gamenight/FrontendAvalonia/FrontendAvalonia/ViewModels/MainViewModel.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Reactive;
using System.Threading.Tasks;
using System.Windows.Input;
using Avalonia.Controls;
using Avalonia.Input;
using DynamicData.Binding;
using FrontendAvalonia.Models;
using FrontendAvalonia.Services.GamenightApi;
using ReactiveUI;

namespace FrontendAvalonia.ViewModels;

public class MainViewModel : PageViewModelBase
{
    private GamenightModel GamenightModel { get; }

    private List<MenuItemViewModel> _MenuItems = new();

    public List<MenuItemViewModel> MenuItems
    {
        get => _MenuItems;
        set => this.RaiseAndSetIfChanged(ref _MenuItems, value);
    }

    public IGamenight? Gamenight { get; }

    private LoginViewModel LoginViewModel { get; }

    private GamenightsViewModel GamenightsViewModel { get; }

    public MainViewModel(IScreen screen, GamenightModel gamenightModel, IGamenight gamenight, LoginViewModel loginViewModel, GamenightsViewModel gamenightsViewModel)
    :base(screen)
    {
        GamenightModel = gamenightModel;
        MenuItems = new List<MenuItemViewModel>();
        Gamenight = gamenight;
        LoginViewModel = loginViewModel;
        GamenightsViewModel = gamenightsViewModel;

        gamenightModel.WhenAnyValue(m => m.UserToken).Subscribe(CreateMenuItems);
    }

    private Task NavigateToLoginPage()
    {
        return Task.FromResult(HostScreen.Router.Navigate.Execute(LoginViewModel));
    }

    private Task NavigateToGamenightsPage()
    {
        return Task.FromResult(HostScreen.Router.NavigateAndReset.Execute(GamenightsViewModel));
    }

    private void CreateMenuItems(string? userToken)
    {
        if (userToken != null)
        {
            MenuItems = new List<MenuItemViewModel>
            {
                new()
                {
                    Header = "_Logout",
                    Command = ReactiveCommand.Create(async () =>
                    {
                        GamenightModel.UserToken = null;
                        await NavigateToGamenightsPage();
                    }),
                    CommandParameter = null!,
                    Items = new List<MenuItemViewModel>(),
                }
            };
        }
        else
        {
            MenuItems = new List<MenuItemViewModel>
            {
                new()
                {
                    Header = "_Login",
                    Command = ReactiveCommand.CreateFromTask(NavigateToLoginPage),
                    CommandParameter = null!,
                    Items = new List<MenuItemViewModel>(),
                }
            };
        }
    }

    // The command that navigates a user back.
    public ReactiveCommand<Unit, IRoutableViewModel?> GoBack => HostScreen.Router.NavigateBack;
}