/*
 * 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 OpenSimulator 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.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Reflection;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading;
using System.Timers;
using log4net;
using log4net.Appender;
using log4net.Core;
using log4net.Repository;
using OpenMetaverse;
using OpenMetaverse.StructuredData;
using OpenSim.Framework;
using OpenSim.Framework.Console;
using OpenSim.Framework.Monitoring;
using OpenSim.Framework.Servers;
using OpenSim.Framework.Servers.HttpServer;
using Timer=System.Timers.Timer;

namespace OpenSim.Framework.Servers
{
    /// <summary>
    /// Common base for the main OpenSimServers (user, grid, inventory, region, etc)
    /// </summary>
    public abstract class BaseOpenSimServer : ServerBase
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        /// <summary>
        /// This will control a periodic log printout of the current 'show stats' (if they are active) for this
        /// server.
        /// </summary>
        private Timer m_periodicDiagnosticsTimer = new Timer(60 * 60 * 1000);

        protected string m_pidFile = String.Empty;
        
        /// <summary>
        /// Random uuid for private data 
        /// </summary>
        protected string m_osSecret = String.Empty;

        protected BaseHttpServer m_httpServer;
        public BaseHttpServer HttpServer
        {
            get { return m_httpServer; }
        }

        public BaseOpenSimServer() : base()
        {
            // Random uuid for private data
            m_osSecret = UUID.Random().ToString();

            m_periodicDiagnosticsTimer.Elapsed += new ElapsedEventHandler(LogDiagnostics);
            m_periodicDiagnosticsTimer.Enabled = true;
        }
        
        /// <summary>
        /// Must be overriden by child classes for their own server specific startup behaviour.
        /// </summary>
        protected virtual void StartupSpecific()
        {
            if (m_console == null)
                return;

            RegisterCommonCommands();
            
            m_console.Commands.AddCommand("General", false, "quit",
                    "quit",
                    "Quit the application", HandleQuit);

            m_console.Commands.AddCommand("General", false, "shutdown",
                    "shutdown",
                    "Quit the application", HandleQuit);

            m_console.Commands.AddCommand("General", false, "show threads",
                    "show threads",
                    "Show thread status", HandleShow);

            m_console.Commands.AddCommand("General", false, "show version",
                    "show version",
                    "Show server version", HandleShow);

            m_console.Commands.AddCommand("General", false, "threads abort",
                    "threads abort <thread-id>",
                    "Abort a managed thread.  Use \"show threads\" to find possible threads.", HandleThreadsAbort);

            m_console.Commands.AddCommand("General", false, "threads show",
                    "threads show",
                    "Show thread status.  Synonym for \"show threads\"",
                    (string module, string[] args) => Notice(GetThreadsReport()));

            m_console.Commands.AddCommand("General", false, "force gc",
                    "force gc",
                    "Manually invoke runtime garbage collection.  For debugging purposes",
                    HandleForceGc);
        }

        private void HandleForceGc(string module, string[] args)
        {
            MainConsole.Instance.Output("Manually invoking runtime garbage collection");
            GC.Collect();
        }
        
        /// <summary>
        /// Should be overriden and referenced by descendents if they need to perform extra shutdown processing
        /// </summary>
        public virtual void ShutdownSpecific() {}
        
        /// <summary>
        /// Provides a list of help topics that are available.  Overriding classes should append their topics to the
        /// information returned when the base method is called.
        /// </summary>
        /// 
        /// <returns>
        /// A list of strings that represent different help topics on which more information is available
        /// </returns>
        protected virtual List<string> GetHelpTopics() { return new List<string>(); }

        /// <summary>
        /// Print statistics to the logfile, if they are active
        /// </summary>
        protected void LogDiagnostics(object source, ElapsedEventArgs e)
        {
            StringBuilder sb = new StringBuilder("DIAGNOSTICS\n\n");
            sb.Append(GetUptimeReport());
            sb.Append(StatsManager.SimExtraStats.Report());
            sb.Append(Environment.NewLine);
            sb.Append(GetThreadsReport());

            m_log.Debug(sb);
        }

        /// <summary>
        /// Get a report about the registered threads in this server.
        /// </summary>
        protected string GetThreadsReport()
        {
            // This should be a constant field.
            string reportFormat = "{0,6}   {1,35}   {2,16}   {3,13}   {4,10}   {5,30}";

            StringBuilder sb = new StringBuilder();
            Watchdog.ThreadWatchdogInfo[] threads = Watchdog.GetThreadsInfo();

            sb.Append(threads.Length + " threads are being tracked:" + Environment.NewLine);

            int timeNow = Environment.TickCount & Int32.MaxValue;

            sb.AppendFormat(reportFormat, "ID", "NAME", "LAST UPDATE (MS)", "LIFETIME (MS)", "PRIORITY", "STATE");
            sb.Append(Environment.NewLine);

            foreach (Watchdog.ThreadWatchdogInfo twi in threads)
            {
                Thread t = twi.Thread;
                
                sb.AppendFormat(
                    reportFormat,
                    t.ManagedThreadId,
                    t.Name,
                    timeNow - twi.LastTick,
                    timeNow - twi.FirstTick,
                    t.Priority,
                    t.ThreadState);

                sb.Append("\n");
            }

            sb.Append("\n");

            // For some reason mono 2.6.7 returns an empty threads set!  Not going to confuse people by reporting
            // zero active threads.
            int totalThreads = Process.GetCurrentProcess().Threads.Count;
            if (totalThreads > 0)
                sb.AppendFormat("Total threads active: {0}\n\n", totalThreads);

            sb.Append("Main threadpool (excluding script engine pools)\n");
            sb.Append(Util.GetThreadPoolReport());

            return sb.ToString();
        }

        /// <summary>
        /// Performs initialisation of the scene, such as loading configuration from disk.
        /// </summary>
        public virtual void Startup()
        {
            m_log.Info("[STARTUP]: Beginning startup processing");
            
            m_log.Info("[STARTUP]: OpenSimulator version: " + m_version + Environment.NewLine);
            // clr version potentially is more confusing than helpful, since it doesn't tell us if we're running under Mono/MS .NET and
            // the clr version number doesn't match the project version number under Mono.
            //m_log.Info("[STARTUP]: Virtual machine runtime version: " + Environment.Version + Environment.NewLine);
            m_log.InfoFormat(
                "[STARTUP]: Operating system version: {0}, .NET platform {1}, {2}-bit\n",
                Environment.OSVersion, Environment.OSVersion.Platform, Util.Is64BitProcess() ? "64" : "32");
            
            StartupSpecific();
            
            TimeSpan timeTaken = DateTime.Now - m_startuptime;
            
            m_log.InfoFormat(
                "[STARTUP]: Non-script portion of startup took {0}m {1}s.  PLEASE WAIT FOR LOGINS TO BE ENABLED ON REGIONS ONCE SCRIPTS HAVE STARTED.",
                timeTaken.Minutes, timeTaken.Seconds);
        }

        /// <summary>
        /// Should be overriden and referenced by descendents if they need to perform extra shutdown processing
        /// </summary>
        public virtual void Shutdown()
        {
            ShutdownSpecific();
            
            m_log.Info("[SHUTDOWN]: Shutdown processing on main thread complete.  Exiting...");
            RemovePIDFile();
            
            Environment.Exit(0);
        }

        private void HandleQuit(string module, string[] args)
        {
            Shutdown();
        }

        public override void HandleShow(string module, string[] cmd)
        {
            base.HandleShow(module, cmd);

            List<string> args = new List<string>(cmd);

            args.RemoveAt(0);

            string[] showParams = args.ToArray();

            switch (showParams[0])
            {
                case "threads":
                    Notice(GetThreadsReport());
                    break;

                case "version":
                    Notice(GetVersionText());
                    break;
            }
        }

        public virtual void HandleThreadsAbort(string module, string[] cmd)
        {
            if (cmd.Length != 3)
            {
                MainConsole.Instance.Output("Usage: threads abort <thread-id>");
                return;
            }

            int threadId;
            if (!int.TryParse(cmd[2], out threadId))
            {
                MainConsole.Instance.Output("ERROR: Thread id must be an integer");
                return;
            }

            if (Watchdog.AbortThread(threadId))
                MainConsole.Instance.OutputFormat("Aborted thread with id {0}", threadId);
            else
                MainConsole.Instance.OutputFormat("ERROR - Thread with id {0} not found in managed threads", threadId);
        }       
        
        protected void CreatePIDFile(string path)
        {
            try
            {
                string pidstring = System.Diagnostics.Process.GetCurrentProcess().Id.ToString();
                FileStream fs = File.Create(path);

                Byte[] buf = Encoding.ASCII.GetBytes(pidstring);
                fs.Write(buf, 0, buf.Length);
                fs.Close();
                m_pidFile = path;
            }
            catch (Exception)
            {
            }
        }
        
        public string osSecret {
            // Secret uuid for the simulator
            get { return m_osSecret; }            
        }

        public string StatReport(IOSHttpRequest httpRequest)
        {
            // If we catch a request for "callback", wrap the response in the value for jsonp
            if (httpRequest.Query.ContainsKey("callback"))
            {
                return httpRequest.Query["callback"].ToString() + "(" + StatsManager.SimExtraStats.XReport((DateTime.Now - m_startuptime).ToString() , m_version) + ");";
            } 
            else 
            {
                return StatsManager.SimExtraStats.XReport((DateTime.Now - m_startuptime).ToString() , m_version);
            }
        }
           
        protected void RemovePIDFile()
        {
            if (m_pidFile != String.Empty)
            {
                try
                {
                    File.Delete(m_pidFile);
                    m_pidFile = String.Empty;
                }
                catch (Exception)
                {
                }
            }
        }
    }
}