using System.Collections;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;

namespace GameFramework
{
    /// <summary>
    /// 游戏失败叠加层 —— 直接挂在 Gameplay 场景的 Canvas 上。
    /// 
    /// 使用方式：
    ///   1. 在 Gameplay 场景里创建一个空物体，挂上本脚本
    ///   2. 运行一次游戏（或点 Editor 按钮），脚本会自动构建子 UI
    ///   3. 停止运行后，子 UI 留在场景中，可自由编辑样式/位置/精灵
    ///   4. 运行时由 GameManager 调用 GameLostOverlay.Show() 激活
    /// 
    /// 所有 UI 元素均为 [SerializeField]，可在 Inspector 中替换。
    /// </summary>
    public class GameLostOverlay : MonoBehaviour
    {
        private static GameLostOverlay _instance;

        // ====== Canvas ======
        [Header("Canvas（留空则自动创建）")]
        [SerializeField] private Canvas lostCanvas;

        // ====== UI 元素引用（全部可编辑） ======
        [Header("背景蒙版")]
        [SerializeField] private Image dimBackground;

        [Header("标题 —— 你已迷失……")]
        [SerializeField] private Text lostTitleText;
        [SerializeField] private Image lostTitleImage;    // 可用图片替代文字

        [Header("装饰")]
        [SerializeField] private Image leftDecoration;
        [SerializeField] private Image rightDecoration;

        [Header("主界面按钮")]
        [SerializeField] private Button mainMenuButton;
        [SerializeField] private Image mainMenuButtonImage;

        [Header("音效")]
        [SerializeField] private AudioData lostSFX;

        [Header("标题渐现动效")]
        [Tooltip("标题渐现总时长（秒）")]
        [SerializeField] private float titleFadeDuration = 1.5f;
        [Tooltip("水面波纹位置抖动幅度（像素）")]
        [SerializeField] private float ripplePositionAmplitude = 8f;
        [Tooltip("水面波纹缩放抖动幅度")]
        [SerializeField] private float rippleScaleAmplitude = 0.08f;
        [Tooltip("水面波纹频率（越大抖动越快）")]
        [SerializeField] private float rippleFrequency = 15f;
        [Tooltip("水波纹材质（留空则自动从 Shader 创建）")]
        [SerializeField] private Material rippleMaterial;
        [Tooltip("主界面按钮延迟出现时间（秒）")]
        [SerializeField] private float buttonFadeDelay = 2f;
        [Tooltip("按钮渐现时长（秒）")]
        [SerializeField] private float buttonFadeDuration = 0.5f;

        private bool _isVisible;
        private Coroutine _titleAnimCoroutine;
        private Coroutine _buttonFadeCoroutine;
        private Material _rippleMaterial;

        // ====================================================================
        //  静态入口
        // ====================================================================

        /// <summary>
        /// 显示失败叠加层。优先使用场景中已有的实例，
        /// 没有则动态创建一个。
        /// </summary>
        public static void Show()
        {
            // 场景中已有（隐藏的）实例？
            if (_instance != null)
            {
                _instance.Activate();
                return;
            }

            // 尝试在场景中找到
            var found = FindObjectOfType<GameLostOverlay>();
            if (found != null)
            {
                _instance = found;
                found.Activate();
                return;
            }

            // 都没有 → 动态创建
            var obj = new GameObject("GameLostOverlay");
            var overlay = obj.AddComponent<GameLostOverlay>();
            overlay.BuildAll();
            overlay.Activate();
        }

        // ====================================================================
        //  生命周期
        // ====================================================================

        void Awake()
        {
            _instance = this;

            // 如果 Canvas 还没赋值，尝试从自身获取
            if (lostCanvas == null)
                lostCanvas = GetComponent<Canvas>();

            // 初始隐藏
            if (lostCanvas != null)
                lostCanvas.enabled = false;
        }

        void Update()
        {
            if (!_isVisible) return;

            if (Input.GetKeyDown(KeyCode.Return) || Input.GetKeyDown(KeyCode.Space) || Input.GetKeyDown(KeyCode.Escape))
            {
                ReturnToMainMenu();
            }
        }

        // ====================================================================
        //  激活 / 隐藏
        // ====================================================================

        private void Activate()
        {
            _isVisible = true;

            if (lostCanvas != null)
                lostCanvas.enabled = true;

            // 自动查找标题元素（兜底：Inspector 未赋值时从 Canvas 子节点中找）
            AutoFindTitleElement();

            Debug.Log($"[GameLostOverlay] Activate - lostTitleImage={lostTitleImage != null}, lostTitleText={lostTitleText != null}, canvas={lostCanvas != null}");

            // 启动标题渐现动效（水面波纹 + 渐现）
            if (_titleAnimCoroutine != null)
                StopCoroutine(_titleAnimCoroutine);
            _titleAnimCoroutine = StartCoroutine(TitleRippleFadeIn());

            // 绑定按钮 + 延迟渐现
            if (mainMenuButton != null)
            {
                mainMenuButton.onClick.RemoveAllListeners();
                mainMenuButton.onClick.AddListener(ReturnToMainMenu);

                // 初始隐藏按钮
                SetButtonAlpha(0f);

                // 延迟后渐现
                if (_buttonFadeCoroutine != null)
                    StopCoroutine(_buttonFadeCoroutine);
                _buttonFadeCoroutine = StartCoroutine(ButtonFadeIn());
            }

            // 音效
            if (AudioManager.Instance != null && lostSFX != null)
                AudioManager.Instance.PlaySFX(lostSFX);

            // 显示鼠标
            Cursor.visible = true;
            Cursor.lockState = CursorLockMode.None;

            // 确保 EventSystem 有输入模块（UI 点击必需）
            EnsureEventSystemInputModule();
        }

        /// <summary>
        /// 确保 EventSystem 有 StandaloneInputModule，否则 UI 按钮无法响应点击。
        /// </summary>
        private void EnsureEventSystemInputModule()
        {
            var es = UnityEngine.EventSystems.EventSystem.current;
            if (es == null) return;
            if (es.GetComponent<UnityEngine.EventSystems.StandaloneInputModule>() == null)
            {
                es.gameObject.AddComponent<UnityEngine.EventSystems.StandaloneInputModule>();
                Debug.Log("[GameLostOverlay] 已自动添加 StandaloneInputModule");
            }
        }

        /// <summary>
        /// 按钮延迟渐现协程：等待 buttonFadeDelay 秒后，用 buttonFadeDuration 秒渐现。
        /// </summary>
        private IEnumerator ButtonFadeIn()
        {
            yield return new WaitForSecondsRealtime(buttonFadeDelay);

            float elapsed = 0f;
            while (elapsed < buttonFadeDuration)
            {
                elapsed += Time.unscaledDeltaTime;
                float t = Mathf.Clamp01(elapsed / buttonFadeDuration);
                SetButtonAlpha(t);
                yield return null;
            }
            SetButtonAlpha(1f);

            if (mainMenuButton != null)
                mainMenuButton.Select();
        }

        /// <summary>
        /// 设置按钮整体透明度（通过 Image.color.a）。
        /// </summary>
        private void SetButtonAlpha(float alpha)
        {
            if (mainMenuButtonImage != null)
            {
                var c = mainMenuButtonImage.color;
                c.a = alpha;
                mainMenuButtonImage.color = c;
            }
            // 同时处理按钮子物体的 Text
            if (mainMenuButton != null)
            {
                var texts = mainMenuButton.GetComponentsInChildren<Text>(true);
                foreach (var t in texts)
                {
                    var c = t.color;
                    c.a = alpha;
                    t.color = c;
                }
            }
        }

        /// <summary>
        /// 返回主界面。
        /// </summary>
        private void ReturnToMainMenu()
        {
            _isVisible = false;

            Time.timeScale = 1f;
            Cursor.visible = true;
            Cursor.lockState = CursorLockMode.None;

            if (SceneLoader.Instance != null)
                SceneLoader.Instance.LoadMainMenuScene();
            else
                SceneManager.LoadScene("MainMenu");
        }

        /// <summary>
        /// 自动查找标题元素。搜索范围：
        /// 1. 自身 transform 子节点
        /// 2. 场景中所有 Canvas 的子节点
        /// 3. 都找不到则动态创建
        /// </summary>
        private void AutoFindTitleElement()
        {
            if (lostTitleImage != null || lostTitleText != null) return;

            // 1. 从自身子节点查找
            TryFindTitleInHierarchy(transform);
            if (lostTitleText != null || lostTitleImage != null) return;

            // 2. 从 lostCanvas 子节点查找
            if (lostCanvas != null)
            {
                TryFindTitleInHierarchy(lostCanvas.transform);
                if (lostTitleText != null || lostTitleImage != null) return;
            }

            // 3. 从场景中所有 Canvas 查找
            var allCanvases = FindObjectsOfType<Canvas>();
            foreach (var c in allCanvases)
            {
                if (c == lostCanvas) continue;
                TryFindTitleInHierarchy(c.transform);
                if (lostTitleText != null || lostTitleImage != null) return;
            }

            // 4. 都找不到
            Debug.LogWarning("[GameLostOverlay] 未找到标题元素，请在 Inspector 中拖入 lostTitleImage 或 lostTitleText。");
        }

        private void TryFindTitleInHierarchy(Transform root)
        {
            // 按路径查找
            var titleObj = root.Find("CenterPanel/LostTitle");
            if (titleObj != null)
            {
                lostTitleImage = titleObj.GetComponent<Image>();
                if (lostTitleImage != null) return;
                lostTitleText = titleObj.GetComponent<Text>();
                if (lostTitleText != null) return;
            }

            // 按名称查找 Image（lostTitleImage 节点）
            var allImages = root.GetComponentsInChildren<Image>(true);
            foreach (var img in allImages)
            {
                var name = img.gameObject.name.ToLower();
                if (name.Contains("lost") || name.Contains("title") || name.Contains("迷失"))
                {
                    lostTitleImage = img;
                    return;
                }
            }

            // 按文字内容查找 Text
            var allTexts = root.GetComponentsInChildren<Text>(true);
            foreach (var t in allTexts)
            {
                if (t.text.Contains("迷失") || t.text.Contains("Lost"))
                {
                    lostTitleText = t;
                    return;
                }
            }

            // 兜底：第一个非按钮 Text
            foreach (var t in allTexts)
            {
                if (t.GetComponentInParent<Button>() == null)
                {
                    lostTitleText = t;
                    return;
                }
            }
        }

        /// <summary>
        /// 标题渐现动效：Shader 水波纹扭曲 + 透明度渐现。
        /// 前 60% 时间波纹强烈，后 40% 时间波纹减弱至消失。
        /// 使用 unscaledDeltaTime 不受 timeScale 暂停影响。
        /// </summary>
        private IEnumerator TitleRippleFadeIn()
        {
            float elapsed = 0f;

            // 优先用图片（Shader 动效），其次用文字（抖动动效）
            Image titleImg = lostTitleImage;
            Text titleTxt = lostTitleText;

            // ---- Image: Shader 水波纹 ----
            if (titleImg != null)
            {
                // 创建/获取水波纹材质
                if (_rippleMaterial == null)
                {
                    // 优先用 Inspector 拖入的材质
                    if (rippleMaterial != null)
                    {
                        _rippleMaterial = rippleMaterial;
                        Debug.Log("[GameLostOverlay] 使用 Inspector 指定的水波纹材质。");
                    }
                    else
                    {
                        var shader = Shader.Find("GameFramework/UI/WaterRippleFade");
                        if (shader == null)
                        {
                            Debug.LogWarning("[GameLostOverlay] 找不到 WaterRippleFade Shader！请确认 Assets/UI/shaders/WaterRippleFade.shader 存在且无编译错误。回退到抖动动效。");
                        }
                        else
                        {
                            _rippleMaterial = new Material(shader);
                            _rippleMaterial.SetFloat("_RippleAmplitude", ripplePositionAmplitude / 100f);
                            _rippleMaterial.SetFloat("_RippleFrequency", rippleFrequency);
                            _rippleMaterial.SetFloat("_RippleSpeed", 3f);
                            Debug.Log($"[GameLostOverlay] 已创建水波纹材质 - Amp={ripplePositionAmplitude / 100f}, Freq={rippleFrequency}");
                        }
                    }
                }

                if (_rippleMaterial != null)
                {
                    titleImg.material = _rippleMaterial;
                    _rippleMaterial.SetFloat("_RippleIntensity", 1f);
                    _rippleMaterial.SetFloat("_FadeAlpha", 0f);
                }

                while (elapsed < titleFadeDuration)
                {
                    elapsed += Time.unscaledDeltaTime;
                    float t = Mathf.Clamp01(elapsed / titleFadeDuration);

                    // 波纹强度：前 60% 强，后 40% 衰减至 0
                    float rippleIntensity;
                    if (t < 0.6f)
                        rippleIntensity = 1f;
                    else
                        rippleIntensity = Mathf.InverseLerp(1f, 0.6f, t);

                    // 渐现曲线（EaseOut）
                    float fadeT = 1f - Mathf.Pow(1f - t, 2.5f);

                    if (_rippleMaterial != null)
                    {
                        _rippleMaterial.SetFloat("_RippleIntensity", rippleIntensity);
                        _rippleMaterial.SetFloat("_FadeAlpha", fadeT);
                    }

                    yield return null;
                }

                // 确保最终状态
                if (_rippleMaterial != null)
                {
                    _rippleMaterial.SetFloat("_RippleIntensity", 0f);
                    _rippleMaterial.SetFloat("_FadeAlpha", 1f);
                }
                yield break;
            }

            // ---- Text: 抖动动效（回退方案） ----
            if (titleTxt != null)
            {
                var titleTransform = titleTxt.rectTransform;
                var c = titleTxt.color;
                c.a = 0f;
                titleTxt.color = c;
                Vector2 targetPosition = titleTransform.anchoredPosition;
                Vector3 targetScale = titleTransform.localScale;

                while (elapsed < titleFadeDuration)
                {
                    elapsed += Time.unscaledDeltaTime;
                    float t = Mathf.Clamp01(elapsed / titleFadeDuration);

                    float rippleIntensity = t < 0.6f ? 1f : Mathf.InverseLerp(1f, 0.6f, t);
                    float fadeT = 1f - Mathf.Pow(1f - t, 2.5f);

                    float jitterX = Random.Range(-1f, 1f) * ripplePositionAmplitude * rippleIntensity;
                    float jitterY = Random.Range(-1f, 1f) * ripplePositionAmplitude * rippleIntensity * 0.5f;
                    float jitterScale = Random.Range(-1f, 1f) * rippleScaleAmplitude * rippleIntensity;

                    titleTransform.anchoredPosition = targetPosition + new Vector2(jitterX, jitterY);
                    titleTransform.localScale = targetScale * (1f + jitterScale);

                    var col = titleTxt.color;
                    col.a = fadeT;
                    titleTxt.color = col;

                    yield return null;
                }

                titleTransform.anchoredPosition = targetPosition;
                titleTransform.localScale = targetScale;
                var finalCol = titleTxt.color;
                finalCol.a = 1f;
                titleTxt.color = finalCol;
            }
        }

        // ====================================================================
        //  Editor 辅助：一键构建 UI 子节点（在场景编辑时调用）
        // ====================================================================

#if UNITY_EDITOR
        /// <summary>
        /// 在 Unity 编辑器中调用此方法，自动构建所有 UI 子节点。
        /// 构建完成后停止运行，即可在 Inspector 中编辑所有引用。
        /// </summary>
        [ContextMenu("构建 UI（Build UI）")]
        public void EditorBuildUI()
        {
            BuildAll();
            // 构建完显示 Canvas 方便预览
            if (lostCanvas != null)
                lostCanvas.enabled = true;
            Debug.Log("[GameLostOverlay] UI 构建完成，可在场景中编辑。");
        }
#endif

        // ====================================================================
        //  动态构建 UI（首次使用 / 无预制体时）
        // ====================================================================

        /// <summary>
        /// 构建整个 UI 结构。构建后所有引用自动填入 SerializeField。
        /// </summary>
        private void BuildAll()
        {
            // ---- Canvas ----
            if (lostCanvas == null)
            {
                var canvasObj = new GameObject("LostCanvas");
                canvasObj.transform.SetParent(transform, false);

                lostCanvas = canvasObj.AddComponent<Canvas>();
                lostCanvas.renderMode = RenderMode.ScreenSpaceOverlay;
                lostCanvas.sortingOrder = 100000;

                var scaler = canvasObj.AddComponent<CanvasScaler>();
                scaler.uiScaleMode = CanvasScaler.ScaleMode.ScaleWithScreenSize;
                scaler.referenceResolution = new Vector2(1920, 1080);
                scaler.matchWidthOrHeight = 0.5f;

                canvasObj.AddComponent<GraphicRaycaster>();
            }

            var root = lostCanvas.gameObject;

            // ---- 全屏暗色蒙版 ----
            if (dimBackground == null)
                dimBackground = CreateFullScreenImage(root, "DimBackground", new Color(0f, 0f, 0f, 0.6f));

            // ---- 中央面板 ----
            var centerPanel = FindOrCreateChild(root, "CenterPanel");
            var cpRect = centerPanel.GetComponent<RectTransform>();
            if (cpRect.anchorMin == Vector2.zero && cpRect.anchorMax == Vector2.zero)
            {
                cpRect.anchorMin = new Vector2(0.15f, 0.3f);
                cpRect.anchorMax = new Vector2(0.85f, 0.75f);
                cpRect.sizeDelta = Vector2.zero;
            }

            // ---- 左装饰 ----
            if (leftDecoration == null)
                leftDecoration = CreateDecoration(centerPanel, "LeftDecoration", true);

            // ---- 右装饰 ----
            if (rightDecoration == null)
                rightDecoration = CreateDecoration(centerPanel, "RightDecoration", false);

            // ---- 标题文字 ----
            if (lostTitleText == null && lostTitleImage == null)
            {
                lostTitleText = CreateTitleText(centerPanel);
            }

            // ---- 主界面按钮 ----
            if (mainMenuButton == null)
                CreateMainMenuButton(centerPanel);
        }

        // ------ 构建子元素 ------

        private Image CreateFullScreenImage(GameObject parent, string name, Color color)
        {
            var obj = new GameObject(name);
            obj.transform.SetParent(parent.transform, false);
            var rect = obj.AddComponent<RectTransform>();
            rect.anchorMin = Vector2.zero;
            rect.anchorMax = Vector2.one;
            rect.sizeDelta = Vector2.zero;
            var img = obj.AddComponent<Image>();
            img.color = color;
            return img;
        }

        private GameObject FindOrCreateChild(GameObject parent, string name)
        {
            var t = parent.transform.Find(name);
            if (t != null) return t.gameObject;

            var obj = new GameObject(name);
            obj.transform.SetParent(parent.transform, false);
            obj.AddComponent<RectTransform>();
            return obj;
        }

        private Image CreateDecoration(GameObject parent, string name, bool isLeft)
        {
            var obj = new GameObject(name);
            obj.transform.SetParent(parent.transform, false);
            var rect = obj.AddComponent<RectTransform>();
            rect.anchorMin = new Vector2(0.5f, 0.5f);
            rect.anchorMax = new Vector2(0.5f, 0.5f);
            rect.pivot = new Vector2(0.5f, 0.5f);
            rect.sizeDelta = new Vector2(120, 200);
            rect.anchoredPosition = new Vector2(isLeft ? -300 : 300, 0);
            var img = obj.AddComponent<Image>();
            img.color = new Color(0.9f, 0.4f, 0.5f, 0.5f);
            return img;
        }

        private Text CreateTitleText(GameObject parent)
        {
            var obj = new GameObject("LostTitle");
            obj.transform.SetParent(parent.transform, false);
            var rect = obj.AddComponent<RectTransform>();
            rect.anchorMin = new Vector2(0.5f, 0.5f);
            rect.anchorMax = new Vector2(0.5f, 0.5f);
            rect.pivot = new Vector2(0.5f, 0.5f);
            rect.anchoredPosition = new Vector2(0, 30);
            rect.sizeDelta = new Vector2(800, 120);

            var text = obj.AddComponent<Text>();
            text.text = "你已迷失……";
            text.fontSize = 72;
            text.alignment = TextAnchor.MiddleCenter;
            text.color = Color.white;
            text.font = Resources.GetBuiltinResource<Font>("LegacyRuntime.ttf");
            text.fontStyle = FontStyle.Bold;

            var shadow = obj.AddComponent<Shadow>();
            shadow.effectColor = new Color(0f, 0f, 0f, 0.5f);
            shadow.effectDistance = new Vector2(3, -3);

            var outline = obj.AddComponent<Outline>();
            outline.effectColor = new Color(0.3f, 0.1f, 0.1f, 0.6f);
            outline.effectDistance = new Vector2(2, -2);

            return text;
        }

        private void CreateMainMenuButton(GameObject parent)
        {
            var btnObj = new GameObject("MainMenuButton");
            btnObj.transform.SetParent(parent.transform, false);

            var btnRect = btnObj.AddComponent<RectTransform>();
            btnRect.anchorMin = new Vector2(0.5f, 0.5f);
            btnRect.anchorMax = new Vector2(0.5f, 0.5f);
            btnRect.pivot = new Vector2(0.5f, 0.5f);
            btnRect.anchoredPosition = new Vector2(0, -80);
            btnRect.sizeDelta = new Vector2(200, 60);

            var btnImage = btnObj.AddComponent<Image>();
            btnImage.color = new Color(1f, 1f, 1f, 0.2f);

            mainMenuButtonImage = btnImage;

            var textObj = new GameObject("Text");
            textObj.transform.SetParent(btnObj.transform, false);
            var textRect = textObj.AddComponent<RectTransform>();
            textRect.anchorMin = Vector2.zero;
            textRect.anchorMax = Vector2.one;
            textRect.sizeDelta = Vector2.zero;

            var text = textObj.AddComponent<Text>();
            text.text = "主界面";
            text.fontSize = 28;
            text.alignment = TextAnchor.MiddleCenter;
            text.color = Color.white;
            text.font = Resources.GetBuiltinResource<Font>("LegacyRuntime.ttf");

            mainMenuButton = btnObj.AddComponent<Button>();
            var colors = mainMenuButton.colors;
            colors.highlightedColor = new Color(1.2f, 1.2f, 1.2f);
            colors.pressedColor = new Color(0.8f, 0.8f, 0.8f);
            mainMenuButton.colors = colors;
        }
    }
}