using System;
using System.Collections.Generic;
using MongoDB.Bson.Serialization.Attributes;
using MongoDB.Bson.Serialization.IdGenerators;
using MongoDB.Driver;
using MongoDB.Driver.Linq;

namespace Mongo2
{
    class Group
    {
        [BsonId(IdGenerator = typeof(GuidGenerator))]
        public Guid ID { get; set; }
        public string Name { get; set; }
        public List<Brand> Brands { get; set; }
    }

    class Brand
    {
        public string Name { get; set; }
        public List<Model> Models { get; set; }
    }

    class Model
    {
        public string Name { get; set; }
        public int Produced { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            MongoClient client = new MongoClient("mongodb://127.0.0.1:32768");
            var db = client.GetDatabase("test");
            var collection = db.GetCollection<Group>("groups");

            var fca = new Group { Name = "FCA" };

            var alfaRomeo = new Brand { Name = "Alfra Romeo" };
            var jeep = new Brand { Name = "Jeep" };
            var ferrari = new Brand { Name = "Ferrari"};

            var laFerrari = new Model { Name = "LaFerrari", Produced = 4 };

            var wrangler = new Model { Name = "Wrangler", Produced = 3 };
            var compass = new Model { Name = "Compass", Produced = 8 };

            var giulietta = new Model { Name = "Giulietta", Produced = 7 };
            var giulia = new Model { Name = "Giulia", Produced = 8 };
            var _4c = new Model { Name = "4C", Produced = 6 };        

            fca.Brands = new List<Brand> { ferrari, alfaRomeo, jeep };

            ferrari.Models = new List<Model> { laFerrari };
            jeep.Models = new List<Model> { wrangler, compass };
            alfaRomeo.Models = new List<Model> { giulietta, giulia, _4c };

            collection.InsertOne(fca);                 

            Console.WriteLine("press enter to continue");
            Console.ReadLine();

            var models = collection.AsQueryable().SelectMany(g => g.Brands).SelectMany(b => b.Models).ToList();
            Console.WriteLine(models.Count);  //returns 0 instead of 6
            Console.ReadLine();

        }
    }
}