using System;
using UnityEngine;
using UnityEngine.EventSystems;

namespace LapinerTools.uMyGUI
{
	public class uMyGUI_Draggable : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler, IEventSystemHandler
	{
		public class DragEvent : EventArgs
		{
			public readonly PointerEventData m_event;

			public DragEvent(PointerEventData p_event)
			{
				m_event = p_event;
			}
		}

		[SerializeField]
		private bool m_isResetRotationWhenDragged;

		[SerializeField]
		private bool m_isSnapBackOnEndDrag;

		[SerializeField]
		private bool m_isTopInHierarchyWhenDragged = true;

		[SerializeField]
		private CanvasGroup m_disableBlocksRaycastsOnDrag;

		private bool m_isDragged;

		public EventHandler<DragEvent> m_onBeginDrag;

		public EventHandler<DragEvent> m_onDrag;

		public EventHandler<DragEvent> m_onEndDrag;

		private RectTransform m_initialParentTransform;

		private RectTransform m_canvasTransform;

		private RectTransform m_transform;

		private int m_initialSiblingIndex;

		private Vector3 m_initialPosition;

		private Quaternion m_initialRotation;

		private Vector3 m_dragOffset = Vector3.zero;

		public bool IsResetRotationWhenDragged
		{
			get
			{
				return m_isResetRotationWhenDragged;
			}
			set
			{
				m_isResetRotationWhenDragged = value;
			}
		}

		public bool IsSnapBackOnEndDrag
		{
			get
			{
				return m_isSnapBackOnEndDrag;
			}
			set
			{
				m_isSnapBackOnEndDrag = value;
			}
		}

		public bool IsTopInHierarchyWhenDragged
		{
			get
			{
				return m_isTopInHierarchyWhenDragged;
			}
			set
			{
				m_isTopInHierarchyWhenDragged = value;
			}
		}

		public CanvasGroup DisableBlocksRaycastsOnDrag
		{
			get
			{
				return m_disableBlocksRaycastsOnDrag;
			}
			set
			{
				m_disableBlocksRaycastsOnDrag = value;
			}
		}

		public bool IsDragged
		{
			get
			{
				return m_isDragged;
			}
		}

		public void OnBeginDrag(PointerEventData p_event)
		{
			m_isDragged = true;
			m_initialParentTransform = m_transform.parent as RectTransform;
			m_initialPosition = m_transform.position;
			m_initialRotation = m_transform.rotation;
			Vector3 worldPoint;
			if (RectTransformUtility.ScreenPointToWorldPointInRectangle(m_canvasTransform, p_event.position, p_event.pressEventCamera, out worldPoint))
			{
				m_dragOffset = m_transform.position - worldPoint;
			}
			else
			{
				m_dragOffset = Vector3.zero;
			}
			if (m_isResetRotationWhenDragged)
			{
				m_transform.rotation = Quaternion.identity;
			}
			if (m_isTopInHierarchyWhenDragged)
			{
				m_initialSiblingIndex = m_transform.GetSiblingIndex();
				m_transform.SetParent(m_canvasTransform, true);
				m_transform.SetAsLastSibling();
			}
			if (m_disableBlocksRaycastsOnDrag != null)
			{
				m_disableBlocksRaycastsOnDrag.blocksRaycasts = false;
			}
			if (m_onBeginDrag != null)
			{
				m_onBeginDrag(this, new DragEvent(p_event));
			}
		}

		public void OnDrag(PointerEventData p_event)
		{
			Vector3 worldPoint;
			if (RectTransformUtility.ScreenPointToWorldPointInRectangle(m_canvasTransform, p_event.position, p_event.pressEventCamera, out worldPoint))
			{
				m_transform.position = worldPoint + m_dragOffset;
			}
			if (m_onDrag != null)
			{
				m_onDrag(this, new DragEvent(p_event));
			}
		}

		public void OnEndDrag(PointerEventData p_event)
		{
			if (m_isDragged)
			{
				m_isDragged = false;
				if (m_isSnapBackOnEndDrag)
				{
					m_transform.position = m_initialPosition;
					m_transform.rotation = m_initialRotation;
				}
				if (m_isTopInHierarchyWhenDragged)
				{
					m_transform.SetParent(m_initialParentTransform, true);
					m_transform.SetSiblingIndex(m_initialSiblingIndex);
				}
				if (m_disableBlocksRaycastsOnDrag != null)
				{
					m_disableBlocksRaycastsOnDrag.blocksRaycasts = true;
				}
				if (m_onEndDrag != null)
				{
					m_onEndDrag(this, new DragEvent(p_event));
				}
			}
		}

		private void Start()
		{
			Canvas componentInParent = GetComponentInParent<Canvas>();
			if (componentInParent != null)
			{
				m_canvasTransform = componentInParent.GetComponent<RectTransform>();
			}
			else
			{
				Debug.LogError("uMyGUI_Draggable: no Canvas component was found in parent!");
				base.enabled = false;
			}
			m_transform = GetComponent<RectTransform>();
		}
	}
}