/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

using System.Collections;
using System.Collections.Generic;

namespace Elasticsearch.Net.Connection.Thrift.Collections
{
	public class THashSet<T> : ICollection<T>
	{
#if NET_2_0
		TDictSet<T> set = new TDictSet<T>();
#else
		private readonly HashSet<T> set = new HashSet<T>();
#endif

		public int Count
		{
			get { return set.Count; }
		}

		public bool IsReadOnly
		{
			get { return false; }
		}

		public void Add(T item)
		{
			set.Add(item);
		}

		public void Clear()
		{
			set.Clear();
		}

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

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

		public IEnumerator GetEnumerator()
		{
			return set.GetEnumerator();
		}

		IEnumerator<T> IEnumerable<T>.GetEnumerator()
		{
			return ((IEnumerable<T>) set).GetEnumerator();
		}

		public bool Remove(T item)
		{
			return set.Remove(item);
		}

#if NET_2_0
		private class TDictSet<V> : ICollection<V>
		{
			Dictionary<V, TDictSet<V>> dict = new Dictionary<V, TDictSet<V>>();

			public int Count
			{
				get { return dict.Count; }
			}

			public bool IsReadOnly
			{
				get { return false; }
			}

			public IEnumerator GetEnumerator()
			{
				return ((IEnumerable)dict.Keys).GetEnumerator();
			}

			IEnumerator<V> IEnumerable<V>.GetEnumerator()
			{
				return dict.Keys.GetEnumerator();
			}

			public bool Add(V item)
			{
				if (!dict.ContainsKey(item))
				{
					dict[item] = this;
					return true;
				}

				return false;
			}

			void ICollection<V>.Add(V item)
			{
				Add(item);
			}

			public void Clear()
			{
				dict.Clear();
			}

			public bool Contains(V item)
			{
				return dict.ContainsKey(item);
			}

			public void CopyTo(V[] array, int arrayIndex)
			{
				dict.Keys.CopyTo(array, arrayIndex);
			}

			public bool Remove(V item)
			{
				return dict.Remove(item);
			}
		}
#endif
	}
}