using System;
using Cielonos.MainGame.Map;
using TMPro;
using UnityEngine;
using UnityEngine.UI;

namespace Cielonos.MainGame.UI
{
    /// <summary>
    /// 地图上的单个节点 UI 元素。
    /// 由 MapUIPage 动态实例化，定位在 RunMapNode.position 对应的 UI 坐标上。
    /// 通过 ApplyDisplayState 控制可见性、交互性和边框颜色。
    /// </summary>
    public class MapNodeElement : MonoBehaviour
    {
        // ================================================================
        // 边框颜色常量
        // ================================================================

        /// <summary>Outline 偏移量，控制边框粗细。</summary>
        private static readonly Vector2 OUTLINE_DISTANCE = new Vector2(3f, 3f);

        /// <summary>已访问节点的边框颜色（白色）。</summary>
        private static readonly Color OUTLINE_COLOR_VISITED = Color.white;

        /// <summary>可前往但未访问节点的边框颜色（绿色）。</summary>
        private static readonly Color OUTLINE_COLOR_SELECTABLE = new Color(0.2f, 0.9f, 0.2f, 1f);

        /// <summary>不可前往节点的边框颜色（红色）。</summary>
        private static readonly Color OUTLINE_COLOR_LOCKED = new Color(0.9f, 0.2f, 0.2f, 1f);

        /// <summary>当前所在节点的边框颜色（金黄色）。</summary>
        private static readonly Color OUTLINE_COLOR_CURRENT = new Color(1f, 0.9f, 0.3f, 1f);

        // ================================================================
        // 序列化字段
        // ================================================================

        [Header("References")]
        [SerializeField] private Image iconImage;
        [SerializeField] private Image backgroundImage;
        [SerializeField] private TMP_Text labelText;
        [SerializeField] private Button button;

        // ================================================================
        // 公共属性
        // ================================================================

        /// <summary>关联的网格坐标。</summary>
        public Vector2Int GridPosition { get; private set; }

        /// <summary>关联的节点类型。</summary>
        public MapNodeType NodeType { get; private set; }

        /// <summary>当前显示状态。</summary>
        public NodeDisplayState DisplayState { get; private set; }

        /// <summary>节点被玩家点击时触发，参数为该节点的网格坐标。</summary>
        public event Action<Vector2Int> OnClicked;

        // ================================================================
        // 运行时字段
        // ================================================================

        /// <summary>运行时自动创建的 Outline 组件，用于显示交互状态边框。</summary>
        private Outline _outline;

        // ================================================================
        // 初始化
        // ================================================================

        /// <summary>
        /// 初始化节点元素，设置网格坐标、类型、UI 位置，并绑定点击事件。
        /// </summary>
        /// <param name="node">对应的 RunMapNode 数据。</param>
        public void Setup(RunMapNode node)
        {
            GridPosition = node.gridPosition;
            NodeType = node.nodeType;

            // 将节点定位到 UI 坐标
            RectTransform rt = GetComponent<RectTransform>();
            if (rt != null)
            {
                rt.anchoredPosition = node.position;
            }

            // 设置标签文本为节点类型简称
            if (labelText != null)
            {
                labelText.text = GetNodeLabel(node.nodeType);
            }

            // 设置背景颜色
            if (backgroundImage != null)
            {
                backgroundImage.color = GetNodeColor(node.nodeType);
            }

            // 确保 Outline 组件存在
            EnsureOutline();

            // 绑定按钮点击 → 触发 OnClicked 事件
            if (button != null)
            {
                button.onClick.AddListener(HandleClick);
            }
        }

        // ================================================================
        // 显示状态
        // ================================================================

        /// <summary>
        /// 更新节点的完整显示状态（可见性、交互性、使用状态、边框颜色）。
        /// 由 MapUIPage.RefreshDisplayStates 批量调用。
        /// </summary>
        public void ApplyDisplayState(NodeDisplayState state)
        {
            DisplayState = state;

            // --- 可见性 ---
            // 所有节点始终可见：Hidden 不再出现，但保留防御性处理
            switch (state.visibility)
            {
                case MapNodeVisibility.Hidden:
                case MapNodeVisibility.Silhouette:
                    gameObject.SetActive(true);
                    if (iconImage != null) iconImage.enabled = false;
                    if (labelText != null) labelText.text = "?";
                    if (backgroundImage != null)
                        backgroundImage.color = new Color(0.4f, 0.4f, 0.4f, 0.6f);
                    break;

                case MapNodeVisibility.Revealed:
                    gameObject.SetActive(true);
                    if (iconImage != null) iconImage.enabled = true;
                    if (labelText != null) labelText.text = GetNodeLabel(NodeType);
                    if (backgroundImage != null)
                        backgroundImage.color = GetNodeColor(NodeType);
                    break;
            }

            // --- 交互性（按钮是否可点击） ---
            if (button != null)
            {
                button.interactable = state.interaction == MapNodeInteraction.Selectable;
            }

            // --- 使用状态的视觉反馈（已访问/已用完的节点背景变暗） ---
            ApplyUsageVisual(state.usage, state.interaction);

            // --- 边框颜色（白/绿/红/金） ---
            ApplyOutlineVisual(state);
        }

        // ================================================================
        // Outline 边框
        // ================================================================

        /// <summary>
        /// 确保 backgroundImage 上存在 Outline 组件。
        /// 首次调用时自动添加。
        /// </summary>
        private void EnsureOutline()
        {
            if (_outline != null) return;
            if (backgroundImage == null) return;

            _outline = backgroundImage.GetComponent<Outline>();
            if (_outline == null)
            {
                _outline = backgroundImage.gameObject.AddComponent<Outline>();
            }

            _outline.effectDistance = OUTLINE_DISTANCE;
        }

        /// <summary>
        /// 根据节点的显示状态设置 Outline 边框颜色。
        /// 优先级从高到低：
        ///   1. 当前所在节点 → 金黄色
        ///   2. 已访问/已用完  → 白色
        ///   3. 可前往但未访问 → 绿色
        ///   4. 不可前往       → 红色
        /// Hidden 节点已被 SetActive(false)，不在此处理。
        /// </summary>
        private void ApplyOutlineVisual(NodeDisplayState state)
        {
            EnsureOutline();
            if (_outline == null) return;

            _outline.enabled = true;

            // 优先级 1：当前所在节点 → 金黄色边框
            if (state.interaction == MapNodeInteraction.Current)
            {
                _outline.effectColor = OUTLINE_COLOR_CURRENT;
                return;
            }

            // 优先级 2：已访问或已用完 → 白色边框
            if (state.usage == MapNodeUsage.Visited || state.usage == MapNodeUsage.Exhausted)
            {
                _outline.effectColor = OUTLINE_COLOR_VISITED;
                return;
            }

            // 优先级 3：可前往但未曾去过 → 绿色边框
            if (state.interaction == MapNodeInteraction.Selectable)
            {
                _outline.effectColor = OUTLINE_COLOR_SELECTABLE;
                return;
            }

            // 优先级 4：不可前往（Locked）→ 红色边框
            _outline.effectColor = OUTLINE_COLOR_LOCKED;
        }

        // ================================================================
        // 使用状态视觉
        // ================================================================

        /// <summary>
        /// 根据使用状态调整视觉效果（已访问/已用完的节点背景变暗）。
        /// </summary>
        private void ApplyUsageVisual(MapNodeUsage usage, MapNodeInteraction interaction)
        {
            if (backgroundImage == null) return;

            Color baseColor = backgroundImage.color;

            switch (usage)
            {
                case MapNodeUsage.Visited:
                    // 已访问节点稍微变暗
                    backgroundImage.color = new Color(baseColor.r * 0.7f, baseColor.g * 0.7f,
                        baseColor.b * 0.7f, baseColor.a);
                    break;

                case MapNodeUsage.Exhausted:
                    // 已用完的节点明显变暗
                    backgroundImage.color = new Color(baseColor.r * 0.4f, baseColor.g * 0.4f,
                        baseColor.b * 0.4f, baseColor.a * 0.6f);
                    break;
            }

            // 当前所在节点高亮（覆盖变暗效果）
            if (interaction == MapNodeInteraction.Current)
            {
                backgroundImage.color = Color.white;
            }
        }

        // ================================================================
        // 点击处理
        // ================================================================

        /// <summary>按钮点击回调，转发为 OnClicked 事件。</summary>
        private void HandleClick()
        {
            OnClicked?.Invoke(GridPosition);
        }

        // ================================================================
        // 静态工具方法
        // ================================================================

        /// <summary>获取节点类型的简称标签。</summary>
        private static string GetNodeLabel(MapNodeType type)
        {
            return type switch
            {
                MapNodeType.Start => "S",
                MapNodeType.NormalBattle => "B",
                MapNodeType.EliteBattle => "E",
                MapNodeType.BossBattle => "BOSS",
                MapNodeType.MechanicalTable => "T",
                MapNodeType.LogisticsCenter => "$",
                MapNodeType.MedicalStation => "+",
                _ => "?"
            };
        }

        /// <summary>获取节点类型对应的背景颜色。</summary>
        private static Color GetNodeColor(MapNodeType type)
        {
            return type switch
            {
                MapNodeType.Start => new Color(0.2f, 0.8f, 0.2f, 1f),          // 绿色
                MapNodeType.NormalBattle => new Color(0.6f, 0.6f, 0.6f, 1f),    // 灰色
                MapNodeType.EliteBattle => new Color(0.9f, 0.6f, 0.1f, 1f),     // 橙色
                MapNodeType.BossBattle => new Color(0.9f, 0.1f, 0.1f, 1f),      // 红色
                MapNodeType.MechanicalTable => new Color(0.3f, 0.5f, 0.9f, 1f), // 蓝色
                MapNodeType.LogisticsCenter => new Color(0.9f, 0.85f, 0.2f, 1f),// 金色
                MapNodeType.MedicalStation => new Color(0.3f, 0.9f, 0.6f, 1f),  // 青绿
                _ => Color.white
            };
        }
    }
}