ObjectLounge - An Object-Oriented Database Framework

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;
using System.Collections;
using System.Reflection;
using Technewlogic.ObjectLounge.Helper;
using Technewlogic.ObjectLounge.Framework.Proxy;
using Technewlogic.ObjectLounge.Framework.Transactions;

namespace Technewlogic.ObjectLounge.Framework.BaseConcerns
{
	internal abstract class OneBase : EntitySync
	{
		public OneBase(IUnitOfWorkConcern master)
			: base(master)
		{
		}

		#region EntitySync

		public override bool HasValue(object value)
		{
			if (value == null)
				throw new ArgumentNullException("Value");

			var currentValue = GetValue();
			if (currentValue == null)
				return false;
			else
				return currentValue.Equals(value);
		}

		#endregion

		protected override void OnStateChange()
		{
			base.OnStateChange();

			if (GetValue() != null)
				_strategy.StateChange(GetValue(), WillBeInDB);
		}

		protected abstract Type GetTargetType();

		private bool _isInitialized = false;

		private IUnitOfWorkConcern _innerValue;
		private IUnitOfWorkConcern InnerValue
		{
			get
			{
				//// Lazy initializing
				//if (!_isInitialized)
				//    Initialize();

				return _innerValue;
			}
			set { _innerValue = value; }
		}

		internal IUnitOfWorkConcern GetValue()
		{
			return InnerValue;
		}

		internal void SetValue(IUnitOfWorkConcern value)
		{
			if (InnerValue == value)
				return;

			OnBeforeValueSet(value);

			if (InnerValue != null)
				_strategy.Remove(InnerValue, WillBeInDB);
			if (value != null)
				_strategy.Add(value, WillBeInDB);

			InnerValue = value;
		}

		//private void Initialize()
		//{
		//    EntityCollection ec = _entityContext.GetEntityCollection(GetTargetType());
		//    var value = MasterIsChild()
		//        ? ec.GetEntityByForeignKeyFieldOfEntity(_master)
		//        : ec.GetEntityByPrimaryKeyPropertyOfEntity(_master);

		//    //_innerValue = new ShadowStorageRef<IUnitOfWorkConcern>(value, _master);
		//    _innerValue = value;

		//    _isInitialized = true;
		//}

		protected abstract void OnBeforeValueSet(IUnitOfWorkConcern value);

		internal override void AddTarget(IEnumerable<IUnitOfWorkConcern> children)
		{
			if (_isInitialized)
				throw new ApplicationException("The entity is already initialized."); // IMP: besser machen
			if (children.Count() > 1)
				throw new ApplicationException("In a OneBase, only 1 child can be added at initialization.");

			_innerValue = children.FirstOrDefault();

			if (_innerValue != null && GetTargetType() != _innerValue.GetType().BaseType)
				throw new ApplicationException("The expected type is not the initialization type.");

			_isInitialized = true;
		}

		internal override IEnumerable<IUnitOfWorkConcern> GetTargets()
		{
			if (InnerValue == null)
				return new IUnitOfWorkConcern[] { };
			else
				return new IUnitOfWorkConcern[] { (IUnitOfWorkConcern)InnerValue };
		}
	}
}