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

namespace OHM.UnityToolkit
{
	public static class UIUtils
	{
		public static void AlignToWorldObject(Transform worldObject, RectTransform uiObjectToAlign)
		{
			if (worldObject != null)
			{
				AlignToWorldPosition(worldObject.position, uiObjectToAlign);
			}
		}

		public static void AlignToWorldPosition(Vector3 targetWorldPosition, RectTransform uiObjectToAlign)
		{
			Camera cam = Camera.main;
			if (cam == null || uiObjectToAlign == null)
			{
				return;
			}
			Canvas canvas = uiObjectToAlign.GetComponentInParent<Canvas>();
			if (canvas == null)
			{
				return;
			}
			RectTransform canvasRect = canvas.GetComponent<RectTransform>();
			Vector3 viewport = cam.WorldToViewportPoint(targetWorldPosition);
			Vector2 canvasSize = canvasRect.sizeDelta;
			uiObjectToAlign.anchoredPosition = new Vector2(
				(viewport.x - canvasRect.pivot.x) * canvasSize.x,
				(viewport.y - canvasRect.pivot.y) * canvasSize.y);
		}

		public static bool IsInputBlocked(Vector2 inputPos)
		{
			var pointer = new PointerEventData(EventSystem.current);
			pointer.position = new Vector2(Input.mousePosition.x, Input.mousePosition.y);
			var results = new List<RaycastResult>();
			EventSystem.current.RaycastAll(pointer, results);
			for (int i = 0; i < results.Count; i++)
			{
				GameObject go = results[i].gameObject;
				if (go.GetComponent<Button>() != null)
				{
					return true;
				}
				if (go.GetComponent<UIInputBlocker>() != null)
				{
					return true;
				}
			}
			return false;
		}

	}
}