// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;

namespace Microsoft.DotNet.Arcade.Sdk;

// Not opted into multithreading: GetRegisteredTaskObject followed by RegisterTaskObject is not
// atomic, so two instances with the same Text running concurrently in one node can both miss the
// sentinel and both log the error, defeating the single-error contract. Opting in requires an
// atomic register-if-absent primitive, which the BuildEngine task-object API does not offer.
public sealed class SingleError : Task
{
    private static readonly string s_cacheKeyPrefix = "SingleError-F88E25C6-1488-4E81-A458-A0921794E6E3:";

    [Required]
    public string Text { get; set; }

    public override bool Execute()
    {
        var key = s_cacheKeyPrefix + Text;

        var errorReportedSentinel = BuildEngine4.GetRegisteredTaskObject(key, RegisteredTaskObjectLifetime.Build);
        if (errorReportedSentinel != null)
        {
            Log.LogMessage(MessageImportance.Low, Text);
            return false;
        }

        BuildEngine4.RegisterTaskObject(key, new object(), RegisteredTaskObjectLifetime.Build, allowEarlyCollection: true);
        Log.LogError(Text);
        return false;
    }
}