using Microsoft.EntityFrameworkCore;

using System.Collections.Generic;

using System.Linq;

using System;

​

namespace EFTest

{

    public class Blog

    {

        public int BlogId { get; set; }

        public string Url { get; set; }

        public int? PrimaryThingId { get; set; }

        public virtual Thing PrimaryThing {get; set;}

        public virtual ICollection<BlogThing> BlogThings { get; set; }

    }

    public class Thing {

        public Thing()

        {

            PrimaryBlogs = new HashSet<Blog>();

            BlogThings = new HashSet<BlogThing>();

        }

        public int ThingId { get; set; }

        public ICollection<Blog> PrimaryBlogs {get; set;}

        public virtual ICollection<BlogThing> BlogThings {get; set;}

    }

    public class BlogThing

    {

        public int BlogThingId {get; set;}

        public int? BlogId {get; set;}

        public int? ThingId {get; set;}

        public virtual Blog Blog { get; set; }

        public virtual Thing Thing { get; set; }

    }

​

    public class BloggingContext : DbContext

    {

        public BloggingContext(){ }

​

        public BloggingContext(DbContextOptions<BloggingContext> options)

            : base(options){ }

​

        public DbSet<Blog> Blogs { get; set; }

        public DbSet<Thing> Things {get; set;}

        public DbSet<BlogThing> BlogThings {get; set;}

        protected override void OnModelCreating(ModelBuilder modelBuilder)

        {

            modelBuilder.Entity<Blog>().HasMany(x => x.BlogThings).WithOne(x => x.Blog);

            modelBuilder.Entity<Blog>().HasOne(x => x.PrimaryThing).WithMany(x => x.PrimaryBlogs);

            modelBuilder.Entity<Thing>().HasMany(x => x.BlogThings).WithOne(x => x.Thing);

            modelBuilder.Entity<Thing>().HasMany(x => x.PrimaryBlogs).WithOne(x => x.PrimaryThing);

            modelBuilder.Entity<BlogThing>().HasOne(x => x.Blog).WithMany(x => x.BlogThings);

            modelBuilder.Entity<BlogThing>().HasOne(x => x.Thing).WithMany(x => x.BlogThings);

        }

    }

​

    public class BlogService

    {

        private BloggingContext _context;

​

        public BlogService(BloggingContext context)

        {

            _context = context;

        }

​

        public void Add(string url)

        {

            var blog = new Blog { Url = url };

            _context.Blogs.Add(blog);

            _context.SaveChanges();

        }

​

        public IEnumerable<Blog> Find(string term)

        {

            return _context.Blogs

                .Where(b => b.Url.Contains(term))

                .OrderBy(b => b.Url)

                .ToList();

        }

    }

​

    class Program

    {

        static void Main(string[] args)

        {

            Console.WriteLine("This is an example of using EF Core InMemory Database");

            Console.WriteLine("======================================================");

            Console.WriteLine("");

            var options = new DbContextOptionsBuilder<BloggingContext>()

                .UseInMemoryDatabase(databaseName: "Add_writes_to_database")

                .Options;

​

            // Run the test against one instance of the context

            using (var context = new BloggingContext(options))

            {

                var service = new BlogService(context);

                Console.WriteLine("Adding new blog");

                Console.WriteLine("");

                var blog = new Blog

                {

                    BlogId = 1,

                    Url = "test",

                    PrimaryThingId = 1                  

                };

                var primarything = new Thing

                {

                    ThingId = 1

                };

                var secondarything = new Thing

                {

                    ThingId = 2

                }; 

                var blogthing = new BlogThing

                {

                    BlogThingId = 1,

                    ThingId = 2,

                    BlogId = 1

                };

                context.Blogs.Add(blog);

                context.Things.Add(primarything);

                context.Things.Add(secondarything);

                context.BlogThings.Add(blogthing);

                context.SaveChanges();

            }

​

            // Use a separate instance of the context to verify correct data was saved to database

            using (var context = new BloggingContext(options))

            {

                var things = context.Things

                    .Include(x => x.BlogThings)

                        .ThenInclude(x => x.Blog)

                    .Include(x => x.PrimaryBlogs)

                    .Where(x => x.BlogThings.Any(y => y.Blog.BlogId == 1) || x.PrimaryBlogs.Any(y => y.BlogId == 1))

                    .ToList();

                Console.WriteLine($"Blogs things: {things.Count()}");

            }

​

        }

    }

​

}