// Copyright 2020-2025 The NATS Authors
// Licensed under the Apache License, Version 2.0

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

/// <summary>
/// Polling / assertion helpers ported from the Go test framework's checkFor and
/// related utilities.
/// </summary>
public static class CheckHelper
{
    /// <summary>
    /// Polls <paramref name="check"/> every <paramref name="interval"/> until it
    /// returns null (success) or <paramref name="timeout"/> expires.
    /// </summary>
    public static void CheckFor(
        TimeSpan timeout,
        TimeSpan interval,
        Func<string?> check)
    {
        var deadline = DateTime.UtcNow + timeout;
        string? last = null;
        while (DateTime.UtcNow < deadline)
        {
            last = check();
            if (last is null)
                return;
            Thread.Sleep(interval);
        }
        throw new Xunit.Sdk.XunitException($"CheckFor timed out after {timeout}: {last}");
    }

    /// <summary>
    /// Waits until the supplied server reports exactly <paramref name="expected"/>
    /// leaf-node connections.
    /// </summary>
    public static void CheckLeafNodeConnectedCount(object server, int expected) =>
        throw new NotImplementedException("Requires a running server instance.");
}