using System;
using System.Collections.Generic;

using BLToolkit.Common;
using BLToolkit.Reflection;

namespace BLToolkit.Mapping
{
	public class DictionaryIndexListMapper<T> : IMapDataDestinationList
	{
		public DictionaryIndexListMapper(
			IDictionary<CompoundValue,T> dic,
			MapIndex                     index,
			ObjectMapper                 objectMapper)
		{
			_dic    = dic;
			_mapper = objectMapper;

			_fields = new NameOrIndexParameter[index.Fields.Length];
			_fromSource = new bool[index.Fields.Length];

			for (int i = 0; i < _fields.Length; i++)
			{
				bool fromSource = index.Fields[i].ByName && index.Fields[i].Name[0] == '@';

				_fields[i]     = fromSource ? index.Fields[i].Name.Substring(1) : index.Fields[i];
				_fromSource[i] = fromSource;
				_isFromSource  = _isFromSource ||  fromSource;
				_isFromDest    = _isFromDest   || !fromSource;
			}
		}

		private readonly NameOrIndexParameter[]       _fields;
		private readonly IDictionary<CompoundValue,T> _dic;
		private readonly bool[]                       _fromSource;
		private readonly bool                         _isFromSource;
		private readonly bool                         _isFromDest;
		private          ObjectMapper                 _mapper;
		private          object                       _newObject;
		private          object[]                     _indexValue;

		#region IMapDataDestinationList Members

		private void AddObject()
		{
			if (_newObject != null)
			{
				if (_isFromDest)
					for (int i = 0; i < _fields.Length; i++)
						if (!_fromSource[i])
							_indexValue[i] = _mapper.TypeAccessor[_fields[i]].GetValue(_newObject);

				_dic[new CompoundValue(_indexValue)] = (T)_newObject;
			}
		}

		public virtual void InitMapping(InitContext initContext)
		{
			ISupportMapping sm = _dic as ISupportMapping;

			if (sm != null)
			{
				sm.BeginMapping(initContext);

				if (_mapper != initContext.ObjectMapper)
					_mapper = initContext.ObjectMapper;
			}
		}

		[CLSCompliant(false)]
		public virtual IMapDataDestination GetDataDestination(InitContext initContext)
		{
			return _mapper;
		}

		public virtual object GetNextObject(InitContext initContext)
		{
			AddObject();

			_indexValue = new object[_fields.Length];

			if (_isFromSource)
				for (int i = 0; i < _fields.Length; i++)
					if (_fromSource[i])
						_indexValue[i] = _fields[i].ByName ?
							initContext.DataSource.GetValue(initContext.SourceObject, _fields[i].Name) :
							initContext.DataSource.GetValue(initContext.SourceObject, _fields[i].Index);

			return _newObject = _mapper.CreateInstance(initContext);
		}

		public virtual void EndMapping(InitContext initContext)
		{
			AddObject();

			ISupportMapping sm = _dic as ISupportMapping;

			if (sm != null)
				sm.EndMapping(initContext);
		}

		#endregion
	}
}