using UnityEngine;
using UnityEngine.EventSystems;

namespace UIWidgets
{
	public class DraggableHandle : MonoBehaviour, IDragHandler, IInitializePotentialDragHandler, IEventSystemHandler
	{
		private RectTransform drag;

		private Canvas canvas;

		private RectTransform canvasRect;

		public void Drag(RectTransform newDrag)
		{
			drag = newDrag;
		}

		public virtual void OnInitializePotentialDrag(PointerEventData eventData)
		{
			canvasRect = Utilites.FindCanvas(base.transform) as RectTransform;
			canvas = canvasRect.GetComponent<Canvas>();
		}

		public virtual void OnDrag(PointerEventData eventData)
		{
			if (canvas == null)
			{
				throw new MissingComponentException(base.gameObject.name + " not in Canvas hierarchy.");
			}
			Vector2 localPoint;
			RectTransformUtility.ScreenPointToLocalPointInRectangle(drag, eventData.position, eventData.pressEventCamera, out localPoint);
			Vector2 localPoint2;
			RectTransformUtility.ScreenPointToLocalPointInRectangle(drag, eventData.position - eventData.delta, eventData.pressEventCamera, out localPoint2);
			Vector3 localPosition = new Vector3(drag.localPosition.x + (localPoint.x - localPoint2.x), drag.localPosition.y + (localPoint.y - localPoint2.y), drag.localPosition.z);
			drag.localPosition = localPosition;
		}
	}
}