Buecherwurm/Catalogue.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.Json;

namespace Bücherwurm
{
    class Catalogue
    {
        private List<IProduct> Products {get; set;}

        private int NextId {get; set;}

        public Catalogue()
        {
            Products = new List<IProduct>();
            NextId = 1;
        }

        public void Import(string JsonString)
        {
            var IntermediateBooks = JsonSerializer.Deserialize<List<IProduct>>(JsonString);
            foreach (var Ibook in IntermediateBooks)
            {
                Ibook.OverwriteNullId(NextId);
                NextId += 1;
            }
            Products = IntermediateBooks;
        }

        public void AddBook(string Title, string Author,
            string Country, string ILink, string Link,
            string Language, int Pages, int Year)
        {
            Products.Add(new Book(NextId, Title, Author, Country, ILink, Link, Language, Pages, Year));
            NextId = NextId++;
        }

        public void Add(IProduct product)
        {
            Products.Add(product);
        }
        
        public void Remove(int bookID)
        {
            Products.RemoveAll(book => book.ProductId == bookID);
        }

        public List<Book> GetBooks()
        {
            return Products.FindAll(prod => prod.Category == "book").Cast<Book>().ToList();
        }

        public Book LookupBook(int bookId)
        {
            return (Book)Products.Find(book => book.ProductId == bookId && book.Category == "book");
        }
    }
}