// Copyright 2012-2025 The NATS Authors
// Licensed under the Apache License, Version 2.0

using Xunit.Abstractions;

namespace ZB.MOM.NatsNet.Server.IntegrationTests.Helpers;

/// <summary>
/// Stub helper for creating multi-server NATS clusters in integration tests.
/// In the Go test suite, this corresponds to createJetStreamCluster(t, numServers, name) and
/// createJetStreamSuperCluster(t, numClusters, numServersPerCluster).
///
/// This stub is a placeholder until cluster orchestration is implemented.
/// Tests using this helper will skip unless NATS_INTEGRATION_ENABLED=true.
/// </summary>
public sealed class TestCluster : IDisposable
{
    private readonly ITestOutputHelper _output;

    /// <summary>Number of servers in the cluster.</summary>
    public int ServerCount { get; }

    /// <summary>Cluster name.</summary>
    public string Name { get; }

    /// <summary>URL of a random server in the cluster (stub returns the default URL).</summary>
    public string RandomServerUrl =>
        Environment.GetEnvironmentVariable("NATS_TEST_SERVER_URL") ?? "nats://localhost:4222";

    private TestCluster(ITestOutputHelper output, int serverCount, string name)
    {
        _output = output;
        ServerCount = serverCount;
        Name = name;
    }

    /// <summary>
    /// Creates a stub JetStream cluster. Throws NotSupportedException when integration is disabled.
    /// Corresponds to createJetStreamCluster(t, numServers, name) in Go tests.
    /// </summary>
    public static TestCluster CreateJetStreamCluster(int numServers, string name, ITestOutputHelper output)
    {
        if (!IntegrationTestBase.IntegrationEnabled)
            throw new NotSupportedException(IntegrationTestBase.SkipMessage);

        output.WriteLine($"Creating JetStream cluster '{name}' with {numServers} servers (stub)");
        return new TestCluster(output, numServers, name);
    }

    /// <summary>
    /// Creates a stub JetStream super-cluster.
    /// Corresponds to createJetStreamSuperCluster(t, numClusters, numServers) in Go tests.
    /// </summary>
    public static TestCluster CreateJetStreamSuperCluster(int numClusters, int numServersPerCluster, ITestOutputHelper output)
    {
        if (!IntegrationTestBase.IntegrationEnabled)
            throw new NotSupportedException(IntegrationTestBase.SkipMessage);

        output.WriteLine($"Creating JetStream super-cluster with {numClusters} clusters x {numServersPerCluster} servers (stub)");
        return new TestCluster(output, numClusters * numServersPerCluster, $"SuperCluster({numClusters}x{numServersPerCluster})");
    }

    public void Dispose()
    {
        _output.WriteLine($"Shutting down cluster '{Name}'");
    }
}