using System;
using UnityEngine;
using UnityEngine.EventSystems;

namespace Studio
{
    public class MouseObserver : MonoBehaviour
    {
        public Action onMouseExitClick;

        public bool isPointerOverSelf;

        private RectTransform rectTransform;
        private bool prevPointerOverSelf = false;

        private void Awake()
        {
            rectTransform = GetComponent<RectTransform>();
        }

        private void Update()
        {
            if (rectTransform == null)
                return;

            // ¸¶¿ì½º°¡ ÀÚ½ÅÀÇ UI(RectTransform) ¿µ¿ª À§¿¡ ÀÖ´ÂÁö ÆǺ°
            bool isOver = RectTransformUtility.RectangleContainsScreenPoint(
                rectTransform,
                Input.mousePosition,
                GetEventCamera()
            );

            if (isOver && !prevPointerOverSelf)
            {
                isPointerOverSelf = true;
            }
            else if (!isOver && prevPointerOverSelf)
            {
                isPointerOverSelf = false;
            }

            prevPointerOverSelf = isOver;

            if (Input.GetMouseButtonDown(0) && !isPointerOverSelf)
            {
                onMouseExitClick?.Invoke();
            }
        }

        // UI¿ë Ä«¸Þ¶ó ¹Ýȯ (¾øÀ¸¸é null)
        private Camera GetEventCamera()
        {
            if (EventSystem.current != null && EventSystem.current.currentInputModule is StandaloneInputModule sim)
            {
                return sim.inputOverride?.mousePresent == true ? Camera.main : null;
            }
            return Camera.main;
        }
    }
}