/* 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
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*/

using System;
using System.Collections.Generic;
using OpenSearch.OpenSearch.Xunit.XunitPlumbing;
using FluentAssertions;
using OpenSearch.Client;
using Tests.Core.ManagedOpenSearch.Clusters;

namespace Tests.Document.Multiple.BulkAll
{
	public class BulkAllDeallocationApiTests : BulkAllApiTestsBase
	{
		public BulkAllDeallocationApiTests(IntrusiveOperationCluster cluster) : base(cluster) { }

		[I] public void ForEachAsyncReleasesProcessedItemsInMemory()
		{
			WeakReference<SmallObject> deallocReference = null;
			SmallObject obj = null;

			var lazyCollection = GetLazyCollection(
				weakRef => deallocReference = weakRef,
				delegate { }, //...
				delegate { }, //Making sure that all of the objects have gone through pipeline
				delegate { }, //so that the first one can be deallocated
				delegate { }, //Various GC roots prevent several of previous (2 or 3)
				delegate { }, //items in the lazy Enumerable from deallocation during forced GC
				delegate { }, //...
				delegate
				{
					GC.Collect(2, GCCollectionMode.Forced, true);
					deallocReference.TryGetTarget(out obj);
				}
			);

			var index = CreateIndexName();
			var observableBulk = Client.BulkAll(lazyCollection, f => f
				.MaxDegreeOfParallelism(1)
				.Size(1)
				.Index(index)
				.BufferToBulk((r, buffer) => r.IndexMany(buffer)));

			observableBulk.Wait(TimeSpan.FromSeconds(30), delegate { });

			deallocReference.Should().NotBeNull();
			obj.Should().BeNull();
		}

		private IEnumerable<SmallObject> GetLazyCollection(params Action<WeakReference<SmallObject>>[] getFirstObjectCallBack)
		{
			var counter = 0;
			foreach (var callback in getFirstObjectCallBack)
			{
				var obj = new SmallObject { Id = ++counter };
				callback(new WeakReference<SmallObject>(obj));
				yield return obj;
			}
		}
	}
}