ProjectLib/ProjectLibrary/Repositores/Implementations/LibraryRepository.cs

using ProjectLibrary.Entites;
using ProjectLibrary.Entities;
using ProjectLibrary.Repositories;
using System.Collections.Generic;
using System.Linq;

namespace ProjectLibrary.Repositories.Implementations
{
    public class LibraryRepository : ILibraryRepository
    {
        private readonly List<Library> _libraries = new List<Library>();

        public void CreateLibrary(Library library)
        {
            _libraries.Add(library);
        }

        public void DeleteLibrary(int id)
        {
            var library = _libraries.FirstOrDefault(l => l.Id == id);
            if (library != null)
            {
                _libraries.Remove(library);
            }
        }

        public Library ReadLibraryById(int id)
        {
            return _libraries.FirstOrDefault(l => l.Id == id) ?? Library.CreateEntity(id, "Unknown Library", "Unknown Address");
        }

        public IEnumerable<Library> ReadLibraries()
        {
            return _libraries;
        }

        public void UpdateLibrary(Library library)
        {
            var existingLibrary = _libraries.FirstOrDefault(l => l.Id == library.Id);
            if (existingLibrary != null)
            {
                _libraries.Remove(existingLibrary);
                _libraries.Add(library);
            }
        }
    }
}