using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
#if UNITY_EDITOR
using UnityEditor;
#endif
namespace Rellac.Windows
{
	public static class GUIWindowUtils
	{
#if UNITY_EDITOR
		[MenuItem("GameObject/UI/Window")]
		public static void InstantiateWindow()
		{
			NewWindow();
		}
#endif

		public static GameObject NewWindow()
		{
			Object prefab = Resources.Load("WindowUIComponent");
			Canvas canvas = GameObject.FindObjectOfType<Canvas>();
			if (canvas == null)
			{
				// Create default canvas
				GameObject newCanvas = new GameObject("Canvas");
				canvas = newCanvas.AddComponent<Canvas>();
				canvas.renderMode = RenderMode.ScreenSpaceOverlay;
				newCanvas.AddComponent<CanvasScaler>();
				newCanvas.AddComponent<GraphicRaycaster>();
				if (GameObject.FindObjectOfType<EventSystem>() == null)
				{
					// Create defalut EventSystem
					new GameObject("EventSystem").AddComponent<EventSystem>(). // create new GameObject with EventSystem
						gameObject.AddComponent<StandaloneInputModule>() // add Input Module
#if UNITY_5_3_OR_NEWER
						; // we don't need the Touch Input Module at 5.3+
#else
						.gameObject.AddComponent<TouchInputModule>();
#endif
				}
			}
			GameObject go = (GameObject)GameObject.Instantiate(prefab);
			go.transform.SetParent(canvas.transform);
			go.transform.localPosition = Vector2.zero;
			go.name = "Window";
			return go;
		}

		public static void SetPivot(this RectTransform rectTransform, Vector2 pivot)
		{
			if (rectTransform == null) return;

			Vector2 size = rectTransform.rect.size;
			Vector2 deltaPivot = rectTransform.pivot - pivot;
			Vector3 deltaPosition = new Vector3(deltaPivot.x * size.x, deltaPivot.y * size.y);
			rectTransform.pivot = pivot;
			rectTransform.localPosition -= deltaPosition;
		}

		public static Vector3 MousePosition()
        {
            var mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            return new Vector3(mousePos.x, mousePos.y, 0);
        }
	}
}