using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using BaseGames.Core;
using BaseGames.Core.Assets;
using BaseGames.Core.Events;
using BaseGames.UI;
using BaseGames.UI.Menus;

namespace BaseGames.UI.MainMenu
{
    /// <summary>
    /// 数据驱动主菜单控制器（表驱动按钮列表 + 子面板编排）。
    ///
    /// 按钮列表据 <see cref="MainMenuConfigSO"/> 生成（标签/图标/顺序/动作纯数据，策划改表零代码）。
    /// 子面板（存档槽 / 设置 / 制作人员）经统一 <see cref="IUINavigator"/> 压栈：栈式回退、ESC 逐层关闭、
    /// 焦点恢复均由导航器负责，本控制器不再自管取消键与面板显隐。主按钮组作为"栈底上下文"
    /// （不入栈），据 <see cref="IUINavigator.Depth"/> 在有子面板打开时屏蔽自身交互。
    /// </summary>
    public class DataDrivenMainMenuController : MonoBehaviour
    {
        [Header("数据表 / 按钮列表")]
        [SerializeField] private MainMenuConfigSO   _config;
        [Tooltip("按钮的父节点（通常挂 VerticalLayoutGroup，即主按钮组）。")]
        [SerializeField] private Transform          _container;
        [SerializeField] private MainMenuButtonView _buttonPrefab;

        [Header("主按钮组（入场动画 / 栈底屏蔽）")]
        [SerializeField] private CanvasGroup   _mainButtonsGroup;
        [SerializeField] private RectTransform _mainButtonsRect;

        [Header("子面板（导航器压栈对象，整面板根须挂 UIPanelBase）")]
        [SerializeField] private SaveSlotController _saveSlotPanel;
        [Tooltip("设置面板根（UISimplePanel；内含数据驱动设置实例）。")]
        [SerializeField] private UIPanelBase        _settingsPanel;
        [Tooltip("制作人员面板根（UISimplePanel）。")]
        [SerializeField] private UIPanelBase        _creditsPanel;

        [Header("子面板关闭按钮（可选，等价于 ESC：出栈一层）")]
        [SerializeField] private UnityEngine.UI.Button _btnCloseSaveSlot;
        [SerializeField] private UnityEngine.UI.Button _btnCloseSettings;
        [SerializeField] private UnityEngine.UI.Button _btnCloseCredits;

        [Header("入场动画")]
        [SerializeField] private float _entrySlideOffset = 80f;
        [SerializeField] private float _entryDuration    = 0.55f;

        [Header("场景")]
        [SerializeField] private string _firstGameSceneKey = AddressKeys.SceneGameChapter1;

        [Header("Event Channels - Listen")]
        [SerializeField] private GameStateEventChannelSO _onGameStateChanged;
        [SerializeField] private IntEventChannelSO       _onSlotConfirmed;

        [Header("Event Channels - Raise")]
        [SerializeField] private SceneLoadRequestEventChannelSO _onSceneLoadRequest;

        private readonly CompositeDisposable _subs = new();
        private readonly List<(MainMenuConfigSO.Item item, MainMenuButtonView view)> _buttons = new();
        private Vector2 _buttonsPanelOriginalPos;
        private MainMenuButtonView _firstButton;
        private IUINavigator _nav;

        // ── 生命周期 ──────────────────────────────────────────────────────────
        private void Awake()
        {
            if (_mainButtonsRect != null)
                _buttonsPanelOriginalPos = _mainButtonsRect.anchoredPosition;

            _btnCloseSaveSlot?.onClick.AddListener(() => Nav?.Pop());
            _btnCloseSettings?.onClick.AddListener(() => Nav?.Pop());
            _btnCloseCredits? .onClick.AddListener(() => Nav?.Pop());

            SetButtonsGroupVisible(false);
            BuildMenu();
        }

        private void OnEnable()
        {
            _onGameStateChanged?.Subscribe(HandleGameStateChanged).AddTo(_subs);
            _onSlotConfirmed?   .Subscribe(HandleSlotConfirmed).AddTo(_subs);

            _nav = ServiceLocator.GetOrDefault<IUINavigator>();
            if (_nav != null) _nav.StackChanged += HandleStackChanged;
        }

        private void OnDisable()
        {
            _subs.Clear();
            if (_nav != null) _nav.StackChanged -= HandleStackChanged;
        }

        private void Start() => StartCoroutine(PlayEntryAnimation());

        // ── 据表建菜单 ────────────────────────────────────────────────────────
        /// <summary>据配置重建主菜单按钮列表（public 以便编辑器/测试验证）。</summary>
        public void BuildMenu()
        {
            ClearMenu();
            if (_config == null || _container == null || _buttonPrefab == null) return;

            foreach (var item in _config.Items)
            {
                var view = Instantiate(_buttonPrefab, _container);
                view.gameObject.SetActive(true);
                var captured = item;
                view.Bind(item.labelKey, item.icon, () => Dispatch(captured));
                _buttons.Add((item, view));
                if (_firstButton == null) _firstButton = view;
            }

            RefreshConditional();
        }

        /// <summary>清空菜单按钮（容器全部子节点）。编辑器预览与运行时重建共用。</summary>
        public void ClearMenu()
        {
            _buttons.Clear();
            _firstButton = null;
            if (_container == null) return;
            for (int i = _container.childCount - 1; i >= 0; i--)
            {
                var child = _container.GetChild(i).gameObject;
                if (Application.isPlaying) Destroy(child);
                else DestroyImmediate(child);
            }
        }

        /// <summary>根据存档存在性刷新 requiresSave 按钮的可用性（如"继续"）。</summary>
        public void RefreshConditional()
        {
            bool hasSave = HasAnySave();
            foreach (var (item, view) in _buttons)
                if (item.requiresSave && view != null)
                    view.SetInteractable(hasSave);
        }

        // ── 动作派发 ──────────────────────────────────────────────────────────
        private void Dispatch(MainMenuConfigSO.Item item)
        {
            switch (item.action)
            {
                case MainMenuAction.NewGame:
                    if (_saveSlotPanel != null) { _saveSlotPanel.SetMode(SaveSlotPanelMode.NewGame); Nav?.Push(_saveSlotPanel); }
                    break;
                case MainMenuAction.Continue:
                    if (_saveSlotPanel != null) { _saveSlotPanel.SetMode(SaveSlotPanelMode.Continue); Nav?.Push(_saveSlotPanel); }
                    break;
                case MainMenuAction.OpenSettings:
                    if (_settingsPanel != null) Nav?.Push(_settingsPanel);
                    break;
                case MainMenuAction.OpenCredits:
                    if (_creditsPanel != null) Nav?.Push(_creditsPanel);
                    break;
                case MainMenuAction.LoadScene:
                    _onSceneLoadRequest?.Raise(new SceneLoadRequest
                    {
                        SceneName         = string.IsNullOrEmpty(item.sceneKey) ? _firstGameSceneKey : item.sceneKey,
                        TransitionType    = TransitionType.Scene,
                    });
                    break;
                case MainMenuAction.Quit:
                    Application.Quit();
                    break;
                case MainMenuAction.RaiseEvent:
                    item.eventChannel?.Raise();
                    break;
            }
        }

        // ── 栈底按钮组屏蔽（有子面板打开时禁用主按钮，避免方向键穿透）──────────
        private IUINavigator Nav => _nav ??= ServiceLocator.GetOrDefault<IUINavigator>();

        private void HandleStackChanged()
        {
            bool anyOpen = Nav != null && Nav.Depth > 0;
            if (_mainButtonsGroup != null)
            {
                _mainButtonsGroup.interactable   = !anyOpen;
                _mainButtonsGroup.blocksRaycasts = !anyOpen;
            }
            if (!anyOpen && _firstButton != null)
                EventSystem.current?.SetSelectedGameObject(_firstButton.Button.gameObject);
        }

        // ── 存档槽确认 ────────────────────────────────────────────────────────
        private void HandleSlotConfirmed(int _)
        {
            Nav?.PopToRoot();   // 关闭存档槽（及其上任何子对话框），准备进场景

            var svc = ServiceLocator.GetOrDefault<ISaveService>();
            string checkpointScene = svc?.LastCheckpointScene;
            bool   hasCheckpoint   = !string.IsNullOrEmpty(checkpointScene);

            _onSceneLoadRequest?.Raise(new SceneLoadRequest
            {
                SceneName         = hasCheckpoint ? checkpointScene : _firstGameSceneKey,
                EntryTransitionId = hasCheckpoint ? svc.LastCheckpointSpawnId : null,
                TransitionType    = TransitionType.Scene,
            });
        }

        private void HandleGameStateChanged(GameStateId state)
        {
            bool isMainMenu = state == GameStates.MainMenu;
            if (_mainButtonsGroup != null && Nav != null && Nav.Depth == 0)
            {
                _mainButtonsGroup.interactable   = isMainMenu;
                _mainButtonsGroup.blocksRaycasts = isMainMenu;
            }
        }

        // ── 入场动画 ──────────────────────────────────────────────────────────
        private IEnumerator PlayEntryAnimation()
        {
            if (_mainButtonsGroup == null) yield break;

            Vector2 startPos = _buttonsPanelOriginalPos - new Vector2(0f, _entrySlideOffset);
            if (_mainButtonsRect != null) _mainButtonsRect.anchoredPosition = startPos;

            float elapsed = 0f;
            while (elapsed < _entryDuration)
            {
                float t = Mathf.SmoothStep(0f, 1f, elapsed / _entryDuration);
                _mainButtonsGroup.alpha = t;
                if (_mainButtonsRect != null)
                    _mainButtonsRect.anchoredPosition = Vector2.Lerp(startPos, _buttonsPanelOriginalPos, t);
                elapsed += Time.unscaledDeltaTime;
                yield return null;
            }

            _mainButtonsGroup.alpha = 1f;
            if (_mainButtonsRect != null) _mainButtonsRect.anchoredPosition = _buttonsPanelOriginalPos;
            _mainButtonsGroup.interactable   = true;
            _mainButtonsGroup.blocksRaycasts = true;

            if (_firstButton != null)
                EventSystem.current?.SetSelectedGameObject(_firstButton.Button.gameObject);
        }

        // ── 工具 ──────────────────────────────────────────────────────────────
        private static bool HasAnySave()
        {
            var s = ServiceLocator.GetOrDefault<ISaveService>();
            return s != null && (s.HasSave(0) || s.HasSave(1) || s.HasSave(2));
        }

        private void SetButtonsGroupVisible(bool visible)
        {
            if (_mainButtonsGroup == null) return;
            _mainButtonsGroup.alpha          = visible ? 1f : 0f;
            _mainButtonsGroup.interactable   = visible;
            _mainButtonsGroup.blocksRaycasts = visible;
        }
    }
}