using System;

using System.Collections.Generic;

using System.Linq;

using Microsoft.EntityFrameworkCore;

using System.Linq.Expressions;

using System.ComponentModel.DataAnnotations;

​

public class Program

{

    private static BooksContext _db;

    private const string WARISDIRIE_AUTHORNAME = "Waris Dirie";

    private const string CATHLENEMILLER_AUTHORNAME = "Cathlene Miller";

    private const string DESERTFLOWER_BOOKTITLE = "KWIAT PUSTYNI";

    public static void Main()

    {

        _db = new BooksContext();

​

        //  Create dataset

        SeedDataContext();

​

        int id = _db.Authors.Where(x => x.FullName == WARISDIRIE_AUTHORNAME).Select(x => x.Id).Single();

        var authorDetails = GetAuthorById(id);

        Console.WriteLine("Id of Author: {0}", id);

​

​

        // Trying to serialize the whole object requires ignoring the recursive relationship between Author => Book => (same) Author

        Console.WriteLine(Newtonsoft.Json.JsonConvert.SerializeObject(authorDetails, new Newtonsoft.Json.JsonSerializerSettings

                                                                      { 

                                                                          Formatting = Newtonsoft.Json.Formatting.Indented,  

                                                                          ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore

                                                                      }));

        // To prove that EF did actually load both references:

        Console.WriteLine(Newtonsoft.Json.JsonConvert.SerializeObject(authorDetails.Authors_Books.First().Book, new Newtonsoft.Json.JsonSerializerSettings

                                                                      { 

                                                                          Formatting = Newtonsoft.Json.Formatting.Indented,  

                                                                          ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore

                                                                      }));

    }

    public static Author GetAuthorById(int id)

    {

        var bookDetails = _db.Authors

            .Include(ab => ab.Authors_Books)

                .ThenInclude(b => b.Book)

                    .ThenInclude(book => book.Authors_Books)

            .FirstOrDefault(n => n.Id == id);

        return bookDetails;

    }

    private static void SeedDataContext()

    {

        var create = _db.Database.GenerateCreateScript();

        //nsole.WriteLine(create);

        _db.Database.EnsureCreated();

        _db.Database.Migrate();

        var warisDirieAuthor = _db.Authors.FirstOrDefault(x => x.FullName == WARISDIRIE_AUTHORNAME);

        if (warisDirieAuthor == null)

        {

            warisDirieAuthor = new Author 

            { 

                FullName = WARISDIRIE_AUTHORNAME,

                Bio = "Waris Dirie (Somali: Waris Diiriye) (born in 1965) is a Somali model, author, actress and human rights activist in the fight against Female Genital Mutilation (FGM). From 1997 to 2003, she was a UN special ambassador against female genital mutilation. In 2002 she founded her own organization in Vienna, the Desert Flower Foundation.",

                ImageURL = "https://upload.wikimedia.org/wikipedia/commons/thumb/0/05/Waris_Dirie%2C_2018_during_her_visit_to_Sierra_Leone.jpg/220px-Waris_Dirie%2C_2018_during_her_visit_to_Sierra_Leone.jpg"

            };

            _db.Authors.Add(warisDirieAuthor);

        }

        var cathleneMillerAuthor = _db.Authors.FirstOrDefault(x => x.FullName == CATHLENEMILLER_AUTHORNAME);

        if (cathleneMillerAuthor == null)

        {

            cathleneMillerAuthor = new Author

            { 

                FullName = CATHLENEMILLER_AUTHORNAME ,

                Bio = "Cathleen Miller is an internationally best-selling American nonfiction writer based in California. Her 2013 book, Champion of Choice, is the biography of United Nations leader Nafis Sadik." + 

                      "she is also the author of Desert Flower (1998), co-written with Waris Dirie—a Somali nomad turned model turned activist—who shared her experience with female genital mutilation to bring about global awareness.[8][9] The book has been cited by the United Nations as having played a major role in the advocacy against female genital mutilation. Desert Flower was made into a feature film in 2009 and released in 34 countries. The print version sold over 11 million copies worldwide and has been translated into more than 55 languages.",

                ImageURL = "https://www.svlaureates.org/wp-content/uploads/sites/www.svlaureates.org/images/2018/05/cathleen-miller-1024x1024-300x300.jpg"

            };

            _db.Authors.Add(cathleneMillerAuthor);

        }           

        _db.SaveChanges();

        var dersertFlowerBook = _db.Books.FirstOrDefault(x => x.Title == DESERTFLOWER_BOOKTITLE);

        if (dersertFlowerBook == null)

        {

            dersertFlowerBook = new Book { Title = DESERTFLOWER_BOOKTITLE };

            dersertFlowerBook.Authors_Books.Add(new Author_Book { Author = warisDirieAuthor });

            dersertFlowerBook.Authors_Books.Add(new Author_Book { Author = cathleneMillerAuthor });

            _db.Books.Add(dersertFlowerBook);

            _db.SaveChanges();

        }

    }

}

​

​

  public class BooksContext : DbContext

    {

        public DbSet<Book> Books { get; set; }

        public DbSet<Author> Authors { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder options) 

            => options.UseSqlServer(FiddleHelper.GetConnectionStringSqlServer());

        protected override void OnModelCreating(ModelBuilder modelBuilder)

        {

            base.OnModelCreating(modelBuilder);

            modelBuilder.Entity<Book>().HasMany(b => b.Authors_Books).WithOne(ab => ab.Book).HasForeignKey(ab => ab.BookId);

            modelBuilder.Entity<Author>().HasMany(a => a.Authors_Books).WithOne(ab => ab.Author).HasForeignKey(ab => ab.AuthorId);

        }

​

    }

​

 public class Book 

 {

    [Key]

    public int Id { get; set; }

    public string Title { get; set; }

    public DateTime RelaseDate { get; set; }

    public string Description { get; set; }

    public string ImageURL { get; set; }

    public bool IsBorrowed { get; set; }

    public string ISBN { get; set; }

​

//    //Relationships

//    public int PublisherId { get; set; }

//    [ForeignKey("PublisherId")]

//    public virtual Publisher Publisher { get; set; }

​

//    public int CategoryId { get; set; }

//    [ForeignKey("CategoryId")]

//    public virtual Category Categories { get; set; }

​

    public virtual ICollection <Author_Book> Authors_Books { get; set; } = new HashSet<Author_Book>();

}

public class Author_Book

{

    [Key]

    public int Id { get; set; }

    public int AuthorId { get; set; }

    public virtual Author Author { get; set; }

​

    public int BookId { get; set; }

    public virtual Book Book { get; set; }

}

public class Author

{

    [Key]

    public int Id { get; set; }

    [Display(Name = "Autor")]

    [Required(ErrorMessage = "Author jest wymagany")]

    public string FullName { get; set; }

​

    [Display(Name = "Biografia")]

    [Required(ErrorMessage = "Biografia jest wymagana")]

    public string Bio { get; set; }

​

    [Display(Name = "Zdjęcie")]

    public string ImageURL { get; set; }

​

    //Relationships

    public virtual ICollection<Author_Book> Authors_Books { get; set; } = new HashSet<Author_Book>();

//    public virtual ICollection<Author_Publisher> Author_Publisher { get; set; }

//    public virtual ICollection<Author_Category> Author_Category { get; set; }

}

​

​

​