namespace ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.IntegrationTests;

/// <summary>
///     Fixture for the reverse-connect variant of opc-plc (PR-11). Unlike the
///     dial-mode <see cref="OpcPlcFixture"/>, the simulator here is the dialer:
///     it reaches OUT to the test runner's listener URL on
///     <c>opc.tcp://host.docker.internal:4844</c>. The fixture's job is to
///     advertise the listener URL the test should bind and provide a clear
///     skip reason when the docker-compose service isn't running.
/// </summary>
/// <remarks>
///     <para>
///         <b>Why no port-probe</b>: the conventional fixture probes the simulator's
///         server port to detect docker-up. In reverse-connect the simulator opens
///         no inbound port — it's a pure dialer — so a probe would always fail.
///         Tests that want a hard skip should look at <see cref="SkipReason"/>
///         which is set from the <c>OPCUA_RC_SIM</c> env var (any value =
///         "simulator running"; absent = skip).
///     </para>
///     <para>
///         The "shared listener URL" model is enforced by the driver's
///         <c>ReverseConnectListener</c> singleton — multiple smoke tests in the
///         same xunit assembly share one listener instance even if they run in
///         parallel. Tests should pick distinct <c>ExpectedServerUri</c> values to
///         demultiplex inbound connections.
///     </para>
/// </remarks>
public sealed class OpcPlcReverseConnectFixture : IAsyncDisposable
{
    private const string DefaultListenerUrl = "opc.tcp://0.0.0.0:4844";
    private const string EnvVar = "OPCUA_RC_SIM";

    /// <summary>The listener URL the driver should bind for incoming reverse-connect dials.</summary>
    public string ListenerUrl { get; } = DefaultListenerUrl;

    /// <summary>Skip reason when the reverse-connect simulator isn't available; null when ready.</summary>
    public string? SkipReason { get; }

    public OpcPlcReverseConnectFixture()
    {
        if (string.IsNullOrWhiteSpace(Environment.GetEnvironmentVariable(EnvVar)))
        {
            SkipReason =
                $"Reverse-connect smoke skipped — set {EnvVar}=1 once `docker compose -f Docker/docker-compose.yml up opc-plc-rc` is healthy. " +
                "The dialer needs host.docker.internal to reach this machine — verify Docker Desktop's network mode supports it.";
        }
    }

    public ValueTask DisposeAsync() => ValueTask.CompletedTask;
}

[Xunit.CollectionDefinition(Name)]
public sealed class OpcPlcReverseConnectCollection : Xunit.ICollectionFixture<OpcPlcReverseConnectFixture>
{
    public const string Name = "OpcPlcReverseConnect";
}