using System;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

namespace UIWidgets
{
	[RequireComponent(typeof(RectTransform))]
	public class RangeSliderHandle : Selectable, IDragHandler, IInitializePotentialDragHandler, ISubmitHandler, IEventSystemHandler
	{
		public Func<bool> IsHorizontal = ReturnTrue;

		public Action Decrease = DoNothing;

		public Action Increase = DoNothing;

		public Func<Vector2> PositionLimits;

		public Action<float> PositionChanged;

		public Action OnSubmit = DoNothing;

		private RectTransform rectTransform;

		public RectTransform RectTransform
		{
			get
			{
				if (rectTransform == null)
				{
					rectTransform = base.transform as RectTransform;
				}
				return rectTransform;
			}
		}

		private bool CanDrag(PointerEventData eventData)
		{
			return IsActive() && IsInteractable() && eventData.button == PointerEventData.InputButton.Left;
		}

		private static bool ReturnTrue()
		{
			return true;
		}

		private static void DoNothing()
		{
		}

		void ISubmitHandler.OnSubmit(BaseEventData eventData)
		{
			OnSubmit();
		}

		public virtual void OnDrag(PointerEventData eventData)
		{
			Vector2 localPoint;
			if (CanDrag(eventData) && RectTransformUtility.ScreenPointToLocalPointInRectangle(RectTransform, eventData.position, eventData.pressEventCamera, out localPoint))
			{
				Vector2 vector = PositionLimits();
				Vector3 vector2 = RectTransform.anchoredPosition;
				if (IsHorizontal())
				{
					vector2.x = Mathf.Clamp(vector2.x + localPoint.x, vector.x, vector.y);
				}
				else
				{
					vector2.y = Mathf.Clamp(vector2.y + localPoint.y, vector.x, vector.y);
				}
				if (IsNewPosition(vector2))
				{
					RectTransform.anchoredPosition = vector2;
					PositionChanged((!IsHorizontal()) ? vector2.y : vector2.x);
				}
			}
		}

		private bool IsNewPosition(Vector3 pos)
		{
			if (IsHorizontal())
			{
				return RectTransform.anchoredPosition.x != pos.x;
			}
			return RectTransform.anchoredPosition.y != pos.y;
		}

		public virtual void OnInitializePotentialDrag(PointerEventData eventData)
		{
			eventData.useDragThreshold = false;
		}

		public override void OnMove(AxisEventData eventData)
		{
			if (!IsActive() || !IsInteractable())
			{
				base.OnMove(eventData);
				return;
			}
			switch (eventData.moveDir)
			{
			case MoveDirection.Left:
				if (IsHorizontal() && FindSelectableOnLeft() == null)
				{
					Decrease();
				}
				else
				{
					base.OnMove(eventData);
				}
				break;
			case MoveDirection.Right:
				if (IsHorizontal() && FindSelectableOnRight() == null)
				{
					Increase();
				}
				else
				{
					base.OnMove(eventData);
				}
				break;
			case MoveDirection.Up:
				if (!IsHorizontal() && FindSelectableOnUp() == null)
				{
					Increase();
				}
				else
				{
					base.OnMove(eventData);
				}
				break;
			case MoveDirection.Down:
				if (!IsHorizontal() && FindSelectableOnDown() == null)
				{
					Decrease();
				}
				else
				{
					base.OnMove(eventData);
				}
				break;
			}
		}

		public override Selectable FindSelectableOnLeft()
		{
			if (base.navigation.mode == Navigation.Mode.Automatic && IsHorizontal())
			{
				return null;
			}
			return base.FindSelectableOnLeft();
		}

		public override Selectable FindSelectableOnRight()
		{
			if (base.navigation.mode == Navigation.Mode.Automatic && IsHorizontal())
			{
				return null;
			}
			return base.FindSelectableOnRight();
		}

		public override Selectable FindSelectableOnUp()
		{
			if (base.navigation.mode == Navigation.Mode.Automatic && !IsHorizontal())
			{
				return null;
			}
			return base.FindSelectableOnUp();
		}

		public override Selectable FindSelectableOnDown()
		{
			if (base.navigation.mode == Navigation.Mode.Automatic && !IsHorizontal())
			{
				return null;
			}
			return base.FindSelectableOnDown();
		}
	}
}