#if UNITY_5_3_OR_NEWER
using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace RocketUtils
{
    [Serializable]
    public class ObservableList<T> : ICollection<T>
	{
        public event Action Changed;

        [SerializeField] private List<T> _list;		

		public ObservableList()
        {
            _list = new List<T>();
        }

		public ObservableList(ObservableList<T> newList)
		{
			_list = new List<T>();

			foreach (var listItem in newList)
			{
				_list.Add(listItem);

				IObservableModel observableItem = listItem as IObservableModel;

				if (observableItem != null)
					observableItem.PropertyChanged += RaiseChangedEvent;
			}
		}

		~ObservableList()
	    {
			Clear();
	    }

		#region ICollection Related
		public int Count
		{
			get { return _list.Count; }
		}

		public bool IsReadOnly
		{
			get { return false; }
		}

		//Only raise changed event once.
		public void Clear()
		{
			for (int i = _list.Count - 1; i >= 0; i--)
			{
				IObservableModel observableItem = _list[i] as IObservableModel;
				if (observableItem != null)
					observableItem.PropertyChanged -= RaiseChangedEvent;

				_list.Remove(_list[i]);
			}

			RaiseChangedEvent();
		}

		public bool Contains(T item)
		{
			return _list.Contains(item);
		}

		public void CopyTo(T[] array, int arrayIndex)
		{
			_list.CopyTo(array, arrayIndex);
		}		
		#endregion

		public void Add(T item)
        {
            _list.Add(item);
	        RaiseChangedEvent();

	        IObservableModel observableItem = item as IObservableModel;
	        if (observableItem != null)
		        observableItem.PropertyChanged += RaiseChangedEvent;
        }

		public bool Remove(T item)
		{
			if (!_list.Remove(item))
				return false;

			RaiseChangedEvent();

			IObservableModel observableItem = item as IObservableModel;
			if (observableItem != null)
				observableItem.PropertyChanged -= RaiseChangedEvent;

			return true;
		}

		public void RemoveAt(int index)
		{			
			_list.RemoveAt(index);

			RaiseChangedEvent();
		}

		public T this[int key]
        {
            get { return _list[key]; }
            set
            {
                _list[key] = value;
                if (Changed != null) Changed();
            }
        }

		public IEnumerator<T> GetEnumerator()
		{
			return _list.GetEnumerator();
		}

		IEnumerator IEnumerable.GetEnumerator()
		{
			return _list.GetEnumerator();
		}

		private void RaiseChangedEvent()
		{
			if (Changed != null)
				Changed.Invoke();
		}
    }	
}
#endif