using System.Collections;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
using XRLib.UI;

namespace XED.UI
{
    public class Panel_DragHandler : PanelBase
    {
        Image selectionBoxImage;
        Vector2 startPosition;
        Rect selectionRect;
        public event System.Action<Rect> onDragBoxSelect;
        private void Awake()
        {
            foreach (Image img in GetComponentsInChildren<Image>(true))
            {
                if (img.transform != transform)
                {
                    selectionBoxImage = img; 
                    break;
                }
            }
        }
        public void OnBeginDrag(PointerEventData eventData)
        {
            selectionBoxImage.gameObject.SetActive(true);
            startPosition = eventData.position;
            selectionRect = new Rect();
        }
        public void OnBeginDrag(Vector3 position)
        {
            selectionBoxImage.gameObject.SetActive(true);
            startPosition = position;
            selectionRect = new Rect();
            StopAllCoroutines();
            StartCoroutine(CoroutineOnDrag());
        }

        public void OnDrag(PointerEventData eventData)
        {
            SetSelectionBoxSize(eventData.position);
        }

        public void OnEndDrag(PointerEventData eventData)
        {
            selectionBoxImage.gameObject.SetActive(false);
            onDragBoxSelect?.Invoke(selectionRect);
        }
        public void OnEndDrag(Vector3 position)
        {
            if (!selectionBoxImage.gameObject.activeSelf) return;
            selectionBoxImage.gameObject.SetActive(false);
            StopAllCoroutines();
            SetSelectionBoxSize(position);
            onDragBoxSelect?.Invoke(selectionRect);
        }
        public void ForceEndDrag()
        {
            selectionBoxImage.gameObject.SetActive(false);
            StopAllCoroutines();
        }
        public void SetSelectionBoxSize(Vector3 position)
        {
            if (position.x < startPosition.x)
            {
                selectionRect.xMin = position.x;
                selectionRect.xMax = startPosition.x;
            }
            else
            {
                selectionRect.xMin = startPosition.x;
                selectionRect.xMax = position.x;
            }
            if (position.y < startPosition.y)
            {
                selectionRect.yMin = position.y;
                selectionRect.yMax = startPosition.y;
            }
            else
            {
                selectionRect.yMin = startPosition.y;
                selectionRect.yMax = position.y;
            }
            selectionBoxImage.rectTransform.offsetMin = selectionRect.min;
            selectionBoxImage.rectTransform.offsetMax = selectionRect.max;
        }
        IEnumerator CoroutineOnDrag()
        {
            while (true)
            {
                SetSelectionBoxSize(Input.mousePosition);
                yield return null;
            }
        }
    }
}