using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.InputSystem;

namespace Michsky.UI.Heat
{
	public class UISway : MonoBehaviour, IPointerEnterHandler, IEventSystemHandler, IPointerExitHandler
	{
		public enum InputType
		{
			Mouse = 0,
			Touchscreen = 1
		}

		[Header("Resources")]
		[SerializeField]
		private Canvas mainCanvas;

		[SerializeField]
		private Camera mainCamera;

		[SerializeField]
		private RectTransform swayObject;

		[Header("Settings")]
		[SerializeField]
		[Range(1f, 20f)]
		private float smoothness = 10f;

		[SerializeField]
		private InputType inputType;

		private bool allowSway;

		private Vector3 cursorPos;

		private Vector2 defaultPos;

		private void Start()
		{
			defaultPos = swayObject.anchoredPosition;
			if (mainCamera == null)
			{
				mainCamera = Camera.main;
			}
			if (mainCanvas == null)
			{
				mainCanvas = GetComponentInParent<Canvas>();
			}
			if (swayObject == null)
			{
				swayObject = GetComponent<RectTransform>();
			}
		}

		private void Update()
		{
			if (allowSway && inputType == InputType.Mouse)
			{
				cursorPos = Mouse.current.position.ReadValue();
			}
			else if (allowSway && inputType == InputType.Touchscreen)
			{
				cursorPos = Touchscreen.current.position.ReadValue();
			}
			if (mainCanvas.renderMode == RenderMode.ScreenSpaceOverlay)
			{
				ProcessOverlay();
			}
			else if (mainCanvas.renderMode == RenderMode.ScreenSpaceCamera)
			{
				ProcessSSC();
			}
		}

		private void ProcessOverlay()
		{
			if (allowSway)
			{
				swayObject.position = Vector2.Lerp(swayObject.position, cursorPos, Time.unscaledDeltaTime * smoothness);
			}
			else
			{
				swayObject.localPosition = Vector2.Lerp(swayObject.localPosition, defaultPos, Time.unscaledDeltaTime * smoothness);
			}
		}

		private void ProcessSSC()
		{
			if (allowSway)
			{
				swayObject.position = Vector2.Lerp(swayObject.position, mainCamera.ScreenToWorldPoint(cursorPos), Time.unscaledDeltaTime * smoothness);
			}
			else
			{
				swayObject.localPosition = Vector2.Lerp(swayObject.localPosition, defaultPos, Time.unscaledDeltaTime * smoothness);
			}
		}

		public void OnPointerEnter(PointerEventData data)
		{
			allowSway = true;
		}

		public void OnPointerExit(PointerEventData data)
		{
			allowSway = false;
		}
	}
}