/* 
 * 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.Linq;
using System.Text;
using ThoughtWorks.CruiseControl.Remote;
using ThoughtWorks.CruiseControl.Remote.Messages;
using System.Runtime.Remoting;

namespace FastForward.Cache
{
    public class CacheConnection
        : ServerConnectionBase, IServerConnection, IDisposable
    {
        #region Private fields
        private const string cacheUri = "fastforwardcache.rem";
        private readonly Uri serverAddress;
        private IMessageProcessor client;
        private bool isBusy;
        #endregion

        #region Constructors
        /// <summary>
        /// Initialises a new <see cref="CacheConnection"/> to a remote server.
        /// </summary>
        /// <param name="serverAddress">The address of the remote server.</param>
        public CacheConnection(string serverAddress)
            : this(new Uri(serverAddress))
        {
        }

        /// <summary>
        /// Initialises a new <see cref="CacheConnection"/> to a remote server.
        /// </summary>
        /// <param name="serverAddress">The address of the remote server.</param>
        public CacheConnection(Uri serverAddress)
        {
            UriBuilder builder = new UriBuilder(serverAddress);
            if (builder.Port == -1) builder.Port = 23571;
            this.serverAddress = new Uri(builder.Uri, "/" + cacheUri);
        }
        #endregion

        #region Public properties
        #region Type
        /// <summary>
        /// The type of connection.
        /// </summary>
        public string Type
        {
            get { return "FastForward.NET Cache (TCP)"; }
        }
        #endregion

        #region ServerName
        /// <summary>
        /// The name of the server that this connection is for.
        /// </summary>
        public string ServerName
        {
            get { return serverAddress.Host; }
        }
        #endregion

        #region IsBusy
        /// <summary>
        /// Is this connection busy performing an operation.
        /// </summary>
        public bool IsBusy
        {
            get { return isBusy; }
        }
        #endregion

        #region Address
        /// <summary>
        /// The address of the client.
        /// </summary>
        public virtual string Address
        {
            get { return serverAddress.AbsoluteUri; }
        }
        #endregion
        #endregion

        #region Public methods
        #region SendMessage()
        /// <summary>
        /// Sends a message via HTTP.
        /// </summary>
        /// <param name="action"></param>
        /// <param name="request"></param>
        /// <returns></returns>
        public virtual Response SendMessage(string action, ServerRequest request)
        {
            // Initialise the connection and send the message
            try
            {
                InitialiseRemoting();
                FireRequestSending(action, request);
                var result = client.ProcessMessage(action, request);
                FireResponseReceived(action, result);
                return result;
            }
            catch (Exception error)
            {
                // Replace the original exception with a communications exception
                throw new CommunicationsException(error.Message);
            }
        }
        #endregion

        #region SendMessageAsync()
        /// <summary>
        /// Sends a message to a remote server asychronously.
        /// </summary>
        /// <param name="action">The action to perform.</param>
        /// <param name="request">The request to send to the server.</param>
        public virtual void SendMessageAsync(string action, ServerRequest request)
        {
            SendMessageAsync(action, request, null);
        }

        /// <summary>
        /// Sends a message to a remote server asychronously.
        /// </summary>
        /// <param name="action">The action to perform.</param>
        /// <param name="request">The request to send to the server.</param>
        /// <param name="userState">Any user state data.</param>
        /// <remarks>
        /// This operation will still be done in a synchronous mode.
        /// </remarks>
        public virtual void SendMessageAsync(string action, ServerRequest request, object userState)
        {
            if (isBusy) throw new InvalidOperationException();

            try
            {
                isBusy = true;
                InitialiseRemoting();
                var result = client.ProcessMessage(action, request);

                if (SendMessageCompleted != null)
                {
                    var args = new MessageReceivedEventArgs(result, null, false, userState);
                    SendMessageCompleted(this, args);
                }
            }
            catch (Exception error)
            {
                if (SendMessageCompleted != null)
                {
                    var args = new MessageReceivedEventArgs(null, error, false, userState);
                    SendMessageCompleted(this, args);
                }
            }
            finally
            {
                isBusy = false;
            }
        }
        #endregion

        #region CancelAsync()
        /// <summary>
        /// Cancels an asynchronous operation.
        /// </summary>
        public virtual void CancelAsync()
        {
            CancelAsync(null);
        }

        /// <summary>
        /// Cancels an asynchronous operation.
        /// </summary>
        /// <param name="userState"></param>
        public void CancelAsync(object userState)
        {
            // .NET remoting operations are not asynchronous, therefore can't cancel anything
        }
        #endregion

        #region Dispose()
        /// <summary>
        /// Disposes the .NET remoting client.
        /// </summary>
        public virtual void Dispose()
        {
            client = null;
        }
        #endregion
        #endregion

        #region Public events
        #region SendMessageCompleted
        /// <summary>
        /// A SendMessageAsync has completed.
        /// </summary>
        public event EventHandler<MessageReceivedEventArgs> SendMessageCompleted;
        #endregion
        #endregion

        #region Private methods
        #region InitialiseRemoting()
        /// <summary>
        /// Initialises the client connection.
        /// </summary>
        private void InitialiseRemoting()
        {
            if (client == null)
            {
                // Initialise the actual client
                client = RemotingServices.Connect(typeof(IMessageProcessor),
                    serverAddress.AbsoluteUri) as IMessageProcessor;
            }
        }
        #endregion
        #endregion
    }
}