using System;
using System.Collections;
using System.Collections.Generic;
using Fort23.UTool;
using UnityEngine;
using UnityEngine.EventSystems;

public class LongPressDragBtn : MonoBehaviour, IPointerDownHandler, IPointerUpHandler, IPointerExitHandler,
    IPointerClickHandler, IDragHandler, IBeginDragHandler, IEndDragHandler, IPointerEnterHandler
{
    private float _time;

    public float startTime = 0.5f;

    public float intervalTime = 0.05f;

    public Action onClick;

    /// <summary>
    /// 连按
    /// </summary>
    public Action longPress;

    /// <summary>
    /// 长按结束
    /// </summary>
    public Action longPressEnd;

    /// <summary>
    /// 是否按下状态
    /// </summary>
    [HideInInspector] public bool isPressd;

    private bool _isTriggerLongPress;

    /// <summary>
    /// 是否触发了长按
    /// </summary>
    public bool IsTriggerLongPress => _isTriggerLongPress;

    // 拖拽相关变量
    private bool _isDragging;
    private Vector2 _dragStartPosition;

    /// <summary>
    /// 拖拽阈值（像素），超过这个距离才认为是拖拽
    /// </summary>
    public float dragThreshold = 10f;

    /// <summary>
    /// 拖拽开始事件
    /// </summary>
    public Action<PointerEventData> onDragStart;

    /// <summary>
    /// 拖拽进行中事件
    /// </summary>
    public Action<PointerEventData> onDrag;

    /// <summary>
    /// 拖拽结束事件
    /// </summary>
    public Action<PointerEventData> onDragEnd;

    public Action<PointerEventData> onPointerEnter;

    public Action<PointerEventData> onPointerExit;

    void OnPress(bool pressed)
    {
        if (pressed) // 按下
        {
            isPressd = true;
            _isDragging = false; // 重置拖拽状态
        }
        else // 松开或离开
        {
            if (isPressd)
            {
                if (_isTriggerLongPress && !_isDragging) // 触发了长按且不是拖拽，执行 longPressEnd
                {
                    longPressEnd?.Invoke();
                    _isTriggerLongPress = false;
                }
            }

            isPressd = false;
            _time = 0;
        }
    }

    private void Update()
    {
        // 如果正在拖拽，不执行长按逻辑
        if (_isDragging) return;

        if (isPressd && !_isTriggerLongPress)
        {
            _time += Time.deltaTime;
            if (_time >= startTime)
            {
                _isTriggerLongPress = true;
                _time -= intervalTime;
                longPress?.Invoke();
            }
        }
        else if (isPressd && _isTriggerLongPress)
        {
            _time += Time.deltaTime;
            if (_time >= intervalTime)
            {
                _time -= intervalTime;
                longPress?.Invoke();
            }
        }
    }

    /// <summary>
    /// 终止
    /// </summary>
    public void Terminated()
    {
        if (isPressd)
        {
            isPressd = false;
            if (_isTriggerLongPress)
            {
                longPressEnd?.Invoke();
            }

            _isTriggerLongPress = false;
            _time = 0;
        }

        _isDragging = false; // 同时终止拖拽状态
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        _dragStartPosition = eventData.position;
        OnPress(true);
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        // 如果正在拖拽，先触发拖拽结束
        if (_isDragging)
        {
            OnEndDrag(eventData);
        }

        OnPress(false);
    }

    public void OnPointerExit(PointerEventData eventData)
    {
        onPointerExit?.Invoke(eventData);
        // 如果正在拖拽，不处理退出事件（拖拽过程中允许离开按钮区域）
        if (!_isDragging)
        {
            OnPress(false);
        }
    }

    public void OnPointerEnter(PointerEventData eventData)
    {
        onPointerEnter?.Invoke(eventData);
    }

    public void OnPointerClick(PointerEventData eventData)
    {
        // 如果发生了拖拽，不触发点击事件
        if (_isDragging || _isTriggerLongPress) return;

        onClick?.Invoke();
        isPressd = false;
    }

    // ========== 拖拽相关方法 ==========

    public void OnBeginDrag(PointerEventData eventData)
    {
        // 检查是否达到拖拽阈值
        if (Vector2.Distance(eventData.position, _dragStartPosition) >= dragThreshold && !_isDragging)
        {
            _isDragging = true;
            // 开始拖拽时终止长按逻辑
            if (_isTriggerLongPress)
            {
                longPressEnd?.Invoke();
                _isTriggerLongPress = false;
            }

            onDragStart?.Invoke(eventData);
        }
    }

    public void OnDrag(PointerEventData eventData)
    {
        if (_isDragging)
        {
            onDrag?.Invoke(eventData);
        }
        else
        {
            // 如果还没有正式开始拖拽，检查是否达到阈值
            if (Vector2.Distance(eventData.position, _dragStartPosition) >= dragThreshold)
            {
                OnBeginDrag(eventData);
            }
        }
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        if (_isDragging)
        {
            onDragEnd?.Invoke(eventData);
            _isDragging = false;
        }
    }

    /// <summary>
    /// 检查是否正在拖拽
    /// </summary>
    public bool IsDragging => _isDragging;

    /// <summary>
    /// 强制结束拖拽
    /// </summary>
    public void ForceEndDrag()
    {
        if (_isDragging)
        {
            _isDragging = false;
            onDragEnd?.Invoke(null);
        }
    }
}