Aaru/Aaru.Gui/ViewModels/MainWindowViewModel.cs

using System.Linq;
using System.Reactive;
using Aaru.Database;
using Aaru.Gui.Views;
using Avalonia;
using Avalonia.Controls;
using Avalonia.Controls.ApplicationLifetimes;
using MessageBox.Avalonia;
using ReactiveUI;

namespace Aaru.Gui.ViewModels
{
    public class MainWindowViewModel : ViewModelBase
    {
        readonly MainWindow _view;

        public MainWindowViewModel(MainWindow view)
        {
            AboutCommand      = ReactiveCommand.Create(ExecuteAboutCommand);
            EncodingsCommand  = ReactiveCommand.Create(ExecuteEncodingsCommand);
            PluginsCommand    = ReactiveCommand.Create(ExecutePluginsCommand);
            StatisticsCommand = ReactiveCommand.Create(ExecuteStatisticsCommand);
            ExitCommand = ReactiveCommand.Create(ExecuteExitCommand);
            _view             = view;
        }

        public string Greeting => "Welcome to Aaru!";

        public bool NativeMenuNotSupported =>
            !NativeMenu.GetIsNativeMenuExported((Application.Current.ApplicationLifetime as
                                                     IClassicDesktopStyleApplicationLifetime)?.MainWindow);

        public ReactiveCommand<Unit, Unit> AboutCommand      { get; }
        public ReactiveCommand<Unit, Unit> EncodingsCommand  { get; }
        public ReactiveCommand<Unit, Unit> PluginsCommand    { get; }
        public ReactiveCommand<Unit, Unit> StatisticsCommand { get; }
        public ReactiveCommand<Unit, Unit> ExitCommand { get; }

        internal void ExecuteAboutCommand()
        {
            var dialog = new AboutDialog();
            dialog.DataContext = new AboutDialogViewModel(dialog);
            dialog.ShowDialog(_view);
        }

        internal void ExecuteEncodingsCommand()
        {
            var dialog = new EncodingsDialog();
            dialog.DataContext = new EncodingsDialogViewModel(dialog);
            dialog.ShowDialog(_view);
        }

        internal void ExecutePluginsCommand()
        {
            var dialog = new PluginsDialog();
            dialog.DataContext = new PluginsDialogViewModel(dialog);
            dialog.ShowDialog(_view);
        }

        internal void ExecuteStatisticsCommand()
        {
            using var ctx = AaruContext.Create(Settings.Settings.LocalDbPath);

            if(!ctx.Commands.Any()     &&
               !ctx.Filesystems.Any()  &&
               !ctx.Filters.Any()      &&
               !ctx.MediaFormats.Any() &&
               !ctx.Medias.Any()       &&
               !ctx.Partitions.Any()   &&
               !ctx.SeenDevices.Any())
            {
                MessageBoxManager.GetMessageBoxStandardWindow("Warning", "There are no statistics.").ShowDialog(_view);

                return;
            }

            var dialog = new StatisticsDialog();
            dialog.DataContext = new StatisticsDialogViewModel(dialog);
            dialog.ShowDialog(_view);
        }

        internal void ExecuteExitCommand() => (Application.Current.ApplicationLifetime as ClassicDesktopStyleApplicationLifetime)?.Shutdown();
    }
}