using System;
using System.IO;
using System.Linq;
using Db4objects.Db4o;
using Db4objects.Db4o.Linq;

namespace Db4OSeries
{
    public class Program
    {
        private const string FilePath = "database.db4o";

        internal static void Main(string[] args)
        {
            File.Delete(FilePath);
            using (var db = OpenClient())
            {
                db.Store(new SimpleObject() {Name = "Object-1"});
                new Demo1(db).Run();
            }

            Console.ReadKey();
        }


        private static IObjectContainer OpenClient()
        {
            var cfg = Db4oEmbedded.NewConfiguration();
            return Db4oEmbedded.OpenFile(cfg, FilePath);
        }
    }

    internal class Demo1
    {
        private readonly IObjectContainer db;

        public Demo1(IObjectContainer db)
        {
            this.db = db;
        }

        public void Run()
        {
            RestoreObject();
            // Interleaving 1
            {
                var toUpdate = GetTheUpdateObject();
                InOtherThreadThisRanThrought(
                    () =>
                        {
                            var toUpdateT2 = GetTheUpdateObject();
                            toUpdateT2.Amount = toUpdate.Amount*2;
                            toUpdateT2.Price = toUpdate.Price/2;
                            db.Store(toUpdateT2);
                        });
                var sum = toUpdate.Price;
                sum = sum*toUpdate.Amount;
                toUpdate.Sum = sum;
                Console.Out.WriteLine("Sum is=" + toUpdate.Sum + " Expected is 8");
                db.Store(toUpdate);
            }
            RestoreObject();
            // Interleaving 2
            {
                var toUpdate = GetTheUpdateObject();
                var sum = toUpdate.Price;
                InOtherThreadThisRanThrought(
                    () =>
                        {
                            var toUpdateT2 = GetTheUpdateObject();
                            toUpdateT2.Amount = toUpdate.Amount*2;
                            toUpdateT2.Price = toUpdate.Price/2;
                            db.Store(toUpdateT2);
                        });
                sum = sum*toUpdate.Amount;
                toUpdate.Sum = sum;
                Console.Out.WriteLine("Sum is=" + toUpdate.Sum + " Expected is 8");
                db.Store(toUpdate);
            }
        }

        private void RestoreObject()
        {
            var toUpdate = GetTheUpdateObject();
            toUpdate.Amount = 2;
            toUpdate.Price = 4;
        }

        private void InOtherThreadThisRanThrought(Action action)
        {
            action();
        }

        private SimpleObject GetTheUpdateObject()
        {
            return (from SimpleObject o in db
                    where o.Name == "Object-1"
                    select o).First();
        }
    }
}