using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.Events;

namespace UIWidgets
{
	public abstract class CenteredSliderBase<T> : MonoBehaviour, IPointerClickHandler, IEventSystemHandler where T : struct
	{
		[Serializable]
		public class OnChangeEvent : UnityEvent<T>
		{
		}

		[SerializeField]
		protected T _value;

		[SerializeField]
		protected T step;

		[SerializeField]
		protected T limitMin;

		[SerializeField]
		protected T limitMax;

		[SerializeField]
		protected RangeSliderHandle handle;

		protected RectTransform handleRect;

		[SerializeField]
		protected RectTransform UsableRangeRect;

		[SerializeField]
		protected RectTransform FillRect;

		protected RectTransform rangeSliderRect;

		public OnChangeEvent OnValuesChange = new OnChangeEvent();

		public UnityEvent OnChange = new UnityEvent();

		public bool WholeNumberOfSteps;

		private bool isInitCalled;

		public T Value
		{
			get
			{
				return _value;
			}
			set
			{
				SetValue(value);
			}
		}

		public T Step
		{
			get
			{
				return step;
			}
			set
			{
				step = value;
			}
		}

		public T LimitMin
		{
			get
			{
				return limitMin;
			}
			set
			{
				limitMin = value;
				SetValue(_value);
			}
		}

		public T LimitMax
		{
			get
			{
				return limitMax;
			}
			set
			{
				limitMax = value;
				SetValue(_value);
			}
		}

		public RectTransform HandleRect
		{
			get
			{
				if (handle != null && handleRect == null)
				{
					handleRect = handle.transform as RectTransform;
				}
				return handleRect;
			}
		}

		public RangeSliderHandle Handle
		{
			get
			{
				return handle;
			}
			set
			{
				SetHandle(value);
			}
		}

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

		protected virtual void Init()
		{
			if (!isInitCalled)
			{
				isInitCalled = true;
				SetHandle(handle);
				UpdateHandle();
				UpdateFill();
			}
		}

		protected virtual void SetValue(T value)
		{
			if (!EqualityComparer<T>.Default.Equals(_value, InBounds(value)))
			{
				_value = InBounds(value);
				UpdateHandle();
				OnValuesChange.Invoke(_value);
				OnChange.Invoke();
			}
		}

		protected virtual void SetHandle(RangeSliderHandle value)
		{
			handle = value;
			handle.IsHorizontal = IsHorizontal;
			handle.PositionLimits = PositionLimits;
			handle.PositionChanged = UpdateValue;
			handle.Increase = Increase;
			handle.Decrease = Decrease;
		}

		protected virtual void Start()
		{
			Init();
		}

		public void SetLimit(T min, T max)
		{
			limitMin = min;
			limitMax = max;
			LimitMin = limitMin;
			LimitMax = limitMax;
		}

		protected virtual bool IsHorizontal()
		{
			return true;
		}

		protected float RangeSize()
		{
			return (!IsHorizontal()) ? UsableRangeRect.rect.height : UsableRangeRect.rect.width;
		}

		protected float HandleSize()
		{
			return (!IsHorizontal()) ? HandleRect.rect.height : HandleRect.rect.width;
		}

		protected void UpdateValue(float position)
		{
			_value = PositionToValue(position - GetStartPoint());
			UpdateHandle();
			OnValuesChange.Invoke(_value);
			OnChange.Invoke();
		}

		protected abstract float ValueToPosition(T value);

		protected abstract T PositionToValue(float position);

		protected float GetStartPoint()
		{
			return (!IsHorizontal()) ? ((0f - UsableRangeRect.sizeDelta.y) / 2f) : ((0f - UsableRangeRect.sizeDelta.x) / 2f);
		}

		protected abstract Vector2 PositionLimits();

		protected abstract T InBounds(T value);

		protected abstract void Increase();

		protected abstract void Decrease();

		protected void UpdateHandle()
		{
			Vector2 anchoredPosition = HandleRect.anchoredPosition;
			if (IsHorizontal())
			{
				anchoredPosition.x = ValueToPosition(_value) + HandleRect.rect.width * (HandleRect.pivot.x - 0.5f);
			}
			else
			{
				anchoredPosition.y = ValueToPosition(_value) + HandleRect.rect.width * (HandleRect.pivot.x - 0.5f);
			}
			HandleRect.anchoredPosition = anchoredPosition;
			UpdateFill();
		}

		protected abstract bool IsPositiveValue();

		protected virtual void UpdateFill()
		{
			FillRect.anchorMin = new Vector2(0.5f, 0.5f);
			FillRect.anchorMax = new Vector2(0.5f, 0.5f);
			if (IsHorizontal())
			{
				if (IsPositiveValue())
				{
					FillRect.pivot = new Vector2(0f, 0.5f);
					FillRect.SetSizeWithCurrentAnchors(RectTransform.Axis.Horizontal, HandleRect.localPosition.x - UsableRangeRect.localPosition.x);
				}
				else
				{
					FillRect.pivot = new Vector2(1f, 0.5f);
					FillRect.SetSizeWithCurrentAnchors(RectTransform.Axis.Horizontal, UsableRangeRect.localPosition.x - HandleRect.localPosition.x);
				}
			}
			else if (IsPositiveValue())
			{
				FillRect.pivot = new Vector2(0.5f, 0f);
				FillRect.SetSizeWithCurrentAnchors(RectTransform.Axis.Vertical, HandleRect.localPosition.y - UsableRangeRect.localPosition.y);
			}
			else
			{
				FillRect.pivot = new Vector2(0.5f, 1f);
				FillRect.SetSizeWithCurrentAnchors(RectTransform.Axis.Vertical, UsableRangeRect.localPosition.y - HandleRect.localPosition.y);
			}
		}

		public virtual void OnPointerClick(PointerEventData eventData)
		{
			Vector2 localPoint;
			if (RectTransformUtility.ScreenPointToLocalPointInRectangle(UsableRangeRect, eventData.position, eventData.pressEventCamera, out localPoint))
			{
				localPoint -= UsableRangeRect.rect.position;
				float position = ((!IsHorizontal()) ? localPoint.y : localPoint.x) + GetStartPoint();
				UpdateValue(position);
			}
		}
	}
}