#region Apache Notice
/*****************************************************************************
 * $Header: $
 * $Revision: $
 * $Date: $
 * 
 * iBATIS.NET Data Mapper
 * Copyright (C) 2004 - Gilles Bayon
 *  
 * 
 * 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.Specialized;
using System.Configuration;
using IBatisNet.Common.Logging.Impl;

namespace IBatisNet.Common.Logging
{
	/// <summary>
	/// The LogManager can produce ILogFactory for various logging APIs,
	/// most notably for log4net. 
	/// Other implemenations such as
	/// * SimpleLogger
	/// * NoOpLogger are also supported.
	/// </summary>
	public sealed class LogManager
	{
		private static ILoggerFactoryAdapter _adapter = null;
		private static object _loadLock = new object();
		private static readonly string IBATIS_SECTION_LOGGING = "iBATIS/logging";

		/// <summary>
		/// Initializes a new instance of the <see cref="LogManager" /> class. 
		/// </summary>
		/// <remarks>
		/// Uses a private access modifier to prevent instantiation of this class.
		/// </remarks>
		private LogManager()
		{ }

		/// <summary>
		/// 
		/// </summary>
		private static ILoggerFactoryAdapter Adapter
		{
			get
			{
				if ( _adapter == null )
				{
					lock (_loadLock)
					{
						if (_adapter == null)
						{	
							_adapter = BuildLoggerFactoryAdapter();
						}
					}
				}
				return _adapter;				
			}
		}

		/// <summary>
		/// 
		/// </summary>
		/// <param name="type"></param>
		/// <returns></returns>
		public static ILog GetLogger( Type type )
		{
			return Adapter.GetLogger( type );
		}

		/// <summary>
		/// 
		/// </summary>
		/// <param name="name"></param>
		/// <returns></returns>
		public static ILog GetLogger( string name )
		{
			return Adapter.GetLogger(name);
		}

		/// <summary>
		/// 
		/// </summary>
		/// <returns></returns>
		private static ILoggerFactoryAdapter BuildLoggerFactoryAdapter()
		{
			LogSetting setting = null;
			try
			{
				setting = (LogSetting)ConfigurationSettings.GetConfig( IBATIS_SECTION_LOGGING );
			}
			catch ( Exception ex )
			{
				ILoggerFactoryAdapter defaultFactory = BuildDefaultLoggerFactoryAdapter();
				ILog log = defaultFactory.GetLogger( typeof(LogManager) );
				log.Warn( "Unable to read configuration. Using default logger.", ex );
				return defaultFactory;
			}

			if ( setting!= null && !typeof ( ILoggerFactoryAdapter ).IsAssignableFrom( setting.FactoryAdapterType ) )
			{
				ILoggerFactoryAdapter defaultFactory = BuildDefaultLoggerFactoryAdapter();
				ILog log = defaultFactory.GetLogger( typeof(LogManager) );
				log.Warn( "Type " + setting.FactoryAdapterType.FullName + " does not implement ILogFactory. Using default logger" );
				return defaultFactory;
			}

			ILoggerFactoryAdapter instance = null;

			if (setting!=null)
			{
				if (setting.Properties.Count>0)
				{
					try
					{
						object[] args = {setting.Properties};

						instance = (ILoggerFactoryAdapter)Activator.CreateInstance( setting.FactoryAdapterType, args );
					}
					catch ( Exception ex )
					{
						ILoggerFactoryAdapter defaultFactory = BuildDefaultLoggerFactoryAdapter();
						ILog log = defaultFactory.GetLogger( typeof(LogManager) );
						log.Warn( "Unable to create instance of type " + setting.FactoryAdapterType.FullName + ". Using default logger.", ex );
						return defaultFactory;
					}					
				}
				else
				{
					try
					{
						instance = (ILoggerFactoryAdapter)Activator.CreateInstance( setting.FactoryAdapterType );
					}
					catch ( Exception ex )
					{
						ILoggerFactoryAdapter defaultFactory = BuildDefaultLoggerFactoryAdapter();
						ILog log = defaultFactory.GetLogger( typeof(LogManager) );
						log.Warn( "Unable to create instance of type " + setting.FactoryAdapterType.FullName + ". Using default logger.", ex );
						return defaultFactory;
					}
				}
			}
			else
			{
				ILoggerFactoryAdapter defaultFactory = BuildDefaultLoggerFactoryAdapter();
				ILog log = defaultFactory.GetLogger( typeof(LogManager) );
				log.Warn( "Unable to read configuration IBatisNet/logging. Using default logger (ConsoleLogger)." );
				return defaultFactory;
			}

			return instance;
		}

		/// <summary>
		/// 
		/// </summary>
		/// <returns></returns>
		private static ILoggerFactoryAdapter BuildDefaultLoggerFactoryAdapter()
		{
			ILoggerFactoryAdapter simpleLogFactory = new ConsoleOutLoggerFA(new NameValueCollection( null, new CaseInsensitiveComparer() ));
			return simpleLogFactory;
		}
	}
}