using NUnit.Framework;
using System;
using Assert = Lucene.Net.TestFramework.Assert;

namespace Lucene.Net.Util
{
    /*
     * 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.
     */

    /// <summary>
    /// Check large and special graphs.
    /// </summary>
    [TestFixture]
    public class TestRamUsageEstimatorOnWildAnimals : LuceneTestCase
    {
#if FEATURE_STACKOVERFLOWEXCEPTION__ISCATCHABLE // StackOverflowException cannot be caught in .NET Core. This test does not apply.
        public class ListElement
        {
            internal ListElement Next;
        }

        [Test]
        public virtual void TestOverflowMaxChainLength()
        {
            int UPPERLIMIT = 100000;
            int lower = 0;
            int upper = UPPERLIMIT;

            while (lower + 1 < upper)
            {
                int mid = (lower + upper) / 2;
                try
                {
                    ListElement first = new ListElement();
                    ListElement last = first;
                    for (int i = 0; i < mid; i++)
                    {
                        last = (last.Next = new ListElement());
                    }
                    RamUsageEstimator.SizeOf(first); // cause SOE or pass.
                    lower = mid;
                }
                catch (Exception e) when (e.IsStackOverflowError())
                {
                    upper = mid;
                }
            }

            if (lower + 1 < UPPERLIMIT)
            {
                Assert.Fail("Max object chain length till stack overflow: " + lower);
            }
        }
#endif
    }
}
