Libation/Source/LibationUiBase/GridView/QueryExtensions.cs

using DataLayer;
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;

namespace LibationUiBase.GridView;

public static class QueryExtensions
{
	public static IEnumerable<LibraryBookEntry> BookEntries(this IEnumerable<GridEntry> gridEntries)
		=> gridEntries.OfType<LibraryBookEntry>();

	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;

		try
		{
			//Parent books will always have exactly 1 SeriesBook due to how
			//they are imported in ApiExtended.getChildEpisodesAsync()
			return gridEntries.SeriesEntries().FirstOrDefault(
				lb =>
				seriesEpisode.Book.SeriesLink.Any(
					s => s.Series.AudibleSeriesId == lb.LibraryBook.Book.SeriesLink.Single().Series.AudibleSeriesId));
		}
		catch (Exception ex)
		{
			Serilog.Log.Error(ex, "Query error in {0}", nameof(FindSeriesParent));
			return null;
		}
	}

	public static bool SearchSetsDiffer(this HashSet<GridEntry>? searchSet, HashSet<GridEntry>? otherSet)
		=> searchSet is null != otherSet is null ||
				(searchSet is not null &&
				otherSet is not null &&
				searchSet.Intersect(otherSet).Count() != searchSet.Count);

	[return: NotNullIfNotNull(nameof(searchResultSet))]
	public static HashSet<GridEntry>? FilterEntries(this IEnumerable<GridEntry> entries, LibationSearchEngine.SearchResultSet? searchResultSet)
	{
		if (searchResultSet is null)
			return null;
		var booksFilteredIn = entries.IntersectBy(searchResultSet.Docs.Select(d => d.ProductId), l => l.AudibleProductId);

		//Find all series containing children that match the search criteria
		var seriesFilteredIn = booksFilteredIn.OfType<LibraryBookEntry>().Select(lbe => lbe.Parent).OfType<SeriesEntry>().Distinct();

		return booksFilteredIn.Concat(seriesFilteredIn).ToHashSet();
	}
}