using System.Collections.Generic;
using Ichni.Story.Dialogue;
using TMPro;
using UnityEngine;
using UnityEngine.Localization;
using UnityEngine.UI;

namespace Ichni.Story.UI
{
    /// <summary>
    /// 文本块视图。点击后通过 Yarn Spinner 进入对应节点的对话。
    /// </summary>
    public class TextBlockView : StoryBlockView
    {
        [Header("Text Block")] 
        public TMP_Text storyIdText;
        public TMP_Text titleText;

        [Tooltip("各状态对应的背景预制体。未配置 Forbidden 时会自动回退到 Locked 背景。")]
        public Dictionary<StoryBlockState, GameObject> blockVisuals = new Dictionary<StoryBlockState, GameObject>();

        /// <summary>该文本块对应的 Yarn 节点名。</summary>
        public string YarnNodeName { get; private set; }

        // 当前已实例化的状态背景对象；状态切换时销毁并替换
        private GameObject _currentVisual;

        // 直接持有 StoryData 的 LocalizedString，并订阅其 StringChanged 回调。
        // Unity Localization 会在首次订阅和语言切换时自行异步刷新文本。
        private LocalizedString _titleReference;
        private bool _isTitleLocalizationSubscribed;

        private void OnEnable()
        {
            StartTitleLocalization();
        }

        private void OnDisable()
        {
            StopTitleLocalization();
        }

        public override void Initialize(StoryBlockDefinition def, Vector2 position, StoryBlockState blockState)
        {
            // 注意：base.Initialize 末尾会调用 ApplyState(state)，届时已生成对应背景
            YarnNodeName = def.yarnNodeName;

            base.Initialize(def, position, blockState);

            if (storyIdText != null)
                storyIdText.text = def.blockId;

            StopTitleLocalization();
            _titleReference = def.title;
            StartTitleLocalization();
        }

        /// <summary>
        /// 订阅当前 TextBlock 的 LocalizedString。无需手写 Table / Key 读取或监听全局 Locale，
        /// LocalizedString 会遵循 Unity 官方生命周期异步加载，并在语言变化后触发 StringChanged。
        /// </summary>
        private void StartTitleLocalization()
        {
            if (_isTitleLocalizationSubscribed || titleText == null)
                return;

            if (_titleReference == null || _titleReference.IsEmpty)
            {
                titleText.text = blockId;
                return;
            }

            _titleReference.StringChanged += ApplyLocalizedTitle;
            _isTitleLocalizationSubscribed = true;
        }

        private void StopTitleLocalization()
        {
            if (!_isTitleLocalizationSubscribed || _titleReference == null)
                return;

            _titleReference.StringChanged -= ApplyLocalizedTitle;
            _isTitleLocalizationSubscribed = false;
        }

        private void ApplyLocalizedTitle(string localizedTitle)
        {
            if (titleText != null)
                titleText.text = string.IsNullOrEmpty(localizedTitle) ? blockId : localizedTitle;
        }

        /// <summary>
        /// 应用状态：在基类逻辑（按钮可交互性）之外，切换到对应状态的背景视觉。
        /// </summary>
        public override void ApplyState(StoryBlockState newState)
        {
            base.ApplyState(newState);
            UpdateVisual(newState);
        }

        /// <summary>
        /// 按当前状态实例化对应的背景预制体，作为第一个子物体（位于文本/端口/按钮之下），
        /// 并拉伸铺满整个 block。状态切换时先销毁旧背景。
        /// </summary>
        private void UpdateVisual(StoryBlockState newState)
        {
            if (_currentVisual != null)
            {
                // 旧背景中的 Button 即将被销毁，先主动解绑，防止基类继续持有失效引用。
                BindInteractionButton(null);
                Destroy(_currentVisual);
                _currentVisual = null;
            }

            if (blockVisuals == null)
            {
                Debug.LogWarning($"[TextBlockView] block '{blockId}' 缺少状态 {newState} 的背景预制体（blockVisuals 未配置）。");
                return;
            }

            // Forbidden 专用美术尚未配置前沿用 Locked 背景，保证互斥路线 Block 始终可见且不可点击。
            // 后续只需在 Inspector 中补充 Forbidden 键，即可自动覆盖此回退表现。
            if ((!blockVisuals.TryGetValue(newState, out GameObject prefab) || prefab == null) &&
                newState == StoryBlockState.Forbidden)
            {
                blockVisuals.TryGetValue(StoryBlockState.Locked, out prefab);
            }

            if (prefab == null)
            {
                Debug.LogWarning($"[TextBlockView] block '{blockId}' 缺少状态 {newState} 的背景预制体。");
                return;
            }

            _currentVisual = Instantiate(prefab, blockRect);
            _currentVisual.transform.SetAsFirstSibling();
            // 状态视觉可自由调整层级；不再依赖“第一个子物体就是 Button”的脆弱约定。
            // 通过基类重新绑定，确保每一次状态背景替换后 TextBlock 仍能响应点击。
            Button interactionButton = _currentVisual.GetComponentInChildren<Button>(true);
            if (interactionButton == null)
                Debug.LogWarning($"[TextBlockView] block '{blockId}' 的状态视觉 '{prefab.name}' 缺少 Button，无法点击。");
            BindInteractionButton(interactionButton);
            // 背景铺满整个 block
            if (_currentVisual.transform is RectTransform visualRect)
            {
                visualRect.anchorMin = Vector2.zero;
                visualRect.anchorMax = Vector2.one;
                visualRect.offsetMin = Vector2.zero;
                visualRect.offsetMax = Vector2.zero;
                visualRect.localScale = Vector3.one;
            }
        }

        protected override void OnClicked()
        {
            if (StoryDialogueController.instance == null)
            {
                Debug.LogWarning($"[TextBlockView] 场景中缺少 StoryDialogueController，无法播放 block '{blockId}' 的对话。");
                return;
            }

            StoryDialogueController.instance.PlayBlock(this);
        }
    }
}