Implement IProduct interface

Administration.cs

@@ -25,7 +25,7 @@ namespace Bücherwurm
             foreach (var book in BookList)
             {
                 Console.WriteLine("---");
-                Console.WriteLine("ID: {0}", book.BookId);
+                Console.WriteLine("ID: {0}", book.ProductId);
                 Console.WriteLine("Author: {0}", book.Author);
                 Console.WriteLine("Titel: {0}", book.Title);
             }
@@ -71,7 +71,7 @@ namespace Bücherwurm
                     case "j":
                     {
                         Correct = true;
-                        Catalogue.Add(Title, Author, Country, ImgLink, Link, Language, int.Parse(Pages), int.Parse(Year));
+                        Catalogue.AddBook(Title, Author, Country, ImgLink, Link, Language, int.Parse(Pages), int.Parse(Year));
                         Console.WriteLine("Buch wurde hinzugefügt.");
                         break;
                     }

Book.cs

@@ -2,11 +2,8 @@ using System.Text.Json.Serialization;
 
 namespace Bücherwurm
 {
-    class Book
+    class Book : IProduct
     {
-        [JsonIgnoreAttribute]
-        public int BookId {get; set;}
-
         [JsonPropertyName("title")]
         public string Title {get; set;}
 
@@ -16,9 +13,6 @@ namespace Bücherwurm
         [JsonPropertyName("country")]
         public string Country {get; set;}
 
-        [JsonPropertyName("imageLink")]
-        public string ImageLink {get; set;}
-
         [JsonPropertyName("link")]
         public string Link {get; set;}
 
@@ -30,12 +24,19 @@ namespace Bücherwurm
 
         [JsonPropertyName("year")]
         public int Year {get; set;}
+        [JsonIgnore]
+        public int ProductId { get; set; }
+        [JsonIgnore]
+        public string Category { get; }
+        [JsonPropertyName("imageLink")]
+        public string ImageLink { get; set; }
 
         public Book(int Id, string Title, string Author,
             string Country, string ILink, string Link, string Language,
             int Pages, int Year)
         {
-            BookId = Id;
+            ProductId = Id;
+            Category = "book";
             this.Title = Title;
             this.Author = Author;
             this.Country = Country;
@@ -50,12 +51,12 @@ namespace Bücherwurm
         {
             
         }
-
-        public void OverwriteNullId(int Id)
+        
+        public void OverwriteNullId(int id)
         {
-            if (BookId == 0)
+            if (ProductId == 0)
             {
-                BookId = Id;
+                ProductId = id;
             }
         }
     }

Catalogue.cs

@@ -1,53 +1,59 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.Json;
 
 namespace Bücherwurm
 {
     class Catalogue
     {
-        private List<Book> Books {get; set;}
+        private List<IProduct> Products {get; set;}
 
         private int NextId {get; set;}
 
         public Catalogue()
         {
-            Books = new List<Book>();
+            Products = new List<IProduct>();
             NextId = 1;
         }
 
         public void Import(string JsonString)
         {
-            var intermediateBooks = JsonSerializer.Deserialize<List<Book>>(JsonString);
-            foreach (var ibook in intermediateBooks)
+            var IntermediateBooks = JsonSerializer.Deserialize<List<IProduct>>(JsonString);
+            foreach (var Ibook in IntermediateBooks)
             {
-                ibook.OverwriteNullId(NextId);
-                NextId = NextId + 1;
+                Ibook.OverwriteNullId(NextId);
+                NextId += 1;
             }
-            Books = intermediateBooks;
+            Products = IntermediateBooks;
         }
 
-        public void Add(string Title, string Author,
+        public void AddBook(string Title, string Author,
             string Country, string ILink, string Link,
             string Language, int Pages, int Year)
         {
-            Books.Add(new Book(NextId, Title, Author, Country, ILink, Link, Language, Pages, Year));
+            Products.Add(new Book(NextId, Title, Author, Country, ILink, Link, Language, Pages, Year));
             NextId = NextId++;
         }
 
-        public void Remove(int BookID)
+        public void Add(IProduct product)
         {
-            Books.RemoveAll(book => book.BookId == BookID);
+            Products.Add(product);
+        }
+        
+        public void Remove(int bookID)
+        {
+            Products.RemoveAll(book => book.ProductId == bookID);
         }
 
         public List<Book> GetBooks()
         {
-            return Books;
+            return Products.FindAll(prod => prod.Category == "book").Cast<Book>().ToList();
         }
 
-        public Book LookupBook(int BookId)
+        public Book LookupBook(int bookId)
         {
-            return Books.Find(book => book.BookId == BookId);
+            return (Book)Products.Find(book => book.ProductId == bookId && book.Category == "book");
         }
     }
 }

Inventory.cs

@@ -13,9 +13,9 @@ namespace Bücherwurm
             NextId = 1;
         }
 
-        public void Add(Book Book)
+        public void Add(IProduct Book)
         {
-            InventoryList.Add(new Item(NextId, Book.BookId));
+            InventoryList.Add(new Item(NextId, Book.ProductId));
             NextId = NextId + 1;
         }