// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Buffers;
using System.Linq;
using Microsoft.Toolkit.HighPerformance;
using Microsoft.VisualStudio.TestTools.UnitTesting;

namespace UnitTests.HighPerformance.Extensions
{
    [TestClass]
    public class Test_ArrayPoolExtensions
    {
        [TestCategory("ArrayPoolExtensions")]
        [TestMethod]
        [ExpectedException(typeof(ArgumentOutOfRangeException))]
        public void Test_ArrayExtensions_InvalidSize()
        {
            int[] array = null;

            ArrayPool<int>.Shared.Resize(ref array, -1);
        }

        [TestCategory("ArrayPoolExtensions")]
        [TestMethod]
        public void Test_ArrayExtensions_NewArray()
        {
            int[] array = null;

            ArrayPool<int>.Shared.Resize(ref array, 10);

            Assert.IsNotNull(array);
            Assert.IsTrue(array.Length >= 10);
        }

        [TestCategory("ArrayPoolExtensions")]
        [TestMethod]
        public void Test_ArrayExtensions_SameSize()
        {
            int[] array = ArrayPool<int>.Shared.Rent(10);
            int[] backup = array;

            ArrayPool<int>.Shared.Resize(ref array, array.Length);

            Assert.AreSame(array, backup);
        }

        [TestCategory("ArrayPoolExtensions")]
        [TestMethod]
        public void Test_ArrayExtensions_Expand()
        {
            int[] array = ArrayPool<int>.Shared.Rent(16);
            int[] backup = array;

            array.AsSpan().Fill(7);

            ArrayPool<int>.Shared.Resize(ref array, 32);

            Assert.AreNotSame(array, backup);
            Assert.IsTrue(array.Length >= 32);
            Assert.IsTrue(array.AsSpan(0, 16).ToArray().All(i => i == 7));
        }

        [TestCategory("ArrayPoolExtensions")]
        [TestMethod]
        public void Test_ArrayExtensions_Shrink()
        {
            int[] array = ArrayPool<int>.Shared.Rent(32);
            int[] backup = array;

            array.AsSpan().Fill(7);

            ArrayPool<int>.Shared.Resize(ref array, 16);

            Assert.AreNotSame(array, backup);
            Assert.IsTrue(array.Length >= 16);
            Assert.IsTrue(array.AsSpan(0, 16).ToArray().All(i => i == 7));
        }

        [TestCategory("ArrayPoolExtensions")]
        [TestMethod]
        public void Test_ArrayExtensions_Clear()
        {
            int[] array = ArrayPool<int>.Shared.Rent(16);
            int[] backup = array;

            array.AsSpan().Fill(7);

            ArrayPool<int>.Shared.Resize(ref array, 0, true);

            Assert.AreNotSame(array, backup);
            Assert.IsTrue(backup.AsSpan(0, 16).ToArray().All(i => i == 0));
        }
    }
}