/// <summary>
/// Initializes a new instance of the <see cref="ImageExplorerViewModel" /> class.
/// </summary>
/// <param name="imageCache">Cache which notifies about loaded or removed images.</param>
public ImageExplorerViewModel(IObservableCache <ImageHandle, string> imageCache)
{
Guard.Against.ArgumentNull(imageCache, nameof(imageCache));
var connection = imageCache.Connect();
SelectNext = ReactiveCommand.Create(SelectNextImpl);
SelectPrevious = ReactiveCommand.Create(SelectPreviousImpl);
_requestRemove = ReactiveCommand.Create <IImageExplorerItemViewModel, ImageHandle>(
vm => imageCache.Items.FirstOrDefault(x => x.LoadingSettings.FilePath == vm.ExplorerItem.FilePath),
outputScheduler: RxApp.TaskpoolScheduler);
DeletionRequests = _requestRemove.AsObservable();
Selections = this.WhenAnyValue(x => x.SelectedItem)
.DistinctUntilChanged()
.Select(vm => imageCache.Items.FirstOrDefault(x => x.LoadingSettings.FilePath == vm?.ExplorerItem.FilePath));
this.WhenActivated(d =>
{
connection
.ObserveOn(RxApp.TaskpoolScheduler)
.Filter(x => x?.Preview != null)
.Transform(x => new ImageExplorerItem(x.LoadingSettings.FilePath, x.OriginalImage.ToThumbnail(50)))
.DisposeMany()
.Transform(x => new ImageExplorerItemViewModel(x) as IImageExplorerItemViewModel)
.ObserveOn(RxApp.MainThreadScheduler)
.Bind(out _children)
.Subscribe(_ => SelectedItem ??= Children.FirstOrDefault())
.DisposeWith(d);
connection
.Where(x => x != null)
.Throttle(TimeSpan.FromMilliseconds(200))
.Select(_ => Children.Select(x => x.RequestRemove).Merge())
.Switch()
.InvokeCommand(_requestRemove)
.DisposeWith(d);
});
}
