ShellViewModel.cs

using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows.Input;
using System.Windows.Threading;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using MahApps.Metro.Controls;
using MahApps.Metro.Controls.Dialogs;
using Vereinsmeisterschaften.Contracts.Services;
using Vereinsmeisterschaften.Core.Contracts.Services;
using Vereinsmeisterschaften.Properties;
 
namespace Vereinsmeisterschaften.ViewModels;

public partial class ShellViewModel : ObservableObject
{
    public string CurrentWorkspaceFolder => _workspaceService.PersistentPath;

    public bool HasUnsavedChanges => _workspaceService.HasUnsavedChanges;

    [ObservableProperty]
    private bool _isWorkspaceFlyoutOpen;
 
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
    private readonly INavigationService _navigationService;
    private IDialogCoordinator _dialogCoordinator;
    private IWorkspaceService _workspaceService;
 
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
    #region Setting Keys
 
    private const string SETTING_KEY_LAST_WORKSPACE_PATHS = "LastWorkspacePaths";
    private const string SETTING_KEY_LAST_WORKSPACE_FOLDER = "LastWorkspaceFolder";
 
    #endregion
    
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
    #region Hamburger menu items

    [ObservableProperty]
    private HamburgerMenuItem _selectedMenuItem;

    [ObservableProperty]
    private HamburgerMenuItem _selectedOptionsMenuItem;

    public ObservableCollection<HamburgerMenuItem> MenuItems { get; } = new ObservableCollection<HamburgerMenuItem>()
    {
        new HamburgerMenuGlyphItem() { Label = Resources.ShellMainPage, Glyph = "\uE80F", TargetPageType = typeof(MainViewModel) },
        new HamburgerMenuGlyphItem() { Label = Resources.ShellWorkspacePage, Glyph = "\uE821", TargetPageType = typeof(WorkspaceViewModel) },
        new HamburgerMenuGlyphItem() { Label = Resources.ShellCompetitionPage, Glyph = "\uF0E3", TargetPageType = typeof(CompetitionViewModel) },
        new HamburgerMenuGlyphItem() { Label = Resources.ShellPeoplePage, Glyph = "\uE77B", TargetPageType = typeof(PeopleViewModel) },
        new HamburgerMenuGlyphItem() { Label = Resources.ShellPrepareRacesPage, Glyph = "\uE7C1", TargetPageType = typeof(PrepareRacesViewModel) },
        new HamburgerMenuGlyphItem() { Label = Resources.ShellTimeInputPage, Glyph = "\uE916", TargetPageType = typeof(TimeInputViewModel) },
        new HamburgerMenuGlyphItem() { Label = Resources.ShellResultsPage, Glyph = "\uE9F9", TargetPageType = typeof(ResultsViewModel) },
        new HamburgerMenuGlyphItem() { Label = Resources.ShellAnalyticsPage, Glyph = "\uE9D2", TargetPageType = typeof(AnalyticsViewModel) },
        new HamburgerMenuGlyphItem() { Label = Resources.ShellCreateDocumentsPage, Glyph = "\uE8A5", TargetPageType = typeof(CreateDocumentsViewModel) },
    };

    public ObservableCollection<HamburgerMenuItem> OptionMenuItems { get; } = new ObservableCollection<HamburgerMenuItem>()
    {
        new HamburgerMenuGlyphItem() { Label = Resources.ShellSettingsPage, Glyph = "\uE713", TargetPageType = typeof(SettingsViewModel) }
    };
 
    #endregion
 
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
    #region Commands
 
    private RelayCommand _goBackCommand;
    private ICommand _menuItemInvokedCommand;
    private ICommand _optionsMenuItemInvokedCommand;
    private ICommand _loadedCommand;
    private ICommand _unloadedCommand;
    private ICommand _closingCommand;
    private ICommand _saveWorkspaceCommand;
    private ICommand _openWorkspaceFlyoutCommand;

    public RelayCommand GoBackCommand => _goBackCommand ?? (_goBackCommand = new RelayCommand(() => _navigationService.GoBack(), () => _navigationService.CanGoBack));

    public ICommand MenuItemInvokedCommand => _menuItemInvokedCommand ?? (_menuItemInvokedCommand = new RelayCommand(() => NavigateTo(SelectedMenuItem.TargetPageType)));

    public ICommand OptionsMenuItemInvokedCommand => _optionsMenuItemInvokedCommand ?? (_optionsMenuItemInvokedCommand = new RelayCommand(() => NavigateTo(SelectedOptionsMenuItem.TargetPageType)));

    public ICommand LoadedCommand => _loadedCommand ?? (_loadedCommand = new RelayCommand(OnLoaded));

    public ICommand UnloadedCommand => _unloadedCommand ?? (_unloadedCommand = new RelayCommand(OnUnloaded));

    public ICommand ClosingCommand => _closingCommand ?? (_closingCommand = new RelayCommand<CancelEventArgs>(OnClosing));

    public ICommand SaveWorkspaceCommand => _saveWorkspaceCommand ?? (_saveWorkspaceCommand = new RelayCommand(async () => await _workspaceService?.Save(CancellationToken.None)));

    public ICommand OpenWorkspaceFlyoutCommand => _openWorkspaceFlyoutCommand ?? (_openWorkspaceFlyoutCommand = new RelayCommand(() => IsWorkspaceFlyoutOpen = !IsWorkspaceFlyoutOpen));
 
    #endregion
 
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    public ShellViewModel(INavigationService navigationService, IDialogCoordinator dialogCoordinator, IWorkspaceService workspaceService)
    {
        _navigationService = navigationService;
        _dialogCoordinator = dialogCoordinator;
        _workspaceService = workspaceService;
    }
 
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
    #region Load and unload
 
    private async void OnLoaded()
    {
        _navigationService.Navigated += OnNavigated;
        _workspaceService.PropertyChanged += _workspaceService_PropertyChanged;
        updateMenuItemsEnabledState();
 
        object lastWorkspacePaths = App.Current.Properties[SETTING_KEY_LAST_WORKSPACE_PATHS];
        if (lastWorkspacePaths != null)
        {
            Newtonsoft.Json.Linq.JArray lastWorkspacePathsJArray = lastWorkspacePaths as Newtonsoft.Json.Linq.JArray;
            List<string> lastWorkspacePathsList = lastWorkspacePathsJArray.ToObject<List<string>>();
            _workspaceService.LastWorkspacePaths = new ObservableCollection<string>(lastWorkspacePathsList);
        }
 
        // Load the workspace
        try
        {
            await _workspaceService.Load(App.Current.Properties[SETTING_KEY_LAST_WORKSPACE_FOLDER]?.ToString(), CancellationToken.None);
        }
        catch (Exception ex)
        {
            await _dialogCoordinator.ShowMessageAsync(this, Resources.ErrorString, ex.Message);
        }
    }
 
    private void OnUnloaded()
    {
        _navigationService.Navigated -= OnNavigated;
        _workspaceService.PropertyChanged -= _workspaceService_PropertyChanged;
    }
 
    private void _workspaceService_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
    {
        switch (e.PropertyName)
        {
            case nameof(IWorkspaceService.HasUnsavedChanges): OnPropertyChanged(nameof(HasUnsavedChanges)); break;
            case nameof(IWorkspaceService.PersistentPath): OnPropertyChanged(nameof(CurrentWorkspaceFolder)); break;
            case nameof(IWorkspaceService.IsWorkspaceOpen):
                {
                    OnPropertyChanged(nameof(CurrentWorkspaceFolder));
                    updateMenuItemsEnabledState();
                    break;
                }
            default: break;
        }
    }

    private void updateMenuItemsEnabledState()
    {
        foreach (HamburgerMenuItem menuItem in MenuItems)
        {
            if (menuItem.TargetPageType == typeof(MainViewModel) || menuItem.TargetPageType == typeof(WorkspaceViewModel)) { continue; }
 
            menuItem.IsEnabled = _workspaceService.IsWorkspaceOpen;
        }
    }
 
    #endregion
 
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
    #region Closing
 
    // Close behaviour: https://github.com/MahApps/MahApps.Metro/issues/3535
    private bool _forceClose = false;

    public event EventHandler WindowCloseRequested;
    protected void OnClosing(CancelEventArgs e)
    {
        // force method to abort - we'll force a close explicitly
        e.Cancel = true;
 
        if (_forceClose)
        {
            // cleanup code already ran
            e.Cancel = false;
            return;
        }
 
        // execute shutdown logic - set ForceClose and request Close() to actually close the window
        Dispatcher.CurrentDispatcher.InvokeAsync(async () =>
        {
            bool save = false, cancel = false;
            (save, cancel) = await CheckForUnsavedChangesAndQueryUserAction();
            if (!cancel)
            {
                if (save)
                {
                    try
                    {
                        await _workspaceService.Save(CancellationToken.None);
                    }
                    catch (Exception ex)
                    {
                        await _dialogCoordinator.ShowMessageAsync(this, Resources.ErrorString, ex.Message);
                    }
                }
                App.Current.Properties[SETTING_KEY_LAST_WORKSPACE_FOLDER] = CurrentWorkspaceFolder;
                App.Current.Properties[SETTING_KEY_LAST_WORKSPACE_PATHS] = _workspaceService.LastWorkspacePaths.ToList();
                _forceClose = true;
                WindowCloseRequested?.Invoke(this, null);   // Notify the ShellWindow to close
            }
        }, DispatcherPriority.Normal);
    }

    public async Task<(bool saveOut, bool cancelOut)> CheckForUnsavedChangesAndQueryUserAction()
    {
        bool save = false, cancel = false;
        if (_workspaceService?.HasUnsavedChanges ?? false)
        {
            MetroDialogSettings dialogButtonSettings = new MetroDialogSettings()
            {
                AffirmativeButtonText = Resources.SaveString,
                NegativeButtonText = Resources.DontSaveString,
                FirstAuxiliaryButtonText = Resources.CancelString,
                DefaultButtonFocus = MessageDialogResult.Affirmative
            };
            MessageDialogResult dialogResult = await _dialogCoordinator.ShowMessageAsync(this, Resources.UnsavedChangesString, Resources.UnsavedChangesSavePromptString,
                                                                                        MessageDialogStyle.AffirmativeAndNegativeAndSingleAuxiliary, dialogButtonSettings);
            switch (dialogResult)
            {
                case MessageDialogResult.Affirmative: save = true; cancel = false; break;
                case MessageDialogResult.Negative: save = false; cancel = false; break;
                case MessageDialogResult.FirstAuxiliary: save = false; cancel = true; break;
                default: break;
            }
        }
        return (save, cancel);
    }
 
    #endregion
 
    // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 
    private void NavigateTo(Type targetViewModel)
    {
        if (targetViewModel != null)
        {
            _navigationService.NavigateTo(targetViewModel.FullName);
        }
    }
 
    private void OnNavigated(object sender, string viewModelName)
    {
        var item = MenuItems.OfType<HamburgerMenuItem>().FirstOrDefault(i => viewModelName == i.TargetPageType?.FullName);
        if (item != null)
        {
            SelectedMenuItem = item;
        }
        else
        {
            SelectedOptionsMenuItem = OptionMenuItems.OfType<HamburgerMenuItem>().FirstOrDefault(i => viewModelName == i.TargetPageType?.FullName);
        }
        GoBackCommand.NotifyCanExecuteChanged();
    }
}