using System.Diagnostics;
using System.Net;
using System.Net.Sockets;
using Shouldly;
using Xunit;

namespace ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Tests;

/// <summary>
///     Review 2026-10-21 G-6: <c>ProbeTimeoutSeconds</c> was authored and compared for equivalence but
///     never consumed — the probe ran on the caller's budget alone. It now caps the probe deadline
///     (it can shorten the caller's budget, never extend it).
/// </summary>
[Trait("Category", "Unit")]
public sealed class GalaxyDriverProbeTimeoutTests
{
    /// <summary>The effective deadline is the shorter of the caller's budget and the configured cap.</summary>
    [Theory]
    [InlineData(10, 30, 10)]   // caller shorter → caller wins
    [InlineData(10, 2, 2)]     // config shorter → config caps
    [InlineData(10, 0, 10)]    // unset config → caller
    [InlineData(10, -1, 10)]   // nonsense config → caller
    [InlineData(0, 5, 1)]      // no caller budget → 1 s floor beats a longer config
    [InlineData(0, 0, 1)]      // nothing → 1 s floor
    public void EffectiveTimeout_is_the_shorter_of_caller_and_config(int callerSeconds, int configSeconds, int expectedSeconds)
        => GalaxyDriverProbe.EffectiveTimeout(TimeSpan.FromSeconds(callerSeconds), configSeconds)
            .ShouldBe(TimeSpan.FromSeconds(expectedSeconds));

    /// <summary>
    ///     Against a port that accepts TCP but never speaks gRPC, a 1 s configured cap returns long
    ///     before the caller's 20 s budget. The gRPC handshake itself does the waiting here, so this
    ///     exercises the real deadline path, not the pure helper.
    /// </summary>
    [Fact]
    public async Task Configured_cap_shortens_the_probe_against_a_silent_listener()
    {
        var listener = new TcpListener(IPAddress.Loopback, 0);
        listener.Start();
        try
        {
            var port = ((IPEndPoint)listener.LocalEndpoint).Port;
            var config = $$"""
                {
                  "Gateway": { "Endpoint": "http://127.0.0.1:{{port}}", "ApiKeySecretRef": "dev:k", "UseTls": false },
                  "MxAccess": { "ClientName": "probe-timeout" },
                  "Repository": {},
                  "Reconnect": {},
                  "ProbeTimeoutSeconds": 1
                }
                """;

            var sw = Stopwatch.StartNew();
            var result = await new GalaxyDriverProbe().ProbeAsync(config, TimeSpan.FromSeconds(20), TestContext.Current.CancellationToken);
            sw.Stop();

            result.Ok.ShouldBeFalse();
            sw.Elapsed.ShouldBeLessThan(TimeSpan.FromSeconds(10), $"the 1 s configured cap must bound the probe (message: {result.Message})");
            result.Message.ShouldNotBeNull();
            (result.Message!.Contains("timed out", StringComparison.OrdinalIgnoreCase)
             || result.Message.Contains("DeadlineExceeded", StringComparison.OrdinalIgnoreCase)
             || result.Message.Contains("handshake failed", StringComparison.OrdinalIgnoreCase))
                .ShouldBeTrue($"unexpected message: '{result.Message}'");
        }
        finally
        {
            listener.Stop();
        }
    }
}