/* 
 * Copyright (c) 2009 Craig Sutherland
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.ServiceProcess;
using System.Text;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Configuration;
using NLog;

namespace FastForward.Cache
{
    public partial class CacheService 
        : ServiceBase
    {
        private CacheConfiguration configuration;
        private CacheEngine engine;
        private RemotingServer remotingServer;
        private bool isLoaded = false;
        private bool isDisposed = false;
        private object lockObject = new object();
        private Logger logger = LogManager.GetCurrentClassLogger();

        public CacheService()
        {
            RemotingConfiguration.Configure(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile, false);
            ServiceName = "FastForward.Cache";
        }

        public void Run(string[] args)
        {
            // Ensure we only start once
            lock (lockObject)
            {
                if (isLoaded) return;
                isLoaded = true;
            }

            // Load the configuration
            logger.Debug("Loading configuration");
            configuration = ConfigurationManager.GetSection("FastForward.Cache") as CacheConfiguration;
            if (configuration == null)
            {
                var error = new Exception("Unable to load configuration");
                logger.Fatal(error.Message);
                throw error;
            }

            // Initialise the engine
            try
            {
                logger.Debug("Initialising cache engine");
                engine = new CacheEngine(logger);
                engine.Initialise(configuration);
            }
            catch (Exception error)
            {
                logger.Fatal("Unable to start engine: {0}", error.Message);
                throw;
            }

            // Initialise remoting
            if (!string.IsNullOrEmpty(configuration.RemotingAddress))
            {
                logger.Debug("Initialising remoting");
                remotingServer = new RemotingServer(logger, engine);
                RemotingServices.Marshal(remotingServer, configuration.RemotingAddress);

                foreach (var channel in ChannelServices.RegisteredChannels)
                {
                    logger.Info("Remoting channel {0} initialised", channel.ChannelName);
                    var receiver = channel as IChannelReceiver;
                    if (receiver != null)
                    {
                        foreach (string url in receiver.GetUrlsForUri(configuration.RemotingAddress))
                        {
                            logger.Info("Listening on url: {0}", url);
                        }
                    }
                }
            }
            isDisposed = false;
        }

        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing);

            // Ensure we only dispose once
            lock (lockObject)
            {
                if (isDisposed) return;
                isDisposed = true;
            }

            // Clean up remoting
            if (!string.IsNullOrEmpty(configuration.RemotingAddress))
            {
                logger.Debug("Terminating remoting");
                RemotingServices.Disconnect(remotingServer);
                foreach (var channel in ChannelServices.RegisteredChannels)
                {
                    ChannelServices.UnregisterChannel(channel);
                }
                remotingServer = null;
            }

            // Clean up everything else
            logger.Debug("Terminating cache engine");
            engine.Dispose();
            engine = null;
            configuration = null;
            isLoaded = false;
        }

        protected override void OnStart(string[] args)
        {
            logger.Info("Start received");
            Run(args);
        }

        protected override void OnStop()
        {
            logger.Info("Stop received");
            Dispose();
        }
    }
}