using System.Collections.Generic;
using TMPro;
using UnityEngine;
using UnityEngine.InputSystem;
using Sirenix.OdinInspector;

namespace SLSUtilities.Narrative.UI
{
    /// <summary>
    /// 选项悬停提示面板管理器。
    /// - 鼠标模式：仅在鼠标悬停于选项"文本区域"（非空白行区域）时显示，跟随鼠标移动。
    /// - 键盘模式：在选项文本的右上角处固定显示。
    /// - 支持右键固定和点击外部关闭。
    /// </summary>
    public class OptionTooltipUI : MonoBehaviour
    {
        public static OptionTooltipUI Instance { get; private set; }

        [TitleGroup("核心引用 (Core References)", Alignment = TitleAlignments.Centered)]

        [BoxGroup("核心引用 (Core References)/UI")]
        [Required("需要指定 Tooltip 面板的 Prefab（必须挂载 TooltipPanel 组件）")]
        [SerializeField] private GameObject tooltipPanelPrefab;

        [BoxGroup("核心引用 (Core References)/UI")]
        [Required("Tooltip 生成的父级容器（RectTransform）")]
        [SerializeField] private RectTransform tooltipContainer;

        [BoxGroup("核心引用 (Core References)/UI")]
        [Tooltip("渲染 Canvas 的摄像机。Screen Space Overlay 模式下留空")]
        [SerializeField] private Camera uiCamera;

        [TitleGroup("行为设置 (Behavior Settings)", Alignment = TitleAlignments.Centered)]
        [BoxGroup("行为设置 (Behavior Settings)/定位")]
        [Tooltip("Tooltip 左下角相对于鼠标（或键盘时文本右上角）的像素偏移量")]
        [SerializeField] private Vector2 tooltipOffset = new Vector2(12f, 12f);

        [BoxGroup("行为设置 (Behavior Settings)/定位")]
        [Tooltip("鼠标检测的边缘容差像素数。\n较大值可避免中文全角标点符号边缘闪烁，较小值则更精确地限制在文字内。")]
        [Range(0f, 20f)]
        [SerializeField] private float textBoundsTolerance = 6f;

        private TooltipPanel _hoverPanel;
        private AdvancedOptionItem _hoverItem;

        // 当前悬停是否由鼠标触发（false = 键盘触发）
        private bool _isMouseSelection;

        // 已固定的选项 Tooltip
        private readonly List<TooltipPanel> _pinnedPanels = new List<TooltipPanel>();

        private void Awake()
        {
            Instance = this;
        }

        private void OnDisable()
        {
            CloseHoverPanel();
            CloseAllPinnedPanels();
        }

        private void Update()
        {
            HandleHoverPanelVisibility();
            HandleClickInput();
        }

        // ---------------------------------------------------------------
        // 公开接口（由 AdvancedOptionItem 调用）
        // ---------------------------------------------------------------

        public void OnOptionSelected(AdvancedOptionItem item, bool isMouseTriggered)
        {
            _hoverItem = item;
            _isMouseSelection = isMouseTriggered;

            string textToShow = item.Option.IsAvailable ? item.TooltipDesc : item.TooltipFail;
            if (string.IsNullOrWhiteSpace(textToShow))
            {
                CloseHoverPanel();
                return;
            }

            if (HasPinnedPanelForOption(textToShow))
            {
                CloseHoverPanel();
                return;
            }

            CloseHoverPanel();
            _hoverPanel = SpawnPanel(textToShow);

            if (_isMouseSelection)
            {
                // 鼠标模式：初始位置对齐鼠标，后续每帧跟随
                Vector2 mousePos = Mouse.current.position.ReadValue();
                _hoverPanel.PositionAtScreenPoint(mousePos, tooltipOffset);
            }
            else
            {
                // 键盘模式：定位在文本右上角处
                PositionPanelAtTextTopRight(_hoverPanel, item.GetTextComponent());
            }
        }

        public void OnOptionDeselected(AdvancedOptionItem item)
        {
            if (_hoverItem == item)
                CloseHoverPanel();
        }

        // ---------------------------------------------------------------
        // 每帧更新（悬停面板可见性与定位）
        // ---------------------------------------------------------------

        private void HandleHoverPanelVisibility()
        {
            if (_hoverPanel == null) return;

            // 当选项文本中出现了关键词且玩家正在选中关键词时，隐去未固定的选项 Tooltip
            bool isHoveringKeyword = KeywordTooltipUI.Instance != null && KeywordTooltipUI.Instance.HasHoverPanel;
            if (isHoveringKeyword)
            {
                _hoverPanel.gameObject.SetActive(false);
                return;
            }

            if (_isMouseSelection)
            {
                Vector2 mousePos = Mouse.current.position.ReadValue();

                // 使用 textBounds 检测文本渲染边界，避免全角标点符号字形间隙造成闪烁
                var textComp = _hoverItem?.GetTextComponent();
                bool mouseOverText = IsMouseOverTextArea(textComp, mousePos);

                if (mouseOverText)
                {
                    _hoverPanel.gameObject.SetActive(true);
                    // 每帧跟随鼠标
                    _hoverPanel.PositionAtScreenPoint(mousePos, tooltipOffset);
                }
                else
                {
                    _hoverPanel.gameObject.SetActive(false);
                }
            }
            else
            {
                // 键盘模式：始终显示，位置固定在文本右上角（无需每帧更新）
                _hoverPanel.gameObject.SetActive(true);
            }
        }

        // ---------------------------------------------------------------
        // 点击输入处理
        // ---------------------------------------------------------------

        private void HandleClickInput()
        {
            bool leftClick = Mouse.current.leftButton.wasPressedThisFrame;
            bool rightClick = Mouse.current.rightButton.wasPressedThisFrame;

            if (!leftClick && !rightClick) return;

            Vector2 mousePos = Mouse.current.position.ReadValue();

            // 右键固定：当 hover panel 可见时，右键单击在选项区域内将其固定
            if (rightClick && _hoverPanel != null && _hoverPanel.gameObject.activeSelf)
            {
                bool isHoveringKeyword = KeywordTooltipUI.Instance != null && KeywordTooltipUI.Instance.HasHoverPanel;
                if (!isHoveringKeyword)
                {
                    // 使用与悬停检测相同的 textBounds 方式
                    var textComp = _hoverItem?.GetTextComponent();
                    bool clickOverText = IsMouseOverTextArea(textComp, mousePos);
                    bool clickOverPanel = _hoverPanel.ContainsScreenPoint(mousePos, uiCamera);

                    if (clickOverText || clickOverPanel)
                    {
                        PinHoverPanel();
                        return;
                    }
                }
            }

            // 点击外部关闭所有已固定的选项 Tooltip
            if (_pinnedPanels.Count > 0)
            {
                bool clickedInside = false;

                foreach (var panel in _pinnedPanels)
                {
                    if (panel.ContainsScreenPoint(mousePos, uiCamera))
                    {
                        clickedInside = true;
                        break;
                    }
                }

                if (!clickedInside && _hoverPanel != null && _hoverPanel.ContainsScreenPoint(mousePos, uiCamera))
                    clickedInside = true;

                if (!clickedInside)
                    CloseAllPinnedPanels();
            }
        }

        // ---------------------------------------------------------------
        // 面板生命周期
        // ---------------------------------------------------------------

        private void PinHoverPanel()
        {
            if (_hoverPanel == null) return;

            _hoverPanel.Pin();
            _pinnedPanels.Add(_hoverPanel);
            _hoverPanel = null;
        }

        private TooltipPanel SpawnPanel(string description)
        {
            if (tooltipPanelPrefab == null || tooltipContainer == null) return null;

            var panelGO = Instantiate(tooltipPanelPrefab, tooltipContainer);
            var panel = panelGO.GetComponent<TooltipPanel>();

            // 创建临时 KeywordData，内容为选项说明（无标题）
            var data = ScriptableObject.CreateInstance<KeywordData>();
            data.keyword = string.Empty;
            // 选项说明中也支持嵌套关键词：由 Initialize 内的 ProcessDescription 自动处理
            data.description = description;

            panel.Initialize(data, false);

            Destroy(data);
            return panel;
        }

        // ---------------------------------------------------------------
        // 定位工具
        // ---------------------------------------------------------------

        /// <summary>
        /// 将面板定位在 TMP 文本组件的右上角处（用于键盘模式）。
        /// </summary>
        private void PositionPanelAtTextTopRight(TooltipPanel panel, TMP_Text textComp)
        {
            if (panel == null || textComp == null) return;

            Vector3[] corners = new Vector3[4];
            textComp.rectTransform.GetWorldCorners(corners);
            // corners 顺序：0=BL, 1=TL, 2=TR, 3=BR（屏幕坐标，Overlay模式）
            // 对于非 Overlay 模式，使用 WorldToScreenPoint 转换
            Vector2 screenPos = uiCamera != null
                ? RectTransformUtility.WorldToScreenPoint(uiCamera, corners[2])
                : new Vector2(corners[2].x, corners[2].y);

            panel.PositionAtScreenPoint(screenPos, tooltipOffset);
        }

        // ---------------------------------------------------------------
        // 文本区域检测工具
        // ---------------------------------------------------------------

        /// <summary>
        /// 检测鼠标屏幕坐标是否处于 TMP 文本的实际渲染边界矩形内。
        /// 使用 textBounds（字形渲染包围盒）而非 FindIntersectingCharacter，
        /// 可避免中文全角标点符号字形内空白区域导致的闪烁问题。
        /// </summary>
        private bool IsMouseOverTextArea(TMP_Text textComp, Vector2 screenMousePos)
        {
            if (textComp == null) return false;

            // 确保 TMPro 网格在当下完成同步刷新，以获得 100% 准确的渲染包围盒，彻底阻断首帧零包围盒渲染计算闪烁
            textComp.ForceMeshUpdate();

            // 将屏幕坐标转换为 TMP RectTransform 的局部坐标
            if (!RectTransformUtility.ScreenPointToLocalPointInRectangle(
                    textComp.rectTransform, screenMousePos, uiCamera, out Vector2 localPoint))
                return false;

            // textBounds 是 TMP 实际渲染内容的包围盒（局部坐标），
            // 比 RectTransform 本身更精确，且不受字符个体差异影响
            Bounds bounds = textComp.textBounds;

            // 加入可配置容差，避免全角标点字形边缘闪烁
            return localPoint.x >= bounds.min.x - textBoundsTolerance
                && localPoint.x <= bounds.max.x + textBoundsTolerance
                && localPoint.y >= bounds.min.y - textBoundsTolerance
                && localPoint.y <= bounds.max.y + textBoundsTolerance;
        }

        // ---------------------------------------------------------------
        // 查询工具
        // ---------------------------------------------------------------

        private bool HasPinnedPanelForOption(string description)
        {
            // 简单比较原始描述文本（未处理），避免二次处理比较问题
            foreach (var panel in _pinnedPanels)
            {
                if (panel != null && panel.DescriptionText != null &&
                    panel.DescriptionText.text.Contains(description.Substring(0, Mathf.Min(description.Length, 10))))
                {
                    return true;
                }
            }
            return false;
        }

        private void CloseHoverPanel()
        {
            if (_hoverPanel != null && _hoverPanel.gameObject != null)
                Destroy(_hoverPanel.gameObject);
            _hoverPanel = null;
        }

        private void CloseAllPinnedPanels()
        {
            foreach (var panel in _pinnedPanels)
            {
                if (panel != null && panel.gameObject != null)
                    Destroy(panel.gameObject);
            }
            _pinnedPanels.Clear();
        }
    }
}