using System.Collections.Generic;
using System.Linq;
using Microsoft.EntityFrameworkCore;

namespace DataLayer
{
    // only library importing should use tracking. All else should be NoTracking.
    // only library importing should directly query Book. All else should use LibraryBook
    public static class LibraryQueries
	{
        //// tracking is a bad idea for main grid. it prevents anything else from updating entities unless getting them from the grid
		//public static List<LibraryBook> GetLibrary_Flat_WithTracking(this LibationContext context)
		//	=> context
		//		.Library
		//		.GetLibrary()
		//		.ToList();

		public static List<LibraryBook> GetLibrary_Flat_NoTracking(this LibationContext context)
            => context
                .Library
                .AsNoTrackingWithIdentityResolution()
                .GetLibrary()
                .ToList();

        public static LibraryBook GetLibraryBook_Flat_NoTracking(this LibationContext context, string productId)
            => context
                .Library
                .AsNoTrackingWithIdentityResolution()
                .GetLibraryBook(productId);

        public static LibraryBook GetLibraryBook(this IQueryable<LibraryBook> library, string productId)
            => library
                .GetLibrary()
                .SingleOrDefault(lb => lb.Book.AudibleProductId == productId);

        /// <summary>This is still IQueryable. YOU MUST CALL ToList() YOURSELF</summary>
        public static IQueryable<LibraryBook> GetLibrary(this IQueryable<LibraryBook> library)
            => library
                // owned items are always loaded. eg: book.UserDefinedItem, book.Supplements
                .Include(le => le.Book).ThenInclude(b => b.SeriesLink).ThenInclude(sb => sb.Series)
                .Include(le => le.Book).ThenInclude(b => b.ContributorsLink).ThenInclude(c => c.Contributor)
                .Include(le => le.Book).ThenInclude(b => b.Category).ThenInclude(c => c.ParentCategory);
    }
}