/* 
 * 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 NLog;
using ThoughtWorks.CruiseControl.Remote;
using ThoughtWorks.CruiseControl.Remote.Messages;

namespace FastForward.Cache
{
    /// <summary>
    /// An engine for caching server information.
    /// </summary>
    public class CacheEngine
        : IDisposable
    {
        #region Private fields
        private Dictionary<string, ServerStateCache> clients = new Dictionary<string, ServerStateCache>();
        private Logger logger;
        private DatabaseConnection database;
        #endregion

        #region Constructors
        /// <summary>
        /// Initialise the cache engine.
        /// </summary>
        /// <param name="logger"></param>
        public CacheEngine(Logger logger)
        {
            this.logger = logger;
        }
        #endregion

        #region Public methods
        #region Initialise()
        /// <summary>
        /// Initialise the cache engine.
        /// </summary>
        /// <param name="configuration">The configuration to use.</param>
        public void Initialise(CacheConfiguration configuration)
        {
            // Initialise a new client factory that forces each instance to be unique
            logger.Debug("Starting client factory");
            var factory = new CruiseServerClientFactory { UseClientCaching = false };

            // Initialise the database
            logger.Debug("Initialising local cache database");
            database = DatabaseConnection.Initialise(configuration.DatabaseType, configuration.ConnectionString);

            foreach (var server in configuration.Servers)
            {
                // Initialise each client
                logger.Info("Starting client: {0} [{1}]", server.Address, server.TransportMode);
                CruiseServerClientBase client = null;
                switch (server.TransportMode)
                {
                    case ServerTransportMode.Default:
                        client = factory.GenerateClient(server.Address, server.TargetServer, server.Settings);
                        break;
                    case ServerTransportMode.Http:
                        client = factory.GenerateHttpClient(server.Address, server.TargetServer, server.Settings);
                        break;
                    case ServerTransportMode.Remoting:
                        client = factory.GenerateRemotingClient(server.Address, server.TargetServer, server.Settings);
                        break;
                    case ServerTransportMode.Cache:
                        client = InitialiseCacheConnection(server);
                        break;
                }

                // Add the client to the dictionary
                clients.Add(server.Name, new ServerStateCache(logger, client, server.PollingInterval, database));
            }
        }
        #endregion

        #region Dispose()
        /// <summary>
        /// Clean up.
        /// </summary>
        public void Dispose()
        {
            foreach (var client in clients.Values)
            {
                logger.Info("Disposing client: {0}", client.Client.Address);
                client.Dispose();
            }
        }
        #endregion

        #region ProcessMessage()
        /// <summary>
        /// Process a message for the remote server.
        /// </summary>
        /// <param name="action"></param>
        /// <param name="request"></param>
        /// <returns></returns>
        public Response ProcessMessage(string action, ServerRequest request)
        {
            if (clients.ContainsKey(request.ServerName))
            {
                var client = clients[request.ServerName];
                var response = client.ProcessMessage(action, request);
                return response;
            }
            else
            {
                throw new ApplicationException("Server not found");
            }
        }
        #endregion
        #endregion

        #region Private methods
        #region InitialiseCacheConnection()
        /// <summary>
        /// Initialise a connection to a cache server.
        /// </summary>
        /// <param name="server"></param>
        /// <returns></returns>
        private CruiseServerClientBase InitialiseCacheConnection(ServerConfiguration server)
        {
            var connection = new CacheConnection(server.Address);
            var actualConnection = CruiseServerClientFactory.BuildUpConnection(connection, server.Settings);
            var client = new CruiseServerClient(actualConnection);
            client.TargetServer = server.TargetServer;
            return client;
        }
        #endregion
        #endregion
    }
}