LibraryApp/LibraryApp.Domain/BookCountReport.cs

using LibraryApp.Domain.Entities;

namespace LibraryApp.Domain;

public class BookCountReport
{
    public ShelfId ShelfId { get; }
    public DateTime CountedAt { get; }
    public IReadOnlyList<BookInstance> MissingInstances { get; }
    public int TotalExpected { get; }
    public int TotalFound { get; }

    public BookCountReport(
        ShelfId shelfId,
        DateTime countedAt,
        IReadOnlyList<BookInstance> allInstancesOnShelf,
        IReadOnlyList<BookInstanceBarcode> scannedBarcodes)
    {
        ShelfId = shelfId;
        CountedAt = countedAt;
        TotalExpected = allInstancesOnShelf.Count;

        var scannedSet = scannedBarcodes.Select(b => b.Barcode).ToHashSet();
        MissingInstances = allInstancesOnShelf
            .Where(i => !scannedSet.Contains(i.Barcode.Barcode))
            .ToList();

        TotalFound = TotalExpected - MissingInstances.Count;
    }
}