using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using TMPro;
using BaseGames.Core;
using BaseGames.Core.Events;
using BaseGames.Localization;
using BaseGames.Quest;
using QuestStateEnum = BaseGames.Core.Events.QuestState;

namespace BaseGames.UI.Inventory
{
    /// <summary>
    /// 全屏任务日志 Tab（Journal/Quests 分栏）。
    /// 左侧列出进行中 / 已完成任务，右侧详情显示选中任务的名称、描述与目标进度。
    ///
    /// 数据来源：ServiceLocator 获取 <see cref="IQuestManager"/>，读取 GetQuestsInState 快照。
    /// 与 HUD 的 <see cref="BaseGames.UI.HUD.QuestTrackerWidget"/> 不同：后者只显示当前追踪任务，
    /// 本面板提供完整列表浏览。本地化统一使用 Quest 表。
    /// </summary>
    public class QuestLogPanel : MonoBehaviour, IFocusable
    {
        [Header("任务列表")]
        [SerializeField] private Transform _listContainer;
        [Tooltip("任务行模板（含 Button + TMP_Text），kept inactive。")]
        [SerializeField] private Button    _rowTemplate;

        [Header("详情")]
        [SerializeField] private TMP_Text  _detailTitle;
        [SerializeField] private TMP_Text  _detailDesc;
        [SerializeField] private Transform _objectiveContainer;
        [Tooltip("目标行模板（TMP_Text），kept inactive。")]
        [SerializeField] private TMP_Text  _objectiveRowTemplate;
        [Tooltip("无进行中任务时的提示节点。")]
        [SerializeField] private GameObject _emptyHint;

        [Header("Event Channels - 刷新触发（任一即重建）")]
        [SerializeField] private QuestStateChangedEventChannel _onQuestStateChanged;

        private IQuestManager _quests;
        private readonly List<string>     _activeIds   = new();
        private readonly List<Button>     _rows        = new();
        private readonly Queue<Button>    _rowPool     = new();
        private readonly List<TMP_Text>   _objRows     = new();
        private readonly Queue<TMP_Text>  _objPool     = new();
        private string _selectedQuestId;
        private readonly CompositeDisposable _subs = new();

        private void Awake()
        {
            if (_rowTemplate != null) _rowTemplate.gameObject.SetActive(false);
            if (_objectiveRowTemplate != null) _objectiveRowTemplate.gameObject.SetActive(false);
        }

        private void OnEnable()
        {
            _quests = ServiceLocator.GetOrDefault<IQuestManager>();
            _onQuestStateChanged?.Subscribe(OnStateChanged).AddTo(_subs);
            Rebuild();
        }

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

        private void OnStateChanged(QuestStateChangedEvent _) => Rebuild();

        // ── 列表重建 ──────────────────────────────────────────────────────────
        private void Rebuild()
        {
            RecycleRows();
            if (_quests == null || _listContainer == null || _rowTemplate == null) return;

            _activeIds.Clear();
            CollectInto(QuestStateEnum.Active);
            CollectInto(QuestStateEnum.Completed);

            if (_emptyHint != null) _emptyHint.SetActive(_activeIds.Count == 0);

            foreach (var id in _activeIds)
            {
                var row = SpawnRow();
                BindRow(row, id);
                _rows.Add(row);
            }

            if (_activeIds.Count > 0) SelectQuest(_activeIds[0]);
            else ClearDetail();
        }

        private void CollectInto(QuestStateEnum state)
        {
            var snapshot = _quests.GetQuestsInState(state);
            for (int i = 0; i < snapshot.Count; i++)
                if (!_activeIds.Contains(snapshot[i])) _activeIds.Add(snapshot[i]);
        }

        private Button SpawnRow()
        {
            Button row = _rowPool.Count > 0 ? _rowPool.Dequeue() : Instantiate(_rowTemplate, _listContainer);
            row.transform.SetParent(_listContainer, false);
            row.gameObject.SetActive(true);
            return row;
        }

        private void BindRow(Button row, string questId)
        {
            var label = row.GetComponentInChildren<TMP_Text>(includeInactive: true);
            if (label != null) label.text = ResolveQuestTitle(questId);
            row.onClick.RemoveAllListeners();
            string captured = questId;
            row.onClick.AddListener(() => SelectQuest(captured));
        }

        private void RecycleRows()
        {
            foreach (var row in _rows)
            {
                if (row == null) continue;
                row.gameObject.SetActive(false);
                _rowPool.Enqueue(row);
            }
            _rows.Clear();
        }

        // ── 详情 ──────────────────────────────────────────────────────────────
        private void SelectQuest(string questId)
        {
            _selectedQuestId = questId;
            if (_quests == null || !_quests.TryGetQuest(questId, out var quest) || quest == null)
            {
                ClearDetail();
                return;
            }

            if (_detailTitle != null) _detailTitle.text = ResolveQuestTitle(questId);
            if (_detailDesc != null)
            {
                string loc = LocalizationManager.Get(quest.descriptionKey, LocalizationTable.Quest);
                _detailDesc.text = !string.IsNullOrEmpty(loc) && loc != quest.descriptionKey ? loc : string.Empty;
            }

            RebuildObjectives(quest);
        }

        private void RebuildObjectives(QuestSO quest)
        {
            RecycleObjectives();
            if (_objectiveContainer == null || _objectiveRowTemplate == null || quest.objectives == null) return;

            foreach (var obj in quest.objectives)
            {
                if (obj == null) continue;
                var row = _objPool.Count > 0 ? _objPool.Dequeue() : Instantiate(_objectiveRowTemplate, _objectiveContainer);
                row.transform.SetParent(_objectiveContainer, false);
                row.gameObject.SetActive(true);
                string loc = LocalizationManager.Get(obj.displayTextKey, LocalizationTable.Quest);
                row.text = !string.IsNullOrEmpty(loc) && loc != obj.displayTextKey ? loc : obj.displayTextKey;
                _objRows.Add(row);
            }
        }

        private void RecycleObjectives()
        {
            foreach (var row in _objRows)
            {
                if (row == null) continue;
                row.gameObject.SetActive(false);
                _objPool.Enqueue(row);
            }
            _objRows.Clear();
        }

        private void ClearDetail()
        {
            if (_detailTitle != null) _detailTitle.text = string.Empty;
            if (_detailDesc != null)  _detailDesc.text  = string.Empty;
            RecycleObjectives();
        }

        private string ResolveQuestTitle(string questId)
        {
            if (_quests != null && _quests.TryGetQuest(questId, out var quest) && quest != null
                && !string.IsNullOrEmpty(quest.displayNameKey))
            {
                string loc = LocalizationManager.Get(quest.displayNameKey, LocalizationTable.Quest);
                return !string.IsNullOrEmpty(loc) && loc != quest.displayNameKey ? loc : questId;
            }
            return questId;
        }

        // ── IFocusable ────────────────────────────────────────────────────────
        public void OnFocusRestored()
        {
            if (_rows.Count > 0 && _rows[0] != null)
                EventSystem.current?.SetSelectedGameObject(_rows[0].gameObject);
        }
    }
}