using Akka.Actor;
using Akka.Configuration;
using Shouldly;
using Xunit;

namespace ZB.MOM.WW.OtOpcUa.Cluster.Tests;

/// <summary>
///     Asserts the remoting frame-size canary and the DistributedPubSub extension that are actually
///     <b>in force</b> on a real <see cref="ActorSystem"/> built from the shipped base config.
/// </summary>
/// <remarks>
///     Asserting the <c>akka.conf</c> text instead would pass while a competing HOCON fragment
///     silently overrode the value — the failure mode recorded at length in
///     <c>ServiceCollectionExtensions.BuildDowningHocon</c> and pinned the same way by
///     <c>SplitBrainResolverActivationTests</c>. In this codebase the effective value is the only
///     one worth asserting.
/// </remarks>
public class MeshTransportHoconTests : IDisposable
{
    private readonly ActorSystem _sys;

    public MeshTransportHoconTests()
    {
        var config = ConfigurationFactory
            .ParseString("akka.remote.dot-netty.tcp.port = 0\nakka.cluster.seed-nodes = []")
            .WithFallback(HoconLoader.LoadBaseConfig());
        _sys = ActorSystem.Create("mesh-hocon-probe", config);
    }

    [Fact]
    public void Oversized_frames_are_logged_rather_than_dropped_silently()
    {
        // The sister project's most expensive incident. A message over the frame limit is dropped
        // WITHOUT tearing down the association: heartbeats keep flowing, the node still reports
        // healthy, and the only symptom is a command that never arrived. log-frame-size-exceeding
        // converts that silence into a log line naming the offending size.
        _sys.Settings.Config.GetByteSize("akka.remote.dot-netty.tcp.maximum-frame-size").ShouldBe(128000);
        _sys.Settings.Config.GetByteSize("akka.remote.dot-netty.tcp.log-frame-size-exceeding").ShouldBe(32000);
    }

    [Fact]
    public void Distributed_pub_sub_extension_is_registered_at_startup()
    {
        // DPS is PAIR-LOCAL and survives the cross-mesh transport's deletion: it carries
        // MeshTransport:Mode = Dps (the single-mesh default), the node-local alarm-command publishes
        // and the node<->node redundancy-state probe leg. Losing it would break far more than deploys.
        _sys.Settings.Config.GetStringList("akka.extensions")
            .ShouldContain(s => s.Contains("DistributedPubSubExtensionProvider"));
    }

    public void Dispose()
    {
        _sys.Terminate().Wait(TimeSpan.FromSeconds(5));
        GC.SuppressFinalize(this);
    }
}