// 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.IO;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Host;
using Xunit;
 
namespace Microsoft.CodeAnalysis.UnitTests.WorkspaceServices;
 
/// <remarks>
/// Tests are inherited from <see cref="AbstractPersistentStorageTests"/>.  That way we can
/// write tests once and have them run against all <see cref="IPersistentStorageService"/>
/// implementations.
/// </remarks>
public sealed class SQLiteV2PersistentStorageTests : AbstractPersistentStorageTests
{
    [Fact]
    public async Task TestCrashInNewConnection()
    {
        var solution = CreateOrOpenSolution(nullPaths: true);
 
        var hitInjector = false;
        var faultInjector = new PersistentStorageFaultInjector(
            onNewConnection: () =>
            {
                hitInjector = true;
                throw new Exception();
            },
            onFatalError: e => throw e);
 
        // Because instantiating the connection will fail, we will not get back
        // a working persistent storage. We are testing a fault recovery code path.
        var storage = await GetStorageAsync(solution, faultInjector: faultInjector, throwOnFailure: false);
        using (var memStream = new MemoryStream())
        using (var streamWriter = new StreamWriter(memStream))
        {
            streamWriter.WriteLine("contents");
            streamWriter.Flush();
 
            memStream.Position = 0;
            await storage.WriteStreamAsync("temp", memStream);
            var readStream = await storage.ReadStreamAsync("temp");
 
            // Because we don't have a real storage service, we should get back
            // null even when trying to read something we just wrote.
            Assert.Null(readStream);
        }
 
        Assert.True(hitInjector);
 
        // Ensure we don't get a crash due to SqlConnection's finalizer running.
        for (var i = 0; i < 10; i++)
        {
            GC.Collect();
            GC.WaitForPendingFinalizers();
        }
    }
 
    private sealed class PersistentStorageFaultInjector : IPersistentStorageFaultInjector
    {
        private readonly Action? _onNewConnection;
        private readonly Action<Exception>? _onFatalError;
 
        public PersistentStorageFaultInjector(
            Action? onNewConnection = null,
            Action<Exception>? onFatalError = null)
        {
            _onNewConnection = onNewConnection;
            _onFatalError = onFatalError;
        }
 
        public void OnNewConnection()
            => _onNewConnection?.Invoke();
 
        public void OnFatalError(Exception ex)
            => _onFatalError?.Invoke(ex);
    }
}