SelectLanguagePopupViewModel.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using CommunityToolkit.Mvvm.Messaging;
using Microsoft.Maui.Storage;
using NeuroAccessMaui.Resources.Languages;
using NeuroAccessMaui.Services;
using NeuroAccessMaui.Services.Localization;
 
namespace NeuroAccessMaui.UI.Popups.Settings
{
    public partial class SelectLanguagePopupViewModel : BasePopupViewModel
    {
        // Expose the supported languages.
        public ObservableCollection<ObservableLanguage> Languages { get; }
 
        [ObservableProperty]
        private string? selectedLanguageName;
 
        public SelectLanguagePopupViewModel()
        {
            this.SelectedLanguageName = App.SelectedLanguage.Name;
 
            this.Languages = new ObservableCollection<ObservableLanguage>(
                App.SupportedLanguages.Select(l =>
                    new ObservableLanguage(l, this.SelectLanguageAsync)
                    {
                        IsSelected = l.Name == this.SelectedLanguageName
                    }));
 
 
        }
 
 
        public override Task OnAppearingAsync()
        {
            if(this.SelectedLanguageName is not null)
                WeakReferenceMessenger.Default.Send(new ScrollToLanguageMessage(this.SelectedLanguageName));
 
            return base.OnAppearingAsync();
        }
 
        [RelayCommand(AllowConcurrentExecutions = false)]
        public async Task SelectLanguageAsync(string languageName)
        {
            // Find the language that matches the selection.
            LanguageInfo? SelectedLanguage = this.Languages.FirstOrDefault(l => l.Language.Name == languageName)?.Language;
            if (SelectedLanguage is null)
                return;
 
            // Update selection flags for visual feedback.
            foreach (ObservableLanguage Observable in this.Languages)
            {
                bool IsSelected = Observable.Language.Name == languageName;
                if (Observable.IsSelected != IsSelected)
                    Observable.IsSelected = IsSelected;
            }
 
            // Update selected language property.
            this.SelectedLanguageName = SelectedLanguage.Name;
 
            // Update the language if a new language is selected.
            if (SelectedLanguage.Name != CultureInfo.CurrentCulture.Name)
            {
                Preferences.Set("user_selected_language", SelectedLanguage.TwoLetterISOLanguageName);
                LocalizationManager.Current.CurrentCulture = SelectedLanguage;
            }
 
            // Display an alert that the language has been changed. And app should be restarted to make sure the changes are applied properly
            await ServiceRef.UiService.DisplayAlert(
                ServiceRef.Localizer[nameof(AppResources.LanguageChangedTitle)],
                ServiceRef.Localizer[nameof(AppResources.LanguageChangedMessage)],
                ServiceRef.Localizer[nameof(AppResources.Ok)]
            );
 
            // Dismiss the popup via the UI service.
            await ServiceRef.PopupService.PopAsync();
        }
    }
}