/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the OpenSim Project nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Text.RegularExpressions;
using log4net.Appender;
using log4net.Core;

namespace OpenSim.Framework.Console
{
    /// <summary>
    /// Writes log information out onto the console
    /// </summary>
    public class OpenSimAppender : AnsiColorTerminalAppender
    {
        private static readonly ConsoleColor[] Colors = {
            ConsoleColor.DarkBlue,
            ConsoleColor.DarkGreen,
            ConsoleColor.DarkCyan,
            ConsoleColor.DarkMagenta,
            ConsoleColor.DarkYellow,
            ConsoleColor.Gray,
            ConsoleColor.DarkGray,
            ConsoleColor.Blue,
            ConsoleColor.Green,
            ConsoleColor.Cyan,
            ConsoleColor.Magenta,
            ConsoleColor.Yellow
        };

        override protected void Append(LoggingEvent le)
        {
            try
            {
                string loggingMessage = RenderLoggingEvent(le);

                string regex = @"^(?<Front>.*?)\[(?<Category>[^\]]+)\]:?(?<End>.*)";

                Regex RE = new Regex(regex, RegexOptions.Multiline);
                MatchCollection matches = RE.Matches(loggingMessage);

                // Get some direct matches $1 $4 is a
                if (matches.Count == 1)
                {
                    System.Console.Write(matches[0].Groups["Front"].Value);
                    System.Console.Write("[");

                    WriteColorText(DeriveColor(matches[0].Groups["Category"].Value), matches[0].Groups["Category"].Value);
                    System.Console.Write("]:");

                    if (le.Level == Level.Error)
                    {
                        WriteColorText(ConsoleColor.Red, matches[0].Groups["End"].Value);
                    }
                    else if (le.Level == Level.Warn)
                    {
                        WriteColorText(ConsoleColor.Yellow, matches[0].Groups["End"].Value);
                    }
                    else
                    {
                        System.Console.Write(matches[0].Groups["End"].Value);
                    }
                    System.Console.WriteLine();
                }
                else
                {
                    System.Console.Write(loggingMessage);
                }
            }
            catch (Exception e)
            {
                System.Console.WriteLine("Couldn't write out log message: {0}", e.ToString());
            }
        }

        private void WriteColorText(ConsoleColor color, string sender)
        {
            try
            {
                lock (this)
                {
                    try
                    {
                        System.Console.ForegroundColor = color;
                        System.Console.Write(sender);
                        System.Console.ResetColor();
                    }
                    catch (ArgumentNullException)
                    {
                        // Some older systems dont support coloured text.
                        System.Console.WriteLine(sender);
                    }
                }
            }
            catch (ObjectDisposedException)
            {
            }
        }

        private static ConsoleColor DeriveColor(string input)
        {
            // it is important to do Abs, hash values can be negative
            return Colors[(Math.Abs(input.ToUpper().GetHashCode()) % Colors.Length)];
        }
    }
}