/* SPDX-License-Identifier: Apache-2.0
*
* The OpenSearch Contributors require contributions made to
* this file be licensed under the Apache-2.0 license or a
* compatible open source license.
*/
/*
* Modifications Copyright OpenSearch Contributors. See
* GitHub history for details.
*
*  Licensed to Elasticsearch B.V. under one or more contributor
*  license agreements. See the NOTICE file distributed with
*  this work for additional information regarding copyright
*  ownership. Elasticsearch B.V. 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;
using System.Collections.Generic;
using System.Collections.ObjectModel;

namespace Tests.Core.Extensions
{
	public static class EnumerableExtensions
	{
		public static IEnumerable<IEnumerable<T>> Partition<T>(this IEnumerable<T> source, int size)
		{
			T[] array = null;
			var count = 0;

			foreach (var item in source)
			{
				if (array == null) array = new T[size];
				array[count] = item;
				count++;
				if (count == size)
				{
					yield return new ReadOnlyCollection<T>(array);

					array = null;
					count = 0;
				}
			}

			if (array != null)
			{
				Array.Resize(ref array, count);
				yield return new ReadOnlyCollection<T>(array);
			}
		}
	}
}