using UnityEngine;
using System.Collections;

namespace Utility
{
	public class NGUIGridAutoLoop : MonoBehaviour 
	{
		public enum LoopDircetion 
		{
			LeftToRight,
			RightToLeft,
			TopToDown,
			DownToTop,
		}

		public enum LoopType 
		{
			Horizontal,
			Vertical,
		}

		public delegate void OnLoopDelegate (LoopDircetion direction);

		public LoopType m_looptype = LoopType.Vertical;
		public OnLoopDelegate m_loopCallback;

		private UIGrid m_grid;
		private Transform m_gridTrans;
		private float validWidth;
		private float validHeight;

		private void Awake () 
		{
			m_grid = transform.GetComponentInChildren<UIGrid> ();
			if(m_grid != null)
				m_gridTrans = m_grid.transform;
		}

		private void Start () 
		{
			if (m_grid == null || m_gridTrans.childCount == 0) {
				Debug.LogError ("GridAutoLoop Error");
				return;
			}

			validWidth = m_grid.transform.childCount * m_grid.cellWidth;
			validHeight = m_grid.transform.childCount * m_grid.cellHeight;

			var backupGo = GameObject.Instantiate (m_grid.transform.GetChild(0));
			backupGo.gameObject.SetActive (true);
			backupGo.transform.SetParent (m_grid.transform, false);
		}

		private void LateUpdate () 
		{
			if (m_looptype == LoopType.Vertical) {
				while (m_grid.transform.localPosition.y < 0) {
					m_grid.transform.localPosition += new Vector3 (0, validHeight, 0);
					if (m_loopCallback != null)
						m_loopCallback (LoopDircetion.TopToDown);
				}

				while (m_grid.transform.localPosition.y > validHeight) {
					m_grid.transform.localPosition -= new Vector3 (0, validHeight, 0);
					if (m_loopCallback != null)
						m_loopCallback (LoopDircetion.DownToTop);
				}
			} else if (m_looptype == LoopType.Horizontal) {
				while (m_grid.transform.localPosition.x > 0) {
					m_grid.transform.localPosition -= new Vector3 (validWidth, 0, 0);
					if (m_loopCallback != null)
						m_loopCallback (LoopDircetion.LeftToRight);
				}

				while (m_grid.transform.localPosition.x < -validWidth) {
					m_grid.transform.localPosition += new Vector3 (validWidth, 0, 0);
					if (m_loopCallback != null)
						m_loopCallback (LoopDircetion.RightToLeft);
				}
			}
		}
	}

}