#region Apache Notice
/*****************************************************************************
 * $Revision: 374175 $
 * $LastChangedDate$
 * $LastChangedBy$
 * 
 * iBATIS.NET Data Mapper
 * Copyright (C) 2008/2005 - The Apache Software Foundation
 *  
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 ********************************************************************************/
#endregion

using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using Apache.Ibatis.DataMapper.Model.ResultMapping;
using Apache.Ibatis.DataMapper.Exceptions;
using Apache.Ibatis.DataMapper.Scope;
using Apache.Ibatis.Common.Contracts;

namespace Apache.Ibatis.DataMapper.MappedStatements.PropertyStrategy
{
	/// <summary>
	/// <see cref="IPropertyStrategy"/> implementation when a 'select' attribute exists
	/// on a <see cref="ResultProperty"/>
	/// </summary>
	public class SelectStrategy : IPropertyStrategy
	{
		private readonly IPropertyStrategy selectStrategy = null;


        /// <summary>
        /// Initializes a new instance of the <see cref="SelectStrategy"/> class.
        /// </summary>
        /// <param name="mapping">The mapping.</param>
        /// <param name="selectArrayStrategy">The select array strategy.</param>
        /// <param name="selectGenericListStrategy">The select generic list strategy.</param>
        /// <param name="selectListStrategy">The select list strategy.</param>
        /// <param name="selectObjectStrategy">The select object strategy.</param>
		public SelectStrategy(ResultProperty mapping,
            IPropertyStrategy selectArrayStrategy,
            IPropertyStrategy selectGenericListStrategy,
            IPropertyStrategy selectListStrategy,
            IPropertyStrategy selectObjectStrategy)
		{
            Contract.Require.That(selectArrayStrategy, Is.Not.Null).When("retrieving argument selectArrayStrategy in SelectStrategy constructor");
            Contract.Require.That(selectGenericListStrategy, Is.Not.Null).When("retrieving argument selectGenericListStrategy in SelectStrategy constructor");
            Contract.Require.That(selectListStrategy, Is.Not.Null).When("retrieving argument selectListStrategy in SelectStrategy constructor");
            Contract.Require.That(selectObjectStrategy, Is.Not.Null).When("retrieving argument selectObjectStrategy in SelectStrategy constructor");

			// Collection object or .NET object		
			if (mapping.SetAccessor.MemberType.BaseType == typeof(Array))
			{
                selectStrategy = selectArrayStrategy;
			}
            else if (mapping.SetAccessor.MemberType.IsGenericType &&
                 typeof(IList<>).IsAssignableFrom(mapping.SetAccessor.MemberType.GetGenericTypeDefinition()) )
            {
                selectStrategy = selectGenericListStrategy;
            }
            // Check if the object to Map implement 'IList' or is IList type
			// If yes the ResultProperty is map to a IList object
            else if (typeof(IList).IsAssignableFrom(mapping.SetAccessor.MemberType))
			{
                selectStrategy = selectListStrategy;
			}

			else // The ResultProperty is map to a .Net object
			{
                selectStrategy = selectObjectStrategy;
			}
		}
	
		#region IPropertyStrategy members

		///<summary>
		/// Sets value of the specified <see cref="ResultProperty"/> on the target object
		/// when a 'select' attribute exists
		/// on the <see cref="ResultProperty"/> are empties.
		/// </summary>
		/// <param name="request">The request.</param>
		/// <param name="resultMap">The result map.</param>
		/// <param name="mapping">The ResultProperty.</param>
		/// <param name="target">The target.</param>
		/// <param name="reader">The reader.</param>
		/// <param name="selectKeys">The keys</param>
		public void Set(RequestScope request, IResultMap resultMap, 
			ResultProperty mapping, ref object target, IDataReader reader, object selectKeys)
		{
			string paramString = mapping.ColumnName;
			object keys = null;
			bool wasNull = false;

			#region Finds the select keys.
			if (paramString.IndexOf(',')>0 || paramString.IndexOf('=')>0) // composite parameters key
			{
				IDictionary keyMap = new Hashtable();
				keys = keyMap;
				// define which character is seperating fields
				char[] splitter  = {'=',','};

				string[] paramTab = paramString.Split(splitter);
				if (paramTab.Length % 2 != 0) 
				{
					throw new DataMapperException("Invalid composite key string format in '"+mapping.PropertyName+". It must be: property1=column1,property2=column2,..."); 
				}
				IEnumerator enumerator = paramTab.GetEnumerator();
				while (!wasNull && enumerator.MoveNext()) 
				{
					string hashKey = ((string)enumerator.Current).Trim();
                    if (paramString.Contains("="))// old 1.x style multiple params
                    {
                        enumerator.MoveNext();
                    }
                    object hashValue = reader.GetValue(reader.GetOrdinal(((string)enumerator.Current).Trim()));

					keyMap.Add(hashKey, hashValue );
					wasNull = (hashValue == DBNull.Value);
				}
			} 
			else // single parameter key
			{
				keys = reader.GetValue(reader.GetOrdinal(paramString));
				wasNull = reader.IsDBNull(reader.GetOrdinal(paramString));
			}
			#endregion

			if (wasNull) 
			{
				// set the value of an object property to null
                mapping.Set(target, null);
			} 
			else // Collection object or .Net object
			{
				selectStrategy.Set(request, resultMap, mapping, ref target, reader, keys);
			}		
		}

        /// <summary>
        /// Gets the value of the specified <see cref="ResultProperty"/> that must be set on the target object.
        /// </summary>
        /// <param name="request">The request.</param>
        /// <param name="resultMap">The result map.</param>
        /// <param name="mapping">The mapping.</param>
        /// <param name="reader">The reader.</param>
		/// <param name="target">The target object</param>
		public object Get(RequestScope request, IResultMap resultMap, ResultProperty mapping, ref object target, IDataReader reader)
        {
            throw new NotSupportedException("Get method on ResultMapStrategy is not supported");
        }	    
		#endregion
	}
}