using UnityEngine;
using UnityEngine.UI;
using TMPro;

[RequireComponent(typeof(RectTransform))]
public class HintWindowController : MonoBehaviour
{
    [SerializeField] private TextMeshProUGUI _text;
    [SerializeField] private Vector2 _padding = new Vector2(16, 10);
    [SerializeField] private Vector2 _anchorOffset = new Vector2(16, 16);

    private RectTransform  _selfRt;
    private Canvas         _rootCanvas;
    private Camera         _uiCamera;

    private void Awake()
    {
        _selfRt   = (RectTransform)transform;
        _rootCanvas = GetComponentInParent<Canvas>();
        _uiCamera   = _rootCanvas.worldCamera;

        // 兜底找 Text
        if (_text == null)
            _text = GetComponentInChildren<TextMeshProUGUI>(true);

        if (_text == null)
            Debug.LogError("[HintWindowController] 找不到 TextMeshProUGUI！", this);
    }

    public void Present(Vector2 mouseScreenPos)
    {
        if (_text == null) return;

        RefreshSize();
        ClampToScreen(mouseScreenPos);
    }

    public void RefreshSize()
    {
        _text.ForceMeshUpdate(false, false);
        LayoutRebuilder.ForceRebuildLayoutImmediate(_text.rectTransform);

        float w = _text.preferredWidth  + _padding.x * 2f;
        float h = _text.preferredHeight + _padding.y * 2f;

        _selfRt.SetSizeWithCurrentAnchors(RectTransform.Axis.Horizontal, w);
        _selfRt.SetSizeWithCurrentAnchors(RectTransform.Axis.Vertical,  h);

        Canvas.ForceUpdateCanvases();
    }

    private void ClampToScreen(Vector2 mouseScreenPos)
    {
        // 1. 获取 Canvas 的缩放因子，这是解决打包后问题的关键
        float scaleFactor = _rootCanvas.scaleFactor;
        if (scaleFactor <= 0) scaleFactor = 1f; // 极端情况下的保护
        // 2. 计算提示窗口在屏幕上的实际像素尺寸
        float windowW = _selfRt.rect.width  * scaleFactor;
        float windowH = _selfRt.rect.height * scaleFactor;
        // 3. 计算窗口左上角假想的屏幕坐标 (这里逻辑保持不变)
        Vector2 desiredTopLeft = mouseScreenPos + _anchorOffset;
        // 4. 修正：将假想的左上角位置限制在屏幕范围内
        //    使用 Screen.width 和 Screen.height 更直接
        float clampedX = Mathf.Clamp(desiredTopLeft.x, 0, Screen.width - windowW);
        float clampedY = Mathf.Clamp(desiredTopLeft.y, windowH, Screen.height); // Y坐标从下到上，所以下边界是windowH
        // 5. 关键修正：根据Pivot计算最终实际要设置的屏幕坐标点
        //    我们已经得到了窗口内容左上角的正确位置(clampedX, clampedY)。
        //    现在需要反推出在这种情况下，窗口的Pivot应该在屏幕的哪个坐标。
        Vector2 pivot = _selfRt.pivot;
        Vector2 pivotScreenPos = new Vector2(
            clampedX + pivot.x * windowW,
            clampedY - (1 - pivot.y) * windowH
        );
        // 6. 将计算出的Pivot屏幕坐标转换为Canvas的局部坐标
        RectTransform canvasRt = _rootCanvas.GetComponent<RectTransform>();
        RectTransformUtility.ScreenPointToLocalPointInRectangle(
            canvasRt,
            pivotScreenPos,
            _uiCamera,  // 即使_uiCamera为null (Overlay模式)，此方法依然有效
            out Vector2 localPos);
        // 7. 设置最终位置
        _selfRt.localPosition = localPos;
        _selfRt.SetAsLastSibling();
    }
}