using System;
using UnityEngine;
using UnityEngine.EventSystems;

// 为避免潜在的冲突和更清晰的逻辑，建议将类名稍作更改，以反映其新功能
// 例如：UIMouseBlocker，或者就保持 UIBlockCameraDrag 也可以，只要功能上能理解
public class UIBlockCameraDrag : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler, IPointerDownHandler, IPointerUpHandler
{
    public static bool IsPointerOnUI = false;
    public static bool ShouldBlockDrag = false;
    public static bool MoveEvent = false;
    public static bool DownUpEvent = false;
    public static Vector3 DragOrigin;
    public static Vector3 MoveVector;
    private static UIBlockCameraDrag _activeBlocker;

    private bool _isPointerInside;

    //是否ban点击
    public bool BanClick = false;

    public static void ResetState()
    {
        IsPointerOnUI = false;
        ShouldBlockDrag = false;
        MoveEvent = false;
        DownUpEvent = false;
        DragOrigin = Vector3.zero;
        MoveVector = Vector3.zero;
        _activeBlocker = null;
    }

    private static Vector3 GetMouseWorldPosition()
    {
        var mainCamera = Camera.main;
        return mainCamera == null ? Vector3.zero : mainCamera.ScreenToWorldPoint(Input.mousePosition);
    }

    private void ClearDragState()
    {
        if (_activeBlocker != null && _activeBlocker != this)
            return;

        if (_activeBlocker == this)
            _activeBlocker = null;

        ShouldBlockDrag = false;
        MoveEvent = false;
        DragOrigin = Vector3.zero;
        MoveVector = Vector3.zero;
    }
    
    public void OnPointerEnter(PointerEventData eventData)
    {
        _isPointerInside = true;
        IsPointerOnUI = true;
    }
    
    public void OnPointerExit(PointerEventData eventData)
    {
        _isPointerInside = false;
        IsPointerOnUI = false;
        ClearDragState();
    }
    
    public void OnPointerDown(PointerEventData eventData)
    {
        if (eventData.button == PointerEventData.InputButton.Left)
        {
            // OnPointerEnter may be missed after reconnect/reset if the cursor is already on this raycast target.
            _isPointerInside = true;
            IsPointerOnUI = true;
            _activeBlocker = this;
            ShouldBlockDrag = true;
            MoveEvent = false;
            DragOrigin = GetMouseWorldPosition();
            MoveVector = Vector3.zero;
        }
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        if (eventData.button == PointerEventData.InputButton.Left)
        {
            if ((_activeBlocker == this || _isPointerInside) && !MoveEvent && !BanClick)
                DownUpEvent = true;

            IsPointerOnUI = _isPointerInside;
            ClearDragState();
        }
    }

    private void OnDisable()
    {
        _isPointerInside = false;
        if (_activeBlocker == this)
            ResetState();
    }
    
    public void Update()
    {
        if (ShouldBlockDrag)
        {
            MoveVector = DragOrigin - GetMouseWorldPosition();
            if (MoveVector.magnitude > 0.01f)
            {
                MoveEvent = true;
            }
        }
    }
}