Fix rmcrackan/Libation#511

Source/LibationAvalonia/ViewModels/GridEntry.cs

@@ -35,18 +35,29 @@ namespace LibationAvalonia.ViewModels
 		#region Model properties exposed to the view
 
 		private Avalonia.Media.Imaging.Bitmap _cover;
-		public Avalonia.Media.Imaging.Bitmap Cover { get => _cover; protected set { this.RaiseAndSetIfChanged(ref _cover, value); } }
+		private string _purchasedate;
-		public string PurchaseDate { get; protected set; }
+		private string _series;
-		public string Series { get; protected set; }
+		private string _title;
-		public string Title { get; protected set; }
+		private string _length;
-		public string Length { get; protected set; }
+		private string _authors;
-		public string Authors { get; protected set; }
+		private string _narrators;
-		public string Narrators { get; protected set; }
+		private string _category;
-		public string Category { get; protected set; }
+		private string _misc;
-		public string Misc { get; protected set; }
+		private string _description;
-		public string Description { get; protected set; }
+		private Rating _productrating;
-		public Rating ProductRating { get; protected set; }
 		protected Rating _myRating;
+
+		public Avalonia.Media.Imaging.Bitmap Cover { get => _cover; protected set => this.RaiseAndSetIfChanged(ref _cover, value); }
+		public string PurchaseDate { get => _purchasedate; protected set => this.RaiseAndSetIfChanged(ref _purchasedate, value); }
+		public string Series { get => _series; protected set => this.RaiseAndSetIfChanged(ref _series, value); }
+		public string Title { get => _title; protected set => this.RaiseAndSetIfChanged(ref _title, value); }
+		public string Length { get => _length; protected set => this.RaiseAndSetIfChanged(ref _length, value); }
+		public string Authors { get => _authors; protected set => this.RaiseAndSetIfChanged(ref _authors, value); }
+		public string Narrators { get => _narrators; protected set => this.RaiseAndSetIfChanged(ref _narrators, value); }
+		public string Category { get => _category; protected set => this.RaiseAndSetIfChanged(ref _category, value); }
+		public string Misc { get => _misc; protected set => this.RaiseAndSetIfChanged(ref _misc, value); }
+		public string Description { get => _description; protected set => this.RaiseAndSetIfChanged(ref _description, value); }
+		public Rating ProductRating { get => _productrating; protected set => this.RaiseAndSetIfChanged(ref _productrating, value); }
 		public Rating MyRating
 		{
 			get => _myRating;

Source/LibationAvalonia/ViewModels/LibraryBookEntry.cs

@@ -58,8 +58,22 @@ namespace LibationAvalonia.ViewModels
 
 		public LibraryBookEntry(LibraryBook libraryBook)
 		{
-			LibraryBook = libraryBook;
+			setLibraryBook(libraryBook);
 			LoadCover();
+		}
+
+		public void UpdateLibraryBook(LibraryBook libraryBook)
+		{
+			if (AudibleProductId != libraryBook.Book.AudibleProductId)
+				throw new Exception("Invalid grid entry update. IDs must match");
+
+			UserDefinedItem.ItemChanged -= UserDefinedItem_ItemChanged;
+			setLibraryBook(libraryBook);
+		}
+
+		private void setLibraryBook(LibraryBook libraryBook)
+		{
+			LibraryBook = libraryBook;
 
 			Title = Book.Title;
 			Series = Book.SeriesNames();
@@ -77,6 +91,7 @@ namespace LibationAvalonia.ViewModels
 			Description = TrimTextToWord(LongDescription, 62);
 			SeriesIndex = Book.SeriesLink.FirstOrDefault()?.Index ?? 0;
 
+			this.RaisePropertyChanged(nameof(MyRating));
 			UserDefinedItem.ItemChanged += UserDefinedItem_ItemChanged;
 		}
 

Source/LibationAvalonia/ViewModels/ProductsDisplayViewModel.cs

@@ -20,11 +20,11 @@ namespace LibationAvalonia.ViewModels
 		public event EventHandler<int> RemovableCountChanged;
 
 		/// <summary>Backing list of all grid entries</summary>
-		private readonly List<GridEntry> SOURCE = new();
+		private readonly AvaloniaList<GridEntry> SOURCE = new();
 		/// <summary>Grid entries included in the filter set. If null, all grid entries are shown</summary>
 		private List<GridEntry> FilteredInGridEntries;
 		public string FilterString { get; private set; }
-		public DataGridCollectionView GridEntries { get; }
+		public DataGridCollectionView GridEntries { get; private set; }
 
 		private bool _removeColumnVisivle;
 		public bool RemoveColumnVisivle { get => _removeColumnVisivle; private set => this.RaiseAndSetIfChanged(ref _removeColumnVisivle, value); }
@@ -42,59 +42,60 @@ namespace LibationAvalonia.ViewModels
 		public ProductsDisplayViewModel()
 		{
 			SearchEngineCommands.SearchEngineUpdated += SearchEngineCommands_SearchEngineUpdated;
-			GridEntries = new(SOURCE);
+			VisibleCountChanged?.Invoke(this, 0);
-			GridEntries.Filter = CollectionFilter;
+		}
 
-			GridEntries.CollectionChanged += (s, e)
+		private static readonly System.Reflection.MethodInfo SetFlagsMethod;
-				=> VisibleCountChanged?.Invoke(this, GridEntries.OfType<LibraryBookEntry>().Count());
+
+		/// <summary>
+		/// Tells the <see cref="DataGridCollectionView"/> whether it should process changes to the underlying collection
+		/// </summary>
+		/// <remarks> DataGridCollectionView.CollectionViewFlags.ShouldProcessCollectionChanged = 4</remarks>
+		private void SetShouldProcessCollectionChanged(bool flagSet)
+			=> SetFlagsMethod.Invoke(GridEntries, new object[] { 4, flagSet });
+
+		static ProductsDisplayViewModel()
+		{
+			/*
+			 * When a book is removed from the library, SearchEngineUpdated is fired before LibrarySizeChanged, so
+			 * the book is removed from the filtered set and the grid is refreshed before RemoveBooks() is ever
+			 * called.
+			 * 
+			 * To remove an item from DataGridCollectionView, it must be be in the current filtered view. If it's
+			 * not and you try to remove the book from the source list, the source will fire NotifyCollectionChanged
+			 * on an invalid item and the DataGridCollectionView will throw an exception. There are two ways to
+			 * remove an item that is filtered out of the DataGridCollectionView:
+			 * 
+			 * (1)  Re-add the item to the filtered-in list and refresh the grid so DataGridCollectionView knows
+			 *		that the item is present. This causes the whole grid to flicker to refresh twice in rapid
+			 *		succession, which is undesirable.
+			 *		
+			 * (2)  Remove it from the underlying collection and suppress NotifyCollectionChanged. This is the
+			 *		method used. Steps to complete a removal using this method:
+			 *		
+			 *		(a)	Set DataGridCollectionView.CollectionViewFlags.ShouldProcessCollectionChanged to false.
+			 *		(b) Remove the item from the source list. The source will fire NotifyCollectionChanged, but the
+			 *			DataGridCollectionView will ignore it.
+			 *		(c) Reset the flag to true.
+			 */
+
+			SetFlagsMethod =
+				typeof(DataGridCollectionView)
+				.GetMethod("SetFlag", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
 		}
 
 		#region Display Functions
 
-		/// <summary>
+		internal void BindToGrid(List<LibraryBook> dbBooks)
-		/// Call when there's been a change to the library
-		/// </summary>
-		public async Task DisplayBooksAsync(List<LibraryBook> dbBooks)
 		{
-			try
+			GridEntries = new(SOURCE)
 			{
-				var existingSeriesEntries = SOURCE.SeriesEntries().ToList();
+				Filter = CollectionFilter
+			};
 
-				FilteredInGridEntries?.Clear();
+			GridEntries.CollectionChanged += (_, _)
-				SOURCE.Clear();
+				=> VisibleCountChanged?.Invoke(this, GridEntries.OfType<LibraryBookEntry>().Count());
-				SOURCE.AddRange(CreateGridEntries(dbBooks));
 
-				//If replacing the list, preserve user's existing collapse/expand
-				//state. When resetting a list, default state is cosed.
-				foreach (var series in existingSeriesEntries)
-				{
-					var sEntry = SOURCE.FirstOrDefault(ge => ge.AudibleProductId == series.AudibleProductId);
-					if (sEntry is SeriesEntry se)
-						se.Liberate.Expanded = series.Liberate.Expanded;
-				}
-
-				//Run query on new list
-				FilteredInGridEntries = QueryResults(SOURCE, FilterString);
-
-				await refreshGrid();
-
-			}
-			catch (Exception ex)
-			{
-				Serilog.Log.Error(ex, "Error displaying library in {0}", nameof(ProductsDisplayViewModel));
-			}
-		}
-
-		private async Task refreshGrid()
-		{
-			if (GridEntries.IsEditingItem)
-				await Dispatcher.UIThread.InvokeAsync(GridEntries.CommitEdit);
-
-			await Dispatcher.UIThread.InvokeAsync(GridEntries.Refresh);
-		}
-
-		private static List<GridEntry> CreateGridEntries(IEnumerable<LibraryBook> dbBooks)
-		{
 			var geList = dbBooks
 				.Where(lb => lb.Book.IsProduct())
 				.Select(b => new LibraryBookEntry(b))
@@ -103,26 +104,159 @@ namespace LibationAvalonia.ViewModels
 
 			var episodes = dbBooks.Where(lb => lb.Book.IsEpisodeChild());
 
-			foreach (var parent in dbBooks.Where(lb => lb.Book.IsEpisodeParent()))
+			var seriesBooks = dbBooks.Where(lb => lb.Book.IsEpisodeParent()).ToList();
+
+			foreach (var parent in seriesBooks)
 			{
 				var seriesEpisodes = episodes.FindChildren(parent);
 
 				if (!seriesEpisodes.Any()) continue;
 
 				var seriesEntry = new SeriesEntry(parent, seriesEpisodes);
+				seriesEntry.Liberate.Expanded = false;
 
 				geList.Add(seriesEntry);
 				geList.AddRange(seriesEntry.Children);
 			}
 
-			var bookList =  geList.OrderByDescending(e => e.DateAdded).ToList();
+			//Create the filtered-in list before adding entries to avoid a refresh
+			FilteredInGridEntries = QueryResults(geList, FilterString);
+			SOURCE.AddRange(geList.OrderByDescending(e => e.DateAdded));
+		}
 
-			//ListIndex is used by RowComparer to make column sort stable
+		/// <summary>
-			int index = 0;
+		/// Call when there's been a change to the library
-			foreach (GridEntry di in bookList)
+		/// </summary>
-				di.ListIndex = index++;
+		internal async Task UpdateGridAsync(List<LibraryBook> dbBooks)
+		{
+			#region Add new or update existing grid entries
 
-			return bookList;
+			//Add absent entries to grid, or update existing entry
+			var allEntries = SOURCE.BookEntries();
+			var seriesEntries = SOURCE.SeriesEntries().ToList();
+			var parentedEpisodes = dbBooks.ParentedEpisodes();
+
+			await Dispatcher.UIThread.InvokeAsync(() =>
+			{
+				foreach (var libraryBook in dbBooks.OrderBy(e => e.DateAdded))
+				{
+					var existingEntry = allEntries.FindByAsin(libraryBook.Book.AudibleProductId);
+
+					if (libraryBook.Book.IsProduct())
+						UpsertBook(libraryBook, existingEntry);
+					else if (parentedEpisodes.Any(lb => lb == libraryBook))
+						//Only try to add or update is this LibraryBook is a know child of a parent
+						UpsertEpisode(libraryBook, existingEntry, seriesEntries, dbBooks);
+				}
+			});
+
+			#endregion
+
+			#region Remove entries no longer in the library
+
+			//Rapid successive book removals will cause changes to SOURCE after the update has
+			//begun but before it has completed, so perform all updates on a copy of the list.
+			var sourceSnapshot = SOURCE.ToList();
+
+			// remove deleted from grid.
+			// note: actual deletion from db must still occur via the RemoveBook feature. deleting from audible will not trigger this
+			var removedBooks =
+				sourceSnapshot
+				.BookEntries()
+				.ExceptBy(dbBooks.Select(lb => lb.Book.AudibleProductId), ge => ge.AudibleProductId);
+
+			//Remove books in series from their parents' Children list
+			foreach (var removed in removedBooks.Where(b => b.Parent is not null))
+				removed.Parent.RemoveChild(removed);
+
+			//Remove series that have no children
+			var removedSeries = sourceSnapshot.EmptySeries();
+
+			await Dispatcher.UIThread.InvokeAsync(() => RemoveBooks(removedBooks, removedSeries));
+
+			#endregion
+
+			await Filter(FilterString);
+			GC.Collect(GC.MaxGeneration, GCCollectionMode.Aggressive, true, true);
+		}
+
+		private void RemoveBooks(IEnumerable<LibraryBookEntry> removedBooks, IEnumerable<SeriesEntry> removedSeries)
+		{
+			foreach (var removed in removedBooks.Cast<GridEntry>().Concat(removedSeries).Where(b => b is not null).ToList())
+			{
+				if (GridEntries.PassesFilter(removed))
+					GridEntries.Remove(removed);
+				else
+				{
+					SetShouldProcessCollectionChanged(false);
+					SOURCE.Remove(removed);
+					SetShouldProcessCollectionChanged(true);
+				}
+			}
+		}
+
+		private void UpsertBook(LibraryBook book, LibraryBookEntry existingBookEntry)
+		{
+			if (existingBookEntry is null)
+				// Add the new product to top
+				SOURCE.Insert(0, new LibraryBookEntry(book));
+			else
+				// update existing
+				existingBookEntry.UpdateLibraryBook(book);
+		}
+
+		private void UpsertEpisode(LibraryBook episodeBook, LibraryBookEntry existingEpisodeEntry, List<SeriesEntry> seriesEntries, IEnumerable<LibraryBook> dbBooks)
+		{
+			if (existingEpisodeEntry is null)
+			{
+				LibraryBookEntry episodeEntry;
+
+				var seriesEntry = seriesEntries.FindSeriesParent(episodeBook);
+
+				if (seriesEntry is null)
+				{
+					//Series doesn't exist yet, so create and add it
+					var seriesBook = dbBooks.FindSeriesParent(episodeBook);
+
+					if (seriesBook is null)
+					{
+						//This is only possible if the user's db  has some malformed
+						//entries from earlier Libation releases that could not be
+						//automatically fixed. Log, but don't throw.
+						Serilog.Log.Logger.Error("Episode={0}, Episode Series: {1}", episodeBook, episodeBook.Book.SeriesNames());
+						return;
+					}
+
+					seriesEntry = new SeriesEntry(seriesBook, new[] { episodeBook });
+					seriesEntries.Add(seriesEntry);
+
+					episodeEntry = seriesEntry.Children[0];
+					seriesEntry.Liberate.Expanded = true;
+					SOURCE.Insert(0, seriesEntry);
+				}
+				else
+				{
+					//Series exists. Create and add episode child then update the SeriesEntry
+					episodeEntry = new(episodeBook) { Parent = seriesEntry };
+					seriesEntry.Children.Add(episodeEntry);
+					var seriesBook = dbBooks.Single(lb => lb.Book.AudibleProductId == seriesEntry.LibraryBook.Book.AudibleProductId);
+					seriesEntry.UpdateLibraryBook(seriesBook);
+				}
+
+				//Add episode to the grid beneath the parent
+				int seriesIndex = SOURCE.IndexOf(seriesEntry);
+				SOURCE.Insert(seriesIndex + 1, episodeEntry);
+			}
+			else
+				existingEpisodeEntry.UpdateLibraryBook(episodeBook);
+		}
+
+		private async Task refreshGrid()
+		{
+			if (GridEntries.IsEditingItem)
+				await Dispatcher.UIThread.InvokeAsync(GridEntries.CommitEdit);
+
+			await Dispatcher.UIThread.InvokeAsync(GridEntries.Refresh);
 		}
 
 		public async Task ToggleSeriesExpanded(SeriesEntry seriesEntry)
@@ -138,9 +272,6 @@ namespace LibationAvalonia.ViewModels
 
 		public async Task Filter(string searchString)
 		{
-			if (searchString == FilterString)
-				return;
-
 			FilterString = searchString;
 
 			if (SOURCE.Count == 0)

Source/LibationAvalonia/ViewModels/QueryExtensions.cs

@@ -14,6 +14,12 @@ namespace LibationAvalonia.ViewModels
 		public static IEnumerable<SeriesEntry> SeriesEntries(this IEnumerable<GridEntry> gridEntries)
 			=> gridEntries.OfType<SeriesEntry>();
 
+		public static T? FindByAsin<T>(this IEnumerable<T> gridEntries, string audibleProductID) where T : GridEntry
+			=> gridEntries.FirstOrDefault(i => i.AudibleProductId == audibleProductID);
+
+		public static IEnumerable<SeriesEntry> EmptySeries(this IEnumerable<GridEntry> gridEntries)
+			=> gridEntries.SeriesEntries().Where(i => i.Children.Count == 0);
+
 		public static SeriesEntry? FindSeriesParent(this IEnumerable<GridEntry> gridEntries, LibraryBook seriesEpisode)
 		{
 			if (seriesEpisode.Book.SeriesLink is null) return null;

Source/LibationAvalonia/ViewModels/SeriesEntry.cs

@@ -56,15 +56,36 @@ namespace LibationAvalonia.ViewModels
 		{
 			Liberate = new LiberateButtonStatus(IsSeries);
 			SeriesIndex = -1;
-			LibraryBook = parent;
-
-			LoadCover();
 
 			Children = children
 				.Select(c => new LibraryBookEntry(c) { Parent = this })
 				.OrderBy(c => c.SeriesIndex)
 				.ToList();
 
+			setLibraryBook(parent);
+			LoadCover();
+		}
+
+		public void RemoveChild(LibraryBookEntry lbe)
+		{
+			Children.Remove(lbe);
+			PurchaseDate = Children.Min(c => c.LibraryBook.DateAdded).ToString("d");
+			int bookLenMins = Children.Sum(c => c.LibraryBook.Book.LengthInMinutes);
+			Length = bookLenMins == 0 ? "" : $"{bookLenMins / 60} hr {bookLenMins % 60} min";
+		}
+
+		public void UpdateLibraryBook(LibraryBook libraryBook)
+		{
+			if (AudibleProductId != libraryBook.Book.AudibleProductId)
+				throw new Exception("Invalid grid entry update. IDs must match");
+
+			setLibraryBook(libraryBook);
+		}
+
+		private void setLibraryBook(LibraryBook libraryBook)
+		{
+			LibraryBook = libraryBook;
+
 			Title = Book.Title;
 			Series = Book.SeriesNames();
 			//Ratings are changed using Update(), which is a problem for Avalonia data bindings because
@@ -81,6 +102,8 @@ namespace LibationAvalonia.ViewModels
 			PurchaseDate = Children.Min(c => c.LibraryBook.DateAdded).ToString("d");
 			int bookLenMins = Children.Sum(c => c.LibraryBook.Book.LengthInMinutes);
 			Length = bookLenMins == 0 ? "" : $"{bookLenMins / 60} hr {bookLenMins % 60} min";
+
+			this.RaisePropertyChanged(nameof(MyRating));
 		}
 
 

Source/LibationAvalonia/Views/MainWindow.axaml.cs

@@ -51,7 +51,7 @@ namespace LibationAvalonia.Views
 			{
 				this.LibraryLoaded += MainWindow_LibraryLoaded;
 
-				LibraryCommands.LibrarySizeChanged += async (_, _) => await _viewModel.ProductsDisplay.DisplayBooksAsync(DbContexts.GetLibrary_Flat_NoTracking(includeParents: true));
+				LibraryCommands.LibrarySizeChanged += async (_, _) => await _viewModel.ProductsDisplay.UpdateGridAsync(DbContexts.GetLibrary_Flat_NoTracking(includeParents: true));
 				Closing += (_, _) => this.SaveSizeAndLocation(Configuration.Instance);
 			}
 			Closing += MainWindow_Closing;
@@ -67,7 +67,7 @@ namespace LibationAvalonia.Views
 			if (QuickFilters.UseDefault)
 				await performFilter(QuickFilters.Filters.FirstOrDefault());
 
-			await _viewModel.ProductsDisplay.DisplayBooksAsync(dbBooks);
+			_viewModel.ProductsDisplay.BindToGrid(dbBooks);
 		}
 
 		private void InitializeComponent()

Source/LibationAvalonia/Views/ProductsDisplay.axaml.cs

@@ -44,7 +44,7 @@ namespace LibationAvalonia.Views
 				};
 
 				var pdvm = new ProductsDisplayViewModel();
-				_ = pdvm.DisplayBooksAsync(sampleEntries);
+				pdvm.BindToGrid(sampleEntries);
 				DataContext = pdvm;
 
 				return;