null || !condition.IsConfigured)
                return true;

            StoryTreeController treeController = StoryManager.instance != null
                ? StoryManager.instance.treeController
                : null;
            if (treeController == null || treeController.ActiveStoryData == null)
                return false;

            return condition.IsSatisfied((str) => StoryVariables.GetInt(str), treeController.IsBlockCompleted);
        }

        private static string GetDialogueIdentity(StoryHelperDialogueDefinition dialogue)
        {
            return string.IsNullOrEmpty(dialogue.dialogueId) ? dialogue.dialogueKey : dialogue.dialogueId;
        }

        /// <summary>
        /// 创建不影响点击节点的轻微循环漂浮。Idle 与 Click 使用不同节点，避免 DOTween 同时写入
        /// 同一个位置或缩放属性造成跳动。
        /// </summary>
        private void PlayIdleAnimation()
        {
            if (idleRoot == null || idleFloatDistance <= 0f)
                return;

            _idleSequence?.Kill();
            idleRoot.anchoredPosition = _idleBasePosition;
            _idleSequence = DOTween.Sequence()
                .Pause()
                .SetUpdate(true)
                .Append(idleRoot.DOAnchorPosY(_idleBasePosition.y + idleFloatDistance, idleHalfDuration).SetEase(Ease.InOutSine))
                .Append(idleRoot.DOAnchorPosY(_idleBasePosition.y - idleFloatDistance, idleHalfDuration * 2f).SetEase(Ease.InOutSine))
                .Append(idleRoot.DOAnchorPosY(_idleBasePosition.y, idleHalfDuration).SetEase(Ease.InOutSine))
                .SetLoops(-1);
            _idleSequence.Play();
        }

        /// <summary>播放一次克制的点击反馈，不会中断 Helper 的循环漂浮动画。</summary>
        private void PlayClickAnimation()
        {
            if (clickRoot == null)
                return;

            _clickSequence?.Kill();
            clickRoot.anchoredPosition = _clickBasePosition;
            clickRoot.localScale = _clickBaseScale;
            _clickSequence = DOTween.Sequence()
                .Pause()
                .SetUpdate(true)
                .Join(clickRoot.DOPunchScale(Vector3.one * clickPunchScale, clickPunchDuration, 5, 0.7f))
                .Join(clickRoot.DOPunchAnchorPos(Vector2.up * clickPunchOffset, clickPunchDuration, 5, 0.7f));
            _clickSequence.Play();
        }

        private void HandleActiveHelperChanged(StoryHelperData helperData)
        {
            _lastDialogueId = null;
            ApplyHelper(helperData);
            CloseActiveTalk();
        }

        /// <summary>
        /// Helper 与 StoryManager 的 Awake 顺序不固定；OnEnable 与 Start 都调用本方法，
        /// 确保首次进入场景时既能应用默认 Helper，也能为未来的 Helper 切换保留可靠事件入口。
        /// </summary>
        private void SubscribeToStoryManager()
        {
            StoryManager manager = StoryManager.instance;
            if (manager == null || _subscribedStoryManager == manager)
                return;

            UnsubscribeFromStoryManager();
            _subscribedStoryManager = manager;
            _subscribedStoryManager.ActiveHelperChanged += HandleActiveHelperChanged;
            ApplyHelper(_subscribedStoryManager.ActiveHelperData);
        }

        private void UnsubscribeFromStoryManager()
        {
            if (_subscribedStoryManager == null)
                return;

            _subscribedStoryManager.ActiveHelperChanged -= HandleActiveHelperChanged;
            _subscribedStoryManager = null;
        }

        private void ApplyHelper(StoryHelperData helperData)
        {
            if (_appliedHelperData == helperData)
                return;

            _appliedHelperData = helperData;
            visualPresenter?.ApplyHelper(helperData);
        }

        /// <summary>本地化失败时显示 Key，确保测试阶段仍能定位缺失条目，而不是得到空白气泡。</summary>
        private string GetLocalizedText(StoryHelperData helperData, string key, string fallback)
        {
            if (string.IsNullOrEmpty(key))
                return fallback;

            try
            {
                string localized = LocalizationSettings.StringDatabase.GetLocalizedString(helperData.localizationTable, key);
                return string.IsNullOrEmpty(localized) ? fallback : localized;
            }
            catch (Exception exception)
            {
                Debug.LogWarning($"[StoryHelper] 无法本地化 Key '{key}'，将回退显示 '{fallback}'。{exception.Message}", this);
                return fallback;
            }
        }

        private void CacheBaseTransforms()
        {
            if (idleRoot != null)
                _idleBasePosition = idleRoot.anchoredPosition;
            if (clickRoot != null)
            {
                _clickBasePosition = clickRoot.anchoredPosition;
                _clickBaseScale = clickRoot.localScale;
            }
        }

        private void KillAndRestoreMotion()
        {
            _idleSequence?.Kill();
            _clickSequence?.Kill();
            _idleSequence = null;
            _clickSequence = null;

            if (idleRoot != null)
                idleRoot.anchoredPosition = _idleBasePosition;
            if (clickRoot != null)
            {
                clickRoot.anchoredPosition = _clickBasePosition;
                clickRoot.localScale = _clickBaseScale;
            }
        }

        private void CloseActiveTalk()
        {
            if (_activeTalk == null)
                return;

            _activeTalk.Closed -= HandleTalkClosed;
            _activeTalk.CloseImmediately();
            _activeTalk = null;
        }

        private void HandleTalkClosed(StoryHelperTalk talk)
        {
            talk.Closed -= HandleTalkClosed;
            if (_activeTalk == talk)
                _activeTalk = null;
        }
    }
}