using System.Diagnostics;
using Shouldly;
using Xunit;

namespace ZB.MOM.WW.OtOpcUa.Host.Tests.Startup;

/// <summary>
/// #618 — a host that fails to start must END the process with a non-zero exit code and a Fatal line,
/// not linger as a half-started zombie. Spawns the built host assembly as a real child process.
/// </summary>
public sealed class FailStartExitTests
{
    [Fact]
    public async Task A_failed_start_exits_non_zero_and_logs_fatal()
    {
        var hostDll = typeof(ZB.MOM.WW.OtOpcUa.Host.Program).Assembly.Location;
        var dir = Path.GetDirectoryName(hostDll)!;

        var psi = new ProcessStartInfo("dotnet", $"\"{hostDll}\"")
        {
            WorkingDirectory = dir,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
        };
        // An invalid Akka seed address makes the cluster wiring throw before the host can ever run;
        // no external service is touched.
        psi.Environment["Cluster__Roles"] = "driver";
        psi.Environment["Cluster__SeedNodes__0"] = "not-a-valid-address";

        using var proc = Process.Start(psi)!;
        var stdout = proc.StandardOutput.ReadToEndAsync();
        var stderr = proc.StandardError.ReadToEndAsync();

        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(60));
        try { await proc.WaitForExitAsync(cts.Token); }
        catch (OperationCanceledException)
        {
            proc.Kill(entireProcessTree: true);
            Assert.Fail("host did not exit within 60 s of a failed start (#618): " + await stdout + await stderr);
        }

        var output = await stdout + await stderr;
        proc.ExitCode.ShouldNotBe(0, output);
        output.ShouldContain("terminated during startup", Case.Insensitive, "the failure must be logged as Fatal");
    }
}