livia-test/Livia/Models/IdleTimer.cs

using System.Windows.Threading;
using CommunityToolkit.Mvvm.Messaging;
using Livia.Models.Data;
using Livia.Properties;
using Livia.Utility;
using Livia.Views.Utility;
using Microsoft.Extensions.Logging;

namespace Livia.Models;

public interface IIdleTimer
{
    void ResetTimer();
}

public class IdleTimerTickMessage(IIdleTimer idleTimer)
{
    public readonly IIdleTimer IdleTimer = idleTimer;
}

public class IdleTimer : IIdleTimer
{
    private DateTime _lastActiveTime = DateTime.Now;
    private readonly TimeSpan _lockAfter = TimeSpan.FromMinutes(Settings.Default.LogoutAfter);
    private readonly ILogger _logger;
    private readonly IServerHandler _serverHandler;
    private readonly IWarningSystem _warningSystem;

    private static readonly TimeSpan TickInterval = new(0, 0, 5);
    private static readonly TimeSpan SnackBarWarningTime = new(0, 1, 0);

    public IdleTimer(ILogger logger, IServerHandler serverHandler, IWarningSystem warningSystem)
    {
        _logger = logger;
        _serverHandler = serverHandler;
        _warningSystem = warningSystem;

        if (Settings.Default.LogoutAfter <= 0) 
            return;

        DispatcherTimer dispatcherTimer = new();
        dispatcherTimer.Tick += Tick;
        dispatcherTimer.Interval = TickInterval;
        dispatcherTimer.Start();
    }

    private void Tick(object? sender, EventArgs? e)
    {
        //sent tick message, any busy module will reset timer when receives this message
        WeakReferenceMessenger.Default.Send(new IdleTimerTickMessage(this));

        //no access, do not lock again
        if (!_serverHandler.IsLoggedIn)
        {
            ResetTimer();
            return;
        }

        TimeSpan idleTime = DateTime.Now - _lastActiveTime;

        TimeSpan timeToLock = _lockAfter - idleTime;
        
        if (timeToLock <= TimeSpan.Zero)
        {
            _logger.LogInformation("Idle time up");
            _warningSystem.AddSnackbarMessage("IdleTimeout");
            ResetTimer();
            WeakReferenceMessenger.Default.Send(new LogoutMessage());

        }
        else if (timeToLock <= SnackBarWarningTime)
        {
            _warningSystem.AddSnackbarMessage(TickInterval - TimeSpan.FromSeconds(0.7), "IdleTimeoutWarning", (int)Math.Ceiling(timeToLock.TotalSeconds));
        }

        //waiting
    }

    public void ResetTimer()
    {
        //_logger.LogInformation("Timer reset");
        _lastActiveTime = DateTime.Now;
    }
}