using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using TMPro;
using BaseGames.Core;
using BaseGames.Core.Events;
using BaseGames.Quest;
using BaseGames.Localization;

namespace BaseGames.UI.HUD
{
    /// <summary>
    /// 任务追踪 HUD 控件（架构 10_UIModule §HUD）。
    /// 自动追踪最近开始的活跃任务，显示任务名称与各目标的完成进度。
    /// 订阅 QuestEventChannelRegistry 中的广播频道，实现响应式更新。
    ///
    /// Inspector 必填：
    ///   _questDatabase          — 注册到游戏中的所有 QuestSO 列表（与 QuestManager._allQuests 保持一致）
    ///   _questTitleText         — 显示任务标题的 TMP_Text
    ///   _objectiveRowTemplate   — 目标行模板（保持非激活状态，用于实例化）
    ///   _objectiveContainer     — 目标行父节点
    ///   事件频道字段            — 从 QuestEventChannelRegistry 对应字段拖入
    /// </summary>
    public class QuestTrackerWidget : MonoBehaviour
    {
        // ── Inspector 字段 ────────────────────────────────────────────────────

        [Header("UI 根节点")]
        [SerializeField] private TMP_Text   _questTitleText;
        [SerializeField] private GameObject _objectiveRowTemplate;  // kept inactive
        [SerializeField] private Transform  _objectiveContainer;

        [Header("Event Channels")]
        [Tooltip("EVT_QuestStarted：payload = questId")]
        [SerializeField] private StringEventChannelSO _onQuestStarted;
        [Tooltip("EVT_QuestCompleted：payload = questId")]
        [SerializeField] private StringEventChannelSO _onQuestCompleted;
        [Tooltip("EVT_QuestFailed：payload = questId")]
        [SerializeField] private StringEventChannelSO _onQuestFailed;
        [Tooltip("EVT_QuestAbandoned：payload = questId")]
        [SerializeField] private StringEventChannelSO _onQuestAbandoned;
        [Tooltip("EVT_QuestReadyToComplete：payload = questId")]
        [SerializeField] private StringEventChannelSO _onQuestReadyToComplete;
        [Tooltip("EVT_QuestObjectiveBatchUpdated：同帧内多目标聚合更新")]
        [SerializeField] private QuestObjectiveBatchEventChannelSO _onObjectiveBatchUpdated;

        // ── 私有状态 ──────────────────────────────────────────────────────────

        private string   _trackedQuestId;
        private QuestSO  _trackedQuest;
        private readonly List<GameObject>         _rowPool          = new();
        private readonly List<(TMP_Text label, TMP_Text progress)> _activeRows = new();
        private readonly CompositeDisposable      _subs             = new();

        // IQuestManager 在 OnEnable 时从 ServiceLocator 解析，消除对 _questDatabase 数组的重复注入需求
        private IQuestManager _questManager;

        // ── 进度字典：objectiveId → (Progress, Required) ─────────────────────

        private readonly Dictionary<string, (int Progress, int Required)> _progressCache =
            new(System.StringComparer.Ordinal);

        // ── 生命周期 ──────────────────────────────────────────────────────────

        private void Awake()
        {
            gameObject.SetActive(false);
        }

        private void OnEnable()
        {
            // 延迟解析而非缓存到字段：支持 ServiceLocator 中途替换实现（测试/多场景）
            _questManager = ServiceLocator.GetOrDefault<IQuestManager>();
            _onQuestStarted?.Subscribe(OnQuestStarted).AddTo(_subs);
            _onQuestCompleted?.Subscribe(OnQuestEnded).AddTo(_subs);
            _onQuestFailed?.Subscribe(OnQuestEnded).AddTo(_subs);
            _onQuestAbandoned?.Subscribe(OnQuestEnded).AddTo(_subs);
            _onQuestReadyToComplete?.Subscribe(OnQuestReadyToComplete).AddTo(_subs);
            _onObjectiveBatchUpdated?.Subscribe(OnObjectiveBatchUpdated).AddTo(_subs);
        }

        private void OnDisable()
        {
            _subs.Clear();
        }

        // ── 事件处理 ──────────────────────────────────────────────────────────

        private void OnQuestStarted(string questId)
        {
            // 自动追踪最新开始的任务
            _trackedQuestId = questId;
            // 通过 IQuestManager 接口查找 QuestSO，无需在 HUD 中重复注入数据库
            _questManager?.TryGetQuest(questId, out _trackedQuest);
            _progressCache.Clear();
            Rebuild();
        }

        private void OnQuestEnded(string questId)
        {
            if (questId != _trackedQuestId) return;
            _trackedQuestId = null;
            _trackedQuest   = null;
            _progressCache.Clear();
            gameObject.SetActive(false);
        }

        private void OnQuestReadyToComplete(string questId)
        {
            if (questId == _trackedQuestId)
            {
                // 可选：更改标题颜色以提示玩家交任务
                if (_questTitleText != null)
                    _questTitleText.color = Color.yellow;
            }
        }

        private void OnObjectiveBatchUpdated(QuestObjectiveBatchEvent batch)
        {
            if (batch.QuestId != _trackedQuestId) return;
            if (batch.Updates == null) return;

            foreach (var update in batch.Updates)
                _progressCache[update.ObjectiveId] = (update.Progress, update.Required);

            RefreshObjectiveRows();
        }

        // ── UI 重建 ───────────────────────────────────────────────────────────

        private void Rebuild()
        {
            if (string.IsNullOrEmpty(_trackedQuestId))
            {
                gameObject.SetActive(false);
                return;
            }

            gameObject.SetActive(true);

            // 标题
            if (_questTitleText != null)
            {
                _questTitleText.color = Color.white;
                if (_trackedQuest != null && !string.IsNullOrEmpty(_trackedQuest.displayNameKey))
                {
                    string title = LocalizationManager.Get(_trackedQuest.displayNameKey, LocalizationTable.Quest);
                    _questTitleText.text = string.IsNullOrEmpty(title) || title == _trackedQuest.displayNameKey
                        ? _trackedQuestId
                        : title;
                }
                else
                {
                    _questTitleText.text = _trackedQuestId;
                }
            }

            // 返还所有行到对象池
            foreach (var row in _activeRows)
                if (row.label != null) row.label.transform.parent.gameObject.SetActive(false);
            _activeRows.Clear();

            // 生成目标行
            if (_trackedQuest?.objectives == null) return;
            foreach (var obj in _trackedQuest.objectives)
            {
                if (obj == null) continue;

                var rowGo = GetOrCreateRow();
                var texts = rowGo.GetComponentsInChildren<TMP_Text>(includeInactive: true);
                TMP_Text labelText    = texts.Length > 0 ? texts[0] : null;
                TMP_Text progressText = texts.Length > 1 ? texts[1] : null;

                if (labelText != null)
                {
                    string objText = LocalizationManager.Get(obj.displayTextKey, LocalizationTable.Quest);
                    labelText.text = string.IsNullOrEmpty(objText) || objText == obj.displayTextKey
                        ? obj.objectiveId
                        : objText;
                }

                _progressCache.TryGetValue(obj.objectiveId, out var cached);
                int prog = cached.Progress;
                int req  = cached.Required > 0 ? cached.Required : obj.GetRequiredCount();
                if (progressText != null)
                    progressText.text = req > 1 ? $"{prog}/{req}" : string.Empty;

                rowGo.SetActive(true);
                _activeRows.Add((labelText, progressText));
            }
        }

        private void RefreshObjectiveRows()
        {
            if (_trackedQuest?.objectives == null) return;
            for (int i = 0; i < _activeRows.Count && i < _trackedQuest.objectives.Length; i++)
            {
                var obj = _trackedQuest.objectives[i];
                if (obj == null) continue;

                _progressCache.TryGetValue(obj.objectiveId, out var cached);
                int prog = cached.Progress;
                int req  = cached.Required > 0 ? cached.Required : obj.GetRequiredCount();

                var (_, progressText) = _activeRows[i];
                if (progressText != null)
                    progressText.text = req > 1 ? $"{prog}/{req}" : string.Empty;
            }
        }

        // ── 对象池 ────────────────────────────────────────────────────────────

        private GameObject GetOrCreateRow()
        {
            foreach (var r in _rowPool)
                if (r != null && !r.activeSelf) return r;

            var go = Instantiate(_objectiveRowTemplate, _objectiveContainer);
            _rowPool.Add(go);
            return go;
        }
    }
}