teamsiso/src/TeamsISO.App/ViewModels/ToastViewModel.cs

using System.Windows.Input;
using System.Windows.Threading;

namespace TeamsISO.App.ViewModels;

/// <summary>
/// Lightweight transient-notification view-model. The main view holds a single
/// instance bound to a small overlay at the bottom of the content area.
/// <see cref="Show"/> displays a message for a fixed duration before auto-hiding;
/// successive Show calls reset the timer instead of stacking, so the user always
/// sees the most recent action's feedback.
/// </summary>
public sealed class ToastViewModel : ObservableObject
{
    private readonly DispatcherTimer _hideTimer;
    private string _message = string.Empty;
    private bool _isVisible;
    private string _accent = "Wd.Accent.Cyan";

    public ToastViewModel(Dispatcher dispatcher)
    {
        _hideTimer = new DispatcherTimer(DispatcherPriority.Background, dispatcher)
        {
            Interval = TimeSpan.FromSeconds(3),
        };
        _hideTimer.Tick += (_, _) =>
        {
            _hideTimer.Stop();
            IsVisible = false;
        };
        DismissCommand = new RelayCommand(Hide);
    }

    /// <summary>
    /// Manual dismiss. Stops the auto-hide timer and hides the toast
    /// immediately. Bound to the X close button on the toast overlay so an
    /// operator running a live show can clear visual clutter without waiting
    /// 3 seconds.
    /// </summary>
    public ICommand DismissCommand { get; }

    private void Hide()
    {
        _hideTimer.Stop();
        IsVisible = false;
    }

    public string Message
    {
        get => _message;
        private set => SetField(ref _message, value);
    }

    public bool IsVisible
    {
        get => _isVisible;
        private set => SetField(ref _isVisible, value);
    }

    /// <summary>
    /// Brush resource key for the accent dot. "Wd.Accent.Cyan" for success-style
    /// (default), "Wd.Accent.Coral" for warnings.
    /// </summary>
    public string Accent
    {
        get => _accent;
        private set => SetField(ref _accent, value);
    }

    /// <summary>Show a success-style toast for ~3 seconds.</summary>
    public void Show(string message) => ShowImpl(message, "Wd.Accent.Cyan");

    /// <summary>Show a warning-style toast (coral accent) for ~3 seconds.</summary>
    public void Warn(string message) => ShowImpl(message, "Wd.Accent.Coral");

    private void ShowImpl(string message, string accentKey)
    {
        Message = message;
        Accent = accentKey;
        IsVisible = true;
        _hideTimer.Stop();
        _hideTimer.Start();
    }
}