using System;
using System.Runtime.InteropServices;

namespace UnityEngine.XR.iOS
{
	public class UnityARUtility
	{
		private MeshCollider meshCollider; //declared to avoid code stripping of class
		private MeshFilter meshFilter; //declared to avoid code stripping of class
		private static GameObject planePrefab = null;

		public static void InitializePlanePrefab(GameObject go)
		{
			planePrefab = go;
		}
		
		public static GameObject CreatePlaneInScene(ARPlaneAnchor arPlaneAnchor)
		{
			GameObject plane;
			if (planePrefab != null) {
				plane = GameObject.Instantiate(planePrefab);
			} else {
				plane = new GameObject (); //put in a blank gameObject to get at least a transform to manipulate
			}

			plane.name = arPlaneAnchor.identifier;

			return UpdatePlaneWithAnchorTransform(plane, arPlaneAnchor);

		}

		public static GameObject UpdatePlaneWithAnchorTransform(GameObject plane, ARPlaneAnchor arPlaneAnchor)
		{
			
			//do coordinate conversion from ARKit to Unity
			plane.transform.position = UnityARMatrixOps.GetPosition (arPlaneAnchor.transform);
			plane.transform.rotation = UnityARMatrixOps.GetRotation (arPlaneAnchor.transform);

			MeshFilter mf = plane.GetComponentInChildren<MeshFilter> ();

			if (mf != null) {
                //since our plane mesh is actually 10mx10m in the world, we scale it here by 0.1f
                mf.gameObject.transform.localScale = new Vector3(arPlaneAnchor.extent.x * 0.1f ,arPlaneAnchor.extent.y * 0.1f ,arPlaneAnchor.extent.z * 0.1f );

                //convert our center position to unity coords
                mf.gameObject.transform.localPosition = new Vector3(arPlaneAnchor.center.x,arPlaneAnchor.center.y, -arPlaneAnchor.center.z);
			}

			return plane;
		}

	}
}

