namespace Cqrs.Persistence
{
	using System;
	using System.Collections.Generic;
	using Domain;

	public class DomainUnitOfWork : IUnitOfWork
	{
		private readonly ICollection<IAggregate> inserted = new HashSet<IAggregate>();
		private readonly ICollection<IAggregate> updated = new HashSet<IAggregate>();
		private readonly ICollection<IAggregate> deleted = new HashSet<IAggregate>();
		private readonly IStoreEvents eventStore;
		private bool completed;
		private bool disposed;

		public DomainUnitOfWork(IStoreEvents eventStore)
		{
			this.eventStore = eventStore;
		}

		public void RegisterNew(IAggregate aggregate)
		{
			this.inserted.Add(aggregate);
			this.updated.Remove(aggregate);
			this.deleted.Remove(aggregate);
		}
		public void RegisterDirty(IAggregate aggregate)
		{
			this.inserted.Remove(aggregate);
			this.updated.Add(aggregate);
			this.deleted.Remove(aggregate);
		}
		public void RegisterDeleted(IAggregate aggregate)
		{
			this.inserted.Remove(aggregate);
			this.updated.Remove(aggregate);
			this.deleted.Add(aggregate);
		}

		public void Complete()
		{
			if (this.deleted.Count > 0)
				throw new NotSupportedException();

			if (this.completed)
				return;

			foreach (var aggregate in this.inserted)
			{
				this.eventStore.RegisterNewAggregate(aggregate);
				this.eventStore.SaveUncommittedEvents(aggregate);
			}

			foreach (var aggregate in this.updated)
				this.eventStore.SaveUncommittedEvents(aggregate);

			this.inserted.Clear();
			this.updated.Clear();
			this.deleted.Clear();
		}

		public void Dispose()
		{
			this.Dispose(true);
			GC.SuppressFinalize(this);
		}
		protected virtual void Dispose(bool disposing)
		{
			if (!disposing || this.disposed)
				return;

			this.disposed = this.completed = true;

			this.inserted.Clear();
			this.updated.Clear();
			this.deleted.Clear();
		}
	}
}