#region LGPL License
/*
Axiom Graphics Engine Library
Copyright © 2003-2011 Axiom Project Team

The overall design, and a majority of the core engine and rendering code
contained within this library is a derivative of the open source Object Oriented
Graphics Engine OGRE, which can be found at http://ogre.sourceforge.net.
Many thanks to the OGRE team for maintaining such a high quality project.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#endregion LGPL License

#region SVN Version Information
// <file>
//     <license see="http://axiom3d.net/wiki/index.php/license.txt"/>
//     <id value="$Id$"/>
// </file>
#endregion SVN Version Information

#region Namespace Declarations

using System;
using System.Collections.Generic;
using System.IO;


#endregion Namespace Declarations

namespace Axiom.Core
{
	#region LogListenerEventArgs Class
	/// <summary>
	/// 
	/// </summary>
	public class LogListenerEventArgs : EventArgs
	{
		/// <summary>
		/// The message to be logged
		/// </summary>
		public string Message
		{
			get;
			private set;
		}

		/// <summary>
		/// The message level the log is using
		/// </summary>
		public LogMessageLevel Level
		{
			get;
			private set;
		}

		/// <summary>
		/// If we are printing to the console or not
		/// </summary>
		public bool MaskDebug
		{
			get;
			private set;
		}

		/// <summary>
		/// the name of this log (so you can have several listeners for different logs, and identify them)
		/// </summary>
		public string LogName
		{
			get;
			private set;
		}

		/// <summary>
		/// This is called whenever the log recieves a message and is about to write it out
		/// </summary>
		/// <param name="message">The message to be logged</param>
		/// <param name="lml">The message level the log is using</param>
		/// <param name="maskDebug">If we are printing to the console or not</param>
		/// <param name="logName">the name of this log (so you can have several listeners for different logs, and identify them)</param>
		public LogListenerEventArgs( string message, LogMessageLevel lml, bool maskDebug, string logName )
			: base()
		{
			this.Message = message;
			this.Level = lml;
			this.MaskDebug = maskDebug;
			this.LogName = logName;
		}
	}
	#endregion LogListenerEventArgs Class

	#region Log Class
	/// <summary>
	///     Log class for writing debug/log data to files.
	/// </summary>
	public sealed class Log : IDisposable
	{
		#region Fields

		/// <summary>
		///     File stream used for kepping the log file open.
		/// </summary>
		private FileStream log;
		/// <summary>
		///     Writer used for writing to the log file.
		/// </summary>
		private StreamWriter writer;
		/// <summary>
		///     Level of detail for this log.
		/// </summary>
		private LoggingLevel logLevel;
		/// <summary>
		///     Debug output enabled?
		/// </summary>
		private bool debugOutput;
		/// <summary>
		///		flag to indicate object already disposed.
		/// </summary>
		private bool _isDisposed;
		/// <summary>
		///     LogMessageLevel + LoggingLevel > LOG_THRESHOLD = message logged.
		/// </summary>
		const int LogThreshold = 4;

		private string mLogName;

		#endregion Fields

		public event EventHandler<LogListenerEventArgs> MessageLogged;

		#region Constructors

		/// <summary>
		///     Constructor.  Creates a log file that also logs debug output.
		/// </summary>
		/// <param name="fileName">Name of the log file to open.</param>
		public Log( string fileName )
			: this( fileName, true )
		{
		}

		/// <summary>
		///     Constructor.
		/// </summary>
		/// <param name="fileName">Name of the log file to open.</param>
		/// <param name="debugOutput">Write log messages to the debug output?</param>
		public Log( string fileName, bool debugOutput )
		{
			this.mLogName = fileName;
			this.MessageLogged = null;

			this.debugOutput = debugOutput;
			logLevel = LoggingLevel.Normal;

			if ( fileName != null )
			{
				try
				{
#if !( ANDROID )

					// create the log file, or open
					log = File.Open( fileName, FileMode.Create, FileAccess.Write, FileShare.Read );

					// get a stream writer using the file stream
					writer = new StreamWriter( log );
					writer.AutoFlush = true;	//always flush after write
#endif
				}
				catch
				{
				}
			}

		}

		~Log()
		{
			Dispose();
		}

		#endregion Constructors

		#region Properties

		/// <summary>
		///     Gets/Sets the level of the detail for this log.
		/// </summary>
		/// <value></value>
		public LoggingLevel LogDetail
		{
			get
			{
				return logLevel;
			}
			set
			{
				logLevel = value;
			}
		}

		#endregion Properties

		#region Methods

		/// <summary>
		///     Write a message to the log.
		/// </summary>
		/// <remarks>
		///     Message is written with a LogMessageLevel of Normal, and debug output is not written.
		/// </remarks>
		/// <param name="message">Message to write, which can include string formatting tokens.</param>
		/// <param name="substitutions">
		///     When message includes string formatting tokens, these are the values to
		///     inject into the formatted string.
		/// </param>
		public void Write( string message, params object[] substitutions )
		{
			Write( LogMessageLevel.Normal, false, message, substitutions );
		}

		/// <summary>
		///     Write a message to the log.
		/// </summary>
		/// <remarks>
		///     Message is written with a LogMessageLevel of Normal, and debug output is not written.
		/// </remarks>
		/// <param name="maskDebug">If true, debug output will not be written.</param>
		/// <param name="message">Message to write, which can include string formatting tokens.</param>
		/// <param name="substitutions">
		///     When message includes string formatting tokens, these are the values to
		///     inject into the formatted string.
		/// </param>
		public void Write( bool maskDebug, string message, params object[] substitutions )
		{
			Write( LogMessageLevel.Normal, maskDebug, message, substitutions );
		}

		/// <summary>
		///     Write a message to the log.
		/// </summary>
		/// <param name="level">Importance of this logged message.</param>
		/// <param name="maskDebug">If true, debug output will not be written.</param>
		/// <param name="message">Message to write, which can include string formatting tokens.</param>
		/// <param name="substitutions">
		///     When message includes string formatting tokens, these are the values to
		///     inject into the formatted string.
		/// </param>
		public void Write( LogMessageLevel level, bool maskDebug, string message, params object[] substitutions )
		{
			if ( _isDisposed )
				return;

			if ( message == null )
				throw new ArgumentNullException( "The log message cannot be null" );
			if ( ( (int)logLevel + (int)level ) > LogThreshold )
				return;	//too verbose a message to write

			// construct the log message
			if ( substitutions != null && substitutions.Length > 0 )
			{
				message = string.Format( message, substitutions );
			}

			// write the the debug output if requested
			if ( debugOutput && !maskDebug )
			{
				System.Diagnostics.Debug.WriteLine( message );
			}

			if ( writer != null && writer.BaseStream != null )
			{

				// prepend the current time to the message
				message = string.Format( "[{0}] {1}", DateTime.Now.ToString( "hh:mm:ss" ), message );

				// write the message and flush the buffer
				writer.WriteLine( message );
				//writer auto-flushes
			}

			FireMessageLogged( level, maskDebug, message );
		}

		private void FireMessageLogged( LogMessageLevel level, bool maskDebug, string message )
		{
			// Now fire the MessageLogged event
			if ( this.MessageLogged != null )
			{
				LogListenerEventArgs args = new LogListenerEventArgs( message, level, maskDebug, this.mLogName );
				this.MessageLogged( this, args );
			}
		}

		#endregion Methods

		#region IDisposable Members

		/// <summary>
		///     Called to dispose of this objects resources.
		/// </summary>
		/// <remarks>
		///     For the log, closes any open file streams and file writers.
		/// </remarks>
		public void Dispose()
		{
			try
			{
				if ( writer != null )
					writer.Close();

				if ( log != null )
					log.Close();
			}
			catch
			{
			}
			_isDisposed = true;
		}

		#endregion IDisposable Members
	}
	#endregion Log Class
}