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

using System.Runtime.InteropServices;
using Shouldly;
using ZB.MOM.NatsNet.Server.Internal;

namespace ZB.MOM.NatsNet.Server.Tests.Internal;

/// <summary>
/// Tests for SignalHandler — mirrors tests from server/signal_test.go.
/// </summary>
public class SignalHandlerTests
{
    /// <summary>
    /// Mirrors CommandToSignal mapping tests.
    /// </summary>
    [Fact] // T:3158
    public void CommandToUnixSignal_ShouldMapCorrectly()
    {
        SignalHandler.CommandToUnixSignal(ServerCommand.Stop).ShouldBe(UnixSignal.SigKill);
        SignalHandler.CommandToUnixSignal(ServerCommand.Quit).ShouldBe(UnixSignal.SigInt);
        SignalHandler.CommandToUnixSignal(ServerCommand.Reopen).ShouldBe(UnixSignal.SigUsr1);
        SignalHandler.CommandToUnixSignal(ServerCommand.Reload).ShouldBe(UnixSignal.SigHup);
    }

    /// <summary>
    /// Mirrors SetProcessName test.
    /// </summary>
    [Fact] // T:3155
    public void SetProcessName_ShouldNotThrow()
    {
        Should.NotThrow(() => SignalHandler.SetProcessName("test-server"));
    }

    /// <summary>
    /// Verify IsWindowsService returns false on non-Windows.
    /// </summary>
    [Fact] // T:3149
    public void IsWindowsService_ShouldReturnFalse()
    {
        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            return; // Skip on Windows
        SignalHandler.IsWindowsService().ShouldBeFalse();
    }

    /// <summary>
    /// Mirrors Run — service.go Run() simply invokes the start function.
    /// </summary>
    [Fact] // T:3148
    public void Run_ShouldInvokeStartAction()
    {
        var called = false;
        SignalHandler.Run(() => called = true);
        called.ShouldBeTrue();
    }

    /// <summary>
    /// ProcessSignal with invalid PID expression should return error.
    /// </summary>
    [Fact] // T:3157
    public void ProcessSignal_InvalidPid_ShouldReturnError()
    {
        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            return; // Skip on Windows

        var err = SignalHandler.ProcessSignal(ServerCommand.Stop, "not-a-pid");
        err.ShouldNotBeNull();
    }
}