sa/Stars Assistant/ViewModels/BuColViewModel.cs

using System.Collections.ObjectModel;
using System.Reactive.Disposables;
using System.Reactive.Linq;
using DynamicData;
using ReactiveUI;
using ReactiveUI.SourceGenerators;
using Splat;
using StarsAssistant.Model;
using StarsAssistant.Services;

namespace StarsAssistant.ViewModels;

public partial class BuColViewModel : ViewModelBase
{
    private readonly ReadOnlyObservableCollection<PlayerPlanetViewModel> _playerPlanetsView;
    public ReadOnlyObservableCollection<PlayerPlanetViewModel> PlayerPlanets => _playerPlanetsView;

    [Reactive]
    private PlayerPlanetViewModel? _selectedPlanet;

    private string? _lastSelectedPlanetName;
    
    public BuColViewModel()
    {
        var planetManager = Locator.Current.GetService<PlanetManager>()!;

        planetManager.PlayerPlanetsSource
            .ObserveOn(RxApp.MainThreadScheduler)
            .Bind(out _playerPlanetsView)
            .DisposeMany()
            .Subscribe();

        this.WhenAnyValue(x => x.SelectedPlanet)
            .Subscribe(planet => _lastSelectedPlanetName = planet?.Name);
        
        this.WhenActivated((CompositeDisposable disposables) => 
        {
            planetManager.PlanetsReloaded
                .ObserveOn(RxApp.MainThreadScheduler)
                .Subscribe(_ => RestoreSelection())
                .DisposeWith(disposables);
        });
    }

    private void RestoreSelection()
    {
        if (_lastSelectedPlanetName != null)
        {
            SelectedPlanet = PlayerPlanets.FirstOrDefault(p => p.Name == _lastSelectedPlanetName);
        }
    }
}